Complete overhaul of batch system on server-side

Added batch methods to BulletinBoardUtils
Related changes in BulletinBoardDigest and BulletinBoardSignature

Merge remote-tracking branch 'origin/master' into Cached-Client

Conflicts:
	bulletin-board-client/src/main/java/meerkat/bulletinboard/SimpleBulletinBoardClient.java
	bulletin-board-client/src/main/java/meerkat/bulletinboard/ThreadedBulletinBoardClient.java
	bulletin-board-server/src/main/java/meerkat/bulletinboard/sqlserver/BulletinBoardSQLServer.java
	bulletin-board-server/src/main/java/meerkat/bulletinboard/sqlserver/H2QueryProvider.java
	bulletin-board-server/src/main/java/meerkat/bulletinboard/sqlserver/MySQLQueryProvider.java
	bulletin-board-server/src/main/java/meerkat/bulletinboard/webapp/BulletinBoardWebApp.java
	bulletin-board-server/src/main/proto/meerkat/bulletin_board_server.proto
	meerkat-common/src/main/java/meerkat/bulletinboard/BulletinBoardClient.java
	meerkat-common/src/main/java/meerkat/bulletinboard/BulletinBoardServer.java

.gitignore

@@ -13,4 +13,5 @@ out
 *.prefs
 *.project
 *.classpath
-bulletin-board-server/local-instances/meerkat.db
+*.db
+*.sql

bulletin-board-client/src/main/java/meerkat/bulletinboard/BatchDataContainer.java

@@ -1,7 +1,6 @@
 package meerkat.bulletinboard;
 
-import com.google.protobuf.ByteString;
+import meerkat.protobuf.BulletinBoardAPI.BatchChunk;
-import meerkat.protobuf.BulletinBoardAPI.BatchData;
 
 import java.util.List;
 
@@ -13,13 +12,13 @@ public class BatchDataContainer {
 
     public final byte[] signerId;
     public final int batchId;
-    public final List<BatchData> batchDataList;
+    public final List<BatchChunk> batchChunkList;
     public final int startPosition;
 
-    public BatchDataContainer(byte[] signerId, int batchId, List<BatchData> batchDataList, int startPosition) {
+    public BatchDataContainer(byte[] signerId, int batchId, List<BatchChunk> batchChunkList, int startPosition) {
         this.signerId = signerId;
         this.batchId = batchId;
-        this.batchDataList = batchDataList;
+        this.batchChunkList = batchChunkList;
         this.startPosition = startPosition;
     }
 }

bulletin-board-client/src/main/java/meerkat/bulletinboard/CachedBulletinBoardClient.java

@@ -162,13 +162,13 @@ public class CachedBulletinBoardClient implements SubscriptionBulletinBoardClien
     }
 
     @Override
-    public void postBatchData(final byte[] signerId, final int batchId, final List<BatchData> batchDataList,
+    public void postBatchData(final byte[] signerId, final int batchId, final List<BatchChunk> batchChunkList,
                               final int startPosition, final FutureCallback<Boolean> callback) {
 
-        localClient.postBatchData(signerId, batchId, batchDataList, startPosition, new FutureCallback<Boolean>() {
+        localClient.postBatchData(signerId, batchId, batchChunkList, startPosition, new FutureCallback<Boolean>() {
             @Override
             public void onSuccess(Boolean result) {
-                remoteClient.postBatchData(signerId, batchId, batchDataList, startPosition, callback);
+                remoteClient.postBatchData(signerId, batchId, batchChunkList, startPosition, callback);
             }
 
             @Override
@@ -181,12 +181,12 @@ public class CachedBulletinBoardClient implements SubscriptionBulletinBoardClien
     }
 
     @Override
-    public void postBatchData(final byte[] signerId, final int batchId, final List<BatchData> batchDataList, final FutureCallback<Boolean> callback) {
+    public void postBatchData(final byte[] signerId, final int batchId, final List<BatchChunk> batchChunkList, final FutureCallback<Boolean> callback) {
 
-        localClient.postBatchData(signerId, batchId, batchDataList, new FutureCallback<Boolean>() {
+        localClient.postBatchData(signerId, batchId, batchChunkList, new FutureCallback<Boolean>() {
             @Override
             public void onSuccess(Boolean result) {
-                remoteClient.postBatchData(signerId, batchId, batchDataList, callback);
+                remoteClient.postBatchData(signerId, batchId, batchChunkList, callback);
             }
 
             @Override
@@ -199,13 +199,13 @@ public class CachedBulletinBoardClient implements SubscriptionBulletinBoardClien
     }
 
     @Override
-    public void postBatchData(final ByteString signerId, final int batchId, final List<BatchData> batchDataList,
+    public void postBatchData(final ByteString signerId, final int batchId, final List<BatchChunk> batchChunkList,
                               final int startPosition, final FutureCallback<Boolean> callback) {
 
-        localClient.postBatchData(signerId, batchId, batchDataList, startPosition, new FutureCallback<Boolean>() {
+        localClient.postBatchData(signerId, batchId, batchChunkList, startPosition, new FutureCallback<Boolean>() {
             @Override
             public void onSuccess(Boolean result) {
-                remoteClient.postBatchData(signerId, batchId, batchDataList, startPosition, callback);
+                remoteClient.postBatchData(signerId, batchId, batchChunkList, startPosition, callback);
             }
 
             @Override
@@ -218,12 +218,12 @@ public class CachedBulletinBoardClient implements SubscriptionBulletinBoardClien
     }
 
     @Override
-    public void postBatchData(final ByteString signerId, final int batchId, final List<BatchData> batchDataList, final FutureCallback<Boolean> callback) {
+    public void postBatchData(final ByteString signerId, final int batchId, final List<BatchChunk> batchChunkList, final FutureCallback<Boolean> callback) {
 
-        localClient.postBatchData(signerId, batchId, batchDataList, new FutureCallback<Boolean>() {
+        localClient.postBatchData(signerId, batchId, batchChunkList, new FutureCallback<Boolean>() {
             @Override
             public void onSuccess(Boolean result) {
-                remoteClient.postBatchData(signerId, batchId, batchDataList, callback);
+                remoteClient.postBatchData(signerId, batchId, batchChunkList, callback);
             }
 
             @Override

bulletin-board-client/src/main/java/meerkat/bulletinboard/LocalBulletinBoardClient.java

@@ -92,7 +92,7 @@ public class LocalBulletinBoardClient implements DeletableSubscriptionBulletinBo
                     .setBatchId(completeBatch.getBeginBatchMessage().getBatchId());
 
             int i=0;
-            for (BatchData data : completeBatch.getBatchDataList()){
+            for (BatchChunk data : completeBatch.getBatchDataList()){
 
                 server.postBatchMessage(builder.setSerialNum(i).setData(data).build());
 
@@ -100,7 +100,7 @@ public class LocalBulletinBoardClient implements DeletableSubscriptionBulletinBo
 
             }
 
-            return server.closeBatchMessage(completeBatch.getCloseBatchMessage()).getValue();
+            return server.closeBatch(completeBatch.getCloseBatchMessage()).getValue();
         }
 
     }
@@ -140,13 +140,13 @@ public class LocalBulletinBoardClient implements DeletableSubscriptionBulletinBo
 
         private final ByteString signerId;
         private final int batchId;
-        private final List<BatchData> batchDataList;
+        private final List<BatchChunk> batchChunkList;
         private final int startPosition;
 
-        public BatchDataPoster(ByteString signerId, int batchId, List<BatchData> batchDataList, int startPosition) {
+        public BatchDataPoster(ByteString signerId, int batchId, List<BatchChunk> batchChunkList, int startPosition) {
             this.signerId = signerId;
             this.batchId = batchId;
-            this.batchDataList = batchDataList;
+            this.batchChunkList = batchChunkList;
             this.startPosition = startPosition;
         }
 
@@ -159,7 +159,7 @@ public class LocalBulletinBoardClient implements DeletableSubscriptionBulletinBo
                     .setBatchId(batchId);
 
             int i = startPosition;
-            for (BatchData data : batchDataList){
+            for (BatchChunk data : batchChunkList){
 
                 msgBuilder.setSerialNum(i)
                         .setData(data);
@@ -178,23 +178,23 @@ public class LocalBulletinBoardClient implements DeletableSubscriptionBulletinBo
     }
 
     @Override
-    public void postBatchData(byte[] signerId, int batchId, List<BatchData> batchDataList, int startPosition, FutureCallback<Boolean> callback) {
+    public void postBatchData(byte[] signerId, int batchId, List<BatchChunk> batchChunkList, int startPosition, FutureCallback<Boolean> callback) {
-        postBatchData(ByteString.copyFrom(signerId), batchId, batchDataList, startPosition, callback);
+        postBatchData(ByteString.copyFrom(signerId), batchId, batchChunkList, startPosition, callback);
     }
 
     @Override
-    public void postBatchData(byte[] signerId, int batchId, List<BatchData> batchDataList, FutureCallback<Boolean> callback) {
+    public void postBatchData(byte[] signerId, int batchId, List<BatchChunk> batchChunkList, FutureCallback<Boolean> callback) {
-        postBatchData(signerId, batchId, batchDataList, 0, callback);
+        postBatchData(signerId, batchId, batchChunkList, 0, callback);
     }
 
     @Override
-    public void postBatchData(ByteString signerId, int batchId, List<BatchData> batchDataList, int startPosition, FutureCallback<Boolean> callback) {
+    public void postBatchData(ByteString signerId, int batchId, List<BatchChunk> batchChunkList, int startPosition, FutureCallback<Boolean> callback) {
-        Futures.addCallback(executorService.submit(new BatchDataPoster(signerId, batchId, batchDataList, startPosition)), callback);
+        Futures.addCallback(executorService.submit(new BatchDataPoster(signerId, batchId, batchChunkList, startPosition)), callback);
     }
 
     @Override
-    public void postBatchData(ByteString signerId, int batchId, List<BatchData> batchDataList, FutureCallback<Boolean> callback) {
+    public void postBatchData(ByteString signerId, int batchId, List<BatchChunk> batchChunkList, FutureCallback<Boolean> callback) {
-        postBatchData(signerId, batchId, batchDataList, 0, callback);
+        postBatchData(signerId, batchId, batchChunkList, 0, callback);
     }
 
     private class BatchCloser implements Callable<Boolean> {
@@ -208,7 +208,7 @@ public class LocalBulletinBoardClient implements DeletableSubscriptionBulletinBo
 
         @Override
         public Boolean call() throws Exception {
-            return server.closeBatchMessage(msg).getValue();
+            return server.closeBatch(msg).getValue();
         }
 
     }
@@ -287,7 +287,7 @@ public class LocalBulletinBoardClient implements DeletableSubscriptionBulletinBo
 
     }
 
-    private class BatchDataReader implements Callable<List<BatchData>> {
+    private class BatchDataReader implements Callable<List<BatchChunk>> {
 
         private final BatchSpecificationMessage batchSpecificationMessage;
 
@@ -296,16 +296,16 @@ public class LocalBulletinBoardClient implements DeletableSubscriptionBulletinBo
         }
 
         @Override
-        public List<BatchData> call() throws Exception {
+        public List<BatchChunk> call() throws Exception {
 
             ByteArrayOutputStream byteOutputStream = new ByteArrayOutputStream();
-            MessageOutputStream<BatchData> outputStream = new MessageOutputStream<>(byteOutputStream);
+            MessageOutputStream<BatchChunk> outputStream = new MessageOutputStream<>(byteOutputStream);
             server.readBatch(batchSpecificationMessage, outputStream);
 
-            MessageInputStream<BatchData> inputStream =
+            MessageInputStream<BatchChunk> inputStream =
                     MessageInputStreamFactory.createMessageInputStream(
                             new ByteArrayInputStream(byteOutputStream.toByteArray()),
-                            BatchData.class);
+                            BatchChunk.class);
 
             return inputStream.asList();
 
@@ -387,7 +387,7 @@ public class LocalBulletinBoardClient implements DeletableSubscriptionBulletinBo
         subscribe(filterList, 0, callback);
     }
 
-    private class CompleteBatchReader implements Callable<CompleteBatch> {
+    private class CompleteBatchReader implements Callable<BulletinBoardMessage> {
 
         private final BatchSpecificationMessage batchSpecificationMessage;
 
@@ -397,7 +397,7 @@ public class LocalBulletinBoardClient implements DeletableSubscriptionBulletinBo
 
 
         @Override
-        public CompleteBatch call() throws Exception {
+        public BulletinBoardMessage call() throws Exception {
 
             final String[] TAGS_TO_REMOVE = {BulletinBoardConstants.BATCH_TAG, BulletinBoardConstants.BATCH_ID_TAG_PREFIX};
 
@@ -407,13 +407,13 @@ public class LocalBulletinBoardClient implements DeletableSubscriptionBulletinBo
                     .build());
 
             ByteArrayOutputStream byteOutputStream = new ByteArrayOutputStream();
-            MessageOutputStream<BatchData> batchOutputStream = new MessageOutputStream<>(byteOutputStream);
+            MessageOutputStream<BatchChunk> batchOutputStream = new MessageOutputStream<>(byteOutputStream);
             server.readBatch(batchSpecificationMessage,batchOutputStream);
 
-            MessageInputStream<BatchData> batchInputStream =
+            MessageInputStream<BatchChunk> batchInputStream =
                     MessageInputStreamFactory.createMessageInputStream(
                             new ByteArrayInputStream(byteOutputStream.toByteArray()),
-                            BatchData.class);
+                            BatchChunk.class);
 
             completeBatch.appendBatchData(batchInputStream.asList());
 
@@ -462,7 +462,7 @@ public class LocalBulletinBoardClient implements DeletableSubscriptionBulletinBo
     }
 
     @Override
-    public void readBatch(BatchSpecificationMessage batchSpecificationMessage, FutureCallback<CompleteBatch> callback) {
+    public void readBatch(BatchSpecificationMessage batchSpecificationMessage, FutureCallback<BulletinBoardMessage> callback) {
         Futures.addCallback(executorService.submit(new CompleteBatchReader(batchSpecificationMessage)), callback);
     }
 
@@ -568,8 +568,8 @@ public class LocalBulletinBoardClient implements DeletableSubscriptionBulletinBo
 
         try {
 
-            List<BatchData> batchDataList = batchDataReader.call();
+            List<BatchChunk> batchChunkList = batchDataReader.call();
-            return new CompleteBatch(batchMessage, batchDataList);
+            return new CompleteBatch(batchMessage, batchChunkList);
 
         } catch (Exception e) {
             throw new CommunicationException("Error reading batch");

bulletin-board-client/src/main/java/meerkat/bulletinboard/SimpleBulletinBoardClient.java

@@ -1,5 +1,6 @@
 package meerkat.bulletinboard;
 
+import com.google.protobuf.BoolValue;
 import com.google.protobuf.ByteString;
 import meerkat.bulletinboard.workers.singleserver.*;
 import meerkat.comm.CommunicationException;
@@ -70,18 +71,13 @@ public class SimpleBulletinBoardClient implements BulletinBoardClient{
                 // Only consider valid responses
                 if (response.getStatusInfo() == Response.Status.OK
                         || response.getStatusInfo() == Response.Status.CREATED) {
-                    response.readEntity(BoolMsg.class).getValue();
+                    response.readEntity(BoolValue.class).getValue();
                 } else {
                     throw new CommunicationException("Server returned error. Status was: " + response.getStatus());
                 }
             }
         } catch (Exception e) { // Occurs only when server replies with valid status but invalid data
-
+            throw new CommunicationException("Error accessing database: " + e.getMessage());
-            throw new CommunicationException("Server returned invalid data type: " + e.getMessage());
-
-        } finally {
-            if (response != null)
-                response.close();
         }
 
         // Calculate the correct message ID and return it
@@ -107,12 +103,12 @@ public class SimpleBulletinBoardClient implements BulletinBoardClient{
 
             BatchMessage.Builder builder = BatchMessage.newBuilder().setSignerId(signerID).setBatchId(batchID);
 
-            for (BatchData batchData : completeBatch.getBatchDataList()) {
+            for (BatchChunk batchChunk : completeBatch.getBatchDataList()) {
 
                 SingleServerPostBatchWorker postBatchWorker =
                         new SingleServerPostBatchWorker(
                                 db,
-                                builder.setData(batchData).setSerialNum(pos).build(),
+                                builder.setData(batchChunk).setSerialNum(pos).build(),
                                 0);
 
                 postBatchWorker.call();
@@ -187,6 +183,7 @@ public class SimpleBulletinBoardClient implements BulletinBoardClient{
         for (String db : meerkatDBs) {
 
             try {
+                webTarget = client.target(db).path(BULLETIN_BOARD_SERVER_PATH).path(READ_MESSAGES_PATH);
 
                 SingleServerReadMessagesWorker worker = new SingleServerReadMessagesWorker(db, filterList, 0);
 
@@ -235,9 +232,9 @@ public class SimpleBulletinBoardClient implements BulletinBoardClient{
 
                 SingleServerReadBatchWorker batchWorker = new SingleServerReadBatchWorker(db, batchSpecificationMessage, 0);
 
-                List<BatchData> batchDataList = batchWorker.call();
+                List<BatchChunk> batchChunkList = batchWorker.call();
 
-                CompleteBatch result = new CompleteBatch(batchMessage, batchDataList);
+                CompleteBatch result = new CompleteBatch(batchMessage, batchChunkList);
 
                 return result;
 

bulletin-board-client/src/main/java/meerkat/bulletinboard/SingleServerBulletinBoardClient.java

@@ -6,12 +6,9 @@ import com.google.common.util.concurrent.ListeningScheduledExecutorService;
 import com.google.common.util.concurrent.MoreExecutors;
 import com.google.protobuf.ByteString;
 import meerkat.bulletinboard.workers.singleserver.*;
-import meerkat.comm.CommunicationException;
 import meerkat.protobuf.BulletinBoardAPI.*;
 import meerkat.protobuf.Voting.BulletinBoardClientParams;
-import meerkat.util.BulletinBoardUtils;
 
-import java.util.Arrays;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
@@ -174,7 +171,7 @@ public class SingleServerBulletinBoardClient extends SimpleBulletinBoardClient i
 
         private final FutureCallback<CompleteBatch> callback;
 
-        private List<BatchData> batchDataList;
+        private List<BatchChunk> batchChunkList;
         private BulletinBoardMessage batchMessage;
 
         private AtomicInteger remainingQueries;
@@ -198,7 +195,7 @@ public class SingleServerBulletinBoardClient extends SimpleBulletinBoardClient i
             if (remainingQueries.decrementAndGet() == 0){
 
                 if (callback != null)
-                    callback.onSuccess(new CompleteBatch(batchMessage, batchDataList));
+                    callback.onSuccess(new CompleteBatch(batchMessage, batchChunkList));
             }
 
         }
@@ -213,12 +210,12 @@ public class SingleServerBulletinBoardClient extends SimpleBulletinBoardClient i
         /**
          * @return a FutureCallback for the Batch Data List that ties to this object
          */
-        public FutureCallback<List<BatchData>> asBatchDataListFutureCallback() {
+        public FutureCallback<List<BatchChunk>> asBatchDataListFutureCallback() {
-            return new FutureCallback<List<BatchData>>() {
+            return new FutureCallback<List<BatchChunk>>() {
 
                 @Override
-                public void onSuccess(List<BatchData> result) {
+                public void onSuccess(List<BatchChunk> result) {
-                    batchDataList = result;
+                    batchChunkList = result;
 
                     combineAndReturn();
                 }
@@ -449,7 +446,7 @@ public class SingleServerBulletinBoardClient extends SimpleBulletinBoardClient i
     }
 
     @Override
-    public void postBatchData(ByteString signerId, int batchId, List<BatchData> batchDataList,
+    public void postBatchData(ByteString signerId, int batchId, List<BatchChunk> batchChunkList,
                           int startPosition, FutureCallback<Boolean> callback) {
 
         BatchMessage.Builder builder = BatchMessage.newBuilder()
@@ -458,11 +455,11 @@ public class SingleServerBulletinBoardClient extends SimpleBulletinBoardClient i
 
         // Create a unified callback to aggregate successful posts
 
-        PostBatchDataListCallback listCallback = new PostBatchDataListCallback(batchDataList.size(), callback);
+        PostBatchDataListCallback listCallback = new PostBatchDataListCallback(batchChunkList.size(), callback);
 
         // Iterate through data list
 
-        for (BatchData data : batchDataList) {
+        for (BatchChunk data : batchChunkList) {
             builder.setSerialNum(startPosition).setData(data);
 
             // Create worker with redundancy 1 and MAX_RETRIES retries
@@ -479,24 +476,24 @@ public class SingleServerBulletinBoardClient extends SimpleBulletinBoardClient i
     }
 
     @Override
-    public void postBatchData(ByteString signerId, int batchId, List<BatchData> batchDataList, FutureCallback<Boolean> callback) {
+    public void postBatchData(ByteString signerId, int batchId, List<BatchChunk> batchChunkList, FutureCallback<Boolean> callback) {
 
-        postBatchData(signerId, batchId, batchDataList, 0, callback);
+        postBatchData(signerId, batchId, batchChunkList, 0, callback);
 
     }
 
     @Override
-    public void postBatchData(byte[] signerId, int batchId, List<BatchData> batchDataList,
+    public void postBatchData(byte[] signerId, int batchId, List<BatchChunk> batchChunkList,
                               int startPosition, FutureCallback<Boolean> callback) {
 
-        postBatchData(ByteString.copyFrom(signerId), batchId, batchDataList, startPosition, callback);
+        postBatchData(ByteString.copyFrom(signerId), batchId, batchChunkList, startPosition, callback);
 
     }
 
     @Override
-    public void postBatchData(byte[] signerId, int batchId, List<BatchData> batchDataList, FutureCallback<Boolean> callback) {
+    public void postBatchData(byte[] signerId, int batchId, List<BatchChunk> batchChunkList, FutureCallback<Boolean> callback) {
 
-        postBatchData(signerId, batchId, batchDataList, 0, callback);
+        postBatchData(signerId, batchId, batchChunkList, 0, callback);
 
     }
 

bulletin-board-client/src/main/java/meerkat/bulletinboard/ThreadedBulletinBoardClient.java

@@ -127,10 +127,10 @@ public class ThreadedBulletinBoardClient extends SimpleBulletinBoardClient imple
     }
 
     @Override
-    public void postBatchData(byte[] signerId, int batchId, List<BatchData> batchDataList,
+    public void postBatchData(byte[] signerId, int batchId, List<BatchChunk> batchChunkList,
                               int startPosition, FutureCallback<Boolean> callback) {
 
-        BatchDataContainer batchDataContainer = new BatchDataContainer(signerId, batchId, batchDataList, startPosition);
+        BatchDataContainer batchDataContainer = new BatchDataContainer(signerId, batchId, batchChunkList, startPosition);
 
         // Create job
         MultiServerPostBatchDataWorker worker =
@@ -142,24 +142,24 @@ public class ThreadedBulletinBoardClient extends SimpleBulletinBoardClient imple
     }
 
     @Override
-    public void postBatchData(byte[] signerId, int batchId, List<BatchData> batchDataList, FutureCallback<Boolean> callback) {
+    public void postBatchData(byte[] signerId, int batchId, List<BatchChunk> batchChunkList, FutureCallback<Boolean> callback) {
 
-        postBatchData(signerId, batchId, batchDataList, 0, callback);
+        postBatchData(signerId, batchId, batchChunkList, 0, callback);
 
     }
 
     @Override
-    public void postBatchData(ByteString signerId, int batchId, List<BatchData> batchDataList,
+    public void postBatchData(ByteString signerId, int batchId, List<BatchChunk> batchChunkList,
                               int startPosition, FutureCallback<Boolean> callback) {
 
-        postBatchData(signerId.toByteArray(), batchId, batchDataList, startPosition, callback);
+        postBatchData(signerId.toByteArray(), batchId, batchChunkList, startPosition, callback);
 
     }
 
     @Override
-    public void postBatchData(ByteString signerId, int batchId, List<BatchData> batchDataList, FutureCallback<Boolean> callback) {
+    public void postBatchData(ByteString signerId, int batchId, List<BatchChunk> batchChunkList, FutureCallback<Boolean> callback) {
 
-        postBatchData(signerId, batchId, batchDataList, 0, callback);
+        postBatchData(signerId, batchId, batchChunkList, 0, callback);
 
     }
 
@@ -251,3 +251,4 @@ public class ThreadedBulletinBoardClient extends SimpleBulletinBoardClient imple
     }
 
 }
+==== BASE ====

bulletin-board-client/src/main/java/meerkat/bulletinboard/workers/multiserver/MultiServerPostBatchDataWorker.java

@@ -21,7 +21,7 @@ public class MultiServerPostBatchDataWorker extends MultiServerGenericPostWorker
 
     @Override
     protected void doPost(SingleServerBulletinBoardClient client, BatchDataContainer payload) {
-        client.postBatchData(payload.signerId, payload.batchId, payload.batchDataList, payload.startPosition, this);
+        client.postBatchData(payload.signerId, payload.batchId, payload.batchChunkList, payload.startPosition, this);
     }
 
 

bulletin-board-client/src/main/java/meerkat/bulletinboard/workers/multiserver/MultiServerPostBatchWorker.java

@@ -1,7 +1,6 @@
 package meerkat.bulletinboard.workers.multiserver;
 
 import com.google.common.util.concurrent.FutureCallback;
-import meerkat.bulletinboard.CompleteBatch;
 import meerkat.bulletinboard.SingleServerBulletinBoardClient;
 import meerkat.protobuf.BulletinBoardAPI.BulletinBoardMessage;
 

bulletin-board-client/src/main/java/meerkat/bulletinboard/workers/singleserver/SingleServerCloseBatchWorker.java

@@ -6,7 +6,7 @@ import static meerkat.bulletinboard.BulletinBoardConstants.CLOSE_BATCH_PATH;
 
 /**
  * Created by Arbel Deutsch Peled on 27-Dec-15.
- * Tries to contact server once and perform a close batch operation
+ * Tries to contact server once and perform a stop batch operation
  */
 public class SingleServerCloseBatchWorker extends SingleServerGenericPostWorker<CloseBatchMessage> {
 

bulletin-board-client/src/main/java/meerkat/bulletinboard/workers/singleserver/SingleServerGenericPostWorker.java

@@ -1,8 +1,9 @@
 package meerkat.bulletinboard.workers.singleserver;
 
+import com.google.protobuf.BoolValue;
 import meerkat.bulletinboard.SingleServerWorker;
 import meerkat.comm.CommunicationException;
-import meerkat.protobuf.BulletinBoardAPI.BoolMsg;
+import meerkat.protobuf.Comm.*;
 import meerkat.rest.Constants;
 
 import javax.ws.rs.ProcessingException;
@@ -43,8 +44,8 @@ public class SingleServerGenericPostWorker<T> extends SingleServerWorker<T, Bool
 
         try {
 
-            // If a BoolMsg entity is returned: the post was successful
+            // If a BoolValue entity is returned: the post was successful
-            response.readEntity(BoolMsg.class);
+            response.readEntity(BoolValue.class);
             return Boolean.TRUE;
 
         } catch (ProcessingException | IllegalStateException e) {

bulletin-board-client/src/main/java/meerkat/bulletinboard/workers/singleserver/SingleServerReadBatchWorker.java

@@ -1,25 +1,20 @@
 package meerkat.bulletinboard.workers.singleserver;
 
-import meerkat.bulletinboard.CompleteBatch;
 import meerkat.bulletinboard.SingleServerWorker;
 import meerkat.comm.CommunicationException;
 import meerkat.comm.MessageInputStream;
 import meerkat.protobuf.BulletinBoardAPI.*;
 import meerkat.rest.Constants;
 
-import javax.ws.rs.ProcessingException;
 import javax.ws.rs.client.Client;
 import javax.ws.rs.client.Entity;
 import javax.ws.rs.client.WebTarget;
-import javax.ws.rs.core.GenericType;
-import javax.ws.rs.core.Response;
 import java.io.IOException;
 import java.io.InputStream;
 import java.lang.reflect.InvocationTargetException;
 import java.util.List;
 
 import static meerkat.bulletinboard.BulletinBoardConstants.BULLETIN_BOARD_SERVER_PATH;
-import static meerkat.bulletinboard.BulletinBoardConstants.READ_MESSAGES_PATH;
 import static meerkat.bulletinboard.BulletinBoardConstants.READ_BATCH_PATH;
 
 import static meerkat.bulletinboard.BulletinBoardConstants.BATCH_ID_TAG_PREFIX;
@@ -27,7 +22,7 @@ import static meerkat.bulletinboard.BulletinBoardConstants.BATCH_ID_TAG_PREFIX;
 /**
  * Created by Arbel Deutsch Peled on 27-Dec-15.
  */
-public class SingleServerReadBatchWorker extends SingleServerWorker<BatchSpecificationMessage, List<BatchData>> {
+public class SingleServerReadBatchWorker extends SingleServerWorker<BatchSpecificationMessage, List<BatchChunk>> {
 
     public SingleServerReadBatchWorker(String serverAddress, BatchSpecificationMessage payload, int maxRetry) {
         super(serverAddress, payload, maxRetry);
@@ -39,7 +34,7 @@ public class SingleServerReadBatchWorker extends SingleServerWorker<BatchSpecifi
      * @return the complete batch as read from the server
      * @throws CommunicationException if the server's response is invalid
      */
-    public List<BatchData> call() throws CommunicationException{
+    public List<BatchChunk> call() throws CommunicationException{
 
         Client client = clientLocal.get();
 
@@ -50,11 +45,11 @@ public class SingleServerReadBatchWorker extends SingleServerWorker<BatchSpecifi
         webTarget = client.target(serverAddress).path(BULLETIN_BOARD_SERVER_PATH).path(READ_BATCH_PATH);
         InputStream in = webTarget.request(Constants.MEDIATYPE_PROTOBUF).post(Entity.entity(payload, Constants.MEDIATYPE_PROTOBUF), InputStream.class);
 
-        MessageInputStream<BatchData> inputStream = null;
+        MessageInputStream<BatchChunk> inputStream = null;
 
         try {
 
-            inputStream = MessageInputStream.MessageInputStreamFactory.createMessageInputStream(in, BatchData.class);
+            inputStream = MessageInputStream.MessageInputStreamFactory.createMessageInputStream(in, BatchChunk.class);
 
             return inputStream.asList();
 

bulletin-board-client/src/test/java/meerkat/bulletinboard/GenericBulletinBoardClientTester.java

@@ -8,7 +8,6 @@ import meerkat.crypto.concrete.ECDSASignature;
 import meerkat.protobuf.BulletinBoardAPI.*;
 import meerkat.protobuf.Crypto;
 import meerkat.util.BulletinBoardMessageComparator;
-import meerkat.util.BulletinBoardMessageGenerator;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -266,11 +265,11 @@ public class GenericBulletinBoardClientTester {
 
         for (int i = 0 ; i < length ; i++){
 
-            BatchData batchData = BatchData.newBuilder()
+            BatchChunk batchChunk = BatchChunk.newBuilder()
                     .setData(ByteString.copyFrom(randomByteArray(i)))
                     .build();
 
-            completeBatch.appendBatchData(batchData);
+            completeBatch.appendBatchData(batchChunk);
 
         }
 
@@ -508,7 +507,7 @@ public class GenericBulletinBoardClientTester {
                                 .build())
                         .build();
 
-        // Try to close the (unopened) batch;
+        // Try to stop the (unopened) batch;
 
         bulletinBoardClient.closeBatch(closeBatchMessage, failPostCallback);
 

bulletin-board-server/src/main/java/meerkat/bulletinboard/sqlserver/BulletinBoardSQLServer.java

@@ -1,5 +1,7 @@
 package meerkat.bulletinboard.sqlserver;
 
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
 import java.sql.*;
 import java.util.*;
 
@@ -8,13 +10,12 @@ import com.google.protobuf.*;
 import com.google.protobuf.Timestamp;
 import meerkat.bulletinboard.*;
 import meerkat.bulletinboard.sqlserver.mappers.*;
-import static meerkat.bulletinboard.BulletinBoardConstants.*;
 
 import meerkat.comm.CommunicationException;
 
+import meerkat.comm.MessageInputStream;
 import meerkat.comm.MessageOutputStream;
 import meerkat.crypto.DigitalSignature;
-import meerkat.crypto.concrete.ECDSASignature;
 import meerkat.crypto.concrete.SHA256Digest;
 
 import meerkat.protobuf.BulletinBoardAPI.*;
@@ -127,7 +128,17 @@ public class BulletinBoardSQLServer implements DeletableBulletinBoardServer{
 					new int[] {Types.BLOB, Types.INTEGER}
 			),
 
+			CHECK_BATCH_OPEN(
+					new String[] {"SignerId", "BatchId"},
+					new int[] {Types.BLOB, Types.INTEGER}
+			),
+
 			GET_BATCH_MESSAGE_DATA(
+					new String[] {"MsgId", "StartPosition"},
+					new int[] {Types.BLOB, Types.INTEGER}
+			),
+
+			GET_BATCH_MESSAGE_DATA_BY_IDS(
 					new String[] {"SignerId", "BatchId", "StartPosition"},
 					new int[] {Types.BLOB, Types.INTEGER, Types.INTEGER}
 			),
@@ -150,6 +161,16 @@ public class BulletinBoardSQLServer implements DeletableBulletinBoardServer{
 			REMOVE_BATCH_TAGS(
 					new String[] {"SignerId", "BatchId"},
 					new int[] {Types.BLOB, Types.INTEGER}
+			),
+
+			REMOVE_BATCH_IDS(
+					new String[] {"SignerId", "BatchId"},
+					new int[] {Types.BLOB, Types.INTEGER}
+			),
+
+			ADD_ENTRY_NUM_TO_BATCH(
+					new String[] {"SignerId", "BatchId", "EntryNum"},
+					new int[] {Types.BLOB, Types.INTEGER, Types.INTEGER}
 			);
 
 			private String[] paramNames;
@@ -365,7 +386,6 @@ public class BulletinBoardSQLServer implements DeletableBulletinBoardServer{
 		// TODO write signature reading part.
 		
 		digest = new GenericBulletinBoardDigest(new SHA256Digest());
-		signer = new GenericBatchDigitalSignature(new ECDSASignature());
 
 		jdbcTemplate = new NamedParameterJdbcTemplate(sqlQueryProvider.getDataSource());
 
@@ -411,12 +431,12 @@ public class BulletinBoardSQLServer implements DeletableBulletinBoardServer{
 	}
 	
 	/**
-	 * This procedure is used to convert a boolean to a BoolMsg.
+	 * This procedure is used to convert a boolean to a BoolValue.
 	 * @param b is the boolean to convert.
 	 * @return a ProtoBuf message with boolean payload.
 	 */
-	private BoolMsg boolToBoolMsg(boolean b){
+	private BoolValue boolToBoolValue(boolean b){
-		return BoolMsg.newBuilder()
+		return BoolValue.newBuilder()
 			.setValue(b)
 			.build();
 	}
@@ -425,14 +445,17 @@ public class BulletinBoardSQLServer implements DeletableBulletinBoardServer{
 	/**
 	 * This method posts a messages to the server
 	 * @param msg is the message to post
-	 * @param checkSignature decides whether ot not the method should check the signature before it posts the message
+	 * @param precalculatedMsgID is an optional precalculated message ID
-	 * @return TRUE if the post is successful and FALSE otherwise
+	 *              It is used when the message is the stub of a batch message
+	 *              In this case the validity of the signature is not checked either
+	 * @return -1 if the message is not verified
+	 * 			The entry number of the message if the message is posted
 	 * @throws CommunicationException
      */
-	public BoolMsg postMessage(BulletinBoardMessage msg, boolean checkSignature) throws CommunicationException{
+	private long postMessage(BulletinBoardMessage msg, byte[] precalculatedMsgID) throws CommunicationException{
 
-		if (checkSignature && !verifyMessage(msg)) {
+		if (precalculatedMsgID != null && !verifyMessage(msg)) {
-			return boolToBoolMsg(false);
+			return -1;
 		}
 
 		String sql;
@@ -447,12 +470,16 @@ public class BulletinBoardSQLServer implements DeletableBulletinBoardServer{
 		List<Signature> signatureList;
 		Signature[] signatures;
 
-		// Calculate message ID (depending only on the the unsigned message)
 
-		digest.reset();
+		if (precalculatedMsgID != null){
-		digest.update(msg.getMsg());
+			msgID = precalculatedMsgID;
+		} else{
+			// Calculate message ID (depending only on the the unsigned message)
+			digest.reset();
+			digest.update(msg.getMsg());
 
-		msgID = digest.digest();
+			msgID = digest.digest();
+		}
 
 		// Add message to table if needed and store entry number of message.
 
@@ -530,17 +557,24 @@ public class BulletinBoardSQLServer implements DeletableBulletinBoardServer{
 
 		jdbcTemplate.batchUpdate(sql,namedParameterArray);
 
-		return boolToBoolMsg(true);
+		return entryNum;
 
 	}
 
 	@Override
-	public BoolMsg postMessage(BulletinBoardMessage msg) throws CommunicationException {
+	public BoolValue postMessage(BulletinBoardMessage msg) throws CommunicationException {
-		return postMessage(msg, true);	// Perform a post and check the signature for authenticity
+
+		// Perform a post, calculate the message ID and check the signature for authenticity
+		if (postMessage(msg, null) != -1){
+			return BoolValue.newBuilder().setValue(true).build();	// Message was posted
+		}
+
+		return BoolValue.newBuilder().setValue(false).build();	// Message was not posted
+
 	}
 
 	@Override
-	public BoolMsg deleteMessage(MessageID msgID) throws CommunicationException {
+	public BoolValue deleteMessage(MessageID msgID) throws CommunicationException {
 
 		String sql = sqlQueryProvider.getSQLString(QueryType.DELETE_MSG_BY_ID);
 		Map namedParameters = new HashMap();
@@ -551,12 +585,12 @@ public class BulletinBoardSQLServer implements DeletableBulletinBoardServer{
 
 		//TODO: Log
 
-		return BoolMsg.newBuilder().setValue(affectedRows > 0).build();
+		return BoolValue.newBuilder().setValue(affectedRows > 0).build();
 
 	}
 
 	@Override
-	public BoolMsg deleteMessage(long entryNum) throws CommunicationException {
+	public BoolValue deleteMessage(long entryNum) throws CommunicationException {
 
 		String sql = sqlQueryProvider.getSQLString(QueryType.DELETE_MSG_BY_ENTRY);
 		Map namedParameters = new HashMap();
@@ -567,7 +601,7 @@ public class BulletinBoardSQLServer implements DeletableBulletinBoardServer{
 
 		//TODO: Log
 
-		return BoolMsg.newBuilder().setValue(affectedRows > 0).build();
+		return BoolValue.newBuilder().setValue(affectedRows > 0).build();
 
 	}
 
@@ -653,6 +687,32 @@ public class BulletinBoardSQLServer implements DeletableBulletinBoardServer{
 
 	}
 
+	/**
+	 * Private implementation of the message reader for returning result as a list
+	 * @param filterList is a filter list that defines which messages the client is interested in
+	 * @return the requested list of messages
+	 */
+	private List<BulletinBoardMessage> readMessages(MessageFilterList filterList) throws CommunicationException {
+
+		try {
+
+			ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+
+			readMessages(filterList, new MessageOutputStream<BulletinBoardMessage>(outputStream));
+
+			MessageInputStream<BulletinBoardMessage> inputStream =
+					MessageInputStream.MessageInputStreamFactory.createMessageInputStream(new ByteArrayInputStream(
+									outputStream.toByteArray()),
+							BulletinBoardMessage.class);
+
+			return inputStream.asList();
+
+		} catch (Exception e) {
+			throw new CommunicationException(e.getCause() + " " + e.getMessage());
+		}
+
+	}
+
 
 	@Override
 	public void readMessages(MessageFilterList filterList, MessageOutputStream<BulletinBoardMessage> out) throws CommunicationException {
@@ -678,7 +738,7 @@ public class BulletinBoardSQLServer implements DeletableBulletinBoardServer{
 	}
 
 	@Override
-	public IntMsg getMessageCount(MessageFilterList filterList) throws CommunicationException {
+	public Int32Value getMessageCount(MessageFilterList filterList) throws CommunicationException {
 
 		BulletinBoardMessageList.Builder resultListBuilder = BulletinBoardMessageList.newBuilder();
 
@@ -697,57 +757,62 @@ public class BulletinBoardSQLServer implements DeletableBulletinBoardServer{
 		// Run query and stream the output using a MessageCallbackHandler
 
 		List<Long> count = jdbcTemplate.query(sqlBuilder.toString(), sqlAndParameters.parameters, new LongMapper());
-		return IntMsg.newBuilder().setValue(count.get(0).intValue()).build();
+		return Int32Value.newBuilder().setValue(count.get(0).intValue()).build();
 
 	}
 
 
-	/**
-	 * This method returns a string representation of the tag associated with a batch ID
-	 * @param batchId is the given batch ID
-	 * @return the String representation of the tag
-     */
-	private String batchIdToTag(int batchId) {
-		return BATCH_ID_TAG_PREFIX + Integer.toString(batchId);
-	}
-
-
 	/**
 	 * This method checks if a specified batch exists and is already closed
-	 * @param signerId is the ID of the publisher of the batch
+	 * @param msgID is the unique ID of the batch message
-	 * @param batchId is the unique (per signer) batch ID
      * @return TRUE if the batch is closed and FALSE if it is still open or doesn't exist at all
      */
-	private boolean isBatchClosed(ByteString signerId, int batchId) throws CommunicationException {
+	private boolean isBatchClosed(MessageID msgID) throws CommunicationException {
 
 		MessageFilterList filterList = MessageFilterList.newBuilder()
 				.addFilter(MessageFilter.newBuilder()
-						.setType(FilterType.SIGNER_ID)
+						.setType(FilterType.MSG_ID)
-						.setId(signerId)
+						.setId(msgID.getID())
-						.build())
-				.addFilter(MessageFilter.newBuilder()
-						.setType(FilterType.TAG)
-						.setTag(BATCH_TAG)
-						.build())
-				.addFilter(MessageFilter.newBuilder()
-						.setType(FilterType.TAG)
-						.setTag(batchIdToTag(batchId))
 						.build())
 				.build();
 
-		int count = getMessageCount(filterList).getValue();
 
-		return count > 0;
+		List<BulletinBoardMessage> messages = readMessages(filterList);
+
+		if (messages.size() <= 0){
+			return false;
+		}
+
+		return messages.get(0).getMsg().getIsStub();
 
 	}
 
+	/**
+	 * This method checks if a specified batch exists and is still open
+	 * @param signerId is the signer ID
+	 * @param batchId is the batch ID
+	 * @return TRUE if the batch is closed and FALSE if it is still open or doesn't exist at all
+	 */
+	private boolean isBatchOpen(ByteString signerId, int batchId) throws CommunicationException {
+
+		String sql = sqlQueryProvider.getSQLString(QueryType.CHECK_BATCH_OPEN);
+		MapSqlParameterSource namedParameters = new MapSqlParameterSource();
+
+		namedParameters.addValue(QueryType.CHECK_BATCH_OPEN.getParamName(0),signerId.toByteArray());
+		namedParameters.addValue(QueryType.CHECK_BATCH_OPEN.getParamName(1),batchId);
+
+		List<Long> result = jdbcTemplate.query(sql, namedParameters, new LongMapper());
+
+		return (result.size() > 0 && result.get(0) > 0);
+
+	}
 
 	@Override
-	public BoolMsg beginBatch(BeginBatchMessage message) throws CommunicationException {
+	public BoolValue beginBatch(BeginBatchMessage message) throws CommunicationException {
 
-		// Check if batch is closed
+		// Check if batch is already open
-		if (isBatchClosed(message.getSignerId(), message.getBatchId())) {
+		if (isBatchOpen(message.getSignerId(), message.getBatchId())) {
-			return BoolMsg.newBuilder().setValue(false).build();
+			return BoolValue.newBuilder().setValue(false).build();
 		}
 
 		// Store tags
@@ -760,17 +825,17 @@ public class BulletinBoardSQLServer implements DeletableBulletinBoardServer{
 
 		jdbcTemplate.update(sql,namedParameters);
 
-		return BoolMsg.newBuilder().setValue(true).build();
+		return BoolValue.newBuilder().setValue(true).build();
 
 	}
 
 
 	@Override
-	public BoolMsg postBatchMessage(BatchMessage batchMessage) throws CommunicationException{
+	public BoolValue postBatchMessage(BatchMessage batchMessage) throws CommunicationException{
 
-		// Check if batch is closed
+		// Make sure batch is open
-		if (isBatchClosed(batchMessage.getSignerId(), batchMessage.getBatchId())) {
+		if (!isBatchOpen(batchMessage.getSignerId(), batchMessage.getBatchId())) {
-			return BoolMsg.newBuilder().setValue(false).build();
+			return BoolValue.newBuilder().setValue(false).build();
 		}
 
 		// Add data
@@ -784,19 +849,17 @@ public class BulletinBoardSQLServer implements DeletableBulletinBoardServer{
 
 		jdbcTemplate.update(sql, namedParameters);
 
-		return BoolMsg.newBuilder().setValue(true).build();
+		return BoolValue.newBuilder().setValue(true).build();
 
 	}
 
 
 	@Override
-	public BoolMsg closeBatchMessage(CloseBatchMessage message) throws CommunicationException {
+	public BoolValue closeBatch(CloseBatchMessage message) throws CommunicationException {
 
-		ByteString signerId = message.getSig().getSignerId();
+		ByteString signerId = message.getSig(0).getSignerId();
 		int batchId = message.getBatchId();
 
-		KeyHolder keyHolder = new GeneratedKeyHolder();
-
 		// Check batch size
 
 		String sql = sqlQueryProvider.getSQLString(QueryType.CHECK_BATCH_LENGTH);
@@ -809,10 +872,10 @@ public class BulletinBoardSQLServer implements DeletableBulletinBoardServer{
 		List<Long> lengthResult = jdbcTemplate.query(sql, namedParameters, new LongMapper());
 
 		if (lengthResult.get(0) != message.getBatchLength()) {
-			return BoolMsg.newBuilder().setValue(false).build();
+			return BoolValue.newBuilder().setValue(false).build();
 		}
 
-		// Get Tags and add them to CompleteBatch
+		// Get Tags and add them to BulletinBoardMessage
 
 		sql = sqlQueryProvider.getSQLString(QueryType.GET_BATCH_TAGS);
 		namedParameters = new MapSqlParameterSource();
@@ -823,73 +886,89 @@ public class BulletinBoardSQLServer implements DeletableBulletinBoardServer{
 		List<BeginBatchMessage> beginBatchMessages = jdbcTemplate.query(sql, namedParameters, new BeginBatchMessageMapper());
 
 		if (beginBatchMessages == null || beginBatchMessages.size() <= 0 || beginBatchMessages.get(0) == null) {
-			return BoolMsg.newBuilder().setValue(false).build();
+			return BoolValue.newBuilder().setValue(false).build();
 		}
 
 		UnsignedBulletinBoardMessage unsignedMessage = UnsignedBulletinBoardMessage.newBuilder()
 				.addAllTag(beginBatchMessages.get(0).getTagList())
-				.addTag(BATCH_TAG)
-				.addTag(batchIdToTag(batchId))
 				.setTimestamp(message.getTimestamp())
+				.setIsStub(true)
 				.build();
 
-		// Add actual batch data to CompleteBatch
+		// Digest the data
 
-		sql = sqlQueryProvider.getSQLString(QueryType.GET_BATCH_MESSAGE_DATA);
+		digest.reset();
+		digest.update(unsignedMessage);
+
+		sql = sqlQueryProvider.getSQLString(QueryType.GET_BATCH_MESSAGE_DATA_BY_IDS);
 		namedParameters = new MapSqlParameterSource();
 
-		namedParameters.addValue(QueryType.GET_BATCH_MESSAGE_DATA.getParamName(0),signerId.toByteArray());
+		namedParameters.addValue(QueryType.GET_BATCH_MESSAGE_DATA_BY_IDS.getParamName(0),signerId.toByteArray());
-		namedParameters.addValue(QueryType.GET_BATCH_MESSAGE_DATA.getParamName(1),batchId);
+		namedParameters.addValue(QueryType.GET_BATCH_MESSAGE_DATA_BY_IDS.getParamName(1),batchId);
-		namedParameters.addValue(QueryType.GET_BATCH_MESSAGE_DATA.getParamName(2),0); // Read from the beginning
+		namedParameters.addValue(QueryType.GET_BATCH_MESSAGE_DATA_BY_IDS.getParamName(2),0); // Read from the beginning
+		jdbcTemplate.query(sql, namedParameters, new BatchDataDigestHandler(digest));
 
-		//TODO: Verification
+		byte[] msgID = digest.digest();
-		// Will need to use the following to carry out the signature calculation:
+
-//		jdbcTemplate.query(sql, namedParameters, new BatchDataMapper());
+		//TODO: Signature verification
 
 		// Create Bulletin Board message
 		BulletinBoardMessage bulletinBoardMessage = BulletinBoardMessage.newBuilder()
 				.setMsg(unsignedMessage)
-				.addSig(message.getSig())
+				.addAllSig(message.getSigList())
 				.build();
 
-		// Post message without checking signature validity
+		// Post message with pre-calculated ID and without checking signature validity
-		postMessage(bulletinBoardMessage, false);
+		long entryNum = postMessage(bulletinBoardMessage, msgID);
+
+		// Remove signer ID and batch ID from batch data table
+		// This allows reuse of the batch ID in subsequent batches
+
+		sql = sqlQueryProvider.getSQLString(QueryType.REMOVE_BATCH_IDS);
+
+		namedParameters = new MapSqlParameterSource();
+
+		namedParameters.addValue(QueryType.REMOVE_BATCH_IDS.getParamName(0), signerId.toByteArray());
+		namedParameters.addValue(QueryType.REMOVE_BATCH_IDS.getParamName(1), batchId);
+
+		jdbcTemplate.update(sql, namedParameters);
 
 		// Remove tags from temporary table
 		sql = sqlQueryProvider.getSQLString(QueryType.REMOVE_BATCH_TAGS);
-		namedParameters = new MapSqlParameterSource();
 
-		namedParameters.addValue(QueryType.REMOVE_BATCH_TAGS.getParamName(0), signerId.toByteArray());
+		jdbcTemplate.update(sql, namedParameters);
-		namedParameters.addValue(QueryType.REMOVE_BATCH_TAGS.getParamName(1), batchId);
+
+		// Add entry num to tag data table
+		sql = sqlQueryProvider.getSQLString(QueryType.ADD_ENTRY_NUM_TO_BATCH);
+		namedParameters.addValue(QueryType.ADD_ENTRY_NUM_TO_BATCH.getParamName(2), entryNum);
 
 		jdbcTemplate.update(sql, namedParameters);
 
 		// Return TRUE
 
-		return BoolMsg.newBuilder().setValue(true).build();
+		return BoolValue.newBuilder().setValue(true).build();
+
 	}
 
 
 	@Override
-	public void readBatch(BatchSpecificationMessage message, MessageOutputStream<BatchData> out) throws CommunicationException, IllegalArgumentException{
+	public void readBatch(BatchQuery batchQuery, MessageOutputStream<BatchChunk> out) throws CommunicationException, IllegalArgumentException{
 
 		// Check that batch is closed
-		if (!isBatchClosed(message.getSignerId(), message.getBatchId())) {
+		if (!isBatchClosed(batchQuery.getMsgID())) {
 			throw new IllegalArgumentException("No such batch");
 		}
 
 		String sql = sqlQueryProvider.getSQLString(QueryType.GET_BATCH_MESSAGE_DATA);
 		MapSqlParameterSource namedParameters = new MapSqlParameterSource();
 
-		namedParameters.addValue(QueryType.GET_BATCH_MESSAGE_DATA.getParamName(0),message.getSignerId().toByteArray());
+		namedParameters.addValue(QueryType.GET_BATCH_MESSAGE_DATA.getParamName(0),batchQuery.getMsgID().getID().toByteArray());
-		namedParameters.addValue(QueryType.GET_BATCH_MESSAGE_DATA.getParamName(1),message.getBatchId());
+		namedParameters.addValue(QueryType.GET_BATCH_MESSAGE_DATA.getParamName(1),batchQuery.getStartPosition());
-		namedParameters.addValue(QueryType.GET_BATCH_MESSAGE_DATA.getParamName(2),message.getStartPosition());
 
 		jdbcTemplate.query(sql, namedParameters, new BatchDataCallbackHandler(out));
 
 	}
 
-
 	/**
 	 * Finds the entry number of the last entry in the database
 	 * @return the entry number, or -1 if no entries are found

bulletin-board-server/src/main/java/meerkat/bulletinboard/sqlserver/H2QueryProvider.java

@@ -2,11 +2,7 @@ package meerkat.bulletinboard.sqlserver;
 
 import meerkat.protobuf.BulletinBoardAPI.FilterType;
 import org.apache.commons.dbcp2.BasicDataSource;
-import org.h2.jdbcx.JdbcDataSource;
-import javax.naming.Context;
-import javax.naming.InitialContext;
 
-import javax.naming.NamingException;
 import javax.sql.DataSource;
 import java.text.MessageFormat;
 import java.util.LinkedList;
@@ -112,11 +108,20 @@ public class H2QueryProvider implements BulletinBoardSQLServer.SQLQueryProvider
             case GET_BATCH_MESSAGE_DATA:
                 return MessageFormat.format(
                         "SELECT Data FROM BatchTable"
-                                + " WHERE SignerId = :{0} AND BatchId = :{1} AND SerialNum >= :{2}"
+                                + " INNER JOIN MsgTable ON MsgTable.EntryNum = BatchTable.EntryNum"
-                                + " ORDER BY SerialNum ASC",
+                                + " WHERE MsgTable.MsgId = :{0} AND BatchTable.SerialNum >= :{1}"
+                                + " ORDER BY BatchTable.SerialNum ASC",
                         QueryType.GET_BATCH_MESSAGE_DATA.getParamName(0),
-                        QueryType.GET_BATCH_MESSAGE_DATA.getParamName(1),
+                        QueryType.GET_BATCH_MESSAGE_DATA.getParamName(1));
-                        QueryType.GET_BATCH_MESSAGE_DATA.getParamName(2));
+
+            case GET_BATCH_MESSAGE_DATA_BY_IDS:
+                return MessageFormat.format(
+                        "SELECT Data FROM BatchTable"
+                                + " WHERE SignerId = :{0} AND BatchId = :{1} AND SerialNum >= :{2}"
+                                + " ORDER BY BatchTable.SerialNum ASC",
+                        QueryType.GET_BATCH_MESSAGE_DATA_BY_IDS.getParamName(0),
+                        QueryType.GET_BATCH_MESSAGE_DATA_BY_IDS.getParamName(1),
+                        QueryType.GET_BATCH_MESSAGE_DATA_BY_IDS.getParamName(2));
 
             case INSERT_BATCH_DATA:
                 return MessageFormat.format(
@@ -134,9 +139,16 @@ public class H2QueryProvider implements BulletinBoardSQLServer.SQLQueryProvider
                         QueryType.CHECK_BATCH_LENGTH.getParamName(0),
                         QueryType.CHECK_BATCH_LENGTH.getParamName(1));
 
+            case CHECK_BATCH_OPEN:
+                return MessageFormat.format(
+                        "SELECT COUNT(SignerId) AS signCount FROM BatchTagTable"
+                                + " WHERE SignerId = :{0} AND BatchId = :{1}",
+                        QueryType.CHECK_BATCH_OPEN.getParamName(0),
+                        QueryType.CHECK_BATCH_OPEN.getParamName(1));
+
             case STORE_BATCH_TAGS:
                 return MessageFormat.format(
-                        "INSERT INTO BatchTagTable (SignerId, BatchId, TagId) VALUES (:{0}, :{1}, :{2})",
+                        "INSERT INTO BatchTagTable (SignerId, BatchId, Tags) VALUES (:{0}, :{1}, :{2})",
                         QueryType.STORE_BATCH_TAGS.getParamName(0),
                         QueryType.STORE_BATCH_TAGS.getParamName(1),
                         QueryType.STORE_BATCH_TAGS.getParamName(2));
@@ -153,6 +165,20 @@ public class H2QueryProvider implements BulletinBoardSQLServer.SQLQueryProvider
                         QueryType.REMOVE_BATCH_TAGS.getParamName(0),
                         QueryType.REMOVE_BATCH_TAGS.getParamName(1));
 
+            case REMOVE_BATCH_IDS:
+                return MessageFormat.format(
+                        "UPDATE BatchTable Set (SignerId, BatchId) = (NULL, NULL)" +
+                                " WHERE SignerId = :{0} AND BatchId = :{1}",
+                        QueryType.REMOVE_BATCH_IDS.getParamName(0),
+                        QueryType.REMOVE_BATCH_IDS.getParamName(1));
+
+            case ADD_ENTRY_NUM_TO_BATCH:
+                return MessageFormat.format(
+                        "UPDATE BatchTable SET EntryNum = :{2} WHERE SignerId = :{0} AND BatchId = :{1}",
+                        QueryType.ADD_ENTRY_NUM_TO_BATCH.getParamName(0),
+                        QueryType.ADD_ENTRY_NUM_TO_BATCH.getParamName(1),
+                        QueryType.ADD_ENTRY_NUM_TO_BATCH.getParamName(2));
+
             default:
                 throw new IllegalArgumentException("Cannot serve a query of type " + queryType);
         }
@@ -255,12 +281,12 @@ public class H2QueryProvider implements BulletinBoardSQLServer.SQLQueryProvider
         list.add("CREATE INDEX IF NOT EXISTS SignerIndex ON SignatureTable(SignerId)");
         list.add("CREATE UNIQUE INDEX IF NOT EXISTS SignatureIndex ON SignatureTable(SignerId, EntryNum)");
 
-        list.add("CREATE TABLE IF NOT EXISTS BatchTable (SignerId TINYBLOB, BatchId INT, SerialNum INT, Data BLOB,"
+        list.add("CREATE TABLE IF NOT EXISTS BatchTable (EntryNum INT, SignerId TINYBLOB, BatchId INT, SerialNum INT, Data BLOB,"
                 + " UNIQUE(SignerId, BatchId, SerialNum))");
+        list.add("CREATE INDEX IF NOT EXISTS BatchDataIndex ON BatchTable(EntryNum, SerialNum)");
 
         list.add("CREATE TABLE IF NOT EXISTS BatchTagTable (SignerId TINYBLOB, BatchId INT, Tags BLOB)");
-
+        list.add("CREATE UNIQUE INDEX IF NOT EXISTS BatchTagIndex ON BatchTagTable(SignerId, BatchId)");
-        list.add("CREATE UNIQUE INDEX IF NOT EXISTS BatchIndex ON BatchTagTable(SignerId, BatchId)");
 
         // This is used to create a simple table with one entry.
         // It is used for implementing a workaround for the missing INSERT IGNORE syntax
@@ -275,13 +301,20 @@ public class H2QueryProvider implements BulletinBoardSQLServer.SQLQueryProvider
         List<String> list = new LinkedList<String>();
 
         list.add("DROP TABLE IF EXISTS UtilityTable");
-        list.add("DROP INDEX IF EXISTS BatchIndex");
+
+        list.add("DROP INDEX IF EXISTS BatchTagIndex");
         list.add("DROP TABLE IF EXISTS BatchTagTable");
+
+        list.add("DROP INDEX IF EXISTS BatchDataIndex");
         list.add("DROP TABLE IF EXISTS BatchTable");
-        list.add("DROP INDEX IF EXISTS SignerIdIndex");
+
         list.add("DROP TABLE IF EXISTS MsgTagTable");
+
+        list.add("DROP INDEX IF EXISTS SignerIdIndex");
         list.add("DROP TABLE IF EXISTS SignatureTable");
+
         list.add("DROP TABLE IF EXISTS TagTable");
+
         list.add("DROP TABLE IF EXISTS MsgTable");
 
         return list;

bulletin-board-server/src/main/java/meerkat/bulletinboard/sqlserver/MySQLQueryProvider.java

@@ -111,11 +111,20 @@ public class MySQLQueryProvider implements SQLQueryProvider {
             case GET_BATCH_MESSAGE_DATA:
                 return MessageFormat.format(
                         "SELECT Data FROM BatchTable"
-                        + " WHERE SignerId = :{0} AND BatchId = :{1} AND SerialNum >= :{2}"
+                                + " INNER JOIN MsgTable ON MsgTable.EntryNum = BatchTable.EntryNum"
-                        + " ORDER BY SerialNum ASC",
+                                + " WHERE MsgTable.MsgId = :{0} AND BatchTable.SerialNum >= :{1}"
+                                + " ORDER BY BatchTable.SerialNum ASC",
                         QueryType.GET_BATCH_MESSAGE_DATA.getParamName(0),
-                        QueryType.GET_BATCH_MESSAGE_DATA.getParamName(1),
+                        QueryType.GET_BATCH_MESSAGE_DATA.getParamName(1));
-                        QueryType.GET_BATCH_MESSAGE_DATA.getParamName(2));
+
+            case GET_BATCH_MESSAGE_DATA_BY_IDS:
+                return MessageFormat.format(
+                        "SELECT Data FROM BatchTable"
+                                + " WHERE SignerId = :{0} AND BatchId = :{1} AND SerialNum >= :{2}"
+                                + " ORDER BY BatchTable.SerialNum ASC",
+                        QueryType.GET_BATCH_MESSAGE_DATA_BY_IDS.getParamName(0),
+                        QueryType.GET_BATCH_MESSAGE_DATA_BY_IDS.getParamName(1),
+                        QueryType.GET_BATCH_MESSAGE_DATA_BY_IDS.getParamName(2));
 
             case INSERT_BATCH_DATA:
                 return MessageFormat.format(
@@ -133,18 +142,23 @@ public class MySQLQueryProvider implements SQLQueryProvider {
                         QueryType.CHECK_BATCH_LENGTH.getParamName(0),
                         QueryType.CHECK_BATCH_LENGTH.getParamName(1));
 
-            case CONNECT_BATCH_TAG:
+            case CHECK_BATCH_OPEN:
                 return MessageFormat.format(
-                        "INSERT INTO BatchTagTable (SignerId, BatchId, TagId) SELECT :{0}, :{1}, TagId FROM TagTable"
+                        "SELECT COUNT(Tags) AS signCount FROM BatchTagTable"
-                        + " WHERE Tag = :{2}",
+                                + " WHERE SignerId = :{0} AND BatchId = :{1}",
-                        QueryType.CONNECT_BATCH_TAG.getParamName(0),
+                        QueryType.CHECK_BATCH_OPEN.getParamName(0),
-                        QueryType.CONNECT_BATCH_TAG.getParamName(1),
+                        QueryType.CHECK_BATCH_OPEN.getParamName(1));
-                        QueryType.CONNECT_BATCH_TAG.getParamName(2));
+
+            case STORE_BATCH_TAGS:
+                return MessageFormat.format(
+                        "INSERT INTO BatchTagTable (SignerId, BatchId, Tags) VALUES (:{0}, :{1}, :{2})",
+                        QueryType.STORE_BATCH_TAGS.getParamName(0),
+                        QueryType.STORE_BATCH_TAGS.getParamName(1),
+                        QueryType.STORE_BATCH_TAGS.getParamName(2));
 
             case GET_BATCH_TAGS:
                 return MessageFormat.format(
-                        "SELECT Tag FROM TagTable INNER JOIN BatchTagTable ON TagTable.TagId = BatchTagTable.TagId"
+                        "SELECT Tags FROM BatchTagTable WHERE SignerId = :{0} AND BatchId = :{1}",
-                        + " WHERE SignerId = :{0} AND BatchId = :{1} ORDER BY Tag ASC",
                         QueryType.GET_BATCH_TAGS.getParamName(0),
                         QueryType.GET_BATCH_TAGS.getParamName(1));
 
@@ -154,6 +168,20 @@ public class MySQLQueryProvider implements SQLQueryProvider {
                         QueryType.REMOVE_BATCH_TAGS.getParamName(0),
                         QueryType.REMOVE_BATCH_TAGS.getParamName(1));
 
+            case REMOVE_BATCH_IDS:
+                return MessageFormat.format(
+                        "UPDATE BatchTable Set SignerId = NULL, BatchId = NULL" +
+                                " WHERE SignerId = :{0} AND BatchId = :{1}",
+                        QueryType.REMOVE_BATCH_IDS.getParamName(0),
+                        QueryType.REMOVE_BATCH_IDS.getParamName(1));
+
+            case ADD_ENTRY_NUM_TO_BATCH:
+                return MessageFormat.format(
+                        "UPDATE BatchTable SET EntryNum = :{2} WHERE SignerId = :{0} AND BatchId = :{1}",
+                        QueryType.ADD_ENTRY_NUM_TO_BATCH.getParamName(0),
+                        QueryType.ADD_ENTRY_NUM_TO_BATCH.getParamName(1),
+                        QueryType.ADD_ENTRY_NUM_TO_BATCH.getParamName(2));
+
            default:
                throw new IllegalArgumentException("Cannot serve a query of type " + queryType);
         }
@@ -256,11 +284,11 @@ public class MySQLQueryProvider implements SQLQueryProvider {
                 + " INDEX(SignerId(32)), CONSTRAINT Unique_Signature UNIQUE(SignerId(32), EntryNum),"
                 + " CONSTRAINT FOREIGN KEY (EntryNum) REFERENCES MsgTable(EntryNum))");
 
-        list.add("CREATE TABLE IF NOT EXISTS BatchTable (SignerId TINYBLOB, BatchId INT, SerialNum INT, Data BLOB,"
+        list.add("CREATE TABLE IF NOT EXISTS BatchTable (EntryNum INT, SignerId TINYBLOB, BatchId INT, SerialNum INT, Data BLOB,"
                 + " CONSTRAINT Unique_Batch UNIQUE(SignerId(32), BatchId, SerialNum))");
 
-        list.add("CREATE TABLE IF NOT EXISTS BatchTagTable (SignerId TINYBLOB, BatchId INT, TagId INT,"
+        list.add("CREATE TABLE IF NOT EXISTS BatchTagTable (SignerId TINYBLOB, BatchId INT, Tags BLOB,"
-                + " INDEX(SignerId(32), BatchId), CONSTRAINT FOREIGN KEY (TagId) REFERENCES TagTable(TagId))");
+                + " INDEX(SignerId(32), BatchId))");
 
         return list;
     }
@@ -278,4 +306,4 @@ public class MySQLQueryProvider implements SQLQueryProvider {
 
         return list;
     }
-}
+}

bulletin-board-server/src/main/java/meerkat/bulletinboard/sqlserver/SQLiteQueryProvider.java

@@ -74,11 +74,20 @@ public class SQLiteQueryProvider implements BulletinBoardSQLServer.SQLQueryProvi
             case GET_BATCH_MESSAGE_DATA:
                 return MessageFormat.format(
                         "SELECT Data FROM BatchTable"
-                                + " WHERE SignerId = :{0} AND BatchId = :{1} AND SerialNum >= :{2}"
+                                + " INNER JOIN MsgTable ON MsgTable.EntryNum = BatchTable.EntryNum"
-                                + " ORDER BY SerialNum ASC",
+                                + " WHERE MsgTable.MsgId = :{0} AND BatchTable.SerialNum >= :{1}"
+                                + " ORDER BY BatchTable.SerialNum ASC",
                         QueryType.GET_BATCH_MESSAGE_DATA.getParamName(0),
-                        QueryType.GET_BATCH_MESSAGE_DATA.getParamName(1),
+                        QueryType.GET_BATCH_MESSAGE_DATA.getParamName(1));
-                        QueryType.GET_BATCH_MESSAGE_DATA.getParamName(2));
+
+            case GET_BATCH_MESSAGE_DATA_BY_IDS:
+                return MessageFormat.format(
+                        "SELECT Data FROM BatchTable"
+                                + " WHERE SignerId = :{0} AND BatchId = :{1} AND SerialNum >= :{2}"
+                                + " ORDER BY BatchTable.SerialNum ASC",
+                        QueryType.GET_BATCH_MESSAGE_DATA_BY_IDS.getParamName(0),
+                        QueryType.GET_BATCH_MESSAGE_DATA_BY_IDS.getParamName(1),
+                        QueryType.GET_BATCH_MESSAGE_DATA_BY_IDS.getParamName(2));
 
             case INSERT_BATCH_DATA:
                 return MessageFormat.format(
@@ -96,13 +105,19 @@ public class SQLiteQueryProvider implements BulletinBoardSQLServer.SQLQueryProvi
                         QueryType.CHECK_BATCH_LENGTH.getParamName(0),
                         QueryType.CHECK_BATCH_LENGTH.getParamName(1));
 
-            case CONNECT_BATCH_TAG:
+            case CHECK_BATCH_OPEN:
                 return MessageFormat.format(
-                        "INSERT INTO BatchTagTable (SignerId, BatchId, TagId) SELECT :{0}, :{1}, TagId FROM TagTable"
+                        "SELECT COUNT(Tags) AS signCount FROM BatchTagTable"
-                                + " WHERE Tag = :{2}",
+                                + " WHERE SignerId = :{0} AND BatchId = :{1}",
-                        QueryType.CONNECT_BATCH_TAG.getParamName(0),
+                        QueryType.CHECK_BATCH_OPEN.getParamName(0),
-                        QueryType.CONNECT_BATCH_TAG.getParamName(1),
+                        QueryType.CHECK_BATCH_OPEN.getParamName(1));
-                        QueryType.CONNECT_BATCH_TAG.getParamName(2));
+
+            case STORE_BATCH_TAGS:
+                return MessageFormat.format(
+                        "INSERT INTO BatchTagTable (SignerId, BatchId, Tags) VALUES (:{0}, :{1}, :{2})",
+                        QueryType.STORE_BATCH_TAGS.getParamName(0),
+                        QueryType.STORE_BATCH_TAGS.getParamName(1),
+                        QueryType.STORE_BATCH_TAGS.getParamName(2));
 
             case GET_BATCH_TAGS:
                 return MessageFormat.format(
@@ -117,6 +132,20 @@ public class SQLiteQueryProvider implements BulletinBoardSQLServer.SQLQueryProvi
                         QueryType.REMOVE_BATCH_TAGS.getParamName(0),
                         QueryType.REMOVE_BATCH_TAGS.getParamName(1));
 
+            case REMOVE_BATCH_IDS:
+                return MessageFormat.format(
+                        "UPDATE BatchTable Set (SignerId, BatchId) = (NULL, NULL)" +
+                                " WHERE SignerId = :{0} AND BatchId = :{1}",
+                        QueryType.REMOVE_BATCH_IDS.getParamName(0),
+                        QueryType.REMOVE_BATCH_IDS.getParamName(1));
+
+            case ADD_ENTRY_NUM_TO_BATCH:
+                return MessageFormat.format(
+                        "UPDATE BatchTable SET EntryNum = :{2} WHERE SignerId = :{0} AND BatchId = :{1}",
+                        QueryType.ADD_ENTRY_NUM_TO_BATCH.getParamName(0),
+                        QueryType.ADD_ENTRY_NUM_TO_BATCH.getParamName(1),
+                        QueryType.ADD_ENTRY_NUM_TO_BATCH.getParamName(2));
+
            default:
                throw new IllegalArgumentException("Cannot serve a query of type " + queryType);
         }

bulletin-board-server/src/main/java/meerkat/bulletinboard/sqlserver/mappers/BatchDataCallbackHandler.java

@@ -1,10 +1,8 @@
 package meerkat.bulletinboard.sqlserver.mappers;
 
-import com.google.protobuf.InvalidProtocolBufferException;
 import meerkat.comm.MessageOutputStream;
-import meerkat.protobuf.BulletinBoardAPI.BatchData;
+import meerkat.protobuf.BulletinBoardAPI.BatchChunk;
 import org.springframework.jdbc.core.RowCallbackHandler;
-import org.springframework.jdbc.core.RowMapper;
 
 import java.io.IOException;
 import java.sql.ResultSet;
@@ -15,16 +13,16 @@ import java.sql.SQLException;
  */
 public class BatchDataCallbackHandler implements RowCallbackHandler {
 
-    private final MessageOutputStream<BatchData> out;
+    private final MessageOutputStream<BatchChunk> out;
 
-    public BatchDataCallbackHandler(MessageOutputStream<BatchData> out) {
+    public BatchDataCallbackHandler(MessageOutputStream<BatchChunk> out) {
         this.out = out;
     }
 
     @Override
     public void processRow(ResultSet rs) throws SQLException {
         try {
-            out.writeMessage(BatchData.parseFrom(rs.getBytes(1)));
+            out.writeMessage(BatchChunk.parseFrom(rs.getBytes(1)));
         } catch (IOException e) {
             //TODO: Log
         }

bulletin-board-server/src/main/java/meerkat/bulletinboard/sqlserver/mappers/BatchDataDigestHandler.java

@@ -0,0 +1,31 @@
+package meerkat.bulletinboard.sqlserver.mappers;
+
+import meerkat.bulletinboard.BulletinBoardDigest;
+import meerkat.protobuf.BulletinBoardAPI.BatchChunk;
+import org.springframework.jdbc.core.RowCallbackHandler;
+
+import java.io.IOException;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+/**
+ * Created by Arbel Deutsch Peled on 19-Dec-15.
+ */
+public class BatchDataDigestHandler implements RowCallbackHandler {
+
+    private final BulletinBoardDigest digest;
+
+    public BatchDataDigestHandler(BulletinBoardDigest digest) {
+        this.digest = digest;
+    }
+
+    @Override
+    public void processRow(ResultSet rs) throws SQLException {
+        try {
+            BatchChunk batchChunk = BatchChunk.parseFrom(rs.getBytes(1));
+            digest.update(batchChunk.getData().toByteArray());
+        } catch (IOException e) {
+            //TODO: Log
+        }
+    }
+}

bulletin-board-server/src/main/java/meerkat/bulletinboard/sqlserver/mappers/BatchDataMapper.java

@@ -1,26 +0,0 @@
-package meerkat.bulletinboard.sqlserver.mappers;
-
-import com.google.protobuf.ByteString;
-import com.google.protobuf.InvalidProtocolBufferException;
-import meerkat.protobuf.BulletinBoardAPI.BatchData;
-import org.springframework.jdbc.core.RowMapper;
-
-import java.sql.ResultSet;
-import java.sql.SQLException;
-
-/**
- * Created by Arbel Deutsch Peled on 19-Dec-15.
- */
-public class BatchDataMapper implements RowMapper<BatchData> {
-
-    @Override
-    public BatchData mapRow(ResultSet rs, int rowNum) throws SQLException {
-
-        try {
-            return BatchData.parseFrom(rs.getBytes(1));
-        } catch (InvalidProtocolBufferException e) {
-            return BatchData.getDefaultInstance();
-        }
-
-    }
-}

bulletin-board-server/src/main/java/meerkat/bulletinboard/webapp/BulletinBoardWebApp.java

@@ -8,6 +8,8 @@ import javax.ws.rs.core.Context;
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.StreamingOutput;
 
+import com.google.protobuf.BoolValue;
+import com.google.protobuf.Int32Value;
 import meerkat.bulletinboard.BulletinBoardServer;
 import meerkat.bulletinboard.sqlserver.BulletinBoardSQLServer;
 import meerkat.bulletinboard.sqlserver.H2QueryProvider;
@@ -86,7 +88,7 @@ public class BulletinBoardWebApp implements BulletinBoardServer, ServletContextL
 	@Consumes(MEDIATYPE_PROTOBUF)
 	@Produces(MEDIATYPE_PROTOBUF)
 	@Override
-	public BoolMsg postMessage(BulletinBoardMessage msg) throws CommunicationException {
+	public BoolValue postMessage(BulletinBoardMessage msg) throws CommunicationException {
 		init();
 		return bulletinBoard.postMessage(msg);
 	}
@@ -102,7 +104,7 @@ public class BulletinBoardWebApp implements BulletinBoardServer, ServletContextL
 	@Consumes(MEDIATYPE_PROTOBUF)
 	@Produces(MEDIATYPE_PROTOBUF)
 	@Override
-	public IntMsg getMessageCount(MessageFilterList filterList) throws CommunicationException {
+	public Int32Value getMessageCount(MessageFilterList filterList) throws CommunicationException {
 		init();
 		return bulletinBoard.getMessageCount(filterList);
 	}
@@ -140,7 +142,7 @@ public class BulletinBoardWebApp implements BulletinBoardServer, ServletContextL
 	@Consumes(MEDIATYPE_PROTOBUF)
 	@Produces(MEDIATYPE_PROTOBUF)
 	@Override
-	public BoolMsg beginBatch(BeginBatchMessage message) {
+	public BoolValue beginBatch(BeginBatchMessage message) {
 		try {
 			init();
 			return bulletinBoard.beginBatch(message);
@@ -155,7 +157,7 @@ public class BulletinBoardWebApp implements BulletinBoardServer, ServletContextL
 	@Consumes(MEDIATYPE_PROTOBUF)
 	@Produces(MEDIATYPE_PROTOBUF)
 	@Override
-	public BoolMsg postBatchMessage(BatchMessage batchMessage) {
+	public BoolValue postBatchMessage(BatchMessage batchMessage) {
 		try {
 			init();
 			return bulletinBoard.postBatchMessage(batchMessage);
@@ -170,10 +172,10 @@ public class BulletinBoardWebApp implements BulletinBoardServer, ServletContextL
 	@Consumes(MEDIATYPE_PROTOBUF)
 	@Produces(MEDIATYPE_PROTOBUF)
 	@Override
-	public BoolMsg closeBatchMessage(CloseBatchMessage message) {
+	public BoolValue closeBatch(CloseBatchMessage message) {
 		try {
 			init();
-			return bulletinBoard.closeBatchMessage(message);
+			return bulletinBoard.closeBatch(message);
 		} catch (CommunicationException e) {
 			System.err.println(e.getMessage());
 			return null;
@@ -182,10 +184,10 @@ public class BulletinBoardWebApp implements BulletinBoardServer, ServletContextL
 
 
 	@Override
-	public void readBatch(BatchSpecificationMessage message, MessageOutputStream<BatchData> out) {
+	public void readBatch(BatchQuery batchQuery, MessageOutputStream<BatchChunk> out) throws CommunicationException, IllegalArgumentException {
 		try {
 			init();
-			bulletinBoard.readBatch(message, out);
+			bulletinBoard.readBatch(batchQuery, out);
 		} catch (CommunicationException | IllegalArgumentException e) {
 			System.err.println(e.getMessage());
 		}
@@ -212,17 +214,17 @@ public class BulletinBoardWebApp implements BulletinBoardServer, ServletContextL
 	/**
 	 * Wrapper for the readBatch method which streams the output into the response
 	 */
-	public StreamingOutput readBatch(final BatchSpecificationMessage message) {
+	public StreamingOutput readBatch(final BatchQuery batchQuery) {
 
 		return new StreamingOutput() {
 
 			@Override
 			public void write(OutputStream output) throws IOException, WebApplicationException {
-				MessageOutputStream<BatchData> out = new MessageOutputStream<>(output);
+				MessageOutputStream<BatchChunk> out = new MessageOutputStream<>(output);
 
 				try {
 					init();
-					bulletinBoard.readBatch(message, out);
+					bulletinBoard.readBatch(batchQuery, out);
 				} catch (CommunicationException e) {
 					//TODO: Log
 					out.writeMessage(null);
@@ -270,4 +272,4 @@ public class BulletinBoardWebApp implements BulletinBoardServer, ServletContextL
 		close();
 	}
 	
-}
+}

bulletin-board-server/src/test/java/meerkat/bulletinboard/BulletinBoardSQLServerIntegrationTest.java

@@ -1,6 +1,7 @@
 package meerkat.bulletinboard;
 
 
+import com.google.protobuf.BoolValue;
 import com.google.protobuf.ByteString;
 import com.google.protobuf.TextFormat;
 
@@ -8,6 +9,7 @@ import com.google.protobuf.Timestamp;
 import meerkat.comm.MessageInputStream;
 import meerkat.protobuf.Crypto.*;
 import meerkat.protobuf.BulletinBoardAPI.*;
+import meerkat.protobuf.Comm.*;
 import static meerkat.bulletinboard.BulletinBoardConstants.*;
 import meerkat.rest.Constants;
 import meerkat.rest.ProtobufMessageBodyReader;
@@ -20,7 +22,6 @@ import javax.ws.rs.client.Client;
 import javax.ws.rs.client.ClientBuilder;
 import javax.ws.rs.client.Entity;
 import javax.ws.rs.client.WebTarget;
-import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Response;
 import java.io.InputStream;
 import java.util.List;
@@ -61,7 +62,7 @@ public class BulletinBoardSQLServerIntegrationTest {
 
         WebTarget webTarget;
         Response response;
-        BoolMsg bool;
+        BoolValue bool;
         
         BulletinBoardMessage msg;
         
@@ -95,7 +96,7 @@ public class BulletinBoardSQLServerIntegrationTest {
 
         response = webTarget.request(Constants.MEDIATYPE_PROTOBUF).post(Entity.entity(msg, Constants.MEDIATYPE_PROTOBUF));
         System.err.println(response);
-        bool = response.readEntity(BoolMsg.class);
+        bool = response.readEntity(BoolValue.class);
     	assert bool.getValue();
         
     	msg = BulletinBoardMessage.newBuilder()
@@ -114,7 +115,7 @@ public class BulletinBoardSQLServerIntegrationTest {
     	
     	response = webTarget.request(Constants.MEDIATYPE_PROTOBUF).post(Entity.entity(msg, Constants.MEDIATYPE_PROTOBUF));
         System.err.println(response);
-        bool = response.readEntity(BoolMsg.class);
+        bool = response.readEntity(BoolValue.class);
     	assert bool.getValue();
     	
     	// Test reading mechanism

bulletin-board-server/src/test/java/meerkat/bulletinboard/GenericBulletinBoardServerTest.java

@@ -17,6 +17,7 @@ import java.security.UnrecoverableKeyException;
 import java.security.cert.CertificateException;
 import java.util.*;
 
+import com.google.protobuf.BoolValue;
 import com.google.protobuf.ByteString;
 
 import com.google.protobuf.Timestamp;
@@ -24,12 +25,12 @@ import meerkat.comm.CommunicationException;
 import meerkat.comm.MessageInputStream;
 import meerkat.comm.MessageOutputStream;
 import meerkat.comm.MessageInputStream.MessageInputStreamFactory;
-import meerkat.crypto.Digest;
 import meerkat.crypto.concrete.ECDSASignature;
 import meerkat.crypto.concrete.SHA256Digest;
 import meerkat.protobuf.BulletinBoardAPI.*;
+import meerkat.util.BulletinBoardMessageComparator;
 import meerkat.util.BulletinBoardMessageGenerator;
-import org.h2.util.DateTimeUtils;
+import meerkat.util.BulletinBoardUtils;
 
 import static org.junit.Assert.*;
 import static org.hamcrest.CoreMatchers.*;
@@ -38,7 +39,7 @@ import static org.hamcrest.MatcherAssert.assertThat;
 public class GenericBulletinBoardServerTest {
 
 	protected BulletinBoardServer bulletinBoardServer;
-	private GenericBatchDigitalSignature[] signers;
+	private GenericBulletinBoardSignature[] signers;
 	private ByteString[] signerIDs;
 	
 	private Random random;
@@ -58,24 +59,18 @@ public class GenericBulletinBoardServerTest {
 	private String[] tags;
 	private byte[][] data;
 
-	private List<CompleteBatch> completeBatches;
+	private List<BulletinBoardMessage> batches;
 
 	private final ThreadMXBean threadBean = ManagementFactory.getThreadMXBean(); // Used to time the tests
 
 	private BulletinBoardMessageGenerator bulletinBoardMessageGenerator;
 
-	private Digest digest;
+	private BulletinBoardDigest digest;
+
+	private BulletinBoardMessageComparator comparator;
 
 	/**
 	 * @param bulletinBoardServer is an initialized server.
-	 * @throws InstantiationException
-	 * @throws IllegalAccessException
-	 * @throws CertificateException
-	 * @throws KeyStoreException
-	 * @throws NoSuchAlgorithmException
-	 * @throws IOException
-	 * @throws UnrecoverableKeyException
-	 * @throws CommunicationException
 	 */
 	public void init(BulletinBoardServer bulletinBoardServer) {
 
@@ -84,10 +79,10 @@ public class GenericBulletinBoardServerTest {
 
 		this.bulletinBoardServer = bulletinBoardServer;
 		
-		signers = new GenericBatchDigitalSignature[2];
+		signers = new GenericBulletinBoardSignature[2];
 		signerIDs = new ByteString[signers.length];
-        signers[0] = new GenericBatchDigitalSignature(new ECDSASignature());
+        signers[0] = new GenericBulletinBoardSignature(new ECDSASignature());
-        signers[1] = new GenericBatchDigitalSignature(new ECDSASignature());
+        signers[1] = new GenericBulletinBoardSignature(new ECDSASignature());
 		
 		InputStream keyStream = getClass().getResourceAsStream(KEYFILE_EXAMPLE);
         char[] password = KEYFILE_PASSWORD1.toCharArray();
@@ -133,7 +128,9 @@ public class GenericBulletinBoardServerTest {
         random = new Random(0);
 		bulletinBoardMessageGenerator = new BulletinBoardMessageGenerator(random);
 
-		digest = new SHA256Digest();
+		digest = new GenericBulletinBoardDigest(new SHA256Digest());
+
+		comparator = new BulletinBoardMessageComparator();
 
 		long end = threadBean.getCurrentThreadCpuTime();
 		System.err.println("Finished initializing GenericBulletinBoardServerTest");
@@ -141,7 +138,7 @@ public class GenericBulletinBoardServerTest {
 
 		// Initialize Batch variables
 
-		completeBatches = new ArrayList<CompleteBatch>(10);
+		batches = new ArrayList<>(10);
 
 	}
 	
@@ -445,73 +442,94 @@ public class GenericBulletinBoardServerTest {
 
 	}
 
-	/**
-	 * Tests that posting a message before opening a batch does not work
-	 * @throws CommunicationException
-     */
-	public void testBatchPostAfterClose() throws CommunicationException, SignatureException {
 
-		final int BATCH_ID = 100;
+	private void postAsBatch(BulletinBoardMessage message, ByteString signerId, int batchId, int chunkSize, boolean close) throws CommunicationException {
 
-		CompleteBatch completeBatch = new CompleteBatch(Timestamp.newBuilder()
+		List<BatchChunk> batchChunks = BulletinBoardUtils.breakToBatch(message, chunkSize);
-				.setSeconds(978325)
+		BeginBatchMessage beginBatchMessage = BulletinBoardUtils.generateBeginBatchMessage(signerId, batchId, message);
-				.setNanos(8097234)
-				.build());
-		BoolMsg result;
 
-		// Create data
+		BoolValue result;
-
-		completeBatch.setBeginBatchMessage(BeginBatchMessage.newBuilder()
-				.setSignerId(signerIDs[1])
-				.setBatchId(BATCH_ID)
-				.addTag("Test")
-				.build());
-
-		BatchData batchData = BatchData.newBuilder()
-				.setData(ByteString.copyFrom((new byte[] {1,2,3,4})))
-				.build();
-
-		completeBatch.appendBatchData(batchData);
-
-		signers[1].updateContent(completeBatch);
-
-		completeBatch.setSignature(signers[1].sign());
 
 		// Begin batch
 
-		result = bulletinBoardServer.beginBatch(completeBatch.getBeginBatchMessage());
+		result = bulletinBoardServer.beginBatch(beginBatchMessage);
 
 		assertThat("Was not able to open batch", result.getValue(), is(true));
 
-		// Post data
-
-		BatchMessage batchMessage = BatchMessage.newBuilder()
-				.setSignerId(signerIDs[1])
-				.setBatchId(BATCH_ID)
-				.setData(batchData)
-				.build();
-
-		result = bulletinBoardServer.postBatchMessage(batchMessage);
-
-		assertThat("Was not able to post batch message", result.getValue(), is(true));
-
-		// Close batch
-
-		result = bulletinBoardServer.closeBatchMessage(completeBatch.getCloseBatchMessage());
-
-		assertThat("Was not able to close batch", result.getValue(), is(true));
-
 		// Attempt to open batch again
 
-		result = bulletinBoardServer.beginBatch(completeBatch.getBeginBatchMessage());
+		result = bulletinBoardServer.beginBatch(beginBatchMessage);
 
 		assertThat("Was able to open a closed batch", result.getValue(), is(false));
 
-		// Attempt to add batch data
+		// Post data
 
-		result = bulletinBoardServer.postBatchMessage(batchMessage);
+		BatchMessage batchMessage = BatchMessage.getDefaultInstance();
 
-		assertThat("Was able to change a closed batch", result.getValue(), is(false));
+		for (int i = 0 ; i < batchChunks.size() ; i++){
+
+			batchMessage = BatchMessage.newBuilder()
+					.setSignerId(signerId)
+					.setBatchId(batchId)
+					.setSerialNum(i)
+					.setData(batchChunks.get(i))
+					.build();
+
+			result = bulletinBoardServer.postBatchMessage(batchMessage);
+
+			assertThat("Was not able to post batch message", result.getValue(), is(true));
+
+		}
+
+		// Close batch
+		if (close) {
+
+			CloseBatchMessage closeBatchMessage = BulletinBoardUtils.generateCloseBatchMessage(batchId, batchChunks.size(), message);
+
+			result = bulletinBoardServer.closeBatch(closeBatchMessage);
+
+			assertThat("Was not able to close batch", result.getValue(), is(true));
+
+		}
+
+	}
+
+	/**
+	 * Tests that opening the same batch ID while one is open results in failure
+	 * @throws CommunicationException
+     */
+	public void testReopen() throws CommunicationException, SignatureException {
+
+		// Create data
+		final int BATCH_ID = 100;
+		final int DATA_SIZE = 1;
+		final int CHUNK_SIZE = 1;
+		final int TAG_NUMBER = 1;
+
+		Timestamp timestamp = Timestamp.newBuilder()
+				.setSeconds(141510)
+				.setNanos(48015)
+				.build();
+
+		BulletinBoardMessage batch = bulletinBoardMessageGenerator.generateRandomMessage(signers, timestamp, DATA_SIZE, TAG_NUMBER);
+
+		// Post batch but do not close
+
+		postAsBatch(batch, signerIDs[0], BATCH_ID, CHUNK_SIZE, false);
+
+		// Attempt to open batch again
+
+		BoolValue result;
+
+		result = bulletinBoardServer.beginBatch(BulletinBoardUtils.generateBeginBatchMessage(signerIDs[0], BATCH_ID, batch));
+
+		assertThat("Was able to open a closed batch", result.getValue(), is(false));
+
+		// Close batch
+
+		result = bulletinBoardServer.closeBatch(BulletinBoardUtils.generateCloseBatchMessage(BATCH_ID, DATA_SIZE / CHUNK_SIZE, batch));
+
+		assertThat("Was not able to close batch", result.getValue(), is(true));
 
 	}
 
@@ -521,110 +539,79 @@ public class GenericBulletinBoardServerTest {
 	 */
 	public void testPostBatch() throws CommunicationException, SignatureException {
 
-		CompleteBatch completeBatch = new CompleteBatch(Timestamp.newBuilder()
+		// Create data
-				.setSeconds(12345)
+		final int BATCH_ID = 200;
-				.setNanos(1111)
+		final int DATA_SIZE = 10000;
-				.build());
+		final int CHUNK_SIZE = 100;
-		int currentBatch = completeBatches.size();
+		final int TAG_NUMBER = 10;
 
-		BoolMsg result;
+		Timestamp timestamp = Timestamp.newBuilder()
+				.setSeconds(5235000)
+				.setNanos(32541)
+				.build();
 
-		// Define batch data
+		BulletinBoardMessage batch = bulletinBoardMessageGenerator.generateRandomMessage(signers, timestamp, DATA_SIZE, TAG_NUMBER);
 
-		String[] tempBatchTags = new String[]{randomString(),randomString(),randomString()};
+		// Post batch
-		byte[][] tempBatchData = new byte[Math.abs(randomByte())][];
 
-		for (int i = 0 ; i < tempBatchData.length ; i++) {
+		postAsBatch(batch, signerIDs[0], BATCH_ID, CHUNK_SIZE, true);
-
-			tempBatchData[i] = new byte[Math.abs(randomByte())];
-
-			for (int j = 0; j < tempBatchData[i].length; j++) {
-				tempBatchData[i][j] = randomByte();
-			}
-
-		}
-
-		// Begin batch
-
-		completeBatch.setBeginBatchMessage(BeginBatchMessage.newBuilder()
-				.setSignerId(signerIDs[0])
-				.setBatchId(currentBatch)
-				.addAllTag(Arrays.asList(tempBatchTags))
-				.build());
-
-		result = bulletinBoardServer.beginBatch(completeBatch.getBeginBatchMessage());
-
-		assertThat("Could not begin batch " + currentBatch, result.getValue(), is(true));
-
-		// Add batch data and randomize data posting order
-
-		List<Integer> dataOrder = new ArrayList<Integer>(tempBatchData.length);
-		for (int i = 0 ; i < tempBatchData.length ; i++) {
-			dataOrder.add(i);
-			completeBatch.appendBatchData(BatchData.newBuilder()
-					.setData(ByteString.copyFrom(tempBatchData[i]))
-					.build());
-		}
-		Collections.shuffle(dataOrder);
-
-		// Post data
-
-		for (int i = 0 ; i < tempBatchData.length ; i++) {
-
-			int dataIndex = dataOrder.get(i);
-
-			result = bulletinBoardServer.postBatchMessage(BatchMessage.newBuilder()
-					.setSignerId(signerIDs[0])
-					.setBatchId(currentBatch)
-					.setSerialNum(dataIndex)
-					.setData(completeBatch.getBatchDataList().get(dataIndex))
-					.build());
-
-			assertThat("Could not post batch data for batch ID " + currentBatch + " serial number " + dataIndex,
-					result.getValue(), is(true));
-
-		}
-
-		// Close batch
-
-		signers[0].updateContent(completeBatch);
-		completeBatch.setSignature(signers[0].sign());
-
-		result = bulletinBoardServer.closeBatchMessage(completeBatch.getCloseBatchMessage());
-
-		assertThat("Could not close batch " + currentBatch,	result.getValue(), is(true));
 
 		// Update locally stored batches
-		completeBatches.add(completeBatch);
+		batches.add(batch);
 
 	}
 
 	public void testReadBatch() throws CommunicationException {
 
-		for (CompleteBatch completeBatch : completeBatches) {
+		for (BulletinBoardMessage message : batches) {
 
 			try {
 
 				ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
 
-				BatchSpecificationMessage batchSpecificationMessage =
+				digest.update(message);
-						BatchSpecificationMessage.newBuilder()
+
-								.setSignerId(completeBatch.getBeginBatchMessage().getSignerId())
+				MessageID msgId = digest.digestAsMessageID();
-								.setBatchId(completeBatch.getBeginBatchMessage().getBatchId())
+
+				MessageFilterList messageFilterList = MessageFilterList.newBuilder()
+						.addFilter(MessageFilter.newBuilder()
+								.setType(FilterType.MSG_ID)
+								.setId(msgId.getID())
+								.build())
+						.build();
+
+				bulletinBoardServer.readMessages(messageFilterList, new MessageOutputStream<BulletinBoardMessage>(outputStream));
+
+				MessageInputStream<BulletinBoardMessage> messageInputStream =
+						MessageInputStreamFactory.createMessageInputStream(new ByteArrayInputStream(
+										outputStream.toByteArray()),
+								BulletinBoardMessage.class);
+
+				List<BulletinBoardMessage> messageList = messageInputStream.asList();
+
+				assertThat("No stub found for message ID " + msgId.getID().toStringUtf8(), messageList.size() == 1);
+
+				BulletinBoardMessage stub = messageList.get(0);
+
+				BatchQuery batchQuery =
+						BatchQuery.newBuilder()
+								.setMsgID(msgId)
 								.setStartPosition(0)
 								.build();
 
-				bulletinBoardServer.readBatch(batchSpecificationMessage, new MessageOutputStream<BatchData>(outputStream));
+				bulletinBoardServer.readBatch(batchQuery, new MessageOutputStream<BatchChunk>(outputStream));
 
-				MessageInputStream<BatchData> inputStream =
+				MessageInputStream<BatchChunk> batchInputStream =
 						MessageInputStreamFactory.createMessageInputStream(new ByteArrayInputStream(
 								outputStream.toByteArray()),
-								BatchData.class);
+								BatchChunk.class);
 
-				List<BatchData> batchDataList = inputStream.asList();
+				List<BatchChunk> batchChunkList = batchInputStream.asList();
 
-				assertThat("Non-matching batch data for batch " + completeBatch.getBeginBatchMessage().getBatchId(),
+				BulletinBoardMessage retrievedMessage = BulletinBoardUtils.gatherBatch(stub, batchChunkList);
-						completeBatch.getBatchDataList().equals(batchDataList), is(true));
+
+				assertThat("Non-matching batch data for batch " + msgId.getID().toStringUtf8(),
+						comparator.compare(message, retrievedMessage) == 0);
 
 			} catch (IOException | NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
 				assertThat("Error reading batch data list from input stream", false);
@@ -646,7 +633,7 @@ public class GenericBulletinBoardServerTest {
 
 		BulletinBoardMessage newMessage = bulletinBoardMessageGenerator.generateRandomMessage(signers, timestamp, 10, 10);
 
-		BoolMsg result = bulletinBoardServer.postMessage(newMessage);
+		BoolValue result = bulletinBoardServer.postMessage(newMessage);
 		assertThat("Failed to post message to BB Server", result.getValue(), is(true));
 
 		ByteArrayOutputStream outputStream = new ByteArrayOutputStream();

bulletin-board-server/src/test/java/meerkat/bulletinboard/H2BulletinBoardServerTest.java

@@ -7,7 +7,6 @@ import meerkat.comm.CommunicationException;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
-import org.junit.runner.Result;
 
 import java.lang.management.ManagementFactory;
 import java.lang.management.ThreadMXBean;
@@ -108,9 +107,9 @@ public class H2BulletinBoardServerTest {
     }
 
     @Test
-    public void testBatchPostAfterClose() {
+    public void testBatchReopen() {
         try{
-            serverTest.testBatchPostAfterClose();
+            serverTest.testReopen();
         } catch (Exception e) {
             System.err.println(e.getMessage());
             fail(e.getMessage());

bulletin-board-server/src/test/java/meerkat/bulletinboard/MySQLBulletinBoardServerTest.java

@@ -8,13 +8,9 @@ import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 
-import java.io.IOException;
 import java.lang.management.ManagementFactory;
 import java.lang.management.ThreadMXBean;
-import java.lang.reflect.InvocationTargetException;
-import java.security.SignatureException;
 import java.sql.Connection;
-import java.sql.DriverManager;
 import java.sql.SQLException;
 import java.sql.Statement;
 import java.util.List;
@@ -115,9 +111,9 @@ public class MySQLBulletinBoardServerTest {
     }
 
     @Test
-    public void testBatchPostAfterClose() {
+    public void testBatchReopen() {
         try{
-            serverTest.testBatchPostAfterClose();
+            serverTest.testReopen();
         } catch (Exception e) {
             System.err.println(e.getMessage());
             fail(e.getMessage());

distributed-key-generation/build.gradle

@@ -0,0 +1,223 @@
+
+plugins {
+  id "us.kirchmeier.capsule" version "1.0.1"
+  id 'com.google.protobuf' version '0.7.0'
+}
+
+apply plugin: 'java'
+apply plugin: 'eclipse'
+apply plugin: 'idea'
+
+apply plugin: 'maven-publish'
+
+// Uncomment the lines below to define an application
+// (this will also allow you to build a "fatCapsule" which includes
+// the entire application, including all dependencies in a single jar)
+//apply plugin: 'application'
+//mainClassName='your.main.ApplicationClass'
+
+// Is this a snapshot version?
+ext { isSnapshot = false } 
+
+ext {
+        groupId = 'org.factcenter.meerkat'
+        nexusRepository = "https://cs.idc.ac.il/nexus/content/groups/${isSnapshot ? 'unstable' : 'public'}/"
+        
+        // Credentials for IDC nexus repositories (needed only for using unstable repositories and publishing)
+        // Should be set in ${HOME}/.gradle/gradle.properties
+        nexusUser =  project.hasProperty('nexusUser') ? project.property('nexusUser') : ""
+        nexusPassword = project.hasProperty('nexusPassword') ? project.property('nexusPassword') : ""
+}
+
+description = "TODO: Add a description"
+
+// Your project version
+version = "0.0"
+
+version += "${isSnapshot ? '-SNAPSHOT' : ''}"
+
+
+dependencies {
+    // Meerkat common
+    compile project(':meerkat-common')
+
+    // Logging
+    compile 'org.slf4j:slf4j-api:1.7.7'
+    runtime 'ch.qos.logback:logback-classic:1.1.2'
+    runtime 'ch.qos.logback:logback-core:1.1.2'
+
+    // Google protobufs
+    compile 'com.google.protobuf:protobuf-java:3.+'
+
+    // Depend on test resources from meerkat-common
+    testCompile project(path: ':meerkat-common', configuration: 'testOutput')
+
+    testCompile 'junit:junit:4.+'
+
+    runtime 'org.codehaus.groovy:groovy:2.4.+'
+}
+
+
+/*==== You probably don't have to edit below this line =======*/
+
+// Setup test configuration that can appear as a dependency in
+// other subprojects
+configurations {
+    testOutput.extendsFrom (testCompile)
+}
+
+task testJar(type: Jar, dependsOn: testClasses) {
+    classifier = 'tests'
+    from sourceSets.test.output
+}
+
+artifacts {
+    testOutput testJar
+}
+
+// The run task added by the application plugin
+// is also of type JavaExec.
+tasks.withType(JavaExec) {
+    // Assign all Java system properties from
+    // the command line to the JavaExec task.
+    systemProperties System.properties
+}
+
+
+protobuf {
+    // Configure the protoc executable
+    protoc {
+    // Download from repositories
+        artifact = 'com.google.protobuf:protoc:3.+'
+    }
+}
+
+
+idea {
+    module {
+        project.sourceSets.each { sourceSet ->
+
+            def srcDir = "${protobuf.generatedFilesBaseDir}/$sourceSet.name/java"
+
+            println "Adding $srcDir"
+            // add protobuf generated sources to generated source dir.
+            if ("test".equals(sourceSet.name)) {
+                testSourceDirs += file(srcDir)
+            } else {
+                sourceDirs += file(srcDir)
+            }
+            generatedSourceDirs += file(srcDir)
+
+        }
+
+	    // Don't exclude build directory
+	    excludeDirs -= file(buildDir)
+    }
+}
+
+
+/*===================================
+ *        "Fat" Build targets
+ *===================================*/
+
+
+if (project.hasProperty('mainClassName') && (mainClassName != null)) {
+
+    task mavenCapsule(type: MavenCapsule) {
+        description = "Generate a capsule jar that automatically downloads and caches dependencies when run."
+        applicationClass mainClassName
+        destinationDir = buildDir
+    }
+
+    task fatCapsule(type: FatCapsule) {
+        description = "Generate a single capsule jar containing everything. Use -Pfatmain=... to override main class"
+
+        destinationDir = buildDir
+
+        def fatMain = hasProperty('fatmain') ? fatmain : mainClassName
+
+        applicationClass fatMain
+
+        def testJar = hasProperty('test')
+
+        if (hasProperty('fatmain')) {
+            appendix = "fat-${fatMain}"
+        } else {
+            appendix = "fat"
+        }
+
+        if (testJar) {
+            from sourceSets.test.output
+        }
+    }
+}
+
+
+/*===================================
+ *        Repositories
+ *===================================*/
+
+repositories {
+        
+        // Prefer the local nexus repository (it may have 3rd party artifacts not found in mavenCentral)
+        maven { 
+            url nexusRepository
+            
+            if (isSnapshot) {
+                credentials { username 
+                    password 
+
+                    username nexusUser
+                    password nexusPassword 
+                }
+            }
+        }
+
+        // Use local maven repository
+        mavenLocal()
+
+        // Use 'maven central' for other dependencies.
+        mavenCentral()
+}
+
+task "info" << {
+        println "Project: ${project.name}"
+println "Description: ${project.description}"
+        println "--------------------------"
+        println "GroupId: $groupId"
+        println "Version: $version (${isSnapshot ? 'snapshot' : 'release'})"
+        println ""
+}
+info.description 'Print some information about project parameters'
+
+
+/*===================================
+ *        Publishing
+ *===================================*/
+
+publishing {
+    publications {
+        mavenJava(MavenPublication) {
+            groupId project.groupId
+            pom.withXml {
+                asNode().appendNode('description', project.description)
+            }
+            from project.components.java
+
+        }
+    }
+    repositories {
+        maven {
+            url "https://cs.idc.ac.il/nexus/content/repositories/${project.isSnapshot ? 'snapshots' : 'releases'}"
+            credentials { username 
+                password 
+
+                username nexusUser
+                password nexusPassword 
+            }
+        }
+    }
+}
+
+
+

distributed-key-generation/src/main/java/meerkat/crypto/dkg/comm/MessageHandler.java

@@ -0,0 +1,47 @@
+package meerkat.crypto.dkg.comm;
+
+import com.google.protobuf.InvalidProtocolBufferException;
+import meerkat.comm.Channel;
+import meerkat.protobuf.Comm;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Created by Tzlil on 2/14/2016.
+ *
+ * an implementation of ReceiverCallback
+ */
+public abstract class MessageHandler implements Channel.ReceiverCallback {
+    final Logger logger = LoggerFactory.getLogger(getClass());
+
+    /**
+     * fixed value for broadcasting
+     */
+    public static final int BROADCAST = 0;
+
+       /**
+     * Handle a broadcast (or unicast) message.
+     * If the message is invalid, the handler can throw an {@link InvalidProtocolBufferException}, in which
+     * case the message will simply be ignored.
+     * @param envelope
+     */
+    public abstract void handleMessage(Comm.BroadcastMessage envelope) throws InvalidProtocolBufferException;
+
+    /**
+     * Was this broadcastMessage was received by broadcast channel
+     * @param broadcastMessage
+     * @return broadcastMessage user destination == BROADCAST
+     */
+    public boolean isBroadcast(Comm.BroadcastMessage broadcastMessage){
+        return broadcastMessage.getDestination() == BROADCAST;
+    }
+
+    @Override
+    public void receiveMessage(Comm.BroadcastMessage envelope) {
+        try {
+            handleMessage(envelope);
+        } catch (InvalidProtocolBufferException e) {
+            logger.warn("Received invalid protocol buffer from channel", e);
+        }
+    }
+}

distributed-key-generation/src/main/java/meerkat/crypto/dkg/comm/MessageUtils.java

@@ -0,0 +1,36 @@
+package meerkat.crypto.dkg.comm;
+
+import meerkat.protobuf.DKG;
+
+/**
+ * Created by talm on 12/04/16.
+ */
+public class MessageUtils {
+    public static DKG.Payload createMessage(DKG.Payload.Type type) {
+        return DKG.Payload.newBuilder().setType(type).build();
+    }
+
+    public static DKG.Payload createMessage(DKG.Payload.Type type, DKG.ShareMessage share) {
+        return DKG.Payload.newBuilder().setType(type).setShare(share).build();
+    }
+
+    public static DKG.Payload createMessage(DKG.Payload.Type type, DKG.ShareMessage.Builder share) {
+        return DKG.Payload.newBuilder().setType(type).setShare(share).build();
+    }
+
+    public static DKG.Payload createMessage(DKG.Payload.Type type, DKG.IDMessage id) {
+        return DKG.Payload.newBuilder().setType(type).setId(id).build();
+    }
+
+    public static DKG.Payload createMessage(DKG.Payload.Type type, DKG.IDMessage.Builder id) {
+        return DKG.Payload.newBuilder().setType(type).setId(id).build();
+    }
+
+    public static DKG.Payload createMessage(DKG.Payload.Type type, DKG.CommitmentMessage commitment) {
+        return DKG.Payload.newBuilder().setType(type).setCommitment(commitment).build();
+    }
+
+    public static DKG.Payload createMessage(DKG.Payload.Type type, DKG.CommitmentMessage.Builder commitment) {
+        return DKG.Payload.newBuilder().setType(type).setCommitment(commitment).build();
+    }
+}

distributed-key-generation/src/main/java/meerkat/crypto/dkg/feldman/Party.java

@@ -0,0 +1,40 @@
+package meerkat.crypto.dkg.feldman;
+
+import meerkat.crypto.secretsharing.shamir.Polynomial;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+
+/**
+ * Created by Tzlil on 3/14/2016.
+ *
+ * contains all relevant information on specific party during
+ * the run of Joint Feldamn protocol
+ */
+public class Party<T> {
+    public final int id;
+    public Polynomial.Point share;
+    public ArrayList<T> commitments;
+    public boolean doneFlag;
+    public Protocol.ComplaintState[] complaints;
+    public boolean aborted;
+
+    /**
+     *
+     * @param id party identifier - 1 <= id <= n
+     * @param n number of parties in current run protocol
+     * @param t protocol's threshold
+     */
+    public Party(int id, int n, int t) {
+        this.id = id;
+        this.share = null;
+        this.doneFlag = false;
+        this.complaints = new Protocol.ComplaintState[n];
+        Arrays.fill(this.complaints, Protocol.ComplaintState.OK);
+        this.commitments = new ArrayList<T>(t + 1);
+        for (int i = 0; i <= t ; i++){
+            commitments.add(null);
+        }
+        this.aborted = false;
+    }
+}

distributed-key-generation/src/main/java/meerkat/crypto/dkg/feldman/Protocol.java

@@ -0,0 +1,368 @@
+package meerkat.crypto.dkg.feldman;
+
+import meerkat.comm.Channel;
+import meerkat.crypto.secretsharing.feldman.VerifiableSecretSharing;
+import meerkat.crypto.secretsharing.shamir.Polynomial;
+import com.google.protobuf.ByteString;
+import meerkat.protobuf.DKG;
+import org.factcenter.qilin.primitives.Group;
+import org.factcenter.qilin.util.ByteEncoder;
+
+import java.math.BigInteger;
+import java.util.*;
+
+import static meerkat.crypto.dkg.comm.MessageUtils.*;
+
+/**
+ * Created by Tzlil on 3/14/2016.
+ *
+ * an implementation of JointFeldman distributed key generation protocol.
+ *
+ * allows set of n parties to generate random key with threshold t.
+ */
+public class Protocol<T> extends VerifiableSecretSharing<T> {
+    public enum ComplaintState {
+        /**
+         * No complaints, no response required at this point.
+         */
+        OK,
+
+        /**
+         * Party received complaint, waiting for response from party
+         */
+        Waiting,
+
+        /**
+         * Party gave invalid answer to conplaint.
+         */
+        Disqualified,
+
+        /**
+         * Party received complaint, gave valid answer.
+         */
+        NonDisqualified
+    }
+
+    /**
+     * My share id.
+     */
+    protected final int id;
+
+    /**
+     * All parties participating in key generation.
+     * parties[id-1] has my info.
+     */
+    private Party<T>[] parties;
+
+    /**
+     * communication object
+     */
+    protected Channel channel;
+
+    /**
+     * Encode/Decode group elements
+     */
+    protected final ByteEncoder<T> encoder;
+
+    /**
+     * constructor
+     * @param q      a large prime.
+     * @param t      threshold. Any t+1 share holders can recover the secret,
+     *               but any set of at most t share holders cannot
+     * @param n      number of share holders
+     * @param zi      secret, chosen from Zq
+     * @param random use for generate random polynomial
+     * @param group
+     * @param q a large prime dividing group order.
+     * @param g a generator of cyclic group of order q.
+     *          the generated group is a subgroup of the given group.
+     *          it must be chosen such that computing discrete logarithms is hard in this group.
+     * @param encoder Encode/Decode group elements (of type T) to/from byte array
+     */
+    public Protocol(int t, int n, BigInteger zi, Random random, BigInteger q, T g
+            , Group<T> group, int id, ByteEncoder<T> encoder)  {
+        super(t, n, zi, random, q, g,group);
+        this.id = id;
+        this.parties = new Party[n];
+        for (int i = 1; i <= n ; i++){
+            this.parties[i - 1] = new Party(i,n,t);
+        }
+        this.parties[id - 1].share = getShare(id);
+        this.encoder = encoder;
+    }
+
+    /**
+     * setter
+     * @param channel
+     */
+    public void setChannel(Channel channel){
+        this.channel = channel;
+    }
+
+    /**
+     * setter
+     * @param parties
+     */
+    protected void setParties(Party[] parties){
+        this.parties = parties;
+    }
+
+    /**
+     * getter
+     * @return
+     */
+    protected Party[] getParties(){
+        return parties;
+    }
+
+    /**
+     * stage1.1 according to the protocol
+     *  Pi broadcasts Aik for k = 0,...,t.
+     */
+    public void broadcastCommitments(){
+        broadcastCommitments(commitmentsArrayList);
+    }
+
+    /**
+     * pack commitments as messages and broadcast them
+     * @param commitments
+     */
+    public void broadcastCommitments(ArrayList<T> commitments){
+        DKG.CommitmentMessage commitmentMessage;
+        for (int k = 0; k <= t ; k++){
+            commitmentMessage = DKG.CommitmentMessage.newBuilder()
+                    .setCommitment(ByteString.copyFrom(encoder.encode(commitments.get(k))))
+                    .setK(k)
+                    .build();
+            channel.broadcastMessage(createMessage(DKG.Payload.Type.COMMITMENT, commitmentMessage));
+        }
+    }
+
+    /**
+     * Send channel j her secret share (of my polynomial)
+     * @param j
+     */
+    public void sendSecret(int j){
+        ByteString secret = ByteString.copyFrom(getShare(j).y.toByteArray());
+        channel.sendMessage(j, createMessage(DKG.Payload.Type.SHARE,
+                DKG.ShareMessage.newBuilder()
+                        .setI(id)
+                        .setJ(j)
+                        .setShare(secret)
+                        ));
+    }
+
+    /**
+     * stage1.2 according to the protocol
+     *  Pi computes the shares Sij for j = 1,...,n and sends Sij secretly to Pj.
+     */
+    public void sendSecrets(){
+        for (int j = 1; j <= n ; j++){
+            if(j != id){
+                sendSecret(j);
+            }
+        }
+    }
+
+    /**
+     *
+     * @param i
+     * @return computeVerificationValue(j,parties[i - 1].commitments,group) == g ^ parties[i - 1].share mod q
+     */
+    public boolean isValidShare(int i){
+        Party<T> party = parties[i - 1];
+        synchronized (parties[i - 1]) {
+            return isValidShare(party.share, party.commitments, id);
+        }
+    }
+
+    /**
+     * @param share
+     * @param commitments
+     * @param j
+     * @return computeVerificationValue(j,commitments,group) == g ^ secret.y mod q
+     */
+    public boolean isValidShare(Polynomial.Point share, ArrayList<T> commitments, int j){
+        try{
+            T v = computeVerificationValue(j,commitments,group);
+            return group.multiply(g,share.y).equals(v);
+        }
+        catch (NullPointerException e){
+            return false;
+        }
+    }
+
+    /**
+     * stage2 according to the protocol
+     *  Pj verifies all the shares he received (using isValidShare)
+     *  if check fails for an index i, Pj broadcasts a complaint against Pi.
+     */
+    public void broadcastComplaints(){
+        for (int i = 1; i <= n ; i++ ){
+            if(i != id && !isValidShare(i)) {
+                broadcastComplaint(i);
+            }
+        }
+    }
+
+    /**
+     * create a complaint message against i and broadcast it
+     * @param i
+     */
+    private void broadcastComplaint(int i){
+        //message = new Message(Type.Complaint, j)
+        DKG.IDMessage complaint = DKG.IDMessage.newBuilder()
+                .setId(i)
+                .build();
+        channel.broadcastMessage(createMessage(DKG.Payload.Type.COMPLAINT, complaint));
+    }
+
+    /**
+     * create an answer message for j and broadcast it
+     * @param j
+     */
+    public void broadcastComplaintAnswer(int j){
+        channel.broadcastMessage(createMessage(DKG.Payload.Type.ANSWER, DKG.ShareMessage.newBuilder()
+                .setI(id)
+                .setJ(j)
+                .setShare(ByteString.copyFrom(getShare(j).y.toByteArray()))));
+    }
+
+    /**
+     * stage3.1 according to the protocol
+     *   if more than t players complain against a player Pi he is disqualified.
+     */
+    public void answerAllComplainingPlayers(){
+        ComplaintState[] complaints = parties[id - 1].complaints;
+        for (int i = 1; i <= n; i++) {
+            switch (complaints[i - 1]) {
+                case Waiting:
+                    broadcastComplaintAnswer(i);
+                    break;
+                default:
+                    break;
+            }
+        }
+
+    }
+
+    /**
+     * stage3.2 according to the protocol
+     *  if any of the revealed shares fails the verification test, player Pi is disqualified.
+     *  set QUAL to be the set of non-disqualified players.
+     */
+    public Set<Integer> calcQUAL(){
+        Set<Integer> QUAL = new HashSet<Integer>();
+        boolean nonDisqualified;
+        int counter;
+        for (int i = 1; i <= n; i++) {
+            synchronized (parties[i - 1]) {
+                ComplaintState[] complaints = parties[i - 1].complaints;
+                nonDisqualified = true;
+                counter = 0;
+                for (int j = 1; j <= n; j++) {
+                    switch (complaints[j - 1]) {
+                        case OK:
+                            break;
+                        case NonDisqualified:
+                            counter++;
+                            break;
+                        default:
+                            nonDisqualified = false;
+                            break;
+                    }
+                    if (!nonDisqualified)
+                        break;
+                }
+                if (nonDisqualified && counter <= t) {
+                    QUAL.add(i);
+                }
+            }
+        }
+        return QUAL;
+    }
+
+    /**
+     * compute Y, the commitment to the final public key (includes only qualifying set)
+     * stage4.1 according to the protocol
+     *   public value y is computed as y = multiplication of yi mod p for i in QUAL
+     */
+    public T calcY(Set<Integer> QUAL){
+        T y = group.zero();
+        for (int i : QUAL) {
+            synchronized (parties[i - 1]) {
+                y = group.add(y, parties[i - 1].commitments.get(0));
+            }
+        }
+        return y;
+    }
+
+    /**
+     * stage4.2 according to the protocol
+     *  public verification values are computed as Ak = multiplication
+     *  of Aik mod p for i in QUAL for k = 0,...,t
+     */
+    public ArrayList<T> calcCommitments(Set<Integer> QUAL){
+        ArrayList<T> commitments = new ArrayList<T>(t+1);
+        T value;
+        for (int k = 0; k <= t; k++){
+            value = group.zero();
+            for (int i : QUAL) {
+                synchronized (parties[i - 1]) {
+                    value = group.add(value, parties[i - 1].commitments.get(k));
+                }
+            }
+            commitments.add(k,value);
+        }
+        return commitments;
+    }
+
+    /**
+     * stage4.3 according to the protocol
+     *  Pj sets is share of the share as xj = sum of Sij mod q for i in QUAL
+     */
+    public Polynomial.Point calcShare(Set<Integer> QUAL){
+        BigInteger xj = BigInteger.ZERO;
+        for (int i : QUAL) {
+            synchronized (parties[i - 1]) {
+                xj = xj.add(parties[i - 1].share.y);
+            }
+        }
+        return new Polynomial.Point(BigInteger.valueOf(id) , xj.mod(q));
+    }
+
+    /**
+     * decode commitment from arr
+     * @param arr
+     * @return
+     */
+    public T decodeCommitment(byte[] arr){
+        return encoder.decode(arr);
+    }
+
+    /**
+     * getter
+     * @return id
+     */
+    public int getId() {
+        return id;
+    }
+
+    /**
+     * getter
+     * @return channel
+     */
+    public Channel getChannel() {
+        return channel;
+    }
+
+
+    /**
+     * getter
+     * @return encoder
+     */
+    public ByteEncoder<T> getEncoder() {
+        return encoder;
+    }
+
+}

distributed-key-generation/src/main/java/meerkat/crypto/dkg/feldman/User.java

@@ -0,0 +1,588 @@
+package meerkat.crypto.dkg.feldman;
+
+import com.google.protobuf.InvalidProtocolBufferException;
+import com.google.protobuf.TextFormat;
+import meerkat.comm.Channel;
+import meerkat.crypto.dkg.comm.MessageHandler;
+import meerkat.crypto.secretsharing.shamir.Polynomial;
+import com.google.protobuf.ByteString;
+import meerkat.protobuf.Comm;
+import meerkat.protobuf.DKG;
+import org.factcenter.qilin.primitives.Group;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.Set;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingDeque;
+
+import static meerkat.crypto.dkg.comm.MessageUtils.createMessage;
+
+/**
+ * Created by Tzlil on 3/14/2016.
+ *
+ * implementation of joint feldman protocol user.
+ *
+ * according to the protocol, each user run feldman verifiable secret sharing
+ * as a dealer.
+ *
+ * by the end of run(), each party in QUAL has his own share of the generated random key.
+ * this key can be recover by any subset of QUAL of size at least t + 1.
+ */
+public class User<T> implements Runnable {
+    final Logger logger = LoggerFactory.getLogger(getClass());
+
+    /**
+     * joint feldman protocol object
+     */
+    protected final Protocol<T> dkg;
+
+    /**
+     * a generator of cyclic group of order q.
+     *          the generated group is a subgroup of the given group.
+     *          it must be chosen such that computing discrete logarithms is hard in this group.
+     */
+    protected final T g;
+
+    /**
+     * cyclic group contains g.
+     */
+    protected final Group<T> group;
+
+    /**
+     * user id
+     */
+    protected final int id;
+
+    /**
+     * threshold
+     */
+    protected final int t;
+
+    /**
+     * number of shares
+     */
+    protected final int n;
+
+
+    /**
+     * channel object
+     */
+    protected final Channel channel; //
+
+    /**
+     * All parties participating in key generation.
+     * parties[id-1] has my info.
+     */
+    protected final Party[] parties;
+
+    /**
+     * set of all non-disqualified parties
+     */
+    protected Set<Integer> QUAL;
+
+    /**
+     * my own share of the generated random key.
+     */
+    protected Polynomial.Point share;
+
+    /**
+     * public verification values
+     */
+    protected ArrayList<T> commitments;
+
+    /**
+     * public value,
+     * y = g ^ key
+     */
+    protected T y;
+
+    protected BlockingQueue<Comm.BroadcastMessage> receiveQueue;
+
+    /**
+     * constructor
+     * @param dkg joint feldman protocol object
+     * @param channel channel object
+     */
+    public User(Protocol<T> dkg, Channel channel) {
+        this.dkg = dkg;
+
+        this.g = dkg.getGenerator();
+        this.group = dkg.getGroup();
+        this.n = dkg.getN();
+        this.t = dkg.getT();
+        this.id = dkg.getId();
+
+        this.channel = channel;
+        dkg.setChannel(channel);
+        registerReceiverCallback();
+
+        this.parties = dkg.getParties();
+        this.QUAL = null;
+        this.commitments = null;
+        this.share = null;
+        this.y = null;
+
+        this.receiveQueue = new LinkedBlockingDeque<>();
+
+    }
+
+    /**
+     * create MessageHandler and register it as ReceiverCallback
+     */
+    protected void registerReceiverCallback() {
+        channel.registerReceiverCallback(new meerkat.crypto.dkg.comm.MessageHandler() {
+            @Override
+            public void handleMessage(Comm.BroadcastMessage envelope) throws InvalidProtocolBufferException {
+                receiveQueue.add(envelope);
+            }
+        });
+
+//        this.messageHandler = new MessageHandler();
+//        channel.registerReceiverCallback(messageHandler);
+    }
+
+    /**
+     * Wait for at least one message to arrive, then handle any messages currently in the queue
+     */
+    protected void waitAndHandleReceivedMessages()  {
+        Comm.BroadcastMessage msg = null;
+        while (!stop && msg == null) {
+            try {
+                msg = receiveQueue.take();
+            } catch (InterruptedException e) {
+                // Possibly stop
+            }
+        }
+        while (!stop && msg != null) {
+            try {
+                handleMessage(msg);
+            } catch (InvalidProtocolBufferException e) {
+                logger.warn("Received invalid message: {}", TextFormat.printToString(msg));
+            }
+            msg = receiveQueue.poll();
+        }
+    }
+
+    /**
+     * stage1 according to the protocol
+     *  1. Pi broadcasts Aik for k = 0,...,t.
+     *  2. Pi computes the shares Sij for j = 1,...,n and sends Sij secretly to Pj.
+     */
+    protected void stage1() {
+        dkg.broadcastCommitments();
+        dkg.sendSecrets();
+    }
+
+    /**
+     * Check if all shares and commitments have arrived from other parties
+     */
+    protected boolean isStageOneCompleted() {
+        for (int i = 0 ; i < n ; i++) {
+            if (!parties[i].aborted) {
+                if (parties[i].share == null)
+                    return false;
+                for (int k = 0 ; k <=  t ; k++) {
+                    if (parties[i].commitments.get(k) == null)
+                        return false;
+                }
+            }
+        }
+        return true;
+    }
+
+    protected void waitUntilStageOneCompleted() {
+        while (!stop && !isStageOneCompleted())
+            waitAndHandleReceivedMessages();
+    }
+
+    protected  boolean isStageTwoCompleted() {
+        for (int i = 0 ; i < n ; i++) {
+            if (!parties[i].aborted && !parties[i].doneFlag)
+                return false;
+        }
+        return true;
+    }
+
+    /**
+     * stage2 according to the protocol
+     *  Pj verifies all the shares he received
+     *  if check fails for an index i, Pj broadcasts a complaint against Pi.
+     *  Pj broadcasts done message at the end of this stage
+     */
+    protected void stage2() {
+        dkg.broadcastComplaints();
+        //broadcast done message after all complaints
+        channel.broadcastMessage(createMessage(DKG.Payload.Type.DONE));
+    }
+
+    /**
+     * wait until all other parties done complaining by receiving done message
+     */
+    protected void waitUntilStageTwoCompleted(){
+        while (!stop && !isStageTwoCompleted())
+            waitAndHandleReceivedMessages();
+    }
+
+
+    protected boolean haveReceivedAllStage3ComplaintAnswers() {
+        for (int i = 0; i < n; i++) {
+            if (parties[i].aborted)
+                continue;
+            for (int j = 0; j < n; j++) {
+                if (parties[i].complaints[j].equals(Protocol.ComplaintState.Waiting))
+                    return false;
+
+            }
+        }
+        return true;
+    }
+
+    /**
+     * stage3 according to the protocol
+     *  1. if more than t players complain against a player Pi he is disqualified.
+     *     otherwise Pi broadcasts the share Sij for each complaining player Pj.
+     *  2. if any of the revealed shares fails the verification test, player Pi is disqualified.
+     *     set QUAL to be the set of non-disqualified players.
+     */
+    protected void stage3(){
+        dkg.answerAllComplainingPlayers();
+
+        // wait until there is no complaint waiting for answer
+        while (!stop && !haveReceivedAllStage3ComplaintAnswers())
+            waitAndHandleReceivedMessages();
+
+        this.QUAL = dkg.calcQUAL();
+    }
+
+    /**
+     * stage4 according to the protocol
+     *  1. public value y is computed as y = multiplication of yi mod p for i in QUAL
+     *  2. public verification values are computed as Ak = multiplication of Aik mod p for i in QUAL for k = 0,...,t
+     *  3. Pj sets is share of the secret as xj = sum of Sij mod q for i in QUAL
+     */
+    protected void stage4(){
+        this.y = dkg.calcY(QUAL);
+        this.commitments = dkg.calcCommitments(QUAL);
+        this.share = dkg.calcShare(QUAL);
+    }
+
+    @Override
+    public void run() {
+        this.runThread = Thread.currentThread();
+        // For debugging
+        String previousName = runThread.getName();
+        runThread.setName(getClass().getName() +":" + getID());
+
+        try {
+            stage1();
+            waitUntilStageOneCompleted();
+            if (stop) return;
+            stage2();
+            waitUntilStageTwoCompleted();
+            if (stop) return;
+            stage3();
+            if (stop) return;
+            stage4();
+        } finally {
+            runThread.setName(previousName);
+        }
+    }
+
+    /**
+     * current thread in the main loop
+     */
+    protected Thread runThread;
+
+    /**
+     * flag indicates if there was request to stop the current run of the protocol
+     */
+    protected boolean stop = false;
+
+    /**
+     * Request the current run loop to exit gracefully
+     */
+    public void stop() {
+        try {
+            stop = true;
+            runThread.interrupt();
+        }catch (Exception e){
+            //do nothing
+        }
+
+    }
+
+    /**
+     * getter
+     * @return commitments
+     */
+    public ArrayList<T> getCommitments() {
+        return commitments;
+    }
+
+    /**
+     * getter
+     * @return g
+     */
+    public T getGenerator() {
+        return g;
+    }
+
+    /**
+     * getter
+     * @return group
+     */
+    public Group<T> getGroup() {
+        return group;
+    }
+
+    /**
+     * getter
+     * @return share
+     */
+    public Polynomial.Point getShare() {
+        return share;
+    }
+
+    /**
+     * getter
+     * @return id
+     */
+    public int getID() {
+        return id;
+    }
+
+    /**
+     * getter
+     * @return n
+     */
+    public int getN() {
+        return n;
+    }
+
+    /**
+     * getter
+     * @return t
+     */
+    public int getT() {
+        return t;
+    }
+
+    /**
+     * getter
+     * @return y
+     */
+    public T getPublicValue() {
+        return y;
+    }
+
+    /**
+     * getter
+     * @return QUAL
+     */
+    public Set<Integer> getQUAL() {
+        return QUAL;
+    }
+
+    /**
+     * getter
+     * @return channel
+     */
+    public Channel getChannel() {
+        return channel;
+    }
+
+    /**
+     * commitment message is valid if:
+     *  1. it was received in broadcast chanel
+     *  2. the sender didn't sent this commitment before
+     */
+    protected boolean isValidCommitmentMessage(int sender, boolean isBroadcast, DKG.CommitmentMessage commitmentMessage){
+        int i = sender - 1;
+        int k = commitmentMessage.getK();
+        return isBroadcast && parties[i].commitments.get(k) == null;
+    }
+
+    /**
+     * secret message is valid if:
+     *  1. it was received in private chanel
+     *  2. the sender didn't sent secret message before
+     *  3. secret.i == i
+     *  4. secret.j == id
+     */
+    protected boolean isValidSecretMessage(int sender, boolean isBroadcast, DKG.ShareMessage secretMessage){
+        int i = secretMessage.getI();
+        int j = secretMessage.getJ();
+        if(sender != i  || isBroadcast)
+            return false;
+        else
+            return parties[i - 1].share == null && j == id;
+
+    }
+
+    /**
+     * done message is valid if:
+     *  1. it was received in broadcast chanel
+     *  2. the sender didn't sent done message before
+     */
+    protected boolean isValidDoneMessage(int sender, boolean isBroadcast){
+        return isBroadcast && !parties[sender - 1].doneFlag;
+    }
+
+
+    /**
+     * complaint message is valid if:
+     *  1. it was received in broadcast chanel
+     *  2. the sender didn't complained against id before
+     */
+    protected boolean isValidComplaintMessage(int sender, boolean isBroadcast, DKG.IDMessage complaintMessage){
+        int i = sender;
+        int j = complaintMessage.getId();
+
+        assert(i > 0);
+        assert(j > 0);
+        assert(i <= parties.length);
+        assert(j <= parties[i-1].complaints.length);
+
+        return isBroadcast && parties[i - 1].complaints[j - 1].equals( Protocol.ComplaintState.OK);
+    }
+
+    /**
+     * answer message is valid if:
+     *  1. it was received in broadcast chanel
+     *  2. secret.i == i
+     *  3. 1 <= secret.j <= n
+     *  4. it is marked that j complained against i and i didn't received
+     */
+    protected boolean isValidAnswerMessage(int sender, boolean isBroadcast, DKG.ShareMessage secretMessage){
+        int i = secretMessage.getI();
+        int j = secretMessage.getJ();
+        if(sender != i  || !isBroadcast)
+            return false;
+        else
+            return j >= 1 && j <= n && parties[i - 1].complaints[j - 1].equals(Protocol.ComplaintState.Waiting);
+    }
+
+
+    public void handleMessage(Comm.BroadcastMessage envelope) throws InvalidProtocolBufferException {
+        int sender = envelope.getSender();
+        boolean isBroadcast = !envelope.getIsPrivate();
+        DKG.Payload msg = DKG.Payload.parseFrom(envelope.getPayload());
+
+        logger.debug("handling Message: Dst={}, Src={}, [{}]",
+                envelope.getDestination(), envelope.getSender(), TextFormat.printToString(msg));
+
+        switch (msg.getType()) {
+            case COMMITMENT:
+                /**
+                 * saves the commitment
+                 */
+                assert msg.getPayloadDataCase() == DKG.Payload.PayloadDataCase.COMMITMENT;
+                DKG.CommitmentMessage commitmentMessage = msg.getCommitment();
+                if (isValidCommitmentMessage(sender, isBroadcast, commitmentMessage)) {
+                    int i = sender - 1;
+                    int k = commitmentMessage.getK();
+
+                    parties[i].commitments.set(k, extractCommitment(commitmentMessage));
+                }
+                break;
+
+
+            case SHARE:
+                /**
+                 * saves the secret
+                 */
+                assert msg.getPayloadDataCase() == DKG.Payload.PayloadDataCase.SHARE;
+                DKG.ShareMessage secretMessage = msg.getShare();
+                if(isValidSecretMessage(sender,isBroadcast,secretMessage)) {
+                    int i = secretMessage.getI();
+                    Polynomial.Point secret = extractShare(id,secretMessage.getShare());
+                    parties[i - 1].share = secret;
+                }
+                break;
+
+            case DONE:
+
+                /**
+                 * marks that the sender was finished sending all his complaints
+                 */
+                if(isValidDoneMessage(sender,isBroadcast)) {
+                    parties[sender - 1].doneFlag = true;
+                }
+                break;
+
+            case COMPLAINT:
+                /**
+                 * marks that the sender was complained against id
+                 */
+                if (msg.getPayloadDataCase() != DKG.Payload.PayloadDataCase.ID) {
+                    logger.error("User {} Expecting ID message, got from SRC={} msg {}", getID(), envelope.getSender(), TextFormat.printToString(msg));
+                    assert (msg.getPayloadDataCase() == DKG.Payload.PayloadDataCase.ID);
+                }
+
+                DKG.IDMessage complaintMessage = msg.getId();
+                if(isValidComplaintMessage(sender,isBroadcast,complaintMessage)){
+                    int i = sender;
+                    int j = complaintMessage.getId();
+                    parties[j - 1].complaints[i - 1] = Protocol.ComplaintState.Waiting;
+                }
+                break;
+            case ANSWER:
+                /**
+                 * if the secret is valid, marks the complaint as NonDisqualified
+                 * else marks it as Disqualified
+                 * in case that the complainer is id ( j == id ), saves the secret
+                 */
+                assert msg.getPayloadDataCase() == DKG.Payload.PayloadDataCase.SHARE;
+                secretMessage = msg.getShare();
+                if(isValidAnswerMessage(sender,isBroadcast,secretMessage)) {
+                    int i = secretMessage.getI();
+                    int j = secretMessage.getJ();
+                    Polynomial.Point secret = extractShare(j,secretMessage.getShare());
+                    if (dkg.isValidShare(secret, parties[i - 1].commitments, j)) {
+                        parties[i - 1].complaints[j - 1] = Protocol.ComplaintState.NonDisqualified;
+                    } else {
+                        parties[i - 1].complaints[j - 1] = Protocol.ComplaintState.Disqualified;
+                    }
+                    if (j == id) {
+                        parties[i - 1].share = secret;
+                    }
+                }
+                break;
+            case ABORT:
+                /**
+                 * marks that the sender was aborted
+                 */
+                parties[sender - 1].aborted = true;
+                break;
+            default:
+                logger.error("Bad message: SRC={}, DST={}, Payload={}", envelope.getSender(), envelope.getDestination(), TextFormat.printToString(msg));
+                break;
+
+        }
+    }
+
+    /**
+     * extract share value from ByteString
+     * @param i
+     * @param share
+     * @return new Point (i,share)
+     */
+    public Polynomial.Point extractShare(int i, ByteString share){
+        BigInteger x = BigInteger.valueOf(i);
+        BigInteger y = new BigInteger(share.toByteArray());
+        return new Polynomial.Point(x,y);
+    }
+
+    /**
+     *
+     * @param commitmentMessage
+     * @return
+     */
+    public T extractCommitment(DKG.CommitmentMessage commitmentMessage){
+        return dkg.decodeCommitment(commitmentMessage.getCommitment().toByteArray());
+    }
+}

distributed-key-generation/src/main/java/meerkat/crypto/dkg/gjkr/Party.java

@@ -0,0 +1,28 @@
+package meerkat.crypto.dkg.gjkr;
+
+import meerkat.crypto.secretsharing.shamir.Polynomial;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * Created by Tzlil on 3/16/2016.
+ *
+ * an extension of DistributedKeyGenerationParty
+ * contains all relevant information on specific party during
+ * the run of the safe protocol
+ */
+public class Party<T> extends meerkat.crypto.dkg.feldman.Party<T> {
+    public Polynomial.Point shareT;
+    public boolean ysDoneFlag;
+    public ArrayList<T> verifiableValues;
+    public Set<Polynomial.Point> recoverSharesSet;
+    public Party(int id, int n, int t) {
+        super(id, n, t);
+        this.shareT = null;
+        this.ysDoneFlag = false;
+        this.verifiableValues = new ArrayList<T>(this.commitments);
+        this.recoverSharesSet = new HashSet<Polynomial.Point>();
+    }
+}

distributed-key-generation/src/main/java/meerkat/crypto/dkg/gjkr/Protocol.java

@@ -0,0 +1,165 @@
+package meerkat.crypto.dkg.gjkr;
+
+import meerkat.crypto.dkg.comm.MessageUtils;
+import meerkat.crypto.secretsharing.feldman.VerifiableSecretSharing;
+import meerkat.crypto.secretsharing.shamir.Polynomial;
+import com.google.protobuf.ByteString;
+import meerkat.protobuf.DKG;
+import org.factcenter.qilin.primitives.Group;
+import org.factcenter.qilin.util.ByteEncoder;
+
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.Random;
+import java.util.Set;
+
+/**
+ * Created by Tzlil on 3/16/2016.
+ * TODO: comments
+ * TODO: put Channel (ChannelImpl) in constructor
+ */
+public class Protocol<T> extends meerkat.crypto.dkg.feldman.Protocol<T> {
+
+    private VerifiableSecretSharing<T> maskingShares;
+    private final T h;
+    private Party<T>[] parties;
+
+    public Protocol(int t, int n, BigInteger zi, Random random, BigInteger q, T g
+            , T h, Group<T> group, int id, ByteEncoder<T> byteEncoder) {
+        super(t, n, zi, random, q, g, group, id,byteEncoder);
+        this.h = h;
+        BigInteger r = new BigInteger(q.bitLength(),random).mod(q);
+        this.maskingShares = new VerifiableSecretSharing(t,n,r,random,q,h,group);
+        this.parties = new Party[n];
+        for (int i = 1; i <= n ; i++){
+            this.parties[i - 1] = new Party(i,n,t);
+        }
+        this.parties[id - 1].share = getShare(id);
+        this.parties[id - 1].shareT = maskingShares.getShare(id);
+        super.setParties(parties);
+    }
+
+    protected Party[] getParties(){
+        return parties;
+    }
+
+    protected void setParties(Party[] parties) {
+        super.setParties(parties);
+        this.parties = parties;
+    }
+
+
+    @Override
+    public void sendSecret(int j) {
+        Polynomial.Point secret = getShare(j);
+        Polynomial.Point secretT = maskingShares.getShare(j);
+        DKG.ShareMessage doubleSecretMessage = createShareMessage(id,j,secret,secretT);
+        // TODO: Change SHARE to SHARE
+        channel.sendMessage(j, MessageUtils.createMessage(DKG.Payload.Type.SHARE, doubleSecretMessage));
+    }
+
+
+    @Override
+    public boolean isValidShare(int i){
+        Party party = parties[i - 1];
+        return isValidShare(party.share, party.shareT, party.verifiableValues, id);
+    }
+
+    /**
+     * test if share, shareT are valid with respect to verificationValues
+     * @param share
+     * @param shareT
+     * @param verificationValues
+     * @param j
+     * @return computeVerificationValue(j,verificationValues,group) == (g ^ share.y) * (h ^ shareT.y) mod q
+     */
+    public boolean isValidShare(Polynomial.Point share, Polynomial.Point shareT, ArrayList<T> verificationValues, int j){
+        try {
+            T v = computeVerificationValue(j, verificationValues, group);
+            T exp = group.add(group.multiply(g, share.y), group.multiply(h, shareT.y));
+            return exp.equals(v);
+        }
+        catch (NullPointerException e){
+            return false;
+        }
+    }
+
+    /**
+     * create complaint message against i and broadcast it
+     * @param share
+     * @param shareT
+     * @param i
+     */
+    private void broadcastComplaint(Polynomial.Point share, Polynomial.Point shareT, int i){
+        DKG.ShareMessage complaint = createShareMessage(i,id,share,shareT);
+        channel.broadcastMessage(MessageUtils.createMessage(DKG.Payload.Type.COMPLAINT, complaint));
+    }
+
+    /**
+     * stage4.3 according to the protocol
+     *  if check fails for index i, Pj
+     */
+    public void computeAndBroadcastComplaints(Set<Integer> QUAL){
+        Party party;
+        for (int i : QUAL) {
+            party = parties[i - 1];
+            if (i != id) {
+                if (!super.isValidShare(party.share, party.commitments, id)) {
+                    broadcastComplaint(party.share, party.shareT, i);
+                }
+            }
+        }
+    }
+
+    /**
+     * compute verification values and broadcast them
+     * verificationValues[k] = g ^ commitments [k] * h ^ maskingShares.commitments [k]
+     */
+    public void computeAndBroadcastVerificationValues(){
+        ArrayList<T> verificationValues = new ArrayList<T>(t+1);
+        ArrayList<T> hBaseCommitments = maskingShares.getCommitmentsArrayList();
+        for (int k = 0 ; k <= t ; k++){
+            verificationValues.add(k,group.add(commitmentsArrayList.get(k),hBaseCommitments.get(k)));
+        }
+        broadcastCommitments(verificationValues);
+    }
+
+    /**
+     * pack share, shareT i,j to createShareMessage
+     * @param i
+     * @param j
+     * @param share
+     * @param shareT
+     * @return
+     */
+
+    private DKG.ShareMessage createShareMessage(int i, int j, Polynomial.Point share, Polynomial.Point shareT){
+        DKG.ShareMessage ShareMessage = DKG.ShareMessage.newBuilder()
+                .setI(i)
+                .setJ(j)
+                .setShare(ByteString.copyFrom(share.y.toByteArray()))
+                .setShareT(ByteString.copyFrom(shareT.y.toByteArray()))
+                .build();
+        return ShareMessage;
+    }
+
+    @Override
+    public void broadcastComplaintAnswer(int j) {
+        DKG.ShareMessage answer = createShareMessage(id,j,getShare(j)
+                , maskingShares.getShare(j));
+        channel.broadcastMessage(MessageUtils.createMessage(DKG.Payload.Type.ANSWER, answer));
+    }
+
+    public void broadcastAnswer(Polynomial.Point secret, Polynomial.Point secretT, int i){
+        DKG.ShareMessage complaint = createShareMessage(i,id,secret,secretT);
+        channel.broadcastMessage(MessageUtils.createMessage(DKG.Payload.Type.ANSWER,complaint));
+    }
+
+    /**
+     * getter
+     * @return h
+     */
+    public T getH() {
+        return h;
+    }
+}

distributed-key-generation/src/main/java/meerkat/crypto/dkg/gjkr/User.java

@@ -0,0 +1,359 @@
+package meerkat.crypto.dkg.gjkr;
+
+import com.google.protobuf.InvalidProtocolBufferException;
+import meerkat.crypto.utils.Arithmetic;
+import meerkat.crypto.utils.concrete.Fp;
+import meerkat.comm.Channel;
+import meerkat.crypto.secretsharing.shamir.Polynomial;
+import meerkat.crypto.secretsharing.shamir.SecretSharing;
+import meerkat.protobuf.Comm;
+import meerkat.protobuf.DKG;
+
+import java.math.BigInteger;
+import java.util.ArrayList;
+
+import static meerkat.crypto.dkg.comm.MessageUtils.*;
+
+/**
+ * Created by Tzlil on 3/16/2016.
+ * <p/>
+ * implementation of gjkr protocol user.
+ * <p/>
+ * this protocol extends joint Feldman protocol by splitting the protocol to commitment stage (stages 1,2,3)
+ * and revealing stage (stage 4).
+ * <p/>
+ * as in joint Feldman, each party in QUAL has his own share of the generated random key.
+ * this key can be recover by any subset of QUAL of size at least t + 1.
+ */
+public class User<T> extends meerkat.crypto.dkg.feldman.User<T> {
+
+    /**
+     * All parties participating in key generation.
+     * parties[id-1] has my info.
+     */
+    protected Party<T>[] parties;
+
+    /**
+     * gjkr secure protocol object
+     */
+    protected final Protocol<T> sdkg;
+
+    boolean isStage4;
+
+    /**
+     * constructor
+     *
+     * @param sdkg    gjkr protocol object
+     * @param channel channel object
+     */
+    public User(Protocol<T> sdkg, Channel channel) {
+        super(sdkg, channel);
+        this.sdkg = sdkg;
+        this.parties = sdkg.getParties();
+    }
+
+    /**
+     * stage1 according to the protocol
+     * 1. Pi broadcasts Cik=Aik*Bik for k = 0,...,t.
+     * 2. Pi computes the shares Sij,Sij' for j = 1,...,n and sends Sij,Sij' secretly to Pj.
+     */
+    @Override
+    protected void stage1() {
+        sdkg.computeAndBroadcastVerificationValues();
+        sdkg.sendSecrets();
+    }
+
+
+
+    @Override
+    protected void waitUntilStageOneCompleted() {
+        super.waitUntilStageOneCompleted();
+        // save the received commitments as verification values
+        ArrayList<T> temp;
+        for (int i = 0; i < n; i++) {
+            temp = parties[i].verifiableValues;
+            parties[i].verifiableValues = parties[i].commitments;
+            parties[i].commitments = temp;
+        }
+    }
+
+    /**
+     * stage2 according to the protocol
+     * Pj verifies all the shares,sharesT he received
+     * if check fails for an index i, Pj broadcasts a complaint against Pi.
+     * Pj broadcasts done message at the end of this stage
+     */
+    @Override
+    protected void stage2() {
+        sdkg.broadcastComplaints();
+        //broadcast done message after all complaints
+        channel.broadcastMessage(createMessage(DKG.Payload.Type.DONE));
+    }
+
+    /**
+     * Check if all non-aborting qualified parties have sent commitments.
+     * @return
+     */
+    protected boolean haveAllQualPartiesCommitted() {
+        for (int i : QUAL) {
+            if (parties[i - 1].aborted)
+                continue;
+            for (int k = 0; k <= t; k++) {
+                if (parties[i - 1].commitments.get(k) == null)
+                    return false;
+            }
+        }
+        return true;
+    }
+
+
+    /**
+     * Check if all non-aborting qualified parties sent a done message
+     * @return
+     */
+    protected boolean areAllQualPartiesDone() {
+        for (int i : QUAL) {
+            if (parties[i - 1].aborted)
+                continue;
+            for (int k = 0; k <= t; k++) {
+                if (!parties[i - 1].ysDoneFlag)
+                    return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Check if at least t + 1 secrets were received foreach i in QUAL that aborted
+     * @return
+     */
+    protected boolean haveReceivedEnoughSecretShares() {
+        for (int i : QUAL) {
+            if (parties[i - 1].aborted && parties[i - 1].recoverSharesSet.size() <= t)
+                return false;
+        }
+        return true;
+    }
+
+    /**
+     * broadcast commitments and recover parties information if necessary
+     */
+    private void resolveQualifyingPublicKey() {
+        sdkg.broadcastCommitments();
+        // wait until all parties in QUAL broadcast their commitments or aborted
+        while (!stop && !haveAllQualPartiesCommitted())
+            waitAndHandleReceivedMessages();
+
+        if (stop)
+            return;
+
+        sdkg.computeAndBroadcastComplaints(QUAL);
+
+        //broadcast done message after all complaints
+        channel.broadcastMessage(createMessage(DKG.Payload.Type.DONE));
+
+        // wait until all parties in QUAL done or aborted
+        while (!stop && !areAllQualPartiesDone())
+            waitAndHandleReceivedMessages();
+
+        if (stop)
+            return;
+
+        // broadcast i private secret foreach i in QUAL that aborted
+        for (int i : QUAL) {
+            if (parties[i - 1].aborted) {
+                sdkg.broadcastAnswer(parties[i - 1].share, parties[i - 1].shareT, i);
+            }
+        }
+        // wait until at least t + 1 secrets will received foreach i in QUAL that aborted
+        while (!stop && !haveReceivedEnoughSecretShares())
+            waitAndHandleReceivedMessages();
+
+        if (stop)
+            return;
+
+        Arithmetic<BigInteger> arithmetic = new Fp(sdkg.getQ());
+        // restore necessary information
+        for (int i = 0; i < n; i++) {
+            if (parties[i].recoverSharesSet.isEmpty()) {
+                continue;
+            }
+            Polynomial.Point[] shares = new Polynomial.Point[t + 1];
+            int j = 0;
+            for (Polynomial.Point share : parties[i].recoverSharesSet) {
+                shares[j++] = share;
+                if (j >= shares.length) {
+                    break;
+                }
+            }
+            Polynomial polynomial = SecretSharing.recoverPolynomial(shares, arithmetic);
+            BigInteger[] coefficients = polynomial.getCoefficients();
+            for (int k = 0; k <= t; k++) {
+                parties[i].commitments.add(k, group.multiply(g, coefficients[k]));
+            }
+            parties[i].share = new Polynomial.Point(BigInteger.valueOf(id), polynomial);
+        }
+    }
+
+    /**
+     * notifies message handler and message handler that stage 4 was started
+     */
+    protected void setStage4() {
+        isStage4 = true;
+    }
+
+    @Override
+    protected void stage4() {
+        setStage4();
+        resolveQualifyingPublicKey();
+        if (stop) return;
+        super.stage4();
+    }
+
+
+    /**
+     * if !isStage4  as super, with extension to double secret message
+     * else answer message is valid if:
+     * 1. it was received in broadcast chanel
+     * 2. secret.j == sender
+     * 3. QUAL contains i and j
+     */
+    protected boolean isValidAnswerMessage(int sender, boolean isBroadcast, DKG.ShareMessage doubleSecretMessage) {
+        if (!isStage4) {
+            return super.isValidAnswerMessage(sender, isBroadcast, doubleSecretMessage);
+        } else {
+            int i = doubleSecretMessage.getI();
+            int j = doubleSecretMessage.getJ();
+            return isBroadcast && j == sender && parties[i - 1].aborted && !parties[j - 1].aborted
+                    && QUAL.contains(i) && QUAL.contains(j);
+        }
+    }
+
+
+    /**
+     * as in super with respect to protocol stage
+     */
+    @Override
+    protected boolean isValidDoneMessage(int sender, boolean isBroadcast) {
+        if (!isStage4) {
+            return super.isValidDoneMessage(sender, isBroadcast);
+        } else {
+            return isBroadcast && !parties[sender - 1].ysDoneFlag;
+        }
+    }
+
+    /**
+     * use only in stage4
+     * complaint message is valid if:
+     * 1. it was received in broadcast chanel
+     * 2. secret.j == sender
+     * 3. QUAL contains i and j
+     */
+    protected boolean isValidComplaintMessage(int sender, boolean isBroadcast,
+                                              DKG.ShareMessage complaintMessage) {
+        int i = complaintMessage.getI();
+        int j = complaintMessage.getJ();
+        return isBroadcast && j == sender && QUAL.contains(i) && QUAL.contains(j);
+    }
+
+
+    @Override
+    public void handleMessage(Comm.BroadcastMessage envelope) throws InvalidProtocolBufferException {
+        int sender = envelope.getSender();
+        boolean isBroadcast = !envelope.getIsPrivate();
+        DKG.Payload msg = DKG.Payload.parseFrom(envelope.getPayload());
+        switch (msg.getType()) {
+            case SHARE:
+                /**
+                 * as in super, with extension to double secret message
+                 */
+                DKG.ShareMessage doubleSecretMessage = msg.getShare();
+                if (isValidSecretMessage(sender, isBroadcast, doubleSecretMessage)) {
+                    int i = doubleSecretMessage.getI();
+                    synchronized (parties[i - 1]) {
+                        parties[i - 1].share = extractShare(id, doubleSecretMessage.getShare());
+                        parties[i - 1].shareT = extractShare(id, doubleSecretMessage.getShareT());
+                        parties[i - 1].notify();
+                    }
+                }
+                break;
+            case ANSWER:
+                /**
+                 * if !isStage4 as super, with extension to double secret message
+                 * else saves secret
+                 */
+                assert msg.getPayloadDataCase() == DKG.Payload.PayloadDataCase.SHARE;
+                doubleSecretMessage = msg.getShare();
+                if (isValidAnswerMessage(sender, isBroadcast, doubleSecretMessage)) {
+                    int i = doubleSecretMessage.getI();
+                    int j = doubleSecretMessage.getJ();
+                    Polynomial.Point secret = extractShare(j, doubleSecretMessage.getShare());
+                    Polynomial.Point secretT = extractShare(j, doubleSecretMessage.getShareT());
+                    synchronized (parties[i - 1]) {
+                        if (!isStage4) {
+                            if (sdkg.isValidShare(secret, secretT, parties[j - 1].verifiableValues, i)) {
+                                parties[i - 1].complaints[j - 1] = meerkat.crypto.dkg.feldman.Protocol.ComplaintState.NonDisqualified;
+
+                            } else {
+                                parties[i - 1].complaints[j - 1] = meerkat.crypto.dkg.feldman.Protocol.ComplaintState.Disqualified;
+                            }
+                            if (j == id) {
+                                parties[i - 1].share = secret;
+                                parties[i - 1].shareT = secretT;
+                            }
+                        } else if (sdkg.isValidShare(secret, secretT, parties[i - 1].verifiableValues, j)) {
+                            parties[i - 1].recoverSharesSet.add(secret);
+                        }
+                        parties[i - 1].notify();
+                    }
+                }
+                break;
+            case DONE:
+                /**
+                 * as in super with respect to protocol state
+                 */
+                if (!isStage4)
+                    super.handleMessage(envelope);
+                else {
+                    if (isValidDoneMessage(sender, isBroadcast)) {
+                        synchronized (parties[sender - 1]) {
+                            parties[sender - 1].ysDoneFlag = true;
+                            parties[sender - 1].notify();
+                        }
+                    }
+                }
+                break;
+            case COMPLAINT:
+                /**
+                 * if !isStage4 as in super
+                 * else if secret,secretT are valid with respect to verifiableValues but
+                 *      secret is not valid with respect to commitments then
+                 *      marks i as aborted
+                 */
+                if (!isStage4) {
+                    super.handleMessage(envelope);
+                } else {
+                    assert (msg.getPayloadDataCase() == DKG.Payload.PayloadDataCase.SHARE);
+                    DKG.ShareMessage ysComplaintMessage = msg.getShare();
+                    if (isValidComplaintMessage(sender, isBroadcast, ysComplaintMessage)) {
+                        int i = ysComplaintMessage.getI();
+                        int j = ysComplaintMessage.getJ();
+                        Polynomial.Point secret = extractShare(i, ysComplaintMessage.getShare());
+                        Polynomial.Point secretT = extractShare(i, ysComplaintMessage.getShareT());
+                        if (sdkg.isValidShare(secret, secretT, parties[i - 1].verifiableValues, j)
+                                && !dkg.isValidShare(secret, parties[i - 1].commitments, j)) {
+                            synchronized (parties[i - 1]) {
+                                parties[i - 1].aborted = true;
+                                parties[i - 1].notify();
+                            }
+                        }
+                    }
+                }
+                break;
+            default:
+                super.handleMessage(envelope);
+                break;
+        }
+    }
+
+}

distributed-key-generation/src/main/java/meerkat/crypto/secretsharing/feldman/VerifiableSecretSharing.java

@@ -0,0 +1,117 @@
+package meerkat.crypto.secretsharing.feldman;
+
+import meerkat.crypto.secretsharing.shamir.Polynomial;
+import meerkat.crypto.secretsharing.shamir.SecretSharing;
+import org.factcenter.qilin.primitives.Group;
+
+import java.util.ArrayList;
+import java.math.BigInteger;
+import java.util.Random;
+
+/**
+ * Created by Tzlil on 1/27/2016.
+ *
+ * an implementation of Feldman's verifiable secret sharing scheme.
+ *
+ * allows trusted dealer to share a key x among n parties.
+ *
+ */
+public class VerifiableSecretSharing<T> extends SecretSharing {
+    /**
+     * cyclic group contains g.
+     */
+    protected final Group<T> group;
+    /**
+     * a generator of cyclic group of order q.
+     *          the generated group is a subgroup of the given group.
+     *          it must be chosen such that computing discrete logarithms is hard in this group.
+     */
+    protected final T g;
+    /**
+     * commitments to polynomial coefficients.
+     *  commitments[k] = g ^ coefficients[k] (group operation)
+     */
+    protected final ArrayList<T> commitmentsArrayList;
+
+    /**
+     * constructor
+     * @param q      a large prime.
+     * @param t      threshold. Any t+1 share holders can recover the secret,
+     *               but any set of at most t share holders cannot
+     * @param n      number of share holders
+     * @param zi      secret, chosen from Zq
+     * @param random use for generate random polynomial
+     * @param group
+     * @param q a large prime dividing group order.
+     * @param g a generator of cyclic group of order q.
+     *          the generated group is a subgroup of the given group.
+     *          it must be chosen such that computing discrete logarithms is hard in this group.
+     */
+    public VerifiableSecretSharing(int t, int n, BigInteger zi, Random random, BigInteger q, T g
+            , Group<T> group) {
+        super(t, n, zi, random,q);
+        this.g = g;
+        this.group = group;
+        assert (this.group.contains(g));
+        this.commitmentsArrayList = generateCommitments();
+    }
+
+    /**
+     * commitments[i] = g ^ polynomial.coefficients[i]
+     * @return commitments
+     */
+    private ArrayList<T> generateCommitments() {
+
+        Polynomial polynomial = getPolynomial();
+        BigInteger[] coefficients = polynomial.getCoefficients();
+        ArrayList<T> commitments = new ArrayList<T>(t + 1);
+        for (int i = 0 ; i <= t;i++){
+            commitments.add(i,group.multiply(g,coefficients[i]));
+        }
+        return commitments;
+    }
+
+    /**
+     * Compute verification value (g^{share value}) using coefficient commitments sent by dealer and my share id.
+     * @param j my share holder id
+     * @param commitments commitments to polynomial coefficients of share (received from dealer)
+     * @param group
+     *
+     * @return product of Aik ^ (j ^ k) == g ^ polynomial(i)
+     */
+    public static <T> T computeVerificationValue(int j, ArrayList<T> commitments, Group<T> group) {
+        T v = group.zero();
+        BigInteger power = BigInteger.ONE;
+        BigInteger J = BigInteger.valueOf(j);
+        for (int k = 0 ; k < commitments.size() ; k ++){
+            v = group.add(v,group.multiply(commitments.get(k),power));
+            power = power.multiply(J);
+        }
+        return v;
+    }
+
+    /**
+     * getter
+     * @return generator of group
+     */
+    public T getGenerator() {
+        return g;
+    }
+
+    /**
+     * getter
+     * @return group
+     */
+    public Group<T> getGroup(){
+        return group;
+    }
+
+    /**
+     * getter
+     * @return commitmentsArrayList
+     */
+    public ArrayList<T> getCommitmentsArrayList() {
+        return commitmentsArrayList;
+    }
+
+}

distributed-key-generation/src/main/java/meerkat/crypto/secretsharing/shamir/LagrangePolynomial.java

@@ -0,0 +1,66 @@
+package meerkat.crypto.secretsharing.shamir;
+
+import meerkat.crypto.utils.Arithmetic;
+
+import java.math.BigInteger;
+
+/**
+ * Created by Tzlil on 1/28/2016.
+ *
+ * container of lagrange polynomial
+ *
+ * Constructor is private (use {@link #lagrangePolynomials(Polynomial.Point[], Arithmetic)} to construct)
+ *
+ * l = (evaluate/divisor)* polynomial
+ *
+ * Note : image and divisor stored separately for avoiding lose of information by division
+ */
+class LagrangePolynomial{
+    public final Polynomial polynomial;
+    public final BigInteger image;
+    public final BigInteger divisor;
+
+    /**
+     * inner constructor, stores all given parameters
+     * @param polynomial
+     * @param image
+     * @param divisor
+     */
+    private LagrangePolynomial(Polynomial polynomial, BigInteger image, BigInteger divisor) {
+        this.polynomial = polynomial;
+        this.image = image;
+        this.divisor = divisor;
+    }
+
+    /**
+     * static method
+     * @param points array points s.t there are no couple of points that shares the same x value
+     *
+     * @return the lagrange polynomials that mach to given points.
+     *         in case there exists i != j s.t points[i].x == points[j].x returns null.
+     */
+    public static LagrangePolynomial[] lagrangePolynomials(Polynomial.Point[] points,Arithmetic<BigInteger> arithmetic) {
+        Polynomial one = new Polynomial(new BigInteger[]{BigInteger.ONE},arithmetic);
+        LagrangePolynomial[] lagrangePolynomials = new LagrangePolynomial[points.length];
+        Polynomial[] factors = new Polynomial[points.length];
+        for (int i = 0 ; i < factors.length ; i++){
+            factors[i] = new Polynomial(new BigInteger[]{points[i].x.negate(),BigInteger.ONE},arithmetic); // X - Xi
+        }
+        Polynomial product;
+        BigInteger divisor;
+        for(int i = 0; i < points.length; i ++) {
+            product = one;
+            divisor = BigInteger.ONE;
+            for (int j = 0; j < points.length; j++) {
+                if (i != j) {
+                    divisor = arithmetic.mul(divisor,arithmetic.sub(points[i].x,points[j].x));
+                    product = product.mul(factors[j]);
+                }
+            }
+            if(divisor.equals(BigInteger.ZERO))
+                return null;
+            lagrangePolynomials[i] = new LagrangePolynomial(product,points[i].y,divisor);
+        }
+        return lagrangePolynomials;
+    }
+}

distributed-key-generation/src/main/java/meerkat/crypto/secretsharing/shamir/Polynomial.java

@@ -0,0 +1,208 @@
+package meerkat.crypto.secretsharing.shamir;
+
+import meerkat.crypto.utils.Arithmetic;
+
+import java.math.BigInteger;
+import java.util.Arrays;
+
+/**
+ * Created by Tzlil on 1/27/2016.
+ */
+public class Polynomial implements Comparable<Polynomial> {
+    private final int degree;
+    private final BigInteger[] coefficients;
+    private final Arithmetic<BigInteger> arithmetic;
+
+    /**
+     * constructor
+     * @param coefficients
+     * @param arithmetic
+     *        degree set as max index such that coefficients[degree] not equals zero
+     */
+    public Polynomial(BigInteger[] coefficients,Arithmetic<BigInteger> arithmetic) {
+        int d = coefficients.length - 1;
+        while (d >  0 && coefficients[d].equals(BigInteger.ZERO)){
+            d--;
+        }
+        this.degree = d;
+        this.coefficients = coefficients;
+        this.arithmetic = arithmetic;
+    }
+
+    /**
+     * Compare to another polynomial (order by degree, then coefficients).
+     */
+    @Override
+    public int compareTo(Polynomial other) {
+        if (this.degree != other.degree)
+            return this.degree - other.degree;
+        int compare;
+        for (int i = degree; i >= degree ; i--){
+            compare = this.coefficients[i].compareTo(other.coefficients[i]);
+            if (compare != 0){
+                return compare;
+            }
+        }
+        return 0;
+    }
+
+    /**
+     * @param x
+     * @return sum of coefficients[i] * (x ^ i)
+     */
+    public BigInteger evaluate(BigInteger x){
+        BigInteger result = BigInteger.ZERO;
+        BigInteger power = BigInteger.ONE;
+        for(int i = 0 ; i <= degree ; i++){
+            result = arithmetic.add(result,arithmetic.mul(coefficients[i],power));
+            power = power.multiply(x);
+        }
+        return result;
+    }
+
+    /**
+     * @param points
+     * @return polynomial of minimal degree which goes through all points.
+     *  If there exists i != j s.t points[i].x == points[j].x, method returns null.
+     */
+    public static Polynomial interpolation(Point[] points, Arithmetic<BigInteger> arithmetic) {
+        LagrangePolynomial[] l = LagrangePolynomial.lagrangePolynomials(points,arithmetic);
+        if (l == null){
+            return null;
+        }
+        // product = product of l[i].divisor
+        BigInteger product = BigInteger.ONE;
+        for (int i = 0; i < l.length;i++){
+            product = arithmetic.mul(product,l[i].divisor);
+        }
+
+        // factor[i] = product divided by l[i].divisor = product of l[j].divisor s.t j!=i
+        BigInteger[] factors = new BigInteger[l.length];
+        for (int i = 0; i < l.length;i++){
+            factors[i] = arithmetic.div(product,l[i].divisor);
+        }
+        int degree = l[0].polynomial.degree;
+
+        // coefficients[j] = (sum of l[i].evaluate * factor[i] * l[i].coefficients[j] s.t i!=j) divide by product =
+        //                 =  sum of l[i].evaluate * l[i].coefficients[j] / l[i].divisor s.t i!=j
+        BigInteger[] coefficients = new BigInteger[degree + 1];
+        for (int j = 0; j < coefficients.length;j++){
+            coefficients[j] = BigInteger.ZERO;
+            for (int i = 0; i < l.length; i++){
+                BigInteger current = arithmetic.mul(l[i].image,factors[i]);
+                current = arithmetic.mul(current,l[i].polynomial.coefficients[j]);
+                coefficients[j] = arithmetic.add(coefficients[j],current);
+            }
+            coefficients[j] = arithmetic.div(coefficients[j],product);
+        }
+        return new Polynomial(coefficients,arithmetic);
+    }
+
+    /**
+     * @param other
+     * @return new Polynomial of degree max(this degree,other degree) s.t for all x
+     *         new.evaluate(x) = this.evaluate(x) + other.evaluate(x)
+     */
+    public Polynomial add(Polynomial other){
+        Polynomial bigger,smaller;
+        if(this.degree < other.degree){
+            bigger = other;
+            smaller = this;
+        }else{
+            bigger = this;
+            smaller = other;
+        }
+        BigInteger[] coefficients = bigger.getCoefficients();
+
+        for (int i = 0; i <= smaller.degree ; i++){
+            coefficients[i] = arithmetic.add(smaller.coefficients[i],bigger.coefficients[i]);
+        }
+        return  new Polynomial(coefficients,other.arithmetic);
+    }
+
+    /**
+     * @param constant
+     * @return new Polynomial of degree this.degree s.t for all x
+     *         new.evaluate(x) = constant * this.evaluate(x)
+     */
+    public Polynomial mul(BigInteger constant){
+
+        BigInteger[] coefficients = this.getCoefficients();
+
+        for (int i = 0; i <= this.degree ; i++){
+            coefficients[i] = arithmetic.mul(constant,coefficients[i]);
+        }
+        return  new Polynomial(coefficients,arithmetic);
+    }
+
+    /**
+     * @param other
+     * @return new Polynomial of degree this degree + other degree + 1 s.t for all x
+     *         new.evaluate(x) = this.evaluate(x) * other.evaluate(x)
+     */
+    public Polynomial mul(Polynomial other){
+
+        BigInteger[] coefficients = new BigInteger[this.degree + other.degree + 1];
+        Arrays.fill(coefficients,BigInteger.ZERO);
+
+        for (int i = 0; i <= this.degree ; i++){
+            for (int j = 0; j <= other.degree; j++){
+                coefficients[i+j] = arithmetic.add(coefficients[i+j],arithmetic.mul(this.coefficients[i],other.coefficients[j]));
+            }
+        }
+        return  new Polynomial(coefficients,arithmetic);
+    }
+
+
+    /** getter
+     * @return copy of coefficients
+     */
+    public BigInteger[] getCoefficients() {
+        return Arrays.copyOf(coefficients,coefficients.length);
+    }
+
+    /** getter
+     * @return degree
+     */
+    public int getDegree() {
+        return degree;
+    }
+
+    /**
+     * inner class
+     * container for (x,y) x from range and y from evaluate of polynomial
+     */
+    public static class Point implements java.io.Serializable {
+        public final BigInteger x;
+        public final BigInteger y;
+
+        /**
+         * constructor
+         * @param x
+         * @param polynomial y = polynomial.evaluate(x)
+         */
+        public Point(BigInteger x, Polynomial polynomial) {
+            this.x = x;
+            this.y = polynomial.evaluate(x);
+        }
+
+        /**
+         * constructor
+         * @param x
+         * @param y
+         */
+        public Point(BigInteger x,BigInteger y) {
+            this.x = x;
+            this.y = y;
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if(!super.equals(obj))
+                return false;
+            Point other = (Point)obj;
+            return this.x.equals(other.x) && this.y.equals(other.y);
+        }
+    }
+
+}

distributed-key-generation/src/main/java/meerkat/crypto/secretsharing/shamir/SecretSharing.java

@@ -0,0 +1,123 @@
+package meerkat.crypto.secretsharing.shamir;
+
+import meerkat.crypto.utils.Arithmetic;
+import meerkat.crypto.utils.concrete.Fp;
+
+import java.math.BigInteger;
+import java.util.Random;
+
+/**
+ * Created by Tzlil on 1/27/2016.
+ * an implementation of Shamire's secret sharing scheme
+ */
+public class SecretSharing{
+    /**
+     * threshold
+     */
+    protected final int t;
+    /**
+     * number of shares
+     */
+    protected final int n;
+    /**
+     * a large prime
+     */
+    protected final BigInteger q;
+    /**
+     * random polynomial of degree s.t polynomial.evaluate(0) = secret
+     */
+    protected final Polynomial polynomial;
+
+    /**
+     * constructor
+     * @param q      a large prime.
+     * @param t      threshold. Any t+1 share holders can recover the secret,
+     *               but any set of at most t share holders cannot
+     * @param n      number of share holders
+     * @param zi      secret, chosen from Zq
+     * @param random use for generate random polynomial
+     */
+    public SecretSharing(int t, int n, BigInteger zi, Random random, BigInteger q) {
+        this.q = q;
+        this.t = t;
+        this.n = n;
+        this.polynomial = generateRandomPolynomial(zi,random);
+    }
+
+    /**
+     * @param x
+     * @param random
+     * @return new Polynomial polynomial of degree t ,such that
+     *         1. polynomial(0) = x
+     *         2. polynomial coefficients randomly chosen from Zq (except of coefficients[0] = x)
+     */
+    private Polynomial generateRandomPolynomial(BigInteger x, Random random) {
+        BigInteger[] coefficients = new BigInteger[t + 1];
+        coefficients[0] = x.mod(q);
+        int bits = q.bitLength();
+        for (int i = 1 ; i <= t; i++ ){
+            coefficients[i] = new BigInteger(bits,random).mod(q);
+        }
+        return new Polynomial(coefficients,new Fp(q));
+    }
+
+    /**
+     * @param i in range of [1,...n]
+     *
+     * @return polynomial.evaluate(i)
+     */
+    public Polynomial.Point getShare(int i){
+        assert (i > 0 && i <= n);
+        return new Polynomial.Point(BigInteger.valueOf(i), polynomial);
+    }
+
+    /**
+     * @param shares - subset of the original shares
+     *
+     * @return  evaluate of interpolation(shares) at x = 0
+     */
+    public static BigInteger recoverSecret(Polynomial.Point[] shares, Arithmetic<BigInteger> arithmetic) {
+        return recoverPolynomial(shares,arithmetic).evaluate(BigInteger.ZERO);
+    }
+    /**
+     * @param shares - subset of the original shares
+     *
+     * @return  interpolation(shares)
+     */
+    public static Polynomial recoverPolynomial(Polynomial.Point[] shares, Arithmetic<BigInteger> arithmetic) {
+        return Polynomial.interpolation(shares,arithmetic);
+    }
+
+    /**
+     * getter
+     * @return threshold
+     */
+    public int getT() {
+        return t;
+    }
+
+    /**
+     * getter
+     * @return number of share holders
+     */
+    public int getN() {
+        return n;
+    }
+
+    /**
+     * getter
+     * @return the prime was given in the constructor
+     */
+    public BigInteger getQ() {
+        return q;
+    }
+
+
+    /**
+     * getter
+     * @return the polynomial was generated in constructor
+     */
+    public Polynomial getPolynomial() {
+        return polynomial;
+    }
+}

distributed-key-generation/src/main/java/meerkat/crypto/utils/Arithmetic.java

@@ -0,0 +1,38 @@
+package meerkat.crypto.utils;
+
+/**
+ * Created by Tzlil on 3/17/2016.
+ * defines the properties of the traditional operations : add,sub,mul,div
+ * between two objects of type T
+ */
+public interface Arithmetic<T> {
+    /**
+     * addition
+     * @param a
+     * @param b
+     * @return a + b
+     */
+    T add(T a, T b);
+    /**
+     * subtraction
+     * @param a
+     * @param b
+     * @return a - b
+     */
+    T sub(T a, T b);
+    /**
+     * multiplication
+     * @param a
+     * @param b
+     * @return a * b
+     */
+    T mul(T a, T b);
+    /**
+     * division
+     * @param a
+     * @param b
+     * @return a / b
+     */
+    T div(T a, T b);
+
+}

distributed-key-generation/src/main/java/meerkat/crypto/utils/concrete/Fp.java

@@ -0,0 +1,44 @@
+package meerkat.crypto.utils.concrete;
+
+import meerkat.crypto.utils.Arithmetic;
+import org.factcenter.qilin.primitives.concrete.Zpstar;
+
+import java.math.BigInteger;
+
+/**
+ * Created by Tzlil on 3/17/2016.
+ * an implementation of Arithmetic<BigInteger> over prime fields: integers modulo p
+ */
+public class Fp implements Arithmetic<BigInteger> {
+    public final BigInteger p;
+    private final Zpstar zp;
+
+    /**
+     * constructor
+     * @param p prime
+     */
+    public Fp(BigInteger p) {
+        this.p = p;
+        this.zp = new Zpstar(p);
+    }
+
+    @Override
+    public BigInteger add(BigInteger a, BigInteger b){
+        return a.add(b).mod(p);
+    }
+
+    @Override
+    public BigInteger sub(BigInteger a, BigInteger b){
+        return a.add(p).subtract(b).mod(p);
+    }
+
+    @Override
+    public BigInteger mul(BigInteger a, BigInteger b){
+        return zp.add(a,b);
+    }
+
+    @Override
+    public BigInteger div(BigInteger a, BigInteger b){
+        return mul(a,zp.negate(b));
+    }
+}

distributed-key-generation/src/main/proto/meerkat/DKG.proto

@@ -0,0 +1,46 @@
+syntax = "proto3";
+
+package meerkat;
+
+option java_package = "meerkat.protobuf";
+
+message Payload {
+    enum Type {
+        SHARE = 0;
+        COMMITMENT = 1;
+        COMPLAINT = 2;
+        DONE = 3;
+        ANSWER = 4;
+        YCOMMITMENT = 5;
+        YCOMPLAINT = 6;
+        YANSWER = 7;
+        ABORT = 8;
+    }
+
+
+    // Type of message in protocol
+    Type type = 1;
+
+    oneof payload_data {
+        IDMessage id = 5;
+        ShareMessage share = 6;
+        CommitmentMessage commitment = 7;
+    }
+}
+
+message IDMessage {
+    int32 id = 1;
+}
+
+message ShareMessage {
+    int32 i = 1;
+    int32 j = 2;
+    bytes share = 3;
+    // For double shares (used in GJKR protocol)
+    bytes share_t = 4;
+}
+
+message CommitmentMessage {
+    int32 k = 1;
+    bytes commitment = 2;
+}

distributed-key-generation/src/test/java/meerkat/crypto/dkg/feldman/DKGMaliciousUser.java

@@ -0,0 +1,73 @@
+package meerkat.crypto.dkg.feldman;
+
+import meerkat.comm.Channel;
+
+import java.math.BigInteger;
+import java.util.*;
+
+/**
+ * Created by Tzlil on 3/21/2016.
+ */
+public class DKGMaliciousUser<T> extends User<T> {
+
+    private final Protocol<T> maliciousDkg;
+    private final Set<Integer> falls;
+    public DKGMaliciousUser(Protocol<T> dkg, Protocol<T> maliciousDKG, Channel channel, Set<Integer> falls) {
+        super(dkg, channel);
+        this.falls = falls;
+        this.maliciousDkg = maliciousDKG;
+        maliciousDKG.setParties(parties);
+    }
+
+    public static Set<Integer> selectFallsRandomly(Set<Integer> ids, Random random){
+        Set<Integer> falls = new HashSet<Integer>();
+        ArrayList<Integer> idsList = new ArrayList<Integer>();
+        for (int id : ids){
+            idsList.add(id);
+        }
+        int fallsSize = random.nextInt(idsList.size()) + 1;// 1 - (n-1)
+        while (falls.size() < fallsSize){
+            falls.add(idsList.remove(random.nextInt(idsList.size())));
+        }
+        return falls;
+    }
+
+    public static <T> Protocol<T> generateMaliciousDKG(Protocol<T> dkg,Channel channel,Random random){
+        BigInteger q = dkg.getQ();
+        BigInteger zi = new BigInteger(q.bitLength(), random).mod(q);
+        Protocol<T> malicious = new Protocol<T>(dkg.getT(),dkg.getN(),zi,random,dkg.getQ()
+                ,dkg.getGenerator(),dkg.getGroup(),dkg.getId(),dkg.getEncoder());
+        malicious.setChannel(channel);
+        return malicious;
+    }
+
+    @Override
+    public void stage1() {
+        dkg.broadcastCommitments();
+        sendSecrets(); //insteadof crypto.sendSecrets(channel);
+    }
+
+    @Override
+    public void stage3() {
+        maliciousDkg.answerAllComplainingPlayers();
+    }
+
+    @Override
+    public void stage4(){
+        // do nothing
+    }
+
+    private void sendSecrets(){
+        for (int j = 1; j <= n ; j++){
+            if(j != id){
+                if(falls.contains(j)){
+                    maliciousDkg.sendSecret(j);
+                }else {
+                    dkg.sendSecret(j);
+                }
+            }
+        }
+    }
+
+
+}

distributed-key-generation/src/test/java/meerkat/crypto/dkg/feldman/DKGTest.java

@@ -0,0 +1,170 @@
+package meerkat.crypto.dkg.feldman;
+
+import meerkat.comm.ChannelImpl;
+import meerkat.crypto.utils.Arithmetic;
+import meerkat.crypto.utils.concrete.Fp;
+import meerkat.comm.Channel;
+import meerkat.crypto.secretsharing.feldman.VerifiableSecretSharing;
+import meerkat.crypto.secretsharing.shamir.Polynomial;
+import meerkat.crypto.secretsharing.shamir.SecretSharing;
+import meerkat.crypto.utils.BigIntegerByteEncoder;
+import meerkat.crypto.utils.GenerateRandomPrime;
+import org.factcenter.qilin.primitives.Group;
+import org.factcenter.qilin.primitives.concrete.Zpstar;
+import org.factcenter.qilin.util.ByteEncoder;
+import org.junit.Test;
+
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Random;
+import java.util.Set;
+
+/**
+ * Created by Tzlil on 3/21/2016.
+ */
+public class DKGTest {
+
+    int tests = 10;
+    BigInteger p = GenerateRandomPrime.SafePrime100Bits;
+    BigInteger q = p.subtract(BigInteger.ONE).divide(BigInteger.valueOf(2));
+    Group<BigInteger> group = new Zpstar(p);
+    Arithmetic<BigInteger> arithmetic = new Fp(q);
+    int t = 9;
+    int n = 20;
+
+    public void oneTest(Testable testable) throws Exception {
+        for (int i = 0; i < testable.threads.length ; i++){
+            testable.threads[i].start();
+        }
+        for (int i = 0; i < testable.threads.length ; i++){
+            testable.threads[i].join();
+        }
+
+        // got the right public value
+        BigInteger publicValue = group.multiply(testable.g,testable.secret);
+        for (int i: testable.valids){
+            assert (testable.dkgs[i - 1].getPublicValue().equals(publicValue));
+        }
+
+        // assert valid verification values
+        BigInteger expected,verification;
+        for (int i: testable.valids){
+            expected = group.multiply(testable.g, testable.dkgs[i - 1].getShare().y);
+            verification = VerifiableSecretSharing.computeVerificationValue(i, testable.dkgs[i - 1].getCommitments(), group);
+            assert (expected.equals(verification));
+        }
+
+
+        // restore the secret from shares
+        ArrayList<Polynomial.Point> sharesList = new ArrayList<Polynomial.Point>();
+
+        for (int i: testable.valids){
+            sharesList.add(testable.dkgs[i - 1].getShare());
+        }
+        Polynomial.Point[] shares = new Polynomial.Point[sharesList.size()];
+        for (int i = 0; i < shares.length; i ++){
+            shares[i] = sharesList.get(i);
+        }
+
+        BigInteger calculatedSecret = SecretSharing.recoverSecret(shares,arithmetic);
+        assert (calculatedSecret.equals(testable.secret));
+    }
+
+
+    @Test
+    public void test() throws Exception {
+        Testable testable;
+        for (int i = 0; i < tests; i++){
+            testable = new Testable(new Random());
+            oneTest(testable);
+        }
+    }
+
+    class Testable{
+        Set<Integer> valids;
+        Set<Integer> QUAL;
+        Set<Integer> aborted;
+        Set<Integer> malicious;
+        User<BigInteger>[] dkgs;
+        Thread[] threads;
+        BigInteger g;
+        BigInteger secret;
+
+        public Testable(Random random) {
+            this.dkgs = new User[n];
+            this.valids = new HashSet<Integer>();
+            this.QUAL = new HashSet<Integer>();
+            this.aborted = new HashSet<Integer>();
+            this.malicious = new HashSet<Integer>();
+            this.threads = new Thread[n];
+            this.g = sampleGenerator(random);
+            ArrayList<Integer> ids = new ArrayList<Integer>();
+            for (int id = 1; id<= n ; id++){
+                ids.add(id);
+            }
+            int id;
+            BigInteger s;
+            Protocol<BigInteger> dkg;
+            this.secret = BigInteger.ZERO;
+            ChannelImpl channels = new ChannelImpl();
+            ByteEncoder<BigInteger> byteEncoder = new BigIntegerByteEncoder();
+            while (!ids.isEmpty()) {
+                id = ids.remove(random.nextInt(ids.size()));
+                Channel channel  = channels.getChannel(id);
+                s = randomIntModQ(random);
+                dkg = new meerkat.crypto.dkg.feldman.Protocol<BigInteger>(t, n, s, random, q, g, group, id,byteEncoder);
+                dkgs[id - 1] = randomDKGUser(id,channel,dkg,random);
+                threads[id - 1] = new Thread(dkgs[id - 1]);
+                if(QUAL.contains(id)){
+                    this.secret =  this.secret.add(s).mod(q);
+                }
+            }
+
+        }
+
+        public User<BigInteger> randomDKGUser(int id, Channel channel, Protocol<BigInteger> dkg, Random random){
+            if (QUAL.size() <= t) {
+                valids.add(id);
+                QUAL.add(id);
+                return new User<BigInteger>(dkg,channel);
+            }else{
+                int type = random.nextInt(3);
+                switch (type){
+                    case 0:// regular
+                        valids.add(id);
+                        QUAL.add(id);
+                        return new User<BigInteger>(dkg,channel);
+                    case 1:// abort
+                        int abortStage = random.nextInt(2) + 1; // 1 or 2
+                        aborted.add(id);
+                        if (abortStage == 2){
+                            QUAL.add(id);
+                        }
+                        return new DKGUserImplAbort(dkg,channel,abortStage);
+                    case 2:// malicious
+                        malicious.add(id);
+                        Set<Integer> falls = DKGMaliciousUser.selectFallsRandomly(valids,random);
+                        Protocol<BigInteger> maliciousDKG = DKGMaliciousUser.generateMaliciousDKG(dkg,channel,random);
+                        return new DKGMaliciousUser(dkg,maliciousDKG,channel,falls);
+                    default:
+                        return null;
+                }
+            }
+        }
+
+        public BigInteger sampleGenerator(Random random){
+            BigInteger ZERO = group.zero();
+            BigInteger g;
+            do {
+                g = group.sample(random);
+            } while (!g.equals(ZERO) && !group.multiply(g, q).equals(ZERO));
+            return g;
+        }
+
+        public BigInteger randomIntModQ(Random random){
+            return new BigInteger(q.bitLength(), random).mod(q);
+        }
+
+    }
+}

distributed-key-generation/src/test/java/meerkat/crypto/dkg/feldman/DKGUserImplAbort.java

@@ -0,0 +1,65 @@
+package meerkat.crypto.dkg.feldman;
+
+import meerkat.comm.Channel;
+import meerkat.protobuf.DKG;
+
+import static meerkat.crypto.dkg.comm.MessageUtils.createMessage;
+
+/**
+ * Created by Tzlil on 3/14/2016.
+ */
+public class DKGUserImplAbort<T> extends User<T> {
+
+    final int abortStage;
+    int stage;
+    public DKGUserImplAbort(Protocol<T> dkg, Channel channel, int abortStage) {
+        super(dkg, channel);
+        this.abortStage = abortStage;// 1 - 2
+        this.stage = 1;
+    }
+
+
+    private void sendAbort(){
+        channel.broadcastMessage(createMessage(DKG.Payload.Type.ABORT));
+    }
+
+    @Override
+    protected void stage1() {
+        if(stage < abortStage)
+            super.stage1();
+        else if(stage == abortStage){
+            sendAbort();
+        }
+        stage++;
+    }
+
+    @Override
+    protected void stage2() {
+        if(stage < abortStage)
+            super.stage2();
+        else if(stage == abortStage){
+            sendAbort();
+        }
+        stage++;
+    }
+
+    @Override
+    protected void stage3() {
+        if(stage < abortStage)
+            super.stage3();
+        else if(stage == abortStage){
+            sendAbort();
+        }
+        stage++;
+    }
+
+    @Override
+    protected void stage4() {
+        if(stage < abortStage)
+            super.stage4();
+        else if(stage == abortStage){
+            sendAbort();
+        }
+        stage++;
+    }
+}

distributed-key-generation/src/test/java/meerkat/crypto/dkg/gjkr/SDKGMaliciousUserImpl.java

@@ -0,0 +1,61 @@
+package meerkat.crypto.dkg.gjkr;
+
+import meerkat.comm.Channel;
+
+import java.math.BigInteger;
+import java.util.Random;
+import java.util.Set;
+
+/**
+ * Created by Tzlil on 3/29/2016.
+ */
+public class SDKGMaliciousUserImpl<T> extends User<T> {
+
+    private final Protocol<T> maliciousSDKG;
+    private final Set<Integer> falls;
+    public SDKGMaliciousUserImpl(Protocol<T> sdkg, Protocol<T> maliciousSDKG
+            , Channel channel, Set<Integer> falls) {
+        super(sdkg, channel);
+        this.falls = falls;
+        this.maliciousSDKG = maliciousSDKG;
+        maliciousSDKG.setParties(parties);
+    }
+
+    public static<T> Protocol<T> generateMaliciousSDKG(Protocol<T> sdkg,Channel channel,Random random){
+        BigInteger q = sdkg.getQ();
+        BigInteger zi = new BigInteger(q.bitLength(), random).mod(q);
+        Protocol<T> malicious = new Protocol<T>(sdkg.getT(),sdkg.getN(),zi,random,sdkg.getQ()
+                ,sdkg.getGenerator(),sdkg.getH(),sdkg.getGroup(),sdkg.getId(),sdkg.getEncoder());
+        malicious.setChannel(channel);
+        return malicious;
+    }
+
+    @Override
+    public void stage1() {
+        sdkg.computeAndBroadcastVerificationValues();
+        sendSecrets(); //insteadof crypto.sendSecrets(channel);
+    }
+
+    @Override
+    public void stage3() {
+        maliciousSDKG.answerAllComplainingPlayers();
+    }
+
+    @Override
+    public void stage4(){
+        //do nothing
+    }
+
+    private void sendSecrets(){
+        for (int j = 1; j <= n ; j++){
+            if(j != id){
+                if(falls.contains(j)){
+                    maliciousSDKG.sendSecret(j);
+                }else {
+                    sdkg.sendSecret(j);
+                }
+            }
+        }
+    }
+
+}

distributed-key-generation/src/test/java/meerkat/crypto/dkg/gjkr/SDKGTest.java

@@ -0,0 +1,206 @@
+package meerkat.crypto.dkg.gjkr;
+
+import meerkat.comm.ChannelImpl;
+import meerkat.crypto.utils.Arithmetic;
+import meerkat.crypto.utils.concrete.Fp;
+import meerkat.comm.Channel;
+import meerkat.crypto.secretsharing.feldman.VerifiableSecretSharing;
+import meerkat.crypto.dkg.feldman.DKGMaliciousUser;
+import meerkat.crypto.secretsharing.shamir.Polynomial;
+import meerkat.crypto.secretsharing.shamir.SecretSharing;
+import meerkat.crypto.utils.BigIntegerByteEncoder;
+import meerkat.crypto.utils.GenerateRandomPrime;
+import org.factcenter.qilin.primitives.Group;
+import org.factcenter.qilin.primitives.concrete.Zpstar;
+import org.factcenter.qilin.util.ByteEncoder;
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.internal.runners.statements.Fail;
+
+import static org.junit.Assert.*;
+
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Random;
+import java.util.Set;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+
+/**
+ * Created by Tzlil on 3/29/2016.
+ * TODO: Separate into multiple tests,
+ * TODO: Make tests deterministic (using constant seed for random generator)
+ */
+public class SDKGTest {
+
+    private ExecutorService executorService = Executors.newCachedThreadPool();
+
+    final static int NUM_TESTS = 10;
+    BigInteger p = GenerateRandomPrime.SafePrime100Bits;
+    BigInteger q = p.subtract(BigInteger.ONE).divide(BigInteger.valueOf(2));
+    Group<BigInteger> group = new Zpstar(p);
+    Arithmetic<BigInteger> arithmetic = new Fp(q);
+    int t = 1;
+    int n = 20;
+    Random rand = new Random(1);
+
+    public void oneTest(Testable testable) throws Exception {
+        for (int i = 0; i < testable.sdkgs.length ; i++){
+            testable.futures[i] = executorService.submit(testable.sdkgs[i]);
+        }
+        for (int i = 0; i < testable.futures.length ; i++){
+            testable.futures[i].get();
+        }
+
+        // got the right public value
+        BigInteger publicValue = group.multiply(testable.g,testable.secret);
+        for (int i: testable.valids){
+            assert (testable.sdkgs[i - 1].getPublicValue().equals(publicValue));
+        }
+
+        // assert valid verification values
+        BigInteger expected,verification;
+        for (int i: testable.valids){
+            expected = group.multiply(testable.g, testable.sdkgs[i - 1].getShare().y);
+            verification = VerifiableSecretSharing.computeVerificationValue(i, testable.sdkgs[i - 1].getCommitments(), group);
+            assert (expected.equals(verification));
+        }
+
+
+        // restore the secret from shares
+        ArrayList<Polynomial.Point> sharesList = new ArrayList<Polynomial.Point>();
+
+        for (int i: testable.valids){
+            sharesList.add(testable.sdkgs[i - 1].getShare());
+        }
+        Polynomial.Point[] shares = new Polynomial.Point[sharesList.size()];
+        for (int i = 0; i < shares.length; i ++){
+            shares[i] = sharesList.get(i);
+        }
+
+        BigInteger calculatedSecret = SecretSharing.recoverSecret(shares,arithmetic);
+        assert (calculatedSecret.equals(testable.secret));
+    }
+
+
+    @Test
+    public void test() throws Exception {
+        Testable testable;
+        for (int i = 0; i < NUM_TESTS; i++) {
+            testable = new Testable(n, t, group, q, rand);
+            oneTest(testable);
+        }
+    }
+
+    static class Testable {
+        Set<Integer> valids;
+        Set<Integer> QUAL;
+        Set<Integer> aborted;
+        Set<Integer> malicious;
+        User<BigInteger>[] sdkgs;
+        Future<?>[] futures;
+        BigInteger g;
+        BigInteger h;
+        BigInteger secret;
+        Group<BigInteger> group;
+        int n;
+        int t;
+        BigInteger q;
+        Random random;
+        ChannelImpl channels = new ChannelImpl();
+
+        public Testable(int n, int t, Group<BigInteger> group, BigInteger q, Random random) {
+            this.n = n;
+            this.t = t;
+            this.group = group;
+            this.q = q;
+            this.random = random;
+            this.sdkgs = new User[n];
+            this.valids = new HashSet<Integer>();
+            this.QUAL = new HashSet<Integer>();
+            this.aborted = new HashSet<Integer>();
+            this.malicious = new HashSet<Integer>();
+            this.futures = new Future[n];
+            this.g = sampleGenerator(random);
+            this.h = group.multiply(g,randomIntModQ(random));
+            ArrayList<Integer> ids = new ArrayList<Integer>();
+            for (int id = 1; id<= n ; id++){
+                ids.add(id);
+            }
+            int id;
+            BigInteger s;
+            Channel channel;
+            Protocol<BigInteger> sdkg;
+            this.secret = BigInteger.ZERO;
+            ByteEncoder<BigInteger> encoder = new BigIntegerByteEncoder();
+            while (!ids.isEmpty()) {
+                id = ids.remove(random.nextInt(ids.size()));
+                s = randomIntModQ(random);
+                channel  = channels.getChannel(id);
+                sdkg = new Protocol<BigInteger>(t, n, s, random, q, g , h, group, id,encoder);
+                sdkgs[id - 1] = randomSDKGUser(id,channel,sdkg);
+                if(QUAL.contains(id)){
+                    this.secret =  this.secret.add(s).mod(q);
+                }
+            }
+
+        }
+
+        enum UserType {
+            HONEST,
+            FAILSTOP,
+            MALICIOUS,
+        }
+
+        public User<BigInteger> newSDKGUser(int id, Channel channel, Protocol<BigInteger> sdkg, UserType userType) {
+            switch(userType) {
+                case HONEST:
+                    valids.add(id);
+                    QUAL.add(id);
+                    return new User<BigInteger>(sdkg,channel);
+
+                case FAILSTOP:
+                    int abortStage = random.nextInt(3) + 1; // 1 or 2 or 3
+                    aborted.add(id);
+                    if (abortStage > 1){
+                        QUAL.add(id);
+                    }
+                    return new SDKGUserImplAbort(sdkg,channel,abortStage);
+
+                case MALICIOUS:
+                    malicious.add(id);
+                    Set<Integer> falls = DKGMaliciousUser.selectFallsRandomly(valids,random);
+                    Protocol<BigInteger> maliciousSDKG = SDKGMaliciousUserImpl.generateMaliciousSDKG(sdkg,channel,random);
+                    return new SDKGMaliciousUserImpl(sdkg,maliciousSDKG,channel,falls);
+
+            }
+            fail("Unknown user type");
+            return null;
+        }
+
+        public User<BigInteger> randomSDKGUser(int id, Channel channel, Protocol<BigInteger> sdkg){
+            if (QUAL.size() <= t) {
+                return newSDKGUser(id, channel, sdkg, UserType.HONEST);
+            } else {
+                UserType type = UserType.values()[random.nextInt(UserType.values().length)];
+                return newSDKGUser(id, channel, sdkg, type);
+            }
+        }
+
+        public BigInteger sampleGenerator(Random random){
+            BigInteger ZERO = group.zero();
+            BigInteger g;
+            do {
+                g = group.sample(random);
+            } while (!g.equals(ZERO) && !group.multiply(g, q).equals(ZERO));
+            return g;
+        }
+
+        public BigInteger randomIntModQ(Random random){
+            return new BigInteger(q.bitLength(), random).mod(q);
+        }
+
+    }
+}

distributed-key-generation/src/test/java/meerkat/crypto/dkg/gjkr/SDKGUserImplAbort.java

@@ -0,0 +1,80 @@
+package meerkat.crypto.dkg.gjkr;
+
+import com.google.protobuf.InvalidProtocolBufferException;
+import meerkat.crypto.dkg.comm.MessageUtils;
+import meerkat.comm.Channel;
+import meerkat.protobuf.Comm;
+import meerkat.protobuf.DKG;
+
+/**
+ * Created by Tzlil on 3/14/2016.
+ */
+public class SDKGUserImplAbort<T> extends User<T> {
+
+    public static class AbortException extends RuntimeException {
+
+    }
+
+    final int abortStage;
+    int stage;
+    public SDKGUserImplAbort(Protocol<T> sdkg, Channel channel, int abortStage) {
+        super(sdkg, channel);
+        this.abortStage = abortStage;// 1 - 4
+        this.stage = 1;
+    }
+
+    private void abort(){
+        //stopReceiver();
+        channel.broadcastMessage(MessageUtils.createMessage(DKG.Payload.Type.ABORT));
+        throw new AbortException();
+    }
+
+    @Override
+    protected void stage1() {
+        if(stage < abortStage)
+            super.stage1();
+        else if(stage == abortStage){
+            abort();
+        }
+        stage++;
+    }
+
+    @Override
+    protected void stage2() {
+        if(stage < abortStage)
+            super.stage2();
+        else if(stage == abortStage){
+            abort();
+        }
+        stage++;
+    }
+
+    @Override
+    protected void stage3() {
+        if(stage < abortStage)
+            super.stage3();
+        else if(stage == abortStage){
+            abort();
+        }
+        stage++;
+    }
+
+    @Override
+    protected void stage4() {
+        if(stage < abortStage)
+            super.stage4();
+        else if(stage == abortStage){
+            abort();
+        }
+        stage++;
+    }
+
+    @Override
+    public void run() {
+        try {
+            super.run();
+        } catch (AbortException e) {
+            // Expected
+        }
+    }
+}

distributed-key-generation/src/test/java/meerkat/crypto/secretsharing/feldman/VerifiableSecretSharingTest.java

@@ -0,0 +1,68 @@
+package meerkat.crypto.secretsharing.feldman;
+
+import meerkat.crypto.secretsharing.shamir.Polynomial;
+import org.factcenter.qilin.primitives.Group;
+import org.factcenter.qilin.primitives.concrete.Zpstar;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.Random;
+
+/**
+ * Created by Tzlil on 1/29/2016.
+ */
+public class VerifiableSecretSharingTest {
+
+
+    VerifiableSecretSharing[] verifiableSecretSharingArray;
+    int tests = 1 << 10;
+    Random random;
+
+    @Before
+    public void settings(){
+        BigInteger p = BigInteger.valueOf(2903);
+        BigInteger q = p.subtract(BigInteger.ONE).divide(BigInteger.valueOf(2));
+        Zpstar zpstar = new Zpstar(p);
+        random = new Random();
+        BigInteger g;
+        BigInteger ZERO = zpstar.zero();
+        do{
+            g = zpstar.sample(random);
+        }while (!g.equals(ZERO) && !zpstar.multiply(g,q).equals(ZERO));// sample from QRZp*
+        int t = 8;
+        int n = 20;
+        verifiableSecretSharingArray = new VerifiableSecretSharing[tests];
+        for (int i = 0; i < verifiableSecretSharingArray.length; i++){
+            verifiableSecretSharingArray[i] = new VerifiableSecretSharing(t,n
+                    ,new BigInteger(q.bitLength(),random).mod(q),random,q,g,zpstar);
+        }
+    }
+
+    public void oneTest(VerifiableSecretSharing<BigInteger> verifiableSecretSharing) throws Exception {
+        int n = verifiableSecretSharing.getN();
+        Group<BigInteger> zpstar = verifiableSecretSharing.getGroup();
+        BigInteger g = verifiableSecretSharing.getGenerator();
+        Polynomial.Point[] shares = new Polynomial.Point[n];
+        ArrayList<BigInteger> commitments = verifiableSecretSharing.getCommitmentsArrayList();
+        BigInteger[] verifications = new BigInteger[n];
+        for (int i = 1 ; i <= shares.length; i ++){
+            shares[i - 1] = verifiableSecretSharing.getShare(i);
+            verifications[i - 1] = VerifiableSecretSharing.computeVerificationValue(i,commitments,zpstar);
+        }
+        BigInteger expected;
+        for (int i = 0 ; i < shares.length ; i++){
+            expected = zpstar.multiply(g,shares[i].y);
+            assert (expected.equals(verifications[i]));
+        }
+
+    }
+
+    @Test
+    public void secretSharingTest() throws Exception {
+        for (int i = 0 ; i < verifiableSecretSharingArray.length; i ++){
+            oneTest(verifiableSecretSharingArray[i]);
+        }
+    }
+}

distributed-key-generation/src/test/java/meerkat/crypto/secretsharing/shamir/PolynomialTests/AddTest.java

@@ -0,0 +1,46 @@
+package meerkat.crypto.secretsharing.shamir.PolynomialTests;
+import meerkat.crypto.utils.GenerateRandomPolynomial;
+import meerkat.crypto.utils.Z;
+import meerkat.crypto.secretsharing.shamir.Polynomial;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.math.BigInteger;
+import java.util.Random;
+
+/**
+ * Created by Tzlil on 1/27/2016.
+ */
+public class AddTest {
+
+    Polynomial[] arr1;
+    Polynomial[] arr2;
+    int tests = 1 << 12;
+    int maxDegree = 15;
+    int bits = 128;
+    Random random;
+
+    @Before
+    public void settings(){
+        random = new Random();
+        arr1 = new Polynomial[tests];
+        arr2 = new Polynomial[tests];
+        for (int i = 0; i < arr1.length; i++){
+            arr1[i] = GenerateRandomPolynomial.generateRandomPolynomial(random.nextInt(maxDegree),bits,random,new Z());
+            arr2[i] = GenerateRandomPolynomial.generateRandomPolynomial(random.nextInt(maxDegree),bits,random,new Z());
+        }
+    }
+
+    public void oneTest(Polynomial p1, Polynomial p2){
+        Polynomial sum = p1.add(p2);
+        BigInteger x = new BigInteger(bits,random);
+        assert(sum.evaluate(x).equals(p1.evaluate(x).add(p2.evaluate(x))));
+    }
+
+    @Test
+    public void addTest(){
+        for (int i = 0 ; i < arr1.length; i ++){
+            oneTest(arr1[i],arr2[i]);
+        }
+    }
+}

distributed-key-generation/src/test/java/meerkat/crypto/secretsharing/shamir/PolynomialTests/InterpolationTest.java

@@ -0,0 +1,68 @@
+package meerkat.crypto.secretsharing.shamir.PolynomialTests;
+
+import meerkat.crypto.secretsharing.shamir.Polynomial;
+import meerkat.crypto.utils.Arithmetic;
+import meerkat.crypto.utils.concrete.Fp;
+import meerkat.crypto.utils.GenerateRandomPolynomial;
+import meerkat.crypto.utils.GenerateRandomPrime;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.math.BigInteger;
+import java.util.HashSet;
+import java.util.Random;
+import java.util.Set;
+
+/**
+ * Created by Tzlil on 1/27/2016.
+ */
+public class InterpolationTest {
+    Polynomial[] polynomials;
+    int tests = 1 << 10;
+    int maxDegree = 15;
+    int bits = 128;
+    Random random;
+    Polynomial.Point[][] pointsArrays;
+    Arithmetic<BigInteger> arithmetic;
+    BigInteger p = GenerateRandomPrime.SafePrime100Bits;
+
+    @Before
+    public void settings(){
+        random = new Random();
+        polynomials = new Polynomial[tests];
+        pointsArrays = new Polynomial.Point[tests][];
+        arithmetic = new Fp(p);
+        for (int i = 0; i < polynomials.length; i++){
+            polynomials[i] = GenerateRandomPolynomial.generateRandomPolynomial(random.nextInt(maxDegree),bits,random,p);
+            pointsArrays[i] = randomPoints(polynomials[i]);
+        }
+    }
+
+    public Polynomial.Point[] randomPoints(Polynomial polynomial){
+        Polynomial.Point[] points = new Polynomial.Point[polynomial.getDegree() + 1];
+        BigInteger x;
+        Set<BigInteger> set = new HashSet();
+        for (int i = 0; i < points.length; i++){
+            x = new BigInteger(bits,random).mod(p);
+            if(set.contains(x)){
+                i--;
+                continue;
+            }
+            set.add(x);
+            points[i] = new Polynomial.Point(x,polynomial);
+        }
+        return points;
+    }
+
+    public void oneTest(Polynomial p, Polynomial.Point[] points) throws Exception {
+        Polynomial interpolation = Polynomial.interpolation(points,arithmetic);
+        assert (p.compareTo(interpolation) == 0);
+    }
+
+    @Test
+    public void interpolationTest() throws Exception {
+        for (int i = 0; i < polynomials.length; i ++){
+            oneTest(polynomials[i],pointsArrays[i]);
+        }
+    }
+}

distributed-key-generation/src/test/java/meerkat/crypto/secretsharing/shamir/PolynomialTests/MulByConstTest.java

@@ -0,0 +1,48 @@
+package meerkat.crypto.secretsharing.shamir.PolynomialTests;
+
+import meerkat.crypto.utils.GenerateRandomPolynomial;
+import meerkat.crypto.utils.Z;
+import meerkat.crypto.secretsharing.shamir.Polynomial;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.math.BigInteger;
+import java.util.Random;
+
+/**
+ * Created by Tzlil on 1/27/2016.
+ */
+public class MulByConstTest {
+
+
+    Polynomial[] arr1;
+    BigInteger[] arr2;
+    int tests = 1 << 12;
+    int maxDegree = 15;
+    int bits = 128;
+    Random random;
+
+    @Before
+    public void settings(){
+        random = new Random();
+        arr1 = new Polynomial[tests];
+        arr2 = new BigInteger[tests];
+        for (int i = 0; i < arr1.length; i++){
+            arr1[i] = GenerateRandomPolynomial.generateRandomPolynomial(random.nextInt(maxDegree),bits,random,new Z());
+            arr2[i] = new BigInteger(bits,random);
+        }
+    }
+
+    public void oneTest(Polynomial p, BigInteger c){
+        Polynomial product = p.mul(c);
+        BigInteger x = new BigInteger(bits,random);
+        assert(product.evaluate(x).equals(p.evaluate(x).multiply(c)));
+    }
+
+    @Test
+    public void mulByConstTest(){
+        for (int i = 0 ; i < arr1.length; i ++){
+            oneTest(arr1[i],arr2[i]);
+        }
+    }
+}

distributed-key-generation/src/test/java/meerkat/crypto/secretsharing/shamir/PolynomialTests/MulTest.java

@@ -0,0 +1,48 @@
+package meerkat.crypto.secretsharing.shamir.PolynomialTests;
+
+import meerkat.crypto.utils.GenerateRandomPolynomial;
+import meerkat.crypto.utils.Z;
+import meerkat.crypto.secretsharing.shamir.Polynomial;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.math.BigInteger;
+import java.util.Random;
+
+/**
+ * Created by Tzlil on 1/27/2016.
+ */
+public class MulTest {
+
+
+    Polynomial[] arr1;
+    Polynomial[] arr2;
+    int tests = 1 << 12;
+    int maxDegree = 15;
+    int bits = 128;
+    Random random;
+
+    @Before
+    public void settings(){
+        random = new Random();
+        arr1 = new Polynomial[tests];
+        arr2 = new Polynomial[tests];
+        for (int i = 0; i < arr1.length; i++){
+            arr1[i] = GenerateRandomPolynomial.generateRandomPolynomial(random.nextInt(maxDegree),bits,random,new Z());
+            arr2[i] = GenerateRandomPolynomial.generateRandomPolynomial(random.nextInt(maxDegree),bits,random,new Z());
+        }
+    }
+
+    public void oneTest(Polynomial p1, Polynomial p2){
+        Polynomial product = p1.mul(p2);
+        BigInteger x = new BigInteger(bits,random);
+        assert(product.evaluate(x).equals(p1.evaluate(x).multiply(p2.evaluate(x))));
+    }
+
+    @Test
+    public void mulTest(){
+        for (int i = 0 ; i < arr1.length; i ++){
+            oneTest(arr1[i],arr2[i]);
+        }
+    }
+}

distributed-key-generation/src/test/java/meerkat/crypto/secretsharing/shamir/SecretSharingTest.java

@@ -0,0 +1,64 @@
+package meerkat.crypto.secretsharing.shamir;
+
+import meerkat.crypto.utils.concrete.Fp;
+import meerkat.crypto.utils.GenerateRandomPrime;
+import org.factcenter.qilin.primitives.CyclicGroup;
+import org.factcenter.qilin.primitives.concrete.Zn;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+/**
+ * Created by Tzlil on 1/29/2016.
+ */
+public class SecretSharingTest {
+
+    SecretSharing[] secretSharingArray;
+    BigInteger[] secrets;
+    CyclicGroup<BigInteger> group;
+    int tests = 1 << 10;
+    Random random;
+    BigInteger p = GenerateRandomPrime.SafePrime100Bits;
+    BigInteger q = p.subtract(BigInteger.ONE).divide(BigInteger.valueOf(2));
+
+    @Before
+    public void settings(){
+        group = new Zn(q);
+        int t = 9;
+        int n = 20;
+        random = new Random();
+        secretSharingArray = new SecretSharing[tests];
+        secrets = new BigInteger[tests];
+
+        for (int i = 0; i < secretSharingArray.length; i++){
+            secrets[i] = group.sample(random);
+            secretSharingArray[i] = new SecretSharing(t,n,secrets[i],random,q);
+        }
+    }
+
+    public void oneTest(SecretSharing secretSharing, BigInteger secret) throws Exception {
+        int t = secretSharing.getT();
+        int n = secretSharing.getN();
+        Polynomial.Point[] shares = new Polynomial.Point[t + 1];
+        List<Integer> indexes = new ArrayList<Integer>(n);
+        for (int i = 1 ; i <= n; i ++){
+            indexes.add(i);
+        }
+        for (int i = 0 ; i < shares.length ; i++){
+            shares[i] = secretSharing.getShare(indexes.remove(random.nextInt(indexes.size())));
+        }
+        BigInteger calculated = SecretSharing.recoverSecret(shares,new Fp(q));
+        assert (secret.equals(calculated));
+    }
+
+    @Test
+    public void secretSharingTest() throws Exception {
+        for (int i = 0 ; i < secretSharingArray.length; i ++){
+            oneTest(secretSharingArray[i],secrets[i]);
+        }
+    }
+}

distributed-key-generation/src/test/java/meerkat/crypto/utils/BigIntegerByteEncoder.java

@@ -0,0 +1,28 @@
+package meerkat.crypto.utils;
+
+import java.math.BigInteger;
+
+/**
+ * Created by Tzlil on 4/7/2016.
+ */
+public class BigIntegerByteEncoder implements org.factcenter.qilin.util.ByteEncoder<BigInteger> {
+    @Override
+    public byte[] encode(BigInteger input) {
+        return input.toByteArray();
+    }
+
+    @Override
+    public BigInteger decode(byte[] input) {
+        return new BigInteger(1,input);
+    }
+
+    @Override
+    public int getMinLength() {
+        return 0;
+    }
+
+    @Override
+    public BigInteger denseDecode(byte[] input) {
+        return decode(input);
+    }
+}

distributed-key-generation/src/test/java/meerkat/crypto/utils/GenerateRandomPolynomial.java

@@ -0,0 +1,30 @@
+package meerkat.crypto.utils;
+
+import meerkat.crypto.secretsharing.shamir.Polynomial;
+import meerkat.crypto.utils.concrete.Fp;
+
+import java.math.BigInteger;
+import java.util.Random;
+
+/**
+ * Created by Tzlil on 1/27/2016.
+ */
+public class GenerateRandomPolynomial {
+
+    public static Polynomial generateRandomPolynomial(int degree, int bits, Random random, Arithmetic<BigInteger> arithmetic) {
+        BigInteger[] coefficients = new BigInteger[degree + 1];
+
+        for (int i = 0 ; i <= degree; i++ ){
+            coefficients[i] = new BigInteger(bits,random); // sample from Zp [0,... q-1]
+        }
+        return new Polynomial(coefficients,arithmetic);
+    }
+
+    public static Polynomial generateRandomPolynomial(int degree,int bits,Random random,BigInteger p) {
+        BigInteger[] coefficients = generateRandomPolynomial(degree,bits,random,new Fp(p)).getCoefficients();
+        for (int i = 0; i<coefficients.length;i++){
+            coefficients[i] = coefficients[i].mod(p);
+        }
+        return new Polynomial(coefficients,new Fp(p));
+    }
+}

distributed-key-generation/src/test/java/meerkat/crypto/utils/GenerateRandomPrime.java

@@ -0,0 +1,30 @@
+package meerkat.crypto.utils;
+
+import java.math.BigInteger;
+import java.util.Random;
+
+/**
+ * Created by Tzlil on 3/28/2016.
+ */
+public class GenerateRandomPrime {
+    private final static int Certainty = 10000;
+    public final static BigInteger SafePrime100Bits = new BigInteger("146407324427772525685319783363");
+
+    public static BigInteger generateRandomPrime(int bits, Random random) {
+        BigInteger p;
+        do {
+            p = new BigInteger(bits, random);
+        } while (!p.isProbablePrime(Certainty));
+        return p;
+    }
+
+    public static BigInteger generateRandomSafePrime(int bits, Random random) {
+        BigInteger p;
+        BigInteger q;
+        do {
+            p = generateRandomPrime(bits, random);
+            q = p.subtract(BigInteger.ONE).divide(BigInteger.valueOf(2));
+        } while (!q.isProbablePrime(Certainty));
+        return q;
+    }
+}

distributed-key-generation/src/test/java/meerkat/crypto/utils/Z.java

@@ -0,0 +1,28 @@
+package meerkat.crypto.utils;
+
+import java.math.BigInteger;
+
+/**
+ * Created by Tzlil on 4/8/2016.
+ */
+public class Z implements Arithmetic<BigInteger> {
+    @Override
+    public BigInteger add(BigInteger a, BigInteger b) {
+        return a.add(b);
+    }
+
+    @Override
+    public BigInteger sub(BigInteger a, BigInteger b) {
+        return a.subtract(b);
+    }
+
+    @Override
+    public BigInteger mul(BigInteger a, BigInteger b) {
+        return a.multiply(b);
+    }
+
+    @Override
+    public BigInteger div(BigInteger a, BigInteger b) {
+        return a.divide(b);
+    }
+}

meerkat-common/src/main/java/meerkat/bulletinboard/AsyncBulletinBoardClient.java

@@ -13,6 +13,7 @@ public interface AsyncBulletinBoardClient extends BulletinBoardClient {
 
     /**
      * Post a message to the bulletin board in an asynchronous manner
+     * The message may be broken up by the client into a batch message, depending on implementation
      * @param msg is the message to be posted
      * @param callback is a class containing methods to handle the result of the operation
      * @return a unique message ID for the message, that can be later used to retrieve the batch
@@ -51,30 +52,30 @@ public interface AsyncBulletinBoardClient extends BulletinBoardClient {
      * It does not close the batch
      * @param signerId is the canonical form for the ID of the sender of this batch
      * @param batchId is a unique (per signer) ID for this batch
-     * @param batchDataList is the (canonically ordered) list of data comprising the portion of the batch to be posted
+     * @param batchChunkList is the (canonically ordered) list of data comprising the portion of the batch to be posted
      * @param startPosition is the location (in the batch) of the first entry in batchDataList
      *                      (optionally used to continue interrupted post operations)
      *                      The first position in the batch is position 0
      * @param callback is a callback function class for handling results of the operation
      */
-    public void postBatchData(byte[] signerId, int batchId, List<BatchData> batchDataList,
+    public void postBatchData(byte[] signerId, int batchId, List<BatchChunk> batchChunkList,
                               int startPosition, FutureCallback<Boolean> callback);
 
     /**
      * Overloading of the postBatchData method which starts at the first position in the batch
      */
-    public void postBatchData(byte[] signerId, int batchId, List<BatchData> batchDataList, FutureCallback<Boolean> callback);
+    public void postBatchData(byte[] signerId, int batchId, List<BatchChunk> batchChunkList, FutureCallback<Boolean> callback);
 
     /**
      * Overloading of the postBatchData method which uses ByteString
      */
-    public void postBatchData(ByteString signerId, int batchId, List<BatchData> batchDataList,
+    public void postBatchData(ByteString signerId, int batchId, List<BatchChunk> batchChunkList,
                               int startPosition, FutureCallback<Boolean> callback);
 
     /**
      * Overloading of the postBatchData method which uses ByteString and starts at the first position in the batch
      */
-    public void postBatchData(ByteString signerId, int batchId, List<BatchData> batchDataList, FutureCallback<Boolean> callback);
+    public void postBatchData(ByteString signerId, int batchId, List<BatchChunk> batchChunkList, FutureCallback<Boolean> callback);
 
     /**
      * Attempts to close a batch message
@@ -96,6 +97,7 @@ public interface AsyncBulletinBoardClient extends BulletinBoardClient {
      * Note that if messages haven't been "fully posted", this might return a different
      * set of messages in different calls. However, messages that are fully posted
      * are guaranteed to be included.
+     * Also: batch messages are returned as stubs.
      * @param filterList return only messages that match the filters (null means no filtering).
      * @param callback is a callback function class for handling results of the operation
      */
@@ -103,10 +105,10 @@ public interface AsyncBulletinBoardClient extends BulletinBoardClient {
 
     /**
      * Read a given batch message from the bulletin board
-     * @param batchSpecificationMessage contains the data required to specify a single batch instance
+     * @param msgID is the batch message ID to be read
      * @param callback is a callback class for handling the result of the operation
      */
-    public void readBatch(BatchSpecificationMessage batchSpecificationMessage, FutureCallback<BulletinBoardMessage> callback);
+    public void readBatch(MessageID msgID, FutureCallback<BulletinBoardMessage> callback);
 
 
     /**

meerkat-common/src/main/java/meerkat/bulletinboard/BatchDigitalSignature.java

@@ -1,34 +0,0 @@
-package meerkat.bulletinboard;
-
-import meerkat.crypto.DigitalSignature;
-import meerkat.protobuf.BulletinBoardAPI.BeginBatchMessage;
-import meerkat.protobuf.BulletinBoardAPI.BatchData;
-import meerkat.protobuf.Crypto.Signature;
-
-import java.security.InvalidKeyException;
-import java.security.SignatureException;
-import java.security.cert.CertificateException;
-import java.util.List;
-
-/**
- * Created by Arbel Deutsch Peled on 20-Dec-15.
- * Extends the DigitalSignature interface with methods for signing and authenticating Batch messages
- */
-public interface BatchDigitalSignature extends DigitalSignature {
-
-    /**
-     * Appends the batch data to the signed content (ignoring the signature)
-     * @param completeBatch contains all the data about the batch
-     * @throws SignatureException
-     */
-    public void updateContent(CompleteBatch completeBatch) throws SignatureException;
-
-    /**
-     * Performs a complete verification process on the given batch message
-     * @param completeBatch contains the batch data as well as the signature
-     * @return TRUE if the batch is verified and FALSE otherwise
-     * @throws SignatureException | SignatureException | InvalidKeyException when underlying methods do so
-     */
-    public boolean verify(CompleteBatch completeBatch) throws SignatureException, CertificateException, InvalidKeyException;
-
-}

meerkat-common/src/main/java/meerkat/bulletinboard/BulletinBoardClient.java

@@ -5,7 +5,6 @@ import meerkat.protobuf.Voting.*;
 
 import static meerkat.protobuf.BulletinBoardAPI.*;
 
-import java.util.Collection;
 import java.util.List;
 
 /**
@@ -21,20 +20,13 @@ public interface BulletinBoardClient {
 
     /**
      * Post a message to the bulletin board in a synchronous manner
+     * The message may be broken up by the client into a batch message depending on implementation
      * @param msg is the message to be posted
      * @return a unique message ID for the message, that can be later used to retrieve the batch
      * @throws CommunicationException
      */
     MessageID postMessage(BulletinBoardMessage msg) throws CommunicationException;
 
-    /**
-     * Perform an end-to-end post of a signed batch message
-     * @param completeBatch contains all the data of the batch including the meta-data and the signature
-     * @return a unique identifier for the batch message
-     * @throws CommunicationException
-     */
-    public MessageID postBatch(CompleteBatch completeBatch) throws CommunicationException;
-
     /**
      * Check how "safe" a given message is in a synchronous manner
      * @param id is the unique message identifier for retrieval
@@ -47,6 +39,7 @@ public interface BulletinBoardClient {
      * Note that if messages haven't been "fully posted", this might return a different
      * set of messages in different calls. However, messages that are fully posted
      * are guaranteed to be included.
+     * Also: batch messages are returned as stubs.
      * @param filterList return only messages that match the filters (null means no filtering)
      * @return the list of messages
      */
@@ -54,11 +47,11 @@ public interface BulletinBoardClient {
 
     /**
      * Read a given batch message from the bulletin board
-     * @param batchSpecificationMessage contains the data required to specify a single batch instance
+     * @param msgID is the batch message ID to be read
      * @return the complete batch
      * @throws CommunicationException
      */
-    CompleteBatch readBatch(BatchSpecificationMessage batchSpecificationMessage) throws CommunicationException;
+    BulletinBoardMessage readBatch(MessageID msgID) throws CommunicationException;
 
     /**
      * Create a SyncQuery to test against that corresponds with the current server state for a specific filter list

meerkat-common/src/main/java/meerkat/bulletinboard/BulletinBoardConstants.java

@@ -18,9 +18,4 @@ public interface BulletinBoardConstants {
     public static final String CLOSE_BATCH_PATH = "/closebatch";
     public static final String SYNC_QUERY_PATH = "/syncquery";
 
-    // Other Constants
-
-    public static final String BATCH_TAG = "@BATCH";
-    public static final String BATCH_ID_TAG_PREFIX = "BATCHID#";
-
 }

meerkat-common/src/main/java/meerkat/bulletinboard/BulletinBoardDigest.java

@@ -7,36 +7,24 @@ import java.util.List;
 
 /**
  * Created by Arbel Deutsch Peled on 18-Dec-15.
- * Extends the Digest interface with a method for digesting Batch messages
+ * Extends the Digest interface with methods for digesting Bulletin Board messages
  */
 public interface BulletinBoardDigest extends Digest {
 
     /**
-     * Update the digest with the batch message data (ignore the signature)
+     * Update the digest with the message data (ignore the signature)
      * The digest only uses the part the signatures are computed on for this operation
-     * @param completeBatch is the batch message that needs to be digested
+     * If the message is a stub: this should be called before digesting the raw data
+     * @param msg is the message that needs to be digested
      */
-    public void updateCompleteBatch(BulletinBoardMessage completeBatch);
+    public void update(BulletinBoardMessage msg);
 
     /**
-     * Update the digest with a BulletinBoardMessage that contains only the metadata of a batch message
+     * Update the digest with the message data (ignore the signature)
      * The digest only uses the part the signatures are computed on for this operation
-     * This operation is necessary before beginning to digest the actual data
+     * If the message is a stub: this should be called before digesting the raw data
-     * @param batchStub contains the metadata
+     * @param msg is the message that needs to be digested
      */
-    public void updateBatchStub(BulletinBoardMessage batchStub);
+    public void update(UnsignedBulletinBoardMessage msg);
-
-    /**
-     * Update the digest with the batch message data (ignore the signature)
-     * @param completeBatch is the batch message that needs to be digested
-     */
-    public void updateCompleteBatch(UnsignedBulletinBoardMessage completeBatch);
-
-    /**
-     * Update the digest with a BulletinBoardMessage that contains only the metadata of a batch message
-     * This operation is necessary before beginning to digest the actual data
-     * @param batchStub contains the metadata
-     */
-    public void updateBatchStub(UnsignedBulletinBoardMessage batchStub);
 
 }

meerkat-common/src/main/java/meerkat/bulletinboard/BulletinBoardServer.java

@@ -1,11 +1,11 @@
 package meerkat.bulletinboard;
 
+import com.google.protobuf.BoolValue;
+import com.google.protobuf.Int32Value;
 import meerkat.comm.CommunicationException;
 import meerkat.comm.MessageOutputStream;
 import meerkat.protobuf.BulletinBoardAPI.*;
 
-import java.util.Collection;
-
 
 /**
  * Created by Arbel on 07/11/15.
@@ -29,7 +29,7 @@ public interface BulletinBoardServer{
 	 * @return TRUE if the message has been authenticated and FALSE otherwise (in ProtoBuf form)
 	 * @throws CommunicationException on DB connection error
      */
-	public BoolMsg postMessage(BulletinBoardMessage msg) throws CommunicationException;
+	public BoolValue postMessage(BulletinBoardMessage msg) throws CommunicationException;
 
 	 /**
 	  * Read all posted messages matching the given filters
@@ -45,7 +45,7 @@ public interface BulletinBoardServer{
 	 * @return an IntMsg containing the number of messages that match the filter
 	 * @throws CommunicationException on DB connection error
 	 */
-	public IntMsg getMessageCount(MessageFilterList filterList) throws CommunicationException;
+	public Int32Value getMessageCount(MessageFilterList filterList) throws CommunicationException;
 
 	/**
 	 * Informs server about a new batch message
@@ -55,10 +55,10 @@ public interface BulletinBoardServer{
 	 * 		However, if such a batch exists and is already closed: the value returned will be FALSE
 	 * @throws CommunicationException on DB connection error
      */
-	public BoolMsg beginBatch(BeginBatchMessage message) throws CommunicationException;
+	public BoolValue beginBatch(BeginBatchMessage message) throws CommunicationException;
 
 	/**
-	 * Posts a (part of a) batch message to the bulletin board
+	 * Posts a chunk of a batch message to the bulletin board
 	 * Note that the existence and contents of a batch message are not available for reading before the batch is finalized
 	 * @param batchMessage contains the (partial) data this message carries as well as meta-data required in order to place the data
 	 *                     in the correct position inside the correct batch
@@ -66,8 +66,8 @@ public interface BulletinBoardServer{
 	 * 		Specifically, if the batch is already closed: the value returned will be FALSE
 	 * 		However, requiring to open a batch before insertion of messages is implementation-dependent
 	 * @throws CommunicationException on DB connection error
-     */
+	 */
-	public BoolMsg postBatchMessage(BatchMessage batchMessage) throws CommunicationException;
+	public BoolValue postBatchMessage(BatchMessage batchMessage) throws CommunicationException;
 
 	/**
 	 * Attempts to close and finalize a batch message
@@ -76,16 +76,16 @@ public interface BulletinBoardServer{
 	 * 		Specifically, if the signature is invalid or if some of the batch parts have not yet been submitted: the value returned will be FALSE
 	 * @throws CommunicationException on DB connection error
      */
-	public BoolMsg closeBatchMessage(CloseBatchMessage message) throws CommunicationException;
+	public BoolValue closeBatch(CloseBatchMessage message) throws CommunicationException;
 
 	/**
 	 * Reads a batch message from the server (starting with the supplied position)
-	 * @param message specifies the signer ID and the batch ID to read as well as an (optional) start position
+	 * @param batchQuery specifies which batch and what parts of it to retrieve
 	 * @param out is a stream of the ordered batch messages starting from the specified start position (if given) or from the beginning (if omitted)
 	 * @throws CommunicationException on DB connection error
-	 * @throws IllegalArgumentException if message does not specify a batch
+	 * @throws IllegalArgumentException if message ID does not specify a batch
      */
-	public void readBatch(BatchSpecificationMessage message, MessageOutputStream<BatchData> out) throws CommunicationException, IllegalArgumentException;
+	public void readBatch(BatchQuery batchQuery, MessageOutputStream<BatchChunk> out) throws CommunicationException, IllegalArgumentException;
 
 	/**
 	 * Create a SyncQuery to test against that corresponds with the current server state for a specific filter list

meerkat-common/src/main/java/meerkat/bulletinboard/BulletinBoardSignature.java

@@ -0,0 +1,31 @@
+package meerkat.bulletinboard;
+
+import meerkat.crypto.DigitalSignature;
+import meerkat.protobuf.BulletinBoardAPI.BulletinBoardMessage;
+import meerkat.protobuf.BulletinBoardAPI.UnsignedBulletinBoardMessage;
+import meerkat.protobuf.Crypto;
+
+import java.security.SignatureException;
+
+/**
+ * Created by Arbel Deutsch Peled on 18-Dec-15.
+ * Extends the DigitalSignature interface with methods for signing Bulletin Board messages
+ */
+public interface BulletinBoardSignature extends DigitalSignature {
+
+    /**
+     * Add msg to the content stream to be verified / signed
+     * The digest only uses the part the signatures are computed on for this operation
+     * If the message is a stub: this should be called before updating with the raw data
+     * @param msg is the message that needs to be digested
+     */
+    public void updateContent(BulletinBoardMessage msg) throws SignatureException;
+
+    /**
+     * Add msg to the content stream to be verified / signed
+     * If the message is a stub: this should be called before updating with the raw data
+     * @param msg is the message that needs to be digested
+     */
+    public void updateContent(UnsignedBulletinBoardMessage msg) throws SignatureException;
+
+}

meerkat-common/src/main/java/meerkat/bulletinboard/CompleteBatch.java

@@ -1,181 +0,0 @@
-package meerkat.bulletinboard;
-
-import com.google.protobuf.Timestamp;
-import meerkat.protobuf.BulletinBoardAPI.*;
-import meerkat.protobuf.Crypto.*;
-import meerkat.util.BulletinBoardUtils;
-
-import java.util.Arrays;
-import java.util.LinkedList;
-import java.util.List;
-
-/**
- * Created by Arbel Deutsch Peled on 14-Dec-15.
- *
- * A data structure for holding a complete batch message along with its signature
- */
-public class CompleteBatch {
-
-    private BeginBatchMessage beginBatchMessage;
-    private List<BatchData> batchDataList;
-    private Signature signature;
-    private Timestamp timestamp;
-
-    public CompleteBatch() {
-        batchDataList = new LinkedList<BatchData>();
-    }
-
-    public CompleteBatch(BeginBatchMessage newBeginBatchMessage) {
-        this();
-        beginBatchMessage = newBeginBatchMessage;
-    }
-
-    public CompleteBatch(BeginBatchMessage newBeginBatchMessage, List<BatchData> newDataList) {
-        this(newBeginBatchMessage);
-        appendBatchData(newDataList);
-    }
-
-    public CompleteBatch(BeginBatchMessage newBeginBatchMessage, List<BatchData> newDataList, Signature newSignature) {
-        this(newBeginBatchMessage, newDataList);
-        signature = newSignature;
-    }
-
-    public CompleteBatch(BeginBatchMessage newBeginBatchMessage, List<BatchData> newDataList, Signature newSignature, Timestamp timestamp) {
-        this(newBeginBatchMessage, newDataList, newSignature);
-        this.timestamp = timestamp;
-    }
-
-    public CompleteBatch(Timestamp timestamp) {
-        this();
-        this.timestamp = timestamp;
-    }
-
-    /**
-     * Combines the actual Bulletin board representation of a batch into a CompleteBatch object
-     * @param batchMessage is the BulletinBoard message that specifies the batch
-     * @param batchDataList is the (ordered) list of batch data
-     */
-    public CompleteBatch(BulletinBoardMessage batchMessage, List<BatchData> batchDataList) throws IllegalArgumentException{
-
-        final String[] PREFIXES = {
-                BulletinBoardConstants.BATCH_ID_TAG_PREFIX,
-                BulletinBoardConstants.BATCH_TAG};
-
-        String batchIdStr = BulletinBoardUtils.findTagWithPrefix(batchMessage, BulletinBoardConstants.BATCH_ID_TAG_PREFIX);
-
-        if (batchIdStr == null){
-            throw new IllegalArgumentException("");
-        }
-
-        this.beginBatchMessage =
-                BeginBatchMessage.newBuilder()
-                        .setSignerId(batchMessage.getSig(0).getSignerId())
-                        .setBatchId(Integer.parseInt(batchIdStr))
-                        .addAllTag(BulletinBoardUtils.removePrefixTags(batchMessage, Arrays.asList(PREFIXES)))
-                        .build();
-
-        this.batchDataList = batchDataList;
-        this.signature = batchMessage.getSig(0);
-        this.timestamp = batchMessage.getMsg().getTimestamp();
-
-    }
-
-    public BeginBatchMessage getBeginBatchMessage() {
-        return beginBatchMessage;
-    }
-
-    public List<BatchData> getBatchDataList() {
-        return batchDataList;
-    }
-
-    public Signature getSignature() {
-        return signature;
-    }
-
-    public Timestamp getTimestamp() {
-        return timestamp;
-    }
-
-    public CloseBatchMessage getCloseBatchMessage() {
-        return CloseBatchMessage.newBuilder()
-                .setBatchId(getBeginBatchMessage().getBatchId())
-                .setBatchLength(getBatchDataList().size())
-                .setSig(getSignature())
-                .setTimestamp(getTimestamp())
-                .build();
-    }
-
-    public void setBeginBatchMessage(BeginBatchMessage beginBatchMessage) {
-        this.beginBatchMessage = beginBatchMessage;
-    }
-
-    public void appendBatchData(BatchData newBatchData) {
-        batchDataList.add(newBatchData);
-    }
-
-    public void appendBatchData(List<BatchData> newBatchDataList) {
-        batchDataList.addAll(newBatchDataList);
-    }
-
-    public void setSignature(Signature newSignature) {
-        signature = newSignature;
-    }
-
-    public void setTimestamp(Timestamp timestamp) {
-        this.timestamp = timestamp;
-    }
-
-    @Override
-    public boolean equals(Object other) {
-
-        if (!(other instanceof CompleteBatch)) {
-            return false;
-        }
-
-        CompleteBatch otherBatch = (CompleteBatch) other;
-
-        boolean result = true;
-
-        if (beginBatchMessage == null) {
-            if (otherBatch.getBeginBatchMessage() != null)
-                return false;
-        } else {
-            result = result && beginBatchMessage.equals(otherBatch.getBeginBatchMessage());
-        }
-
-        if (batchDataList == null) {
-            if (otherBatch.getBatchDataList() != null)
-                return false;
-        } else {
-            result = result && batchDataList.equals(otherBatch.getBatchDataList());
-        }
-
-        if (signature == null) {
-            if (otherBatch.getSignature() != null)
-                return false;
-        } else {
-            result = result && signature.equals(otherBatch.getSignature());
-        }
-
-        if (timestamp == null) {
-            if (otherBatch.getTimestamp() != null)
-                return false;
-        } else {
-            result = result && timestamp.equals(otherBatch.getTimestamp());
-        }
-
-        return result;
-
-    }
-
-    @Override
-    public String toString() {
-
-        if (beginBatchMessage == null || beginBatchMessage.getSignerId() == null)
-            return "Unspecified batch " + super.toString();
-
-        return "Batch " + beginBatchMessage.getSignerId().toString() + ":" + beginBatchMessage.getBatchId();
-
-    }
-
-}

meerkat-common/src/main/java/meerkat/bulletinboard/DeletableBulletinBoardServer.java

@@ -1,5 +1,6 @@
 package meerkat.bulletinboard;
 
+import com.google.protobuf.BoolValue;
 import meerkat.comm.CommunicationException;
 import meerkat.protobuf.BulletinBoardAPI.*;
 
@@ -10,20 +11,22 @@ public interface DeletableBulletinBoardServer extends BulletinBoardServer {
 
     /**
      * Deletes a message from the Bulletin Board
+     * If the message is a batch: the batch data is deleted as well
      * Logs this action
      * @param msgID is the ID of the message to delete
      * @return a BoolMsg containing the value TRUE if a message was deleted, FALSE if the message does not exist
      * @throws CommunicationException in case of an error
      */
-    public BoolMsg deleteMessage(MessageID msgID) throws CommunicationException;
+    public BoolValue deleteMessage(MessageID msgID) throws CommunicationException;
 
     /**
      * Deletes a message from the Bulletin Board
+     * If the message is a batch: the batch data is deleted as well
      * Logs this action
      * @param entryNum is the serial entry number of the message to delete
      * @return a BoolMsg containing the value TRUE if a message was deleted, FALSE if the message does not exist
      * @throws CommunicationException in case of an error
      */
-    public BoolMsg deleteMessage(long entryNum) throws CommunicationException;
+    public BoolValue deleteMessage(long entryNum) throws CommunicationException;
 
 }

meerkat-common/src/main/java/meerkat/bulletinboard/GenericBatchDigitalSignature.java

@@ -1,104 +0,0 @@
-package meerkat.bulletinboard;
-
-import com.google.protobuf.ByteString;
-import com.google.protobuf.Message;
-import meerkat.crypto.DigitalSignature;
-import meerkat.protobuf.BulletinBoardAPI.BatchData;
-import meerkat.protobuf.Crypto;
-
-import java.io.IOException;
-import java.io.InputStream;
-import java.security.InvalidKeyException;
-import java.security.KeyStore;
-import java.security.KeyStoreException;
-import java.security.SignatureException;
-import java.security.NoSuchAlgorithmException;
-import java.security.UnrecoverableKeyException;
-import java.security.cert.CertificateException;
-
-/**
- * Created by Arbel Deutsch Peled on 20-Dec-15.
- * Wrapper class for signing and verifying Batch signatures in a standardized way
- */
-public class GenericBatchDigitalSignature implements BatchDigitalSignature{
-
-    private DigitalSignature digitalSignature;
-
-    public GenericBatchDigitalSignature(DigitalSignature digitalSignature) {
-        this.digitalSignature = digitalSignature;
-    }
-
-    @Override
-    public void updateContent(CompleteBatch completeBatch) throws SignatureException {
-
-        digitalSignature.updateContent(completeBatch.getBeginBatchMessage());
-
-        for (BatchData batchData : completeBatch.getBatchDataList()) {
-            digitalSignature.updateContent(batchData);
-        }
-
-        digitalSignature.updateContent(completeBatch.getTimestamp());
-
-    }
-
-    @Override
-    public boolean verify(CompleteBatch completeBatch) throws SignatureException, CertificateException, InvalidKeyException {
-
-        digitalSignature.initVerify(completeBatch.getSignature());
-        updateContent(completeBatch);
-        return digitalSignature.verify();
-
-    }
-
-    @Override
-    public void loadVerificationCertificates(InputStream certStream) throws CertificateException {
-        digitalSignature.loadVerificationCertificates(certStream);
-    }
-
-    @Override
-    public void clearVerificationCertificates() {
-        digitalSignature.clearVerificationCertificates();
-    }
-
-    @Override
-    public void updateContent(Message msg) throws SignatureException {
-        digitalSignature.updateContent(msg);
-    }
-
-    @Override
-    public Crypto.Signature sign() throws SignatureException {
-        return digitalSignature.sign();
-    }
-
-    @Override
-    public void initVerify(Crypto.Signature sig) throws CertificateException, InvalidKeyException {
-        digitalSignature.initVerify(sig);
-    }
-
-    @Override
-    public boolean verify() {
-        return digitalSignature.verify();
-    }
-
-    @Override
-    public KeyStore.Builder getPKCS12KeyStoreBuilder(InputStream keyStream, char[] password)
-            throws IOException, CertificateException, KeyStoreException, NoSuchAlgorithmException {
-        return digitalSignature.getPKCS12KeyStoreBuilder(keyStream, password);
-    }
-
-    @Override
-    public void loadSigningCertificate(KeyStore.Builder keyStoreBuilder) throws IOException, CertificateException, UnrecoverableKeyException {
-        digitalSignature.loadSigningCertificate(keyStoreBuilder);
-    }
-
-    @Override
-    public ByteString getSignerID() {
-        return digitalSignature.getSignerID();
-    }
-
-    @Override
-    public void clearSigningKey() {
-        digitalSignature.clearSigningKey();
-    }
-
-}

meerkat-common/src/main/java/meerkat/bulletinboard/GenericBulletinBoardDigest.java

@@ -1,5 +1,6 @@
 package meerkat.bulletinboard;
 
+import com.google.protobuf.ByteString;
 import com.google.protobuf.BytesValue;
 import com.google.protobuf.Message;
 import meerkat.crypto.Digest;
@@ -51,29 +52,23 @@ public class GenericBulletinBoardDigest implements BulletinBoardDigest {
     }
 
     @Override
-    public void updateCompleteBatch(BulletinBoardMessage completeBatch) {
+    public void update(BulletinBoardMessage msg) {
-        updateCompleteBatch(completeBatch.getMsg());
+        update(msg.getMsg());
     }
 
     @Override
-    public void updateBatchStub(BulletinBoardMessage batchStub) {
+    public void update(UnsignedBulletinBoardMessage msg) {
-        updateBatchStub(batchStub.getMsg());
-    }
 
-    @Override
+        for (ByteString tag : msg.getTagList().asByteStringList()){
-    public void updateCompleteBatch(UnsignedBulletinBoardMessage completeBatch) {
+            update(tag.toByteArray());
+        }
 
-        // Digest just the signed part
+        update(msg.getTimestamp());
-        UnsignedBulletinBoardMessage batchStub = completeBatch.toBuilder().clearData().build();
-        updateBatchStub(batchStub);
 
-        // Digest the data
+        if (!msg.getIsStub()){
-        update(completeBatch.getData().toByteArray());
+            update(msg.getData().toByteArray());
+        }
 
     }
 
-    @Override
-    public void updateBatchStub(UnsignedBulletinBoardMessage batchStub) {
-        update(batchStub);
-    }
 }

meerkat-common/src/main/java/meerkat/bulletinboard/GenericBulletinBoardSignature.java

@@ -0,0 +1,106 @@
+package meerkat.bulletinboard;
+
+import com.google.protobuf.ByteString;
+import com.google.protobuf.Message;
+import meerkat.crypto.Digest;
+import meerkat.crypto.DigitalSignature;
+import meerkat.protobuf.BulletinBoardAPI;
+import meerkat.protobuf.BulletinBoardAPI.BulletinBoardMessage;
+import meerkat.protobuf.BulletinBoardAPI.MessageID;
+import meerkat.protobuf.BulletinBoardAPI.UnsignedBulletinBoardMessage;
+import meerkat.protobuf.Crypto;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.security.*;
+import java.security.cert.CertificateException;
+
+
+/**
+ * Created by Arbel Deutsch Peled on 19-Dec-15.
+ * Wrapper class for digesting Batches in a standardized way
+ */
+public class GenericBulletinBoardSignature implements BulletinBoardSignature {
+
+    private DigitalSignature signer;
+
+    public GenericBulletinBoardSignature(DigitalSignature signer) {
+        this.signer = signer;
+    }
+
+    @Override
+    public void updateContent(BulletinBoardMessage msg) throws SignatureException{
+        signer.updateContent(msg.getMsg());
+    }
+
+    @Override
+    public void updateContent(UnsignedBulletinBoardMessage msg) throws SignatureException{
+
+        for (ByteString tag : msg.getTagList().asByteStringList()){
+            updateContent(tag.toByteArray());
+        }
+
+        updateContent(msg.getTimestamp());
+
+        if (!msg.getIsStub()){
+            updateContent(msg.getData().toByteArray());
+        }
+
+    }
+
+    @Override
+    public void loadVerificationCertificates(InputStream certStream) throws CertificateException {
+        signer.loadVerificationCertificates(certStream);
+    }
+
+    @Override
+    public void clearVerificationCertificates() {
+        signer.clearVerificationCertificates();
+    }
+
+    @Override
+    public void updateContent(byte[] data) throws SignatureException {
+        signer.updateContent(data);
+    }
+
+    @Override
+    public void updateContent(Message msg) throws SignatureException {
+        signer.updateContent(msg);
+    }
+
+    @Override
+    public Crypto.Signature sign() throws SignatureException {
+        return signer.sign();
+    }
+
+    @Override
+    public void initVerify(Crypto.Signature sig) throws CertificateException, InvalidKeyException {
+        signer.initVerify(sig);
+    }
+
+    @Override
+    public boolean verify() {
+        return signer.verify();
+    }
+
+    @Override
+    public KeyStore.Builder getPKCS12KeyStoreBuilder(InputStream keyStream, char[] password) throws IOException, CertificateException, KeyStoreException, NoSuchAlgorithmException {
+        return signer.getPKCS12KeyStoreBuilder(keyStream, password);
+    }
+
+    @Override
+    public void loadSigningCertificate(KeyStore.Builder keyStoreBuilder) throws IOException, CertificateException, UnrecoverableKeyException {
+        signer.loadSigningCertificate(keyStoreBuilder);
+    }
+
+    @Override
+    public ByteString getSignerID() {
+        return signer.getSignerID();
+    }
+
+    @Override
+    public void clearSigningKey() {
+        signer.clearSigningKey();
+    }
+
+}

meerkat-common/src/main/java/meerkat/comm/Channel.java

@@ -0,0 +1,42 @@
+package meerkat.comm;
+
+import com.google.protobuf.Message;
+import meerkat.protobuf.Comm;
+
+/**
+ * A generic communication channel that supports point-to-point and broadcast operation
+ */
+
+public interface Channel {
+    /**
+     * Return the id of the channel's endpoint (this will be used as the source of message sent from the channel).
+     * @return
+     */
+    public int getSourceId();
+
+    public interface ReceiverCallback {
+        public void receiveMessage(Comm.BroadcastMessage envelope);
+    }
+
+    /**
+     * sends a private message
+     * @param destUser destination user's identifier
+     * @param msg message
+     */
+    public void sendMessage(int destUser, Message msg);
+
+
+    /**
+     * broadcasts a message to all parties (including the sender)
+     * @param msg message
+     */
+    public void broadcastMessage(Message msg);
+
+    /**
+     * Register a callback to handle received messages.
+     * The callback is called in the <b>Channel</b> thread, so no long processing should
+     * occur in the callback method.
+     * @param callback
+     */
+    public void registerReceiverCallback(ReceiverCallback callback);
+}

meerkat-common/src/main/java/meerkat/crypto/DigitalSignature.java

@@ -39,6 +39,13 @@ public interface DigitalSignature {
      */
     public void clearVerificationCertificates();
 
+    /**
+     * Add raw data to the content stream to be verified / signed.
+     *
+     * @param data
+     * @throws SignatureException
+     */
+    public void updateContent(byte[] data) throws SignatureException;
 
     /**
      * Add msg to the content stream to be verified / signed. Each message is (automatically)

meerkat-common/src/main/java/meerkat/crypto/concrete/ECDSASignature.java

@@ -140,6 +140,11 @@ public class ECDSASignature implements DigitalSignature {
         signer.update(msg.toByteString().asReadOnlyByteBuffer());
     }
 
+    @Override
+    public void updateContent(byte[] data) throws SignatureException {
+        signer.update(data);
+    }
+
     public void updateContent(InputStream in) throws IOException, SignatureException {
         ByteString inStr = ByteString.readFrom(in);
         signer.update(inStr.asReadOnlyByteBuffer());

meerkat-common/src/main/java/meerkat/crypto/concrete/ECElGamalEncryption.java

@@ -113,7 +113,7 @@ public class ECElGamalEncryption implements Encryption {
         Pair<ECPoint,ECPoint> randomizer = elGamalPK.encrypt(curve.getInfinity(), rndInt);
         ConcreteCrypto.ElGamalCiphertext originalEncodedCipher= ConcreteCrypto.ElGamalCiphertext.parseFrom(msg.getData());
 
-        Pair<ECPoint,ECPoint> originalCipher = new Pair<>(
+        Pair<ECPoint,ECPoint> originalCipher = new Pair<ECPoint, ECPoint>(
                 curve.decodePoint(originalEncodedCipher.getC1().toByteArray()),
                 curve.decodePoint(originalEncodedCipher.getC2().toByteArray()));
         Pair<ECPoint,ECPoint> newCipher = elGamalPK.add(originalCipher, randomizer);

meerkat-common/src/main/java/meerkat/pollingstation/PollingStationConstants.java

@@ -0,0 +1,13 @@
+package meerkat.pollingstation;
+
+/**
+ * Created by Arbel Deutsch Peled on 21-Dec-15.
+ */
+public interface PollingStationConstants {
+
+    // Relative addresses for Scanner operations
+
+    public static final String POLLING_STATION_WEB_SCANNER_SCAN_PATH = "/scan";
+    public static final String POLLING_STATION_WEB_SCANNER_ERROR_PATH = "/error";
+
+}

meerkat-common/src/main/java/meerkat/pollingstation/PollingStationScanner.java

@@ -0,0 +1,61 @@
+package meerkat.pollingstation;
+
+import com.google.common.util.concurrent.FutureCallback;
+import com.google.protobuf.BoolValue;
+import meerkat.protobuf.PollingStation.*;
+/**
+ * Created by Arbel on 05/05/2016.
+ * An interface for the scanner used by the Polling Station Committee
+ * The scanner works as a producer, while the polling station is the consumer
+ * That is to say: scans are pushed from the scanner rather than requested by the polling station
+ */
+public interface PollingStationScanner {
+
+    /**
+     * An interface for processing scans (Polling Station side)
+     */
+    public interface Consumer {
+
+        /**
+         * Sets up the connection to the scanner and begins receiving scans
+         * @throws Exception when the operation fails
+         */
+        public void start() throws Exception;
+
+        /**
+         * Closes the connection to the scanner
+         * @throws Exception when the operation fails
+         */
+        public void stop() throws Exception;
+
+        /**
+         * Subscribes to new scans
+         *
+         * @param scanCallback is the handler for scanned data
+         */
+        public void subscribe(FutureCallback<ScannedData> scanCallback);
+
+    }
+
+    /**
+     * An interface for submitting scanned data (scanner side)
+     */
+    public interface Producer {
+
+        /**
+         * Sends a scan to all subscribers
+         * @param scannedData contains the scanned data
+         * @return a BoolValue containing TRUE iff the scanned data has been sent to at least one subscriber
+         */
+        public BoolValue newScan(ScannedData scannedData);
+
+        /**
+         * Notifies subscribers about an error that occurred during scan
+         * @param errorMsg is the error that occurred
+         * @return a BoolValue containing TRUE iff the error has been sent to at least one subscriber
+         */
+        public BoolValue reportScanError(ErrorMsg errorMsg);
+
+    }
+    
+}

meerkat-common/src/main/java/meerkat/util/BulletinBoardMessageComparator.java

@@ -5,6 +5,7 @@ import meerkat.protobuf.BulletinBoardAPI.*;
 import meerkat.protobuf.Crypto.*;
 
 import java.util.Comparator;
+import java.util.Iterator;
 import java.util.List;
 
 /**
@@ -24,22 +25,51 @@ public class BulletinBoardMessageComparator implements Comparator<BulletinBoardM
     @Override
     public int compare(BulletinBoardMessage msg1, BulletinBoardMessage msg2) {
 
-        List<Signature> msg1Sigs = msg1.getSigList();
-        List<Signature> msg2Sigs = msg2.getSigList();
 
-        // Compare unsigned message
+
-        if (!msg1.getMsg().equals(msg2.getMsg())){
+        // Compare Timestamps
+
+        if (!msg1.getMsg().getTimestamp().equals(msg2.getMsg().getTimestamp())){
             return -1;
         }
 
-        // Compare signatures
+        // Compare tags (enforce order)
 
-        if (msg1Sigs.size() != msg2Sigs.size()){
+        List<String> tags1 = msg1.getMsg().getTagList();
+        Iterator<String> tags2 = msg2.getMsg().getTagList().iterator();
+
+        for (String tag : tags1){
+            if (!tags2.hasNext()) {
+                return -1;
+            }
+            if (!tags2.next().equals(tag)){
+                return -1;
+            }
+        }
+
+        // Compare data (only for non-stub messages)
+
+        if (msg1.getMsg().getIsStub() != msg2.getMsg().getIsStub()){
             return -1;
         }
 
-        for (Signature sig : msg1Sigs){
+        if (msg1.getMsg().getIsStub()){
-            if (!msg2Sigs.contains(sig)) {
+            if (!msg1.getMsg().getData().equals(msg2.getMsg().getData())){
+                return -1;
+            }
+        }
+
+        // Compare signatures (do not enforce order)
+
+        List<Signature> sigs1 = msg1.getSigList();
+        List<Signature> sigs2 = msg2.getSigList();
+
+        if (sigs1.size() != sigs2.size()){
+            return -1;
+        }
+
+        for (Signature sig : sigs1){
+            if (!sigs2.contains(sig)) {
                 return -1;
             }
         }

meerkat-common/src/main/java/meerkat/util/BulletinBoardMessageGenerator.java

@@ -1,8 +1,6 @@
 package meerkat.util;
 
 import com.google.protobuf.ByteString;
-import meerkat.bulletinboard.BatchDigitalSignature;
-import meerkat.bulletinboard.CompleteBatch;
 import meerkat.crypto.DigitalSignature;
 import meerkat.protobuf.BulletinBoardAPI.*;
 import com.google.protobuf.Timestamp;
@@ -131,97 +129,4 @@ public class BulletinBoardMessageGenerator {
 
     }
 
-    /**
-     * Generates a complete instance of a CompleteBatch
-     * @param signer contains the credentials required to sign the message
-     * @param batchId is the (per-signer) batch-ID
-     * @param timestamp is the time at which the message was generated
-     * @param dataCount is the number of Batch Data in the batch
-     * @param dataSize is the number of bytes per Batch Data
-     * @param tagCount is the number of tags
-     * @param tags contains a list of tags to be added (in addition to the random ones)
-     * @return a random, signed CompleteBatch containing random data and tags
-     * @throws SignatureException if an error occurs while signing the batch
-     */
-    public CompleteBatch generateRandomBatch(BatchDigitalSignature signer, int batchId, Timestamp timestamp, int dataCount, int dataSize, int tagCount, List<String> tags) throws SignatureException {
-
-        CompleteBatch result = new CompleteBatch(BeginBatchMessage.newBuilder()
-                .setSignerId(signer.getSignerID())
-                .setBatchId(batchId)
-                .addAllTag(tags)
-                .addAllTag(randomStrings(tagCount))
-                .build());
-
-        List<BatchData> batchDataList = new LinkedList<>();
-
-        for (int i = 0 ; i < dataCount ; i++) {
-            batchDataList.add(BatchData.newBuilder()
-                    .setData(ByteString.copyFrom(randomBytes(dataSize)))
-                    .build());
-        }
-
-        result.appendBatchData(batchDataList);
-
-        result.setTimestamp(timestamp);
-
-        signer.updateContent(result);
-
-        result.setSignature(signer.sign());
-
-        return result;
-
-    }
-
-    /**
-     * Generates a complete instance of a CompleteBatch
-     * @param signer contains the credentials required to sign the message
-     * @param batchId is the (per-signer) batch-ID
-     * @param timestamp is the time at which the message was generated
-     * @param dataCount is the number of Batch Data in the batch
-     * @param dataSize is the number of bytes per Batch Data
-     * @param tagCount is the number of tags
-     * @return a random, signed CompleteBatch containing random data and tags
-     * @throws SignatureException if an error occurs while signing the batch
-     */
-    public CompleteBatch generateRandomBatch(BatchDigitalSignature signer, int batchId, Timestamp timestamp, int dataCount, int dataSize, int tagCount) throws SignatureException {
-        return generateRandomBatch(signer, batchId, timestamp, dataCount, dataSize, tagCount, new LinkedList<String>());
-    }
-
-
-    /**
-     * Generates a complete instance of a CompleteBatch
-     * @param signer contains the credentials required to sign the message
-     * @param batchId is the (per-signer) batch-ID
-     * @param dataCount is the number of Batch Data in the batch
-     * @param dataSize is the number of bytes per Batch Data
-     * @param tagCount is the number of tags
-     * @param tags contains a list of tags to be added (in addition to the random ones)
-     * @return a random, signed CompleteBatch containing random data, tags and timestamp
-     * @throws SignatureException if an error occurs while signing the batch
-     */
-    public CompleteBatch generateRandomBatch(BatchDigitalSignature signer, int batchId, int dataCount, int dataSize, int tagCount, List<String> tags) throws SignatureException {
-
-        Timestamp timestamp = Timestamp.newBuilder()
-                .setSeconds(random.nextLong())
-                .setNanos(random.nextInt())
-                .build();
-
-        return generateRandomBatch(signer, batchId, timestamp, dataCount, dataSize, tagCount, tags);
-
-    }
-
-    /**
-     * Generates a complete instance of a CompleteBatch
-     * @param signer contains the credentials required to sign the message
-     * @param batchId is the (per-signer) batch-ID
-     * @param dataCount is the number of Batch Data in the batch
-     * @param dataSize is the number of bytes per Batch Data
-     * @param tagCount is the number of tags
-     * @return a random, signed CompleteBatch containing random data, tags and timestamp
-     * @throws SignatureException if an error occurs while signing the batch
-     */
-    public CompleteBatch generateRandomBatch(BatchDigitalSignature signer, int batchId, int dataCount, int dataSize, int tagCount) throws SignatureException {
-        return generateRandomBatch(signer, batchId, dataCount, dataSize, tagCount, new LinkedList<String>());
-    }
-
 }

meerkat-common/src/main/java/meerkat/util/BulletinBoardUtils.java

@@ -1,7 +1,9 @@
 package meerkat.util;
 
+import com.google.protobuf.ByteString;
 import meerkat.protobuf.BulletinBoardAPI.*;
 
+import java.util.ArrayList;
 import java.util.LinkedList;
 import java.util.List;
 
@@ -104,4 +106,150 @@ public class BulletinBoardUtils {
         return new java.sql.Timestamp(protoTimestamp.getSeconds() * 1000 + protoTimestamp.getNanos() / 1000000);
     }
 
+    /**
+     * Breaks up a bulletin board message into chunks
+     * @param msg is the complete message
+     * @return a list of BatchChunks that contains the raw message data
+     */
+    public static List<BatchChunk> breakToBatch(BulletinBoardMessage msg, int chunkSize) {
+
+        byte[] data = msg.getMsg().getData().toByteArray();
+
+        int chunkNum = data.length / chunkSize;
+        if (data.length % chunkSize != 0)
+            chunkNum++;
+
+        List<BatchChunk> chunkList = new ArrayList<>(chunkNum);
+
+        int location = 0;
+
+        for (int i=0 ; i < chunkNum ; i++) {
+
+            int chunkLength;
+
+            if (i == chunkNum - 1){
+                chunkLength = data.length % chunkSize;
+                if (chunkLength == 0){
+                    chunkLength = chunkSize;
+                }
+            } else{
+                chunkLength = chunkSize;
+            }
+
+            chunkList.add(BatchChunk.newBuilder()
+                    .setData(ByteString.copyFrom(data, location, chunkLength))
+                    .build());
+
+            location += chunkLength;
+
+        }
+
+        return chunkList;
+
+    }
+
+    /**
+     * Removes concrete data from the message and turns it into a stub
+     * @param msg is the original message
+     * @return the message stub
+     */
+    public static BulletinBoardMessage makeStub(BulletinBoardMessage msg) {
+
+        return BulletinBoardMessage.newBuilder()
+                .mergeFrom(msg)
+                .setMsg(UnsignedBulletinBoardMessage.newBuilder().
+                        mergeFrom(msg.getMsg())
+                        .setIsStub(true)
+                        .clearData()
+                        .build())
+                .build();
+
+    }
+
+    /**
+     * Merges a batch chunk list back into a message stub to create a complete Bulletin Board message
+     * @param msgStub is a message stub
+     * @param chunkList contains the (ordered) data of the batch message
+     * @return a complete message containing both data and metadata
+     */
+    public static BulletinBoardMessage gatherBatch(BulletinBoardMessage msgStub, List<BatchChunk> chunkList) {
+
+        List<ByteString> dataList = new LinkedList<>();
+
+        for (BatchChunk chunk : chunkList){
+            dataList.add(chunk.getData());
+        }
+
+        return BulletinBoardMessage.newBuilder()
+                .mergeFrom(msgStub)
+                .setMsg(UnsignedBulletinBoardMessage.newBuilder().
+                        mergeFrom(msgStub.getMsg())
+                        .setIsStub(false)
+                        .setData(ByteString.copyFrom(dataList))
+                        .build())
+                .build();
+
+    }
+
+    /**
+     * Gerenates a BeginBatchMessage Protobuf which is used to begin uploading a message as a batch
+     * @param signerId is the ID of the message generator
+     * @param batchId is the identifier for the message
+     * @param msg is the Bulletin Board message to be uploaded, which can be a stub or a complete message
+     * @return the required BeginBatchMessage
+     */
+    public static BeginBatchMessage generateBeginBatchMessage(ByteString signerId, int batchId, BulletinBoardMessage msg) {
+
+        if (msg.getSigCount() <= 0){
+            throw new IllegalArgumentException("No signatures found");
+        }
+
+        return BeginBatchMessage.newBuilder()
+                .setSignerId(signerId)
+                .setBatchId(batchId)
+                .addAllTag(msg.getMsg().getTagList())
+                .build();
+
+    }
+
+    /**
+     * Gerenates a BeginBatchMessage Protobuf which is used to begin uploading a message as a batch
+     * @param batchId is the identifier for the message
+     * @param msg is the Bulletin Board message to be uploaded, which can be a stub or a complete message
+     *            The signer ID used will be the one from the first signature in the message
+     * @return the required BeginBatchMessage
+     * @throws IllegalArgumentException if the message contains no signatures
+     */
+    public static BeginBatchMessage generateBeginBatchMessage(int batchId, BulletinBoardMessage msg) throws IllegalArgumentException {
+
+        if (msg.getSigCount() <= 0){
+            throw new IllegalArgumentException("No signatures found");
+        }
+
+        return generateBeginBatchMessage(msg.getSig(0).getSignerId(), batchId, msg);
+
+    }
+
+    /**
+     * Gerenates a CloseBatchMessage Protobuf which is used to finalize a batch message
+     * @param batchId is the identifier for the message
+     * @param batchLength is the number of chunks in the batch
+     * @param msg is the Bulletin Board message that was uploaded (and can also be a stub of said message)
+     * @throws IllegalArgumentException if the message contains no signatures
+     */
+    public static CloseBatchMessage generateCloseBatchMessage(int batchId, int batchLength, BulletinBoardMessage msg) {
+
+        if (msg.getSigCount() <= 0){
+            throw new IllegalArgumentException("No signatures found");
+        }
+
+        return CloseBatchMessage.newBuilder()
+                .setTimestamp(msg.getMsg().getTimestamp())
+                .setBatchLength(batchLength)
+                .setBatchId(batchId)
+                .addAllSig(msg.getSigList())
+                .build();
+
+    }
+
 }

meerkat-common/src/main/proto/meerkat/BulletinBoardAPI.proto

@@ -7,14 +7,6 @@ option java_package = "meerkat.protobuf";
 import 'meerkat/crypto.proto';
 import 'google/protobuf/timestamp.proto';
 
-message BoolMsg {
-    bool value = 1;
-}
-
-message IntMsg {
-    int32 value = 1;
-}
-
 message MessageID {
 	// The ID of a message for unique retrieval.
 	// Note that it is assumed that this ID is a function of the message itself.
@@ -28,15 +20,19 @@ message UnsignedBulletinBoardMessage {
     // Timestamp of the message (as defined by client)
     google.protobuf.Timestamp timestamp = 2;
 
+    // Defines whether or not the message is a stub
+    // If the message is a stub: the data is ignored
+    bool isStub = 3;
+
     // The actual content of the message
-    bytes data = 3;
+    bytes data = 4;
 }
 
 message BulletinBoardMessage {
 	
 	// Serial entry number of message in database
 	int64 entryNum = 1;
-	
+
 	// Unsigned raw data of message
     UnsignedBulletinBoardMessage msg = 2;
 
@@ -90,7 +86,7 @@ message MessageFilterList {
 
 // This message is used to start a batch transfer to the Bulletin Board Server
 message BeginBatchMessage {
-    bytes signerId = 1;             // Unique signer identifier
+    bytes signerId = 1;             // Unique identifier of the main signer of the message
     int32 batchId = 2;              // Unique identifier for the batch (unique per signer)
     repeated string tag = 3;        // Tags for the batch message
 }
@@ -100,17 +96,17 @@ message CloseBatchMessage {
     int32 batchId = 1;                          // Unique identifier for the batch (unique per signer)
     int32 batchLength = 2;                      // Number of messages in the batch
     google.protobuf.Timestamp timestamp = 3;    // Timestamp of the batch (as defined by client)
-    meerkat.Signature sig = 4;                  // Signature on the (ordered) batch messages
+    repeated meerkat.Signature sig = 4;         // Signature on the (ordered) batch messages ; First signature belongs to main signer
 }
 
-// Container for single batch message data
+// Container for single chunk of abatch message
-message BatchData {
+message BatchChunk {
     bytes data = 1;
 }
 
-// List of BatchData; Only used for testing
+// List of BatchChunk; Only used for testing
-message BatchDataList {
+message BatchChunkList {
-    repeated BatchData data = 1;
+    repeated BatchChunk data = 1;
 }
 
 // These messages comprise a batch message
@@ -118,14 +114,7 @@ message BatchMessage {
     bytes signerId = 1;             // Unique signer identifier
     int32 batchId = 2;              // Unique identifier for the batch (unique per signer)
     int32 serialNum = 3;            // Location of the message in the batch: starting from 0
-    BatchData data = 4;             // Actual data
+    BatchChunk data = 4;             // Actual data
-}
-
-// This message defines which batch to read and from which location to start reading
-message BatchSpecificationMessage {
-    bytes signerId = 1;             // Unique signer identifier
-    int32 batchId = 2;              // Unique identifier for the batch (unique per signer)
-    int32 startPosition = 3;        // Position in batch to start reading from
 }
 
 // This message is used to define a single query to the server to ascertain whether or not the server is synched with the client
@@ -168,4 +157,15 @@ message SyncQueryResponse {
     // Largest value of timestamp for which the checksums match
     google.protobuf.Timestamp lastTimeOfSync = 2;
 
+}
+
+// This message defines a query for retrieval of batch data
+message BatchQuery {
+
+    // The unique message ID if the batch
+    MessageID msgID = 1;
+
+    // The first chunk to retrieve (0 is the first chunk)
+    int32 startPosition = 2;
+
 }

meerkat-common/src/main/proto/meerkat/PollingStation.proto

@@ -0,0 +1,15 @@
+syntax = "proto3";
+
+package meerkat;
+
+option java_package = "meerkat.protobuf";
+
+// Container for scanned data
+message ScannedData {
+    bytes data = 1;
+}
+
+// Container for error messages
+message ErrorMsg {
+    string msg = 1;
+}

meerkat-common/src/main/proto/meerkat/comm.proto

@@ -0,0 +1,13 @@
+syntax = "proto3";
+
+package meerkat;
+
+option java_package = "meerkat.protobuf";
+
+message BroadcastMessage {
+    int32 sender = 1;
+    int32 destination = 2;
+    bool is_private = 3;
+
+    bytes payload = 5;
+}

meerkat-common/src/test/java/meerkat/bulletinboard/BulletinBoardDigestTest.java

@@ -0,0 +1,112 @@
+package meerkat.bulletinboard;
+
+import com.google.protobuf.ByteString;
+import meerkat.crypto.concrete.ECDSASignature;
+import meerkat.crypto.concrete.SHA256Digest;
+import meerkat.protobuf.BulletinBoardAPI.*;
+import meerkat.util.BulletinBoardMessageGenerator;
+import meerkat.util.BulletinBoardUtils;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.security.*;
+import java.security.cert.CertificateException;
+import java.util.List;
+import java.util.Random;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.junit.Assert.fail;
+
+/**
+ * Created by Arbel Deutsch Peled on 16-Jun-16.
+ */
+public class BulletinBoardDigestTest {
+
+    private static String KEYFILE_EXAMPLE = "/certs/enduser-certs/user1-key-with-password-secret.p12";
+    private static String KEYFILE_EXAMPLE3 = "/certs/enduser-certs/user3-key-with-password-shh.p12";
+
+    private static String KEYFILE_PASSWORD1 = "secret";
+    private static String KEYFILE_PASSWORD3 = "shh";
+
+    private GenericBulletinBoardSignature[] signers;
+    private ByteString[] signerIDs;
+
+    @Before
+    public void init() {
+
+        signers = new GenericBulletinBoardSignature[2];
+        signerIDs = new ByteString[signers.length];
+        signers[0] = new GenericBulletinBoardSignature(new ECDSASignature());
+        signers[1] = new GenericBulletinBoardSignature(new ECDSASignature());
+
+        InputStream keyStream = getClass().getResourceAsStream(KEYFILE_EXAMPLE);
+        char[] password = KEYFILE_PASSWORD1.toCharArray();
+
+        KeyStore.Builder keyStoreBuilder = null;
+        try {
+            keyStoreBuilder = signers[0].getPKCS12KeyStoreBuilder(keyStream, password);
+
+            signers[0].loadSigningCertificate(keyStoreBuilder);
+
+            keyStream = getClass().getResourceAsStream(KEYFILE_EXAMPLE3);
+            password = KEYFILE_PASSWORD3.toCharArray();
+
+            keyStoreBuilder = signers[1].getPKCS12KeyStoreBuilder(keyStream, password);
+            signers[1].loadSigningCertificate(keyStoreBuilder);
+
+            for (int i = 0 ; i < signers.length ; i++) {
+                signerIDs[i] = signers[i].getSignerID();
+            }
+
+        } catch (IOException e) {
+            System.err.println("Failed reading from signature file " + e.getMessage());
+            fail("Failed reading from signature file " + e.getMessage());
+        } catch (CertificateException e) {
+            System.err.println("Failed reading certificate " + e.getMessage());
+            fail("Failed reading certificate " + e.getMessage());
+        } catch (KeyStoreException e) {
+            System.err.println("Failed reading keystore " + e.getMessage());
+            fail("Failed reading keystore " + e.getMessage());
+        } catch (NoSuchAlgorithmException e) {
+            System.err.println("Couldn't find signing algorithm " + e.getMessage());
+            fail("Couldn't find signing algorithm " + e.getMessage());
+        } catch (UnrecoverableKeyException e) {
+            System.err.println("Couldn't find signing key " + e.getMessage());
+            fail("Couldn't find signing key " + e.getMessage());
+        }
+
+    }
+
+    @Test
+    public void testBatchDigest() throws SignatureException {
+
+        final int MESSAGE_SIZE = 100;
+        final int CHUNK_SIZE = 10;
+        final int TAG_NUM = 10;
+
+        BulletinBoardMessageGenerator generator = new BulletinBoardMessageGenerator(new Random(0));
+
+        BulletinBoardMessage completeMessage = generator.generateRandomMessage(signers, MESSAGE_SIZE, TAG_NUM);
+
+        BulletinBoardMessage stub = BulletinBoardUtils.makeStub(completeMessage);
+        List<BatchChunk> batchChunks = BulletinBoardUtils.breakToBatch(completeMessage, CHUNK_SIZE);
+
+        BulletinBoardDigest digest = new GenericBulletinBoardDigest(new SHA256Digest());
+
+        digest.update(completeMessage);
+        MessageID id1 = digest.digestAsMessageID();
+
+        digest.update(stub);
+        for (BatchChunk batchChunk : batchChunks){
+            digest.update(batchChunk.getData().toByteArray());
+        }
+
+        MessageID id2 = digest.digestAsMessageID();
+
+        assertThat("Digests not equal!", id1.getID().equals(id2.getID()));
+
+    }
+
+}

meerkat-common/src/test/java/meerkat/comm/ChannelImpl.java

@@ -0,0 +1,96 @@
+package meerkat.comm;
+
+import com.google.protobuf.Message;
+import com.google.protobuf.TextFormat;
+import meerkat.protobuf.Comm;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Queue;
+import java.util.TreeMap;
+import java.util.concurrent.*;
+
+/**
+ * Created by Tzlil on 2/14/2016.
+ */
+// TODO: Change nane to network
+
+public class ChannelImpl  {
+    final Logger logger = LoggerFactory.getLogger(getClass());
+
+    //private ExecutorService executorService = Executors.newCachedThreadPool();
+    public static int BROADCAST = 0;
+    Map<Integer,SingleChannel> channels = new TreeMap<>();
+
+
+    public ChannelImpl() {
+    }
+
+    public Channel getChannel(int id) {
+        return new SingleChannel(id);
+    }
+
+    public class SingleChannel implements Channel {
+        protected final int id;
+
+        ReceiverCallback callback;
+
+        SingleChannel(int id) {
+            this.id = id;
+            channels.put(id, this);
+        }
+
+        @Override
+        public int getSourceId() {
+            return id;
+        }
+
+
+        @Override
+        public void sendMessage(int destUser, Message msg) {
+            if (destUser < 1)
+                return;
+            SingleChannel channel = channels.get(destUser);
+            if (channel == null) {
+                logger.warn("Party {} attempting to send message to non-existing party {}", getSourceId(), destUser);
+                return;
+            }
+            Comm.BroadcastMessage broadcastMessage = Comm.BroadcastMessage.newBuilder()
+                    .setSender(id)
+                    .setDestination(destUser)
+                    .setIsPrivate(true)
+                    .setPayload(msg.toByteString())
+                    .build();
+
+            logger.debug("sending Message: Dst={},Src={} [{}]", broadcastMessage.getDestination(),
+                    broadcastMessage.getSender(), TextFormat.printToString(msg));
+
+            channel.callback.receiveMessage(broadcastMessage);
+        }
+
+        @Override
+        public void broadcastMessage(Message msg) {
+            Comm.BroadcastMessage broadcastMessage = Comm.BroadcastMessage.newBuilder()
+                    .setSender(id)
+                    .setDestination(BROADCAST)
+                    .setIsPrivate(false)
+                    .setPayload(msg.toByteString())
+                    .build();
+
+            logger.debug("broadcasting Message: Src={} [{}]",
+                    broadcastMessage.getSender(), TextFormat.printToString(msg));
+
+            for (SingleChannel channel : channels.values()) {
+                channel.callback.receiveMessage(broadcastMessage);
+            }
+        }
+
+        @Override
+        public void registerReceiverCallback(final ReceiverCallback callback) {
+            this.callback = callback;
+        }
+    }
+
+}

meerkat-common/src/test/java/meerkat/crypto/concrete/ECDSADeterministicSignatureTest.java

@@ -3,7 +3,6 @@ package meerkat.crypto.concrete;
 import com.google.protobuf.ByteString;
 import com.google.protobuf.Message;
 
-import meerkat.crypto.concrete.ECDSASignature;
 import meerkat.protobuf.Crypto;
 import org.junit.Test;
 

meerkat-common/src/test/java/meerkat/crypto/concrete/ECDSASignatureTest.java

@@ -3,7 +3,6 @@ package meerkat.crypto.concrete;
 import com.google.protobuf.ByteString;
 import com.google.protobuf.Message;
 import meerkat.protobuf.Crypto;
-import meerkat.crypto.concrete.ECDSASignature;
 import org.junit.Before;
 import org.junit.Test;
 

polling-station/build.gradle

@@ -41,6 +41,14 @@ version += "${isSnapshot ? '-SNAPSHOT' : ''}"
 dependencies {
     // Meerkat common
     compile project(':meerkat-common')
+    compile project(':restful-api-common')
+
+    // Jersey for RESTful API
+    compile 'org.glassfish.jersey.containers:jersey-container-servlet:2.5.+'
+
+    // Servlets
+    compile 'org.eclipse.jetty:jetty-server:9.3.+'
+    compile 'org.eclipse.jetty:jetty-servlet:9.3.+'
 
     // Logging
     compile 'org.slf4j:slf4j-api:1.7.7'

polling-station/src/main/java/meerkat/pollingstation/PollingStationScannerWebApp.java

@@ -0,0 +1,88 @@
+package meerkat.pollingstation;
+
+/**
+ * Created by Arbel on 5/31/2016.
+ */
+
+import com.google.common.util.concurrent.FutureCallback;
+import com.google.protobuf.BoolValue;
+import meerkat.protobuf.PollingStation;
+
+import javax.annotation.PostConstruct;
+import javax.servlet.ServletContext;
+import javax.ws.rs.Consumes;
+import javax.ws.rs.POST;
+import javax.ws.rs.Path;
+import javax.ws.rs.Produces;
+import javax.ws.rs.core.Context;
+import java.io.IOException;
+
+import static meerkat.pollingstation.PollingStationConstants.POLLING_STATION_WEB_SCANNER_ERROR_PATH;
+import static meerkat.pollingstation.PollingStationConstants.POLLING_STATION_WEB_SCANNER_SCAN_PATH;
+import static meerkat.rest.Constants.MEDIATYPE_PROTOBUF;
+
+/**
+ * Implements a Web-App interface for {@link meerkat.pollingstation.PollingStationScanner.Producer}
+ * This class depends on {@link meerkat.pollingstation.PollingStationWebScanner} and works in conjunction with it
+ */
+@Path("/")
+public class PollingStationScannerWebApp implements PollingStationScanner.Producer {
+
+    @Context
+    ServletContext servletContext;
+
+    Iterable<FutureCallback<PollingStation.ScannedData>> callbacks;
+
+    /**
+     * This method is called by the Jetty engine when instantiating the servlet
+     */
+    @PostConstruct
+    public void init() throws Exception{
+        callbacks = (Iterable<FutureCallback<PollingStation.ScannedData>>) servletContext.getAttribute(PollingStationWebScanner.CALLBACKS_ATTRIBUTE_NAME);
+    }
+
+    @POST
+    @Path(POLLING_STATION_WEB_SCANNER_SCAN_PATH)
+    @Consumes(MEDIATYPE_PROTOBUF)
+    @Produces(MEDIATYPE_PROTOBUF)
+    @Override
+    public BoolValue newScan(PollingStation.ScannedData scannedData) {
+
+        boolean handled = false;
+
+        for (FutureCallback<PollingStation.ScannedData> callback : callbacks){
+
+            callback.onSuccess(scannedData);
+            handled = true;
+
+        }
+
+        return BoolValue.newBuilder()
+                .setValue(handled)
+                .build();
+
+    }
+
+    @POST
+    @Path(POLLING_STATION_WEB_SCANNER_ERROR_PATH)
+    @Consumes(MEDIATYPE_PROTOBUF)
+    @Produces(MEDIATYPE_PROTOBUF)
+    @Override
+    public BoolValue reportScanError(PollingStation.ErrorMsg errorMsg) {
+
+        boolean handled = false;
+
+        for (FutureCallback<PollingStation.ScannedData> callback : callbacks){
+
+            callback.onFailure(new IOException(errorMsg.getMsg()));
+            handled = true;
+
+        }
+
+        return BoolValue.newBuilder()
+                .setValue(handled)
+                .build();
+
+    }
+
+}

polling-station/src/main/java/meerkat/pollingstation/PollingStationWebScanner.java

@@ -0,0 +1,60 @@
+package meerkat.pollingstation;
+
+import java.util.List;
+import java.util.LinkedList;
+
+import com.google.common.util.concurrent.FutureCallback;
+import org.eclipse.jetty.server.Server;
+import org.eclipse.jetty.servlet.*;
+
+import org.glassfish.jersey.servlet.ServletContainer;
+import org.glassfish.jersey.server.ResourceConfig;
+
+import meerkat.protobuf.PollingStation.ScannedData;
+import meerkat.rest.*;
+
+/**
+ * Created by Arbel on 05/05/2016.
+ */
+
+public class PollingStationWebScanner implements PollingStationScanner.Consumer{
+
+    public final static String CALLBACKS_ATTRIBUTE_NAME = "callbacks";
+
+    private final Server server;
+    private final List<FutureCallback<ScannedData>> callbacks;
+
+    public PollingStationWebScanner(int port, String subAddress) {
+
+        callbacks = new LinkedList<>();
+
+        server = new Server(port);
+
+        ServletContextHandler servletContextHandler = new ServletContextHandler(server, subAddress);
+        servletContextHandler.setAttribute(CALLBACKS_ATTRIBUTE_NAME, (Iterable<FutureCallback<ScannedData>>) callbacks);
+
+        ResourceConfig resourceConfig = new ResourceConfig(PollingStationScannerWebApp.class);
+        resourceConfig.register(ProtobufMessageBodyReader.class);
+        resourceConfig.register(ProtobufMessageBodyWriter.class);
+
+        ServletHolder servletHolder = new ServletHolder(new ServletContainer(resourceConfig));
+
+        servletContextHandler.addServlet(servletHolder, "/*");
+    }
+
+    @Override
+    public void start() throws Exception {
+        server.start();
+    }
+
+    @Override
+    public void stop() throws Exception {
+        server.stop();
+    }
+
+    @Override
+    public void subscribe(FutureCallback<ScannedData> scanCallback) {
+        callbacks.add(scanCallback);
+    }
+
+}

polling-station/src/test/java/meerkat/pollingstation/PollingStationWebScannerTest.java

@@ -0,0 +1,162 @@
+package meerkat.pollingstation;
+
+import com.google.common.util.concurrent.FutureCallback;
+import com.google.protobuf.ByteString;
+import meerkat.protobuf.PollingStation.*;
+import meerkat.rest.Constants;
+
+import meerkat.rest.*;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import javax.ws.rs.client.Client;
+import javax.ws.rs.client.ClientBuilder;
+import javax.ws.rs.client.Entity;
+import javax.ws.rs.client.WebTarget;
+import javax.ws.rs.core.Response;
+
+import java.util.concurrent.Semaphore;
+
+import static meerkat.pollingstation.PollingStationConstants.*;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+
+/**
+ * Created by Arbel on 25/05/2016.
+ */
+public class PollingStationWebScannerTest {
+
+    private PollingStationScanner.Consumer scanner;
+    private static final String ADDRESS = "http://localhost";
+    private static final String SUB_ADDRESS = "";
+    private static final int PORT = 8080;
+
+    private Semaphore semaphore;
+    private Throwable thrown;
+    private boolean dataIsAsExpected;
+
+    private class ScanHandler implements FutureCallback<ScannedData> {
+
+        private final ScannedData expectedData;
+
+        public ScanHandler(ScannedData expectedData) {
+            this.expectedData = expectedData;
+        }
+
+        @Override
+        public void onSuccess(ScannedData result) {
+            dataIsAsExpected = result.getData().equals(expectedData.getData());
+            semaphore.release();
+        }
+
+        @Override
+        public void onFailure(Throwable t) {
+            dataIsAsExpected = false;
+            thrown = t;
+            semaphore.release();
+        }
+    }
+
+    private class ErrorHandler implements FutureCallback<ScannedData> {
+
+        private final String expectedErrorMessage;
+
+        public ErrorHandler(String expectedErrorMessage) {
+            this.expectedErrorMessage = expectedErrorMessage;
+        }
+
+        @Override
+        public void onSuccess(ScannedData result) {
+            dataIsAsExpected = false;
+            semaphore.release();
+        }
+
+        @Override
+        public void onFailure(Throwable t) {
+            dataIsAsExpected = t.getMessage().equals(expectedErrorMessage);
+            semaphore.release();
+        }
+    }
+
+    @Before
+    public void init() {
+
+        System.err.println("Setting up Scanner WebApp!");
+
+        scanner = new PollingStationWebScanner(PORT, SUB_ADDRESS);
+
+        semaphore = new Semaphore(0);
+        thrown = null;
+
+        try {
+            scanner.start();
+        } catch (Exception e) {
+            assertThat("Could not start server: " + e.getMessage(), false);
+        }
+
+    }
+
+    @Test
+    public void testSuccessfulScan() throws InterruptedException {
+
+        Client client = ClientBuilder.newClient();
+        client.register(ProtobufMessageBodyReader.class);
+        client.register(ProtobufMessageBodyWriter.class);
+        WebTarget webTarget = client.target(ADDRESS + ":" + PORT)
+                .path(SUB_ADDRESS).path(POLLING_STATION_WEB_SCANNER_SCAN_PATH);
+
+        byte[] data = {(byte) 1, (byte) 2};
+
+        ScannedData scannedData = ScannedData.newBuilder()
+                .setData(ByteString.copyFrom(data))
+                .build();
+
+        scanner.subscribe(new ScanHandler(scannedData));
+
+        Response response = webTarget.request(Constants.MEDIATYPE_PROTOBUF).post(Entity.entity(scannedData, Constants.MEDIATYPE_PROTOBUF));
+        response.close();
+
+        semaphore.acquire();
+        assertThat("Scanner has thrown an error", thrown == null);
+        assertThat("Scanned data received was incorrect", dataIsAsExpected);
+
+    }
+
+    @Test
+    public void testErroneousScan() throws InterruptedException {
+
+        Client client = ClientBuilder.newClient();
+        client.register(ProtobufMessageBodyReader.class);
+        client.register(ProtobufMessageBodyWriter.class);
+        WebTarget webTarget = client.target(ADDRESS + ":" + PORT)
+                .path(SUB_ADDRESS).path(POLLING_STATION_WEB_SCANNER_ERROR_PATH);
+
+        ErrorMsg errorMsg = ErrorMsg.newBuilder()
+                .setMsg("!Error Message!")
+                .build();
+
+        scanner.subscribe(new ErrorHandler(errorMsg.getMsg()));
+
+        Response response = webTarget.request(Constants.MEDIATYPE_PROTOBUF).post(Entity.entity(errorMsg, Constants.MEDIATYPE_PROTOBUF));
+        response.close();
+
+        semaphore.acquire();
+        assertThat("Scanner error received was incorrect", dataIsAsExpected);
+
+    }
+
+    @After
+    public void close() {
+
+        System.err.println("Scanner WebApp shutting down...");
+
+        try {
+            scanner.stop();
+        } catch (Exception e) {
+            assertThat("Could not stop server: " + e.getMessage(), false);
+        }
+
+    }
+
+}

settings.gradle

@@ -4,4 +4,5 @@ include 'bulletin-board-server'
 include 'polling-station'
 include 'restful-api-common'
 include 'bulletin-board-client'
+include 'distributed-key-generation'