From c3e651e34bcfbf7045b0f72ca69a1d30cd1e121c Mon Sep 17 00:00:00 2001
From: Tal Moran <talm@idc.ac.il>
Date: Mon, 16 Nov 2015 14:44:06 +0200
Subject: [PATCH] Added encrypted message protobuf, and updated encryption API.

---
 .../src/main/java/meerkat/crypto/Encryption.java | 10 +++++++++-
 .../main/java/meerkat/crypto/mixnet/Mixer.java   |  3 +--
 .../java/meerkat/voting/EncryptedBallot.java     | 16 ----------------
 .../src/main/proto/meerkat/crypto.proto          |  8 +++++++-
 .../src/main/proto/meerkat/voting.proto          |  6 ++++++
 5 files changed, 23 insertions(+), 20 deletions(-)
 delete mode 100644 meerkat-common/src/main/java/meerkat/voting/EncryptedBallot.java

diff --git a/meerkat-common/src/main/java/meerkat/crypto/Encryption.java b/meerkat-common/src/main/java/meerkat/crypto/Encryption.java
index a1a023b..0ec6c11 100644
--- a/meerkat-common/src/main/java/meerkat/crypto/Encryption.java
+++ b/meerkat-common/src/main/java/meerkat/crypto/Encryption.java
@@ -7,6 +7,14 @@ import static meerkat.protobuf.Crypto.*;
  * Created by talm on 11/2/15.
  */
 public interface Encryption {
-    Message encrypt(Message plaintext, EncryptionRandomness rnd);
+    /**
+     * Encrypt the serialized form of a message plaintext.
+     * @param plaintext
+     * @param rnd
+     * @return
+     */
+    RerandomizableEncryptedMessage encrypt(Message plaintext, EncryptionRandomness rnd); // TODO: type of exception; throws
+
+    RerandomizableEncryptedMessage rerandomize(RerandomizableEncryptedMessage msg, EncryptionRandomness rnd);
 
 }
diff --git a/meerkat-common/src/main/java/meerkat/crypto/mixnet/Mixer.java b/meerkat-common/src/main/java/meerkat/crypto/mixnet/Mixer.java
index 44b113b..52e8844 100644
--- a/meerkat-common/src/main/java/meerkat/crypto/mixnet/Mixer.java
+++ b/meerkat-common/src/main/java/meerkat/crypto/mixnet/Mixer.java
@@ -1,8 +1,7 @@
 package meerkat.crypto.mixnet;
 
-import meerkat.voting.EncryptedBallot;
-
 import java.util.List;
+import static meerkat.protobuf.Voting.*;
 
 /**
  * Created by talm on 25/10/15.
diff --git a/meerkat-common/src/main/java/meerkat/voting/EncryptedBallot.java b/meerkat-common/src/main/java/meerkat/voting/EncryptedBallot.java
deleted file mode 100644
index 8f86128..0000000
--- a/meerkat-common/src/main/java/meerkat/voting/EncryptedBallot.java
+++ /dev/null
@@ -1,16 +0,0 @@
-package meerkat.voting;
-
-import com.google.protobuf.Message;
-
-/**
- * Created by talm on 25/10/15.
- */
-public interface EncryptedBallot {
-    /**
-     * Return the public portion of the ballot (this can be published to the bulletin board without violating privacy).
-     * @return
-     */
-    Message getPublicPortion();
-
-
-}
diff --git a/meerkat-common/src/main/proto/meerkat/crypto.proto b/meerkat-common/src/main/proto/meerkat/crypto.proto
index feafc1c..ecd9478 100644
--- a/meerkat-common/src/main/proto/meerkat/crypto.proto
+++ b/meerkat-common/src/main/proto/meerkat/crypto.proto
@@ -41,4 +41,10 @@ message EncryptionRandomness {
 // A proof that randomness is correctly generated
 message RandomnessGenerationProof {
     bytes data = 1;
-}
\ No newline at end of file
+}
+
+// An encrypted message (rerandomizable)
+message RerandomizableEncryptedMessage {
+    bytes data = 1;
+}
+
diff --git a/meerkat-common/src/main/proto/meerkat/voting.proto b/meerkat-common/src/main/proto/meerkat/voting.proto
index 5d2586a..f7195e2 100644
--- a/meerkat-common/src/main/proto/meerkat/voting.proto
+++ b/meerkat-common/src/main/proto/meerkat/voting.proto
@@ -49,6 +49,12 @@ message PlaintextBallot {
     repeated BallotAnswer answers = 2;
 }
 
+message EncryptedBallot {
+    uint64 serialNumber = 1; // Ballot serial number
+
+    RerandomizableEncryptedMessage data = 2;
+}
+
 message BallotSecrets {
     PlaintextBallot plaintext_ballot = 1;