meerkat-java/destributed-key-generation/src/test/java/JointFeldmanProtocol/DKGTest.java

package JointFeldmanProtocol;

import Communication.Network;
import ShamirSecretSharing.Polynomial;
import ShamirSecretSharing.SecretSharing;
import FeldmanVerifiableSecretSharing.VerifiableSecretSharing;
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.List;
import java.util.Random;

/**
 * Created by Tzlil on 2/9/2016.
 */
public class DKGTest {


    DistributedKeyGeneration[][] dkgsArrays;
    Thread[][] threadsArrays;
    int tests = 10;
    BigInteger p = BigInteger.valueOf(2903);
    BigInteger q = p.subtract(BigInteger.ONE).divide(BigInteger.valueOf(2));
    BigInteger[] secrets;
    @Before
    public void settings(){
        Zpstar zpstar = new Zpstar(p);
        Random random = new Random();
        BigInteger g;
        int t = 9;
        int n = 20;
        BigInteger ZERO = zpstar.zero();
        dkgsArrays = new DistributedKeyGeneration[tests][n];
        threadsArrays = new Thread[tests][n];
        secrets = new BigInteger[tests];
        for (int test = 0; test < tests; test++) {
            do {
                g = zpstar.sample(random);
            } while (!g.equals(ZERO) && !zpstar.multiply(g, q).equals(ZERO));// sample from QRZp*
            secrets[test] = BigInteger.ZERO;
            Network network = new Network(n);
            for (int i = 0; i < n; i++) {
                BigInteger secret = new BigInteger(q.bitLength(), random).mod(q);
                secrets[test] = secrets[test].add(secret).mod(q);
                dkgsArrays[test][i] = new DistributedKeyGeneration(t, n,secret, random, p, q, g, network);
                threadsArrays[test][i] = new Thread(dkgsArrays[test][i]);
            }
        }
    }

    public void oneTest(Thread[] threads, DistributedKeyGeneration[] dkgs,BigInteger secret) throws Exception {
        for (int i = 0; i < threads.length ; i++){
            threads[i].start();
        }
        for (int i = 0; i < threads.length ; i++){
            threads[i].join();
        }
        int t = dkgs[0].getT();
        int n = dkgs[0].getN();

        Zpstar zpstar = dkgs[0].getZpstar();
        BigInteger g = dkgs[0].getGenerator();

        // got the right public value
        assert(zpstar.multiply(g,secret).equals(dkgs[0].getY()));

        // assert all players agreed on the same public value
        for (int i = 0; i < dkgs.length - 1 ; i++){
            assert (dkgs[i].getY().equals(dkgs[i+1].getY()));
        }

        // assert valid verification values
        BigInteger expected,verification;
        for (int j = 1; j <= dkgs.length ; j++){
            expected = zpstar.multiply(g, dkgs[j - 1].getShare().y);
            verification = VerifiableSecretSharing.verify(j, dkgs[j - 1].getCommitments(),zpstar);
            assert (expected.equals(verification));
        }


        // restore the secret from t + 1 random shares
        Polynomial.Point[] shares = new Polynomial.Point[t + 1];
        for (int i = 0 ; i < shares.length; i++){
            shares[i] = dkgs[i].getShare();
        }
        //List<Integer> indexes = new ArrayList<Integer>(n);
        //for (int i = 1 ; i <= n; i ++){
        //    indexes.add(i);
        //}
        //Random random = new Random();
        //int index;
        //for (int i = 0 ; i < shares.length ; i++){
        //    index = indexes.remove(random.nextInt(indexes.size()));
        //    shares[i] = dkgs[index - 1].getShare();
        //}
        BigInteger calculatedSecret = SecretSharing.getSecrete(shares).mod(q);

        Polynomial polynomial = Polynomial.ZERO;
        for (int i = 0 ; i < dkgs.length ; i++){
            polynomial  = polynomial.add(dkgs[i].getPolynomial());
        }

        assert (calculatedSecret.equals(secret));

    }

    @Test
    public void secretSharingTest() throws Exception {
        for (int i = 0 ; i < dkgsArrays.length; i ++){
            oneTest(threadsArrays[i],dkgsArrays[i],secrets[i]);
        }
    }
}