55 lines
1.5 KiB
Java
55 lines
1.5 KiB
Java
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package FeldmanVerifiableSecretSharing;
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import ShamirSecretSharing.SecretSharing;
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import org.bouncycastle.util.Arrays;
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import org.factcenter.qilin.primitives.concrete.Zpstar;
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import java.math.BigInteger;
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import java.util.Random;
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/**
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* Created by Tzlil on 1/27/2016.
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*/
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public class VerifiableSecretSharing extends SecretSharing {
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private final BigInteger[] commitments;
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private final BigInteger g;
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public VerifiableSecretSharing(Zpstar zpstar, int t, int n, BigInteger s, Random random) {
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super(zpstar, t, n, s, random);
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this.g = BigInteger.ONE; //ToDO zpstar.getGenerator()
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this.commitments = generateCommitments();
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}
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private BigInteger[] generateCommitments() {
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BigInteger[] coefficients = polynomial.getCoefficients();
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BigInteger[] commitments = new BigInteger[coefficients.length];
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for (int i = 0 ; i < commitments.length;i++){
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commitments[i] = zpstar.multiply(g,coefficients[i]);
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}
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return commitments;
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}
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public BigInteger verify(int i) throws Exception {
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if(i < 1 || i > n){
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throw new Exception();
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}
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BigInteger v = BigInteger.ONE;
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int power = 1;
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for (int j = 0 ; j < commitments.length ; j ++){
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v.multiply(commitments[i].pow(power));
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power *=i;
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}
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return zpstar.add(BigInteger.ONE,v);
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}
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public BigInteger getG() {
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return g;
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}
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public BigInteger[] getCommitments() {
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return Arrays.clone(commitments);
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}
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}
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