/// <summary>
/// Generates proofs that a token attribute value is not equal to any values in the target array.
/// </summary>
/// <param name="prover">Inequality proof parameters for the token.</param>
/// <param name="target">Target values array.</param>
/// <returns>An inequality proof.</returns>
public static InequalityProof[] GenerateUProveInequalityProofs(EQProofUProveProverData prover, byte[][] target)
{
// Create PedersenCommitments
int commitmentIndex = ClosedPedersenCommitment.GetCommitmentIndex(prover.PPPP.Committed, prover.index);
PedersenCommitment ped = new PedersenCommitment(prover.PPPP, prover.PP, prover.CPV, commitmentIndex);
// Create EqualityProof
CryptoParameters crypto = new CryptoParameters(prover.PPPP.IP);
InequalityProof[] proofs = new InequalityProof[target.Length];
for (int i = 0; i < target.Length; i++)
{
FieldZqElement targetValue = ProtocolHelper.ComputeXi(prover.PPPP.IP, prover.index - 1, target[i]);
proofs[i] = new InequalityProof(new ProverInequalityProofParameters(ped, targetValue, crypto));
}
return(proofs);
}
/// <summary>
/// Generates a proof that two attribute values are different, without revealing them.
/// </summary>
/// <param name="prover1">Equality proof parameters for the first token.</param>
/// <param name="prover2">Equality proof parameters for the second token.</param>
/// <returns>An inequality proof.</returns>
public static InequalityProof GenerateUProveInequalityProof(EQProofUProveProverData prover1, EQProofUProveProverData prover2)
{
if (!prover1.PPPP.IP.Gq.Equals(prover2.PPPP.IP.Gq))
{
throw new ArgumentException("both provers must share the same group");
}
// Create PedersenCommitments
int commitmentIndex1 = ClosedPedersenCommitment.GetCommitmentIndex(prover1.PPPP.Committed, prover1.index);
PedersenCommitment ped1 = new PedersenCommitment(prover1.PPPP, prover1.PP, prover1.CPV, commitmentIndex1);
int commitmentIndex2 = ClosedPedersenCommitment.GetCommitmentIndex(prover2.PPPP.Committed, prover2.index);
PedersenCommitment ped2 = new PedersenCommitment(prover2.PPPP, prover2.PP, prover2.CPV, commitmentIndex2);
// Create EqualityProof
CryptoParameters crypto = new CryptoParameters(prover1.PPPP.IP); // Can use prover2.IP
ProverInequalityProofParameters inequalityProver = new ProverInequalityProofParameters(ped1, ped2, crypto); // compares committed values in ped1 and ped2
return(new InequalityProof(inequalityProver));
}
/// <summary>
/// Generates a proof that a token attribute value is not equal to a target value.
/// </summary>
/// <param name="prover">Inequality proof parameters for the token.</param>
/// <param name="target">Target value.</param>
/// <returns>An inequality proof.</returns>
public static InequalityProof GenerateUProveInequalityProof(EQProofUProveProverData prover, byte[] target)
{
return(GenerateUProveInequalityProofs(prover, new byte[][] { target })[0]);
}