/// <summary>
/// Generates the second issuance message.
/// </summary>
/// <param name="message">The first issuance message.</param>
/// <returns>The second issuance message.</returns>
public SecondIssuanceMessage GenerateSecondMessage(FirstIssuanceMessage message)
{
if (state != State.Initialized)
{
throw new InvalidOperationException("Prover not initialized properly");
}
Group Gq = ip.Gq;
this.sigmaZ = message.sigmaZ;
sigmaZPrime = new GroupElement[numberOfTokens];
sigmaAPrime = new GroupElement[numberOfTokens];
sigmaBPrime = new GroupElement[numberOfTokens];
sigmaCPrime = new FieldZqElement[numberOfTokens];
FieldZqElement[] sigmaC = new FieldZqElement[numberOfTokens];
for (int i = 0; i < numberOfTokens; i++)
{
FieldZqElement blindingExponent = alpha[i];
sigmaZPrime[i] = message.sigmaZ.Exponentiate(blindingExponent);
sigmaAPrime[i] = t1[i] * message.sigmaA[i];
sigmaBPrime[i] = sigmaZPrime[i].Exponentiate(beta1[i]) * t2[i] * message.sigmaB[i].Exponentiate(blindingExponent);
HashFunction hash = ip.HashFunction;
hash.Hash(h[i]);
hash.Hash(PI);
hash.Hash(sigmaZPrime[i]);
hash.Hash(sigmaAPrime[i]);
hash.Hash(sigmaBPrime[i]);
sigmaCPrime[i] = ip.Zq.GetElementFromDigest(hash.Digest);
sigmaC[i] = sigmaCPrime[i] + beta1[i];
}
state = State.Second;
return(new SecondIssuanceMessage(sigmaC));
}
/// <summary>
/// Generates the second issuance message.
/// </summary>
/// <param name="message">The first issuance message.</param>
/// <returns>The second issuance message.</returns>
public SecondIssuanceMessage GenerateSecondMessage(FirstIssuanceMessage message)
{
if (state != State.Initialized)
{
throw new InvalidOperationException("Prover not initialized properly");
}
Group Gq = ip.Gq;
this.sigmaZ = message.sigmaZ.Exponentiate(beta0Inverse); // remove the blind that was included in gamma (if no blind beta0Inverse = 1)
sigmaZPrime = new GroupElement[numberOfTokens];
sigmaAPrime = new GroupElement[numberOfTokens];
sigmaBPrime = new GroupElement[numberOfTokens];
sigmaCPrime = new FieldZqElement[numberOfTokens];
FieldZqElement[] sigmaC = new FieldZqElement[numberOfTokens];
for (int i = 0; i < numberOfTokens; i++)
{
FieldZqElement sigmaBExponent = alpha[i].Multiply(beta0Inverse); // will remove the collab-issuance blind, if present
sigmaZPrime[i] = this.sigmaZ.Exponentiate(alpha[i]);
sigmaAPrime[i] = t1[i] * message.sigmaA[i];
sigmaBPrime[i] = Gq.MultiExponentiate(new GroupElement[] { sigmaZPrime[i], h[i], message.sigmaB[i] }, new FieldZqElement[] { beta1[i], beta2[i], sigmaBExponent });
HashFunction hash = ip.HashFunction;
hash.Hash(h[i]);
hash.Hash(PI);
hash.Hash(sigmaZPrime[i]);
hash.Hash(sigmaAPrime[i]);
hash.Hash(sigmaBPrime[i]);
sigmaCPrime[i] = ip.Zq.GetElementFromDigest(hash.Digest);
sigmaC[i] = sigmaCPrime[i] + beta1[i];
}
state = State.Second;
return(new SecondIssuanceMessage(sigmaC));
}
public static FirstIssuanceMessage convertFirstIssuanceMessageComposite(FirstIssuanceMessageComposite fic, IssuerParameters ip)
{
GroupElement[] geArray1 = new GroupElement[fic.SigmaA.Length];
for (int i = 0; i < fic.SigmaA.Length; i++)
{
geArray1[i] = ip.Gq.CreateGroupElement(fic.SigmaA[i]);
}
GroupElement[] geArray2 = new GroupElement[fic.SigmaB.Length];
for (int i = 0; i < fic.SigmaB.Length; i++)
{
geArray2[i] = ip.Gq.CreateGroupElement(fic.SigmaB[i]);
}
FirstIssuanceMessage fi = new FirstIssuanceMessage(ip.Gq.CreateGroupElement(fic.SigmaZ), geArray1, geArray2);
return fi;
}
public static FirstIssuanceMessageComposite convertFirstIssuanceMessage(FirstIssuanceMessage fi)
{
FirstIssuanceMessageComposite fic = new FirstIssuanceMessageComposite();
byte[][] byteArray1 = new byte[fi.sigmaA.Length][];
for (int i = 0; i < byteArray1.Length; i++)
{
byteArray1[i] = fi.sigmaA[i].GetEncoded();
}
byte[][] byteArray2 = new byte[fi.sigmaB.Length][];
for (int i = 0; i < byteArray2.Length; i++)
{
byteArray2[i] = fi.sigmaB[i].GetEncoded();
}
fic.SigmaA = byteArray1;
fic.SigmaB = byteArray2;
fic.SigmaZ = fi.sigmaZ.GetEncoded();
return fic;
}
/// <summary>
/// Generates the second issuance message.
/// </summary>
/// <param name="message">The first issuance message.</param>
/// <returns>The second issuance message.</returns>
public SecondIssuanceMessage GenerateSecondMessage(FirstIssuanceMessage message)
{
if (state != State.Initialized)
{
throw new InvalidOperationException("Prover not initialized properly");
}
Group Gq = ip.Gq;
this.sigmaZ = message.sigmaZ;
sigmaZPrime = new GroupElement[numberOfTokens];
sigmaAPrime = new GroupElement[numberOfTokens];
sigmaBPrime = new GroupElement[numberOfTokens];
sigmaCPrime = new FieldZqElement[numberOfTokens];
FieldZqElement[] sigmaC = new FieldZqElement[numberOfTokens];
for (int i = 0; i < numberOfTokens; i++)
{
FieldZqElement blindingExponent = alpha[i];
sigmaZPrime[i] = message.sigmaZ.Exponentiate(blindingExponent);
sigmaAPrime[i] = t1[i] * message.sigmaA[i];
sigmaBPrime[i] = sigmaZPrime[i].Exponentiate(beta1[i]) * t2[i] * message.sigmaB[i].Exponentiate(blindingExponent);
HashFunction hash = ip.HashFunction;
hash.Hash(h[i]);
hash.Hash(PI);
hash.Hash(sigmaZPrime[i]);
hash.Hash(sigmaAPrime[i]);
hash.Hash(sigmaBPrime[i]);
sigmaCPrime[i] = ip.Zq.GetElementFromDigest(hash.Digest);
sigmaC[i] = sigmaCPrime[i] + beta1[i];
}
state = State.Second;
return new SecondIssuanceMessage(sigmaC);
}