/**
* Computes the server evidence message M2 using the previously verified values.
* To be called after successfully verifying the client evidence message M1.
* @return M2: the server side generated evidence message
* @throws CryptoException
*/
public virtual BigInteger CalculateServerEvidenceMessage()
{
// Verify pre-requirements
if (this.A == null || this.M1 == null || this.S == null)
{
throw new CryptoException("Impossible to compute M2: " +
"some data are missing from the previous operations (A,M1,S)");
}
// Compute the server evidence message 'M2'
this.M2 = Srp6Utilities.CalculateM2(digest, N, A, M1, S);
return(M2);
}
public virtual bool VerifyServerEvidenceMessage(BigInteger serverM2)
{
if (this.pubA == null || this.M1 == null || this.S == null)
{
throw new CryptoException("Impossible to compute and verify M2: some data are missing from the previous operations (A,M1,S)");
}
BigInteger bigInteger = Srp6Utilities.CalculateM2(this.digest, this.N, this.pubA, this.M1, this.S);
if (bigInteger.Equals(serverM2))
{
this.M2 = serverM2;
return(true);
}
return(false);
}
/** Authenticates the server evidence message M2 received and saves it only if correct.
* @param M2: the server side generated evidence message
* @return A boolean indicating if the server message M2 was the expected one.
* @throws CryptoException
*/
public virtual bool VerifyServerEvidenceMessage(BigInteger serverM2)
{
// Verify pre-requirements
if (this.pubA == null || this.M1 == null || this.S == null)
{
throw new CryptoException("Impossible to compute and verify M2: " +
"some data are missing from the previous operations (A,M1,S)");
}
// Compute the own server evidence message 'M2'
BigInteger computedM2 = Srp6Utilities.CalculateM2(digest, N, pubA, M1, S);
if (computedM2.Equals(serverM2))
{
this.M2 = serverM2;
return(true);
}
return(false);
}
