/**
* Computes the client evidence message M1 using the previously received values.
* To be called after calculating the secret S.
* @return M1: the client side generated evidence message
* @throws CryptoException
*/
public virtual BigInteger CalculateClientEvidenceMessage()
{
// Verify pre-requirements
if (this.pubA == null || this.B == null || this.S == null)
{
throw new CryptoException("Impossible to compute M1: " +
"some data are missing from the previous operations (A,B,S)");
}
// compute the client evidence message 'M1'
this.M1 = Srp6Utilities.CalculateM1(digest, N, pubA, B, S);
return(M1);
}
/**
* Authenticates the received client evidence message M1 and saves it only if correct.
* To be called after calculating the secret S.
* @param M1: the client side generated evidence message
* @return A boolean indicating if the client message M1 was the expected one.
* @throws CryptoException
*/
public virtual bool VerifyClientEvidenceMessage(BigInteger clientM1)
{
// Verify pre-requirements
if (this.A == null || this.pubB == null || this.S == null)
{
throw new CryptoException("Impossible to compute and verify M1: " +
"some data are missing from the previous operations (A,B,S)");
}
// Compute the own client evidence message 'M1'
BigInteger computedM1 = Srp6Utilities.CalculateM1(digest, N, A, pubB, S);
if (computedM1.Equals(clientM1))
{
this.M1 = clientM1;
return(true);
}
return(false);
}