/**
* Return the value M(2) that should be sent to the client
*
* @return M(2)
*/
public BigInteger getEvidenceValue_M2() {
if (fEvidenceValue_M1 == null) {
throw new IllegalStateException("computeCommonValue_S() has not been called yet.");
}
return SRPUtils.calcM2(fPublicKey_A, fEvidenceValue_M1, fCommonValue_S);
}
/**
* When the server sends M(2), call this method to validate the number.
*
* @param evidenceValueFromServer_M2 M(2) from the server.
* @throws SRPAuthenticationFailedException if M(2) is incorrect
*/
public void validateServerEvidenceValue_M2(BigInteger evidenceValueFromServer_M2)
throws SRPAuthenticationFailedException {
if (fEvidenceValue_M1 == null) {
throw new IllegalStateException("computeCommonValue_S() has not been called yet.");
}
BigInteger M2 = SRPUtils.calcM2(fPublicKey_A, fEvidenceValue_M1, fCommonValue_S);
if (!evidenceValueFromServer_M2.equals(M2)) {
throw new SRPAuthenticationFailedException("M(2) is incorrect");
}
}