private static BigInteger Validate(BigInteger y, DHParameters dhParams)
{
if (y == null)
{
throw new ArgumentNullException("y");
}
// TLS check
if (y.CompareTo(BigInteger.Two) < 0 || y.CompareTo(dhParams.P.Subtract(BigInteger.Two)) > 0)
{
throw new ArgumentException("invalid DH public key", "y");
}
// we can't validate without Q.
if (dhParams.Q != null &&
!y.ModPow(dhParams.Q, dhParams.P).Equals(BigInteger.One))
{
throw new ArgumentException("y value does not appear to be in correct group", "y");
}
return(y);
}
protected DHKeyParameters(
bool isPrivate,
DHParameters parameters)
: this(isPrivate, parameters, PkcsObjectIdentifiers.DhKeyAgreement)
{
}
internal static int GetStrength(
DHParameters parameters)
{
return(parameters.L != 0 ? parameters.L : parameters.P.BitLength);
}