/// <summary>
/// Check is the key is valid see RFC 2631, Section 2.1.5, http://www.ietf.org/rfc/rfc2631.txt
/// </summary>
public static bool IsValidPublicKey(Org.BouncyCastle.Math.BigInteger y, Org.BouncyCastle.Math.BigInteger p, Org.BouncyCastle.Math.BigInteger q)
{
Org.BouncyCastle.Math.BigInteger bn;
// y must lie in [2,p-1]
// check y < 2 then failed
bn = new Org.BouncyCastle.Math.BigInteger("2");
if (y.CompareTo(bn) < 0)
{
LibRTMPLogger.Log(LibRTMPLogLevel.Warning, "[CDR.LibRTMP.RTMPHelper.IsValidPublicKey] DH public key must be at least 2");
return false;
}
// y must lie in [2,p-1]
bn = new Org.BouncyCastle.Math.BigInteger(p.ToString());
bn = bn.Subtract(new Org.BouncyCastle.Math.BigInteger("1"));
if (y.CompareTo(bn) > 0)
{
LibRTMPLogger.Log(LibRTMPLogLevel.Warning, "[CDR.LibRTMP.RTMPHelper.IsValidPublicKey] DH public key must be at most p-2");
return false;
}
// Verify with Sophie-Germain prime
//
// This is a nice test to make sure the public key position is calculated
// correctly. This test will fail in about 50% of the cases if applied to
// random data.
bn = y.ModPow(q, p);
if (bn.CompareTo(new Org.BouncyCastle.Math.BigInteger("1")) != 0)
{
LibRTMPLogger.Log(LibRTMPLogLevel.Warning, "[CDR.LibRTMP.RTMPHelper.IsValidPublicKey] DH public key does not fulfill y^q mod p = 1");
return false;
}
return true;
}