BcTlsDHDomain
BC light-weight support class for Diffie-Hellman key pair generation and key agreement over a
specified Diffie-Hellman configuration.
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Agreement;
using Org.BouncyCastle.Crypto.Generators;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Math;
using Org.BouncyCastle.Utilities;
using System;
namespace Org.BouncyCastle.Tls.Crypto.Impl.BC
{
public class BcTlsDHDomain : TlsDHDomain
{
protected readonly BcTlsCrypto m_crypto;
protected readonly TlsDHConfig m_config;
protected readonly DHParameters m_domainParameters;
private static byte[] EncodeValue(DHParameters dh, bool padded, BigInteger x)
{
if (!padded)
return BigIntegers.AsUnsignedByteArray(x);
return BigIntegers.AsUnsignedByteArray(GetValueLength(dh), x);
}
private static int GetValueLength(DHParameters dh)
{
return BigIntegers.GetUnsignedByteLength(dh.P);
}
public static BcTlsSecret CalculateDHAgreement(BcTlsCrypto crypto, DHPrivateKeyParameters privateKey, DHPublicKeyParameters publicKey, bool padded)
{
DHBasicAgreement dHBasicAgreement = new DHBasicAgreement();
dHBasicAgreement.Init(privateKey);
BigInteger x = dHBasicAgreement.CalculateAgreement(publicKey);
byte[] data = EncodeValue(privateKey.Parameters, padded, x);
return crypto.AdoptLocalSecret(data);
}
public static DHParameters GetDomainParameters(TlsDHConfig dhConfig)
{
DHGroup dHGroup = TlsDHUtilities.GetDHGroup(dhConfig);
if (dHGroup == null)
throw new ArgumentException("No DH configuration provided", "dhConfig");
DHGroup dHGroup2 = dHGroup;
return new DHParameters(dHGroup2.P, dHGroup2.G, dHGroup2.Q, dHGroup2.L);
}
public BcTlsDHDomain(BcTlsCrypto crypto, TlsDHConfig dhConfig)
{
m_crypto = crypto;
m_config = dhConfig;
m_domainParameters = GetDomainParameters(dhConfig);
}
public virtual BcTlsSecret CalculateDHAgreement(DHPrivateKeyParameters privateKey, DHPublicKeyParameters publicKey)
{
return CalculateDHAgreement(m_crypto, privateKey, publicKey, m_config.IsPadded);
}
public virtual TlsAgreement CreateDH()
{
return new BcTlsDH(this);
}
public virtual BigInteger DecodeParameter(byte[] encoding)
{
if (m_config.IsPadded && GetValueLength(m_domainParameters) != encoding.Length)
throw new TlsFatalAlert(47);
return new BigInteger(1, encoding);
}
public virtual DHPublicKeyParameters DecodePublicKey(byte[] encoding)
{
try {
return new DHPublicKeyParameters(DecodeParameter(encoding), m_domainParameters);
} catch (Exception alertCause) {
throw new TlsFatalAlert(40, alertCause);
}
}
public virtual byte[] EncodeParameter(BigInteger x)
{
return EncodeValue(m_domainParameters, m_config.IsPadded, x);
}
public virtual byte[] EncodePublicKey(DHPublicKeyParameters publicKey)
{
return EncodeValue(m_domainParameters, true, publicKey.Y);
}
public virtual AsymmetricCipherKeyPair GenerateKeyPair()
{
DHKeyPairGenerator dHKeyPairGenerator = new DHKeyPairGenerator();
dHKeyPairGenerator.Init(new DHKeyGenerationParameters(m_crypto.SecureRandom, m_domainParameters));
return dHKeyPairGenerator.GenerateKeyPair();
}
}
}