private async Task _SendHelloAsync(byte[] cookie)
{
var clientHello = new ClientHello
{
ClientVersion = this._Version,
Random = this._HandshakeInfo.ClientRandom,
Cookie = cookie
};
var cipherSuites = new ushort[this.SupportedCipherSuites.Count];
var index = 0;
foreach (var item in this.SupportedCipherSuites)
{
cipherSuites[index] = (ushort)item;
index++;
}
clientHello.CipherSuites = cipherSuites;
clientHello.CompressionMethods = new byte[1];
clientHello.CompressionMethods[0] = 0;
clientHello.Extensions = new Extensions
{
new Extension()
{
ExtensionType = TExtensionType.SessionTicketTLS
},
new Extension()
{
ExtensionType = TExtensionType.EncryptThenMAC
},
new Extension()
{
ExtensionType = TExtensionType.ExtendedMasterSecret
},
};
var ellipticCurvesExtension = new EllipticCurvesExtension();
for (var curve = 0; curve < (int)TEllipticCurve.secp521r1; curve++)
{
if (EllipticCurveFactory.SupportedCurve((TEllipticCurve)curve))
{
ellipticCurvesExtension.SupportedCurves.Add((TEllipticCurve)curve);
}
}
clientHello.Extensions.Add(new Extension(ellipticCurvesExtension));
var cllipticCurvePointFormatsExtension = new EllipticCurvePointFormatsExtension();
cllipticCurvePointFormatsExtension.SupportedPointFormats.Add(TEllipticCurvePointFormat.Uncompressed);
clientHello.Extensions.Add(new Extension(cllipticCurvePointFormatsExtension));
var signatureAlgorithmsExtension = new SignatureAlgorithmsExtension();
signatureAlgorithmsExtension.SupportedAlgorithms.Add(new SignatureHashAlgorithm()
{
Hash = THashAlgorithm.SHA1, Signature = TSignatureAlgorithm.RSA
});
clientHello.Extensions.Add(new Extension(signatureAlgorithmsExtension));
await this._SendHandshakeMessageAsync(clientHello, false, TimeSpan.FromSeconds(1)).ConfigureAwait(false);
}
private void SendHello(byte[] cookie)
{
ClientHello clientHello = new ClientHello
{
ClientVersion = SupportedVersion,
Random = _HandshakeInfo.ClientRandom,
Cookie = cookie
};
ushort[] cipherSuites = new ushort[_SupportedCipherSuites.Count];
int index = 0;
foreach (TCipherSuite item in _SupportedCipherSuites)
{
cipherSuites[index] = (ushort)item;
index++;
}
clientHello.CipherSuites = cipherSuites;
clientHello.CompressionMethods = new byte[1];
clientHello.CompressionMethods[0] = 0;
clientHello.Extensions = new Extensions();
clientHello.Extensions.Add(new Extension()
{
ExtensionType = TExtensionType.EncryptThenMAC
});
clientHello.Extensions.Add(new Extension()
{
ExtensionType = TExtensionType.ExtendedMasterSecret
});
EllipticCurvesExtension ellipticCurvesExtension = new EllipticCurvesExtension();
for (int curve = 0; curve < (int)TEllipticCurve.secp521r1; curve++)
{
if (EllipticCurveFactory.SupportedCurve((TEllipticCurve)curve))
{
ellipticCurvesExtension.SupportedCurves.Add((TEllipticCurve)curve);
}
}
clientHello.Extensions.Add(new Extension(ellipticCurvesExtension));
EllipticCurvePointFormatsExtension cllipticCurvePointFormatsExtension = new EllipticCurvePointFormatsExtension();
cllipticCurvePointFormatsExtension.SupportedPointFormats.Add(TEllipticCurvePointFormat.Uncompressed);
clientHello.Extensions.Add(new Extension(cllipticCurvePointFormatsExtension));
SignatureAlgorithmsExtension signatureAlgorithmsExtension = new SignatureAlgorithmsExtension();
signatureAlgorithmsExtension.SupportedAlgorithms.Add(new SignatureHashAlgorithm()
{
Hash = THashAlgorithm.SHA256, Signature = TSignatureAlgorithm.ECDSA
});
clientHello.Extensions.Add(new Extension(signatureAlgorithmsExtension));
_HandshakeInfo.InitaliseHandshakeHash(false);
SendHandshakeMessage(clientHello, false);
}
public static EllipticCurvesExtension Deserialise(Stream stream)
{
EllipticCurvesExtension result = new EllipticCurvesExtension();
ushort length = NetworkByteOrderConverter.ToUInt16(stream);
ushort supportedCurvesLength = (ushort)(length / 2);
if (supportedCurvesLength > 0)
{
for (uint index = 0; index < supportedCurvesLength; index++)
{
result.SupportedCurves.Add((TEllipticCurve)NetworkByteOrderConverter.ToUInt16(stream));
}
}
return result;
}
public static EllipticCurvesExtension Deserialise(Stream stream)
{
EllipticCurvesExtension result = new EllipticCurvesExtension();
ushort length = NetworkByteOrderConverter.ToUInt16(stream);
ushort supportedCurvesLength = (ushort)(length / 2);
if (supportedCurvesLength > 0)
{
for (uint index = 0; index < supportedCurvesLength; index++)
{
result.SupportedCurves.Add((TEllipticCurve)NetworkByteOrderConverter.ToUInt16(stream));
}
}
return(result);
}
public static Extension Deserialise(Stream stream, bool client)
{
if (stream == null)
{
throw new ArgumentNullException(nameof(stream));
}
Extension result = null;
if (stream.Position < stream.Length)
{
result = new Extension
{
ExtensionType = (TExtensionType)NetworkByteOrderConverter.ToUInt16(stream)
};
var length = NetworkByteOrderConverter.ToUInt16(stream);
if (length > 0)
{
if (result.ExtensionType == TExtensionType.EllipticCurves)
{
result.SpecificExtension = EllipticCurvesExtension.Deserialise(stream);
}
else if (result.ExtensionType == TExtensionType.ClientCertificateType)
{
result.SpecificExtension = ClientCertificateTypeExtension.Deserialise(stream, client);
}
else if (result.ExtensionType == TExtensionType.ServerCertificateType)
{
result.SpecificExtension = ServerCertificateTypeExtension.Deserialise(stream, client);
}
else if (result.ExtensionType == TExtensionType.SignatureAlgorithms)
{
result.SpecificExtension = SignatureAlgorithmsExtension.Deserialise(stream);
}
else
{
result.Data = new byte[length];
stream.Read(result.Data, 0, length);
}
}
}
return(result);
}
public static Extension Deserialise(Stream stream, bool client)
{
Extension result = null;
if (stream.Position < stream.Length)
{
result = new Extension();
result._ExtensionType = (TExtensionType)NetworkByteOrderConverter.ToUInt16(stream);
ushort length = NetworkByteOrderConverter.ToUInt16(stream);
if (length > 0)
{
if (result._ExtensionType == TExtensionType.EllipticCurves)
{
result._SpecifcExtension = EllipticCurvesExtension.Deserialise(stream);
}
else if (result._ExtensionType == TExtensionType.ClientCertificateType)
{
result._SpecifcExtension = ClientCertificateTypeExtension.Deserialise(stream, client);
}
else if (result._ExtensionType == TExtensionType.ServerCertificateType)
{
result._SpecifcExtension = ServerCertificateTypeExtension.Deserialise(stream, client);
}
else if (result._ExtensionType == TExtensionType.SignatureAlgorithms)
{
result._SpecifcExtension = SignatureAlgorithmsExtension.Deserialise(stream);
}
else
{
result._Data = new byte[length];
stream.Read(result._Data, 0, length);
}
}
}
return(result);
}
public void ProcessHandshake(DTLSRecord record)
{
#if DEBUG
Console.WriteLine($"> ProcessHandshake got {record}");
#endif
SocketAddress address = record.RemoteEndPoint.Serialize();
Session session = Sessions.GetSession(address);
byte[] data;
if ((session != null) && session.IsEncypted(record))
{
int count = 0;
while ((session.Cipher == null) && (count < (HandshakeTimeout / HANDSHAKE_DWELL_TIME)))
{
System.Threading.Thread.Sleep(HANDSHAKE_DWELL_TIME);
count++;
}
if (session.Cipher == null)
{
throw new Exception($"HandshakeTimeout: >{HandshakeTimeout}");
}
if (session.Cipher != null)
{
long sequenceNumber = ((long)record.Epoch << 48) + record.SequenceNumber;
data = session.Cipher.DecodeCiphertext(sequenceNumber, (byte)TRecordType.Handshake, record.Fragment, 0, record.Fragment.Length);
}
else
{
data = record.Fragment;
}
}
else
{
data = record.Fragment;
}
using (MemoryStream stream = new MemoryStream(data))
{
HandshakeRecord handshakeRecord = HandshakeRecord.Deserialise(stream);
if (handshakeRecord != null)
{
#if DEBUG
Console.WriteLine(handshakeRecord.MessageType.ToString());
#endif
switch (handshakeRecord.MessageType)
{
case THandshakeType.HelloRequest:
//HelloReq
break;
case THandshakeType.ClientHello:
ClientHello clientHello = ClientHello.Deserialise(stream);
if (clientHello != null)
{
byte[] cookie = clientHello.CalculateCookie(record.RemoteEndPoint, _HelloSecret);
if (clientHello.Cookie == null)
{
Version version = clientHello.ClientVersion;
if (ServerVersion < version)
{
version = ServerVersion;
}
if (session == null)
{
session = new Session
{
SessionID = Guid.NewGuid(),
RemoteEndPoint = record.RemoteEndPoint,
Version = version
};
Sessions.AddSession(address, session);
}
else
{
session.Reset();
session.Version = version;
}
session.ClientEpoch = record.Epoch;
session.ClientSequenceNumber = record.SequenceNumber;
//session.Handshake.UpdateHandshakeHash(data);
HelloVerifyRequest helloVerifyRequest = new HelloVerifyRequest
{
Cookie = cookie,
ServerVersion = ServerVersion
};
SendResponse(session, (IHandshakeMessage)helloVerifyRequest, 0);
}
else
{
if (session != null && session.Cipher != null && !session.IsEncypted(record))
{
session.Reset();
}
if (TLSUtils.ByteArrayCompare(clientHello.Cookie, cookie))
{
Version version = clientHello.ClientVersion;
if (ServerVersion < version)
{
version = ServerVersion;
}
if (clientHello.SessionID == null)
{
if (session == null)
{
session = new Session();
session.NextSequenceNumber();
session.SessionID = Guid.NewGuid();
session.RemoteEndPoint = record.RemoteEndPoint;
Sessions.AddSession(address, session);
}
}
else
{
Guid sessionID = Guid.Empty;
if (clientHello.SessionID.Length >= 16)
{
byte[] receivedSessionID = new byte[16];
Buffer.BlockCopy(clientHello.SessionID, 0, receivedSessionID, 0, 16);
sessionID = new Guid(receivedSessionID);
}
if (sessionID != Guid.Empty)
{
session = Sessions.GetSession(sessionID);
}
if (session == null)
{
//need to Find Session
session = new Session
{
SessionID = Guid.NewGuid()
};
session.NextSequenceNumber();
session.RemoteEndPoint = record.RemoteEndPoint;
Sessions.AddSession(address, session);
//session.Version = clientHello.ClientVersion;
}
}
session.Version = version;
session.Handshake.InitaliseHandshakeHash(version < DTLSRecord.Version1_2);
session.Handshake.UpdateHandshakeHash(data);
TCipherSuite cipherSuite = TCipherSuite.TLS_NULL_WITH_NULL_NULL;
foreach (TCipherSuite item in clientHello.CipherSuites)
{
if (_SupportedCipherSuites.ContainsKey(item) && CipherSuites.SupportedVersion(item, session.Version) && CipherSuites.SuiteUsable(item, PrivateKey, _PSKIdentities, _ValidatePSK != null))
{
cipherSuite = item;
break;
}
}
TKeyExchangeAlgorithm keyExchangeAlgorithm = CipherSuites.GetKeyExchangeAlgorithm(cipherSuite);
ServerHello serverHello = new ServerHello();
byte[] clientSessionID = new byte[32];
byte[] temp = session.SessionID.ToByteArray();
Buffer.BlockCopy(temp, 0, clientSessionID, 0, 16);
Buffer.BlockCopy(temp, 0, clientSessionID, 16, 16);
serverHello.SessionID = clientSessionID; // session.SessionID.ToByteArray();
serverHello.Random = new RandomData();
serverHello.Random.Generate();
serverHello.CipherSuite = (ushort)cipherSuite;
serverHello.ServerVersion = session.Version;
THashAlgorithm hash = THashAlgorithm.SHA256;
TEllipticCurve curve = TEllipticCurve.secp521r1;
if (clientHello.Extensions != null)
{
foreach (Extension extension in clientHello.Extensions)
{
if (extension.SpecifcExtension is ClientCertificateTypeExtension)
{
ClientCertificateTypeExtension clientCertificateType = extension.SpecifcExtension as ClientCertificateTypeExtension;
//TCertificateType certificateType = TCertificateType.Unknown;
//foreach (TCertificateType item in clientCertificateType.CertificateTypes)
//{
//}
//serverHello.AddExtension(new ClientCertificateTypeExtension(certificateType));
}
else if (extension.SpecifcExtension is EllipticCurvesExtension)
{
EllipticCurvesExtension ellipticCurves = extension.SpecifcExtension as EllipticCurvesExtension;
foreach (TEllipticCurve item in ellipticCurves.SupportedCurves)
{
if (EllipticCurveFactory.SupportedCurve(item))
{
curve = item;
break;
}
}
}
else if (extension.SpecifcExtension is ServerCertificateTypeExtension)
{
//serverHello.AddExtension();
}
else if (extension.SpecifcExtension is SignatureAlgorithmsExtension)
{
SignatureAlgorithmsExtension signatureAlgorithms = extension.SpecifcExtension as SignatureAlgorithmsExtension;
foreach (SignatureHashAlgorithm item in signatureAlgorithms.SupportedAlgorithms)
{
if (item.Signature == TSignatureAlgorithm.ECDSA)
{
hash = item.Hash;
break;
}
}
}
}
}
session.Handshake.CipherSuite = cipherSuite;
session.Handshake.ClientRandom = clientHello.Random;
session.Handshake.ServerRandom = serverHello.Random;
if (keyExchangeAlgorithm == TKeyExchangeAlgorithm.ECDHE_ECDSA)
{
EllipticCurvePointFormatsExtension pointFormatsExtension = new EllipticCurvePointFormatsExtension();
pointFormatsExtension.SupportedPointFormats.Add(TEllipticCurvePointFormat.Uncompressed);
serverHello.AddExtension(pointFormatsExtension);
}
session.Handshake.MessageSequence = 1;
SendResponse(session, serverHello, session.Handshake.MessageSequence);
session.Handshake.MessageSequence++;
if (keyExchangeAlgorithm == TKeyExchangeAlgorithm.ECDHE_ECDSA)
{
if (Certificate != null)
{
SendResponse(session, Certificate, session.Handshake.MessageSequence);
session.Handshake.MessageSequence++;
}
ECDHEKeyExchange keyExchange = new ECDHEKeyExchange
{
Curve = curve,
KeyExchangeAlgorithm = keyExchangeAlgorithm,
ClientRandom = clientHello.Random,
ServerRandom = serverHello.Random
};
keyExchange.GenerateEphemeralKey();
session.Handshake.KeyExchange = keyExchange;
if (session.Version == DTLSRecord.DefaultVersion)
{
hash = THashAlgorithm.SHA1;
}
ECDHEServerKeyExchange serverKeyExchange = new ECDHEServerKeyExchange(keyExchange, hash, TSignatureAlgorithm.ECDSA, PrivateKey);
SendResponse(session, serverKeyExchange, session.Handshake.MessageSequence);
session.Handshake.MessageSequence++;
if (_RequireClientCertificate)
{
CertificateRequest certificateRequest = new CertificateRequest();
certificateRequest.CertificateTypes.Add(TClientCertificateType.ECDSASign);
certificateRequest.SupportedAlgorithms.Add(new SignatureHashAlgorithm()
{
Hash = THashAlgorithm.SHA256, Signature = TSignatureAlgorithm.ECDSA
});
SendResponse(session, certificateRequest, session.Handshake.MessageSequence);
session.Handshake.MessageSequence++;
}
}
else if (keyExchangeAlgorithm == TKeyExchangeAlgorithm.ECDHE_PSK)
{
ECDHEKeyExchange keyExchange = new ECDHEKeyExchange
{
Curve = curve,
KeyExchangeAlgorithm = keyExchangeAlgorithm,
ClientRandom = clientHello.Random,
ServerRandom = serverHello.Random
};
keyExchange.GenerateEphemeralKey();
session.Handshake.KeyExchange = keyExchange;
ECDHEPSKServerKeyExchange serverKeyExchange = new ECDHEPSKServerKeyExchange(keyExchange);
SendResponse(session, serverKeyExchange, session.Handshake.MessageSequence);
session.Handshake.MessageSequence++;
}
else if (keyExchangeAlgorithm == TKeyExchangeAlgorithm.PSK)
{
PSKKeyExchange keyExchange = new PSKKeyExchange
{
KeyExchangeAlgorithm = keyExchangeAlgorithm,
ClientRandom = clientHello.Random,
ServerRandom = serverHello.Random
};
session.Handshake.KeyExchange = keyExchange;
//Need to be able to hint identity?? for PSK if not hinting don't really need key exchange message
//PSKServerKeyExchange serverKeyExchange = new PSKServerKeyExchange();
//SendResponse(session, serverKeyExchange, session.Handshake.MessageSequence);
//session.Handshake.MessageSequence++;
}
SendResponse(session, new ServerHelloDone(), session.Handshake.MessageSequence);
session.Handshake.MessageSequence++;
}
}
}
break;
case THandshakeType.ServerHello:
break;
case THandshakeType.HelloVerifyRequest:
break;
case THandshakeType.Certificate:
Certificate clientCertificate = Certificate.Deserialise(stream, TCertificateType.X509);
if (clientCertificate.CertChain.Count > 0)
{
session.CertificateInfo = Certificates.GetCertificateInfo(clientCertificate.CertChain[0], TCertificateFormat.CER);
}
session.Handshake.UpdateHandshakeHash(data);
break;
case THandshakeType.ServerKeyExchange:
break;
case THandshakeType.CertificateRequest:
break;
case THandshakeType.ServerHelloDone:
break;
case THandshakeType.CertificateVerify:
CertificateVerify certificateVerify = CertificateVerify.Deserialise(stream, session.Version);
session.Handshake.UpdateHandshakeHash(data);
break;
case THandshakeType.ClientKeyExchange:
if ((session == null) || (session.Handshake.KeyExchange == null))
{
}
else
{
session.Handshake.UpdateHandshakeHash(data);
byte[] preMasterSecret = null;
if (session.Handshake.KeyExchange.KeyExchangeAlgorithm == TKeyExchangeAlgorithm.ECDHE_ECDSA)
{
ECDHEClientKeyExchange clientKeyExchange = ECDHEClientKeyExchange.Deserialise(stream);
if (clientKeyExchange != null)
{
ECDHEKeyExchange ecKeyExchange = session.Handshake.KeyExchange as ECDHEKeyExchange;
preMasterSecret = ecKeyExchange.GetPreMasterSecret(clientKeyExchange.PublicKeyBytes);
}
}
else if (session.Handshake.KeyExchange.KeyExchangeAlgorithm == TKeyExchangeAlgorithm.ECDHE_PSK)
{
ECDHEPSKClientKeyExchange clientKeyExchange = ECDHEPSKClientKeyExchange.Deserialise(stream);
if (clientKeyExchange != null)
{
session.PSKIdentity = Encoding.UTF8.GetString(clientKeyExchange.PSKIdentity);
byte[] psk = _PSKIdentities.GetKey(clientKeyExchange.PSKIdentity);
if (psk == null)
{
psk = _ValidatePSK(clientKeyExchange.PSKIdentity);
if (psk != null)
{
_PSKIdentities.AddIdentity(clientKeyExchange.PSKIdentity, psk);
}
}
if (psk != null)
{
ECDHEKeyExchange ecKeyExchange = session.Handshake.KeyExchange as ECDHEKeyExchange;
byte[] otherSecret = ecKeyExchange.GetPreMasterSecret(clientKeyExchange.PublicKeyBytes);
preMasterSecret = TLSUtils.GetPSKPreMasterSecret(otherSecret, psk);
}
}
}
else if (session.Handshake.KeyExchange.KeyExchangeAlgorithm == TKeyExchangeAlgorithm.PSK)
{
PSKClientKeyExchange clientKeyExchange = PSKClientKeyExchange.Deserialise(stream);
if (clientKeyExchange != null)
{
session.PSKIdentity = Encoding.UTF8.GetString(clientKeyExchange.PSKIdentity);
byte[] psk = _PSKIdentities.GetKey(clientKeyExchange.PSKIdentity);
if (psk == null)
{
psk = _ValidatePSK(clientKeyExchange.PSKIdentity);
if (psk != null)
{
_PSKIdentities.AddIdentity(clientKeyExchange.PSKIdentity, psk);
}
}
if (psk != null)
{
ECDHEKeyExchange ecKeyExchange = session.Handshake.KeyExchange as ECDHEKeyExchange;
byte[] otherSecret = new byte[psk.Length];
preMasterSecret = TLSUtils.GetPSKPreMasterSecret(otherSecret, psk);
}
}
}
if (preMasterSecret != null)
{
//session.MasterSecret = TLSUtils.CalculateMasterSecret(preMasterSecret, session.KeyExchange);
//TLSUtils.AssignCipher(session);
session.Cipher = TLSUtils.AssignCipher(preMasterSecret, false, session.Version, session.Handshake);
}
else
{
Console.WriteLine($"preMasterSecret is null!");
}
}
break;
case THandshakeType.Finished:
Finished finished = Finished.Deserialise(stream);
if (session != null)
{
byte[] handshakeHash = session.Handshake.GetHash();
byte[] calculatedVerifyData = TLSUtils.GetVerifyData(session.Version, session.Handshake, false, true, handshakeHash);
#if DEBUG
Console.Write($"Handshake Hash: {TLSUtils.WriteToString(handshakeHash)}");
Console.Write($"Sent Verify: {TLSUtils.WriteToString(finished.VerifyData)}");
Console.Write($"Calc Verify: {TLSUtils.WriteToString(calculatedVerifyData)}");
#endif
if (TLSUtils.ByteArrayCompare(finished.VerifyData, calculatedVerifyData))
{
SendChangeCipherSpec(session);
session.Handshake.UpdateHandshakeHash(data);
handshakeHash = session.Handshake.GetHash();
Finished serverFinished = new Finished
{
VerifyData = TLSUtils.GetVerifyData(session.Version, session.Handshake, false, false, handshakeHash)
};
SendResponse(session, serverFinished, session.Handshake.MessageSequence);
session.Handshake.MessageSequence++;
}
else
{
throw new Exception();
}
}
break;
default:
break;
}
}
}
}
private void SendHello(byte[] cookie)
{
ClientHello clientHello = new ClientHello();
clientHello.ClientVersion = SupportedVersion;
clientHello.Random = _HandshakeInfo.ClientRandom;
clientHello.Cookie = cookie;
ushort[] cipherSuites = new ushort[_SupportedCipherSuites.Count];
int index = 0;
foreach (TCipherSuite item in _SupportedCipherSuites)
{
cipherSuites[index] = (ushort)item;
index++;
}
clientHello.CipherSuites = cipherSuites;
clientHello.CompressionMethods = new byte[1];
clientHello.CompressionMethods[0] = 0;
clientHello.Extensions = new Extensions();
clientHello.Extensions.Add(new Extension() { ExtensionType = TExtensionType.EncryptThenMAC});
clientHello.Extensions.Add(new Extension() { ExtensionType = TExtensionType.ExtendedMasterSecret });
EllipticCurvesExtension ellipticCurvesExtension = new EllipticCurvesExtension();
for (int curve = 0; curve < (int)TEllipticCurve.secp521r1; curve++)
{
if (EllipticCurveFactory.SupportedCurve((TEllipticCurve)curve))
{
ellipticCurvesExtension.SupportedCurves.Add((TEllipticCurve)curve);
}
}
clientHello.Extensions.Add(new Extension(ellipticCurvesExtension));
EllipticCurvePointFormatsExtension cllipticCurvePointFormatsExtension = new EllipticCurvePointFormatsExtension();
cllipticCurvePointFormatsExtension.SupportedPointFormats.Add(TEllipticCurvePointFormat.Uncompressed);
clientHello.Extensions.Add(new Extension(cllipticCurvePointFormatsExtension));
SignatureAlgorithmsExtension signatureAlgorithmsExtension = new SignatureAlgorithmsExtension();
signatureAlgorithmsExtension.SupportedAlgorithms.Add(new SignatureHashAlgorithm() { Hash= THashAlgorithm.SHA256, Signature = TSignatureAlgorithm.ECDSA });
clientHello.Extensions.Add(new Extension(signatureAlgorithmsExtension));
_HandshakeInfo.InitaliseHandshakeHash(false);
SendHandshakeMessage(clientHello, false);
}