KeyExchangeECCurve25519
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Agreement;
using Org.BouncyCastle.Crypto.Generators;
using Org.BouncyCastle.Crypto.Parameters;
using Renci.SshNet.Abstractions;
using Renci.SshNet.Common;
using Renci.SshNet.Messages.Transport;
namespace Renci.SshNet.Security
{
internal sealed class KeyExchangeECCurve25519 : KeyExchangeEC
{
private X25519Agreement _keyAgreement;
public override string Name => "curve25519-sha256";
protected override int HashSize => 256;
public override void Start(Session session, KeyExchangeInitMessage message, bool sendClientInitMessage)
{
base.Start(session, message, sendClientInitMessage);
base.Session.RegisterMessage("SSH_MSG_KEX_ECDH_REPLY");
base.Session.KeyExchangeEcdhReplyMessageReceived += Session_KeyExchangeEcdhReplyMessageReceived;
X25519KeyPairGenerator val = new X25519KeyPairGenerator();
val.Init(new X25519KeyGenerationParameters(CryptoAbstraction.SecureRandom));
AsymmetricCipherKeyPair val2 = val.GenerateKeyPair();
_keyAgreement = new X25519Agreement();
_keyAgreement.Init(val2.get_Private());
_clientExchangeValue = val2.get_Public().GetEncoded();
SendMessage(new KeyExchangeEcdhInitMessage(_clientExchangeValue));
}
public override void Finish()
{
base.Finish();
base.Session.KeyExchangeEcdhReplyMessageReceived -= Session_KeyExchangeEcdhReplyMessageReceived;
}
protected override byte[] Hash(byte[] hashData)
{
return CryptoAbstraction.HashSHA256(hashData);
}
private void Session_KeyExchangeEcdhReplyMessageReceived(object sender, MessageEventArgs<KeyExchangeEcdhReplyMessage> e)
{
KeyExchangeEcdhReplyMessage message = e.Message;
base.Session.UnRegisterMessage("SSH_MSG_KEX_ECDH_REPLY");
HandleServerEcdhReply(message.KS, message.QS, message.Signature);
Finish();
}
private void HandleServerEcdhReply(byte[] hostKey, byte[] serverExchangeValue, byte[] signature)
{
_serverExchangeValue = serverExchangeValue;
_hostKey = hostKey;
_signature = signature;
X25519PublicKeyParameters val = new X25519PublicKeyParameters(serverExchangeValue);
byte[] array = new byte[_keyAgreement.get_AgreementSize()];
_keyAgreement.CalculateAgreement(val, array, 0);
base.SharedKey = Extensions.ToByteArray(array.ToBigInteger2(), false, true);
}
}
}