KeyExchangeECCurve25519
using Renci.SshNet.Abstractions;
using Renci.SshNet.Common;
using Renci.SshNet.Messages.Transport;
using Renci.SshNet.Security.Chaos.NaCl;
using Renci.SshNet.Security.Chaos.NaCl.Internal.Ed25519Ref10;
using System.Security.Cryptography;
namespace Renci.SshNet.Security
{
internal sealed class KeyExchangeECCurve25519 : KeyExchangeEC
{
private byte[] _privateKey;
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;
byte[] array = new byte[MontgomeryCurve25519.PublicKeySizeInBytes];
array[0] = 9;
_privateKey = CryptoAbstraction.GenerateRandom(MontgomeryCurve25519.PrivateKeySizeInBytes);
_clientExchangeValue = new byte[MontgomeryCurve25519.PublicKeySizeInBytes];
MontgomeryOperations.scalarmult(_clientExchangeValue, 0, _privateKey, 0, array, 0);
SendMessage(new KeyExchangeEcdhInitMessage(_clientExchangeValue));
}
public override void Finish()
{
base.Finish();
base.Session.KeyExchangeEcdhReplyMessageReceived -= Session_KeyExchangeEcdhReplyMessageReceived;
}
protected override byte[] Hash(byte[] hashData)
{
using (SHA256 sHA = CryptoAbstraction.CreateSHA256())
return sHA.ComputeHash(hashData, 0, hashData.Length);
}
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;
byte[] array = new byte[MontgomeryCurve25519.PublicKeySizeInBytes];
MontgomeryOperations.scalarmult(array, 0, _privateKey, 0, serverExchangeValue, 0);
base.SharedKey = array.ToBigInteger2().ToByteArray().Reverse();
}
}
}