public static void DecryptPacket(ClientState state, byte[] packet)
{
using (var reader = new Reader(packet))
{
var ID = reader.ReadUInt16();
reader.Seek(3, SeekOrigin.Current);
var Version = reader.ReadUInt16();
byte[] cipherText = reader.ReadAllBytes, plainText;
var Name = Packet_Names.GetName(ID);
switch (ID)
{
case 20100:
case 20103:
{
plainText = cipherText;
break;
}
case 20104:
{
var nonce = GenericHash.Hash(
state.Nonce.Concat(state.ClientKey.PublicKey).Concat(state.ServerKey).ToArray(), null, 24);
plainText = PublicKeyBox.Open(cipherText, nonce, state.ClientKey.PrivateKey, state.ServerKey);
state.ServerState.Nonce = plainText.Take(24).ToArray();
state.ServerState.SharedKey = plainText.Skip(24).Take(32).ToArray();
plainText = plainText.Skip(24).Skip(32).ToArray();
break;
}
default:
{
state.ServerState.Nonce = Utilities.Increment(Utilities.Increment(state.ServerState.Nonce));
plainText = SecretBox.Open(new byte[16].Concat(cipherText).ToArray(), state.ServerState.Nonce,
state.ServerState.SharedKey);
break;
}
}
ServerCrypto.EncryptPacket(state.ServerState, ID, Version, plainText);
Console.WriteLine(
$"[{DateTime.Now.ToLongTimeString()}, SERVER, {ID}] {Resources.Definition.Decode(new Reader(plainText), ID)}");
Logger.Write(BitConverter.ToString(plainText).Replace("-", string.Empty), $"{ID}_{Name}",
LogType.PACKET);
}
}
