/// <summary>
/// Sends a message to Steam
/// </summary>
/// <param name="message">The message to send</param>
/// <returns>An awaitable task</returns>
protected internal async Task SendAsync(NetworkMessage message)
{
if (message == null)
{
throw new ArgumentNullException(nameof(message));
}
await NetLog.VerboseAsync($"Sending {(message.Protobuf ? "protobuf" : "struct")} message with type {message.MessageType}");
await SendAsync(message.WithClientInfo(_steamId, _sessionId).Serialize()).ConfigureAwait(false);
}
private async Task ProcessEncryptRequest(NetworkMessage message)
{
ChannelEncryptRequest encryptRequest = message.Deserialize <ChannelEncryptRequest>();
await NetLog.VerboseAsync($"Encrypting channel on protocol version {encryptRequest.ProtocolVersion} in universe {encryptRequest.Universe}").ConfigureAwait(false);
byte[] challange = encryptRequest.Challenge.All(b => b == 0) ? encryptRequest.Challenge : null; // check if all the values were made 0 by the marshal
byte[] publicKey = UniverseUtils.GetPublicKey(encryptRequest.Universe);
if (publicKey == null)
{
await NetLog.ErrorAsync($"Cannot find public key for universe {encryptRequest.Universe}").ConfigureAwait(false);
throw new InvalidOperationException($"Public key does not exist for universe {encryptRequest.Universe}");
}
byte[] tempSessionKey = CryptoUtils.GenerateBytes(32);
byte[] encryptedHandshake = null;
using (RsaCrypto rsa = new RsaCrypto(publicKey))
{
if (challange != null)
{
byte[] handshakeToEncrypt = new byte[tempSessionKey.Length + challange.Length];
Array.Copy(tempSessionKey, handshakeToEncrypt, tempSessionKey.Length);
Array.Copy(challange, 0, handshakeToEncrypt, tempSessionKey.Length, challange.Length);
encryptedHandshake = rsa.Encrypt(handshakeToEncrypt);
}
else
{
encryptedHandshake = rsa.Encrypt(tempSessionKey);
}
}
Encryption = challange != null ? (IEncryptor) new HmacEncryptor(tempSessionKey) : new SimpleEncryptor(tempSessionKey);
var encryptResponse = NetworkMessage.CreateMessage(MessageType.ChannelEncryptResponse, new ChannelEncryptResponse
{
KeySize = 128,
KeyHash = CryptoUtils.CrcHash(encryptedHandshake),
EncryptedHandshake = encryptedHandshake,
ProtocolVersion = 1,
});
await SendAsync(encryptResponse).ConfigureAwait(false);
}
