/// <summary>
/// Encrypt data using MapleStory's AES method
/// </summary>
/// <param name="IV">IV to use for encryption</param>
/// <param name="data">data to encrypt</param>
/// <param name="length">length of data</param>
/// <param name="key">the AES key to use</param>
/// <returns>Crypted data</returns>
public static byte[] AesCrypt(byte[] IV, byte[] data, int length, byte[] key)
{
AesManaged crypto = new AesManaged();
crypto.KeySize = 256; //in bits
crypto.Key = key;
crypto.Mode = CipherMode.ECB; // Should be OFB, but this works too
MemoryStream memStream = new MemoryStream();
CryptoStream cryptoStream = new CryptoStream(memStream, crypto.CreateEncryptor(), CryptoStreamMode.Write);
int remaining = length;
int llength = 0x5B0;
int start = 0;
while (remaining > 0)
{
byte[] myIV = MapleCrypto.MultiplyBytes(IV, 4, 4);
if (remaining < llength)
{
llength = remaining;
}
for (int x = start; x < (start + llength); x++)
{
if ((x - start) % myIV.Length == 0)
{
cryptoStream.Write(myIV, 0, myIV.Length);
byte[] newIV = memStream.ToArray();
Array.Copy(newIV, myIV, myIV.Length);
memStream.Position = 0;
}
data[x] ^= myIV[(x - start) % myIV.Length];
}
start += llength;
remaining -= llength;
llength = 0x5B4;
}
try
{
cryptoStream.Dispose();
memStream.Dispose();
}
catch (Exception e)
{
Console.WriteLine("Error disposing AES streams" + e);
}
return(data);
}
/// <summary>
/// A loop to check for received packets
/// </summary>
private void ReceiveLoop()
{
if (this.TcpConnection.Connected)
{
while (this.TcpConnection.Available < 0x10)
{
Thread.Sleep(50);
}
byte[] buffer = new byte[0x10];
this.TcpConnection.GetStream().Read(buffer, 0, 0x10);
PacketReader Reader = new PacketReader(buffer);
Reader.ReadShort();
this.MapleVersion = Reader.ReadShort();
Reader.ReadMapleString();
this.SendCrypto = new MapleCrypto(Reader.ReadBytes(4), (short)this.MapleVersion);
this.ReceiveCrypto = new MapleCrypto(Reader.ReadBytes(4), (short)this.MapleVersion);
this.Ready = true;
while (this.TcpConnection.Connected)
{
if (this.TcpConnection.Available >= 4)
{
byte[] buffer2 = new byte[4];
this.TcpConnection.GetStream().Read(buffer2, 0, 4);
int packetLength = MapleCrypto.GetPacketLength(buffer2);
while (this.TcpConnection.Available < packetLength)
{
Thread.Sleep(20);
}
byte[] buffer3 = new byte[packetLength];
this.TcpConnection.GetStream().Read(buffer3, 0, packetLength);
this.ReceiveCrypto.Crypt(buffer3);
MapleCustomEncryption.Decrypt(buffer3);
Client.HandlePacket(buffer3);
}
Thread.Sleep(5);
}
this.Ready = false;
}
}
