public static byte[] Handle(PeerChatCTX ctx, byte[] data)
{
byte num1 = ctx.Buffer1;
byte num2 = ctx.Buffer2;
byte t;
int datapos = 0;
List <byte> buffer = new List <byte>();
long size = data.Length;
while (size-- > 0)
{
num1 = (byte)((num1 + 1) % 256);
num2 = (byte)((ctx.SBox[num1] + num2) % 256);
t = ctx.SBox[num1];
ctx.SBox[num1] = ctx.SBox[num2];
ctx.SBox[num2] = t;
t = (byte)((ctx.SBox[num2] + ctx.SBox[num1]) % 256);
byte temp = (byte)(data[datapos++] ^ ctx.SBox[t]);
buffer.Add(temp);
}
ctx.Buffer1 = num1;
ctx.Buffer2 = num2;
return(buffer.ToArray());
}
public ChatCrypt(string gameSecretKey)
{
ClientCtx = new PeerChatCTX();
ServerCtx = new PeerChatCTX();
Init(ClientCtx, ClientKey, gameSecretKey);
Init(ServerCtx, ServerKey, gameSecretKey);
}
/// <summary>
/// Prepare the key
/// </summary>
/// <param name="ctx"></param>
/// <param name="chall"></param>
/// <param name="gamekey"></param>
public static void Init(PeerChatCTX ctx, string challengeKey, string secretKey)
{
byte[] challengeBytes = UniSpyEncoding.GetBytes(challengeKey);
byte[] secretKeyBytes = UniSpyEncoding.GetBytes(secretKey);
ctx.Buffer1 = 0;
ctx.Buffer2 = 0;
int secretKeyIndex = 0;
for (int i = 0; i < challengeBytes.Length; i++, secretKeyIndex++)
{
if (secretKeyIndex >= secretKeyBytes.Length)
{
secretKeyIndex = 0;
}
challengeBytes[i] ^= secretKeyBytes[secretKeyIndex];
}
byte index1 = 255;
for (int i = 0; i < 256; i++, index1--)
{
ctx.SBox[i] = index1;
}
index1 = 0;
for (int i = 0, index2 = 0; i < ctx.SBox.Length; i++, index1++)
{
if (index1 >= challengeBytes.Length)
{
index1 = 0;
}
index2 = (byte)((challengeBytes[index1] + ctx.SBox[i] + index2) % 256);
byte t = ctx.SBox[i];
ctx.SBox[i] = ctx.SBox[index2];
ctx.SBox[index2] = t;
}
}