public static String Decrypt(Byte[] mapKey, Byte[] encrypted)
{
Sha1 sha1 = new Sha1();
Byte[] xorKey = new Byte[encrypted.Length + 19];
UInt32 xorKeyLength = 0;
int counter = 0;
while (xorKeyLength < encrypted.Length)
{
Byte[] counterStringBytes = Encoding.ASCII.GetBytes(counter.ToString());
sha1.Add(counterStringBytes, 0, counterStringBytes.Length);
sha1.Add(mapKey, 0, mapKey.Length);
sha1.Add(sharedServerSecret, 0, sharedServerSecret.Length);
sha1.Add(counterStringBytes, 0, counterStringBytes.Length);
UInt32[] hash = sha1.Finish();
xorKey.BigEndianSetUInt32(xorKeyLength + 0, hash[0]);
xorKey.BigEndianSetUInt32(xorKeyLength + 4, hash[1]);
xorKey.BigEndianSetUInt32(xorKeyLength + 8, hash[2]);
xorKey.BigEndianSetUInt32(xorKeyLength + 12, hash[3]);
xorKey.BigEndianSetUInt32(xorKeyLength + 16, hash[4]);
xorKeyLength += 20;
sha1.Reset();
counter++;
}
Char[] decrypted = new Char[encrypted.Length];
for (int i = 0; i < decrypted.Length; i++)
{
decrypted[i] = (Char)(xorKey[i] ^ encrypted[i]);
}
return(new String(decrypted));
}