Here is the C# code for decrypting the files. Each data chunk is 1000 bytes length.
Code: Select all
private static uint[] GetKey(string key)
{
var temp = new byte[16];
byte[] hexKey = Encoding.ASCII.GetBytes(string.Concat(key, key.Substring(24, 8)));
for (int i = 0; i < 16; i++)
{
temp[i] = (byte)(hexKey[i] ^ hexKey[i + 16] ^ hexKey[i + 32]);
}
var result = new uint[temp.Length / sizeof(uint)];
Buffer.BlockCopy(temp, 0, result, 0, temp.Length);
return result;
}
private static void DecryptChunk(byte[] buffer, int size, IReadOnlyList<uint> key)
{
int chunkCount = size / 256;
for (int i = 0; i < chunkCount; i++)
{
var data = new uint[64];
Buffer.BlockCopy(buffer, i * 256, data, 0, 256);
DecryptBlock(data, 64, key);
Buffer.BlockCopy(data, 0, buffer, i * 256, 256);
}
// Process the last block
int lastBlockLength = (size - (chunkCount * 256)) / 4;
if (lastBlockLength > 0)
{
var data = new uint[lastBlockLength];
Buffer.BlockCopy(buffer, chunkCount * 256, data, 0, lastBlockLength * 4);
DecryptBlock(data, lastBlockLength, key);
Buffer.BlockCopy(data, 0, buffer, chunkCount * 256, lastBlockLength * 4);
}
// Process the last bytes
int lastBytesCount = size - (chunkCount * 256) - (lastBlockLength * 4);
if (lastBytesCount > 0)
{
for (int i = size - lastBytesCount; i < size; i++)
{
buffer[i] = (byte)(buffer[i] ^ (size - i) ^ 0xB7);
}
}
}
// It's a XXTEA algorithm
// See: https://en.wikipedia.org/wiki/XXTEA
private static void DecryptBlock(IList<uint> data, int blockLength, IReadOnlyList<uint> key)
{
uint counter = (uint)(((0x34 / blockLength) + 6) * -0x61c88647);
while (counter != 0)
{
uint keyBase = (counter >> 2) & 3;
uint next = data[0];
for (int i = blockLength - 1; i >= 0; i--)
{
uint previous = (i - 1) >= 0 ? data[i - 1] : data[blockLength - 1];
uint value1 = (next << 2) ^ (previous >> 5);
uint value2 = (next >> 3) ^ (previous << 4);
uint value3 = next ^ counter;
uint value4 = previous ^ key[(int)((i & 3) ^ keyBase)];
data[i] = data[i] - (value1 + value2 ^ value3 + value4);
next = data[i];
}
counter += 0x61c88647;
}
}
Anyway, none of the .xxx files has the game texts. I think they are encrypted inside the .exe file.
Do I need to upload the EXE file?