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.mux files are encrypted .ogg files and are typically used for custom track music. They use a simple, custom stream cipher based on a 16-byte key: a very long key is generated from the 16-byte key, and then every byte of the input file is xor'd with the corresponding byte in the long key.

File layout

byte magic[9] = "NadeoFile"
byte version = 1
int32 keySalt
byte data[]


First, the 16-byte decryption key is determined as follows:

key = md5(pack(keySalt) + "Hello,hack3r!")    // Hello, d3veloper :)

where pack() returns the bytes of its argument in little endian order, and the string is encoded as ASCII. Then, the data is decrypted as follows:

void Decrypt(byte[] data)
    for (int i = 0; i < data.Length; i++)
        data[i] ^= GetKeyStreamByte(i);

byte GetKeyStreamByte(int pos)
    return rol(key[pos % 16], (pos / 17) % 8);

byte rol(byte input, int amount)
    return (byte)((input << amount) | (input >> (8 - amount)));