feistel_cipher.cpp

//-----
// encode:
//
    DWORD part1 = val[0];
    DWORD part2 = val[1];
    DWORD prev = 0;
    for (int i = 0; i < 16; i++) {
        DWORD res = part1 ^ encode_chunk(part2, t1[i], t2[i], t3[i]);
        part1 = part2;
        part2 = res;
    }
    val[0] = part2;
    val[1] = part1;


//-----
// decode:
//
    DWORD part1 = val[1];
    DWORD part2 = val[0];
    DWORD prev = 0;
    for (int i = 15; i >= 0; i--) {
        DWORD res = part2 ^ encode_chunk(part1, t1[i], t2[i], t3[i]);
        part2 = part1;
        part1 = res;
    }
    val[0] = part1;
    val[1] = part2;