mkow

from struct import pack, unpack

# reversed from the challenge
def zz_helper(x, y, z):
    if y > z:
        return [1, z - x]
 
    a, b = zz_helper(y, x + y, z)
    if b >= x:
        return [2 * a + 1, b - x]

mkow

def split_by(data, cnt):
    return [data[i : i+cnt] for i in range(0, len(data), cnt)]

MAX_PATH = 150  # just some guessed estimate, should be fine

LEVELS = [
    'rbrr rgb rb  r brgrbrgb  grrgbbg grg bgrg  bbgrbg',
    'rrbrb rg g  bgrbgggr ggrgr gr rg brr  b  bggrbgbb',
    'rbr  bbggrgrggb   bggbb b  b bbrbbgg gbrrbgrbbb g',
]

mkow

// Solver for CRC Recursive Challenge from Dragon CTF 2021
// Author: Michał "Redford" Kowalczyk
//
// Could probably be much simpler, but this code was evolving for too long
// without a rewrite ¯\_(ツ)_/¯

#include <iostream>
#include <cstdio>
#include <cstddef>
#include <cstring>

mkow

// +0xABC0 (in .o)
bool ensure_calling_only_once_and_set_key_bit(
        unsigned __int64 addr_to_disasm_if_valid,
        unsigned int key_bit_ind,
        unsigned int a3,
        unsigned int ket_init_unique_id)
{
  char *addr; // rax
  char *retaddr; // [rsp+0h] [rbp+0h]