p59.py

import itertools


def char_table():
    chars = []
    for c in range(128):
        good = False
        if 32 <= c < 127:
            good = True
        chars.append(good)
    return chars


def guess_keys(cipher):
    table = char_table()
    src = tuple(range(97, 123))
    step = 3
    for key in itertools.product(src, repeat=step):
        good = True
        for i, c in enumerate(cipher):
            k = key[i % len(key)]
            if not table[k ^ c]:
                #print('Failing after {} tries because {}'.format(i, k ^ c))
                good = False
                break
        if good:
            yield key


def apply_key(cipher, key):
    chars = []
    s = 0
    for i, c in enumerate(cipher):
        k = key[i % len(key)]
        chars.append(chr(k ^ c))
        s += k ^ c
    return s, ''.join(chars)


if __name__ == '__main__':
    cipher = []
    with open('p059_cipher.txt', mode='r') as f:
        for line in f.readlines():
            cipher.extend(int(i) for i in line.split(','))
    for pwd in guess_keys(cipher):
        print(pwd, apply_key(cipher, pwd))