craxor.py

import hashlib
import math
import string
import argparse
import re
import functools


def main():
    parser = argparse.ArgumentParser(description='Brute force a string from a hex-digest.',
                                     epilog='Only "works" for strings with only lowercase letters and spaces.')
    parser.add_argument('-A', '--algorithm',
                        help='The hash algorithm used to generate the hex digest',
                        choices=hashlib.algorithms_available,
                        default='sha256')
    parser.add_argument('-H', '--hexdigest',
                        help='The hex encoded digest of the text we are brute-forcing.',
                        default='2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824')
    args = parser.parse_args()

    digest_size_map = {}
    constructor_map = {}
    for algo in hashlib.algorithms_available:
        h = hashlib.new(algo)
        digest_size_map[algo] = 2*h.digest_size
        try:
            constructor_map[algo] = getattr(hashlib, algo)
        except AttributeError:
            constructor_map[algo] = functools.partial(hashlib.new, algo)

    if len(args.hexdigest) != digest_size_map[args.algorithm]:
        print(f'Invalid hexdigest length for {args.algorithm}; required length is {digest_size_map[args.algorithm]}.')

    target_digest = args.hexdigest.lower()
    if re.match(r'^[0-9a-f]+$', target_digest) is None:
        print(f'Invalid hexdigest characters: must hex digits only.')

    symbols = (string.ascii_lowercase + ' ').encode()
    base = len(symbols)
    constructor = constructor_map[args.algorithm]

    i = 0
    text_i = symbols[:1]
    hash_i = constructor(text_i)
    digest_i = hash_i.hexdigest()

    while target_digest != digest_i:
        print('HAXING FAILED, TRYING AGAIN!~:', text_i.decode())

        i += 1
        text_i_length = int(math.log(i, base)) + 1
        text_i = bytearray(text_i_length)

        n = i
        for j in range(text_i_length - 1, -1, -1):
            n, m = divmod(n, base)
            text_i[j] = symbols[m]

        hash_i = constructor(text_i)
        digest_i = hash_i.hexdigest()

    print('HAXING SUCCESS!~:', text_i.decode())


if __name__ == '__main__':
    main()