MMA CTF 1st 2015: Simple Hash - Bruteforce Script

#!/usr/bin/env pypy
# -*- coding: utf-8 -*-

import itertools
import string


TARGET = 0x1E1EAB437EEB0
ALPHABET = string.ascii_letters + string.digits

MOD = 0x38D7EA4C68025
COEFF = 0x241


def decode_full_hash_value(value):
    res = ''
    while value:
        code = value % COEFF
        res += chr(code)
        value /= COEFF
    return ''.join(reversed(res))


for i in itertools.count():  # 0, 1, 2, ...
    try:
        decoded = decode_full_hash_value(TARGET + MOD * i)
    except ValueError:
        # Can be raised if a code of some character >= 256,
        # then we'll just skip this string
        continue

    cur_score = sum(ch in ALPHABET for ch in decoded)
    wanted_score = len(decoded)
    if cur_score + 2 >= wanted_score:
        print '{} / {}'.format(cur_score, wanted_score),
        print ''.join('\\x' + hex(ord(ch))[2:].zfill(2) for ch in decoded)
        if cur_score == wanted_score:
            print 'Found:', decoded