Christmas CTF 2016 yumyum

yumyum.py

import ctypes
from gmpy2 import invert

libc = ctypes.CDLL('libc.so.6')
serial = "!qw/LF6V|RY'/]e/bqFVtB9;Z}]{-"
printable = range(32, 128)

for seed in range(80000):
	libc.srand(seed)
	r = [libc.rand() for i in range(len(serial))]
	try:
		s = ([(((((ord(x) + 566051) % 0xbf) * invert(17161, 0xbf)) - 415) % 0xbf * invert(y % 1031, 0xbf) % 0xbf) for x, y, in zip(serial, r)])
		if all(c in printable for c in s):
			print bytearray(s)
	except:
		continue