#!/usr/bin/env python

# Written against python 3.3.1

# Matasano Problem 22

# "Crack" An MT19937 Seed

from prob21 import MT19937

from time import time

from random import randint

# Make sure your MT19937 accepts an integer seed value. Test it (verify

# that you're getting the same sequence of outputs given a seed).

def test_mt():

mt1 = MT19937(8675309);

mt2 = MT19937(8675309);

for i in range(10000):

if (mt1.extract_number() != mt2.extract_number()):

print("Fail MT test!");

# I do these exercises around 10pm. I'm not waiting for actual time to pass

initialTime = int(time());

delay1 = randint(40, 1000);

delay2 = randint(40, 1000);

# Write a routine that performs the following operation:

def randFromTime():

# * Seeds the RNG with the current Unix timestamp

mt = MT19937(initialTime + delay1);

#* Returns the first 32 bit output of the RNG.

return mt.extract_number();

# From the 32 bit RNG output, discover the seed.

def recoverSeed(output, timeNow):

# we're pretty sure that the seed is in the range (timeNow - 2005, timeNow)

# but we'll push the range check out to 10000 just for fun

for i in range(10000):

#guess seed

mt = MT19937(timeNow - i);

#check seed

if (output == mt.extract_number()):

print("Seed: ", timeNow - i);

return i;

print("Failed to recover seed");

return -1;

if __name__ == "__main__":

test_mt();

# get random output

randOutput = randFromTime();

# try to recover the seed at the "current" time

recoverSeed(randOutput, int(time()) + delay1 + delay2);