Last active
August 3, 2016 16:24
-
-
Save vqhuy/575b2f24a08891828cd5 to your computer and use it in GitHub Desktop.
re100 - SVATTT 2015
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
#!/usr/bin/env python | |
from z3 import * | |
def display_model(m): | |
block = {} | |
for x in m: | |
if 'b' in str(x): | |
block[ord(str(x)[-1:])] = int(str(m[x])) | |
password = ''.join(map(chr, block.values())) | |
print password | |
def get_models(F): | |
s = Solver() | |
s.add(F) | |
while True: | |
if s.check() == sat: | |
m = s.model() | |
display_model(m) | |
block = [] | |
for d in m: | |
if d.arity() > 0: | |
raise Z3Exception("uninterpreted functions are not suppported") | |
c = d() | |
if is_array(c) or c.sort().kind() == Z3_UNINTERPRETED_SORT: | |
raise Z3Exception("arrays and uninterpreted sorts are not supported") | |
block.append(c != m[d]) | |
s.add(Or(block)) | |
else: | |
break | |
def is_alphanum(x): | |
return Or(And(x >= 0x41, x <= 0x5a), And(x >= 0x61, x <= 0x7a), And(x >= 0x30, x <= 0x39)) | |
def calculate(password): | |
ret = BitVec('ret', 32) | |
i = BitVec('i', 8) | |
ret = 0 | |
for i in range(len(password)): | |
ret = If(password[i] & 0x01 > 0, ret + 1, ret) | |
ret = If(password[i] & 0x02 > 0, ret + 3, ret) | |
ret = If(password[i] & 0x04 > 0, ret + 128, ret) | |
ret = If(password[i] & 0x08 > 0, ret + 64, ret) | |
ret = If(password[i] & 0x10 > 0, ret + -3, ret) | |
ret = If(password[i] & 0x20 > 0, ret + -1, ret) | |
ret = If(password[i] & 0x40 > 0, ret * 64, ret) | |
return ret | |
if __name__ == '__main__': | |
for length in range(100): | |
print '[+] Trying with length %d ...' % length | |
F = [] | |
password = [BitVec("b%d" % i, 8) for i in range(length)] | |
F.extend([is_alphanum(password[i]) for i in range(length)]) | |
F.extend([ | |
calculate(password) == 4919 | |
]) | |
get_models(F) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment