check keys of Yahoo! Axis

check_keys.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright : (c) SAEKI Yoshiyasu
# License   : MIT-style license
#             <http://www.opensource.org/licenses/mit-license.php>
# last updated: 2012/05/26

import binascii
import subprocess

crx = open("YAxis_Chrome_v1_0_20120520.crx", "rb")
# http://sxp.yimg.com/ei/ynano/YAxis_Chrome_v1_0_20120520.crx or
# https://github.com/nikcub/yahoo-spoof
magic_number = crx.read(4)  # http://code.google.com/chrome/extensions/crx.html
ver = crx.read(4)
pub_len = crx.read(4)
sig_len = crx.read(4)
real_pub_len = ord(pub_len.strip('\x00'))
pub_key = crx.read(real_pub_len)
pub_file = file("pub_key", "wb")
pub_file.write(pub_key)
pub_file.close()
pub_modulus = pub_key[29:(len(pub_key) - 5)]
# http://etherhack.co.uk/asymmetric/docs/rsa_key_breakdown.html
pub_modulus_hex = binascii.hexlify(pub_modulus).upper()
uzip = subprocess.Popen(
    "unzip -qc YAxis_Chrome_v1_0_20120520.crx nano_client.pem".split(" "),
    stdout=subprocess.PIPE)
ossl = subprocess.Popen("openssl rsa -noout -modulus".split(" "),
                        stdin=uzip.stdout, stdout=subprocess.PIPE)
uzip.stdout.close()
prv_modulus = ossl.communicate()[0].strip().split("=")[1]
print "Public key modulus:  ", pub_modulus_hex
print "Private key modulus: ", prv_modulus
if pub_modulus_hex == prv_modulus:
    print "match!"
else:
    print "not match"