forked from roughiz/Arkham-walktrough
/
viewstate.py
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/
viewstate.py
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import pyDes
import base64
import argparse
from Crypto.Hash import SHA, HMAC
text= "wHo0wmLu5ceItIi+I7XkEi1GAb4h12WZ894pA+Z4OH7bco2jXEy1RQxTqLYuokmO70KtDtngjDm0mNzA9qHjYerxo0jW7zu1mdKBXtxnT1RmnWUWTJyCuNcJuxE="
key = 'SnNGOTg3Ni0='
mac_length = 20
def viewstate_decrypt(mykey,mytext):
print "###################Viewstate Decryption###########################\n"
d = pyDes.des(mykey,pyDes.ECB,padmode=pyDes.PAD_PKCS5)
output = base64.decodestring(mytext)
data = output[:len(output)-mac_length]
mac = output[len(output)-mac_length:]
decrypted_data = d.decrypt(data)
new_mac = HMAC.new(mykey, data, SHA)
verified_mac = new_mac.digest()
print "\ndata decrypted: %r" % decrypted_data
print "\nmac found: %r" % mac
print "\nmac calculate: %r" % verified_mac
if mac == verified_mac :
print '\nMessage authentication code (mac) is the same '
return 0
return 1
def viewstate_encrypt(mykey,payload):
d = pyDes.des(mykey,pyDes.ECB,padmode=pyDes.PAD_PKCS5)
output = d.encrypt(payload)
mac = HMAC.new(mykey, output, SHA).digest()
output+=mac
final = base64.b64encode(output)
return final
parser = argparse.ArgumentParser(description='Viewstate encryption, decryption ')
parser.add_argument('-a','--action', help='Define the action to do (encrypt or decrypt)', default='decrypt')
args = vars(parser.parse_args())
# Decode the key from base64
key= base64.decodestring(key)
if args['action'] == 'decrypt':
## decrypt a viewstate data
viewstate_decrypt(key,text)
## encrypt a payload
if args['action'] == 'encrypt':
payload = open('payload','rb').read()
final = viewstate_encrypt(key,payload)
print final