Python dh Exemples

Exemple #1

import c33 # DH
import c10 # CBC mode
import c28 # SHA1
import binascii
import random

p = 0xffffffffffffffffc90fdaa22168c234c4c6628b80dc1cd129024e088a67cc74020bbea63b139b22514a08798e3404ddef9519b3cd3a431b302b0a6df25f14374fe1356d6d51c245e485b576625e7ec6f44c42e9a637ed6b0bff5cb6f406b7edee386bfb5a899fa5ae9f24117c4b1fe649286651ece45b3dc2007cb8a163bf0598da48361c55d39a69163fa8fd24cf5f83655d23dca3ad961c62f356208552bb9ed529077096966d670c354e4abc9804f1746c08ca237327ffffffffffffffff



print "\n\n========中间人攻击=======(g=1)"
print "中间人更改Alice和Bob的消息，使A=B=p="+str(p)
##### now Mallory comes into play
g = 1
Alice = c33.dh(random.randint(0,10000),p,g)
# A->M            Send "p", "g", "A"
# Mallory changes A to p # A^a mod p = p^a mod p = 0
# M->B            Send "p", "g", "p"
Bob = c33.dh(random.randint(0,10000),p,g)
Bob_secret = Bob.shsecret(Alice.A)
# B->M            Send "B"
# Mallory changes B to p # B^a mod p = p^a mod p = 0
# M->A            Send "p"
Alice_secret = Alice.shsecret(Bob.A)
print "shared key="+binascii.b2a_hex(c28.sha1(str(Alice_secret)).digest()[:16])
print "attack key="+binascii.b2a_hex(c28.sha1(str(1)).digest()[:16])
Alice_msg = "Alice hello OneA"
Alice_iv=''
for i in range(16):
    Alice_iv = Alice_iv+chr(random.randint(0,255))

Exemple #2

Fichier : c34.py Projet : mmmonk/matasano_crypto_challenge

#!/usr/bin/env python

import c33 # DH
import c10 # CBC mode
import c28 # SHA1

import random

p = 0xffffffffffffffffc90fdaa22168c234c4c6628b80dc1cd129024e088a67cc74020bbea63b139b22514a08798e3404ddef9519b3cd3a431b302b0a6df25f14374fe1356d6d51c245e485b576625e7ec6f44c42e9a637ed6b0bff5cb6f406b7edee386bfb5a899fa5ae9f24117c4b1fe649286651ece45b3dc2007cb8a163bf0598da48361c55d39a69163fa8fd24cf5f83655d23dca3ad961c62f356208552bb9ed529077096966d670c354e4abc9804f1746c08ca237327ffffffffffffffff
g = 2

print "############### normal exchange"
##### normal exchange

Alice = c33.dh(random.randint(0,10000),p,g)

# A->B            Send "p", "g", "A"
Bob = c33.dh(random.randint(0,10000),p,g)
Bob_secret = Bob.shsecret(Alice.A)

# B->A            Send "B"
Alice_secret = Alice.shsecret(Bob.A)

# on Alice
Alice_msg = "Alice says Hi"
Alice_iv = open("/dev/urandom").read(16)
Alice_enc = c10.cbcencrypt(Alice_msg,Alice_iv,c28.sha1(str(Alice_secret)).digest()[:16])
print "msg Alice send: "+Alice_msg

# A->B            Send AES-CBC(SHA1(s)[0:16], iv=random(16), msg) + iv

Exemple #3

Fichier : c35.py Projet : mmmonk/matasano_crypto_challenge

def exchange(p,g,Mallory=False,mg=0):

  # A->B            Send "p", "g"
  # B->A            Send ACK

  # with Mallory, M would send NACK to Alice suggesting new p and g values
  # and would send the same weak values to Bob, assuming there is no
  # check on weak values, the communications would be screwed

  if Mallory:
    g = mg

  Alice = c33.dh(random.randint(0,10000),p,g)

  # A->B            Send "p", "g", "A"
  Bob = c33.dh(random.randint(0,10000),p,g)
  Bob_secret = Bob.shsecret(Alice.A)

  # B->A            Send "B"
  Alice_secret = Alice.shsecret(Bob.A)

  # on Alice
  Alice_msg = "Alice says Hi"
  Alice_iv = open("/dev/urandom").read(16)
  Alice_enc = c10.cbcencrypt(Alice_msg,Alice_iv,c28.sha1(str(Alice_secret)).digest()[:16])
  print "msg Alice send: "+Alice_msg

  # A->B            Send AES-CBC(SHA1(s)[0:16], iv=random(16), msg) + iv
  if Mallory:
    print "Mallory intercepts:",
    if g == 1:
      print c10.cbcdecrypt(Alice_enc,Alice_iv,c28.sha1(str(1)).digest()[:16])
    elif g == p:
      print c10.cbcdecrypt(Alice_enc,Alice_iv,c28.sha1(str(0)).digest()[:16])
    elif g == p - 1:
      try:
        msg = c10.cbcdecrypt(Alice_enc,Alice_iv,c28.sha1(str(1)).digest()[:16])
      except:
        msg = c10.cbcdecrypt(Alice_enc,Alice_iv,c28.sha1(str(p-1)).digest()[:16])
      print msg
    else:
      print ""

  # on Bob
  print "msg Bob received: "+c10.cbcdecrypt(Alice_enc,Alice_iv,c28.sha1(str(Bob_secret)).digest()[:16])
  Bob_msg = "Bob says Hi"
  Bob_iv = open("/dev/urandom").read(16)
  Bob_enc = c10.cbcencrypt(Bob_msg,Bob_iv,c28.sha1(str(Bob_secret)).digest()[:16])
  print "msg Bob send: "+Bob_msg
  # B->A            Send AES-CBC(SHA1(s)[0:16], iv=random(16), A's msg) + iv

  if Mallory:
    print "Mallory intercepts:",
    if g == 1:
      print c10.cbcdecrypt(Bob_enc,Bob_iv,c28.sha1(str(1)).digest()[:16])
    elif g == p:
      print c10.cbcdecrypt(Bob_enc,Bob_iv,c28.sha1(str(0)).digest()[:16])
    elif g == p - 1:
      try:
        msg = c10.cbcdecrypt(Bob_enc,Bob_iv,c28.sha1(str(1)).digest()[:16])
      except:
        msg = c10.cbcdecrypt(Bob_enc,Bob_iv,c28.sha1(str(p-1)).digest()[:16])
      print msg
    else:
      print ""

  # on Alice
  print "msg Alice received: "+c10.cbcdecrypt(Bob_enc,Bob_iv,c28.sha1(str(Alice_secret)).digest()[:16])