def isValid(CipherText, Key, IV):
cipher = AES.AESCipher(Key, AES.MODE_CBC, IV)
plainText = cipher.decrypt(CipherText)
if unPad(plainText, 16) != "ERROR":
return True
return False
def isValid(CipherText, Key, IV):
cipher = AES.AESCipher(Key, AES.MODE_CBC, IV)
plainText = cipher.decrypt(CipherText)
if unPad(plainText, 16) != "ERROR":
return True
return False
iv_A = os.urandom(16)
iv_B = os.urandom(16)
msg_A = "Hello World"
cipher = AES.AESCipher(key_A, AES.MODE_CBC, iv_A)
send_A = cipher.encrypt("".join(pad(msg_A,16))) + iv_A
print "A -> B"
print "Send AES-CBC(SHA1(s)[0:16],iv=random(16),msg)"
received_B = send_A
iv_A_B = received_B[len(received_B) - 16:]
encrypted_A_B = received_B[:len(received_B) - 16]
cipher = AES.AESCipher(key_B, AES.MODE_CBC, iv_A_B)
msg_B = unPad(cipher.decrypt(encrypted_A_B),16)
cipher = AES.AESCipher(key_B, AES.MODE_CBC, iv_B)
send_B = cipher.encrypt("".join(pad(msg_B,16))) + iv_B
print "B -> A"
print "Send AES-CBC(SHA1(s)[0:16],iv=random(16),A's msg)"
received_A = send_B
iv_B_A = received_A[len(received_A) -16:]
encrypted_B_A = received_A[:len(received_A)-16]
cipher = AES.AESCipher(key_A, AES.MODE_CBC, iv_B_A)
msg = unPad(cipher.decrypt(encrypted_B_A),16)
print msg == msg_A == msg_B
