Python-сообщество

from Crypto.Cipher import AES
import base64
def _decrypt(msg, key = None):
    if key is None:
        key = 'mysecretpassword'
    obj = AES.new(key, AES.MODE_CBC, '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
    r = obj.decrypt(base64.b64decode(msg))
    padding = ord(r[-1])
    print padding
    return r[0:(-padding)]
def decrypt_request(msg):
    return _decrypt(msg)
request_crypted ='dasdasdsada'
request = decrypt_request(request_crypted)
print request

import random
import string
import base64
from Crypto import Random
from Crypto.Cipher import AES
import hashlib
def padding(s, bs=AES.block_size):
    if len(s) % bs == 0:
        return s + ''.join(random.SystemRandom().choice(string.ascii_lowercase + string.digits) for _ in range(bs - 1)) + chr(96 - bs)
    if len(s) % bs > 0 and len(s) > bs:
        res = s + ''.join(random.SystemRandom().choice(string.ascii_lowercase + string.digits) for _ in range(bs - len(s) % bs -1)) + chr(96 + len(s) % bs - bs)
    else:
        res = s + ''.join(random.SystemRandom().choice(string.ascii_lowercase + string.digits) for _ in range(bs - len(s) - 1)) + chr(96 + len(s) - bs)
    return res
def unpadding(s, bs=AES.block_size):
    return s[:ord(s[-1])-96] if len(s) % bs == 0 else ''
class AESCipher:
    def __init__(self, key):
        # Лучше использовать хэш от ключа, тогда длина ключа может быть произвольной,
        # а иначе нужно использовать ключи длиной 16, 24, 32 только...
        self.key = hashlib.md5(key).hexdigest()
    def encrypt(self, raw):
        raw = padding(raw)
        iv = Random.new().read(AES.block_size)
        cipher = AES.new(self.key, AES.MODE_CBC, iv)
        return base64.b64encode(iv + cipher.encrypt(raw))
    def decrypt(self, enc):
        enc = base64.b64decode(enc)
        iv = enc[:AES.block_size]
        cipher = AES.new(self.key, AES.MODE_CBC, iv)
        return unpadding(cipher.decrypt(enc[AES.block_size:]))
mycif = AESCipher(key='mypasskey')
msg = 'My secret message'
encrypted_msg1 = mycif.encrypt(msg)
print encrypted_msg1
encrypted_msg2 = mycif.encrypt(msg)
print encrypted_msg2 # Одинаковый текст каждый раз кодируется по-разному!
print mycif.decrypt(encrypted_msg1) # Хотя и разный, но одинаково расшифровывается!
print mycif.decrypt(encrypted_msg2)

>>> b'aaaaaaaaaaaaaaa\x01'
b'aaaaaaaaaaaaaaa\x01'
>>> len(_)
16
>>>

                                                                                                                          
>>> import random, string                                                                                                                                                                                  
>>>                                                                                                                                                                                                        
>>> def padding(s, bs=16):                                                                                                                                                                                 
...     if len(s) % bs == 0:                                                                                                                                                                               
...         return s + ''.join(random.SystemRandom().choice(string.ascii_lowercase + string.digits) for _ in range(bs - 1)) + chr(96 - bs)                                                                 
...     if len(s) % bs > 0 and len(s) > bs:                                                                                                                                                                
...         res = s + ''.join(random.SystemRandom().choice(string.ascii_lowercase + string.digits) for _ in range(bs - len(s) % bs -1)) + chr(96 + len(s) % bs - bs)                                       
...     else:                                                                                                                                                                                              
...         res = s + ''.join(random.SystemRandom().choice(string.ascii_lowercase + string.digits) for _ in range(bs - len(s) - 1)) + chr(96 + len(s) - bs)
...     return res
... 
>>> def unpadding(s, bs=16):
...     return s[:ord(s[-1])-96] if len(s) % bs == 0 else ''
...     
... 
>>> msg = b'aaaaaaaaaaaaaaa\x01'
>>> 
>>> print msg, padding(msg), unpadding(padding(msg))
aaaaaaaaaaaaaaa aaaaaaaaaaaaaaa1km4m7rnx50twwcP aaaaaaaaaaaaaaa
>>> 
>>> final = unpadding(padding(msg))
>>> 
>>> print final == msg
True
>>>