Created
December 28, 2016 13:39
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import base64 | |
import hashlib | |
from Crypto import Random | |
from Crypto.Cipher import AES | |
class AESCipher(object): | |
""" | |
A classical AES Cipher. Can use any size of data and any size of password thanks to padding. | |
Also ensure the coherence and the type of the data with a unicode to byte converter. | |
""" | |
def __init__(self, key): | |
self.bs = 32 | |
self.key = hashlib.sha256(AESCipher.str_to_bytes(key)).digest() | |
@staticmethod | |
def str_to_bytes(data): | |
u_type = type(b''.decode('utf8')) | |
if isinstance(data, u_type): | |
return data.encode('utf8') | |
return data | |
def _pad(self, s): | |
return s + (self.bs - len(s) % self.bs) * AESCipher.str_to_bytes(chr(self.bs - len(s) % self.bs)) | |
@staticmethod | |
def _unpad(s): | |
return s[:-ord(s[len(s)-1:])] | |
def encrypt(self, raw): | |
raw = self._pad(AESCipher.str_to_bytes(raw)) | |
iv = Random.new().read(AES.block_size) | |
cipher = AES.new(self.key, AES.MODE_CBC, iv) | |
return base64.b64encode(iv + cipher.encrypt(raw)).decode('utf-8') | |
def decrypt(self, enc): | |
enc = base64.b64decode(enc) | |
iv = enc[:AES.block_size] | |
cipher = AES.new(self.key, AES.MODE_CBC, iv) | |
return self._unpad(cipher.decrypt(enc[AES.block_size:])).decode('utf-8') | |
>>> cipher = AESCipher(key='mykey') | |
>>> encrypted = cipher.encrypt("Hello World") | |
>>> print(encrypted) | |
'/pgzr3fby2MD6hOvkzjAz6xRdkzzhOHG+iI0ZaPS7QWUGFppkgBybKY0RXzBaXAS' | |
>>> new_cipher = AESCipher(key='mykey') | |
>>> decrypted = new_cipher.decrypt('/pgzr3fby2MD6hOvkzjAz6xRdkzzhOHG+iI0ZaPS7QWUGFppkgBybKY0RXzBaXAS') | |
>>> print(decrypted) | |
'Hello World' |
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