hmacrypt/src/libs/seedable_aes.py
2024-02-10 22:40:45 +01:00

43 lines
1.2 KiB
Python

import base64
import hashlib
from Crypto import Random
from Crypto.Cipher import AES
class AESCipher(object):
def __init__(self, key):
self.bs = AES.block_size
self.key = hashlib.sha256(key.encode()).digest()
def encrypt(self, raw):
raw = self._pad(raw)
iv = Random.new().read(AES.block_size)
cipher = AES.new(self.key, AES.MODE_CBC, iv)
return base64.b64encode(iv + cipher.encrypt(raw.encode()))
def decrypt(self, enc):
enc = base64.b64decode(enc)
iv = enc[:AES.block_size]
cipher = AES.new(self.key, AES.MODE_CBC, iv)
return AESCipher._unpad(cipher.decrypt(enc[AES.block_size:])).decode('utf-8')
def _pad(self, s):
return s + (self.bs - len(s) % self.bs) * chr(self.bs - len(s) % self.bs)
@staticmethod
def _unpad(s):
return s[:-ord(s[len(s)-1:])]
# Implementable methods
# NOTE The cipher is initialized on the fly, so the seed is not stored
def self_encrypt_aes(seed, message):
cipher = AESCipher(seed)
encrypted = cipher.encrypt(message)
return encrypted
def self_decrypt_aes(seed, encrypted):
cipher = AESCipher(seed)
decrypted = cipher.decrypt(encrypted)
return decrypted