加密 &使用 PyCrypto AES 256 解密 [英] Encrypt & Decrypt using PyCrypto AES 256

问题描述

我正在尝试使用 PyCrypto 构建两个接受两个参数的函数:消息和密钥，然后加密/解密消息.

I'm trying to build two functions using PyCrypto that accept two parameters: the message and the key, and then encrypt/decrypt the message.

我在网上找到了几个链接来帮助我，但每个链接都有缺陷:

I found several links on the web to help me out, but each one of them has flaws:

codekoala 的这个使用 os.urandom，这是 PyCrypto 不鼓励的.

This one at codekoala uses os.urandom, which is discouraged by PyCrypto.

此外，我给函数的键不能保证具有预期的确切长度.我该怎么做才能做到这一点?

Moreover, the key I give to the function is not guaranteed to have the exact length expected. What can I do to make that happen ?

另外，有几种模式，推荐哪一种?我不知道该用什么:/

Also, there are several modes, which one is recommended? I don't know what to use :/

最后，IV 到底是什么?我可以为加密和解密提供不同的 IV，还是会返回不同的结果?

Finally, what exactly is the IV? Can I provide a different IV for encrypting and decrypting, or will this return in a different result?

编辑:删除了不安全的代码部分.

Edit: Removed the code part since it was not secure.

推荐答案

这是我的实现，对我有用，有一些修复，并增强了 32 字节和 iv 到 16 字节的密钥和秘密短语的对齐:

Here is my implementation and works for me with some fixes and enhances the alignment of the key and secret phrase with 32 bytes and iv to 16 bytes:

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 self._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:])]

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