AES - 如何将字符串（字节字符串）转换为字节（字节字符串）？

Question

我正在使用 python 和 AES 创建一个加密的聊天程序。我有一些从https://riptutorial.com/python/example/18926/symmetric-encryption-using-pycrypto收集的工作代码

import hashlib
import math
import os
import base64

from Crypto.Cipher import AES

IV_SIZE = 16    # 128 bit, fixed for the AES algorithm
KEY_SIZE = 32   # 256 bit meaning AES-256, can also be 128 or 192 bits
SALT_SIZE = 16  # This size is arbitrary

cleartext = b'Lorem ipsum'
password = b'highly secure encryption password'
salt = os.urandom(SALT_SIZE)
derived = hashlib.pbkdf2_hmac('sha256', password, salt, 100000,
                          dklen=IV_SIZE + KEY_SIZE)
iv = derived[0:IV_SIZE]
key = derived[IV_SIZE:]

encrypted = salt + AES.new(key, AES.MODE_CFB, iv).encrypt(cleartext)

print(encrypted)
############################################
# edit here: it is being pulled as a string instead of a byte string
encrypted = str(encrypted)
###########################################

# encrypted and enc2 should be the same, except for the salt.


encryptedString = base64.encodebytes(encrypted)

print(encryptedString) # <- this is what can be stored and fetched from mySQL

encrypted = base64.decodebytes(encryptedString) # <- get the bytes back

salt = encrypted[0:SALT_SIZE]
derived = hashlib.pbkdf2_hmac('sha256', password, salt, 100000,
                          dklen=IV_SIZE + KEY_SIZE)
iv = derived[0:IV_SIZE]
key = derived[IV_SIZE:]
cleartext = AES.new(key, AES.MODE_CFB, iv).decrypt(encrypted[SALT_SIZE:])

    print(cleartext)

当我运行上面的代码时，我得到一个 TypeError: expected bytes-like object, not str

我尝试了几种方法：

1. 字节（加密，'utf-8'） 这种方法的问题在于它最终再次加密了字符串。

2. 加密的.encode() 这和以前做的一样。

如何将字符串（字节字符串）转换为字节（字节字符串），而无需手动复制和粘贴字符串并在其前面放置 a b？

Answer 1

我运行了您链接到的示例，它运行良好，因此您的挑战似乎是将二进制数据存储到字符串中并再次恢复字节。任意字节都不是有效的 unicode 字符串，因此您需要将它们转码为有效的文本表示形式，例如 Base64。

这里有一些可能接近你想要的代码：

import hashlib
import math
import os
import base64

from Crypto.Cipher import AES

IV_SIZE = 16    # 128 bit, fixed for the AES algorithm
KEY_SIZE = 32   # 256 bit meaning AES-256, can also be 128 or 192 bits
SALT_SIZE = 16  # This size is arbitrary

cleartext = b'Lorem ipsum'
password = b'highly secure encryption password'
salt = os.urandom(SALT_SIZE)
derived = hashlib.pbkdf2_hmac('sha256', password, salt, 100000,
                              dklen=IV_SIZE + KEY_SIZE)
iv = derived[0:IV_SIZE]
key = derived[IV_SIZE:]

encrypted = salt + AES.new(key, AES.MODE_CFB, iv).encrypt(cleartext)

print(encrypted)

enc2=b'J\x82K\xf6\x10j\x06\xdbK\xd6\xf2\xc2Y\x98\xb9\x16\xb7\x0f\xfa\xb9\x19?\x9ak\xa1\xd5\xc4'

# encrypted and enc2 should be the same, except for the salt.

print(enc2)

encryptedString = base64.encodebytes(enc2)

print(encryptedString) # <- this is what can be stored and fetched from mySQL

encrypted = base64.decodebytes(encryptedString) # <- get the bytes back

salt = encrypted[0:SALT_SIZE]
derived = hashlib.pbkdf2_hmac('sha256', password, salt, 100000,
                              dklen=IV_SIZE + KEY_SIZE)
iv = derived[0:IV_SIZE]
key = derived[IV_SIZE:]
cleartext = AES.new(key, AES.MODE_CFB, iv).decrypt(encrypted[SALT_SIZE:])

print(cleartext)

运行这个，我得到了预期的输出：

b'\xc2\xc6\x81\x9f1\xdb@I\x155\xab6\xe5K\xb5\xfb\xe9\x93\x9c\xd6\xfc\xe1EN?\xdd\xaa'
b'J\x82K\xf6\x10j\x06\xdbK\xd6\xf2\xc2Y\x98\xb9\x16\xb7\x0f\xfa\xb9\x19?\x9ak\xa1\xd5\xc4'
b'SoJL9hBqBttL1vLCWZi5FrcP+rkZP5prodXE\n'
b'Lorem ipsum'

前两行是原始字节，第三行是Base64编码的字符串，用于解密Lorem imsum。