pycrypto aes加密抛出了两个错误

Question

我创建了一个小脚本来加密和解密文件，但是该文件为零字节，并且未创建解密的文件

代码：

from hashlib import md5
from Crypto import Random
from Crypto.Cipher import AES
import os
from Crypto import *
def encrypt(in_file, out_file, key, iv):
    bs = AES.block_size
    cipher = AES.new(key, AES.MODE_CBC, iv)
    finished = False
    while not finished:
        chunk = in_file.read(1024 * bs)
        if len(chunk) == 0 or len(chunk) % bs != 0:
            padding_length = bs - (len(chunk) % bs)
            chunk += bytes(padding_length) * chr(padding_length)
            finished = True
    out_file.write(cipher.encrypt(chunk))
def decrypt(in_file, out_file, key, iv):
    bs = AES.block_size
    cipher = AES.new(key, AES.MODE_CBC, iv)
    next_chunk = ''
    finished = False
    while not finished:
        chunk, next_chunk = next_chunk, cipher.decrypt(in_file.read(1024 * bs))
    if len(next_chunk) == 0:
        padding_length = ord(chunk[-1])
        if padding_length < 1 or padding_length > bs:
            raise ValueError("bad decrypt pad (%d)" % padding_length)
        if chunk[-padding_length:] != (padding_length * chr(padding_length)):
            raise ValueError("bad decrypt")
        chunk = chunk[:-padding_length]
        finished = True
    out_file.write(chunk)

in_file = open('C:/Users/saeed/Desktop/ImportantFolder/arrest.jpg', 'rb')
out_file = open('C:/Users/saeed/Desktop/ImportantFolder/arrest_enc.jpg', 'wb')
key = os.urandom(32)
iv = os.urandom(16)
encrypt(in_file, out_file, key, iv)
in_file.close()
out_file.close()
print('Encrypted!')
in_file = open('C:/Users/saeed/Desktop/ImportantFolder/arrest_enc.jpg', 'rb')
out_file = open('C:/Users/saeed/Desktop/ImportantFolder/arrest_dec.jpg', 'wb')
decrypt(in_file, out_file, key, iv)
in_file.close()
out_file.close()
print('Decrypted!')

被加密的文件，_是创建但为零字节，并且在代码停止时不能解密。它被卡在加密过程中，从不打印加密！错误：

Traceback (most recent call last):
  File "C:/Users/saeed/IdeaProjects/encryptor/encryption.py", line 41, in <module>
encrypt(in_file, out_file, key, iv)
File "C:/Users/saeed/IdeaProjects/encryptor/encryption.py", line 15, in 
encrypt
chunk += padding_length * chr(padding_length)
TypeError: can't concat bytes to str

这是什么意思，我该如何修复？

Answer 1

从文件读取时，读取数据的类型是bytes类型而不是str类型。如果您使用chunk += bytes( padding_length )，则将填充物附加到块上。