Question

我有一个存储用户凭据的文件。我计划对其进行一次加密，然后在需要从文件中获取凭据时再执行解密和加密过程.Below是我原始文件的内容

{"customer1": {"tool_id": "earth", "user": "myuser", "pwd": "mypwd", "acc_id": "myaccount", "app_id": "myapp"}}
{"customer2": {"tool_id": "venus", "app_id": "myapp2", "api_key": "mykey"}}

我有以下程序来进行加密和解密

import os
from Crypto.Cipher import AES
from Crypto.Hash import SHA256
from Crypto import Random


def encrypt(key, filename):
    chunksize = 64 * 1024
    outputFile = "credentials.txt"
    filesize = str(os.path.getsize(filename)).zfill(16)
    IV = Random.new().read(16)

    encryptor = AES.new(getKey(key), AES.MODE_CBC, IV)

    with open(filename, 'rb') as infile:
        with open(outputFile, 'wb') as outfile:
            outfile.write(filesize.encode('utf-8'))
            outfile.write(IV)

            while True:
                chunk = infile.read(chunksize)

                if len(chunk) == 0:
                    break
                elif len(chunk) % 16 != 0:
                    chunk += b' ' * (16 - (len(chunk) % 16))

                outfile.write(encryptor.encrypt(chunk))


def decrypt(key, filename):
    chunksize = 64 * 1024
    outputFile = filename

    with open(filename, 'rb') as infile:
        filesize = int(infile.read(16))
        IV = infile.read(16)

        decryptor = AES.new(getKey(key), AES.MODE_CBC, IV)

        with open(outputFile, 'wb') as outfile:
            while True:
                chunk = infile.read(chunksize)

                if len(chunk) == 0:
                    break

                outfile.write(decryptor.decrypt(chunk))
            outfile.truncate(filesize)


def getKey(password):
    hasher = SHA256.new(password.encode('utf-8'))
    return hasher.digest()

我计划对我的文件使用相同的命名约定来进行加密和解密。

第一次进行加密时

encrypt("poplo1234", "credentials.txt")

能够进行加密（对于相同的文件名）

当我尝试解密时

decrypt("poplo1234", "credentials.txt")

无法执行此操作。但是，在加密时，如果我为生成的新文件指定了不同的文件名并对其进行解密，则可以正常工作。

为什么我遇到这样的行为？我怎样才能确保多次使用相同的文件名进行加密和解密。

Answer 1

问题是尝试同时读取和写入同一文件。解决方案是写入临时文件，关闭文件后重命名临时文件。

Answer 2

这是一个对我有用的例子！该脚本采用一个zip文件等。hello.zip使用名称hello.zip.enc对其进行加密，然后使用名称hello_end.zip对其进行解密。

from Crypto.Cipher import AES

key = '0123456789abcdef'
IV = 16 * '\x00'         # Initialization vector: discussed later
mode = AES.MODE_CFB
encryptor = AES.new(key, mode, IV=IV)

file = open("hello.zip", "rb")
text = file.read()
file.close()
ciphertext = encryptor.encrypt(text)

encr_file = open("hello.zip.enc", "wb")
encr_file.write(ciphertext)
encr_file.close()


final_file = open("hello.zip.enc", "rb")
xen_text = final_file.read()
plaintext = encryptor.decrypt(xen_text)
final_file.close()


end = open("hello_end.zip", "wb")
end.write(plaintext)
end.close()

使用CFB模式以免弄乱填充

无法使用一致的命名加密和解密文件

2 个答案: