在Golang中解密在Python AES CFB中加密的内容

Z时代
2024-01-10
分类：问答

基于Golang关于CFB解密的文档，我写了一个最小的工作示例来解密使用AES

CFB加密的字符串，然后使用python3编码的base 64。

当邮件在Golang中加密（使用Golang doc示例中的加密功能）时，golang解密工作正常。但是，当我使用python

crypto包在python脚本中加密消息时，我无法在golang脚本中成功解密它。我没有得到正确的字节。

$ python3 stack.py Going to encrypt and base64 "This is not encrypted" result: b'jf9A5LCxKWPuNb1XiH+G3APAgR//' Now going to call the Golang script: b'Hello from Golang, going to decrypt: jf9A5LCxKWPuNb1XiH+G3APAgR// Result: Tl!\xca/\xf1\xc0\xb2\xd01Y\x02V\xec\xdf\xecy\xd38&\xd9\n'

两种AES实现的默认块大小为16。

那么问题来了：出了什么问题？

Golang脚本：

package main
import (
    "crypto/aes"
    "crypto/cipher"
    "encoding/base64"
    "fmt"
    "os"
)
func main() {
    key := []byte("TfvY7I358yospfWKcoviZizOShpm5hyH")
    iv := []byte("mb13KcoviZizvYhp")
    payload_python := os.Args[1]
    fmt.Println("Hello from Golang, going to decrypt: "+payload_python+" Result: "+string(decrypt(key, payload_python, iv)))
}
func decrypt(key []byte, cryptoText string, iv []byte) []byte {
    ciphertext, _ := base64.StdEncoding.DecodeString(cryptoText)    //decode base64 coding
    //prepare decryption based on key and iv
    block, _ := aes.NewCipher(key)
    stream := cipher.NewCFBDecrypter(block, iv)
    //decrypt
    stream.XORKeyStream(ciphertext, ciphertext)
    return ciphertext
}

Python脚本：

 #!/usr/bin/env python3
import base64
from Crypto.Cipher import AES
from subprocess import check_output
original_message = 'This is not encrypted'
key = 'TfvY7I358yospfWKcoviZizOShpm5hyH'
iv = 'mb13KcoviZizvYhp'
#prepare encryption
cfb_cipher_encrypt = AES.new(key, AES.MODE_CFB, iv)
#encrypt and base64 encode
encryptedpayload = base64.b64encode(cfb_cipher_encrypt.encrypt(original_message))
print('Going to encrypt and base64 "{}" result:\n{}\n'.format(original_message,encryptedpayload))
print('Now going to call the Golang script:')
print(check_output('go run stack.go {}'.format(encryptedpayload.decode()),shell=True))

回答：

尝试像这样从Python加密。

然后可以从Go成功解密结果。

 #!/usr/bin/env python3
import base64
from Crypto.Cipher import AES
MODE = AES.MODE_CFB
BLOCK_SIZE = 16
SEGMENT_SIZE = 128
def _pad_string(value):
    length = len(value)
    pad_size = BLOCK_SIZE - (length % BLOCK_SIZE)
    return value.ljust(length + pad_size, '\x00')
def encrypt(key, iv, plaintext):
    aes = AES.new(key, MODE, iv, segment_size=SEGMENT_SIZE)
    plaintext = _pad_string(plaintext)
    encrypted_text = aes.encrypt(plaintext)
    return encrypted_text
key = 'TfvY7I358yospfWKcoviZizOShpm5hyH'
iv = 'mb13KcoviZizvYhp'
original_message = 'This is not encrypted'
encryptedpayload = base64.b64encode(encrypt(key, iv, original_message))
print('Going to encrypt and base64 "{}" result:\n{}\n'.format(original_message,encryptedpayload))