Encode in Laravel, decode in Python

Question

I\'m using Laravel\'s encryptString method to encrypt some data on my website. This uses OpenSSL\'s 256-bit AES-CBC encryption without any serialization. I\'m now trying to decr

Answer 1

Question: ...trying to decrypt that data in Python but I keep getting errors about key length

I can use your key, in the code of the linked answer, after doing .b64decode(....
The example code .encode(... and decode(... works as expecte.
Conclusion: There is nothing wrong, with your Key!

key = b"/AZejP0lh3McL/+Vy5yZcADdTcR65qnx5Jqinuw7raK="
key = base64.b64decode(key)

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But with your code, I got TypeError, related to the IV parameter:

  expect_byte_string(iv)
File "/usr/local/lib/python3.4/dist-packages/Crypto/Util/_raw_api.py", line 172, in expect_byte_string
  TypeError: Only byte strings can be passed to C code

Fixed with IV = 16 * '\x00'.encode(), results in ValueError, related to enc:

  data = decobj.decrypt(base64.b64decode(enc))
File "/usr/local/lib/python3.4/dist-packages/Crypto/Cipher/_mode_cbc.py", line 209, in decrypt
  ValueError: Error 3 while decrypting in CBC mode

This leads to github issues:10

Error 3 means "ERR_NOT_ENOUGH_DATA"

According to the linked GitHub page, you have to reread the documentation, about padding data while you are encoding.

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Working example from GitHub:

import base64
from Crypto.Cipher import AES
from Crypto.Util.Padding import pad, unpad

key = b"/AZejP0lh3McL/+Vy5yZcADdTcR65qnx5Jqinuw7raK="
key = base64.b64decode(key)

BLOCK_SIZE = 32
encryption_suite = AES.new(key, AES.MODE_CBC, b'This is an IV...')
cipher_text = encryption_suite.encrypt(pad(b'A really secret message...', BLOCK_SIZE))

decryption_suite = AES.new(key, AES.MODE_CBC, b'This is an IV...')
print(unpad(decryption_suite.decrypt(cipher_text), BLOCK_SIZE).decode())
>>> A really secret message...

Tested with Python: 3.4.2