CODEWITHSUNDEEP
pythonpython-3.xencryptionpycryptopycryptodome
maribor
maribor

Reputation: 31

Probles with AES encrypting. cant decrypt with a right key

I'm trying to decrypt encrypdet data. Data was encrypted with AES CBC mode using pycryptodome lib. Have a such error - "ValueError: Incorrect AES key length (256 bytes)

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

class AESCipher:
    def __init__(self, key):
        pass

    def pad(self, s):
        return s + b"\0" * (AES.block_size - len(s) % AES.block_size)

    def encrypt(self, message, key, key_size=256):
        message = self.pad(message)
        iv = Random.new().read(AES.block_size)
        cipher = AES.new(key, AES.MODE_CBC, iv)
        return iv + cipher.encrypt(message)

    def decrypt(self, ciphertext, key):
        iv = ciphertext[:AES.block_size]
        cipher = AES.new(key, AES.MODE_CBC, iv)
        plaintext = cipher.decrypt(ciphertext[AES.block_size:])
        return plaintext.rstrip(b"\0")

def send_data(data)
    key = os.urandom(16)
    cipher = AESCipher(key)
    ciphertext = cipher.encrypt(data, key)
    return key, ciphertext

def receive_data(key, data):
    cipher = AESCipher(key)
    decrypted = cipher.decrypt(data, key)
    return decrypted

data = b'12 43 42 46 af'
key, ciphertext = send_data(data)
decrypted = receive_data(key, data)

Upvotes: 1

Views: 667

Answers (1)

y.luis.rojo
y.luis.rojo

Reputation: 1824

I think that what you want to decrypt is the ciphered text, not the original data (non-encrypted):

decrypted = receive_data(key, ciphertext)

Upvotes: 2

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