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@eoli3n
Last active May 28, 2024 02:47
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Encrypt - Decrypt AES from/to Python PyCryptodome from/to PHP openssl
<?php
// use to generate key : 'openssl rand -hex 32'
function my_encrypt($data, $passphrase) {
$secret_key = hex2bin($passphrase);
$iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length('aes-256-cbc'));
$encrypted_64 = openssl_encrypt($data, 'aes-256-cbc', $secret_key, 0, $iv);
$iv_64 = base64_encode($iv);
$json = new stdClass();
$json->iv = $iv_64;
$json->data = $encrypted_64;
return base64_encode(json_encode($json));
}
function my_decrypt($data, $passphrase) {
$secret_key = hex2bin($passphrase);
$json = json_decode(base64_decode($data));
$iv = base64_decode($json->{'iv'});
$encrypted_64 = $json->{'data'};
$data_encrypted = base64_decode($encrypted_64);
$decrypted = openssl_decrypt($data_encrypted, 'aes-256-cbc', $secret_key, OPENSSL_RAW_DATA, $iv);
return $decrypted;
}
#!/usr/bin/env python3
# pip install pycryptodome
import json
import binascii
from Crypto.Cipher import AES
from Crypto import Random
import base64
def my_encrypt(data, passphrase):
"""
Encrypt using AES-256-CBC with random/shared iv
'passphrase' must be in hex, generate with 'openssl rand -hex 32'
"""
try:
key = binascii.unhexlify(passphrase)
pad = lambda s : s+chr(16-len(s)%16)*(16-len(s)%16)
iv = Random.get_random_bytes(16)
cipher = AES.new(key, AES.MODE_CBC, iv)
encrypted_64 = base64.b64encode(cipher.encrypt(pad(data).encode())).decode('ascii')
iv_64 = base64.b64encode(iv).decode('ascii')
json_data = {}
json_data['iv'] = iv_64
json_data['data'] = encrypted_64
clean = base64.b64encode(json.dumps(json_data).encode('ascii'))
except Exception as e:
print("Cannot encrypt datas...")
print(e)
exit(1)
return clean
def my_decrypt(data, passphrase):
"""
Decrypt using AES-256-CBC with iv
'passphrase' must be in hex, generate with 'openssl rand -hex 32'
# https://stackoverflow.com/a/54166852/11061370
"""
try:
unpad = lambda s : s[:-s[-1]]
key = binascii.unhexlify(passphrase)
encrypted = json.loads(base64.b64decode(data).decode('ascii'))
encrypted_data = base64.b64decode(encrypted['data'])
iv = base64.b64decode(encrypted['iv'])
cipher = AES.new(key, AES.MODE_CBC, iv)
decrypted = cipher.decrypt(encrypted_data)
clean = unpad(decrypted).decode('ascii').rstrip()
except Exception as e:
print("Cannot decrypt datas...")
print(e)
exit(1)
return clean
@sdamediadev
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ah I see @mxmfrlv thank you very much, I remember when I implemented the encryption above in my python code, it's not working with hex 32, so I am using hex 16.

then when I change the algorithm from AES-256-CBC to AES-128-CBC, it's now working.

@ruimelodev
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ruimelodev commented Nov 23, 2022

This is returning an error when I try to encrypt alphabet characters with diacritics in Python.
Example:

my_encrypt("Crème Brûlée", "hash")
# Output:
# Data must be padded to 16 byte boundary in CBC mode

Is there a way for me to have this method accept all types of characters?

@mspi21
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mspi21 commented Apr 1, 2024

Security considerations

You are aware of the fact that the parameters that you're referring to as "passphrases" are really not passphrases, but cryptographic keys, which have to consist of cryptographically strong random bytes, are you not?

You can generate symmetric encryption keys directly in your code (maybe via a separate function, e.g. generate_secure_encryption_key()) using the same way you're generating your initialization vectors, i.e. through Crypto.Random (or alternatively, os.urandom). The key needs to then be stored somewhere safe, e.g. a file readable only by its owner.

If you need to use a passphrase for encryption, such as the string "a quick brown fox jumps over the lazy dog", you need to use a key derivation function to transform your passphrase into a suitable key.

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