M2Crypto Encryption / Decryption using AES256

Question

Can someone provide me code for encryption / decryption using m2crypto aes256 CBC using Python

Answer 1

The M2Crypto documentation is terrible. OpenSSL documentation (m2crypto wraps OpenSSL) can sometimes help. It's best to take a look at the M2Crypto unit tests - https://gitlab.com/m2crypto/m2crypto/blob/master/tests/test_evp.py - look for the test_AES() method.

Answer 2

Take a look at m2secret :

A small utility and module for encrypting and decrypting data using symmetric key algorithms. By default, it uses 256-bit AES (Rijndael) using CBC, but some parameters are configurable. PBKDF2 algorithm used to get the password key.

Answer 3

 def encrypt_file(key, in_filename, out_filename,iv): cipher=M2Crypto.EVP.Cipher('aes_256_cfb',key,iv, op=1) with open(in_filename, 'rb') as infile: with open(out_filename, 'wb') as outfile: outfile.write(b) while True: buf = infile.read(1024) if not buf: break outfile.write(cipher.update(buf)) outfile.write( cipher.final() ) outfile.close() infile.close() def decrypt_file(key, in_filename, out_filename,iv): cipher = M2Crypto.EVP.Cipher("aes_256_cfb",key , iv, op = 0) with open(in_filename, 'rb') as infile: with open(out_filename, 'wb') as outfile: while True: buf = infile.read(1024) if not buf: break try: outfile.write(cipher.update(buf)) except: print "here" outfile.write( cipher.final() ) outfile.close() infile.close() 

Answer 4

I use the following wrapper around M2Crypto (borrowed from cryptography.io ):

 import os import base64 import M2Crypto class SymmetricEncryption(object): @staticmethod def generate_key(): return base64.b64encode(os.urandom(48)) def __init__(self, key): key = base64.b64decode(key) self.iv = key[:16] self.key = key[16:] def encrypt(self, plaintext): ENCRYPT = 1 cipher = M2Crypto.EVP.Cipher(alg='aes_256_cbc', key=self.key, iv=self.iv, op=ENCRYPT) ciphertext = cipher.update(plaintext) + cipher.final() return base64.b64encode(ciphertext) def decrypt(self, cyphertext): DECRYPT = 0 cipher = M2Crypto.EVP.Cipher(alg='aes_256_cbc', key=self.key, iv=self.iv, op=DECRYPT) plaintext = cipher.update(base64.b64decode(cyphertext)) + cipher.final() return plaintext 

Answer 5

When it comes to security, nothing beats reading the documentation.

http://chandlerproject.org/bin/view/Projects/MeTooCrypto

Even if I took the time to understand and make the perfect code for copy and paste, you would have no idea if I had done a good job or not. Not very useful, I know, but I wish you good luck and reliable data.