L�m th? n�o d? m� h�a c�c t?p tin b?ng c�ch s? d?ng Python / PyCrypto theo m?t c�ch tuong th�ch v?i OpenSSL?

T? d� t�m t�i r?t nhi?u ? tr�n m?ng, cung nhu c�c t�i nguy�n kh�c, d? l�m cho n� d�ng theo v?i b�i vi?t m� m�nh kham kh?o du?c v� nghi r?ng t? c� th? chia s? cho m?i ngu?i d? c� k?t qu? d? tham kh?o trong tuong lai v� c� l? xem l?i n� v� ch?c ch?n s? gi�p m?t s? b?n c� th�m t�i li?u h?c t?p !!!

python

from hashlib import md5

from Crypto.Cipher import AES
from Crypto import Random

def derive_key_and_iv(password, salt, key_length, iv_length):
    d = d_i = ''
    while len(d) < key_length + iv_length:
        d_i = md5(d_i + password + salt).digest()
        d += d_i
    return d[:key_length], d[key_length:key_length+iv_length]

def encrypt(in_file, out_file, password, key_length=32):
    bs = AES.block_size
    salt = Random.new().read(bs - len('Salted__'))
    key, iv = derive_key_and_iv(password, salt, key_length, bs)
    cipher = AES.new(key, AES.MODE_CBC, iv)
    out_file.write('Salted__' + salt)
    finished = False
    while not finished:
        chunk = in_file.read(1024 * bs)
        if len(chunk) == 0 or len(chunk) % bs != 0:
            padding_length = (bs - len(chunk) % bs) or bs
            chunk += padding_length * chr(padding_length)
            finished = True
        out_file.write(cipher.encrypt(chunk))

def decrypt(in_file, out_file, password, key_length=32):
    bs = AES.block_size
    salt = in_file.read(bs)[len('Salted__'):]
    key, iv = derive_key_and_iv(password, salt, key_length, bs)
    cipher = AES.new(key, AES.MODE_CBC, iv)
    next_chunk = ''
    finished = False
    while not finished:
        chunk, next_chunk = next_chunk, cipher.decrypt(in_file.read(1024 * bs))
        if len(next_chunk) == 0:
            padding_length = ord(chunk[-1])
            chunk = chunk[:-padding_length]
            finished = True
        out_file.write(chunk)

Usage:

with open(in_filename, 'rb') as in_file, open(out_filename, 'wb') as out_file:
    encrypt(in_file, out_file, password)
with open(in_filename, 'rb') as in_file, open(out_filename, 'wb') as out_file:
    decrypt(in_file, out_file, password)
��y l� m?t s? do?n script Python s? gi�p b?n m� h�a nh?ng t?p tin c?n du?c b?o m�t, cung nhu d? h?c t?p !