Script mã hoá và giải mã file bằng AES256

encrypt_file.py

"""
Ma Hoa AES256. Dung cho python 3.5+
Can cai dat pycryptodome. https://pypi.org/project/pycryptodome/
Script nay co su dung code tu: https://eli.thegreenplace.net/2010/06/25/aes-encryption-of-files-in-python-with-pycrypto/
"""
import os, random, struct
import hashlib
from Crypto.Cipher import AES


def encrypt_file(key, in_filename, out_filename=None, chunksize=64*1024):
    """ Encrypts a file using AES (CBC mode) with the
        given key.

        key:
            The encryption key - a string that must be
            either 16, 24 or 32 bytes long. Longer keys
            are more secure.

        in_filename:
            Name of the input file

        out_filename:
            If None, '<in_filename>.enc' will be used.

        chunksize:
            Sets the size of the chunk which the function
            uses to read and encrypt the file. Larger chunk
            sizes can be faster for some files and machines.
            chunksize must be divisible by 16.
    """
    if not out_filename:
        out_filename = in_filename + '.enc'

    iv = ''.join(chr(random.randint(0, 0xFF)) for i in range(16))
    iv = hashlib.sha256(iv.encode('utf-8')).digest()[:16]
    encryptor = AES.new(key, AES.MODE_CBC, iv)
    filesize = os.path.getsize(in_filename)

    with open(in_filename, 'rb') as infile:
        with open(out_filename, 'wb') as outfile:
            outfile.write(struct.pack('<Q', filesize))
            outfile.write(iv)

            while True:
                chunk = infile.read(chunksize)
                if len(chunk) == 0:
                    break
                elif len(chunk) % 16 != 0:
                    chunk += b' ' * (16 - len(chunk) % 16)

                outfile.write(encryptor.encrypt(chunk))

def decrypt_file(key, in_filename, out_filename=None, chunksize=24*1024):
    """ Decrypts a file using AES (CBC mode) with the
        given key. Parameters are similar to encrypt_file,
        with one difference: out_filename, if not supplied
        will be in_filename without its last extension
        (i.e. if in_filename is 'aaa.zip.enc' then
        out_filename will be 'aaa.zip')
    """
    if not out_filename:
        out_filename = os.path.splitext(in_filename)[0]

    with open(in_filename, 'rb') as infile:
        origsize = struct.unpack('<Q', infile.read(struct.calcsize('Q')))[0]
        iv = infile.read(16)
        decryptor = AES.new(key, AES.MODE_CBC, iv)

        with open(out_filename, 'wb') as outfile:
            while True:
                chunk = infile.read(chunksize)
                if len(chunk) == 0:
                    break
                outfile.write(decryptor.decrypt(chunk))

            outfile.truncate(origsize)

def main():
    huongdan = """Bat buoc su dung python 3.5 tro len. \n\n
File sau khi duoc ma hoa se co dang <tenfile.enc> .\n Vi du: file <abcd.rar> sau khi duoc ma hoa se tao ra file <abcd.rar.enc>\n\n
File sau khi duoc giai ma se co ten file bi loai bo phan duoi.\nVi du: file <abcd.rar.enc> sau khi duoc giai ma se tao ra file <abcd.rar>\n\n"""
    z = input("Chon 1 hoac 2 hoac 3. [1] encrypt (Ma Hoa), [2] decrypt (Giai Ma), [3] Huong dan: ")
    if int(z) == 3:
        print(huongdan)
        return
    if int(z) == 2:
        x = input("Nhap password: ")
        y = input("Nhap duong dan den file can ma hoa / giai ma: ")
        in_filename = y.replace("\\", "/")
        key = hashlib.sha256(x.encode('utf-8')).digest()
        decrypt_file(key, in_filename, out_filename=None, chunksize=24*1024)
    if int(z) == 1:
        x = input("Nhap password: ")
        x1 = input("Nhap lai password: ")
        if x != x1:
            print("password khong trung voi password o tren!!!! EXIT!!!")
            return
        y = input("Nhap duong dan den file can ma hoa / giai ma: ")
        in_filename = y.replace("\\", "/")
        key = hashlib.sha256(x.encode('utf-8')).digest()
        encrypt_file(key, in_filename, out_filename=None, chunksize=64*1024)
if __name__ == '__main__':
    main()