des.py

# -*- coding: utf-8 -*-


from cryptography.fernet import Fernet

def write_key():
    """
    Generates a key and save it into a file
    """
    key = Fernet.generate_key()
    with open("key.key", "wb") as key_file:
        key_file.write(key)
        
def load_key():
    """
    Loads the key from the current directory named `key.key`
    """
    return open("key.key", "rb").read()

write_key()

key = load_key()






def encrypt(filename, key):
    """
    Given a filename (str) and key (bytes), it encrypts the file and write it
    """
    f = Fernet(key)
    with open(filename, "rb") as file:
        # read all file data
        file_data = file.read()
        
        # encrypt data
    encrypted_data = f.encrypt(file_data)
        
        # write the encrypted file
    with open(filename, "wb") as file:
        file.write(encrypted_data)

def decrypt(filename, key):
    """
    Given a filename (str) and key (bytes), it decrypts the file and write it
    """
    f = Fernet(key)
    with open(filename, "rb") as file:
        # read the encrypted data
        encrypted_data = file.read()
    # decrypt data
    decrypted_data = f.decrypt(encrypted_data)
    # write the original file
    with open(filename, "wb") as file:
        file.write(decrypted_data)
        


encrypt('mysong_1.mp3',key)
decrypt('mysong_1.mp3',key)