python encrypt/decrypt files

gistfile1.txt

import os
import base64
import cryptography
from cryptography.fernet import Fernet, InvalidToken
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC

def generate_key():
    password_provided = input("password:")
    password = password_provided.encode()  # Convert to type bytes
    salt = b'_salt'  # CHANGE THIS - recommend using a key from os.urandom(16), must be of type bytes
    kdf = PBKDF2HMAC(
        algorithm=hashes.SHA256(),
        length=32,
        salt=salt,
        iterations=100000,
        backend=default_backend()
    )
    key = base64.urlsafe_b64encode(kdf.derive(password))  # Can only use kdf once
    return key

filename = 'xpto'
input_file = './output/'+filename+'.pptx'
output_encrypt_file = './encrypt/'+filename+'.encrypted'

key = generate_key()
#filekey = open('key.key', 'wb')  # Open the file as wb to write bytes
#filekey.write(key)  # The key is type bytes still
#filekey.close()

## ENCRYPT ##
with open(input_file, 'rb') as f:
    data = f.read()  # Read the bytes of the input file

fernet = Fernet(key)
encrypted = fernet.encrypt(data)

fernet = Fernet(key)
encrypted = fernet.encrypt(data)

with open(output_encrypt_file, 'wb') as f:
    f.write(encrypted)  # Write the encrypted bytes to the output file



## DECRYPT ##
output_decrypt_file = './encrypt/'+filename+'.pptx'
key = generate_key()
fernet = Fernet(key)

with open(output_encrypt_file, 'rb') as f:
    data = f.read()  # Read the bytes of the encrypted file

try:
    decrypted = fernet.decrypt(data)

    with open(output_decrypt_file, 'wb') as f:
        f.write(decrypted)  # Write the decrypted bytes to the output file

    # Note: You can delete input_file here if you want
except InvalidToken as e:
    print("Invalid Key - Unsuccessfully decrypted")