crypto.py

from cryptography.fernet import Fernet
import base64

def encrypt_pdf(pdf_bytes, key):
    cipher = Fernet(base64.urlsafe_b64encode(key.ljust(32)[:32]))
    return cipher.encrypt(pdf_bytes)

def decrypt_pdf(encrypted_bytes, key):
    cipher = Fernet(base64.urlsafe_b64encode(key.ljust(32)[:32]))
    return cipher.decrypt(encrypted_bytes)