fernet.py

#!/usr/bin/env python
from cryptography.fernet import Fernet
import argparse


parser = argparse.ArgumentParser()
parser.add_argument("-f", "--fernet", required=True,help="Fernet Key")
parser.add_argument("-v", "--val", required=True,help="Value to decode")
args = parser.parse_args()

KEY = args.fernet
VAL = bytes(args.val, 'utf-8')

def decrypt_message(encrypted_message,KEY):
    """
    Decrypts an encrypted message
    """
    f = Fernet(KEY)
    decrypted_message = f.decrypt(encrypted_message)

    print(decrypted_message.decode())

if __name__ == "__main__":
   decrypt_message(VAL,KEY)