OwnTracks Python decrypt function

owntracks python decrypt.py

import base64
from libnacl import crypto_secretbox_KEYBYTES as KEYLEN
from libnacl.secret import SecretBox


def decrypt_payload(payload):
    key = 'abcedf'.encode('utf-8')
    key = key.ljust(KEYLEN, b'\0')

    ciphertext = base64.b64decode(payload)
    return SecretBox(key).decrypt(ciphertext).decode('utf-8')

posted_data = json.loads(request.body.decode('utf-8'))
posted_data = decrypt_payload(posted_data['data'])
posted_data = json.loads(posted_data)