LoRaWAN without server

[giam]

Hi,
I'd like to create a LoRaWAN network with a gateway that takes care of receiving the data from the nodes and acknowledging them without going through a server (e.g. TTN).
I want to use LoRaWAN (rather than LoRa-MAC) to take advantage of encryption etc...
So, from the gateway, once I receive the data, what's the best way to decrypt it and then reply to the node that sent it?
Thanks!

[giam]

Thanks @jmarcelino.
Thus the encryption part is not something you get for free... At this point, would it still make sense to prefer LoRaWAN over LoRa-MAC for a standalone network?

[jmarcelino]

@giam
To decrypt it may be possible to port the crypto library from lora-python to MicroPython: https://github.com/jieter/python-lora/blob/master/lora/crypto.py

Alternatively another good resource would be the node.js LoRa Packet decoder:
https://github.com/anthonykirby/lora-packet

Then to reply to the node you'll need to encrypt it.