Securing Firebase outgoing webhooks

Hi All!

I'm currently making a bot using botbuilder which connects to a firebase (thank you to everyone who suggested this in my last question!) backend. There aren't any security concerns to my knowledge with the connection from bot to firebase database as I'm using the firebase admin SDK from the bot side.

I would like to send proactive messages to the bot from a pubsub function on the firebase side. I think this will need therefore to be a http post request somewhere. I know I'll have to encrypt this and wondering if anyone has come across this issue before and encrypted and then validated on the bot (client) side.

I've seen an approach of creating your own shared secret and encrypting yourself here,

https://www.agrenpoint.com/azurebot-nodejs-part8/

however I was wondering if there is a best practice/ approach that doesn't rely on my limited security knowledge

Thanks for the help!