Updating trust anchors on-the-fly

[bvanpoortvliet]

Hi,

We are using Teensy 4.1's to post device metrics to an influxDB instance hosted on AWS over HTTPS. Since AWS renews it's certificates every quarter, this would mean the trust anchors in the Teensy's need to be updated as well.

Considering these Teensy's will be deployed in the field and spread over a variety of countries, we do not have the luxury to reflash these devices every time the AWS certificates expire and are therefor in need of a system that would enable us to update the trust anchors on-the-fly.

As per @khoih-prog's suggestion in my issue here we will start with the following:

1. Creating an HTTP/HTTPS server with updated trust anchors
2. Update the server trust anchors by writing a program / script to check with AWS
3. Teensy will periodically check and auto-update the trust anchors whenever there is mismatch (using checksum, etc.) between local and server's trust anchors. Anyway, trust anchors is just a piece of manageable array of bytes.

I will post our future findings here, any information or recommendations on this topic are welcome!