HTTPS to transmit data from embedded device (read only filesystem)?



I’m developing a small embedded device for my own use. This device is intended to transmit log data on daily base to a remote server via GSM/UMTS connection. Is it possible to encrypt this connection using a Let’s Encrypt certificate on my webserver?

What do I have to have on the embedded device? It seems like the Let’s Encrypt root certificate is only valid until 2020-06-04. The system runs unattended. The filesystem is read only and there is no plan to update something regularly. Is an operation possible even without having to update something? Will my certificates still verify even if the root certificate expires? Or is SSL/HTTPS no option for my use case?

Thanks in advance.


You should really consider to use your own self signed certificate, and put your own CA manually onto your embedded device. I guess your embedded device does not trust any CA by default, so you can just make your own, and add it to your https client on the device.

Just a tip: Use easy-rsa, to generate your CA and server certificate.


Thank you for the hint. I found instructions on how to do this with plain openssl. Seems to work well.


Its good to help, good luck for your project!