I am building a stand-alone system - not connected to the general internet - consisting of a web server, WiFi network and standard Android tablet. The web server needs to support https because I need to read the tablet’s GPS coordinates (using html 5), which are nowadays only available to a secure website.
Let’s Encrypt certificates would be ideal, except that it will not be possible to automatically renew certificates to to no internet connection. The system will be deployed in the field where I will have no access to it.
One alternative are self-signed certificates, but these generate warnings on the tablet that cannot easily be suppressed (It is possible, but the procedure is complicated and may require root access).
What I would really like to use in this situation is a certificate with a very long duration, say more than 10 years.
Is there any chance that such certificates will become available in the near future?
Are there any alternative solutions for this use case?