PEM

Android requires developers to sign their applications with a digital certificate and that each future release be signed with the same certificate.

Sadly, bad things happen when the developer (you) looses access to the certificate : he (you) will not be able to release updates for the application without it. Never. Ever.

Android does not currently support multiple certificates per application so the best you could do would be to release a new app with the same name, in the hope your users will find a way to it by themselves.

As years go on, you will change your computer, wipe USB keys, reinstall OS, ...
So many dangerous operations for your digital certificates, hidden among millions of files !
If, like me, you are anxious at the idea of losing your certificates or passwords, just print a paper copy !
Although it is not invulnerable, paper should be less prone to mass erasing than a simple electronic file.

The idea is simple, not new, and you just need to know two commands to get a printable hard copy of your certificate.

Let's start.