Support for integration of state issued certificates

[mitar]

In some European countries (to my knowledge, maybe also elsewhere) governments are issuing certificates which can serve as a way to sign documents with digital signatures which are legally equivalent to normal signatures.

The issue is that there is little support for tooling around such certificates (which are normal public/private keypair, signed by state CA). So it would be great if one could integrate them somehow into keybase ecosystem so that you could:

• prove your keybase identity by signing it with the state-issues certificate
• could alternatively use state-issued key pair for your keybase signatures (so that you could use all common keybase tools, just use state-issued key pair to sign documents, for example)

[pkirkovsky]

Are these like Estonian IDs, which are basically full-size SIM smartcards with a photo? Those can integrate with OpenSC and therefore GPG: https://github.com/OpenSC/OpenSC/wiki/Estonian-eID-%28EstEID%29

[mitar]

In my case (Slovenia) there are simply signed certificates. You can use a smart card to store them, but it is not required.

[mitar]

Related: #1732.

[grawity]

@pkirkovsky, it's not the card that matters, but the certificate in it – "integrating with GPG" would defeat the whole point.