Adding signup and login features?

Any thoughts or interest in this? Our InformaCam "CameraV" app uses PGP to sign and encrypt media metadata, and we'd like to make it really easy for users to backup, share, and find keys via Keybase. 

We can do the last part with your library as it stands now, but not the other parts.

Thanks for all this work, and the various write-ups, etc you posted. Good stuff!
