You may as well just delete it, then. I guarantee a high percentage of users won't save that key and be able to find it later. GH (edit: or similarly nerdy site

You may as well just delete it, then. I guarantee a high percentage of users won't save that key and be able to find it later. GH (edit: or similarly nerdy sites) might (might!) be able to get away with that, but as soon as part of your process is "give the user a cryptographic key" you've just guaranteed yourself a support nightmare, with normal users. It's why the only cryptographic person-to-person communication systems that've been broadly successful haven't involved keeping track of anything, and don't have a setup process more complex than "point camera at QR code".