Should be nip-07, if you mean allowing people to sign into your website
Discussion
I don't think this covers authentication, just signing events?
It will open the extension and ask how long they’d like to give access. This might be a good example:
https://github.com/leesalminen/nostr-bulk-dm/blob/main/src/App.js
Yea extension don’t do auth. Only sign events. I was looking at this last week. Haven’t tried anything.
What's the difference in your opinion? Can you use a NIP 07 extension with only a public key?