Here we go! 🚀

So can I have a little ring that's BLE and it has a button (not physical, but react to tap) and if my phone makes a request for signing and I press the ring in the next 5 seconds, it signs?

Not sure the BLE rings would have enough program memory to hold the library required to sign it unfortunately. But you can have a separate device like the LilyGo T-Display-S3 that holds your private key so your apps don’t need it or ever see it.

If they manage to pack something like this, that should be enough? Would the nip support the interaction as I described it? https://www.nordicsemi.com/Products/nRF5340

Yeah, the NIP describes the protocol to send and retrieve data. So in theory your tap of the ring would be the tap to sign. You’d have to trust that the note/data being signed is what you sent to it though as you’d have no screen to validate.

The chip though only has 1mb flash and 512kb ram so it would be hard to implement.