How'd your scheme work? I suspect HN wants to know ;) A lot of hardware just acts as HID keyboard, but that only works one direction unless you use a side chann

How'd your scheme work? I suspect HN wants to know ;) A lot of hardware just acts as HID keyboard, but that only works one direction unless you use a side channel like visual (QR code like TOTP and/or camera like the Bloomberg unit). I think the Bloomberg auth units are some of the most advanced examples of this - they're protected against almost any imaginable physical attack, too (freezing memory state, power sidechannels, xray/delidding to dump mask ROM, etc.) But they have a lot of money to spend on it...