[amartya916]

"I can imagine a future when many people only have a watch as their personal device but use other larger devices that are shared, instantly personalized by a watch."

This is a good idea succinctly put. Thank you. The building blocks are already there (e.g. Apple watch based unlocking for the Mac), and can be extended to spaces like the automobile (CarPlay, extending your definition of a "device" to cars).

[walterbell]

Is there an open-standard way for an Apple Watch to unlock a Linux workstation or IoT device?

[r00fus]

It's a generally bad idea (due to auth options for the watch itself). However it's a great 2nd factor.

[amartya916]

As far as I know, there are no open APIs from Apple that’ll help. However, I think it might be possible to use Bluetooth Low Energy (BLE) ranging as a proxy for distance. Whether the Watch acts as a BLE beacon or the linux laptop or IoT does the same (or vice-versa) is something to tinker with.