Windows 10 already does a lot to spare you from typing in your password, but Microsoft wants to take that text-free login one step further. The company has quietly posted a beta Phone Sign-in app for Windows 10 Mobile that, as the name suggests, signs you in to your nearby Windows 10 PC (you have to pair over Bluetooth) with a tap. There's no guarantee that you can run it -- you'll need the right credentials on top of living in an all-Microsoft ecosystem. If all the stars align, though, the Lumia in your pocket might be all you need to authenticate and start working.