I want to have an NFC sticker on my laptop/desktop which when swiped with my NFC phone will unlock my computer. If I don't have my phone with me, I can still login using my normal password. I so far bought some NFC stickers and installed TagStand on my phone which manages to post to a server that I control. I want to write some small piece of software that would listen to this server and unlock my computer if the server tells my computer to do so. I have not made the last part work as I don't know how to write such a software for either Mac or PC. Is it possible? If so, how?
The NFC part is very simple but the unlocking part is more complicated than you think. Unlocking your computer should never be done programmatically because if your program can do it, then so can others. Not to mention that this 'program' is going to act based on communication between a remote server and itself. This is a security nightmare, that has no use other than the experimental benefit.
If you do enough research you'll find that locking (not unlocking) a computer is possible programmatically. Unlocking on the other hand is not easy..
Here are a few links for you, I've been though them before, never tested them though...
Remotely-Unlock-a-Windows-Workstation
unlock-local-computer-using-net