Qr code scan screen lock

Hi guys, new guy here. I was wondering if it's possible for someone to code a screen lock which basically needs a qr code to be scanned to unlock. I thought it would be cool to hover your camera on a qr code tattoo/sticker on your body to open your phone.
I'd just like to point out that I don't have any idea on coding and programming what so ever. So if you will respond to my question I'm begging you to go easy with the coding/programming terms as for those are completely alien language to me.

from Android Authority Forums http://ift.tt/292DvbD
via IFTTT