I'm looking of some kind of solution that enables me to print some kind of "encrypted" QR codes, so scanning of it with regular QR-code reader will display non-sense, but scanning with some "special" QR-code reader in which I enter some kind of "decryption key", will display correct text.
I'm not looking to real good encryption, just some kind of "security-by-obscurity" or "just XOR" will work for me. It isn't meant to resists vs dedicated hacker, only to create some barrier.
It should be fairly easy programmed, but I rather using existing solution, preferable some form of Android Application.