I want some QR codes but they should be one time scanable. Basically it should show a specific message on first scan and a different message (eg: ERROR) if scanned again.
1 freelancer is bidding on average ₹1500 for this job
I am a computer science guy so pretty much easy for me. I have done many qr code scans in the past and know the hexadecimal number system which is the basic of generating a qr code.