leorodriadv / loyalt-card Goto Github PK

Ok can anyone help me? I have a loyalty app in Brazil called Jambalaio! But in the commercial part I have a problem! It works like this! The User downloads the app, and will have a code, this code is his forever in all establishment! The problem with my business is that the merchant needs to have the Admin App open to send the stamps so the user speaks the code and the merchant owner puts the code in and sends the stamp to the customer! The owner wants something simpler, he doesn't need to have the app admin open, i'll do an update i thought the QR code, ie the owner left a QR code already printed but here comes a new problem that is the trust of the owner of the establishment, ie he is afraid that someone might take the picture of the QR code and put codes, or that the clerks send more codes to users! I wanted something for the user to download the App and get close with the phone and automatically get the stamp, something that could not be used 2x or something that can only be used after 24 hours! I arrived at NFC Technology but I don't know if that would give me more work than a QR code! My question is, do you have anything that can help me? any secure technology that I could talk to the owner of the secure establishment? Can I make the QR code only be used 1x by users for 24 hours? If so how to program? Thanks Leonardo