### Use live code
The live code means that using methods such as LED, the current QR code on the dining table will change every time the code is scanned, and the generated QR code will also change. This can effectively prevent the QR code from being photographed and maliciously scanning the code to order food.
### Use GPS location distance limits
You can obtain the current location of the user who scans the QR code and calculate the distance to the restaurant. You can order food only if the distance is within 200 meters.