Principles of health laws and regulations
The health code can record the trajectory of your daily actions through the big data in the background of your mobile phone. Then enter the database of big data. Once there are infected or suspected patients in the database, the background big data will automatically calculate and compare, and screen out the data of people who have crossed the track with the confirmed patients or suspected patients.
The health code color of people who are closely related to it will change color, which is a simple understanding. More depends on the calculation data of big data in the background, rather than a QR code picture in a simple mobile phone.