2. Source: Based on real data, citizens or people who have returned to work can generate personal QR codes through their online declaration and background audit. As an individual entering and leaving electronic certificate locally, the QR code can be declared once, which is universal in the whole city.
3. Classification: There are three types of "health codes": green codes can be entered directly, red codes can be isolated for 14 days, and yellow codes can be isolated for less than 7 days. The "health code" management information system is based on real data, connected with relevant databases such as the dynamic control list of key personnel, and distributes "health codes" according to the results of verification and comparison between mass declaration information and background data.