Two-dimensional code (abbreviation of quick response code) is the trademark of matrix barcode (or two-dimensional barcode) designed for Japanese automobile industry for the first time in 1994. Bar code is a machine-readable optical label, which contains information related to the attached items. In fact, QR codes usually contain data pointing to locators, identifiers or trackers of websites or applications. Two-dimensional code uses four standardized coding modes (numeric, alphanumeric, byte/binary and Chinese characters) to store data efficiently, and can also use extensions.

Scanning refers to the function of scanning a QR code with a mobile phone to add friends, pay, download mobile phone applications, verify information and obtain relevant information. Wechat and some mobile phone software have this function. In daily life, you can add WeChat friends, download coupons, buy tickets, browse the web, download mobile applications and so on. "Sweep" with mobile phones, and some people even make their own personal business cards with QR codes. "As long as there is WeChat or QR code reading software on the mobile phone, you can read the QR code with your consciousness." Wang Pengfei, Chairman and CEO of Smart Company, said that QR codes not only bring convenience to users, but also have information security loopholes.