Will the QR codes we scan every day be used up one day?

An Jiaran

“Please scan the QR code”, do you often hear or see these words?

Nowadays, QR codes have penetrated into every aspect of life. They are used for payment when shopping, identity registration in public transportation, event tickets, meetings, etc., as well as adding WeChat friends and following public accounts.

What is a QR code?

A QR code is a matrix barcode used to store information. A QR code is usually made up of black and white squares, whose arrangement and color form a coding method that can be quickly read by a scanning device (such as a smartphone or scanner).

Compared with one-dimensional barcodes, the advantages of two-dimensional codes are that they can store more information, have a larger information capacity, and have the characteristics of high fault tolerance and high density. Information can be read even when it is partially damaged or blocked.

How information is stored in a QR code

The storage method of QR code is to represent different information by arranging black and white pixels on a two-dimensional plane. Specifically, the QR code is composed of multiple small squares (also called modules), each of which can be white or black, representing binary 0 or 1. These small squares are arranged according to specific rules to form a matrix-like pattern - a two-dimensional pattern.

In a QR code, information is encoded as a series of data. During the encoding process, a special encoding algorithm is used to convert the information into binary data and map it to the modules of the QR code. When the scanning device reads the QR code through an optical sensor, it parses the arrangement and color information of the modules and converts it into corresponding binary data. Then, according to a specific decoding algorithm, the binary data is converted back to the original information content.

In general, the way QR codes store information is to represent different binary data through the arrangement and color of modules, and then improve the accuracy and fault tolerance of recognition through coding and redundant information. When a scanning device reads a QR code, it analyzes the arrangement and color of the modules to restore the coded information, thereby reading the data stored in it.

Tens of billions of QR codes are used around the world every day

Nowadays, the usage of QR codes is huge. According to incomplete statistics, the global usage of QR codes is as high as more than 10 billion per day. So, will QR codes be used up?

Theoretically, a QR code will be used up one day. The size of a QR code is fixed, and the number of black and white squares that can be arranged and combined in a fixed area is limited. When the stored data exceeds the capacity limit, it will be used up. However, in actual applications, the capacity of a QR code is usually very large, far exceeding the amount of data we usually need to store.

Take the WeChat payment code that we usually use as an example. The size is 25×25. There are 625 small squares in this QR code matrix. Excluding some squares for positioning, error correction and other functions, there are 478 squares left. Each square has two colors, black and white, which can form 2^478 different QR codes. Assuming that 10 billion payment QR codes are used every day, 365 billion are used a year, which means that it will take 2.1×41^131 years to use up all the payment QR codes. The universe has been around for only 13.7 billion years, or 1.37×10^10 years, so there is no need to worry about the QR codes being used up.

(The author is a member of Shen Jingfang's famous teacher studio at Huazhong Agricultural University)