Shulou(Shulou.com)11/24 Report--

Today, let's talk about one thing that is very closely related to our daily life today-we travel, eat, shop, and may use it almost every day. That's right, it's a QR code.

Once upon a time, who would have thought that a small black-and-white code would have such a wide range of uses? who would have thought that this seemingly ordinary black-and-white square was imperceptibly changing our lives?

Scan the code to add friends: expand your social circle anytime, anywhere.

Scan the code to pay: now even the roadside selling fruit uncle in Wechat, Alipay collection, if you still stubbornly use cash to pay, it is really "out".

Itinerary tracking code: since the epidemic, personal one-code pass, as a key electronic voucher for personal travel during the epidemic control period, has laid a solid foundation for epidemic prevention and control, and is an important guarantee for the safety of citizens.

These are only the most common application scenarios of QR codes, including scanning the product electronic manual, membership management, advertising push, and so on.

Do you remember when you started using QR codes? Do you know anything about QR codes? Why do all the QR codes we see have three small return squares? Let's unveil its mystery today.

Now the widely used QR code is QR (Quick Response) code, which first appeared in 1994 and was introduced into China in 2001. It has been rapidly integrated into our lives.

The composition and principle of the two-dimensional code the two-dimensional code is transformed from the bar code. It is most common in the packaging of goods, which is composed of vertical stripes of different thickness in black and white, and the information of the goods is hidden in this bar code.

The cashier can get the product information by scanning the bar code, thus realizing the quick checkout. A bar code is a bar code that carries information in one dimension, and the two-dimensional code, as its name implies, carries information in both horizontal and vertical dimensions, so it changes from a bar to a square. Whether it is a bar code or a QR code, it is essentially an information portal.

A complete QR code is composed of several small black squares and small white squares. First of all, the characters such as numbers, letters and symbols are converted into binary "0" and "1" through certain operation and coding rules. then after a series of optimization algorithms, the QR code is obtained. The small white squares on the QR code represent the binary "0" and the small black squares represent "1".

When the QR code is read, the 01 order on the QR code is read by color contrast, and then the binary is converted into characters that we can recognize through numbers, bytes, special characters, mixed coding, Chinese character coding and so on.

The generation of QR codes follows binary coding, and their arrangement is the embodiment of the information. Its basic functional areas are divided into:

Position detection pattern, position detection pattern separator, location pattern: a large black-and-white square-position detection pattern is distributed in the three corners of the QR code, which, together with the position detection pattern separator and location graph, helps to locate the QR code in the process of formation and reduce the occurrence of misalignment. Whether your phone sweeps horizontally, vertically, or sideways, it knows in which direction the QR code should be read. For each QR code, their position is fixed, but the size and specification will be different.

Format information: indicates the error correction level of the QR code, the higher the level, the stronger the error correction ability. For example, there are 100 codeword data that need to be encoded, and if you want to correct half of them, that is, 50 codewords, the calculation method is as follows. Error correction requires twice as many symbols as the codeword (RS codeword), so the number in this case is 50 x 2mm 100 codewords. Therefore, the total number of codewords is 200, of which 50 are used for error correction, so it is calculated that the error correction rate relative to all codewords is 25%. This ratio is equivalent to the "Q" level in the error correction level of QR codes.

Level L: up to 7% of the code can be modified.

Level M: up to 15% of the code can be modified.

Level Q: up to 25% of the code can be modified.

Level H: up to 30% of the code can be modified.

Correction graphics: when the image is damaged to a certain extent, the decoding software can use it to synchronize the coordinate image of the image module. The number and location of QR code correction graphics of different specifications are different. If the specification is determined, its quantity and location will be determined.

Data and error correction codewords: actually saved QR code information and error correction codewords. This is a fault-tolerant mechanism of the QR code. For example, if less than 30% of the area of a QR code is covered or removed, the QR code scanner can still accurately obtain information from the incomplete QR code.

Version information: that is, the specification of the QR code, the QR code symbol has a matrix of 40 specifications, from 21x21 (version 1) to 177x177 (version 40), each version adds 4 modules vertically and horizontally compared with the previous version. Each version of the QR code has a corresponding maximum number of input characters according to the amount of data, character type and error correction level, which should be selected according to the actual demand. If you increase the amount of data, more symbols are needed, and the QR code will be larger.

When the scanning setting starts to scan the QR code, the area to be identified is quickly extracted according to the position detection pattern, the position detection pattern separator and the location pattern. Sometimes when we scan the QR code with mobile phones or other devices, it is not facing the QR code, or even facing the QR code, it will cause the QR code to tilt, stretch and so on to a certain extent. However, we find that this does not affect the recognition of the QR code, so the correction graphics designed as fixed proportion rectangles can help the device correct the scanned image correctly.

To sum up, the recognition process of our QR code is roughly as follows: turn on the phone or other devices to scan the QR code, scan the QR code, fail to scan, tell you to go back to the previous step and start over. The scan box is displayed to facilitate the user to align the QR code.

Will the QR code be exhausted? Today, almost every country on the planet uses QR codes every day, and more than 10 billion QR codes are used every day, so will QR codes be used up one day? It depends on how many QR codes humans can produce.

There are many kinds of QR codes (QR code is just one of them, other common ones are QR Code, Code 49, Code 16K, etc.), each kind of QR code can carry a lot of information.

For the same kind of QR code, each version can carry a lot of information due to the differences between different versions.

The coding mode of QR code is different, and the information it contains is also different.

The QR code can be reused, for example, the same QR code can be used to jump different links, and the same QR code allows people to scan at different times and places to see different content.

The minimum QR code we currently use as an example, the specification is 21 × 21, which contains 21 × 21 arrangable points, all of which can represent 1 or 0. Therefore, it is calculated according to the method of permutation and combination, which is the 441 power of 2, and if it is expanded, it is 5.678 × 10 ^ 132, which is already astronomical. Just one version of a coded QR code can store so much information that we don't have to worry about running out of QR codes at the rate that humans use up 10 billion QR codes a day.

The security problem of QR code "living on the code" brings convenience to us, at the same time, the security problem also follows. Because the QR code generator is easily obtained from the Internet and published without restrictions, it is easy to be used by some lawbreakers to carry out network fraud.

Share a real case: when Mr. Li was shopping on Taobao, he took a fancy to an LCD TV in an online store, which was nearly a thousand yuan cheaper than the one on the market. The shopkeeper, Tianma Taoyuan, claimed that he could get "private goods" at a low price, and Mr. Li accepted the shopkeeper's request for him to pay by scanning the QR code. Mr. Li scanned the QR code sent by the shopkeeper through his mobile phone, entered a payment interface, entered the bank account number and password, and clicked on the payment, but found that the payment failed. The shopkeeper told him that there might be a malfunction in the system and asked him to rescan. Mr. Li scanned seven times, all of which ended in failure and had no choice but to cancel the deal. But then I found that my bank card was deducted more than 17000 yuan, and then I realized that I had been cheated. Therefore, it is necessary to establish a sense of prevention, improve the understanding of QR codes, and learn to use QR codes correctly.

A liar is cunning, but he never changes his clothes. We should be careful when we use it every day.

Here are some common traps of QR codes, which you should be more careful about:

QR code fraud

Fishing QR code

Receive the prize free of charge

Wait

So how to enhance the security of QR code and reduce the risk of code scanning?

To ensure the security of QR codes, efforts need to be made in the following four areas:

When enterprises provide QR codes to the outside world, they should ensure the security of QR codes.

When we scan the QR code, one is to use the terminal with the security authentication function, and the other is to have security awareness and not to scan the QR code from unknown sources.

National legislation protects acts related to the payment of QR codes.

With the development of technology, there are "Chinese letter codes" that are more secure, suitable for Chinese characters and contain more information.

At present, the QR code is mainly suitable for mobile payment, so our National payment Clearing Association has issued the Bar Code payment Business Specification to various payment institutions, which clearly points out the security standards that payment institutions need to abide by in carrying out bar code business. this is also to ensure that we are more secure when using QR codes on a daily basis. And we should also establish a sense of prevention, improve the understanding of the QR code, correctly use the QR code, pay attention to protect the payment code when shopping, and let the QR code bring more convenience to our lives.

With the development of science and technology in our country, our country is also developing our own "QR code"-Hanxin code. On July 28, 2021, the Hanxin code ISO international standard project was unanimously approved. On August 27, Chinese Code ISO International Standard ISO / IEC 20830 "Information Technology automatic Identification and data acquisition Technology Chinese Code Bar Code symbol Specification" (Information technology-Automatic identification and data capture techniques-Han Xin Code bar code symbology specification) was officially published. This is our national independent research and development, and compared with other international QR codes, Hanxin code is more suitable for the representation of Chinese character information, and can accommodate more information.

Well, today's useful knowledge has increased again:

The composition area and working principle of QR Code

The QR code is inexhaustible.

Common security problems of QR code

How to scan the QR code safely.

This article comes from the official account of Wechat: ZTE documents (ID:ztedoc)

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.