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What to buy for football: a professional guide helps you find the best choice.

Football is the most popular sport in the world, and it has a broad mass base, whether as a leisure or professional competition. If you are a football fan, or you just want to play football in your spare time, it is very important to choose a good football. This article will provide you with some professional guides to help you find the best football.

1. Material: The material of football is mainly divided into leather and synthetic materials. Leather football is usually more durable and feels better, but the price is also higher. Synthetic football is cheaper, but it may not be as durable as leather football. You need to choose the right material according to your budget and frequency of use.

2. Size: The size of a football is usually marked by its diameter. Generally speaking, the diameter of a standard match ball is 21.5 cm. However, for beginners, it may be better to choose a bigger football because it can help them control the ball better. If you are an adult or a teenager, you can choose a smaller football.

3. Weight: The weight of football is also very important, because it will affect your performance in the game. Generally speaking, the standard football weighs about 410 grams. If you often train for a long time, then you may need to choose a heavier football.

4. Brand: There are many well-known football brands in the market, such as Adidas, Nike and Puma. These brands of football have certain quality assurance, but also have their own characteristics in design. You can choose a brand according to your personal preference and budget.

5. Price: The price of football varies greatly, ranging from tens of yuan to hundreds of yuan. Although the higher the price, the better the quality of football, but you don’t need to spend a lot of money to buy a good football. Generally speaking, 100-200 yuan football is enough to meet the needs of most people.

6. Test: Before you buy a football, you’d better try it yourself. You can try a few kicks on different courts to see how the ball feels. In addition, you can also ask your friends to try it and listen to their feedback.

Generally speaking, it is not difficult to choose a good football. The key is to choose according to your own needs and budget. I hope the above suggestions can help you.

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A domestic football match was scolded by a hot search. What happened?

Source: China News Network

On the 8th, a topic entry named # Match-fixing in the Final of Guangdong National Games # occupied a high position in Weibo’s hot search for a long time. As of press time, the reading volume of this topic exceeded 140 million, and nearly 9,000 people participated in the discussion.

From the perspective of competitive sports, this game is not a high-level event. If there are no special circumstances, it will not attract so much public attention to a great extent.

However, looking at the comment area, everyone has a hot discussion.

It’s the darkest hour of football in China, except for the 15-year-old boys.This is a sentence left by a netizen in the topic discussion area.

In the eyes of professional football media, there are also problems in this game. “After watching the replay of the game, there is indeed a suspicion of match-fixing, which supports a thorough investigation."

Everyone’s response is filled with the most emotions, which are helplessness and anger. In other words, today, football in China is still at a low ebb, and this game has poked a lot of people who care about football in China.

Let’s get to know the situation of this game first.

The match was held on August 7th, 2022. It was the men’s B Group A final of the 16th Guangdong Sports Games, and was played between Qingyuan team and Guangzhou team. There was no abnormal situation after the start of the game. In the second half, Qingyuan team took the lead 3-1.

But since then, the Qingyuan team seems to be like a "power outage." Goalkeepers and defenders pass the ball at will in the backcourt and are directly intercepted by opponents; When the Guangzhou team launched the attack, the Qingyuan team defender did not seem to stop the football from entering the goal; According to the camera, several Qingyuan team players started the "walking" mode on the court …

In the end, Guangzhou defeated Qingyuan 5-3 to win the championship.

After the video of this game exploded on social media, Dong Lu, a well-known football media person, used "weird 13 minutes" to describe what happened on the field.

While the outside world is discussing the game,The Chinese Football Association officially announced the launch of an investigation into the game.. The announcement said that in this competition, the performance of athletes from both sides on the field was widely questioned by public opinion, which aroused the concern of all sectors of society. China Football Association attaches great importance to this and starts the investigation procedure, and will form an investigation team with the participation of the Competition Department, the Discipline Inspection Department and other departments, and will go to Guangzhou for investigation on August 8.

It is not what China football wants to cause a heated discussion in such a way.

This year’s poor World Cup preliminaries once again put the national football team into an "infinite loop", and many fans didn’t know how to face the China football that had been in the trough for a while.

In fact, there has been a lot of news about football in China recently.

The Chinese Super League officially resumed the home and away game system. For professional teams and clubs, the home game was opened for a long time, and when familiar spectators entered the stadium again, it brought more positive signals to the team’s operation.

In the East Asia Cup competition that ended at the end of July, the China Men’s Football Team with "U23 National Team" as the main team won the third place.

Although only four teams participated in the East Asia Cup, this ranking did not satisfy the Chinese people. However, the original intention of sending young players out to increase the experience of the competition and taking this opportunity to upgrade is no problem. In the second round, the national football selection team drew with Japan. The game data still shows that there is a big strength gap between the two sides, but with courage and perseverance, the young players can gain confidence and bring some comfort to the depressed football in China.

When facing the pressure and challenges, face the difficulties and use your own efforts to resist the difficulties. Even if you fail to win the game, you will gain confidence. This may be a more realistic idea, and it is also the most needed for today’s China football.

At present, the official has been involved in the investigation of this controversial competition, but the final result has not yet been released. As for whether it is the "fake ball" mentioned by everyone, we still don’t argue.

A few days ago, the first China Youth Football League started. Wang Dengfeng, deputy director of the China Youth Football League Office and director of the Department of Sports, Health and Arts of the Ministry of Education, said, "Whether more and more children can play football is a key issue facing China football at this stage."

As the future of football in China, youth football plays an important role. Please keep it simple and away from the distractions. Only in this way can we help the development of football in China.

Artificial intelligence challenges quantum cryptography

Abstract: Quantum cryptography is a technology that uses the principle of quantum mechanics to realize the secure transmission and encryption of information. It has the advantage of resisting the attacks of traditional computers and quantum computers. However, with the development of artificial intelligence technology, quantum cryptography is also facing new challenges and threats. This paper analyzes the influence and possibility of artificial intelligence technology on quantum cryptography, and discusses the principle and prospect of post-quantum cryptography as a coping strategy.

Step 1 introduce

Information security is one of the important problems facing today’s society, especially in the fields of finance, medical care and military affairs. Information leakage or tampering may cause serious losses and harm. In order to protect information security, the traditional method is to construct encryption algorithm by using difficult problems in mathematics, such as public key encryption algorithm based on large number decomposition or discrete logarithm problem. However, these algorithms are at risk of being cracked or attacked, especially after the emergence of large-scale quantum computers, because of their exponential acceleration advantages, they can effectively solve some difficult problems in classical calculation.

In order to deal with this threat, quantum cryptography came into being. Quantum cryptography is a technology that uses the principle of quantum mechanics to realize the secure transmission and encryption of information. It mainly includes two aspects: one is to encode and transmit information by using single photon or other microscopic particles as carriers; The second is to use Heisenberg uncertainty principle, cloning theorem and other physical laws to ensure information security. The most typical and mature example is Quantum Key Distribution (QKD) technology based on BB84 protocol.

QKD technology can establish a secret key between two remote communication parties (usually called Alice and Bob) that only they know and cannot be obtained or modified by eavesdroppers (usually called Eve). This secret key can be used for one-time encryption (OTP) of other information, thus achieving perfect confidentiality. QKD technology has the following characteristics:

-Safety is based on physical laws rather than mathematical assumptions;

-eavesdroppers can be detected and eliminated;

-Can adapt to any type and length of information;

-Only low-complexity and low-cost equipment is needed;

-Compatible with existing network structures.

Based on the above advantages, QKD technology is considered as an effective means to resist quantum computer attacks, and has been widely studied and applied in laboratories and practical scenes.

However, quantum cryptography is not perfect, and it also faces some challenges and threats. One of the important sources is artificial intelligence (AI) technology. AI technology is a branch of computer science that simulates or surpasses human intelligence. It involves many fields such as machine learning, deep learning, neural network, natural language processing, computer vision and so on. AI technology has made rapid development and breakthrough in recent years, and has produced great influence and value in all walks of life.

The influence and possibility of AI technology on quantum cryptography are as follows:

-AI technology can be used to improve the performance and efficiency of quantum cryptography;

-AI technology can be used to analyze the security and reliability of quantum cryptography;

-AI technology can be used to attack or crack quantum cryptography systems;

-AI technology can be used to construct new quantum cryptography protocols or algorithms.

This paper will elaborate these four aspects in detail, and discuss the principle and prospect of post-quantum cryptography as a coping strategy.

2. AI technology improves the performance of quantum cryptography system.

Although quantum cryptography has perfect confidentiality in theory, there are still many limitations and difficulties in practical operation. For example:

-Single photon signals are easily disturbed or lost due to factors such as fiber loss or spatial attenuation;

-Due to factors such as equipment error or environmental noise, single photon detection is easy to produce error code or false positive;

-Single photon transmission is easily disturbed or manipulated due to channel instability or eavesdropper attacks;

-Because the key generation rate is limited by signal strength, bit error rate, eavesdropping detection rate and other factors, it is difficult for single photon encryption to achieve high efficiency.

These problems lead to a lot of post-processing operations such as error correction, privacy amplification and information renegotiation in the process of quantum key distribution. These operations not only increase the communication time and cost, but also reduce the communication quality and security.

In this respect, AI technology can exert its powerful data processing ability and adaptive learning ability, and help optimize and improve the performance and efficiency of quantum cryptography system. Specifically, AI technology can be applied to the following aspects:

-AI technology can be used to predict and adjust the intensity and polarization of single photon signals to adapt to different channel conditions and requirements;

-AI technology can be used to identify and eliminate the error code and false positive of single photon detection, so as to improve the speed and quality of key generation;

-AI technology can be used to detect and resist the interference and manipulation of single photon transmission to ensure the security and integrity of the key;

-AI technology can be used to optimize and simplify the post-processing operation of single photon encryption to reduce communication time and cost.

In these ways, AI technology can make the quantum cryptography system more stable, efficient, reliable and safe.

3. AI technology to analyze the security of quantum cryptography system

Although the quantum cryptography system guarantees perfect confidentiality in theory based on physical laws, there are still many security risks in actual operation. For example:

-Due to factors such as imperfect equipment or inaccurate model, there may be loopholes or defects in quantum cryptographic protocols or algorithms;

-Due to unreasonable parameter selection or inaccurate estimation, the quantum cryptography system may be over-optimized or over-conservative;

-Due to insufficient experimental data or inappropriate analysis methods, there may be misjudgments or missed judgments in quantum cryptography systems;

-Because eavesdroppers have more powerful computing power or attack means, quantum cryptography system may be at risk of being cracked or attacked.

These problems lead to strict and complex security analysis and evaluation of quantum cryptography system in practical application. These analyses and evaluations not only need a lot of theoretical knowledge and empirical judgment, but also need a lot of computing resources and time.

In this respect, AI technology can play its powerful data mining ability and intelligent reasoning ability, and help analyze and evaluate the security and reliability of quantum cryptography system. Specifically, AI technology can be applied to the following aspects:

-AI technology can be used to find and repair the loopholes or defects of quantum cryptography protocols or algorithms, so as to improve the robustness and adaptability of the system;

-AI technology can be used to optimize and adjust the parameter selection and estimation of quantum cryptography system to achieve the best security performance ratio;

-AI technology can be used to verify and improve the experimental data and analysis methods of quantum cryptography system to improve the accuracy and effectiveness of the system;

-AI technology can be used to predict and prevent the cracking or attack risk of quantum cryptography system to ensure the security and integrity of the system.

In these ways, AI technology can make the quantum cryptography system more credible, controllable, reliable and secure.

4. AI technology attacks or cracks quantum cryptography systems.

Although quantum cryptography system has the advantage of resisting the attacks of traditional computers and quantum computers, it does not mean that it is absolutely safe. In fact, with the progress of science and technology, eavesdroppers may also have more powerful computing power or attack means, thus posing a threat to the quantum cryptography system. For example:

-The eavesdropper may take advantage of factors such as imperfect equipment or inaccurate model to carry out classic attacks such as side channel attack, man-in-the-middle attack and playback attack;

-The eavesdropper may use the single photon signal itself or other relevant information (such as time, frequency, phase, etc.) to carry out quantum attacks such as optical measurement attacks, coherent state attacks, and nonstandard fundamental attacks;

-The eavesdropper may use the interaction or coupling between the single photon signal and the environment (such as scattering, absorption, diffraction, etc.) to carry out physical attacks such as fault injection attack and environmental noise analysis;

Eavesdroppers may use the entanglement or correlation between a single photon signal and other microscopic particles (such as Bell state and GHZ state) to carry out quantum entanglement attacks such as entanglement uncertainty attack, entanglement stealing attack and entanglement amplification attack.

These attacks may lead to the leakage or tampering of the key of quantum cryptography system, thus reducing or destroying the security and integrity of the system.

In this respect, AI technology can exert its powerful computing power and attack ability to help eavesdroppers attack or crack quantum cryptography systems. Specifically, AI technology can be applied to the following aspects:

-AI technology can be used to simulate and analyze the equipment, model, parameters, data and other information of quantum cryptography system, so as to find the loopholes or defects of the system;

-AI technology can be used to design and implement classical attacks, quantum attacks, physical attacks, quantum entanglement attacks and other attacks of quantum cryptography systems;

-AI technology can be used to collect and process single photon signals or other related information of quantum cryptography system to extract or tamper with key information;

-AI technology can be used to forge and cover up post-processing operations such as eavesdropping detection or error correction of quantum cryptography systems to avoid being discovered or confronted.

In these ways, AI technology can make eavesdroppers more hidden, efficient, powerful and dangerous. 5. AI technology to construct a new quantum cryptography protocol or algorithm.

Although there are various protocols or algorithms in quantum cryptography system, it still has great development space and potential. For example:

-Quantum cryptography system can use more physical resources or mechanisms, such as multiphoton signals, high-dimensional space, continuous variables, nonlinear effects, etc., to improve the performance and security of the system;

-Quantum cryptography system can use more mathematical tools or methods, such as coding theory, information theory, complexity theory, random number generation, etc., to improve the robustness and adaptability of the system;

-Quantum cryptography system can make use of more application scenarios or requirements, such as network communication, distributed computing, cloud computing, Internet of Things, etc., to improve the practicability and value of the system;

-Quantum cryptography systems can use more security objectives or standards, such as unconditional security, provable security, post-quantum security, information theory security, etc., to improve the credibility and controllability of the system.

All these aspects need to be innovated and explored to construct new quantum cryptography protocols or algorithms.

In this respect, AI technology can exert its powerful creativity and learning ability, and help to construct new quantum cryptography protocols or algorithms. Specifically, AI technology can be applied to the following aspects:

-AI technology can be used to simulate and optimize the physical resources or mechanisms of quantum cryptography systems to discover new quantum signals or quantum effects;

-AI technology can be used to design and verify mathematical tools or methods of quantum cryptography, so as to discover new coding schemes or information metrics;

-AI technology can be used to adapt to and meet the application scenarios or requirements of quantum cryptography systems to discover new communication modes or computing tasks;

-AI technology can be used to evaluate and improve the security objectives or standards of quantum cryptography systems, so as to discover new security certificates or security guarantees.

In these ways, AI technology can make the quantum cryptography system more diverse, advanced, practical and reliable.

6. Conclusion

This paper discusses the relationship and function between AI technology and quantum cryptography from four aspects. First of all, AI technology can improve the performance and efficiency of quantum cryptography system; Secondly, AI technology can analyze and evaluate the security and reliability of quantum cryptography system. Thirdly, AI technology can attack or crack quantum cryptography systems; Finally, AI technology can construct new quantum cryptography protocols or algorithms. All these aspects show that AI technology has important and extensive application value and development potential in the field of quantum cryptography.

Of course, this paper only gives a preliminary and brief introduction to this subject, and does not involve more details and problems. For example:

-Is there some basic principle or law between AI technology and quantum cryptography?

-Is there any interaction or restriction between AI technology and quantum cryptography?

What are the similarities and differences between AI technology and other types of encryption systems (such as classic, hybrid, post-quantum, etc.)?

These problems are worthy of further study and exploration.