The following is the network security experience I compiled for you. You are welcome to read it. For more related content, please pay attention to the experience column. Network security experience

In the 21st century, the Internet has become a part of people's daily life, and many people can no longer live without the Internet. With the Internet, people can live without worrying about food and clothing without leaving home. I just saw the news on TV a few days ago that online shopping is booming at the end of the year and express delivery companies are also "Spring Festival". In the past, people had to ask someone for help when looking for something, but now people look for help from the Internet. I remember one time I didn’t know where the key was, so I searched on Baidu to find out where the key was lost. As a result, I actually found it according to the solution suggested by netizens.

With the explosive development of the Internet, the network environment is becoming increasingly complex and open. At the same time, various security vulnerabilities are also exposed, malicious threats and attacks are increasing day by day, and security incidents are increasing day by day, which also makes everyone who is exposed to the Internet vulnerable. Everyone is threatened to varying degrees. Here, I would like to talk about my experience on the various network security issues I encounter in my life and work:

1. It is important to have network security awareness

When it comes to network security, what makes us helpless is that many people think that this is a matter for computer network professionals. In fact, everyone should be aware of network security, which is especially important for personnel in confidential units. I watched the TV series "Secret War" some time ago, and most of the ways of leaking secrets revealed were caused by the weak security awareness of relevant personnel: the unit requires that confidential work must be completed in the office, or someone takes it home privately to work overtime, causing leaks; important departments require outsiders to No entry is allowed, but some people bring in idle personnel, causing leaks; private network computers are not allowed to connect to the Internet, and some people play games on external networks, causing leaks; even secret personnel accidentally make friends and fall in love with spies, causing leaks. Leak. Although this is just a TV series, it is also a warning to confidential units. While watching this TV series, I was thinking that this should be used as a safety education film for the security department.

Not only for confidential units, but also for individuals, network security awareness is particularly important. There are endless camera leaks on the Internet, and this and that are all caused by personal security awareness. As the teacher said? What you see may not be true!?.

I have some software and systems on my computer that I usually make. Although they are not important, they are all made by myself, so I have always been careful when using the computer for fear of Trojans and viruses. For example, the small bar of "360 Traffic Monitor" is always in the lower right corner of my "desktop". As long as there is upload traffic, I must check to see what process is uploading.

2. Equipment security? Many technologies are beyond our imagination

Network equipment is the hardware foundation for network operation, and equipment security is a completely indispensable part of the network.

I have heard of electrical leaks before, but never seen one. Recently, a colleague at work brought two power cats (power line Ethernet signal transmission adapter). One was plugged into the power supply with a network cable, and the other was One can connect to the power supply within 30 meters and connect the network cable to the computer through the interface to access the Internet. This reminds me that as long as someone connects a confidential network line to a power line, the secret can be easily leaked. Of course, the national security department must have relevant preventive measures.

Search in the search engine for example: intitle:"Live View/-AXIS 206W", etc., you can search for web cameras. In the TV series "Secret War", the surveillance system of a secret department is connected With the advent of the Internet, spies use surveillance systems to steal staff screen information and keystroke information. By installing a mobile network-based transmitter on a copy machine in a confidential government office, all scanned confidential documents can be received on another receiver.

In 1985, at an international computer security conference held in France, the young Dutchman Van Eyck disclosed his technology for stealing computer information in front of representatives from various countries. He modified an ordinary TV set with components worth only a few hundred dollars, and then installed it in a car. In this way, he received the electromagnetic wave information of the computer placed on the 8th floor from the street below, and displayed the computer's electromagnetic wave information. The image displayed on the screen.

His demonstration gave a huge shock to the representatives from various countries participating in the meeting.

I first learned about electromagnetic leaks when I was developing software for a certain department in the army in 2004. Jammers were installed in many places in the army to prevent electromagnetic leaks.

Hard drive data does not exist even if it is deleted. It can be recovered using recovery software such as EasyRecovery. It seems that complete safety can only be guaranteed by melting the confidential hard drive in a steel-making furnace.

3. Beware of Trojans

The first time I learned about Trojans was when I was in college. At that time, I saw a screen sending software called "Big Eyes" on the Internet. I was curious and tried to use it. The computers in the computer room of the university only have commonly used software installed, and other software such as QQ are stored on the server. You install it yourself when you use it. If the student computer has a protection card, it will be restored after restarting, and it must be installed again.

So I put the "big-eyed" client on the server and gave it a very attractive name. As a result, many students’ screens were monitored by us. Some students laughed and said, "Isn't it just a Trojan horse!" After some inquiries, I found out that there is a program called "Trojan horse" that uses the same method to steal privacy. Later, I also made a fake QQ program to steal other people's QQ, but all the stolen money was given to others. Who knew that 7 or 8-digit QQ numbers could be so popular now.

In the past, computers were protected against viruses such as CIH and worms. Nowadays, more protection is used against Trojan viruses, mainly because personal computers can steal passwords such as Alipay, QQ accounts, and online banking. When you open unsafe web pages, when others send you malicious emails, when you install unsafe software, when you use a USB flash drive, you may be infected with Trojan viruses.

Some time ago, during the dispute between 360 and QQ, there were many unsafe software in our computers, which may leak our privacy.

4. Web page security

In my unit, I am responsible for the website maintenance of several departments, mainly web page production. When I first started programming, I never thought that I could be attacked. Later, the websites I built were often attacked, and then I learned about attack methods such as SQL injection and Ewebeditor vulnerabilities, so I will pay attention to the security of these aspects when programming. For example, my background database is usually ?x.asp#xxxxxx.mdb?. Prevent the database from being downloaded.

I remember once again writing a message board program for a certain department. As a result, within a day of release, there were more than 3,000 malicious messages, all in English, which was quite a headache. In the end, the verification code and user verification did not work. It was not until I used the code to detect the source of the message that the web page code was used. It turns out that they were attacked with tools.

5. Develop good Internet habits

Network security involves everyone who uses the Internet. For individuals, to ensure their own safety online, everyone must develop good Internet habits. I think it should include the following points:

1) Firewall and anti-virus software should be installed on the computer and should be upgraded in time. If the computer is connected to the Internet, it should be set to automatically upgrade. And develop a habit of regular computer security scans;

2) Update windows patches in a timely manner;

3) While ensuring system security, make GHOST backups to prevent encountering stubborn viruses The system can be restored in time;

4) Do not click and execute websites and programs sent by netizens using QQ and other websites easily;

5) Do not browse unsafe web pages; < /p>

6) Share files must be closed in time. In the unit, you often see things shared by others on the workgroup computer;

7) No Do not browse familiar emails;

8) Open the U disk after anti-virus;

9) It is best not to log in to your bank account, Alipay, QQ, etc. on other people's computers; For each of us, improving network security awareness and learning network security knowledge are basic requirements for us in the Internet age. Learning experience of network security and cryptography

This semester I took the course of network information security. Since taking the first class, my concept has been completely changed.

The teacher is not just a mechanical reader, or a reader who can only read ppt, but a scholar who is really imparting his knowledge. The teacher's language is vivid and humorous, which gives people great encouragement to continue listening. In class, I also learned a lot about cryptography.

Among various subject fields, only cryptography is unique. It is composed of two sub-disciplines that are opposed to each other, interdependent, but also complementary and mutually reinforcing. These two subdisciplines, one is called cryptography and the other is called cryptanalysis.

The word "password" has an unfathomable and mysterious color to most people. The reason is that its theories and techniques are strictly controlled and controlled by national security (secrecy) agencies related to military, political, and diplomatic matters and are not allowed to be leaked.

The word Cryptology comes from the Greek words "krypto's" and "logos", which means "hidden" and "message". It is the science that studies the security and confidentiality of information systems. The purpose is for two people to communicate over an unsecured channel without the decipherers understanding the content of their communications.

From thousands of years ago to 1949, cryptography had not become a true science, but an art. Cryptography experts often design ciphers based on their own intuition and beliefs, and the analysis of ciphers is mostly based on the intuition and experience of cryptanalysts (i.e., cryptologists). In 1949, American mathematician and founder of information theory Shannon Claude Elwood published the article "Information Theory of Secrecy Systems", which marked the beginning of the cryptography stage. At the same time, the information theory marked by this article established a theoretical foundation for symmetric key cryptography systems, and cryptography has become a science since then.

Due to the need for confidentiality, people basically could not see the literature and information about cryptography at this time, and ordinary people did not have access to passwords. In 1967, Kahn published a novel called "The Codebreaker", which made people aware of cryptography. In the early 1970s, IBM published several technical reports on cryptography, making more people aware of the existence of cryptography.

However, the emergence of scientific theories has not made cryptography lose its artistic side. Today, cryptography is still an artistic science. In 1976, Diffie and Hellman published the article "New Directions in Cryptography". They proved for the first time the possibility of confidential communication without the need to transmit keys between the sender and the receiver, thus creating a new era of public key cryptography. This article has also become a symbol that distinguishes classical ciphers from modern ciphers.

In 1977, the U.S. Data Encryption Standard (DES) was announced. These two events led to unprecedented research in cryptography. From this time on, research on the civilian aspects of cryptography began. Only then did cryptography begin to give full play to its commercial and social value, and only then did people begin to have access to cryptography. This transformation has also led to the unprecedented development of cryptography.

The earliest encryption technology is Caesar cipher. The secret golden wheel means that the encryption and decryption hardware equipment can be used publicly and can be mass-produced to reduce the production and purchase costs of hardware encryption and decryption equipment. Decryption and encryption technologies have always existed, restraining and advancing each other. Intricate encryption and decryption algorithms are constantly evolving to surpass human execution capabilities. The articles Kerckhoffs Principle, Shannon's Perfect Security, DES Algorithm, and Rijndael Algorithm are just like milestones in cryptography, standing on the path of continuous exploration by cryptographers, as a kind of leap, as a symbol.

The above are some common sense issues about cryptography that I learned in this course, and then I will introduce the parts that interest me.

In this course, I am most interested in public key cryptography. In fact, the core foundation of public key cryptography is the positive and negative asymmetry of certain problems in the field of mathematics, such as the integer factorization problem (RSA), the discrete logarithm problem (DL) and the elliptic curve problem (ECC), and none of these problems are Exceptions are inextricably linked to number theory.

The great mathematician Gauss once said, "Mathematics is the queen of science, and number theory is the crown of mathematics." However, unfortunately, in our country's education system, there is almost no introduction to number theory in either primary education or higher education. , the only one covered is the mathematics competition in middle and high schools, but this coverage is definitely extremely limited.

This chapter does not give a complete introduction to number theory, but only explains the knowledge related to the content in the book, including Euclid's theorem and extended Euclid's theorem, Euler's function and Fermat's Little Theorem and Euler's Theorem, among which Euclid's theorem has a more detailed derivation and calculation, the latter two only give conclusions and usage methods. However, considering that the content of these parts is relatively independent, as long as we have a solid understanding of basic knowledge such as prime numbers, composite numbers, and decomposition of prime factors, it should not be difficult to read.

As for the Euler function, Fermat’s little theorem and Euler’s theorem, the proof method is not difficult, and we can also find the relevant processes on the Internet; but its application is quite important, especially the cost-effectiveness. Horse's Little Theorem is the basis of the Miller-Rabbin prime number test. I think students who like mathematics will definitely like this course. This course involves a lot of mathematical knowledge, including number theory, advanced algebra, analytic geometry, group theory and many other fields.

In addition, the various algorithms taught by teachers in the classroom (such as Diffie and Hellman's classic algorithms) have influenced today, contributing to the formation of various emerging algorithms and being cited many times. The classics are still there, and new developments in cryptography are still going on and are still exciting.

I highly recommend