Reborn Hacker

There are not many people in the bookstore, except for an uncle standing at the counter, there are only 3 people standing in the bookstore reading books, He Ran is one of them.

He Ran was very relieved to find two foreign hacking tutorials in the bookstore, which are relatively rare in country Z where the Internet has just started, and these two tutorials still have a certain amount of gold.Before rebirth, He Ran didn’t start learning hacking skills until high school, and his English wasn’t very good at that time, so he mostly chose tutorials translated into Chinese, but he didn’t see many of the original tutorials that were passed on in the early days. .

He Ran leaned against the wall to read a book, occasionally nodded when he saw a point of view he agreed with, and frowned when he saw a theory that was proven wrong by later generations.And not far away from Heran, there was a college student who was also reading a hacking tutorial.In contrast, this college student's expression is mostly suddenly enlightened.

This college student had a hard time reading it. It may be that the professional terms in the English hacking tutorial are still difficult to understand. He happened to see a word that he couldn't understand. He Ran while reading a book.When He Ran looked up, he found that he and he were reading the same book. In this age, He Ran was surprised.

"MD5..." He muttered to himself while flipping through the computer terminology dictionary.

He Ran rolled his eyes and said, "I can't find it in the dictionary of computer terms."

Li Fei (a student of H University of Technology, during the winter vacation) flicked through the dictionary, looked up at He Ran, and said, "You know?"

"MD5, full name MessageDigestAlgorithm5, is a one-way hash algorithm developed by RSA Data Security Company. It is widely used and can be used to encrypt data blocks of different lengths into a 128-bit value. MD5 uses hash functions, the irreversible encryption algorithms widely used in computer networks include the MD5 algorithm invented by RSA and the secure hash algorithm SHA suggested by the National Institute of Technology and Standards." He Ran answered confidently, and only when dealing with computers, He can show such a dazzling side when dealing with hacker technology.

Seeing He Ran's confident look, Li Fei felt a little unbelievable, but he couldn't believe it from what he heard.He hesitated and asked, "How old are you this year?"

He Ran was stunned, it was difficult to handle, a 15-year-old hacker would scare people to death if he said it.

"I'm 15 years old. I like computer things. I have seen the explanation and description of MD5 in some book before." He Ran turned his head to look at the wall clock on the wall, pretending to be in a hurry, "It's getting late Goodbye." Then, put down the book and hurried out of the bookstore.

He Ran who walked out the door thought, fortunately it was just an explanation of nouns, I should not act like a hacker.He Ran tilted his head, and felt that it was completely unnecessary. Even if he was a student of the computer department, few people knew about hacking. Besides, the other party also had a hacking tutorial in his hand.Forget it, anyway, I won't meet again in the future.

On the other hand, Li Fei was staring at the book in his hand, struggling: 15 years old?I am nearly 10 years old, how can I know more than me.Could it be that there is a professor of computer science in the family, or is he a computer genius?Only when he came back to his senses did he realize that the boy who answered him had disappeared.

"Uh... Where's the person?"

He Ran was in a good mood on his way home.

"Why! How!"

Hearing his name suddenly, He Ran turned his head and was hooked around the neck by a strong arm.

"He Ran, go to my house and play a few games of Contra." Qian Bin was dragging him to go in the opposite direction, "You don't know, Xu Tao's skills are too bad, teaming up with him is simply looking for death."

And Xu Tao, who was said to be unskilled, was standing 10 meters behind the two of them.

"I'm so sorry, my skills are terrible." Xu Tao pushed his glasses.

This action sincerely made He Ran, who was impacted by Internet culture ten years later, feel a chill.He Ran is not short-sighted yet, but He Ran feels that even if he becomes short-sighted later and wears glasses, he is incomparable with Xu Tao's temperament now.Speaking of which, Xu Tao is indeed the smartest of the four.As for He Ran's later appearance of shrewdness, he himself knew very well that it was an illusion.

"Oh, don't worry about it. Besides, you really don't play well." Qian Bin is not affected at all, probably because he hangs out with Xu Tao a lot and sees him pushing his glasses too much, so he can ignore the chill.

"Speaking of playing games, Qian Bin, when will you return me the little bully?" He Ran quickly remembered the point, "I'm going to use it soon."

"No way, why are you so unfriendly, I only borrowed it for a few days to play."

"If half a semester is called a few days..." Xu Tao complained.Of course, the current Xu Tao doesn't know the meaning of complaining at all.

Qian Bin froze: "Can't I borrow it for a few more days?"

"I'm really useful. You also know that it was impossible for my family to buy a computer before I was in high school. If I want to be familiar with computer keyboards and certain operations, I must rely on Xiaobawang. Computers will definitely be of great use in the future. If If I bought a computer but I can’t even type and don’t know how to use it, then wouldn’t I be a fool.”

Xu Tao once again looked at He Ran who emphasized that computers will be of great use in the future.He even had a little vague idea in his mind.On this point, Xu Tao deserves to be the smartest of the four.Before He Ran's rebirth, Xu Tao was a relatively successful businessman, which has something to do with his shrewdness.

"By the way, when will you teach us how to use computers?" Xu Tao asked.

"If you want to learn, first go to the bookstore and look at the basic computer operation tutorials. You must learn the basic operations at the beginning. The basic things are relatively simple. It doesn't matter if you don't have a computer to practice now. It will definitely be easy to use when you use a computer. .If you want to deal with files, or do programming, you need a real computer. By the way, typing can also be practiced earlier.”

Qian Bin was not happy: "If you want to learn, of course you should learn the most advanced ones, who should learn the elementary ones."

"It's not elementary, it's the basics. You want to run before you even know how to walk. It won't kill you. By the way, you must practice typing with 10 fingers at the same time. One-finger meditation is really ugly." He Ran said. .

"I agree with what He Ran said." Xu Tao seconded.

Qian Bin looked at He Ran, then at Xu Tao: "Wait, wait until I learn it, and see what you ask me to teach you."

Qian Bin didn't realize that he was motivated to study computer.

He Ran doesn't have to make all his friends become hackers, but computers are really important in the future, at least his friends must master a skill in eating before the average person.As for how far they have reached, it all depends on them. If they want to learn, he is definitely willing to teach.If you don't want to learn, you must at least know the basics of computer operations, and you must be proficient in office processing software and the like.

He Ran played a few games like Contra at Qian Bin's house. Although he hadn't played it for many years, He Ran still played well.Later, when he went home, he took Xiaobawang home, and Qian Bin stared at him eagerly for a long time.

He Ran quickly realized: "If you want to play games, you can come to my house and play."

With He Ran's promise, Qian Bin finally let He Ran go away with little bully in his arms.

After returning home, He Ran couldn't wait to connect Xiaobawang to the TV.

Looking at the DOS interface, He Ran felt extremely cordial.

He Ran quickly started the DOS operation, and N lines of code jumped out on the TV after a while.Xiaobawang is not a computer after all, many programs cannot be run, and the programs written cannot be stored.However, considering Heran's current family situation, it is obviously impossible to buy a computer that meets his wishes, and he does not want to casually buy a low-configuration home computer, so he has to continue to use his Xiaobawang .

"There are still 4 months before the Internet connection. The waiting time is really hard." He Ran counted the days when country Z would be connected to the Internet, but forgot the fact that he didn't have a computer to connect to the Internet at all.When he remembered it, he looked up to the sky and sighed, even if he was connected to the Internet, there was basically nothing wrong with him.

In 95, it was difficult to connect to the Internet. He Ran thought with emotion, in the first year of high school, I could only get a low-configuration computer. My high-configuration computer, where are you?

After He Ran went to Lu Kai's physics cram school twice, he was informed that the cram school would not be held, and that Lu Kai would move to a big city.Instead, Lu Jiahao left a phone call for He Ran and told him that he could ask him for help.It was actually for the computer that someone helped fix it for free.And He Ran's mother didn't help He Ran enroll in a new cram school after knowing that the cram school could not be completed, but only asked He Ran to study hard at home.

He Ran will spend the rest of the winter vacation with Xiaobawang.After finishing all the homework for the winter vacation, compared to his three friends, He Ran basically has no learning tasks.Sometimes Qian Bin, Xu Tao and Fu Chengliang would come over to play together, and sometimes he would go to Fu Chengliang's house to popularize the basic computer knowledge for the three of them, and occasionally he would go to the bookstore to see if there were any hacking tutorials. But I never met the college student I met last time.Of course, He Ran also emphasized to his friends the importance of being admitted to a good high school and a good university. After all, academic qualifications still play a very important role in finding a job in modern society.He Ran, who has experience in the senior high school entrance examination, also wants to help his friends. During the winter vacation, he sorted out many sets of key and difficult test papers for the senior high school entrance examination. Since they were handwritten, He Ran's handwriting with a personal style since high school surprised the three of them. .He Ran had no choice but to use the test papers and handwriting practice in the first half of the third year of junior high school as an excuse to pass.

Overall, He Ran's entire winter vacation was quite fulfilling.

Before you know it, the winter vacation is coming to an end, and the busy life in the third year of junior high school is about to begin.

The author has something to say: It is really painful to search for information...

Small information: see baike.baidu.com/view/7636.htm for details. Abstract: MD5 algorithm

1991年，Rivest开发出技术上更为趋近成熟的md5算法。它在MD4的基础上增加了"安全-带子"（safety-belts）的概念。虽然MD5比MD4稍微慢一些，但却更为安全。这个算法很明显的由四个和MD4设计有少许不同的步骤组成。在MD5算法中，信息-摘要的大小和填充的必要条件与MD4完全相同。Denboer和Bosselaers曾发现MD5算法中的假冲突（pseudo-collisions），但除此之外就没有其他被发现的加密后结果了。

Vanoorschot和Wiener曾经考虑过一个在散列中暴力搜寻冲突的函数（brute-forcehashfunction），而且他们猜测一个被设计专门用来搜索MD5冲突的机器（这台机器在1994年的制造成本大约是100万美元）可以平均每24天就找到一个冲突。但单从1991年到2001年这10年间，竟没有出现替代MD5算法的MD6或被叫做其他什么名字的新算法这一点，我们就可以看出这个瑕疵并没有太多的影响MD5的安全性。上面所有这些都不足以成为MD5的在实际应用中的问题。并且，由于MD5算法的使用不需要支付任何版权费用的，所以在一般的情况下（非绝密应用领域。但即便是应用在绝密领域内，MD5也不失为一种非常优秀的中间技术），MD5怎么都应该算得上是非常安全的了。

MD5 uses a hash function, and the irreversible encryption algorithms widely used in computer networks include the MD5 algorithm invented by RSA and the secure hash algorithm SHA suggested by the National Institute of Standards and Technology.