Qin Chuan didn't take Qi Lanfeng's warning seriously.

How dare he, Qin Chuan, provoke such a woman that even their director didn't want to provoke. Instead, out of sight and out of mind, he sent this woman to Shanghai to do covert work.

What's more, He Meili, a beautiful woman, is still here to monitor him.

Also, according to Qi Lanfeng, He Meili's husband is a captain and staff officer of the Second Division of the Central Army, and he will not have anything to do with this married woman.

However, the news told by Qi Lanfeng made Qin Chuan let go of his uneasy heart.

Originally, Qin Chuan was a little worried. What flaws had been exposed in him? Or maybe their perceptive director felt there was something wrong with his words and deeds?

But now it seems that he was overly worried about all this. There must be a reason to send He Meili here, even if the reason is far-fetched, it's okay, and secretly monitor and observe Qi Lanfeng, Wang Jiali, and Qin.

Sichuan, this reason is completely sufficient.

As for Director Dai asking this beautiful woman to focus on observing him, it should be because he, a newcomer, has almost completely mastered the core secrets of this latent mission. This is a routine arrangement for their cautious and rigorous director.

Until he has made more outstanding achievements, his director will never be completely relieved.

After feeling relaxed, Qin Chuan said to Wang Jiali, "Old Wang, since the navy people have arrived, our deciphering team must hurry up. I think we will start training the deciphering team after lunch."
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Wang Jiali had long been eager to train the deciphering team, but Qin Chuan was a little lazy. Now that Qin Chuan took the initiative, Wang Jiali was naturally overjoyed.

In the afternoon, in the office of the deciphering team, Qin Chuan was conducting preliminary training for the members of the deciphering team. Even Wang Jiali was sitting on the sofa consciously, holding a notebook to take notes.

"I won't go into detail about how to compile a password. Everyone knows some methods of compiling a password. Even most of us here may be able to compile a pretty good password. But everyone knows that it is relatively easy to compile a password, but it requires cracking the password.

, it will be very difficult, many people will feel clueless and don’t know where to start.

Next, I will explain the ideas and methods of deciphering passwords, as well as the general logic of password compilation.

Although code deciphering is very complicated, more than 600 years ago, the Persian Qalqashandi first explained the method of using language features and letter frequency to decipher codes. In 1863, the Virginian Table was used.

', and during the First World War, some countries also established code-breaking institutions one after another. Code-breaking methods such as secret tables, secret books and limited multi-table substitution have become very mature.

However, with the advancement of deciphering methods, the methods of cipher compilation in various countries have become more complicated. Now it is very difficult to decipher the ciphers.

Especially now, trying to decipher a set of codes often requires the help of a specialized tabulating machine."

Qin Chuan smiled bitterly and shook his head and said, "Unfortunately, we don't have this kind of tabulating machine yet."

Seeing everyone's disappointed expressions, Qin Chuan continued, "The methods of deciphering codes such as secret tables, secret codes, and limited multi-table substitution have now become mature.

For example, during World War I, the United Kingdom successfully deciphered the "German Minister's Telegram in Mexico" and forwarded it to the United States, thus prompting the United States to join the war.

Up to now, code-breaking technology has made great progress compared to World War I. I found through foreign books and magazines that mathematical analysis methods and tabulating machines, special-purpose machines and other deciphering equipment have been widely used in foreign countries, and they can basically decipher multi-table substitution codes.

Machine password."

Qin Chuan's mouth felt a little dry as he spoke. He picked up the beer glass on the coffee table and took a sip of beer. Qin Chuan now felt that he had some alcohol dependence. He didn't know whether it was because of the time travel, or because of Qin Chuan, or maybe

It's because of his useless system. Anyway, except for drinking light tea in the morning, he prefers beer at other times.

"Modern code-breaking technical methods began at the beginning of this century. Some organizations under the Kuomintang Military Commission also established code-breaking institutions and began to try code-breaking, but the results were lackluster."

Qin Chuan took another sip of beer from the glass, put down the glass and said, "What I just talked about was the development of code-breaking technology. Now I will tell you about the methods of deciphering.

Telecommunications cryptography is a combination of certain plain information such as text and data, an encryption system and a key. The three are interdependent and can be deciphered through analysis, reasoning and verification.

Password deciphering methods are divided into ciphertext attack methods and known plaintext attack methods.

The ciphertext attack method starts with analyzing the ciphertext, judging and verifying the encryption system and key, and then deciphering the plaintext.

The known plaintext attack method uses a certain number of known correspondences between ciphertext and plaintext to analyze and verify the encryption system and key, and then decipher other plaintexts.

To decipher codes of different strengths, the requirements for deciphering conditions are also different, and the degree of difficulty is also very different. From foreign magazines and books, we can find that the mathematical deciphering methods currently used in foreign countries mainly include 'probability theory', 'combination theory'

Mathematics', 'Logical Mathematics', 'Mobius Function' and other mathematical tools to decipher codes...

Code deciphering requires codebreakers to have a solid theoretical foundation in coding and deciphering, rich practical experience, extensive knowledge of related disciplines, rigorous logical reasoning abilities and a tenacious work spirit.

Also, since we now have an opportunity, we will soon use the known plaintext attack method to decipher, so we will use this method as a breakthrough in the near future. Everyone must become familiar with this method as soon as possible in the near future. After everyone is familiar with it,

We will then carry out the ciphertext attack method for decryption, and ultimately need to use both methods at the same time, so the effect will be better."

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Qin Chuan spent an afternoon telling everyone about the methods of deciphering codes. Although Liu Jie and Zheng Yusen have never learned the Möbius function, the knowledge of this function is not complicated. They will definitely not be able to master it.

Question.

In fact, as Qin Chuan mentioned above, Europe, the United States, at least Britain and Germany should have used these mathematical methods to decipher, but using these methods will bring a lot of complicated calculations, especially when encountering overly complex encryption methods.

It often takes hundreds or even thousands of people several months to complete.

In 1949, American Shannon used the two existing mathematical and physical theories of redundancy and entropy to develop a more efficient "unique decoding quantity formula". In this era, it is definitely a powerful decoding tool.

This is naturally Qin Chuan’s secret.

The reason why Qin Chuan did not teach this decoding weapon to his deciphering team was based on two considerations. First, Shanghai would be an occupied area in the future. Once these people were arrested, it would be easy for the Japanese to obtain this "sharp weapon"; second,

He is also very worried that the two sides will use it in a civil war in the future, which will significantly change the course of history.

Therefore, Qin Chuan decided that this "sharp weapon" could only be kept in his own hands for the time being.

At the end of the afternoon training, Wang Jiali, who was excited and flushed, took the lead in applauding.

Wang Jiali stood up and walked to Qin Chuan. First he patted Qin Chuan's arm affectionately, then turned around and said to the deciphering team in a serious tone.

"Everyone has recorded what Deputy Team Leader Qin said. I need to emphasize that today's records of all personnel are absolutely not allowed to be taken out of this room, let alone disclosed to anyone else."

Then, Wang Jiali slowed down and said, "After listening to Deputy Team Leader Qin's training, I am now very confident that we can decipher the Japanese codes. I believe that you will come to Shanghai to carry out this special mission this time.

As long as you follow Deputy Team Leader Qin and do a good job, let’s not talk about money for the time being. I, Wang Jiali, can guarantee that each of you will be promoted."

Wang Jiali looked at Li Mo, the deputy leader of the deciphering team, "Li Mo, you are not young anymore. I estimate that you have been at the rank of second lieutenant for a long time."

Li Mo lowered his head in embarrassment, and Wang Jiali said firmly, "Don't be discouraged, as long as you help Deputy Team Leader Qin do his job well, I will ensure that you are promoted, and it is not only possible to become a lieutenant, but even a captain.
Chapter completed!