After Zhang Weiping left, there were not many people left in the office.
Liu Lu from Nanjing University is still there. The youngest full professor of mathematics in the country is currently squatting in front of the computer and wondering what he is busy with.
Professor Mokomo of Nanyang University, who asked him about the core of the Dirichlet function using the simplified method, is also still here. He is sitting at the table with a frown, calculating something.
He didn't know the remaining two people.
Withdrawing his gaze, Xu Chuan focused his attention on the original cipher text in his hand.
He is not very familiar with cryptography and encryption work, and his knowledge is limited to common sense.
For example, asymmetric encryption system, symmetric encryption system, hash algorithm, MD5 encryption, SHA1 encryption, etc.
He has some knowledge of these common encryption methods, but not much.
However, from a mathematical point of view, there is actually no way to prove that a certain algorithm is "absolutely safe".
Of course, the proof of security in practice is the fact that it has never been cracked, which is still true.
In the past, people thought that the DES encryption system based on the symmetric encryption algorithm was very safe, but with the development of modern computers, an ordinary person's home computer has the computing performance to easily crack it with force.
Nowadays, we believe that encryption algorithms such as AES, RSA, and elliptic curve are safe. After all, there has been no news that these encryptions have been cracked.
But in fact, these encryption methods are not absolutely safe.
For example, if RSA does not perform padding, an attacker can greatly reduce the decryption space by observing the ciphertext of a specific plaintext.
Or if AES encryption is the most primitive mode, then the same ciphertext will correspond to the exact same plaintext.
In addition, some machines are not random enough when generating passwords, so the keys that should be randomly distributed are actually exactly the same.
These are all flaws.
Xu Chuan didn't know much about encryption methods, and these were not things he needed to care about.
In this building, the most elite cryptography experts in District 9 are gathered.
For example, Academician Wang Xiaoyun, a top cryptography expert, has single-handedly made the cryptography of Yuxia Kingdom in District 9 a world leader.
In the early years, District 1 claimed to have developed a set of MD5 encryption algorithm technology, claiming that it was the most secure algorithm in the world, and declared that "no one will crack it in 100 years."
This attracted the attention of the world, and many experts in the field of cryptography rushed to study it. Some scientists led their teams to study it for more than ten years without success, but Wang Xiaoyun easily deciphered it.
Later, after learning that MD5 had been cracked, District 1 urgently came up with another set of top encryption algorithms, SHA-1.
SHA-1 is more powerful and complex than the previous MD5 algorithm. Countless top cryptographers came to challenge it. Most people couldn't advance after counting 40 steps, but Wang Xiaoyun still cracked it easily.
And the reason for this cracking made the first area vomit blood. The reason was simply because the password goddess was bored during confinement, so she took out a pen and paper to write and draw, and then it took only two months to complete it.
This extremely complex encryption algorithm was cracked.
But today, District 1 upgraded the encryption algorithm again.
Not only have the rules and algorithms been redesigned, but double encryption has been performed to incorporate huge functions and algorithms into it.
This kind of encryption method is no longer pure cryptography, it involves other aspects of knowledge. Even top cryptography experts, even the goddess of cryptography, are unable to break this kind of encrypted message alone.
But fortunately, with such talents, Xu Chuan does not need to worry about cryptography and encryption work.
He only needs to find the rules behind the encryption of the double function algorithm and establish a targeted mathematical model.
Regarding this, Xu Chuan is still confident enough.
He comes from twenty years later. Although he did not major in mathematics in his previous life, at Princeton, he had access to the world's top and most cutting-edge mathematical knowledge at any time.
In Princeton, countless mathematics conferences are held every year, and countless geniuses and mathematicians convey their ideas and results there.
Functions are one of the important branches of mathematics.
From the early emergence of functions to the seventeenth century when Galileo defined the concept of a function or variable relationship in his book "Two New Sciences", functions have never left the core stage of mathematics.
If mathematics is the foundation of all disciplines, then functions are the soul of mathematics.
It can be said that as long as there is a mapping relationship between two number sets, they are called functions.
The essence of a function is to try to establish a mathematical tool to describe the 'causal relationship' between related things.
Causality is one of the most important laws in human cognition of things.
Why is it important?
In simple terms, it is because discovering and describing causal laws can bring human beings the ability to "predict".
For example, if a function describes the movement of a car, as long as the function argument contains rich parameters such as time and movement speed, we can go back to 5 minutes ago or predict where the car will be in 5 minutes.
If it is more complicated and loads more parameters, the function can even predict a person's actions and what time you will do tomorrow.
Before the invention of this mathematical tool, it was almost impossible to accurately describe this relationship.
...
In the mathematics room of the Information Security Department, Xu Chuan listed the information in his hand on the table in front of him.
One side is the original ciphertext, and the other side is the translated mathematical problem. Each piece of information is unique and there is no duplication.
Xu Chuan carefully studied the mathematical problems after the transfer.
From basic exponential functions, logarithmic functions, power functions, trigonometric functions, inverse trigonometric functions... to complex hash functions, symmetric functions, Gaussian functions, max, min functions, Euler functions, etc.
These mathematical puzzles include a variety of function puzzles.
But he was not intimidated by complex and changeable functions. Xu Chuan knew very well that most of the most complex functions are composed of basic functions.
Although the function problems in front of us are irregular, the first area can use these various function problems to encrypt messages, and can send a large number of useless messages to interfere with other countries. They must have something in their hands.
Generate mathematical rules for various function problems in large batches.
He does not believe that an ordinary person performing a task has the mathematical ability to decipher and solve these mathematical problems.
So calm down and search slowly, and you will surely find some clues.
Although from a mathematical point of view, perfect things exist, they cannot be created in reality.
It's like there are definitions of infinity and infinitesimal in mathematics, but can you write a number that represents infinity or infinitesimal?
