Chapter 44 Wrong modeling method (updated in advance, I have something to do in the morning)
"How can I help? Do you need this kind of problem-solving method? If you want it, just use it."
Xu Chuan tried his best to suppress his emotions, pretending to be a high school student who heard the news for the first time and replied with surprise and confusion.
He also didn't expect that something that was supposed to happen after IMO would actually happen in advance.
Now that I think about it, the training time for this National Congress has been inexplicably extended by ten days. I'm afraid it's because of this.
Moreover, the college knowledge points in the function class should be prepared for geniuses like them. The country hopes to focus on cultivating a group of mathematicians in this field.
"We really need your help. This mathematical method of simplifying the solution of the Dirichlet function is very important. We need you to explain the key to it."
"In addition, if you can, it's best to go with me to the Information Security Department. There are dozens of mathematical geniuses and mathematics professors gathered together to decipher those encrypted messages. They also need this method."
"After all, before the mathematical model has been established, this method can greatly simplify the difficulty of deciphering the encrypted information of the Dirichlet function."
"Or, can you join the Information Security Department?"
The paper used for this kind of paper card is much thicker than ordinary paper. Based on the thickness of a paper card of 0.05 mm, the stack in his hand has about forty sheets.
Zhang Weiping looked at Xu Chuan blankly and couldn't help but swallowed. What kind of monster is this?
"Can I look at the questions first?"
"From the paper card just now, I saw a completely different encryption method."
A few simple sentences can clearly explain their work.
Xu Chuan took the paper card and glanced at the quantity.
"If you want to make a numerical model of all the changes, it is simply impossible to do it, even if you summon mathematicians from across the country."
Zhang Weiping looked at Xu Chuan and asked.
The questions on almost every card are a mixture of at least two or more types of mathematical problems. The questions are intricate and complex, and every question is very difficult to solve.
Zhang Weiping replied: "At present, we intercept dozens of such encrypted messages every day, but most of the encrypted messages are useless after being decoded, and useful information only occupies a very small part of them."
These paper cards have already been deciphered and are from the past, so there is no problem in showing them to him.
Xu Chuan thought for a while and then said: "Actually, it can't be wrong."
"It's very simple and easy to deduce."
Xu Chuan asked as he flipped through the paper cards in his hand.
He noticed before that there was a thick stack of paper cards in the box, and they should all be the same kind of questions he just did, but the types might be different.
Zhang Weiping frowned and asked in surprise. If the mathematical ability of the student in front of him hadn't really conquered him, he would probably have turned around and left.
Is there really such a terrifying genius in this world?
Hash function + hash transcoding
New Elliptic Curve Algorithm ECC + Symmetric Function
RC2/RC4 symmetric algorithm + single compression function
"Are these all accumulated in the past?"
"But there is often a useful piece of information mixed in with a large amount of useless information. No one knows which piece of information is useful until it is deciphered."
Although he knew about information security before his rebirth, he had not read these topics, so he was still quite curious.
"So I guess you are currently trying to model these encrypted messages that have been deciphered, and then use these numerical models to find the mathematical scale behind them, or in other words, use these numerical models to decipher the other party's encrypted messages."
Now a senior high school student wants to overturn this view, which is ridiculous no matter how you look at it.
"If your approach is to find the mathematical laws behind these encryption methods, and then make mathematical models based on the mathematical laws, you do not need my method."
"The reason why I say there is a problem with your modeling method is because the changes in functions and algorithms are almost endless."
Just like the question he just did was a mixture of Dirichlet function + base transcoding, the questions on each of these paper cards are different, and there are many mathematical problems mixed in.
Zhang Weiping looked at Xu Chuan dumbfounded and asked, "How did you know?"
Xu Chuan shrugged and continued: "First of all, the simplified method to solve the Dirichlet function is helpful for your modeling."
"Translation, transformation, expansion and contraction, rotation, symmetry, asymmetry, with just a slight change, it is almost a completely new function. Teacher Zhang, you know this better than me."
"Manual deciphering consumes too much manpower and energy, so modeling is the only way. The computing power of computers far exceeds that of humans. It can help us decipher encrypted messages in time and catch those people."
"But I feel that your current modeling method may be wrong."
"If I guess correctly, your approach should be to make a mathematical model for every method that has appeared so far, and then use these mathematical models to solve the encrypted information, right?"
Xu Chuan did not answer the question directly, pointing to the black box in the corner and asked.
"But in fact, after solving the Dirichlet function modeling using the simplified method, it can only decipher the encrypted information related to the Dirichlet function."
"How to say?"
"The most direct solution is to find the most basic mathematical rules used in these encrypted messages, and then model them based on it."
"I don't know much about programs and information encryption, but I still know some knowledge about mathematics and mathematical modeling."
Xu Chuan ignored Zhang Weiping and then analyzed: "In addition, I also speculate that these encryption methods may be abandoned and no longer used every once in a while, or they will be used again after a long period of time. This
The points can be seen from the questions on the paper card.”
Zhang Weiping nodded, walked over and opened the black box with the key again, took out a stack of paper cards and handed it to Xu Chuan.
Establishing a mathematical model to decipher the encrypted information in the first area is the consensus of everyone in the Mathematical Society and the Information Security Department.
"Well, this is just a part of it. It has been selected and is of average difficulty. There are also some more difficult ones at the Information Security Department."
After turning over the paper card in his hand, Xu Chuan handed it back and said, "Although I don't know how your modeling work is going now."
"Like now, you build as many digital modules as the other party sends out encryption functions and algorithms. I personally feel that this method is really not very useful."
"Perhaps if we build more numerical models, we can indeed find some hidden mathematical rules, but I'm afraid it will take a year or two to accumulate data."
Xu Chuan shook his head and said that he probably knew why it took two years for this matter to be resolved.
It is estimated that this stupid method was used to solve the problem completely.