Chapter 296 Captain Lingyin’s class: How to cover and crack the password.

Chapter 296 Captain Lingyin’s class: How to cover and crack the password.

Captain Ling Ying smiled and wrote a six-digit number on the blackboard: "".

"Students, this may seem like a simple six-digit password, but after careful design, it can become an almost insurmountable barrier. Now, I will show you how to set up five layers of complex password protection for this set of numbers."

"At the first level, we use a simple digital substitution encryption method. The ten numbers from 0 to 9 correspond to different letters, such as 0 corresponds to A, 1 corresponds to B, and so on, 9 corresponds to J. Then, it becomes BCFEDG. This is the most basic first level. The cracker must first be aware of this substitution pattern."

"In the second layer, we introduce shift encryption. By shifting the entire group of letters backward by three places, BCFEDG becomes FHJILN. This layer requires the cracker to try various possible shift numbers and find the correct one."

"In the third layer, we use XOR encryption. We choose a specific number, such as 7, and XOR the ASCII code corresponding to each letter with 7. For example, F has an ASCII code of 70, and after XORing it with 7, we get 63, and the corresponding letter is C. After this layer of encryption, FHJILN becomes CVKQPR."

"At the fourth level, we use hash function encryption. We select a common hash function, such as SHA-256, and process CVKQPR to obtain a long string that looks irregular. This level is extremely difficult to crack because the calculation of the hash function is irreversible. The cracker needs to go through a large number of attempts and calculations to find the possible original text."

"For the last layer, we use dynamic encryption. We set a time parameter, and the encryption rules change every minute. For example, within a certain minute, all letters become their previous letters. If the current letter is Z, it becomes A. This requires the cracker to complete the cracking in a very short time, otherwise he has to start over."

Captain Ling Ying looked at the students with a sharp gaze, "These five layers of encryption are stacked one on top of another, and each layer is extremely difficult to crack. To crack such a code, you need to have a deep knowledge of cryptography, strong computing power, and sharp logical thinking."

The students were stunned and deeply felt the mystery and complexity of cryptography.

Captain Ling Ying crossed his arms and continued, "Of course, the basic five layers just shown are sufficient for most situations, as they are used to protect information of general importance. However, if it involves core secrets, top scientific research results and other crucial content, we can also set higher levels of encryption. For example, 5 layers, 10 layers, or even more than 50 layers.

Imagine that when the enemy tries to crack the code, each layer is like a solid fortress, which takes a lot of time and energy. Before they can crack it, we generate more layers of codes to cover them, thousands and tens of thousands of codes stacked on top of each other. It's like a maze that is always changing and growing, making it impossible for the enemy to find the exit and crack the secrets.

Such encryption methods can provide almost absolute security for our important information. It makes the enemy lost in this seemingly endless sea of ​​codes, so that we always occupy the commanding heights of information security. "

Captain Ling Ying looked serious and said, "Next, I will explain to you how to try to crack the five-layer password we just set. We will still take the result after five layers of encryption as an example.

First, the first step in cracking is to perform cryptanalysis. Observe the encrypted results and look for possible patterns and features. For example, whether there are repeated character patterns, or whether the frequency of certain characters appears abnormally.

For the first level of digital substitution encryption, we need to guess the possible correspondence between numbers and letters through a lot of attempts and reasoning. This may require us to have some understanding of the common rules of number and letter substitution and make inferences based on the context.

After breaking through the first layer, we face the second layer of displacement encryption. We can start with common displacement numbers, such as 1, 2, 3, etc., and observe whether the results obtained through reverse displacement operations make sense.

The third layer of XOR encryption is relatively complex. We need to understand the characteristics of XOR operations, try XOR operations with different numbers and encrypted characters, and look for possible patterns.

It is extremely difficult to crack the fourth-layer hash function encryption. Due to the irreversibility of the hash function, we usually need to use a brute force method, that is, generate a large number of possible original texts, calculate their hash values, and compare them with the target hash value.

The last layer of dynamic encryption is the biggest challenge. We need to accurately grasp the time parameters while also dealing with the ever-changing encryption rules. This may require us to build complex mathematical models to predict changes in encryption rules.

Cracking such a five-layer code requires great patience, rich knowledge and strong computing power. Students, the world of cryptography is full of challenges, but also full of fun and a sense of accomplishment. "

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