Cultivation little Taoist

Chapter 445 Complicated Encryption Method

"I... I can't untie it..." Hou Anqi replied in a muffled voice, at the same time she turned around and pouted her butt: "I'd better let you beat it, I'll recognize the flower when it blooms."

"You're almost eighteen, and you're ashamed of a man with your ass pouted, so turn around quickly." Ye Feng couldn't help crying or laughing, "Aren't you quite confident just now, why did you get scared after just one look?"

"It's not that I'm cowardly, but it's just that without a codebook, there's no way to decipher it, because the result can't be obtained by cumbersome computer calculations." Hou Anqi replied seriously.

"How to say?"

"This kind of ciphertext is called one-time pad, or OTP for short. It is an encryption algorithm in cryptography. The plaintext is composed of random keys and used only once.

This method was discovered by Frank Miller in 1882 and is still used today.In theory, this cipher is unbreakable, and its security has been proven by Claude Elwood Shannon.

Although its theoretical security is beyond doubt, it has the following problems in practice:
The text used for encryption, that is, the one-time pad, must have no specific rules. It can be a string of random numbers, a sentence, or an English classic.

It must be the same length as the file being encrypted.

The text used for encryption, that is, the codebook can only be used once, and it must be carefully kept secret from non-related parties. When it is no longer used, the text used for encryption should be destroyed to prevent reuse.

Therefore, these problems that can be easily found do not exist in this ciphertext at all. According to my guess, the Arabic numerals should correspond to Chinese pinyin, so it is impossible to find a cipherbook with the exact length corresponding to it. , can only be self-created. "

As Hou Anqi said, Ye Feng seemed to understand a little bit, how does this OTP work?
"First of all, you must have a one-time pad to encrypt the file, and then mix the letters in the one-time pad with the letters of the encrypted file in sequence according to a pre-agreed rule, one of which is the same The mixed approach is to assign letters to numbers,

The simplest is as in English, specify A to Z as 0 to 25 in sequence, then add the numbers represented by the letters on the one-time password text and the corresponding numbers on the encrypted file, and then subtract the number of letters in the language,

Suppose it is n, there are 26 letters in English.If a number derived from this is less than zero, add n to the number less than zero, and thus complete the encryption. "

The people present, including Ye Feng, were in a dazed state. The more Hou Anqi talked, the more she talked. Seeing that everyone didn't understand, she grabbed a piece of paper and a pen, and wrote down a page of a simple password book.

"For example, if you want to encrypt the sentence "Thisisanexample" in the message, and the one-time pad used for encryption is according to mine, it is MASKL, NSFLD, and FKJPQ.

Using the method of specifying numbers, the two can be converted as follows:

首先将“Thisisanexample”转换成19、7、8、18、8、18、0、13、4、23、0、12、15、11、4。

再将MASKL、NSFLD、FKJPQ转换成12、0、18、10、11、13、18、5、11、3、5、10、9、15、16。

两者依序相加后得到的讯息如下：31、7、26、28、19、31、18、18、15、26、5、22、24、26、20。

将以上得到的讯息模26后可得：5、7、0、2、7、5、8、8、11、0、5、22、24、0、20。

It also becomes FHACHFIILAFWYAU.This is the normal encryption process. If you want to decrypt, just follow the reverse operation of the codebook.

And this is full of numbers, that is to say, his codebook corresponds to numbers, and the numbers below correspond to Chinese pinyin or Chinese characters.

That's enough for me, uncle? "

After Hou Anqi finished speaking, she looked at Ye Feng and asked, Lin Xiaoyu was stunned, "Do you understand, little rascal?"

Ye Feng was a little embarrassed. In fact, he really only understood the general idea.

"I feel that this is not much easier than calculating the seven levels..."

Yuan'er was stunned when she heard that, and suddenly she clapped her hands: "An Qi, you are too powerful! Now brother Ye Feng definitely has no reason to beat us both!"

An Qi's brains turned quickly, and she knew that Yuan'er was trying to save the two of them: "Of course, the uncle is so kind, how could he be willing to beat such a smart little cutie!"

Ye Feng's face was full of black lines, it seemed that he would definitely not be able to do anything today, so he had to wave his hands, saying that you two should be careful in the future, and let me know that you are watching that kind of thing, it will definitely blow your ass!
The two girls looked at each other, knowing that they had escaped a catastrophe today, they stuck out their tongues: "I see."

Ye Feng picked up the diary and looked at it, remembering the last sentence Hou Anqi said, the numbers correspond to Chinese characters or pinyin, an idea suddenly popped into his mind.

"An Qi, let me ask you, if it's a diary, can it be used as a password book?"

"Diary?" Hou Anqi thought for a while, then suddenly opened her mouth wide: "Wow! Uncle, you are really amazing! I immediately understood the meaning of this OTP.

If you use a diary, it is really possible, as long as the year, month, and day on it are used as yuan numbers, and then the positions of the corresponding numbers are arranged according to the arrangement of rows and columns, then all of this will become a complete code book! "

"Damn!" Ye Feng cursed, looking at the handwriting in the diary that had been contaminated with chicken blood and cinnabar, this Gong Wenhua was really a chicken thief, and set up defense lines one after another to prevent the password book from being peeked at.

The first is to use insidious encryption to prevent hidden information from being discovered.

Afterwards, the OTP method was used to separate the two books. A code book was placed in the 447 dormitory until a knowledgeable person found out, and a plain text book was carried with him, and both of them had the aura of sinister art on them.

Obviously, he left the diary as a password book in 447, so he has a determination to keep the secret forever without being discovered. Also, if someone wants to break the insidious spell on the code book of 447 dormitory by developing, then It is equivalent to eradicating the real password—the diary, and the things recorded by Gong Wenhua will also disappear forever.

After all, after such a long time, anyone may go there, and the password book is likely to be lost or discovered by the Yin people.

Afterwards, Ye Feng was lucky, both of them had the aura of sinister art, but Ye Feng's original code book was robbed, and only the plain text was obtained. Naturally, the handwriting was also contaminated by the material and couldn't be read.

If Ye Feng first used the development method on the diary found in the 447 dormitory, then all this would be a dead end, the codebook would be polluted, and even the plain text would be useless.

What kind of information is Gong Wenhua hiding, and she has gone through so many circles.

And if the decryptor makes a wrong step, it is possible to bring the information into the coffin.

"We still have to find the code book that was taken away." Ye Feng muttered and got up, "We can only look it up from Fu Ting first."

Lin Xiaoyu nodded, Ye Feng looked back at the two girls, and said with a cold snort: "I will come back from time to time, if I find out that you watch that kind of stuff again, even Sanqing can't save you, as I said."

"Understood! I definitely won't read it! I'll read the book right away!" Hou Anqi said sweetly, and immediately promised.

Ye Feng glanced at the time and found that it was ten o'clock after he had been tossing around for so long.

"Don't read, reading at night is not good for your eyes, go to bed first, and review tomorrow."

"Okay! Thank you uncle for your concern!" Hou Anqi hurriedly replied.

Ye Feng went over and slapped this spooky little girl: "If I want to find out that you have ruined my family's fate, just wait for me!"

Just as Hou Anqi wanted to express her dissatisfaction, Ye Feng said to Yuan'er: "And you! Don't think that everything will be fine if you get recommended, prepare for college courses, and don't think about things in your little head!"

"Oh." Yuaner replied with pouted lips.

Ye Feng and Lin Xiaoyu went downstairs and got into the car, and continued to return to Binhai Medical College. Lin Xiaoyu couldn't help laughing all the way: "Hahaha, little rascal, I didn't expect you to have this side. You looked so much like a grumpy uncle just now. .”

"Is it easy for me? I caught ghosts and killed demons, and kept my younger sister in my body. Now I'm fine, but I have to educate bad girls. I'm so worried." Ye Feng said helplessly.

"Yes, yes, it's not easy, uncle, I'm also a bad girl." Lin Xiaoyu said pretending to be silly, and Ye Feng slapped her lower abdomen: "Then I will let the policeman arrest you and reform you! It doesn't hurt anymore, does it?"

"Hey!" Lin Xiaoyu covered her stomach in pain, and suddenly remembered the warm feeling when Ye Feng used the blood of Ai Ye Tianshi to pull out the ghost's corpse for herself, grabbed his hand and put it on her lower abdomen.

"You hurt me, make it up to me, and warm my stomach. I'm so sick." Lin Xiaoyu said in a low voice, and sure enough, Ye Feng's palm also had a warm feeling, which relieved her dysmenorrhea a lot.

Ye Feng saw that Lin Xiaoyu was really uncomfortable, so he didn't pull his hand back. He practiced the Thunderbolt Technique, and there was thunderbolt in the middle of his palm, which was indeed warmer than ordinary people's.

He drove with one hand, and when he arrived at Binhai Medical College, Lin Xiaoyu took Ye Feng's hand off.

"What's the matter, you don't need it anymore?"

"No, there is someone who needs it more than me." Lin Xiaoyu replied sullenly, then got out of the car and saw Xia Shihan running over.

Ye Feng didn't understand what she meant for a while, Xia Shihan came over and hugged Ye Feng: "Brother, where did you go, and it took you so long to come back."

"Uh... After a bit of trouble, I finally found the secret of that diary." Ye Feng replied briefly, looking at Lin Xiaoyu, "It's too late today, I'm afraid Zhai Yongyi has gone home early, we have to check the diary tomorrow Fu Ting's information."

"Why look up the information? You know she has a problem first, so just go and find her!" Lin Xiaoyu said bitterly, thinking of the one who might be the culprit for her dysmenorrhea.

"No, you can't startle the snake with this matter. I always feel that behind Fu Ting, there should be hidden the remnants of the real leader of the Golden Emperor Kingdom..."

(End of this chapter)