Chapter 551: Crypto War II

Therefore, this time the Prussians are smarter. This simple correspondence relationship cannot solve the problem how many times, because people can always trace the source to find a one-to-one correspondence to determine the password. So, they came up with the adfgv frame password. The frame of this password is a 5*5 letter matrix corresponding to 26 English letters. What? You say there are only 25? That's easy, just let i and j correspond to the same letter.

One of the very important reasons why it is called adfgv password is that the horizontal and vertical coordinates of this 5*5 frame are represented by these 5 letters. According to the letters in the plaintext, replace it with the horizontal and vertical coordinates of this frame. This becomes the first step of encryption. In fact, this encryption method is easy to crack. This is the simplest classical encryption method, but it is a pity Yes, this time the Germans added the key again! The so-called key is another shift code. When using the key to shift, use the key character to add an extra column to the original coordinate system, and then write the first encrypted cipher text in the order of 5 lines Go in, and then copy the secret key in another alphabetical order to form the final ciphertext.

The key to the difficulty of deciphering this kind of password is that the key and the shift password change every day. If you find it in time, it is of no use, or if you get the 5*5 initial corresponding form, it is not very meaningful. Just write a 5*5 form, it is possible to crack it, but if you use guessing or simply find a one-to-one correspondence method, it is difficult to guarantee timeliness and accuracy. What to do in an age without computers?

There is only one way, and that is to find the same telegram at the beginning, because it shows that they use the same sub-decryption key and shift key, and then filter them through mathematical methods. Of course, an objective condition is also needed here, that is, there is enough information to repeatedly appear, and there is enough material to decipher, which is why the Bavarian intelligence team failed to decipher the other party. During the accumulation of materials!

From the sixth week, the whole thing turned around. On the 38th day after the start of the game, the prince gave the first deciphered telegram to the Kaiser. Two days later it was the second letter. Then before the end of the week, 6 telegrams were sent to Berlin! This means that a full 120,000 marks has been transferred from the Kaiser’s account to the prince’s name. And when the seventh week came, in just one week, 18 telegrams were deciphered! In less than two weeks, the Kaiser lost 500,000 marks!

"Who can tell me what's going on? Didn't I ask you to change the comparison table and the key? Why is the other party's deciphering speed still so fast? We sent the telegram in the morning, and when I had afternoon tea, The Bavarian side will send the plaintext! I feel that our IQ is insulted, and the other side looks at us with a foolish look! This is our shame! The empire uses high funds for you and your so-called so-called The cryptographers of Japan provided the best conditions, but see what you did?" the Kaiser said angrily.

"It’s now, it’s the seventh week, and you can’t even decipher a single telegram, but what about Bavaria? They have deciphered 24 telegrams from us! No matter how we change the frame and the key, we can’t change this. As a result, then I can only say that your method failed. The encryption method you proposed is not trustworthy at all!" At this point, even the Kaiser, who has no research on cryptography, knew he had lost, because The other party has adapted to this encryption method, and the space for expansion of this password is too small, so no matter how you change it, you cannot fail.

"Theoretically, the 5*5 correspondence table will have enough changes. We can increase the difficulty of deciphering by randomly changing the correspondence method. However, the information needs to be transmitted stably. The correspondence table itself cannot be changed at will. The staff is finally passed to a division-level commander. If we want to change the correspondence table without authorization, it will be a very cumbersome process."

"And also because of the 5*5 comparison, our shift password can only be 5 digits. The other party can find the breakthrough through enumeration and statistics. If it corresponds to the facts, as long as one of the letters can be found Key, then other information using the same key will have no confidentiality at all. We admit that the other party is capable of deciphering, but what I must say is that the Kingdom of Bavaria is more talented in encryption, and they got it. A brand-new encryption method, this method is almost impossible to crack when we saw it! Because every phrase is different in every telegram!" Shi Lifen was convinced that he lost, he did not justify his failure. It is a clear admission!

"That means, we lost again?" The Kaiser's face showed an unbelievable expression. "But you have just said that the ciphertext of each phrase is different. This shows that ~www.wuxiaspot.com~you have already Some phrases have been confirmed, is that right?"

"Yes, the Bavarians are very confident in their cryptosystem. They will even take the initiative to provide us with the correct answer after 3 days, and then we will push back the ciphertext according to the plaintext given. But unfortunately, each of them The letter correspondence sequence of the ciphertext telegram is chaotic, at least we can’t see the rule, and when we use the same key, the correspondence of the file is certain. Even if we change the key every day, we still cannot generate them. Effect." Shi Lifen lost this time but was convinced.

"Okay, okay, okay, we failed again! Let's see who our general staff is composed of! Finally, I will give you another week. I hope you can at least see something." Although the emperor knew that Shilifen was helpless by saying these words, he still didn't want to give up.

"I will try my best." Schlieffen said in a deep voice.

"His Royal Highness, if nothing goes wrong, His Majesty William should almost be unable to stand it?" At the same time, at the Neuschwanstein Castle, Earl Schelling said to him with the telegram just deciphered today.

But the end result was no accident beyond the Prussians. They had nothing to do with passwords that had never been repeated, their correspondences were extremely confused, and could not be decoded by any existing mathematical methods.

"Go to Bavaria and get the new encryption method! I want to know where we lost!" the Kaiser ordered.

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