A nation's industrial development begins with junior engineers.

"Jingle Bell……"

"Jingle Bell……"

The red phone kept ringing.

"I just woke up from a dream... How did I fall asleep in the office again?"

Jiang Xia scratched his messy, bird's-nest-like hair, his bewildered eyes darting around, and it took him a long time to pull himself back to his senses.

Looking at the darkening sky outside the window, I yawned and picked up the phone.

"Hey?"

"Hmm? Kid! I can tell from your tone that you're still half asleep! I thought you were a hard worker, but it turns out you're just like me, preferring to lie down rather than sit! Ah~ hahahaha..."

A slightly quirky laugh came through the microphone, and Jiang Xia unconsciously chimed in, "Oh, Baoqiang, you finished your milk?"

"I'm the Listener! Not some Baoqiang. How...how did you know I drank milk?"

The person on the other end of the phone seemed to want to say something, but their voice grew softer and softer, as if they were being dragged away.

"Xiao Jiang, I'm Zheng from Bureau 701!"

"Oh! Director Zheng, hello!" Jiang Xia thought for a while before remembering the things at 701, that guy in black sunglasses who liked to show off, and that genius who got stuck on trivial details.

"Hehe, I called you today because someone wants to thank you. Thank you for freeing him from the maze. Come on, Jinzhen... Hey, kid, what are you hesitating for? Didn't you want to contact someone else...?"

There was no sound on the phone for a long time. Jiang Xia shrugged, put the receiver aside, and went to get some water to drink.

Tsk, what kind of liquor did this air force bigwig get? He didn't seem to have had more than a few drinks, so how did he get so drunk?

However, I didn't feel uncomfortable at all; on the contrary, I felt warm all over.

He picked up the half-full bottle of wine that was on the table, shook it casually, and the brown liquid, mixed with unknown medicinal herbs, began to swirl.

Spin and spin, spin and spin.

Jiang Xia stared at the swirling solid objects, lost in thought.

A timid voice came through the microphone: "Comrade Jiang Xia!"

"Yes, Comrade Jinzhen, right?"

Another barely audible soft "hmm" came from the other end of the microphone.

"Thank you. I have successfully derived a certain security algorithm. The relevant comrades are further deducing and verifying it based on the algorithm formula. However, according to the expired coded telegram, my algorithm is correct!"

"We also have comrades using this algorithm to analyze some recently intercepted..."

"Stop! Comrade Jinzhen. I've only done a few test papers. Don't make me go back to writing all those papers." Jiang Xia's remaining drunkenness was instantly sobered up.

Although he deeply respected the person who wrote the exam paper and found it incredibly easy to complete, Xiao Dai Mao still refused to do it again.

After all, that old man was already exhausted!

Is this little brat a case of settling a personal score under the guise of public office?

"Uh, uh, yes, I'm sorry..."

After saying that, the other person fell silent again.

Wow, these silent geniuses are really hard to deal with. Can't they even tell when someone is joking?

Jiang Xia scratched his head. "Forget it," he thought, "I'll try to steer the conversation towards modern cryptography. Someone like that, suddenly freed from the shackles that have bound them, could very well go to the other extreme."

Don't follow that guy who got hit by an apple and mess around with some vague and unrealistic stuff.

It's worth noting that Bureau 701 was still using the somewhat outdated Enigma rotary encoder system. Integrated circuits were almost out of the question, and not using the DES cryptosystem would have been a huge waste.

Perfect timing! Once the computer operating system developed by the Academy of Sciences is perfected, we'll need a way to encrypt it, otherwise all that money will be wasted.

Hehe, I'm really looking forward to seeing China's cryptography geniuses battle against future "folk masters".

Jiang Xia quickly wrote the words "public key cryptography" in his notebook, followed by the RSA algorithm. After thinking for a moment, he added a series of terms such as ElGamal, elliptic curves, and bilinear peer-to-peer public key cryptography.

Hehehe, come on, genius, have fun.

"Jinzhen, have you seen the rough draft of the DES encryption algorithm I wrote?"

"Look, I saw it! The director just gave me the data. I glanced at it briefly when I was on the phone with you. Comrade Jiang Xia, you're amazing! Computers have become this powerful? Plaintext data can now be encrypted in 64-bit groups! This is a much higher level of encryption than the Enigma machine's three regular wheels and one reflective wheel..."

Sure enough, when the conversation turned to Jin Zhen's expertise, this genius immediately became very talkative, praising Jiang Xia's DES encryption algorithm to the skies.

The little guy with the tuft of hair squinted his eyes. "That sounds nice! I love it! Say more!"

Wait, what the hell is wrong with your brain? You just got your hands on it, glanced at it, and already figured out its basic encryption method! You can even compare it to Hans Nyan's Engelma machine?

Bah! Is this what geniuses do when they crush their opponents?

But, genius, you should have looked further ahead!

Unwilling to admit defeat, Jiang Xia shook his finger, regardless of whether the other side could see it or not:

"Hey, that's superficial! Comrade, you've only noticed this surface phenomenon? Didn't you discover the important role the NB-1200 structure plays in the encryption process?"

"NB-1200?"

"Yes, it involves dividing the data block into two parts, left and right, and gradually converting the plaintext into ciphertext through multiple iterations (16 rounds) of encryption. Didn't you notice that the encryption and decryption processes are the same for this structure, where you just need to use the reverse order of the subkeys during decryption?"

At this point, even Jiang Xia, whose skin was as thick as a city wall, couldn't help but blush. The NB-1200 structure was actually the famous Feistel structure from the DES encryption algorithm, which was created by a guy named Horst Festor from the movie *The Big Blue*.

However, that was around 73.

Xiao Daimao originally wanted to name this structure after himself, but a strange sense of guilt led him to choose the ambiguous code name NB-1200.

"Oh! I noticed that you also introduced the concepts of substitution box and permutation box. Although I don't know how a computer can replace 48-bit data with 32-bit data, with the concept of permutation box, it's a bit like the Enigma cipher machine that uses 3 regular wheels and 2 reflective wheels."

"In this way, the three different directions of the rotors create 3 different possibilities;

There are 6 possibilities for the different relative positions of the three rotors;

Adding the concept of two types of boxes, and the possibility of swapping two letters in pairs, the number of possible combinations of six pairs of letters is enormous—there are… ways!

At this point, Jinzhen paused, counted on her fingers, and continued excitedly, "So there are a total of... well, that's a really big number, I need to calculate it for a while..."

"Haha, hard to calculate, right! Use Big Yellow's clone! I'll tell you, you type..."

There are a total of 100,000 possibilities! Approximately 100 trillion possibilities.

"Comrade Jiang Xia, your algorithm is truly unparalleled in the world!"

your sister!

The little idiot on the other end of the phone was in tears. "You're unbeatable! Do you have a quantum computer in your head? How did you calculate those numbers in just a few breaths...?"

Even "Big Yellow" can't come to this answer now!

It'll definitely get stuck at some calculation point and start clicking away! A little while later, its brain (transistors) will definitely unleash a few fireworks to show you what's what!

So, you can just do some calculations and then recite that string of numbers?

Damn author, change the protagonist! He's the chosen one...