Siheyuan: I eat melons while doing scientific research

Chapter 1405 isn't as good as you say (4k)

Gao Zhendong pondered for a long time, then clenched his fist.

Do it! But there's no rush.

Anyway, people outside aren't even very good at thermal imaging yet, so there's no need to rush.

However, now that we have these things, even just a glimpse of them, they can save our colleagues in related fields a lot of time and energy in the future. These unseen resources of each colleague are extremely valuable. Perhaps just a few pages of these papers can help a senior who once left with regrets and could only wait for his students and younger generations to realize his ideals to bear his own fruitful results in the prime of his life.

Their students and successors can then stand on their shoulders and climb to even greater heights.

Gao Zhendong put the rest back into the storage warehouse. If they take their time, the comrades at the Third Factory will be busy.

He compiled the extracted radar stealth coating information into an encrypted compressed file, saved it on a floppy disk, and then called the comrade in the internal security department of the Third Factory.

Even with all the good ideas in Gao Zhendong's head, he was extremely careful with this kind of content. Even if it was an encrypted file, he would put it on a floppy disk and send it physically through a confidential channel.

In this way, the reliability is basically the same as the original key components, while the encrypted floppy disk greatly improves the security capabilities.

The internal security detail of the Third Factory had people from all over the world, so Gao Zhendong could always find the person he was looking for.

Soon, the two comrades arrived at Gao Zhendong's place and took away the flimsy floppy disk.

At roughly the same time, at the Military Communications Institute, two comrades were staring blankly at a computer.

"It's still slow. When transmitting real-time or near-real-time messages, the timeliness is still too poor, which limits the applications."

"The C6132N is slightly better, but there's no fundamental difference."

"It's already so fast, how come this algorithm requires so much computation?" one comrade said with a sullen face.

They had a very good idea, and after hard work, combining the latest network transmission and exchange protocol achievements, the principle and process were both successful, but there was only one part that didn't work.

--speed.

Their idea was to use JGM-2, an elliptic curve public-key cryptography algorithm that is not publicly available, to transmit encrypted messages using public-key cryptography.

However, they forgot one thing: the JGM-2 algorithm is extremely slow, and it's completely unusable for chips like the C6108 or microcontrollers.

If the message is not time-sensitive, it's easier to decrypt it slowly. However, if it is a real-time message or a near-real-time message, the computational load required by this algorithm is still too large.

By the time the message was decrypted, it was too late.

"How about we go find that comrade?" one of the comrades asked.

"Isn't this a bit of an exaggeration? This isn't a big deal, is it?" Although he didn't name names, the other comrades knew who he was talking about.

"Don't underestimate it. If it can't even solve the problem of the latest computer like the C6132N, then it's really difficult to solve from a capability standpoint. Besides, given the price and production volume of the C6132N, I doubt we'll be able to use it extensively in mainstream terminals, right?"

The C6132N is slightly better, after all, it's much faster, but machines of this level aren't really suitable for widespread use in ordinary terminals.

Forget about ordinary ones, even slightly high-end ones won't do.

Even foreign countries can't freely use C6108-level missiles. In comparison, the comrades at the Military Communications Institute and our troops are already very fortunate.

The other comrades remained silent. As for computing power, a metric that can overcome anything, it's really a matter of either having it or not having it.

Even the smallest problem becomes virtually unsolvable when it comes to the hard factor of insufficient computing power.

If we're talking about directions, there are probably only two: optimize algorithms and increase computing power.

These two directions are probably difficult for the colleagues at the Military Communications Institute to achieve right now. They cannot optimize the core of the JGM-2 algorithm; simply optimizing the computational code is not very useful, given the algorithm's inherent time complexity.

As for improving computing power... hehehe, they can only wait now, and judging from the release time of the C6132N, it's probably impossible to expect any new devices in the short term.

"How about... we try to get in touch?" That comrade was very easy to talk to, very enthusiastic, and always willing to help, provided that he was available and in Beijing.

The staff at the Military Communications Institute finally got through to Gao Zhendong by phone, expressing their desire to consult him about a problem they were facing.

Gao Zhendong was quite pleased. If there were problems, it meant there was action to be taken; without action, there would be no problems. Besides, he also wanted to refresh his mind, so this was perfect.

"What's the problem? Go ahead." This call came in via a dedicated line; if it's not something extremely sensitive, you can just say it directly on the line.

"Chief Engineer Gao, it's like this..."

The comrades gave a general account of the problems they encountered, leaving Gao Zhendong somewhat bewildered.

Why do you use asymmetric encryption algorithms in real-time or near-real-time communication devices?

This is definitely a difficult problem. Not to mention the capabilities of the devices we have, even in the 21st century, those embedded CPUs with astronomical computing power wouldn't dare to take on this challenging task.

The comrade on the other end said, "Our original idea was to implement a dynamic key system."

Before he could continue, Gao Zhendong interrupted him: "So, you want to dynamically distribute keys and change them as needed, right?"

"Yes, yes, that's exactly what we mean. We think this can greatly improve the security of advanced communication terminals." The comrades from the Military Communications Institute were very happy. It was so convenient to talk to Chief Engineer Gao; he could guess what they meant without them even having to finish speaking.

"Just as I thought," Gao Zhendong laughed. "Have you considered the possibility of using the GM-1 symmetric encryption algorithm to solve this problem?"

The colleague from the military communications institute replied, "We have considered it, but that would require sending out the new symmetric encryption key when changing the key. However, if one or more communication terminals do not receive the key change message, they will be unable to decrypt the message after the key change."

Gao Zhendong laughed on the phone: "That's not what I meant. What I meant was that normal encryption and decryption still uses GM-1. You just need to use the JGM-2 encryption algorithm for encrypted transmission when changing the key. In this way, for the terminal, the pressure of decryption is only on the message that changes the key, and daily encryption and decryption can still use the fast GM-1."

He didn't know why his colleagues hadn't thought of this solution. Any reason was possible, and there was no need to delve into it. Even the smartest person wouldn't occasionally do something like replacing a 16mm steel cable with two 8mm cables; it wasn't unusual. Gao Zhendong himself had made mistakes before, so his priority was solving the problem. How the problem arose was unimportant.

The suggestion he made was a dynamic key encryption method that Gao Zhendong had used in various computer systems in his previous life, which effectively avoided the problem that asymmetric security is high but cannot be calculated.

Gao Zhendong's words almost made the other comrades want to crawl into a hole and disappear.

It's that simple?
It really is that simple, but I just didn't think of it; my thinking was a bit too rigid.

"Chief Engineer Gao, this...we'll go try it right away!"

Gao Zhendong smiled and smoothed things over, saying, "Don't worry that running two algorithms at the same time will increase the program's capacity requirements and thus affect the cost of the equipment. Semiconductor technology is developing, and ROM chips are gradually becoming less of a novelty."

His words made the comrade opposite him blush even more; General Manager Gao was actually quite nice to the workers.

Amid a string of thanks, Gao Zhendong hung up the phone in high spirits, adding another military-related joke.

Although he could only savor these jokes in his own mind, it didn't affect his happy mood at all.

Not long after I hung up the phone, it rang again...

The phone rang again.

So, the moment you think about changing your mindset, all of this comes to pass, right? This is a really thorough overhaul.

Someone came to him with documents from the committee, and it was someone he knew at least, someone from a familiar organization.

A short while later, the three comrades, led by the internal security guard, met Gao Zhendong in the reception room.

"Committee Member Gao, hello, we are from the Radar Institute..."

Although the paperwork was complete, the visitors still introduced themselves. The leader was surnamed Meng and worked in the imaging field of the radar institute. The other two were members of his team.

"Hello, Engineer Meng! Hello, Engineer Meng! You've come here today because..."

"Chief Engineer Gao, our institute's chief engineer brought back a notification from the commission that you had approved the use of synthetic aperture radar. You mentioned the idea of ​​synthetic aperture radar at a meeting?"

Gao Zhendong remembered that he had once proposed the idea of ​​radar imaging in the anti-submarine patrol aircraft technology. Later, the chief engineer of the radar institute also mentioned synthetic aperture radar to him and agreed to exchange ideas later.

I just didn't expect the time gap to be so long.

"Ah, yes, yes, that's right. You're the guys your boss was talking about, the ones working on synthetic aperture radar, right?"

Gao Zhendong recalled that the chief engineer of the radar institute had said that although some colleagues were working on it, it was quite difficult. Of course, he couldn't say that to their faces directly; the colleagues at the radar institute could say it themselves, but for Gao Zhendong to say it was a bit...unpleasant.

It's not surprising that it's difficult. After all, the first image of this technology was only taken in 1957. So far, it's not a short time, but it's not a long time either. It's normal that we're making slow progress.

Originally, our first synthetic aperture radar prototype was completed in 79, and we obtained our first image. However, we didn't get any truly good images until 91.

To be honest, given this development process, the fact that there are comrades working on SAR now is slightly beyond Gao Zhendong's expectations.

Engineer Meng nodded and said, "Yes, yes, that's us. It's just that progress is very slow and the difficulty is very high. So when we heard from the chief engineer that you had related ideas, we were overjoyed..."

I'm certainly happy, after all, Committee Member Gao has made outstanding achievements in the field of radar, both in theory and in practical devices. It can be said that the pulse PD radar that the Air Force comrades love so much is the work of Committee Member Gao.

Theory of pulsed PD, ground clutter processing algorithms, traveling wave tubes, planar slot antennas, digital signal processors...

That's why Meng was extremely excited when the chief engineer told him that Committee Member Gao was interested in SAR.

Others may be interested in something but it's just an interest, but Gao is different. His interests can be transformed into results, and his transformation ability is extremely strong.

"...So we have carefully prepared our current research situation before coming to visit you." Meng's words expressed his respect for Gao Zhendong, and also explained why it had taken so long to come.

It would be such a waste to come here unprepared.

Gao Zhendong didn't think they were too late; a few days earlier or later wouldn't make much difference: "Oh, thank you for your trouble. Let me tell you about the situation. To be honest, I'm quite pleased to see that some people in China are working on synthetic aperture radar."

He was genuinely surprised, but his words were a bit overwhelming for Meng and the others.

"Committee Member Gao, it's not as good as you make it out to be. Our focus is on radar imaging, but not actually synthetic aperture radar. We have ideas for synthetic aperture radar, but we don't have the means to implement them..."

There's no benefit in bragging to Committee Member Gao. The best approach is to be truthful and not fill in zeros. If you brag and Committee Member Gao says, "Oh, it's already solved? Okay, next," then you're in trouble.

Hearing his words, Gao Zhendong suddenly pictured a strange child with silkworm-like eyebrows in his mind, who said awkwardly, "Actually, it's not as good as you say..."

Damn, why did I think of that? Is it because Engineer Meng's eyebrows are also quite thick? Gao Zhendong quickly shook his head, trying to banish the little brat from his mind.

It seems that Engineer Meng is a very practical person. There are many approaches to radar imaging, but for a long time, the most practical one has been SAR, as well as the family of technologies based on SAR such as ISAR, SAR-ISAR, and InSAR.

"So before this, your approach was real aperture radar imaging?" Gao Zhendong asked.

Real aperture radar imaging, simply put, is imaging using the actual physical aperture of a radar.

"Yes, but the prospects and effects of this technology are very limited. After working on it for a while, there is no possibility of it being practical."

This judgment is basically correct. Not to mention ordinary radar, even the star of Gao Zhendong's time-travel radar - the active phased array radar - has such a poor effect when using real aperture imaging.

The reason is simple: if other conditions are fixed, to achieve high imaging resolution, the antenna aperture must be increased. In other words, the antenna size must be large enough. Obviously, this physical requirement greatly limits the future of real aperture radar imaging.

After all, imaging radars are often dragged around and flown around, so the word "large size" is a death sentence.

(End of this chapter)