The train driver in the courtyard

The weather station is now very large, with the telegraph room, logistics department, action team, and data room all arranged in an orderly manner.

Li Aiguo has been with the weather station for a long time, but there are still many places he hasn't been to, for a simple reason.

In a classified unit like a weather station, you shouldn't go to places you shouldn't go, ask questions you shouldn't ask, and wandering around is a big no-no.

In some areas, special passes are even required.

For example, the inconspicuous little courtyard in front of him at this moment, located in the southeast corner of the weather station.

There is no address number, and no publicly disclosed department name.

Most ordinary meteorologists only know that this is a "confidential area" and that they cannot get close to it without the personal approval of their superiors.

The weather station was heavily guarded, with security personnel dressed in black Zhongshan suits stationed at the gate.

Li Aiguo followed behind Lao Mao, handing over his specially made ID, a hint of curiosity rising in his heart.

"This is the Dark Room." Old Cat nodded to the two security guards.

Upon hearing this, Li Aiguo instantly became excited.

The darkroom is the most mysterious and core department in the weather station responsible for deciphering codes.

Years ago, Li Aiguo intercepted an encrypted file on an international train, which was eventually cracked by a black room.

"Comrade train driver, this trip to the Black Chamber has received special permission from above," Old Cat explained to the security personnel.

Even though the security personnel clearly recognized Li Aiguo, they still examined the photo closely again before making way for him.

Li Aiguo followed the old cat into the courtyard, and he had only one feeling: quiet. It was so quiet here.

The courtyard is not large, with a small pavilion in the middle and a ring of blue brick bungalows around it.

Through the glass window, you can vaguely see the busy figures inside, but you can't hear any noise.

"Come with me." Old Cat said softly when he saw Li Aiguo stop and look around.

Li Aiguo quickly quickened his pace to catch up, and the two arrived at a spacious office.

The old cat didn't knock; he just pushed the door open and came in.

Li Aiguo was stunned at first glance; this office was too peculiar.

Rows of metal filing cabinets stand against the wall, containing radio secret message drafts, encrypted telegram copies, and records of foreign military communication frequencies.

On several long wooden tables pieced together, there were densely stacked calculation drafts, frequency records, and alphabetical tables for various languages.
At this moment, a middle-aged man dressed in a gray-black Zhongshan suit was sitting at the table, holding a pencil in his hand, quickly flipping through some pages and doing some calculations.

"Old Chen, have you deciphered that secret letter that was just delivered?" Old Cat strode over and asked bluntly.

The middle-aged man didn't even look up: "It'll take another half hour. Just find somewhere to sit and wait."

Li Aiguo raised an eyebrow, secretly marveling at the situation.

The notebook has a very high level of password encryption.

This middle-aged man can talk for half an hour straight; isn't he a bit too confident?
"His name is Chen Yanqiu..."

Old Cat seemed to sense Li Aiguo's confusion, turned his head, lowered his voice, and briefly introduced the background of this cryptography expert.

Chen Yanqiu is a key member of the Black Room team and comes from Jiangnan.

Before liberation, he studied at the National Mathematics Department and later served as a professor. Because of his positive ideology, he joined the organization and was selected to work in the Black Room.

His publicly known identity is that of an ordinary researcher of literature and history at the provincial archives.

In reality, Chen Yanqiu is fluent in English, German, and Russian, and has profound expertise in number theory, permutations and combinations, classical transposition ciphers, and the Virginia cryptosystem.

He could even find the enemy's coding patterns just by intercepting scattered coded characters.

"Chen Yanqiu deciphered the top-secret telegrams in the notebook before liberation, making a great contribution."

Li Aiguo was also slightly taken aback. The great achievement that Lao Mao mentioned must be extraordinary. Could it be the one with the "Tiger Tiger Tiger"?
Li Aiguo didn't ask any questions; he just stood there watching Chen Yanqiu busy herself.

Chen Yanqiu picked up a pen and started writing and drawing, then picked up a hand-cranked calculator and seemed to be calculating something.

"What, you're a tech expert like yourself, interested in cracking codes?" Chen Yanqiu suddenly stopped writing, looked up at Li Aiguo.

"You know me?" Li Aiguo asked, somewhat surprised.

"Haha, aren't you the train driver? Last time our weather station had a big meeting, you were speaking up there, and I was down there."

“…” Li Aiguo touched his nose.

I never imagined that I would become a celebrity at the weather station without even realizing it.

Chen Yanqiu said while she was busy.

"There are many types of cryptography, such as the Virginia cipher, shift cipher, polyalphabetic substitution cipher, book key cipher, etc. There's nothing particularly difficult about this kind."

When dealing with multi-layered encryption, sometimes it takes months to get results.

It seems Chen Yanqiu has already found a way to decipher the code; no wonder she seemed so relaxed.

"Multi-layered encryption? Have you ever encountered it?"

"Don't even mention it, just last month..." Chen Yanqiu was halfway through her sentence when she suddenly seemed to remember something, looked up at the old cat, and gave him a questioning look.

Old Cat understood immediately and nodded: "Old Chen, I brought Aiguo with me this time. It was approved by Comrade Farmer."

From now on, Aiguo will have free access to and from the Black Room, and the right to access information.

Although this statement did not directly specify Li Aiguo's current position, the meaning was quite clear.

The weather station may soon be undergoing a generational change, and Li Aiguo is a key figure being groomed for leadership.

Chen Yanqiu nodded slightly, then relaxed and recounted the case from last month.

Last month, our coastal radio stations intercepted an encrypted telegram.

At first, no one took it too seriously. After all, that area was a mixed bag, with rats roaming around frequently, and intercepting garbled telegrams was a common occurrence.

The local meteorological station, following standard procedure, sent the encrypted telegram to the black room.

They initially thought the black room would be easy to crack, having accumulated a wealth of experience over the years.

The result surprised everyone: the encrypted telegram used a rare multi-layered encryption method.

"Based on my analysis, the telegram at least used nested encryption."

Li Aiguo also has some knowledge of encryption.

So-called nested encryption is actually an advanced branch of multi-layered encryption.

The principle is simple: a secret message is encrypted using multiple different encryption methods before it is sent.

Cracking it requires peeling it layer by layer, like peeling an onion; one wrong step will result in a bunch of useless code.

The difficulty of cracking nested encryption is exponentially related to the combination of encryption methods used and the number of nesting layers.

Chen Yanqiu continued, "Based on my analysis, the telegram used at least nine layers of encryption."

We can now confirm that it used shift ciphers, a custom key based on a military lexicon, multi-table substitution scrambling encryption, and random key encryption.

Upon hearing this, Li Aiguo couldn't help but gasp.

He finally understood why the Black Chamber had been unable to obtain the telegram for so long.

The encryption methods mentioned earlier are fine.

The most crucial element is the random key encryption.

The key for this encryption method is not fixed at all.

It could be a few lines from an obscure novel, the local temperature on a certain day, month, and year, or even a long string of illogical dice numbers.

The essence of cracking a code is actually finding the inherent connections between things amidst chaos.

With nine layers of encryption nested together, plus the outermost layer of defense being this illogical random key encryption... it would be extremely difficult to crack by human effort alone.

"We spent more than a month trying to come up with countless permutations and combinations, but we still couldn't figure it out."

Chen Yanqiu sighed.

When a pattern to the key cannot be found, there is actually a primitive but also the most brute-force method for cracking passwords.

That is the "exhaustive search method".

That is, try all the possible combinations, and you'll eventually find the right one.

In this era, computing power was insufficient, so it was rarely used.

Li Aiguo clearly remembered that in later generations there were brute-force cracking programs specifically designed for various cryptographic systems.

If we could write out those algorithms and put them into a supercomputer for brute-force computation, we might actually achieve something amazing!

Just as Li Aiguo was about to make a suggestion, Chen Yanqiu suddenly stopped what she was doing and then let out a long sigh.

"Alright, this secret letter is done."

As he spoke, he copied the final deciphered text onto a piece of white paper.

The letter was surprisingly brief, consisting of only one sentence.

However, when the old cat leaned closer to see the sentence clearly, his expression changed drastically.

"Get the complete set of blueprints for the high-speed Eastern-type electric train!"

"Train driver, we're in big trouble now." Old Cat suddenly turned to look at Li Aiguo.

The high-speed Oriental-type electric train has already received a large number of orders and will definitely be a major source of foreign exchange earnings in the future.

Dieter's intention to take action instantly escalated the severity of the situation.

The old cat immediately reported to the farmer.

"I never expected that the higher-ups would specifically praise the outstanding contributions of the high-speed Eastern electric train at the meeting just now. These rats have already set their sights on us so quickly."

After listening to the report, the farmer looked at Li Aiguo and said, "Aiguo, you designed this train. You will be the leader of the investigation team this time. You must protect the blueprints and find Dieter out."

"Yes, sir! I guarantee I will complete the mission!" Li Aiguo straightened his back, stood at attention, and saluted.

A temporary investigation team was quickly formed.

Li Aiguo served as the group leader, Lao Mao as the deputy group leader, and several other familiar faces served as group members.

Because it involved encrypted telegrams, Chen Yanqiu also joined the project, specifically responsible for cryptographic work.

At the first case analysis meeting, all the members of the investigation team looked serious.

Although they've cracked the coded message and figured out the other party's intentions, they have no leads. Finding Dieter is like searching for a needle in a haystack. "Aiguo, what's your opinion?" Old Cat looked around, and seeing that none of the team members seemed inclined to speak, turned to Li Aiguo.

Li Aiguo stood up and said, "Before we discuss how to catch the rats, let me first introduce the current state of secrecy regarding our electric train blueprints."

Li Aiguo is now a seasoned veteran, and he took precautions to keep the development of the high-speed Dongfang-type electric train a secret.

The train's overall layout, electrical control schematics, traction transformer system, car body structure, braking system, VVVF frequency converter, pantograph, and other core components were all disassembled and broken down.

Besides Li Aiguo, even Chief Engineer Liao didn't know the complete master plan.

Furthermore, there were no blueprints stored in a centralized location.

Each technician is only allowed to view the partial machining drawings of the section they are responsible for.

As for the manufacturing of precision components, especially the motor part, it was handled by the Qianmen Locomotive Depot workshop, so the possibility of leakage was almost zero.

"So, Dieter has definitely returned empty-handed this time?"

After listening to Li Aiguo's introduction, the group members all breathed a sigh of relief.

As expected of a veteran security officer, Li Aiguo has thought of everything he could think of.

Li Aiguo frowned: "Things are definitely not that simple. This time, the enemy went so far as to send a delegation in as a cover for the blueprints, and even used such a high-level secret message..."

Li Aiguo turned to look at Chen Yanqiu beside him.

“That coded telegram was much more complex than ordinary military coded telegrams, and I could smell the Mei Agency’s influence in it.” Chen Yanqiu nodded.

"That's right, it is indeed the Mei Agency. Before liberation, I had dealings with them and witnessed their methods."

Although they changed the encryption combination this time, their preference for random character arrangement remains the same.

Many cryptographers working on top-level encryption, much like artists, unconsciously leave their own personal preferences, much like a signature.

This is why Li Aiguo asked Chen Yanqiu to join the group.

Conducting a survey requires collaboration among multiple parties.

As a top cryptography expert, Chen Yanqiu was able to provide them with clues from a cryptographic perspective.

Upon hearing this, the investigators' expressions changed.

Li Aiguo continued, "The fact that the other side has gone to such great lengths this time clearly shows that they came prepared."

Since they dared to send a secret message claiming to have "obtained the complete set of blueprints," perhaps... they've discovered a loophole in our defenses that we ourselves haven't even noticed!

Old Cat took a deep drag on his cigarette, stubbed it out, and spoke in a low voice.

"I agree with Comrade Patriot's judgment!"
The confidentiality regulations devised by the patriotic comrade were theoretically flawless.

However, any system ultimately needs 'people' to implement it!
Everyone makes mistakes.

"I think we can't just sit here and wait to die; we must move into the Changxindian Locomotive Factory as soon as possible!"

This is what a veteran investigator is all about.

The old cat instantly grasped the essence of the problem through the surface.

In the entire train production chain, the only entity that could potentially leak large-scale technical details is the Changxindian Locomotive Factory, which is responsible for mass production.

"Okay, it's settled then!" Li Aiguo made the final decision.

"It's getting late today, Comrade Lao Mao. You need to immediately contact the security department of Changxindian Locomotive Factory and make a secret connection."

Tomorrow morning, our entire team will officially move into the factory area and begin a covert investigation!

"Yes!" everyone answered in unison.

After the meeting, the team members dispersed to prepare the necessary documents and equipment for tomorrow's operation.

Li Aiguo chatted with Chen Yanqiu for a while longer.

This old cryptography expert was highly skilled and had unique insights into cryptography. Li Aiguo learned a lot about the application of compiling and decryption programs.

Chen Yanqiu felt that this young man was quite quick-witted. He clearly didn't have much of a foundation in decryption, but after a few words, he could always come up with some forward-thinking theories.

For example, the most effective way to crack a secret telegram is actually through exhaustive search.

"Comrade train driver, those of us who work in cryptography know this, but even the simplest 10-bit key has tens of thousands of combinations in theory, and it is simply impossible to try them all by manpower."

Li Aiguo smiled and said, "What if we don't rely on manpower?"

"If not manpower, then what?" Chen Yanqiu asked in surprise.

"I plan to develop a decryption program and use a supercomputer to crack coded messages in the future."

Li Aiguo's earth-shattering remark left Chen Yanqiu speechless for a long time.

This young man... he's completely unpredictable!
Using supercomputers to solve passwords?
However, upon closer reflection, Chen Yanqiu's expression became more serious.

Currently, some of our overseas counterparts are already researching the use of computers to decrypt electronic data, but the results have not been very good.

Li Aiguo is a computer expert; he might actually have a solution.

"Comrade train driver, if you ever develop a program to crack coded messages, be sure to include me."

Chen Yanqiu also knew that the most important task now was to capture those Dieters.

"Of course, if we really want to work on the program, we absolutely need your professional guidance, Professor." Li Aiguo agreed with a smile.

It was nearly evening when Li Aiguo left the weather station.

Originally planning to go straight back to the courtyard house, but considering Dieter's situation, Li Aiguo rode his motorcycle to the Changxindian Motorcycle Factory.

The locomotive factory was quiet; the first batch of electric trains had already begun manufacturing.

The technicians were divided into several groups, each responsible for a specific part.

Li Aiguo chatted with Chief Engineer Liao for a while, and finding nothing unusual, he decided to leave.

Just as I got on my motorcycle, I saw Chen Xingyi coming out of the cafeteria carrying an aluminum lunchbox.

"Hey, brother-in-law, off work?" Chen Xingyi heard the sound of the motorcycle, looked up, and quickly walked over to greet him.

"What's wrong? Judging from your posture, you're going to have to work overtime at the factory tonight?" Li Aiguo asked, looking at the lunchbox in his hand.

"Yes, electric trains are now in mass production, and the workshops are operating on three shifts. We technicians have to be in each workshop to keep an eye on things," Chen Xingyi replied.

Upon hearing about work-related matters, Li Aiguo took out a pack of sunflower cigarettes from his pocket and handed one to Chen Xingyi.

How's things in the workshop right now?

"Just as you stipulated, each workshop is responsible for different processes, each worker group is responsible for different parts, and the same goes for the technicians. Take me for example, I am mainly responsible for the bow and fire protection system."

Hearing this, Li Aiguo was filled with doubt.

Since Changxindian Locomotive Factory is producing in accordance with regulations, how exactly will the other party proceed?
So, the other party was determined to get the complete set of blueprints.

Where should we start to find a breakthrough?
Or am I just overthinking things?

Or is the enemy actually using a feint?

Li Aiguo was too lazy to dwell on things he couldn't understand. Anyway, the undercover investigation team would be moving in tomorrow, and the fox would eventually show its tail.

After chatting with Chen Xingyi for a few more minutes, Li Aiguo started his motorcycle again and roared away from the factory area.

Chen Xingyi watched the motorcycle drive away, then turned and walked towards the main office with his aluminum lunchbox in his hand.

He has now been promoted to engineer and joined the research and development team. If he can achieve results, he may be able to advance further.

Furthermore, she won't let her brother-in-law's help go to waste.

"Engineer Chen, did you just finish eating?"

As Chen Xingyi was pondering the evening's production plan, a clear and melodious female voice suddenly reached his ears.

He subconsciously turned his head, and after seeing the slender figure walking towards him, he quickly smiled and greeted her.

"Oh, it's Comrade Zhou Ning. You just finished eating too? Why are you staying at the factory to work overtime tonight as well?"

The visitor was Zhou Ning from the Equipment and Power Department.

"There's no other way. The factory is ramping up production right now, and our Equipment and Power Department is responsible for all the equipment in the factory. We definitely have to make sure that the equipment doesn't break down." Zhou Ning brushed a stray hair behind her ear and smiled radiantly.

It must be said that Zhou Ning is indeed very beautiful.

Those big, watery eyes blinked as they looked at Chen Xingyi, with a hint of something indescribable.

She was definitely recognized as the "factory beauty" of the Changxindian Locomotive Factory.

However, Chen Xingyi was clearly a man of propriety. Seeing that Zhou Ning was getting a little too close, he immediately turned his head away without making a sound and created a slight distance between them.

There were quite a few rumors circulating in the factory about this Comrade Zhou Ning.

Although she is beautiful, I've heard that she's a bit...unscrupulous in her conduct.

It is said that he has dated many outstanding young workers and the children of workshop leaders, and his reputation is not very good. However, for some reason, he has never caused any trouble.

The factory leaders seemed to know nothing about it, and they didn't even have a basic conversation with them.

However, Chen Xingyi didn't pay much attention to these gossips.

After all, Zhou Ning is impeccable in his work; he's always available to maintain equipment, has excellent technical skills, and is very responsible.

“By the way, Engineer Chen,” Zhou Ning seemed oblivious to Chen Xingyi’s growing distance, and stepped forward to make the suggestion in a very natural manner.

"The maintenance work in your workshop was delayed during the day because of rushing to meet the production schedule."

I reckon everyone's eating in the cafeteria right now, and the night shift hasn't started yet.

"How about... we take advantage of this free time and get that machine fixed?"

"Okay, let's go then, but the new regulations are in effect now."

According to regulations, I must be present to supervise you during maintenance.

Furthermore, all replaced parts must be inspected before being sent directly to the logistics department for disposal.

Chen Xingyi put the lunchbox on the shelf and walked quickly toward the workshop.

"Of course, it's the factory's rule, how could I not follow it?"

Zhou Ning cheerfully agreed, but as she stood there watching Chen Xingyi's retreating figure, her smiling face instantly turned cold.

She narrowed her beautiful eyes slightly, then quickly composed herself and hurried after him.

(End of this chapter)