The next morning.
Uhyeon arrived at the office two hours later than usual. His assistant held out a smartphone along with coffee. On the screen, headline articles from various portal sites were displayed.
[Shin Uhyeon, The Mad 8-Hour EBS Lecture on the Riemann Hypothesis]
[Why Did the Top-Ranked Instructor Shed Tears?]
[Yu Seoha's Chat Verification Goes Viral: "Shin Uhyeon Is My Teacher."]
"Sir, interview requests are pouring in. There are five broadcasting stations alone, and I gave up trying to count the internet media outlets. There are also offers for talk shows and educational programs."
Uhyeon glanced at the screen and shook his head.
"Reject them all."
The assistant asked back with a startled expression.
"All of them?"
"Yes. Cancel the meeting this afternoon too."
"Excuse me?"
Uhyeon hurried into his office.
The assistant didn't ask any further.
Because she knew he never went back on a decision once made. Uhyeon went into his office and lowered the blinds.
Thud, thud.
He walked to the inner corner and pulled out a box thickly covered in dust from deep within a cabinet. Then he swallowed hard and slowly opened it.
Swish.
What came out from inside was a thick stack of papers.
It was his unfinished thesis that he had been researching before leaving graduate school. It was so old that the cover had yellowed, and coffee stains had seeped in here and there.
That which had once earned him the label of Princeton's rising star, and which he had ultimately failed to complete, stuffing it into his bag before returning.
He couldn't bring himself to throw it away. But he hadn't wanted to see it either. So he hadn't kept it at home, instead stashing it in a corner of the office.
Because every time he saw it, his heart ached as though being pierced by an awl. But now, things were different.
Flutter.
He slowly turned the pages.
The sharp handwriting of his youth filled the papers.
'This was where I was stuck.'
Around page 20, question marks were dotted one after another in the margins. Below them, traces of attempted approaches that had been erased were visible. At these traces showing how lost he had been back then, Uhyeon let out a bitter smile.
Scratch, scratch.
The things he had built up while wrestling with Seoha's thesis for two months flowed from his fingertips. Viewing the thesis through the language of Yu-Riemann geometry, the blocked point from over a decade ago looked completely different. Uhyeon leaned back in his chair, resting his body against it.
'Strange.'
It wasn't painful. Rather, an energy surged from within—a feeling that he could do something.
Torn and crumpled paper. He had carefully taped it back together. It was tormenting, as if it showed his despairing self from that time without filter. But unlike before, it was bearable.
'What am I doing, at this age...?'
But he couldn't suppress his curiosity. At the very least, he wanted to know what lay beyond this.
'Had those struggles truly been meaningful?'
Uhyeon picked up a pencil. And beside the question mark, he slowly began to expand the formula.
One line, two lines.
His hand moved faster. The coffee had gone cold.
Knock, knock!
"Sir, what would you like to do for lunch?"
"......."
There was no answer.
The assistant sensed something odd and cracked the door open. Several sheets of paper were scattered across the office floor. Uhyeon sat hunched over his desk, writing something. A face completely different from his usual self—it wasn't the look of someone mechanically cranking out problems.
Creak.
The assistant quietly closed the door and left.
***
[Regular Report]
To: David, Chief Researcher, NSA
-It has been three months since I came to Korea. Korea is quite a pleasant country to live in. The cafeteria serves surprisingly healthy and delicious food every day. I want to return to my hometown soon, but I think I'll miss this cafeteria terribly.
Lately, there have been some unusual points regarding Seoha's movements.
It's not in the report, but he seems to be seen playing the piano often. His skills are better than expected, so I was
surprised too.
The cipher development experienced considerable chaos in the early stages.
It was only natural. What researcher could graciously accept being told to redesign everything from scratch? There were also practical reasons.
Not many people properly understood Yu-Riemann geometry. Seoha didn't force the matter. He merely said this.
"Then couldn't you all take on the role of the Red Team?"
Honestly, I was quite offended.
Being excluded from cipher design and assigned to attack was a slight against us, no matter how plausible the reason sounded.
A senior researcher on the Korean side raised his hand and asked.
"What happens if we break through?"
Seoha hesitated for a moment before answering like this.
"Would you tell me what you wish for? I'll do my best to reflect it within my abilities."
The researchers exchanged glances and spoke up one by one.
"Even asking to be accepted as a member of Apex Lab?"
"Once your three-year service ends, you'll return to America. We want to move with you then."
I suppose everyone felt the same way. This is certainly an attractive workplace. The guaranteed career prospects are probably the biggest factor.
Seoha seemed flustered, but Teo beside him smiled and said.
"A talent capable of breaking the cipher Seoha created—I would certainly love to work with you formally."
But the faces of team members like Sujeong and Ben were peculiar. Expressions asking why they would entertain such useless thoughts? They seemed to believe such a thing would absolutely never happen.
The amazing part is here.
Seoha disclosed all the algorithms of the cipher he and his team members had designed together. What he said was a masterpiece.
"If you want to break through, you must first understand it."
David.
It took us a week to understand the principles of this cipher. And we are cryptographers.
In Yu-Riemann geometry, space is laid upon the operations of a non-abelian group. Each time the curvature changes, the operational path changes, and when the path changes, the geodesic—that is, the shortest path in this space—changes as well.
No matter which path the attacker chooses, that path leads to a space of different curvature, where yet another non-abelian operation awaits.
It's like a maze whose structure changes with every step, giving me a chilling feeling. Still, I think I've found a bit of a clue, so I'm looking forward to it. I'll contact you again soon.
P.S.: I'm not sure if Ruka is really a trustworthy agent. I saw him cornering Srinivasa and asking in detail about Apex Lab's benefits and salary.
***
[Tier Zero and Cipher Development Trends Report]
To: David, Chief Researcher, NSA
-David, it's been a while. Quite some time has passed since my last report. I'd like to use busyness as an excuse, but the truth is closer to not knowing what to write.
You're asking what happened?
It started when Seoha set up a computer in the lobby. The cipher was displayed on the screen. There was a memo stuck below the monitor.
[I will offer a contract to whoever breaks it first. You may form teams.]
It was in Seoha's handwriting.
David, everyone took out their phones and photographed it for evidence.
The next day, teams formed. They were mostly groups composed of cryptography majors, engineers, and geometry specialists. I'm on a team too, of course.
The research center is a complete madhouse right now.
The lobby has become an operations room. When I come in in the morning, the floor is covered with sleeping bags and empty coffee cups. I told you last time that I'd found a clue? Forget about that.
The cipher is updated every week. It reflects the patterns of attackers studied in real-time. It seems to mean that our work also holds meaning in its own way, which is reassuring.
The research center is full of vitality now.
Each team takes out their own weapons and attacks the cipher with everything they have. We used to barely exchange greetings, but now when we run into each other in the hallways, we smile while keeping each other in check. It's fun to probe other teams' progress while eating in the cafeteria.
It's a competition, yet strangely enjoyable—probably because of what Seoha said.
"Are you worried the cipher will really be broken? Not at all. It is the fate of a cipher to be attacked. If you break it, it is your victory; if it remains unbroken, then is that not a victory for everyone?
After all, that would mean the research center has fulfilled its purpose."
I think I finally understand why he asked us to take on the Red Team.
David, his cipher is a predator that feeds on the intelligence of its attackers. With every weekly update, its weaknesses disappear.
What's even more amazing is that we, watching this process, feel not displeasure but a sense of accomplishment.
Ah! I just came up with a good idea to bypass the cipher. I'll end here.
***
"Seoha, you really are..."
Teo let out an admiring sigh as he observed the situation in the lobby. Leading cryptographers from both Korea and the United States were throwing themselves full force at the cipher Seoha had created.
"I was shocked when I heard there was a spy......."
Sujeong clicked her tongue.
Not long ago, Seoha had received a tip from the National Intelligence Service. Intelligence that there were spies among some of the American personnel and even among the Korean researchers.
Teo had argued that they should all be fired immediately. But Seoha tilted his head.
"Wasn't our goal to create a cipher that could never be broken?"
Instead, he disclosed all information. So that espionage would become meaningless.
"Kerckhoffs's principle."
The argument that a cryptosystem should remain secure even if everything except the key is public. In modern cryptography, there are many attempts to hide algorithms, but Seoha didn't like this.
"Thanks to that, we've been able to experience attacks devised with full force by top-tier resources. The creativity of cryptographers is truly amazing. It was exactly what we needed, with our lack of experience."
Teo snickered.
"Let's stop saying we lack experience now."
It was true that Team Apex had been amateurs in cryptography. But that was months ago. Now, they were anything but. They had been forged in an environment where top-level cryptographers unleashed new attacks every day.
"I never imagined they'd approach from outside mathematics."
Sujeong said, shaking her head.
Thanks to that, they learned something. That no matter how mathematically perfect a cipher is, the moment it is implemented in a computer, physical constraints arise.
Operation time, core occupancy, memory usage, power consumption. Joseph's team tried to find a path by analyzing the patterns in how these changed minutely.
It was a primitive approach, like listening to the vibrations when turning a safe's dial with a stethoscope. But it was effective. Thanks to that, Seoha's cipher grew even more robust.
"I think everyone has given up now."
Cecilia looked outside.
On the lobby whiteboard, instead of strategies to break the cipher, it was covered with traces of discussions to interpret Seoha's formulas and algorithms.
"It's not giving up. Look at their faces."
At Ben's words, everyone turned their gazes.
"They look happy."
"They do."
"Really?"
The sight of teams keeping each other in check had disappeared.
Now everyone had gathered in one place, looking at the same formulas. If someone explained, someone else would immediately jump in, leading to lively discussion.
"Because they are people who love ciphers."
Teo nodded.
"Ahh! I think I get it. There's no noise in Seoha's cipher. Structurally beautiful, and—"
"But incredibly efficient while simultaneously strong in security."
Sujeong added.
"So how could they not fall in love with it? It's the kind of system they'd only dreamed of."
Ben felt he could understand their feelings.
"Seoha, have you decided on a name for the cipher, by the way?"
Seoha, who had been thinking for a moment, smiled and nodded.
"I just decided. How about 'Utopia'? In the sense that mathematics can make everyone happy."
"Hahaha!"
The team members all laughed.
An innocent idea so typical of Seoha.
But to them, Seoha's words sounded like this:
"Stop your meaningless efforts to solve this cipher. It's impossible anyway. If you give up, everyone can be happy."