Waterloo’s winter weather was so fickle it was impossible to predict.
Cold air descending from the Arctic met the Great Lakes and transformed into clouds heavy with snow. It was common for roads that had been perfectly fine the day before to be paralyzed under snow piled up to the waist.
People armed to the teeth in thick padded coats, gloves, and scarves trudged through the snow with accustomed expressions. Whenever Damian saw snow piled up in soft white heaps, he would often be reminded of his childhood.
“Dad!”
His own voice as a child.
On days when heavy snow made it difficult to go outside, his father would always sit at his workbench, tinkering with something. Trays filled with tiny parts, precise tools and sets of screwdrivers, and the faint smell of oil that always lingered. To Damian, that was the nostalgic scent of his father.
“What is it, my little knight?”
He turned around and asked.
A book lay open on Damian’s knees. On one side of the page was a strange machine printed in black and white. There were alphabet keys lined up like piano keys and rows of tightly packed light bulbs. The most fascinating part was the gears inside the box, turning with intricate precision.
“What’s this?”
“Ah, that?”
He looked at his son and gave a playful smile.
“It’s a cipher machine called the Enigma. The German army used it during World War II…”
He stopped speaking, then lowered his posture. And as if sharing a secret, he whispered in a low voice.
“This was the hardest cipher in the world to crack. People believed messages made with this machine could never be deciphered.”
Young Damian’s eyes grew round.
“Never?”
“Yes, back then.”
Damian could not take his eyes off the photograph.
His father chuckled, took out a sheet of paper, and began drawing simple lines.
“Now, look. The principle is very simple.”
By modern standards, the Enigma was nothing more than a machine with an ordinary switch structure.
But interpreting 150 million times one million—roughly 150 trillion—possible combinations without the help of a computer was impossible with the technology of the time.
“Then who deciphered it?”
“That’s the most interesting part. There was a man named Alan Turing…”
In an instant, he was drawn into the story his father told him.
That was the moment Damian became captivated by the labyrinth called cryptography. The year he turned ten, with the help of his engineer father, he built a device that improved upon the Enigma’s weakness.
Click.
He pressed a button on the box sitting on the desk.
With the sound of gears turning, a small bulb lit up.
Whirrr—
The original Enigma had a fixed reflector. Because of that, there was exactly one thing it could not do. It could not return to itself. An absolute rule had been created: no matter what letter was pressed, that same letter could never come out.
Turing dug into that tiny gap and brought the Enigma down.
Whirr, whirr—
Even as the years passed, ciphers remained the game he loved most.
Even technology once called the absolute shield of an era would reveal flaws with time. Someone would dig into that opening, and someone else would create a device to patch it. Like an endless chase that would never end. And from childhood, the dream he had held was to become the final victor of that thrilling game.
“There are no flaws in Kyber.”
Damian muttered as he watched the winding mechanism turn.
Knock, knock!
“Come in.”
“Am I interrupting?”
“No.”
The professor looked down for a moment at the improved Enigma on the desk, then pulled over a chair and sat in front of him.
Damian’s gaze turned to the newspaper in the professor’s hand.
[Team Apex, Which Solved the Riemann Hypothesis, Heads to Korea with Yu Seoha. Reportedly to Research Next-Generation Post-Quantum Cryptography]
Damian’s eyes narrowed.
“It looks like MIT has made its move. I thought they weren’t very interested in cryptography.”
“I suppose the rumors were true.”
Anyone who studied mathematics had a copy of Yu Seoha’s paper on the Riemann hypothesis.
An extremely difficult paper. But precisely because of that, it set one’s spirit of challenge ablaze. It was perhaps similar to the reason mountaineers went all the way to Nepal just to climb the Himalayas.
Even in Waterloo’s mathematics department, students could often be seen highlighting Seoha’s paper. Not the parts they understood, but the lines they hoped to understand someday.
“Aren’t you worried?”
Tap, tap, tap—
Instead of answering, Damian lightly pressed the keys of the Enigma on the desk. A bulb flickered, displaying an encrypted message.
[NO PROBLEM]
“Yu Seoha’s paper is incredibly beautiful. I could feel a tendency to pursue order almost obsessively. But cryptography is not that kind of world.”
As if agreeing with Damian’s words, he nodded.
Professor Michele was a renowned mathematician and the designer of SIKE. SIKE was an isogeny-based cryptosystem, characterized by overwhelming efficiency and an elegant mathematical structure compared to other PQC candidates. Ironically, that was also the reason Damian had been able to bring SIKE down.
To solve SIKE’s maze, one had to find a path through multidimensional space. But Damian used an auxiliary theorem to lift the problem into a higher dimension, then unfolded the complicated maze into a straight line.
A problem that was said to require hundreds of years to solve even with tens of thousands of CPU cores had been reduced, through outstanding mathematical intuition, to the computational workload of a single home laptop.
‘What a pity. Truly, what a waste of talent.’
What if he had not fallen in love with the Enigma as a child?
What if he had played with the four color theorem like Yu Seoha?
Perhaps the mathematical world might have possessed two great intellects at the same time. Like Newton and Leibniz.
But Damian’s interest lay solely in cryptography. The only reason he had studied mathematics was that it was necessary to create more efficient and powerful ciphers.
Yet even with that alone, Damian was brilliant enough to rival the greatest mathematicians of this age. Yu Seoha’s paper, which had taken most reviewers weeks to read in full, Damian had devoured in three days.
“In essence, the more mathematically perfect a cryptosystem is, the weaker it becomes. Its logical cause-and-effect relationships are clear, so they can serve as signposts for an attacker as well.
People who value mathematical order cannot escape the temptation of linearity. I’m sure you know that very well, Professor.”
Professor Michele gave a bitter smile.
Perfect linearity and symmetry, the integrity of logic that allowed no rebuttal. Seoha’s mathematics was too beautiful. And for precisely the same reason, it would be broken.
“I intend to break the cipher he creates with everything I have. When that happens, he will understand too. That in this world, there exists a void that can never be calculated.”
The professor looked puzzled.
“Is there a need to go that far? Focusing on Kyber should be enough.”
Damian spoke with a mischievous smile.
“I will return a genius to the place where he truly belongs. I believe this is how I can contribute to the world as a cryptographer.”
* * *
Near the low foothills on the outskirts of Daejeon, there was a building surrounded by heavy security personnel.
It was a building originally designed as a secure facility for the Agency for Defense Development. But just before completion, its sign was suddenly changed.
[Apex Lab KOREA]
“Wow, it really feels like a military facility. So this is where Seoha is ‘serving.’”
Its exterior called to mind a secret research facility.
Cecilia, carrying a large moving box, gazed at the outer wall of the building in admiration. Behind her, Theo, Sujeong, Sri, and Ben were busy taking care of their own equipment.
They would be living together in a detached house in downtown Daejeon. Morris, the butler of the Ashley family, had arrived in Korea early and was already preparing the space where the head of the family would stay.
Pshooong—
As the heavy security door rose, the interior of the lab came into view.
As requested, it looked as though the Apex Lab at MIT had been moved here exactly as it was—no, a cutting-edge facility on a far larger scale revealed its imposing presence.
“It’s a state-of-the-art server!”
Sri’s eyes sparkled as he ran toward the server rack in the center of the main hall.
After briefly touring the lab, the team members headed to the conference room. There, all the personnel from both Korea and the United States who had been waiting for them had gathered.
‘So those people are Team Apex…’
‘They look too young.’
‘He really has red hair. Wow! He’s way more handsome than in the photos.’
‘Why are they all so good-looking? I heard a rumor they consider looks in the test too. Was that true?’
‘The countess is beautiful. Sujeong has grown up well too.’
In the eyes of those wearing crisply ironed white coats, tension and anticipation could be seen at the same time.
The Korean government intended to use this opportunity to create as broad a field of exchange as possible.
When a recruitment notice was posted for collaboration with Team Apex, the Korean scientific community was turned upside down. A team that had proven one of the great problems of the century. Who would not want a place here? These were elites selected after overcoming a competition rate of more than one hundred to one.
Gulp.
Among them was teaching assistant Park Hyeongju, the self-proclaimed genius of Nowon-gu.
As a cryptography specialist, how could he let such a once-in-a-lifetime opportunity pass by? Professor Kim Jiyun had also readily given her permission.
‘Who’s the rumored supporter?’
Aside from Seoha, there were many rumors surrounding the members of Team Apex.
For example, it was said that Theodore Lanford, the lab’s number two, looked down on anyone who failed to meet his standards as if they were trash.
There were also rumors that Sujeong’s main job was actually making coffee, and that Srinivasa Krishnan was a cold-blooded man who cared only about money.
And then there was the problematic supporter, or utility man.
Hyeongju’s gaze turned toward Ben.
He had heard that Ben was the only person in the lab who had entered without taking the test. The accepted theory was that it was thanks to his exceptional ability to clean up after others.
In the past, he had apparently been a fairly well-known gifted student, but now he was a fixer who cleaned up the messes the team members made. So it was only natural that everyone would think this.
‘Couldn’t I get in by pushing him out?’
‘If it’s cleaning up after people, I’m no slouch either.’
Ben grasped the meaning of the gazes directed at him and gave a crooked smile.
Theo checked his watch, then stepped forward.
“Nice to meet you. I’m Theodore Lanford. Our team does not specialize in cryptography, so we lack experience. We look forward to learning a great deal from all of you.”
At the greeting, far humbler than expected, smiles spread across everyone’s faces. But at the words that followed, the conference room fell into silence.
“So please pass on all the knowledge you have to us within the next four weeks.”
It was a declaration that they would absorb everything from the basics of cryptography to modern post-quantum cryptography in just one month.
The team members stood beside him with expressions that said this was only natural. It was a remark born from their many experiences studying other fields alongside Seoha, but it was true that it lacked consideration.
‘That’s way too arrogant.’
‘They should say something that makes sense.’
An unmistakable intellectual arrogance could be glimpsed from them. The researchers quietly gritted their teeth one by one.
‘Try it if you can.’
‘You think you can look down on cryptography just because you’ve had a little success? I’ll have you crying your eyes out in a few days.’
And so the first seminar began.
Hyeongju stood in front of the whiteboard. In truth, he had complicated feelings in his heart. Excitement at working with the stars of the mathematical world, but on the other hand, a desire to show them what was what.
He shook his head roughly.
‘This is an opportunity. Let’s do this properly.’
Hyeongju resolved to show them the essence of cryptography. However…
“Uh, hmm. The Gaussian noise distribution is a little too honest. Compared to the random numbers we used to handle, it’s too easy.”
“If we twist the tail of the distribution with this equation, an attacker won’t be able to probabilistically predict the path, will they? I’m thinking of applying an infinite series. Would you like to take a look?”
“About that threshold setting method—let’s apply the nonlinear method we made before in minimum energy theory. Ben, do it right away.”
The complexions of the Korean and American elites gathered in the conference room turned pale.
It was not surprising.
After all, cryptography was merely a spice added atop the enormous mathematical foundation they already possessed.
Hyeongju had prepared dozens of pages of materials to explain the difficulty of lattice-based cryptography, but Team Apex had already reached beyond the conclusion before he had even finished writing out the equations.
“Please hurry. We don’t have time.”
“What?”
At Theo’s urging, Hyeongju wore a blank expression.
“Seoha is coming. In four weeks! We need to build up as much as we can before then. Once Seoha starts designing the cipher, it’ll be hard to keep up, you know?”
“If it looks like we don’t understand, he stares at us while blinking like a deer.”
“That’s right! That expression that says, ‘Huh? Why don’t you even know this?’”
“I don’t want that face turned toward me. Everyone, faster—more!”
They, too, were all desperate.