Edmund’s smile was so charming. I had zero resistance against it.
I spent an entire week on that slip of paper, sitting in the library with a pastry in my mouth. I try reading it upside down, downside up, forwards, backwards, and sidewards, but it still looked like the same old piece of scratch paper with stars and moons. It drove me absolutely nuts.
I remembered living in an apartment in London when I was young. During the winter nights, my parents would always sit next to the fireplace performing calculations on their notepads, just as other parents would read newspapers in front of the warm fire. Then, one day they suddenly sent me to my uncle’s farm in Bedford, along with several boxes of notes and books. Mom kissed my forehead repeatedly, promising that she would come back for me once the political climate has settled/stabilized. Dad just stroked my head, trying to comfort Mom by telling her that, since I was a big boy, I could take care of myself.
That was where I saw my parents for the last time, at the London Victoria station.
Three months later, a letter arrived at my uncle’s place from London that a fire in our apartment had killed both of them.
To be fair, uncle had taken decent care of me. Although he didn’t really parented me, he never let me starve. Maths was strictly prohibited, but the ban only made it more tempting. When I was very young, I often hid in the storage room to read my mom’s notes, huddling up against a big wooden chest, writing on the floor with half of a pencil. One day, when my uncle came to the room for an axe, he saw the entire floor covered in numbers, symbols, and equations like a swarm of wiggling earthworms. He beat me up and sent me to the local public school the next day.
In the end, I was admitted to the King’s College.
As a child, I had no idea what in my mom’s notes were called cryptography. I thought they were fascinating number-letter games. I was so intrigued and never grew tired of them.
Yes, ciphers were games. A group of people tried their best to hide something, while another group racked their brains to dig it out. If I wanted to tell you a secret, I would encrypt it with a method that only we knew, before passing it to you. When you got the message, you could recover the secret using that designated method. The information was called ciphertext after being encrypted and plaintext after being decrypted, and the method that we used was called the key.
For example, if I wanted to tell Edmund ‘I love you’, I wouldn’t write I-LOVE-YOU in plain text, but rather something like ‘hknudxnt’. The reason being, if you shifted each letter back by one place, ‘I’ would become ‘H’, ‘L’ would become ‘K’, and so on. Edmund could see this seemingly meaningless note and shift each letter forward, and thus retrieve the message. This was a classic Caesar cipher, which Caesar had used in order to pass secret orders to his generals.
In this case, since we had known the key was “shifting back by one letter”, we could easily decode the cipher. However, in most situations, the code-breakers had no access to the enemy’s key. They had to guess the method of encryption based off of the encrypted text, in order to decode it. This was exactly what I was currently trying to do by attempting to figure out the meaning of the damn piece of paper full of stars and moons.
Mathematics was inseparable from cryptography. Code-breakers were usually maths geniuses since they needed to figure out the hidden connection between tens of thousands of characters of ciphertext in order to decrypt the information.
It was said that genius cryptographers were freakishly talented mathematicians. They stepped into the field because ordinary math problems no longer intrigued them.
Edgar came to visit me in the library three times, bringing me the most recent newspapers. The Czechs wanted independence, and the Germans were planning something. So what? I only cared about my Edmund.
In the last afternoon of the weekend, the library was almost empty. The sweet scent of apple blossoms filled the air, and I sleepily laid on the oak desk. I felt someone sit down beside me, taking my notepad and flipping through the pages. I suddenly opened my eyes to see Edmund looking at me, a smile contained within his eyes.
He drew some lines on my notepad in red ink. “How did you convert the shapes into letters?”
I narrowed my eyes, leering at him from my position on the desk, frivolously said. “Babe, I will tell you if you come closer.”
Then I dragged him by his tie and leaned forward to kiss him.
In that instant, I could sense how stupefied he was, and he defenselessly allowed me to kiss him for an entire minute. The gentle spring breeze carried the smell of the privet leaves from Edmund’s shirt. Luckily, our corner was nearly empty, because the next moment, he threw me and pinned me on the desk. My wrists hurt like hell. He observed me from above with his face close to mine, carefully, for a long time, before he stood up.
WIth that same charming smile, Edmund picked up my scratch papers, tore each of them into pieces, and let them fall to the floor.
“Alan, I’ve suddenly changed my mind,” he said, “I have decided to not let you decode it.”
I had crossed the line. I pouted and stood up, trying to explain, “I sincerely like you.”
I followed after him, continuing to explain. “My dear, please allow me to explain. At first glance, those shapes do look like stars and moons, but have you noticed that some stars have three angles while others have as many as seven? Almost all the stars have a different number and degree of angles, but the shapes of the moons are identical. If each star represents a letter, it’s impossible for a sentence to contain no repeated letters. Therefore, I think it might be a modified Bacon’s cipher.”
Edmund stopped, and raised an eyebrow in interest. “Oh?”
I resumed my explanation. “In fact, the stars were only drawn in different ways to confuse us. They have no special meanings. My guess would be that the killer encrypted it like this—”
The stars represented a lowercase letter, and the moons represented uppercase letters.
First, he created his key, a modified alphabet table.
For example, three consecutive lowercase letters (‘ddd’) would represent ‘A’, two lowercase letters followed by an uppercase letter (‘ssT’) would represent ‘B’, and so on. If he wanted to write ‘AB’, he could write either ‘dddssT’ or ‘wasiuR’.
He then converted all of the lowercase letters into the different stars, and the uppercase letters into moons.
I looked into his green eyes and shrugged. “So that’s how it is, and why we only see stars and moons.”
“You have decrypted it?”
“No,” I sighed, “I managed to turn them into characters with frequency analysis, but the result was complete gibberish. I don’t know what I have done wrong.”
Edmund nodded, giving me a cautionary look. “Leave the rest to me. Alan, stop thinking about this.”
Edmund thought it was safe to just tear up that piece of paper. However, anyone would have memorized the contents if they had stared at it for seven days straight like me.
I finally stopped him in the church. The King’s College had its own church with a lofty dome. Sun shone into this empty, shadowy hall through the magnificent stained glass, painting variegated patches on the floor. He was kneeling in front of the statue of Saint Jesus. His face was pretty, his eyes were squeezed shut, his eyelashes slightly fluttering like the golden wings of a butterfly. His expression seemed painful, but he kept his body upright.
I didn’t know what his agony was about. I wanted to put my hand on his shoulder, but the moment I lifted my arm, someone grabbed me by the shoulder and threw me backwards. In an instant, I was lying on the icy floor with a harsh punch in my stomach.
We rarely saw uniformed officers in Cambridge, but the man in front of me was wearing a dark navy uniform with polished, gleaming high boots. His cap was pulled low, hiding a pair of cold, blue eyes. He looked down at me from the dominant position, but just as he was going to strike me again, Edmund grabbed his hand from behind.
“Peter, let go of him. He’s my student.” Although Edmund’s voice was soft, he somehow sounded very firm and commanding. Then, he gave me a smile, continuing, “Even though he never acts as one.”
I climbed to my feet, trying not to double over from the pain. “I want to speak with Professor Wilson alone.”
Edmund gestured to the man, who immediately left to stand at the church’s gate. I asked him, “You’re affiliated with the military service? I never knew that.”
“There are many things you don’t know.” He said with a smile, “Alan, you came at a good time. I was just going to say goodbye to you. I am leaving Cambridge for Plimpton Institute in suburban London. Don’t give me that look, I am just going to continue doing research there.”
“You work for the army.” I stared into his eyes, unable to hide the excitement in my voice. “I decrypted it. My idea was correct, but the text was encrypted three more times after the shapes were converted to letters. It was not a cipher sent by some killer to the newspaper at all—”
Edmund put a finger to his lips, motioning for me to shush.
I recited the message more fluently than any of my textbooks, “Go to London ASAP. Retrieve information on British Army’s manoeuvres on 5th from General F. Pass on to Young Eagle.” I crossed my arms, leaning against the church’s pillar. “My dear, this is a piece of military intelligence. Who is this Young Eagle?”
Edmund stared at me calmly with his jade green eyes, then sighed, “Alan, I had only wanted to test you. You shouldn’t have tempted me when I have just changed my mind.”
“I had asked you to give up decrypting out of respect for your parents.”