Sunday 20 March 2022

The Cipher - chapter 1 (short story)

chapter 2  | chapter 3 | chapter 4


Cassie, Anna, Jake, and Phil were in the university canteen having some fruit juice. The exams were over, and the four of them had spent the entire day shopping. Okay, it was window shopping mostly, but Cassie had really enjoyed herself.

Anna and Jake were third year electronics engineering students like Cassie. Phil was a computer science student, but he knew them from first year classes and the four had bonded instantly over common interests.

“So, let’s go our own way, then?” asked Anna.

Phil yawned. “Yup. Need nap. Brain not functioning anymore.”

“Um, actually, there’s something I wanted to talk to you about,” said Jake.

Cassie blinked. Was Jake actually being serious? What was going to happen next, the complete reversal of gravity?

“You’re good at ciphers, right, Cassie?”

“Maybe? I suspect Phil knows a bit about them too.”

“I’m average,” said Phil.

“Anyways, I need you two to decode something for me. You have nothing pressing at the moment, I assume?”

“Other than stuff I’m basically tinkering with, no,” said Phil.

“I’m not too busy either,” said Cassie.

“Okay, so my girlfriend has been sending some random texts. It definitely means something to her. I saw the messages and asked her about it, and she forwarded it to my phone at once. The thing is, the damn thing’s in a cipher of some sort. I can’t make head or tail of it.”

“A normal person would just ask their girlfriend, you know,” said Anna.

Cassie nodded.

“Apparently it’s a secret but I’m free to decode it if I can. So basically, it’s a challenge. The problem, as you are aware, is the fact that I have absolutely no idea how to crack a cipher. I mean, I could learn, but this doesn’t look like the kind of thing you can crack with a two day crash course.”

“So, what’s the cipher?” asked Cassie.

“I’ll forward it to you. I’ll give you moral support, but I’m letting you know in advance that I am terrible at…”

Phil yawned. “Just forward the damn thing.” 

“Okay.”

He forwarded a message to Cassie.

acbb87bc41b48b4dbc5f9b5716a7199a0959422a802f11b27a98a5d4ff06451afe6d26b68e5d7d2cac34ce32061b744893602e363a31d0a2018dc136ef39515da7826548327b

8fc83ebc51c12828a958aba9c26561a780e7e832a1988d64987d807a489fd2bbd123457e85e2f159685a4be44939c92ee970608b64b347fe17d1c1d3113b37a007edfb51368054c5c3c2da3be8eed0a2cbe

ca5c634da7451865d5a41c08d7968fb67b41652a3a44920f1c7e4f979f1dc23c8e0db94b6e89b00cf8a42d11b514d073e5570e65d240a70c87041f6752ce4e11b6b59f221e55b1a1651d

Cassie stared at it. It looked more like a list of numbers than actual ciphered text.

“It’s hexadecimal,” said Phil.

Jake shot him a blank look.

“You know, hexadecimal. Base 16? How did you submit you embedded programming assignment without it?”

“Y-yeah, I know, I just feel a little stupid. I should have realised that.”

“Is this an assignment or something then?” asked Cassie.

“Nah, we don’t have any assignments due right now,” said Phil, “Dany’s taking an elective that I’m not doing, but I don’t think they’d deal with strings of hexadecimal numbers.”

Cassie knew Dany – Jake’s girlfriend – as well, but they weren't really friends. She was generally a bit loud, but pleasant to be around. She was a computer science student like Phil.

“Are you sure this is a cipher?” asked Phil.

Jake shrugged. “Dany said so.”

“Anyway, we’ll work on this independently and share notes, say, tomorrow? Or just text?”

“Just email it if you get the solution,” said Phil, “I mean, you’re going to have to crack that thing on a computer and email's more convenient. I’m going to start work on it after my nap. See you later then!”

Phil left. Cassie, too, left for her dorm room. She tried staring at the numbers a few times as she walked. The obvious first solution was ASCII in hexadecimal. It would be super easy to convert, because of the sheer number of online converters.

Cassie took her phone out and looked at the numbers again. Then it clicked. It couldn’t be ASCII. This wasn’t Cassie’s strong suite, but she did remember that ASCII used 7 binary digits. Ergo, it could go from 00000000 to 01111111 in binary. That would be 0-127, or in hexadecimal, 0 to 7F. Therefore, if it was ASCII, every letter in the 0th, 2nd, 4th, etc position would have to be 7 or less. That was obviously not true, as the very first character in the cipher was A, or 10.

Of course, the person who made this cipher could be insane enough to just string the seven-bit numbers end to end. Would that leave a tell? She would have to check that once she returned to her dorm room.

She reached her room. She showered, had more snacks, and finally opened her laptop. She decided to have a go at the cipher for a bit. She started it up.

The computer took a bit of time to start. In the meantime, Cassie tried thinking through the problem again. Surely, the most important thing to figure out would be the identity of the creator of the cipher. Their personality would give them a clue about it.

Another thing to consider would be purpose. Could it be criminal? Unlikely. Dany wasn’t the criminal type as far as Cassie knew, and it would make no sense to hand over the cipher to Jake if it involved anything criminal. Jake didn’t have the patience to crack a cipher, but to assume it would be safe with him was foolish. He was friends with Phil, and Phil was really good with computers. He would surely crack it.

Another possibility was that this was enciphered with something like the regular encryption used for data transmission and stuff. Cassie didn’t know too much about it, but she knew for sure that that they involved long keys that would be near impossible to bruteforce. Guessing it would be out of the question.

In the first place, would Dany be able to pull off something like that? Cassie knew the answer immediately. Dany was smart and good at maths. If she understood the theory, she could program it manually even if she didn't have access to a dedicated program for the job.

If that was the case, there was no way they were cracking the code. Dany would have realised that. This could still be a criminal matter.

If not, the code would still be hard to crack, but it would be doable.

What would she do if the code was impossible to crack? Could she hand over the code to law enforcement? It wasn’t like Cassie knew a lot about how law enforcement really worked in the first place. But if it came down to that, could she do that? She would be betraying Jake’s trust. She would be betraying Dany’s confidence in Jake. But hiding a criminal matter could cause more harm in the long run. People were capable of becoming generally worse, especially with no feedback telling them that that was the case. Besides, Cassie, who had never broken a law in her life, would be aiding and abetting a criminal.

The computer finished booting up. Cassie let out a deep sigh. She didn’t know whether the code was breakable yet. She had to figure out that first. If it wasn’t, well, she could worry about it later.



END OF CHAPTER ONE


Thank you for reading! Do let me know if you manage to crack the cipher (hint: It doesn't require a key). 

Read next chapter: chapter 2  |  chapter 3 | chapter 4

You can also follow me on Facebook here.

Until next time!

 

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