Cryptography: Fun with Numbers
Welcome to cryptography, the fun world of mathematical patterns ascertained from the predictable manner of language. Using some clever tricks, lots of code, and some cool software, we can crack even the hardest of codes. In this project, we are working with Khan Academies cryptography challenge 101 course to try and decipher the messages given to us.
Message #1: (Uncracked)
This code is unfamiliar, to say the least. Well, since it looks like a cipher that was made from scratch, theres nothing I can do other than frequency analysis and hope that if I can get a match, I can start to form words and letters.
This is the start of the frequency analysis, as you can see ive listed each symbol ive come across once and then write how many times they have appeared so far. Note that the letters on the bottom are not the decoded symbols, its just a way for me to list each as a variable if I want to put it into a software system. Lets continue.
Heres where I am right now, this hopefully should be good enough to start forming some digrams and trigrams and beginning to break the code.
Message #2: (cracked)
This message was pretty simple to decipher. Upon first glance, my guess was either a viginere, caesar cipher, atbash, affine etc. due to it being scrambled letters rather than numbers. So, trying from easiest to hardest, I started with brute forcing it caesar cipher style by using one of the many caesar ciphers that exist online:
If you cant see it, the first part of the code is decoded on rotation 19. The full part of that line reads: "zename blackout worried that our cipher is too weak on next message switch to vigenere cipher keyword is the hidden symbol of death in my favorite holbein end." The second part reads: "start i grabbed everything i could find please return any blueprints for vault and alarm design based on which bank you decide on i am setting up safehouse co." This is good, it tells us the type of cipher used in the next message, as well as a hint on what the key is. Overall, not bad for how easy it was to crack.
Message #3: (cracked)
Heres the third message, of which we know the type of cipher and have a clue on what the key for the message. The last code mentioned that "the key is the hidden symbol of death in my favorite holbien." Holbien is a 16th century painter who put a lot of easter eggs into his paintings. The particular painting that is mentioned in the last message is this one:
Hidden symbol of death? A distorted skull sounds like it. Except, the key, to my fustration, the key is not the word skull, its the word:
Thats right. The keyword is "Sskkuullll." Seems like its no big deal, but trust me, I wrestled with the decryption for a good 2-3 days before I had fully decoded it. Anyways, heres the decrypted message: "start warning i heard report of our break in on the news still waiting on alarm test schedules i will report back tomorrow with final plan for extra security i suggest we burn our letters after reading and switch our letters to numbers using polybius square drop message under the bench at train station end." This is a lot of information, including the next message's cipher. Time to work on the next one.
Message #4: (Uncracked)
(Placeholder text)