Advent Calendar : Day 3

[Kathis]

Another day another code, what task will be ask of you this time I wonder. 

 

We could do a Vigenere cipher. With a twist. Though I am fairly certain a lot of you didn't understand how they worked. So we'll go with a tutorial

 

Lets say your plain text was igi

And your key was emotional

You would first get your word and look at your first keyword letter, E in this case, and line it up to the i, in this case we get M
then you would look the next letter in your keyword, which is M, and line it up to the g, which is S
and then you would look at the O, in your keyword, and line it up with your i again, giving you W 
 

Below is highlighted to show how the same plaintext letter does not mean it's the same letter.

 

so igi with the keyword emotion, would be MSW.   If you run out of keyword letters, you start again from the first one again, which would be E.

 

So that's how this cypher works.  Now for the twist. Your plain text letters is backwards, and you need 2 key words. 
Jelly  is for your odd letters, 

RO is for your even.

 

Your cypher is.

 

 

Good luck everyone.

[Kathis]

A FINAL reminder.

 

Quote

There are no IP restrictions on entering the code, as we understand many of you play with family members. However, we kindly ask that you honor the spirit of the event by redeeming the code only once per person. While it is technically possible to redeem it on multiple accounts, we can track redemptions and appreciate your cooperation in keeping things fair for everyone.

Redeeming it on multiple accounts, will be seen as Malicious interference with an event.  And I will mute every character on the accounts involved. If you had problems redeeming it on an account, let me know. I can see which accounts figured out the codes and redeemed them. If it turns out that you just gave the code to someone, I'll consider you also at fault, (because trust me, if someone gets muted they will more than likely call out names, and an investigation will occur). 

 

[tachy]

Nice one. I fell for it badly and started to question my ability to spell CHRISTMAS and do arithmetic 🤡 

Thankfully, Adam had great hints pointing to the right direction.

[Kathis]

I think the best hint I can give people is to make the grid by hand, but start from the bottom. it just makes things easier. 

[The Chief]

Nice one today ! That was fun. 

[Kathis]

So a few of you were a bit confused. So lets tackle the hardest part first. 

 

Solution: SPMTGBALTXKOYQBR

 

How to Solve: 

The hardest part was figuring out the grid. I stated 'Your plain text letters is backwards'

The thing about the Vigenere cipher is that there are many ways to get to the right answer.  Why? Because Math I guess. 
 

• Some could have just reversed the top row, (the A-Z header where it says plain text) and used that with your keys instead, and get the answer. 
• Some of you may have gone find a Vigenere Cipher decoder, put in ZYXWVUTSRQPONMLKJIHGFEDCBA for the alphabet, dropping in the cypher Christmaspudding, with the proper key, and got the answer that way. 
• But most of you had reversed the grid, because I am assuming that WhiteDeath assisted.

 

So we'll go through the third method, since that was more community bonding. 

 

So many of you understood that ZYXWVUTSRQPONMLKJIHGFEDCBA (Z-A)  was involved. 

So we start at Z,Z and continue up.  Since Vigenere Cipher and work up. 

 

 

We can shorten this a bit, since we know that we don't need every letter. Our two Keys are  JELLY   and RO  so we just need EJLORY 
So here is the simplified version.

 

 

Jelly  is for your odd letters, 

RO is for your even.

 

Now I will state that unless specified, lowercase in these ciphers can be assumed to be non-existant. (But in future puzzles it might go a-zA-Z  meaning that it will contiune after  a,b,c...x,y,z,A,B,C...X,Y,Z) Since this was not specified, you can assume it's JELLY RO  

 

Odd letters will be the first key, and the even letters is the second. Lining up to our cypher, we know the key is

 

J    R    E    O    L    R    L    O    Y    R    J    O    E    R    L    O
To our cypher
C    H    R    I    S    T    M    A    S    P    U    D    D    I    N    G

 

So from here you look for plug in the Cypher, and line it up to the key. I won't line them up. for you but you can follow along. 

 

C and J,   S is the intersection

H and R, P is the interesection

R and E, M is the intersection

So on and so forth. 

 

keep doing this, and you will get SPMTGBALTXKOYQBR.

 

 

But Kathis~ that makes less sense..how is the solvers doing it? 

 

In a weird twist of math. You might have seen the second point. 

 

So lets explore what the AI overlords are doing, so you understand.  Since the important part is understanding how this works. 

 

 

You could have still got the same answer, by taking the J,  line up to the C in the grid,  and follow it up the S at the top.   
repeat for each letter. 

As I stated. you could have came at this from multiple directions, and it would still give you the same answer. 

 

Don't worry I won't be doing many more of these 2 ciphers you done. Since you had your fill of them over Halloween, and these were kind-of the test of understanding. …Also I totally understand that my English can be a bit...bad. I go through what I have written, and try to reword things so they are a bit clearer, but it just becomes more of a mess.