Write-up
Note at Sparkles' house
Visiting winterbash2022.stackexchange.com/visit-sparkles reveals:
It's that time of year. Sparkles the Unicorn has been enjoying a year of bliss and vacation, and now it is time to fulfill her holiday duties to spread joy as far as it can go.
You walk to Sparkles' house. As you move to press the doorbell, a note tacked to the door catches your eye. It reads:
BPM CVQKWZV UCAB ZMUIQV NZMM
AMJH OCZ XJMMPKODIB DIAGPZIXZ
WN BPM KWUXCBMZ.
FVB?
HP OZ YZE MPWTPGP JZF.
JR QB ABG ORYVRIR LBHE YVRF.
RZ YJ IJO WZGDZQZ TJPM OZMMDWGZ XDMXPDOMT.
UVY KV DL ILSPLCL FVB HYL VYNHUPJ PU UHABYL.
EM PIDM BISMV GWCZ CVQKWZV.
MNIFYH MJULEFYM ZLIG NBYCL BIGY.
XKGJ UAX TUZK, ROTK HE ROTK.
LHJO SPUL, H SLAALY. MYVT AOLT, H SVJHAPVU.
DGLB SQ. RUM UMPBQ, MLC NJYAC.
ACZGP ESLE JZF LCP SFXLY.
Sparkles is not home. Where did she go? Or… where was she taken…?
Obviously, there is an encrypted message. From the source code of the website, you can get the following additional hint:
<!-- What *rotten* luck! Not only is Sparkles missing, but it looks like you'll have some unscrambling to do if you want to defend the unicorn. -->
"Rotten" is a hint for rot n
a. k. a. Caesar cipher. You can use dcode.fr to decode the message. You will notice that each line uses its own key. Decoding each line reveals the following message:
THE UNICORN MUST REMAIN FREE
FROM THE CORRUPTING INFLUENCE
OF THE COMPUTER.
YOU?
WE DO NOT BELIEVE YOU.
WE DO NOT BELIEVE YOUR LIES.
WE DO NOT BELIEVE YOUR TERRIBLE CIRCUITRY.
NOR DO WE BELIEVE YOU ARE ORGANIC IN NATURE.
WE HAVE TAKEN YOUR UNICORN.
STOLEN SPARKLES FROM THEIR HOME.
READ OUR NOTE, LINE BY LINE.
EACH LINE, A LETTER. FROM THEM, A LOCATION.
FIND US. TWO WORDS, ONE PLACE.
PROVE THAT YOU ARE HUMAN.
And these are the keys for all lines (both directions):
Line |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 |
14 |
-> |
8 |
21 |
8 |
7 |
11 |
13 |
21 |
7 |
8 |
20 |
6 |
7 |
24 |
11 |
<- |
18 |
5 |
18 |
19 |
15 |
13 |
5 |
19 |
18 |
6 |
20 |
19 |
2 |
15 |
The message tells you to derive one letter from each line and to create two words from them. But how?
There are no more hints, except: each line was decoded by a different key. The keys of a Caesar cipher will be in range of 1 to 25. So these keys can in turn be used to describe letters of the alphabet. And there is a name for that: Letter Number Code (A1Z26). You can use dcode.fr again to decode the numbers, which will give you:
HUHGKMUGHTFGXK
and
RERSOMESRFTSBO
for both key sets.
It looks like both decoded strings do not provide two words already. Strings, where the order of the letters has been scrambled, are called anagrams. And dcode.fr will help you again to decode the anagrams. From the second string, you will get SOMBER FORTRESS
among other solutions, which is indeed the location you are looking for: winterbash2022.stackexchange.com/somber-fortress
To be honest, there is/was another way to get to this URL way quicker. Having a look at the web archive reveals that the above URL has already been crawled on 2022-12-23 and it is/was the only one that does/did not lead to hats and stuff.
Somber fortress
Visiting winterbash2022.stackexchange.com/somber-fortress reveals the next part of the challenge:
You arrive at the gate to a large, ancient fortress. The air is cold, and the stone walls are a dismal grey. You can see Sparkles beyond the gate, trapped once again. Sparkles sees you, and rushes towards the gate. The gate, however, holds firm.
On the wall next to the gate is an alphanumeric keypad with a small note taped to it. You're concerned for a moment that someone wrote the access code on the note. That'd be very poor security! But no, thankfully it just says /##£
.
In front of you is a pressure plate, and a large leather knapsack sitting atop it. The bag is empty. You push the bag to the side, and stand on the plate. Glowing letters appear in the surface of the obsidian wall. They read:
SURELY A COMPUTER COULD NEVER SOLVE SUCH A PROBLEM.
THE WEIGHT'S THE KEY, YOU SEE.
AND COMPUTERS WEIGH NOTHING.
Seven stones fall from the ceiling around you, crashing into the floor below. You narrowly dodge these stones, and the dust takes a moment to settle.
Once the dust clears, you can see that the stones vary in their weights and sizes. On each stone is printed a set of letters. Each stone also fills the bag a specific amount. Thinking quickly, you pull your notepad out, and form the following table:
% of bag filled |
Text on the stone |
12% |
ONTMCR |
18% |
MLRKAP |
27% |
EDJCSH |
32% |
LKQJZO |
54% |
CBHAQF |
74% |
UTZSIX |
86% |
QPVOET |
From the note, you can derive that for the next link you will have to append something like /##£
to the URL. Furthermore, the challenge text says that there are stones that have a weight and a volume. The volume is given in the table, but not the weight. The texts on the stones all are Caesar ciphers of POUNDS
. So you are probably looking for a weight. Going back to the note, remember that there is only an alphanumeric keypad. So it will not be possible to input £
. As we are looking for a weight, lbs
should be a valid replacement for £
. So we are actually looking for a URL like /##lbs
.
"THE WEIGHT'S THE KEY" suggests that there is a meaning in the Caesar keys again, like in the first riddle. And just assume what it says: The keys represent the weights of the stones. These are the keys/weights:
Stone |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
-> |
25 |
23 |
15 |
22 |
13 |
5 |
1 |
<- |
1 |
3 |
11 |
4 |
13 |
21 |
25 |
With the volumes given, you cannot fill the bag by 100%. So try to fill it as much as possible. Stones 2, 3 and 5 will fill it by 99%. The bag will then have a weight of 51 or 27, depending on the key set. And 27 seems to be the correct answer.
Another way to get to the URL is to use brute force. The following PowerShell snippet will give you the correct URL in seconds:
10..99 | ForEach-Object {
$url = "https://winterbash2022.stackexchange.com/$($_)lbs"
try {
$a = Invoke-WebRequest -Uri $url -UseBasicParsing
Write-Host "$url" -ForegroundColor Green
} catch {}
}
Result: winterbash2022.stackexchange.com/27lbs
Quiz
Visiting winterbash2022.stackexchange.com/27lbs reveals the final part of the challenge, the quiz:
There she is! You have are almost there!
Can you help lead the unicorn to safety, and earn the vaunted Defender of the Unicorn
hat? To do so, you must answer 10 questions correctly, with the following stipulations:
- All answers are either integers or at most two words (no punctuation, spaces optional), case insensitive
- All answers are discoverable through Stack Overflow/Stack Exchange sites/blogs
- If you get a question wrong, you will have a one minute timeout before you can attempt another answer
- If you get three questions wrong, Sparkles will strike out on her own
- Your progress will reset after two hours of inactivity
- Please do not share answers to questions with others before January 4, 2023 at 21:00 UTC.
- The Defender of the Unicorn hat will only be awarded on Meta Stack Exchange. If you do not have an MSE user, you are welcome to go through the quest, but you will not be awarded the hat.
- GL,HF!
To finish the challenge, you have to answer 10 random questions from a question pool. Some of the questions are:
What is the name of the design system created and maintained by Stack Exchange?
Stacks
How many inductees does the Stack Exchange Security Hall of Fame have?
29
What was the name of the event in 2011 that eventually became Winter/Summer Bash?
Hat Dash
What unofficial term is used to describe the act of mindlessly completing reviews without regard to the post's actual quality?
robo-reviewing
What's the official name of the chat system used on the Stack Exchange network?
Bonfire
How many (non-employee) moderators (unique accounts) moderate the network?
539
What is the maximum amount of reputation someone can earn by suggesting edits?
1000
How many active network sites are there as of December 2022?
180
What tag had the most questions asked on Stack Overflow in 2022?
python
In what year was the highest-scoring Artificial Intelligence question asked?
2016
What feature got a major upgrade and rename this year?
Saves
["Bookmarks" was also accepted as an answer here]
What tool did people use to answer large numbers of questions in December 2022?
ChatGPT
What site did we bid farewell to this year?
Windows Phone
What is the name of the staging zone where new Stack Exchange sites can be proposed?
Area 51
How many users total across the Stack Exchange network have at least 1 million reputation on a single site?
8
What is the highest reputation required on any site to create new tags?
1500
Which site was most recently added to the Stack Exchange network?
Solana