Puzzlemaster Aaron Steimle of the Muppet Liberation Front contributed to this post.

Every year, EFF joins thousands of computer security professionals, tinkerers, and hobbyists for Hacker Summer Camp, the affectionate term used for the series of Las Vegas technology conferences including BSidesLV, Black Hat, DEF CON, and more. EFF has a long history of standing with online creators and security researchers at events like these for the benefit of all tech users. We’re proud to honor this community’s spirit of curiosity, so each year at DEF CON we unveil a limited edition EFF member t-shirt with an integrated puzzle for our supporters (check the archive!). This year we had help from some special friends.

"The stars at night are big and bright down on the strip of Vegas"

For EFF’s lucky 13th member t-shirt at DEF CON 30, we had the opportunity to collaborate with iconic hacker artist Eddie the Y3t1 Mize and the esteemed multi-year winners of EFF’s t-shirt puzzle challenge: Elegin, CryptoK, Detective 6, and jabberw0nky of the Muppet Liberation Front.

Extremely Online members' design with an integrated challenge.

The result is our tongue-in-cheek Extremely Online T-Shirt, an expression of our love for the internet and the people who make it great. In the end, one digital freedom supporter solved the final puzzle and stood victorious. Congratulations and cheers to our champion cr4mb0!

But How Did They Do It?

Take a guided tour through each piece of the challenge with our intrepid puzzlemasters from the Muppet Liberation Front. Extreme spoilers ahead! You’ve been warned…

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Puzzle 0

The puzzle starts with the red letters on the shirt on top of a red cube. Trying common encodings won’t work, but a quick Google search of the letters will return various results containing InterPlanetary File System (IPFS) links. The cube is also the logo for IPFS. Thus, the text on the shirt resolves to the following IPFS hash/address:

ipfs://bafkreiebzehf2qlxsm5bdk7cnrnmtnojwb53bnwyrgkkt7ypx5u53typcu

QR codes have a standard format and structure that requires the large squares to be placed in three of the four corners. With this in mind, the image can be seen as four separate smaller squares, with the two middle ones overlapping at the large square in the center. These squares can be reconstructed into a valid QR code using an image editing program.

Answer:

Resolves to https://eff.org/Defcon30EFFPuzzleExtraordinaire

This site contains two groups of text: the first paragraph contains four lines that start with the same letters, and the second paragraph looks like Base64-encoded information. Notice that the four lines in the first paragraph all start with the same letters as the text on the shirt. These are also IPFS addresses of the remaining puzzles.

Puzzle 1

ipfs://bafkreigex7eadjwdggka7t6h2ln66ck5wuecq7gnryaayqjcirmdyjgwoe

Wordle players will immediately recognize the style of the puzzle. You can use a wordlist and some regular expressions / pattern matching to identify the only possible solution to this puzzle. Note that the first five words also act as a hint to the theme of each puzzle answer: space/stars.

Answer: PEACOCK

Puzzle 2

Challenge Text

Word on the street is that the font of youth is the key.

[Flight enabling bird feature.] + [Short resonant tones, often indicating a correct response.] + [First Fermat Prime]

55rhyykkqisq 4ubhYpYfwg 5pYrmmkks6qi prkuy6qlf eakjZjk4a rhXkgwy6iqhrddb

This puzzle consists of some cryptic clues and a line of ciphertext. First, consider the wording of the initial line: “Word on the street is that the font of youth is the key.” These clues should indicate that the solver will need to look into Microsoft Word Fonts.

Next, to decode the clues in the second line:

1. Flight enabling bird feature = WING
2. Short resonant tones, often indicating a correct response = DINGS
3. First Fermat Prime = 3

∴ WINGDINGS 3

Decoding the Cipher Text

55rhyykkqisq 4ubhYpYfwg 5pYrmmkks6qi prkuy6qlf eakjZjk4a rhXkgwy6iqhrddb

The solver now knows that the ciphertext has something to do with Microsoft Word and the Wingdings 3 font. Typed out in Wingdings 3 font, each character results in some type of arrow. The characters are categorized as arrows as follows:

UP: XYhpr5
DOWN: iqs60
LEFT: Zbdftv
RIGHT: aceguw4
UP-LEFT: jz
UP-RIGHT: k
DOWN-LEFT: lx
DOWN-RIGHT: my

Using these arrows as instructions to a pen, one can draw shapes that resemble letters. Each word of the ciphertext should map to a single letter, with a new plot starting after each space.

Solution

Reading the drawn shapes as letters – the solution: MIMOSA

Puzzle 3

Puzzle solution:

"The name of the game isn’t Craps" and the picture of a person snapping their fingers are references to the game "Snaps." The puzzle uses the rules of Snaps transferred onto a Craps board. Snaps is a game where a clue-giver uses statements and finger-snapping to spell out a well-known name.

Looking at the differences between the given board and a standard Craps board indicates which components are meant to give clues. In a game of Snaps, vowels are indicated by the number of snaps, translated here as the number of pips shown on the colored die. Consonants are indicated with the first letter of a statement given by the clue-giver. On this board, "COME," "NOT PASS BAR," "PASS LINE," and "HOW TO PLAY" have been added or altered, indicating that these statements give the necessary consonants C, N, P, and H by taking the first letter of each statement, as in the game Snaps. The dice have been colored, giving the numbers 1-4 which in Snaps indicate the vowels A, E, I, and O. To order these elements, the rainbow circles to the left of the dice have been colored with the corresponding colors, giving the answer PHOENICIA.

Final answer: PHOENICIA

Puzzle 4

Puzzle Solution:

Unlike the previous puzzles, this image does not take up the entire page, indicating that there might be more information available by inspecting the html. Doing so shows that the embedded image has the file name "OrangeJuicePaperFakeBook.jpg." Deconstructing this, "OrangeJuicePaper" clues the word "pulp" and "FakeBook" clues the word fiction, letting the solver know the puzzle's theme will revolve around the movie Pulp Fiction.

The image itself is hiding information steganographically, and the information can be extracted using the tool steghide. Using steghide on OrangeJuicePaperFakeBook.jpg with no password will write the file QuartDeLivreAvecDuFromage.txt, containing a long series of binary strings of length 8.

'Quart de livre avec du fromage' is 'quarter pounder with cheese' in French. "Do you know what they call a quarter pounder with cheese in Paris?" is a quote from Vincent Vega in Pulp Fiction.

The binary numbers within the file are the ASCII representation of letters and spaces, and can be converted using any of the many tools available upon searching for "binary ASCII converter." Converting the file contents gives legible but nonsensical results:

overconstructed efficiencyapartments coeffect jeffs counterefforts phosphatidylethanolamines eye effed I nonefficient aftereffects theocracy teachereffectiveness inefficaciousnesses a ineffervescibility psychoneuroimmunologically superefficiency coefficientofacceleration o toxic jeffersonian teffs differentialcoefficient milkshake propulsiveefficiency effulges bad lockpick effed upper nonrevolutionaries revolutionarinesses teffs temperaturecoefficient maleffect effable foe butterflyeffect eerie tranquillizing magnetoopticaleffect jeffs plantthermalefficiency nulls rappers I effectiveresistance

These words aren't used directly, but instead the length of each word is relevant. Converting each word to its character count, and then converting that character count to its letter of the alphabet gives: othenyceallitsarzoyaelewithcheersevigcoentevegas

"They call it a royale with cheese" is another quote from Vincent Vega, also the answer to the previous quote ("Do you know what they call a quarter pounder with cheese in Paris?").

Looking at othenyceallitsarzoyaelewithcheersevigcoentevegas, it contains "they call it a royale with cheese," followed by "vigcent vega." The extra characters mixed in spell 'ones zeroes,' which is a hint that each of the nonsensical words should be converted to a one or a zero themselves. But how? Looking back at the original image, it shows that the EFF score is 1 and the DEF CON score is 0—so represent each word containing the letters "EFF" with a 1, and all other words with a 0. This gives a new binary string, which can itself be again converted to ASCII, giving the ciphertext ymgdzq.

Going back to the quote derived from counting the number of characters in each word, note that Vincent was intentionally misspelled as Vigcent. This is a clue to use a vigenere cipher to decrypt this new ciphertext with key vega.

Applying Vigenere to text 'ymgdzq' with key 'vega' gives the solution: DIADEM

Bonus Easter Egg: The first character of each non-eff word in the wordlist results in: opeitapotmblunrfetnri, which anagrams to muppet liberation front.

META

The final block of text is encoded in Base64. Decoding it reveals that the data starts with "Salted__", an artifact of encrypting using OpenSSL.

Concatenate the answers from the four previous puzzles in alphabetical order to create the passphrase that will be used to decrypt the text. With the block of text placed in a file called final.enc, the openssl command to decrypt the text is as follows:

$ openssl aes-256-cbc -d -in final.enc -out final.txt
enter aes-256-cbc decryption password: DiademMimosaPeacockPhoenicia

Decrypting it reveals the solution to the puzzle:

"On behalf of EFF and Muppet Liberation Front,

congratulations on solving the puzzle challenge!

Email the phrase 'The stars at night are big and bright down on the strip of Vegas' to membership@eff.org"

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EFF is deeply thankful to the Muppet Liberation Front members for creating this puzzle and Eddie the Y3t1 for designing the artwork. After all, how can we fight for a better digital future without some beauty and brainteasers along the way? The movement for digital rights depends on cooperation and mutual support in our communities, and EFF is grateful to everyone on the team!

Happy Hacking!