August 15, 2014 | By Bill Budington and Aaron Jue

EFF's Defcon 22 T-Shirt Puzzle Explained

This summer we proudly unveiled EFF's fifth limited edition member t-shirt to DEF CON 22 attendees at the annual hacker conference in Las Vegas. Secretive organizations scheming global domination and watching everything you do may not be very far fetched, but we've turned that concept on its head with a digital freedom society-themed motif created by EFF Senior Designer Hugh D'Andrade. Together we are growing our own conspiracy to defend privacy and free expression for all. Hidden within the rich mystic symbolism of the crossing keypair, ethernet cable crest, lockpicks, and anti-surveillance eye is a secret puzzle for you to decipher, the likes of which would make even Voynich jealous! Warning: spoilers are ahead, and you already know too much!

Displayed on the left is the original shirt as seen in plain daylight. But under the shine of a blacklight, the ciphertext is revealed:

[Iikcggu] Gvdw ag etxlku | [Ptjhafvmkx] rqgrva(cgvs urlaiaixcm Asiixl) | [Gwhusu] akksdx bzqaymoukh(gsyi, Jnsrgo) | [Rmtm] mwllzg(ihrl.qv_e? Wkivav)

What does it mean? A second text is highlighted with the blacklight:


Our super secure Key Derivation Function comes in the form of a dictionary. Translated from Latin into English, this phrase becomes:

Everyone has something to hide

And how do you decode the ciphertext? Using a cipher developed in the 16th century called the Vigenère cipher:

[English] Code is speech | [Javascript] assert(code instanceof Speech) | [Python] assert isinstance(code, Speech) | [Ruby] assert(code.is_a? Speech)

The plaintext reminds us of an important ruling made in the historic case Bernstein v. US Department of Justice, which EFF litigated: source code is a form of speech constitutionally protected by the First Amendment. Special congratulations go to 1o57 and the council of 9 for being the first to solve this year's puzzle!

Photo Credit: junkmail.  CC Attribution 2.0

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