Cicada 3301
An anonymous 2012–2014 internet recruitment puzzle that combined steganography, classical ciphers, GPS coordinates on physical posters, and a copy of the Liber Primus hand-illustrated in glyphic runes.
Interactive Exhibit
Step through the four major puzzle layers used in Cicada's 2012 release: Caesar decode, URL extraction, image steg hint, and book-cipher index. Each button reveals the kind of move solvers had to make. Track B — narrative walkthrough.
Why This Matters
On 4 January 2012 a plain image appeared on 4chan reading 'Hello. We are looking for highly intelligent individuals.' Solving it required Caesar-shift decoding, OutGuess image steganography, a book code on the Mabinogion, a call to a Dallas telephone number, a prime-number step, GPS coordinates that pointed to QR-coded posters in cities on several continents, a second book code on William Gibson's Agrippa (A Book of the Dead), and ultimately a Tor hidden service. Two further puzzles ran in 2013 and 2014. The third culminated in a hand-bound book — Liber Primus — written in a runic alphabet, only the first 19 pages of which have ever been decrypted. The identity of '3301' has never been confirmed.
The 2012 puzzle alone employed: a Caesar shift, digital steganography (the OutGuess tool), URL discovery, a book code on the Mabinogion — the "Lady of the Fountain" text as printed in Bulfinch's Mythology — a telephone recording that set a prime-number task, a second book code on Gibson's Agrippa (A Book of the Dead), and finally an invitation by private email. Solvers who finished within the deadline reported being asked to write essays on cryptography and privacy; some never heard back. Theories about who '3301' was range from a private intelligence-recruitment outfit to a libertarian cryptography collective.
Cicada is the most cryptographically sophisticated public puzzle ever issued. It demanded competence in classical substitution, modern image steganography, prime-number theory, GPG/PGP key handling, Tor onion routing, and rare-language linguistics (the Liber Primus rune system appears to be a custom Anglo-Saxon-styled runic encoding of English with an as-yet-unknown additional cipher layer). The undecrypted pages remain an open public cryptanalysis target.
Cicada 3301 is the standard reference example of a modern puzzle ARG (alternate reality game) used as cipher pedagogy. It established a template followed by recruitment puzzles from GCHQ (the 'Can You Find It?' challenge) and the NSA (NSA-Codebreaker Challenge for university students). The Liber Primus remains a living unsolved document, regularly reattacked by new generations of cryptanalysts.
| Hall | Hall XIII · Culture |
| Region | Global (online + physical posters in 14 cities) |
| Era | Internet era · 2012–2014 |
| Discipline | Multi-cipher composite |
| Track | B (puzzle-stage walkthrough) |
| Modern echo | Steganography · book ciphers · puzzle recruitment |
- Wikipedia — Cicada 3301 ↗
- Boxentriq — Cicada 3301 first-puzzle walkthrough ↗
- Uncovering Cicada Wiki — What Happened (2012) ↗
- Grantland — A Wild-Bug Chase: Cracking Cicada 3301 ↗
This page previously named a book — "Mariko Ōhara's Mental Fitness Puzzles" — and quoted a recorded phone message, neither of which appears in any documented account of the 2012 solve. Both have been removed. The recording's wording is paraphrased here rather than quoted, because no verbatim transcript of it could be verified.