Cicada 3301

Cicada 3301 is a nickname given to three sets of puzzles posted under the name "3301" online between 2012 and 2014. The first puzzle started on January 2, 2012, on 4chan and ran for nearly a month. A second round of puzzles began one year later on January 4, 2013, and then a third round following the confirmation of a fresh clue posted on Twitter on January 4, 2014. The third puzzle has yet to be solved. The stated intent was to recruit "intelligent individuals" by presenting a series of puzzles to be solved; no new puzzles were published on January 4, 2015. A new clue was posted on Twitter on January 5, 2016. Cicada 3301 posted their last verified OpenPGP-signed message in April 2017, denying the validity of any unsigned puzzle.

The puzzles focused heavily on data security, cryptography, steganography, and internet anonymity. It has been called "the most elaborate and mysterious puzzle of the internet age", and is listed as one of the "top 5 eeriest, unsolved mysteries of the internet" by The Washington Post, and much speculation exists as to its function. Many have speculated that the puzzles are a recruitment tool for the NSA, CIA, MI6, a "Masonic conspiracy", or a cyber mercenary group. Others have stated Cicada 3301 is an alternate reality game, although no company or individual has attempted to monetize it. Some of the final contestants believe that Cicada 3301 is a remnant of the late 1980s and 1990s Cypherpunk movement.