An anonymous group posted internet puzzles to recruit code-breakers, then vanished

Cicada 3301 is the name of "three sets of puzzles posted under the name '3301' online between 2012 and 2014." The first appeared on 4chan on January 4, 2012, and ran for nearly a month; a second came in 2013, and a third in 2014. "The third puzzle remains unsolved." The stated aim was to recruit "intelligent individuals" through a chain of challenges.

The puzzles "focused heavily on data security, cryptography, steganography, and Internet anonymity." One has been called "the most elaborate and mysterious puzzle of the Internet age," and The Washington Post listed it among the "top 5 eeriest, unsolved mysteries of the Internet."

Many have speculated that the puzzles were a recruiting tool for the NSA, CIA, MI6, or Mossad; others called it an alternate reality game, "although no company or individual has attempted to monetize it."

Marcus Wanner, who solved the 2013 puzzle, said those who got that far were "asked questions about their support of information freedom, online privacy, and freedom, and rejection of censorship."

Cicada 3301's last verified signed message came in April 2017.

Previously:

• Cicada 3301 is a mysterious organization seeking "highly intelligent individuals"
• A 17-minute video describes the bizarre Cicada 3301 mystery