Cicada 3301 is a nickname given to an organisation that, on three occasions, has posted a set of puzzles to recruit codebreakers from the public. The first internet puzzle started on January 4, 2012 on 4chan and ran for nearly a month. A second round 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 which were to be solved. No new puzzles were published on January 4, 2015. However, a new clue was posted on Twitter on January 5, 2016. In April 2017, a verified PGP-signed message was found.[6] It explicitly denies the validity of any unsigned puzzle. A verified puzzle has not been posted since.
source: https://en.wikipedia.org/wiki/Cicada_3301
The puzzles focused heavily on data security, cryptography, steganography, and internet anonymity
