Duck and uncover
Around five years ago, a mysterious organisation named Cicada 3301 began posting a series of increasingly difficult puzzles online in a bid to recruit “highly intelligent individuals”. The first puzzle in 2012 was an image with a small text file at the end. This was encoded with a simple Caesar cipher whereby each letter of the alphabet is shifted a certain number of letters (in this case four).
This in turn led to an image of a wooden duck with the message “Woops! Just decoys this way. Looks like you can’t guess how to get the message out.” Savvy crypto-nerds across the world combined their collective genius and realised that the words “guess” and “out” meant that there was a message hidden in the image using Outguess. The solution to this puzzle led to another on a Reddit page based on Mayan numerals. As you need to solve each puzzle to continue onto the next, only a handful of people claim to have completed Cicada 3301’s challenges and their claims are hard to verify after solutions are posted publicly.
We know virtually nothing about who Cicada 3301 are or why they are trying to recruit gifted people. Challenges in subsequent years became increasingly complex, involving QR codes on lamposts from Poland to Hawaii as well as custom websites and recorded telephone messages. The puzzles stopped around a year ago but those interested in seeing past challenges can visit https://cicada3301.org.