After only a few minutes work he’d got somewhere: a reference to "Tiberius Claudius Caesar” and a line of meaningless letters.Joel deduced it might be an embedded "Caesar cipher” – an encryption technique named after Julius Caesar, who used it in private correspondence.It replaces characters by a letter a certain number of positions down the alphabet.
"But it seemed like the challenge was a bit harder than a Caesar cipher after all.
I was hooked.” Eriksson didn’t realise it then, but he was embarking on one of the internet’s most enduring puzzles; a scavenger hunt that has led thousands of competitors across the web, down telephone lines, out to several physical locations around the globe, and into unchartered areas of the "darknet”.
So far, the hunt has required a knowledge of number theory, philosophy and classical music.
An interest in both cyberpunk literature and the Victorian occult has also come in handy as has an understanding of Mayan numerology.
It has also featured a poem, a tuneless guitar ditty, a femme fatale called "Wind” who may, or may not, exist in real life, and a clue on a lamp post in Hawaii.
Only one thing is certain: as it stands, no one is entirely sure what the challenge – known as Cicada 3301 – is all about or who is behind it.
Depending on who you listen to, it’s either a mysterious secret society, a statement by a new political think tank, or an arcane recruitment drive by some quasi-military body.
Which means, of course, everyone thinks it’s the CIA.
One evening in January last year, Joel Eriksson, a 34-year-old computer analyst from Uppsala in Sweden, was trawling the web, looking for distraction, when he came across a message on an internet forum. Find it, and it will lead you on the road to finding us.