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 puzzle came out at 2012 april 1st when a user on 4chan posted an image.

This is actually a hidden message in the image!

Using a text extractor tool,you can find a hidden message

Then you can use a caesar cipher tool to find the other text

which leads to a imgur image

It contains two key words Guess & Out.This indicates that you need to use the tool OutGuess to find the hidden message again.

If you did use OutGuess,then you will get a more interesting message:

‘Here is a book code.To find the book,and more information, go to www.reddit.com/r/a2e7j6ic78h0j/

1:20

2:3

3:5

4:20