Chances are if you frequent the more nerdy side of the internet you might have heard of Cicada 3301. In short, back in 2012 an image was left on 4chan with a message hidden inside of it. It was the first of several puzzles and today people still are trying to solve the last one.
Rather than do a poor job at relaying the story, you can watch a 4 part series that does a really good job on catching you up on the whole story to where we are now. You can find the videos here.
Part of the fun is learning about cryptography and problem solving, and I cam across a tool called outguess. It can be used to hide information within an image and is great fun to play with. Unfortunately it’s no longer developed and the package was no longer maintained in the AUR of Arch which I used to play with it. I installed it using a AUR helper but it errored. So, I removed it, downloaded the source code and compiled it myself and it ran great.
I’ve put the source in a public git repo which you can find here
Clone the repo and run the following to compile and build it:
$ ./configure && make
Enjoy.