@inversecos

When it comes to cracking steganography – like other capture-the-flag challenges, there's a particular methodology you can follow. While there are a myriad of online decryption and encryption tools, the goal of this guide is to show you how to analyse files and learn how steganography works. In this guide, we're going to examine file compressions and least significant bits – the tools and the methodology you can follow. 1. File and Strings  First and foremost, when you get an image, the first step is to boot up your terminal and run 'file' in the command-line to examine the file. Given it's a png or a jpg image – take particular note of the size of the image and the colour depth of image – is it 8-bit or 16-bit? $ file photo.png For a passive overview of possible messages stored within the image, run the 'strings' command and see if there are any hidden text of interest. Sometimes, useful sentences can be configured within the file – I once...