Steganography is the art and science of hiding messages, files etc. In a way that no one, except recipient, suspects that it even exists. Jump to the end to learn how to hide text or any file (even executable) in picture using Linux and Windows command line.
Steganography has long and interesting history, I’m just going to share 2 old examples for introduction to the topic.
First recorded example of steganography happened in Ancient Greece 440 BC. Upon separation, Herodotus told his vassal “When my messenger comes, shave his head and look there.” When the time came, Herodotus shaved his slave’s head and tattooed the message. When the hair regrew, he was sent to deliver the message.
Another one I like was a message from a prisoner of war in 1941. He used knitting to write a message in Morse code:
In case you were wondering, messages are: “fuck hitler” and “God Save the King”.
Images are most common digital medium, but there are many other. You can hide data in music files and if you have a lot of data, videos might be good.
Hiding Data in Images
This procedure is very size limiting, you obviously can’t put