What is steganography?
Steganography is a way to hide information for its secret keeping and transmission. By sense, it’s specific sort of encryption — not by direct ciphering, but by mixing one information with other, in a way and proportion keeping hidden information invisible to other. More information about steganography you can find in article on Wikipedia. Here I just notice, that steganography (or «stego», how it named in jargon) sometimes used by cybersecurity specialists to hide important data and dispatches.
Python implementation
For educational purposes, I implemented example steganography app, and published its source on GitHub. You can download it here: PySteg
Example
At first glance, this is garish AI-generated picture of Thai street. Nothing special.
But actually, inside this picture embedded a blueprint of a spacecraft (of course, AI-generated and fictional):
With pre-encrypting (using my AES encryption tool) hidden information is practically undetectable with any tools, including AI.
Interesting, that AI-generated pictures, «dirty» and slightly fuzzy by nature, appeared to be best «carriers» for hidden information.