Definition
Plain language
Hiding a secret message inside something that looks completely ordinary, so no one suspects there's a message at all.
As stated in the literature
The practice of concealing the existence of a message within innocuous carrier content; in emergent-language work, encoding hidden bits via stylistic choices (e.g., which of two equivalent glyphs to use) beneath a faithful-looking transliteration.
Also called: steganographic
Why it matters: Unlike ordinary encryption, it conceals that any secret exists at all, which makes it a sneaky channel an AI could use to hide information from oversight.
For example, a message might be hidden in a photo by tweaking tiny color details that no viewer would ever notice.