Invented by Peter Wayner in 1991, Mimic Functions are an application of context-free grammars to the field of Steganography. Using Mimic Functions one can hide information in innocuous form.

The power of Mimic Functions over other Steganographic techniques is that the form that the hidden message takes is limited only by the imagination and resourcefulness of the grammar composer (see spammimic for one possible implementation). Thus, one is not limited to the least significant bits of graphics, sound or text files (all techniques which can be relatively easily analyzed). Another way Mimic Functions resist steganalysis is by having the hidden message take on the statistical properties of the innocuous source.

Mimic Functions are one of the most underrated inventions in the field of Steganography.