This act takes its name from a three volume work on communicating with  supernatural beings by Trithemius.
One method for doing this on on 8 by 8 blocks of canonical gray coding is bit plane complexity  segmentation. Gustavus Simons introduced the Prisoner's Problem to study this action. A simple digital  method for doing this is least significant bit insertion. Gerolamo Cardano developed a grille of rectangular  holes in paper for doing this. This act takes its name from a three volume work on communicating with  supernatural beings by Trithemius. OpenPuff is a program for doing the "deniable" form of this practice  using many different file formats. This practice is similar to Rivest's chaffing and winnowing, but unlike c&w  the adversary in this case will not know this is happening. One physical way to do this is microdots. This includes  jargon codes and semagrams are a form of this based on images or typography. Invisible watermarking is a form of  this action. For 10 points, name this act of hiding a message in a picture or text.
One method for doing this on on 8 by 8 blocks of canonical gray coding is bit plane complexity  segmentation.
steganography [prompt on hidden messages]