Steganography is the practice of representing information within another message or physical object, in such a manner that the presence of the information is not evident to human inspection. In computing/electronic contexts, a computer file, message, image, or video is concealed within another file, message, image, or video. The word steganography comes from Greek steganographia, which combines the words steganós, meaning "covered or concealed", and -graphia meaning "writing".
1. The word "Wikipedia" is drawn using computer software
Yellow dots from a laser printer
In computing, a computer file is a resource for recording data on a computer storage device, primarily identified by its filename. Just as words can be written on paper, so too can data be written to a computer file. Files can be shared with and transferred between computers and mobile devices via removable media, networks, or the Internet.
A punched card file
The twin disk files of an IBM 305 system
Original JPEG file
Corrupted JPEG file, with a single bit flipped (turned from 0 to 1, or vice versa)