steganography

Steganography deals with the discreet hiding of messages within digital objects, such as text, graphics, videos, or photographs. Unlike modern cryptology, where the ciphered message is recognized as such, in steganography the information is hidden in a carrier message, where the carrier message may only be slightly altered, but the hidden message should not be corrupted. This information can be hidden in an audio file, but also in a graphic, a video or a text file.

In order not to falsify the carrier information recognizably, only the bits with the lowest valence are used for the encrypted message in steganography. Such changes are not perceptible or detectable in an audio or graphic file. By using the least significant bits, the encrypted file size is limited. For example, if a bit with the lowest valence is used for the encrypted signal in an SVGA graphic with a resolution of 800 x 600 pixels and 8-bitcolor depth, exactly 60 kB could be transmitted in this image.

For the transmission, the information to be hidden is inserted into a corresponding file - for example a photo - using steganography software by changing certain pixels. The recipient opens the file with the identical steganography software that recognizes the changed pixels and can read the hidden information.

Steganography is also used in digital watermarks, among other things, to detect and prevent the illegal marketing or exchange of music or video sequences on file-sharing networks.