Uses of Steganography
Steganography is a means of storing information in a way that hides that information’s existence. Paired with existing communication methods, steganography can be used to carry out hidden exchanges. Governments are interested in two types of hidden communications: those that support national security and those that do not. Digital steganography provides vast potential for both types. Businesses may have similar concerns regarding trade secrets or new product information. Avoiding communication in well-known forms greatly reduces the risk of information being leaked in transit.
Images as Carriers
Images are a good medium for hiding data (for details, see Pan, Chen, and Tseng 3 ). The more detailed an image, the fewer constraints there are on how much data it can hide before it becomes suspect. The JPHide/JPSeek package (http://linux01.gwdg.de/~alatham/stego.html) uses the coefficients in a JPEG to hide information. A newer method (http://www.know.comp.kyutech.ac.jp/BPCSe/BPCSe-principle.html) embeds data in visually insignificant parts of an image. Both of these methods alter the image; however, you can explore image degradation using different images and messages of varying length. An alternative, specific to GIF images, is to manipulate an image’s palette in order to hide data. Gifshuffle (http://www.darkside.com.au/gifshuffle/) does not alter the image itself in any visible way; rather, it permutes a GIF image’s color map, leaving the original image completely intact
Here is the matlab code for stegnography . both encode and decode
download it from github https://github.com/ebine/stegnography/