Abstract and history

Abstract and history

Abstract

For years, people have devised different techniques for encrypting data while others have attempted to breakthese encrypted codes. For our project we decided to put our wealth of DSP knowledge to use in the art of steganography. Steganographyis a technique that allows one to hide binary data within an image while adding few noticeable changes. Technological advancementsover the past decade or so have brought terms like“mp3,”“jpeg,”and“mpeg”into our everyday vocabulary. These lossy compression techniques lend themselves perfectly for hiding data. We havechosen this project because it gives a chance to study several various aspects of DSP. First, we devised our own compressiontechnique which we loosely based off jpeg. There have been many steganographic techniques created so far, which compelled us tocreate two of our own strategies for hiding data in the images we compress. Our first method, zero hiding, adds the binary data intothe DCT coefficients dropped in compression. Our other method, which we called bit-o-steg, uses a key to change the values ofcoefficients that remain after compression. Finally, we had to find ways to analyze the success of our data hiding strategies, sothrough our research we found both DSP and statistical methods to qualitatively measure our work.

A brief history of steganography

Steganography, or“hidden writing”can be traced back to 440 BC in ancient Greece. Often they would write amessage on a wooden panel, cover it in wax, and then write a message on the wax. These wax tablets were already used as writingutensils, so the hiding of a message in a commonly used device draws very little suspicion. In addition to use by the Greeks, thepractice of steganography was utilized by spies in World War II. There were even rumors that terrorists made use of steganographyearly in 2001 to plan the attacks of September 11