Research On Digital Steganography Technology For JPEG Images

Digital steganography technology which started in the mid1990s has gradually taken thegovernments around the world and research institute’s attention. Digital steganography is animportant branch of information hiding technology. And when transferring data in the publicchannel， secret information is hid in public transmission medium (photos and video andaudio， etc) with a certain steganography algorithm. Digital steganography for JPEGimages refers to that the secret information hiding in JPEG images is to be conveyed. JPEGimages are widely used in daily life for its high compression rate and better visual effect.Therefore， digital steganography research for the JPEG images is very necessary andapplicable.The main contents of this paper are as follows：(1) It introduces the information hiding technology and the definition of digitalsteganography，reviews of digital steganography history,and makes an analysis of recent years’typical steganography algorithms.(2) The spatial domain steganography algorithm of LSB is introduced in detail， andsimulation experiment is carried out on LSB; and four kinds of methods of steganographyanalysis are also introduced in this paper such as the analysis of χ~2, the analysis of estimatedhiding capacity, the analysis of RS and the analysis of GPC.(3) It introduces the compression principle of JPEG image and the principle of digitalsteganography for JPEG image.And it introduces digital steganography methods (JPEG-Jsteg，F3， F4， and F5，etc) based on the JPEG images，and made a simulation experiment for eachsteganography algorithm and summarized their advantages and disadvantages.(4) This paper proposes an improved steganography algorithm for JPEG image based onthreshold.The improved algorithm makes parts of coefficients of0could carry secretinformation by choosing a reasonable threshold and make a mutul complementation of0and1.Therefore， the new scheme could largely improved the embedding rate of secret informationand has high security. Lastly， we reached the goal by the simulation experiment.