An Information Steganography Algorithm Based On Image Chroma Redundancy

With fast development of computer technology , information processing technology, as well as the network communication technology since 1980's, the problem of information safety is more and more necessary. Information hiding as an important technique of information safety, has aroused widely concern in academe and relative department. Steganography and digital watermarking are the main embranchments of information hiding which are extensive investigated now.Steganography makes use of the redundancy in vision, hearing and statistic, and embeds the secret information coded or encrypted into public digital carrier. With the public medium, the hided secret can be transmitted without suspicion and arrive at the aim of privy communication. Aiming at information steganography, steganalysis is advanced fleetly. Steganalysis means using all kinds of statistical analysis methods to post the secret information existing in carrier signal.After researching the knowledge of information steganography and steganalysis to JPEG images, the main work encloses structured an information steganography algorithm based on image chroma redundancy and abecedarian take apart the JPHS tool which include the following three aspects:1. This paper firstly research the concepts of information hiding , information steganography,steganalysis and the JPEG images compression standard,file format,coding process and the usual information steganography method and steganalysis algorithms of JPEG images.2. An information steganography algorithm based on image chroma redundancy is structured. Through analysing the compression process of chroma ponderances C_b,C_r, this paper proposes and realizes an information steganography algorithm based on image chroma redundancy and discusses the secret information embedded and distillation process in details.3. The information steganography tool JPHS has been elementary taken part. After analyzing the data of secret carried image it can be known that JPHS tool doesn't leave identifier information into the secret carried image. And analysis of former JPHS tool provides the embedding method of secret information. After comparing the DCT coefficients of the carrier image and secret carried image, we find the changing principle of DCT coefficient when the secret is embedded. This paper also analyzes the robust of JPHS tool and gets the conclusion that JPHS dosen't possess well robust capability. Our work has made a good basis for latter researchon this project.