Research On The Security And Capacity Of Steganography Based On Digital Images

Steganography is a new technology in the field of information security. The theories such as security and capacity of Steganography which have not been quite perfect are the primary factor controlling the spread and application of Steganography, so it is a problem to have to be resolved immediately in this field. The research on the security and capacity of Steganography could supply a theoretic guidance for the designer to plan and develop a secure and effective Steganographic arithmetic, and then impel the development and application of Steganography.This paper went deep into the security and capacity of Steganography based on the digital images along the foreland of the research on Steganography. Following fruits have been accomplished independently:(1)A universal model of Steganography was brought forward and formalized., then the security and capacity of Steganography system was definited.(2)The classical theoretical-security model based on the theory of hypothesis and proof-test proposed by Cristian Cachin was improved by restricting the change of the visual and statistical characteristics of the carriers during the process of embedding , and then a theoretical-security model of Steganography based on digital images was established through analyzing the specific characteristics of digital images and wiping off correlation of its pixels;At last, a method based on theoretical security model that quantificationally evaluated the concealment of Steganography was brought forward, which was satisfied the sightless request both from view and statistics.(3) The capacity caculated model resticted by the theoretical-security conditions above was given out by improving the countermeasure model of capacity proposed by P.Moulin which can express the essential of capacity, and then a non-line optimization model of capacity root in the above model refered to was constituted for its easier application by analyzing the property of the countermeasure model of capacity, in the same way the expression of digital images' capacity was gained.(4)In the help of the above fruits, the maximal information can be embeded into a digital images was computed under the precondition that the typical statistical characteristics of the digital image was identical, and then the corresponding best embedding strategy was given out.At last, to prospect the developing foreground of the research in the field of Steganography.