Based On The Scrambling Transformation And To Improve The Lsb Embedding Steganography Algorithms

Information hiding has become a new developing research direction in the domain of information security. It has many applications in many fields, such as copyright protection of digital media, multimedia content authentication, copy management and hidden communication. Steganography and digital watermarking are two main subdisciplines of information hiding. Steganography is the art and science of concealing the very existence of hidden information that is invisible to a possible attacker. A lot of steganography methods have been proposed at present. But meanwhile, there emerged a new art whose goal is to discover and render the hidden message, which is known as steganalysis. There also emerged many steganalysis methods that can detect the hidden information reliably. Such situation puts forward higher request to the security of steganography. As a result, the unti-steganalysis algorithm becomes the focus in the research of steganography.This thesis is focused on steganography algorithm based on two-dimensional Arnold transform and modified LSB embedding scheme. The main content of this thesis is summarized as follows:1. Two modified LSB embedding schemes are proposed. Through analyzing thoroughly the switch rule of pair of values caused by traditional LSB replacement scheme and two steganalysis algorithms which can reliably detect the message embedded by traditional LSB replacement (RS method and SPA method), two modified LSB embedding schemes are proposed and construct the probability model of switch rule between pixel values in the modified scheme. If the LSB of the pixel value is same with the message bit, we keep it unchanged. Otherwise, the pixel value is changed by adaptive ± 1 based on the pixels within the neighborhood of current pixel according to two rules of modifications. So the LSB of the pixel is same with the message. Experimental results show that the proposed method has the same embedding capacity and induces the same distortion to the host image with the traditional LSB replacement scheme. Meanwhile, it is undetectable by RS(Regular Singular) analysis and SPA(sample pair analysis) analysis and the histogram's statistical property is preserved well.2. Based on the study of image scrambling technique, the periodicity and the evaluation criterion of scrambling technique's performance, we point out that the security of steganograohy can be improved by scrambling cover-image. The cover image is scrambled by Arnold transform.3. The steganography system based on Arnold transform and modified LSB embedding isconstructed. In the foundation of scrambling image by Arnold transform, message is embedded by modified LSB embedding. The scrambled stego-image is restored with periodicity of Arnold transform. The embedded message can be extracted from LSBs of scrambled stego-image. The srcambling times is used as the key to control the embedding and extraction of the message, so the security of steganography system is improved.Finally we summarize the research work of the thesis, and prospect the research directions in the future.