Study On Several Algorithms Of Information Hiding And Restore

With the development of network, communication and information processing, there is a significant development in information hiding which is a new technology of information security. The secret information was hiden in host information, such as, digital image, digital video and digital audio. Information hiding can be divided into two branchs: digital watermark and stenography. It has a broad prospect in covert communication and copyright protection. The technology of digital image scrambling is a supplement of image information hiding, and it comes from the techonology of encrypt. This paper proposes an image scrambling algorithm and three information hiding algorithms based on discrete wavelet transform (DWT) and singular value decomposition (SVD). The major work involved is as follows:1. An image scrambling algorithm is proposed, which is based on the knight-patrol-algorithm. The knight-patrol-algorithm can hide the details of image, but it can not hide the details which has large contour. So this paper proposes a new image scrambling algorithm which can hide more details of image. The results of experiment indicate that it is feasible.2. An algorithm based on discrete wavelet transform (DWT) is proposed, which hides secret information in middle frequency coefficient. The algorithm makes the middle frequency coefficient of the host information into sequence of . If a>b, then represent 1;if a represent 0. The result of experiment indicates that the algorithm is feasible and robust. And the algorithm can be applied in video.3. An algorithm based on discrete wavelet transform (DWT) is proposed, which hides secret information in low frequency coefficient. First, the matrix of the low frequency coefficient is made into the sequence of the 3-by-3 matrix. And the difference between the center coefficients of the little matrix and the average of the little matrix's neighbourhood coefficients is calculated, then the secret information isembed in host information by quantized the difference. The results of experimentindicate that the algorithm is feasible and robust.4. An algorithm based on singular value decomposition (SVD) is proposed, which hides secret information in singular value vector. The singular value vector is the inherent character of matrix;it can improve the robust of the algorithm that hides secret information in singular value vector.