Design Of Information Hiding Algorithms Based On Text

With the rapid development and in-depth application of the network technology, communication technology and multimedia signal processing, the problem of information security is increasingly salient. As a new cryptographic technique, data hiding becomes a cutting-edge of the multimedia information security area. There is huge text data on the internet and text images scanned from personal document, educational certification and so on, which play a more and more important role in everyday life. Thus,security problems become a crucial issue in information security area, such as storage management, intellectual property protection and content validation.Targeting on the development and application requirements of the text information hiding technology, the bodies of the studies would be outlined as follows:1. Proposing a text hashing based on components of Chinese characters. We split Chinese characters into components by its structure, and propose a text hashing based on components of Chinese characters. It is robust against attacks when used in text zero-watermarking,such as copying,reversing,removing, and synonym substitution, etc, and it performs a strong function when used in information processing.2. Proposing a scheme of digital text watermarking based on LSFR. First, through analyzing text coding and the property of LSFR, a digital text watermarking model based on LSFR is proposed, which applied to single dimensional data. Second, we propose a new method used of embedding information based on space and punctuation. At last, we use the method to embed watermarking message which was produced by the watermarking model in the text. There's no need to change character contents for protecting the authorship, and it doesn't increase bytes of the text. The simulation results show that, any part of the text can recover the watermarking message and has good robustness against attacks.3. Proposing a text image hiding scheme based on block-matching and steganographic codes.(1) Through analyzing the characteristics of text image, we present the concept of semantic robustness, synonymous block and almost synonymous block in text image; and then a conversion algorithm between binary and polynary system is presented, the algorithm has higher conversion efficiency.(2) We use carrier text image to match synonymous block and almost synonymous block for secret text image, and embed the position information of matched block into carrier text image. Then we use the conversion algorithm to switch the position information into plurality codes, which make further improvement on the embedding capacity. We combine some steganographic codes to obtain steganographic codes in any embedding capacities, which could improve the embedding efficiency, i.e. improve the secure performance.The experimental results show that when the scheme is used for hiding text image, the extracted secret text image is similar to the original secret text image. Comparing with some methods with large embedding capacity, the scheme has great improvement on the secure performance and embedding capacity.