Research On Key Technologies Of Information Hiding System For Digital Images

Nowadays,multimedia such as images and videos are easily acquired and multimedia communication via network is an important part of people’s study,life and work.However,the open characteristic of network brings some security problems,such as wiretapping,hijacking,tampering and forgery.How to ensure content security of multimedia has become an important problem of information security.This kind of research has attracted much attention from scholars and experts from academic and industrial domains.This thesis investigates key technologies of information hiding for digital image.The main research contents include image encryption based on double rectangle scanning and chaotic maps,multiple cover images based information hiding for large file,and information hiding software for mobile phone.The results of this thesis enrich the theory and technology of image information security,and provide a practical software for mobile phone.The results have important theoretical value and practical significance.This thesis introduces research background of image information security and developments of image encryption and information hiding,and then exploits random overlapping blocking,double rectangle scanning and chaotic theory to design an efficient image encryption algorithm.Meanwhile,aiming at the application of hiding large file,this thesis designs a multiple cover images based information hiding method and a software for mobile phone.The main results of this thesis are as follows.1.Image encryption based on double rectangle scanning and chaotic maps is proposed.This thesis combines random overlapping blocking,double rectangle scanning,Henon chaotic map and Lu chaotic map to design efficient image encryption algorithm.Specifically,input image is first divided into overlapping blocks and each block is scrambled via double rectangle scanning.During the scanning,the beginning point is randomly selected under the control of Henon chaotic map for enhancing security.Next,image content based secret keys are generated and used to control the Lu chaotic map for generating a secret matrix with the same size of input image.Finally,the encrypted image is obtained by calculating XOR operation between the corresponding elements of the scrambled image and secret matrix.Experimental results show that the proposed algorithm has good encrypted results and a fast speed,and is better than several reported encryption algorithms.2.Multiple cover images based information hiding method and a software for mobile phone are designed.Aiming at the real application of hiding large file,this thesis designs a multiple cover images based information hiding method.This method calculates the bit number embedded to each cover image and divides large file into several sub-files in terms of the volume of large file,the number of cover images and their file sizes.To ensure correct extraction,additional file header data is generated for each sub-file,including hash value of secret key,serial number of sub-file,volume of sub-file and so on.During data embedding,the technique of the least significant bit(LSB)matching is exploited to embed file header data and sub-file data into the corresponding cover image.Based on the core technology of multiple cover images based information hiding method and double rectangle scanning based image encryption,this thesis designs and implements an image information hiding system for mobile phone under the Android development platform.This software includes the functions of image encryption,image decryption,image information hiding and extraction.Experiments validates the correctness and effectiveness of this software.