Research Of Image Authentication And Tamper Recovery Algorithm Based On Digital Watermarking

The rapid development of information technology makes multimedia technology become intelligent increasingly.In modern life,digital images,video and audio make life much more convenient.People can easily transfer all kinds of digital information by the ubiquitous Internet.While people enjoy the convenience of digital information,at the same time,some problems such as authenticity,copyright,and security of information come in our eyes.Digital watermarking technology is an effective means to solve the various security problems,and digital watermarking technology has become a hot topic in the field of information security.First,the basic principles of digital watermarking technology is described,and the current status of digital watermarking and typical digital watermarking algorithm are introduced in detail.Then new algorithms are proposed to solve problems in tamper detection and the authenticity of the digital image copyright.For the copyright problem in the digital image,a robustness watermarking algorithm is proposed based on discrete cosine transform and chaotic encryption.After the discrete cosine transform of original image block,meaningful binary image and chaotic sequence are encrypted to generate random location,which is used to modify frequency coefficients in discrete cosine transform to achieve embedded authentication watermark.Experimental results show that the algorithm has good transparency and robustness.It can defend a variety of conventional attacks.For the poor robustness and low accuracy problem of classic tamper localization algorithm.Combination with Singular Value Decomposition,an improved tamper localization watermarking algorithm is proposed.The image feature information(wavelet coefficients)is embedded in the singular value matrix block,which can achieve the tamper localization of 2*2 pixels.Experimental results show that positioning effect of the algorithm is excellent.For the poor safety problem of classic variable-payload recovery watermarking algorithm.An improved variable-payload recovery watermarking algorithm is proposed.The algorithm make an Arnold scramble of the original image,then do texture classification,produce different lengths of variable-payload watermarking.Pseudo random sequence is generated by the secret key.By double encryption with embedded sub-block position and embedded sequence,the watermarking information is embedded.Experimental results show that the algorithm can reach higher safety performances,and can restore the tampered image very well.