Research On Image Copyright Protection Technology Based On Chaotic System

With the rapid development of Internet and digital technology,the number of digital products has increased sharply.As an important information carrier,digital images are also widely disseminated and stored in the Internet.However,in the process of dissemination and use,the abuse and tampering of digital images by third parties has caused a large number of piracy and infringement problems.At present,image encryption technology and digital watermarking technology are mainly used to solve the security problems in the process of image transmission and use.This thesis studies the image copyright protection technology based on chaotic system.The main work is as follows:(1)A color image encryption algorithm based on chaotic system and DNA operation is proposed.The algorithm first encrypts the image in blocks according to the three channels of R,G and B.In the encryption process,the chaotic sequence generated by the chaotic system determines the DNA encoding,decoding and operation mode of each image block,then transforms the encryption results again in rows and columns,and finally combines the three channels to obtain the encrypted image.Theoretical analysis and simulation results show that the proposed encryption algorithm has a large key space,can resist exhaustive key attack,statistical analysis attack,information entropy attack and differential attack,and has good anti noise performance and anti clipping performance.(2)A color image watermarking algorithm based on chaotic encryption and DWT is proposed.Firstly,the algorithm uses the method of extracting the pixel mean to obtain the characteristic value of the carrier image.After processing,it is used as the initial value of the chaotic system to encrypt the original watermark image.According to the masking characteristics of human visual system,the coefficients of wavelet and the embedding intensity of watermark are changed,and then the encrypted watermark image is embedded into the if subband of the carrier image according to the resolution and channel.Simulation results show that the proposed watermarking algorithm has good invisibility and robustness,and can effectively resist various types of attacks such as noise,filtering,JPEG compression,clipping,rotation and scaling.