Image Watermark Encryption Based On Multi-scroll Chaotic System And Its Hardware Implementation

As one of the important components of multimedia information,digital images are efficiently transmitted and shared,but there are problems that violate the legitimate rights and interests of the original authors,such as malicious tampering,arbitrary copying and dissemination without the consent of the original author.In order to ensure the authenticity and integrity of digital information,embedding identification information in its redundancy at different latitudes is an effective information security protection method.In view of the importance of information security protection,this thesis conducts research on digital watermark image encryption based on chaotic system.Firstly,the theory of chaos watermark encryption technology is introduced,the dynamic analysis of chaotic system is carried out,and the hardware circuit is designed,and then an encryption algorithm based on multi-scroll chaotic system is proposed to realize the preprocessing of watermark signal.Finally,based on the chaos encryption algorithm and discrete wavelet transform,a new chaotic digital watermark encryption algorithm is proposed.Experimental results show that the image watermark encryption method of multi-vortex chaotic system designed in this paper still has good anti-interference ability under multiple attack methods.The specific work content of this thesis is as follows:(1)Through literature research,the development process and main methods of digital image information security protection are sorted out,the main methods of digital image information security protection are summarized,and the problems and theoretical research basis of chaotic digital watermark encryption method are introduced in detail,and the main types of image information security attacks and their corresponding evaluation parameters are listed.(2)Implement the chaotic system hardware circuit based on FPGA system design.Euler discretization was performed for multi-scroll chaotic system,TLV5616 was selected as the D/A conversion chip,the timing of the chip was verified by simulation and the IP core was designed.The AX301 was selected as the FPGA development board used in the experiment and the RTL module design was carried out,and the consistency between the oscilloscope observation results and the numerical simulation results of the system showed that the designed hardware circuit could generate chaotic signals.(3)An encryption algorithm based on multi-vortex chaotic system and DNAencoded images is proposed.The digital image is preprocessed by an Arnold transform,and then DNA is performed on the transformed encrypted image to achieve double encryption of the image.The statistical characteristics of ciphertext images indicate that the proposed encryption algorithm has good encryption performance.(4)A new chaotic digital watermarking algorithm is proposed.In the experiment,the gray image Lena was selected as the carrier image,the school emblem was used as the watermark,and the initial value of the chaotic system was used as the key,and the watermark was preprocessed by the DNA encryption algorithm,and embedded in the low-frequency region of the original carrier image on the basis of discrete wavelet transform combined with the singular value decomposition algorithm(DWT-SVD)to realize the whole set of watermarking process of embedding,extraction and detection,and the experimental results show that the chaotic digital watermarking system has high anti-interference ability and robustness.