Research On Color Image Encryption Algorithm Based On Chaotic System

With the popularity of the Internet, we use digital image everyday and everywhere, and the security ofdigital image transmission is on the prominent, especially when transporting the digital image relatinggovernment, political, military and other sensitive aspects. There are characteristics such as a lot ofinformation, high correlation of adjacent pixels etc in the digital image. As a result, the traditionalencryption algorithms has very weak effects on image encryption because of low speeding and low security.The chaotic system can get the desired results for digital image encryption because it has high randomness,high sensitivity, the basic characteristics of ergodicity.In order to improve the security and speed of the encryption algorithm, this paper which usesthree-dimensional chaotic system, fractional chaotic system, Quantum chaotic system, composite chaoticsequence of multiple system and improved mapping designs and does simulation experiments based onchaotic system of three color image encryption algorithm and obtains the good simulation results. Here arethe main contents:Firstly, based on two three-dimensional chaotic systems and their improved sequences, the paperproposes the first color image encryption algorithm and realizes it from FPGA. The algorithm uses both ofscrambling and multiple rounds of proliferation including Remainder, XOR, addition, multiplication, andother operational methods to ensure the security of encryption algorithm.Secondly, based on comprehensive scrambling and recently proposed fractional-order chaotic system,the paper proposes the second color image encryption algorithm. This algorithm uses fractional orderchaotic system chen to scramble the image locally, then uses the improved logistic mapping to scramble thefull image, and makes use of fractional Lü chaotic system to diffuse the image at last. The algorithmintroduces a fractional order chaotic system and the overall utilization of local scrambling and scrambling,large key space, high security, under the premise of safety, saving time image encryption overhead. Thealgorithm pulls in fractional chaotic system and utilization of local and global scrambling to make sure ithas a large key space, high security as well as the high speed.Finally, the paper proposes the third color image encryption algorithm based on adaptive and composite chaotic system. The algorithm joints both of compression and encryption, which effectively usesmultiple rounds of scrambling, substitution and diffusion in compression and encryption process, globallyscrambles the color image at first, then scrambles the color image in block again, adaptivly encrypts thecolor image through multiple rounds of scrambling and spreading DC coefficients and AC coefficients atlast. The algorithm which compresses the storage space of the image reduces the transfer time and makessure that it is safety.Theoretical analysis and simulation results show that these three algorithms have large enough keyspace, excellent encryption effect, high safety, which can be widely used in secure communication ofmultimedia data.