Research On Chaotic Random Number Generator

Due to the rapid popularization of the Internet,electronic payment and other technologies have entered our lives and become an important part of the information age.The illegal use and leakage of privacy data often occur,causing huge economic losses,which has aroused people's great attention.Cryptographic technology is an effective tool to ensure data security,and the random numbers that used in the security system play an important role.When the random number generator produces high quality random numbers,it can provide a secure foundation for the security system.Therefore,how to construct efficient and safe random number generator has far-reaching research value.In recent years,chaos with the characteristics of randomness,unpredictability and ergodicity has become an important tool for constructing random number generators.Based on the characteristics of low-dimensional chaotic system and high-dimensional chaotic system,this thesis designs two schemes for generating random numbers,the main work is as follows:Firstly,because of its simple structure,the low-dimensional chaotic system will degenerate.In order to overcome the degeneration of chaotic system,this thesis proposes a new method to generate random numbers based on low-dimensional chaotic systems.In this method,multiple one-dimensional Logistic chaotic systems are used to dynamically group the chaotic systems with random control parameters.At last,XOR operation is carried out on the generated random numbers to improve the performance of the output random numbers.The random numbers generated by this method is tested by simulation on software.The test results show that the random numbers generated by this method completely pass the standard for randomness of NIST SP800-22,which indicates that the random numbers generated by this method have good performance.In addition,the random numbers generated by this method are applied to image encryption,and it is verified from the aspects of image information entropy,histogram,correlation and differential attack that the generated random numbers used in image encryption can well cover up the distribution of original image information and have high practicability.Secondly,the chaotic characteristics of high-dimensional system are complex and random.Therefore,this thesis constructs a random number generator based on the classical Lorenz chaotic system.Hilbert transform is used to perturb Lorenz chaotic system,and finally a 24-bit random number is generated.Through experimental simulation,the random numbers generated by Lorenz chaotic system proposed in this thesis have good performance,and completely pass various tests of randomness detection.The random numbers generated by this method are applied to information hiding and digital watermarking respectively.Simulation results show that the information hiding algorithm and digital watermarking generation algorithm have better performance and the original image of hidden information is evenly distributed.In this thesis,two methods of constructing random number generator are implemented,and the randomness of the generated numbers is tested strictly.The randomness of the generated random numbers is simulated from different application angles,which provides a reference for the design and application of the random number generator.