Programmable Design And Implementation Of Time-delay Chaotic True Random Number Generator

With the extensive use of new technologies such as Cloud Computing,Big data,Artificial Intelligence,Blockchain,and the Internet of Things,information security has become more and more important.More secure password protection algorithms are needed to avoid leaking information.The random number generator is the core of cryptography.Therefore,how to obtain a sequence with high randomness has become a topic that is widely concerned by many universities and research institutions.Random number generator includes true random number generator and pseudo random number generator.Compared to pseudo random number generator that uses fixed mathematical algorithm to generate "random sequence",true random number generator uses many kinds of physical processes to generate unpredictable true random sequence.Therefore,true random number generator can be used in places with high security requirement,such as banking system and security chip.With the development of nonlinear theory,chaos provides the new theory and method about generating true random number.Chaos has many unique properties such as internal randomness,infinite period,sensitivity to initial conditions and the unpredictability of long-term behavior.Therefore,chaotic systems are suitable to design true random number generator.Especially time-delayed chaotic systems,they can have multiple positive Lyapunov exponents and generate extremely random and unpredictable time series on a relatively simple structure.However,chaotic circuits usually are designed and implemented with traditional analog circuit design techniques now.And once the circuit is implemented,the circuit parameters and structure are difficult to change,so researchers who study chaotic true random number generators with different structures and parameters need to prepare a large number of electronic devices to redesign,which can be difficult and time-consuming.To solve the above problems,programmable devices are used to design and implement a chaotic true random number generator with time delay,and the positive results have been achieved in the following aspects:FPAA(Field Programmable Analog Array)is used to design and implement time-delay analog chaotic sources.Similar to FPGA(Field Programmable Gate Array),FPAA is also a programmable device.It is different that FPGA implements programmable design of digital circuits,while FPAA can realize the design of various analog circuits by programming.This allows designers to easily modify the design or make the new design.In this paper,a universal method of designing time-delayed chaotic circuits is given by using FPAA.And many design details are introduced by taking using FPAA to design Ikeda system for example.And the time series diagram,bifurcation diagram,phase space diagram,Lyapunov exponent,power spectrum and permutation entropy are used to analyze the dynamics of chaotic sources.Experiments show that using FPAA can easily realize the design of chaotic sources with different parameters and structures.In order to improve the randomness of time-delayed chaotic true random number generator,a self-designed true random number generator based on the variable parameter time-delayed Ikeda system is designed.Experiments show that the Ikeda system with variable delay is more complicated and random than the Ikeda system with fixed delay.And the random sequence outputted by this true random number generator have good randomness and can pass the SP800-22 test,AIS31 test,ENT test and FIPS140-2 test.Besides,the random number generator is realized by FPGA and FPAA,so it's a fully programmable design,which greatly reduces the difficulty of research and shortens time of design.Therefore,it will be of great help to researchers' research on chaotic true random number generators.