School of Computer Science and Technology Harbin Institute of Technology Shenzhen Shenzhen 518055 China;
College of Electrical and Information Engineering Hunan University Changsha 410082 China;
School of Computer Science and Technology Harbin Institute of Technology Shenzhen Shenzhen 518055 China;
Department of Computer and Information Science University of Macau Macau 999078 China;
nonlinear system; chaotic system; field-programmable gate array(FPGA); pseudorandom number generator(PRNG); hardware implementation;