【摘要】 理论上混沌具有非周期性,但利用有限精度的数字计算机产生密码系统的伪随机(PR)序列时会出现短周期问题,从而影响了序列的统计性能和密码系统的安全性。为提高伪随机序列的统计性能和解决短周期问题,提出了一个新的自动切换混沌系统,该系统由两个子系统组成,其结构和状态受其自身的伪随机变量控制,并在两个子系统之间自动随机转换。这相当于对一个混沌系统的结构、变量和参数同时随机扰动;也等效于两个混沌系统的混合。利用这种自动切换混沌系统可在数字实现时增大混沌伪随机序列的周期,提高其统计特性和密码系统的安全性。更多还原

【Abstract】 Chaos has theoretical non-periodic property.However,when finite-precision digital computer is used to generate the PR sequence of the crypto system,the problem of short cycle would occur,thus influencing the statistical properties and security of the designed chaotic cryptosystems.To improve the statistical properties of PR sequence and solve the short cycle problem,this paper presents a novel automatic switched chaotic system,which consists of two subsystems and could change its structure and states randomly from one to another under the control of its own PR variable.This is equivalent to randomly and simultaneously perturbing the system variables and parameters,as well as to the mixing of two chaotic systems.By using this system,the cycle length could be prolonged,and the statistical properties and security of cryptosystems enhanced in the realization of digital form.更多还原