一种基于Rule30+细胞自动机的流密码设计方法  

An Efficient Stream Cipher Design Based on Rule30+ Cellular Automaton

作　　者：郭晓威 郭亚军[1] GUO Xiao-Wei;GUO Ya-Jun(School of Computer,Central China Normal University,Wuhan 430079,China)

机构地区：[1]华中师范大学计算机学院,武汉430079

出　　处：《密码学报》2020年第4期439-452,共14页Journal of Cryptologic Research

基　　金：国家自然科学基金(61772224);中央高校基本科研业务费(CCNU19ZN008)。

摘　　要：细胞自动机是一种常见的用来设计随机数发生器和流密码的方法,目前许多流密码的设计都直接或是间接的使用了这种方法.由S.Wolfram提出的,使用Rule30细胞自动机生成伪随机序列的方法是一种经典的基于非线型细胞自动机设计流密码的思路.它具有硬件开销较小,密钥流随机性良好的特点,由于存在不可避免的线性相关性问题,无法满足现代密码学对安全性的要求.本文提出一种新的规则Rule30+,并给出一种基于Rule30+细胞自动机的流密码设计.该细胞自动机能够解决线性相关性问题,流密码的结构属于Grain Family,这种结构包含线性模块,非线性模块和输出函数,并且很契合细胞自动机并行执行,相邻依赖的特性.本文提出的流密码支持任意长度的密钥,在本文中,我们选取的密钥(Key)长度为128比特,初始化向量(IV)的长度为112比特.流密码产生的密钥流具有良好的随机性质,同时具有较小的硬件开销.Cellular automata(CA)is a common method used to design random number generators and stream ciphers.At present,many stream cipher are designed by using this method directly or indirectly.The reason for CA to be chosen in designing stream ciphers is that the hardware implementation of CA is very simple and has parallel characteristics,hence the designed stream ciphers can generate key stream efficiently.Among the existing methods,the method of generating pseudorandom sequences using Rule30 CA proposed by S.Wolfram is a classical idea of designing stream ciphers based on CA.The Rule30 CA is a non-linear CA with less hardware overhead and can generate key streams with good randomness.However,due to the inevitable linear correlation in Rule30,its design does not meet the needs of modern cryptography.This paper presents a new rule called Rule30+,and presents a stream cipher design based on the proposed Rule30+CA.This CA can solve the problem of linear correlation.The structure of stream cipher design belongs to Grain Family which includes linear module,non-linear module and output function.It fits well with the parallel execution and adjacent dependence of CA.The stream cipher support any size of key length.This paper chooses 128-bit key and 112-bit initialization vector(IV).The design is simple and the key stream generated by the proposed stream cipher has good randomness.

关 键 词：流密码 细胞自动机 Rule30 

分 类 号：TP309.7[自动化与计算机技术—计算机系统结构]