The encryption algorithm of finite automata (FA) public key cryptosystem is implemented by a weakly invertible finite automata (WIFA) which is composed of a nonlinear WIFA with delay 0 and a linear WIFA with delay τ....The encryption algorithm of finite automata (FA) public key cryptosystem is implemented by a weakly invertible finite automata (WIFA) which is composed of a nonlinear WIFA with delay 0 and a linear WIFA with delay τ. In this paper, we proved that such an automaton bears the same properties as the linear WIFA and the increasing ranks of the latter are key factors to affecting the former. A probabilistic algorithm is given to realize a ciphertext attack, and its complexity is analysed through the increasing ranks of the linear WIFA. The size of the parameters for safe linear WIFA is estimated.展开更多
文摘The encryption algorithm of finite automata (FA) public key cryptosystem is implemented by a weakly invertible finite automata (WIFA) which is composed of a nonlinear WIFA with delay 0 and a linear WIFA with delay τ. In this paper, we proved that such an automaton bears the same properties as the linear WIFA and the increasing ranks of the latter are key factors to affecting the former. A probabilistic algorithm is given to realize a ciphertext attack, and its complexity is analysed through the increasing ranks of the linear WIFA. The size of the parameters for safe linear WIFA is estimated.
基金国家自然科学基金(the National Natural Science Foundation of China under Grant No.60473005)教育部优秀青年教师资助计划资助项目(No.2002-40)+1 种基金广西科学基金资助项目(No.0575050, No.0640061)广西研究生教育创新计划资助项目( No.2007106020701M51)
基金国家自然科学基金(the National Natural Science Foundation of China under Grant No.60663001)广西省自然科学基金(the Natural Science Foundation of Guangxi Province of China under Grant No.0640061)国家教育部优秀青年教师资助计划(No.2002-40)
