In addition, limited autonomy and Latin automata array, the relative of the canonical form for one-key cryptosystem based on limited automata, are also discussed. Until automata considered a natural model for the cipher. The Ra Rb transformation method is introduced to deal with structural problems such automata, then public key cryptography based on canonical forms of automata and limited to one-key ciphers are implemented by automata to the limited propagation - a mistake and without the proposed expansion of the data. This book can be used as a reference for computer science and mathematics majors, including seniors and graduate students. Tao Renji is a Professor at the Institute of Software, Chinese Academy of Sciences, Beijing.