On the security of symmetric ciphers based on DNA coding

The security issues of symmetric ciphers based on DNA coding are studied in this paper. Firstly, ciphers solely based on DNA coding are described. Their operation principle is that a plain bit-string is mapped to a base-string according to a rule selected from eight possible ones. Then the base-string is processed with another secret base-string by one or more DNA operations such as XOR, addition and subtraction. Based on this framework, two basic models are constructed: to code at random or to employ a secret base-string. The security of these two models is analyzed. Secondly, two existing encryption schemes combining DNA coding and chaos theory are considered as the general models. Their security evaluations are presented in detail. It is believed that our security analyses help in the design of secure and efficient cryptosystems based on DNA coding.