Security Analysis and Improvement of Modbus Message in Distribution Network Based on SM9

In order to ensure the information security in smart distribution network, more and more cryptographic algorithms are applied in the communication process. by SM2-based Modbus message security of distribution network was analyzed to find out such defects as its vulnerability to replay attack and tampering attack, and several other description errors. In order to improve this method, the authors in this paper propose a SM9-based protocol of identification algorithm suitable for Modbus TCP (transmission control protocol) message. At first, the process of SM9 digital signature is introduced, and then it is applied to Modbus TCP message communication added with the timestamp mechanism. And the security of the improved protocol is analyzed. Finally, the C language is used to realize the signature scheme, and its efficiency is compared with several other signature schemes. The results show that the improved protocol can not only resist replay attacks and tamper attacks, and ensure the data integrity and source reliability in the process of message communication, but also have a good advantage in running efficiency.