The Research And Implementation Of Security Mechanism For Smart Grid DNP3

Smart Grid is an important national critical infrastructure,which utilizes technologies in network information,automatic control and Internet of Things(IoT).Because smart grid gradual switches from centralized management model to open teleoperation mode,its security issues are increasingly prominent,especially in terms of data transfering and resources sharing.Moveover,it also faces viruses,Trojans and other security threats.Distributed Network Protocol(DNP3)is a real-time communication protocol widely used in industrial control systems,which has the characteristics of efficiency,reliablity,flexiblity and standardizition.Since DNP3 did not contain security mechanism in the early design and its data format and message structure is open standards,DNP3 packets may well be intercepted,monitored,and even modified during the transmission,which poses a great security threat for the Smart Grid communication.Therefore,it is of great significance for the construction and development of the Smart Grid to study how to strengthen the DNP3 protocol security and ensure the communication security of Smart Grid.In this paper,we study the security risks and shortcomings of DNP3 and propose a security reinforcement framework.Specifically,by analyzing the structure and security needs in Smart Grid,we design and implement intrusion detection and secure transmission mechanisms to enhanced DNP3 protocol security.In the study of intrusion detection mechanism,this paper presents an intrusion detection method based on DNP3 format analysis.Particularly,on the basis of the Bro framework,the paper designs a DNP3 analyzer,which includes DNP3 parser,DNP3 event handler and DNP3 policy validator.By extracting intrusion behavior features,we define the DNP3 validation policy from three perspectives: DNP3 protocol field,field association and communication mode.Simulations on intrusion detection test bench verify the effectiveness of our intrusion detection method.In the study of secure transmission mechanism,this paper extends the Secure Sockets Layer(SSL)protocol with Elliptic Curve Cryptosystems(ECC)and Advanced Encryption Standard(AES)algorithms to ensure the data security during transmission.The secure transport mechanism consists of two moduels: SSL handshake model and date encryption module.The SSL Handshake module uses two algorithms(ECDSA and ECDH)to achieve signature verification and secret key exchange,which is secure,flexible and efficient.The data encryption module encrypts data by applying the AES algorithm and achieves the verification of data integrity by using the MAC operations.Finally,we use OpenSSL,an open source cryptography library,to implement our modules and test the performance of the secure transport mechanism from several perspectives.Results indicate that our secure transport mechanism can meet the real-time requirements of Smart Grid,and achieve secure transmission and DNP3 protocol security enhancement simultaneously,both of which are of certain practical importance for the industrial systems' security.