Research On Identity Authentication In CBTC System

Communication Based Train Control (CBTC) can solve effectively many problems of the traditional train control system of track circuits, which is the main direction of future subway signal system. The advantage of WLAN enables its application in CBTC system, but the security issues such as data transmission fault and malicious eavesdropping, etc. cannot be neglected, which restricts the development of domestic CBTC system. Authentication system, as the fundamental safety service, plays a quite important role in CBTC system. Once the authentication system is broken, all safety measures will be useless. Authentication is the most direct defense line of CBTC system. Therefore, it is of great significance to research the Authentication system.Reliable data communications is the base to ensure the safety of the entire system. To ensure the safe and steady communication of data in WLAN, with an in-depth analysis on the theory that WLAN applied to CBTC system and its own identity authentication, the paper performs a deep research into the safety issues of CBTC based on the IEEE802.11 safety standard protocols, especially considers the identity authentication issue between the wireless unit of the train and the wireless network next to the track. According to the needs on data communication security of independently developed CBTC system, the author analyzes the requirements on security, structure and protective measures of the authentication model, summarizes the designing philosophy of authentication scheme of CBTC system. Then the author brings in the Elliptic Curve public key Cryptosystem to replace the traditional public key cryptography, and designs a highly effective authentication Program IAP-CBTC (Identity Authentication Program of CBTC), which both ensures the safety and improves the efficiency of data communication in CBTC system. The validity is proved through simulation software OPNET.The simulation results show that the IAP-CBTC model realized the key negotiation, and the server side and the vehicle wireless unit achieve the mutual authentication. The author simulates the impersonation attacks and middle attack, and IAP-CBTC model can resist these two attacks. The paper receives a single model run time, latency, utilization ratio and values of the three statistical indicators. Finally, it is proved that the authentication scheme designed meets our transport needs of CBTC system security.