Lightweight Privacy-Preserving Authentication Scheme for V2G Networks in the Smart Grid Neetesh Saxena, Bong Jun Choi, and Shinyoung Cho Department of Computer Science The State University of New York, Korea & Stony Brook University, USA Email: mr.neetesh.saxena@ieee.org, {bjchoi, sycho}@sunykorea.ac.kr Abstract—Vehicle-to-grid (V2G) is one of the future key technologies for the smart grid. Electric vehicles (EV) are potential power consumers that can play a crucial role by delivering the power back to the grid in order to meet the power demand. However, the V2G network has some crucial security and privacy challenges. Also the existing solutions generate a huge overhead cost and do not provide resistance against well known security attacks. In order to address the identified security and privacy challenges in the V2G smart grid network. We propose a scheme based on bilinear pairing technique with an accumulator that provides mutual authentication, and privacy preservation of EV’s information such as identity, battery status, location, and charging/discharging selection and time duration. The proposed scheme defeats various security attacks, including man-in-the-middle attack, replay attack, impersonation attack, redirection attack, and repudiation attack while generating lower communication and computation overhead than existing privacy- preserving V 2G mutual authentication schemes. Keywords—authentication, bilinear pairing, privacy-preserving, security attacks, V2G; I. I NTRODUCTION In the future, Vehicle-to-Grid (V 2G) system is proposed to be one of the most powerful system in the smart grid by integrating with renewable energy sources to provide ancillary services and keeps track of the power demand utilized by the Electric Vehicles (EV )/Battery Vehicles (BV ). These vehicles communicate with the smart grid for charging and discharging the battery by consuming the power from the grid and delivering the power back to the grid, respectively. A Ded- icated Short Range Communication (DSRC), an automotive standard protocol specifically designed for Vehicle-to-Vehicle (V 2V ) and Vehicle-to-Infrastructure (V 2I ) support, includes IEEE 802.11p and IEEE 1609 Wireless Access in Vehicular Environments (W AV E) [1]. V2G communication system is different from other existing communication systems in several aspects such as vehicle mobility, geographical location of the vehicle, charging and discharging operations, driving pattern, limited communication range, and etc. Further, the V 2G system requires fast authenti- cation as in the future a large number of EV s will participate in charging/discharging process [2]. Moreover, confidential information in V 2G, V 2V , and V 2I such as vehicle identity, vehicle type, charging and discharging time, and charging station identity needs to be protected over the network. The charging and discharging operations also depend upon the type of vehicle and their batteries. It takes almost 10 hours to charge a 15-kWh battery using a standard 120-volt outlet [3]. A. Security Requirements in the V 2G Network There are various security requirements in the V 2G smart grid network as follows. 1) Mutual Authentication: Mutual authentication is one of the mandatory requirements for an authentication scheme so that it can defeat the redirection and impersonation attacks. In V 2G networks, the EV should be able to verify the Local Aggregator (LAG) and the EV must be authenticated by the LAG before the communication starts. 2) Information Confidentiality and Integrity: The secret information sent over the network should be well protected and only the respective recipient should be able to extract that information. Also, the integrity of each message sent over the network must be maintained. This can be achieved using a well known Hash (H)/Message Authentication Code (MAC). B. Privacy Requirements in the V 2G Network There are also privacy requirements in the V 2G smart grid network whenever an EV accesses the charging station for charging/discharging operation. 1)Vehicle’s Location, Battery, and Personal Information: The vehicle’s private information should not be revealed during the authentication. For example, the LAG should not be able to retrieve the location of the EV making a request. The protection of location information also helps to prevent redirection attacks. Similarly, the LAG must not be able to track the EV based on its battery status. The required information should directly be sent to the intended recipient in a secure manner. 2) Vehicle Selections and Operations: The LAG must be unaware of the EV ’s timing selection and the choice of operation when charging/discharging. Similarly, the LAG must not be able to track the EV based on other similar information such as Charging Station Identity (CSID). C. Research Problem EV s perform charging and discharging operations in order to meet their energy demand and to balance the power in the grid. However, there exist various security and privacy challenges in the V 2G system as stated above. The information shared by the EV s and other V 2G entities such as Aggrega- tor (AG), Certification/Registration Authority (CA/RA), and Control Center (CC) must be secured over the network and the privacy of the information must be maintained. The V 2G 2015 IEEE Trustcom/BigDataSE/ISPA 978-1-4673-7952-6/15 $31.00 © 2015 IEEE DOI 10.1109/Trustcom-BigDataSe-ISPA.2015.425 604 2015 IEEE Trustcom/BigDataSE/ISPA 978-1-4673-7952-6/15 $31.00 © 2015 IEEE DOI 10.1109/Trustcom.2015.425 604