Research On Key-insulated Authentication Schemes For VANET

Vehicular ad-hoc network(VANET)is a significant part of the development of intelligent transportation and smart cities.As a huge interactive network that provides convenient and efficient trips,VANET has been successively applied into people's lives.Its impacts on traffic safety and efficiency have been evidently shown and its development is unstoppable.In view of the above-mentioned facts,VANET is closely associated with people so that its security should also not be ignored.To guarantee security,authentication is one of the most essential parts.In order to prevent possible security attacks,quantities of security authentication schemes for VANET have been developed,most of which are based on the hypothesis that the secret key is kept perfectly secure.However,key exposure is inevitable on account of the openness of VANET environment.A great many methods have been put forward to tackle this issue.Balanced all aspects of factors such as computation complexity,security and so on,key insulation becomes a relatively ideal solution.The core idea of key insulation in this thesis is to divide the private key of the vehicle into two parts.An auxiliary is needed to help the vehicle periodically update its secret key so that key leakage in certain time would not influence the entire system security.The mainly finished work of this thesis is displayed as follows:1.A key-insulated security authentication scheme is proposed,which is primarily applicable to the communication between the vehicle and the infrastructure.The vehicle user signs with its own temporary secret key and sends the signature to the road side unit(RSU).Through the private key of RSU and the public key of the vehicle user which are embedded in the scheme,RSU could authenticate the vehicle user successfully.In this scheme,key insulation is introduced to deal with the key exposure problem.Instead of timeconsuming bilinear pairing in existing similar schemes,point multiplication operation and point addition operation based on the elliptic curve are used for the scheme construction.Besides,the scheme fulfills the forward and backward security and resists the replay attack and the man-in-the-middle attack.The security of this scheme is based on the discrete logarithm problem and is proved under the random oracle model.Compared with other similar key-insulated authentication schemes,this scheme achieves a better tradeoff between performance and security.2.A key-insulated deniable authentication scheme is proposed,which is principally suitable for the situation that the service request information of the user is forwarded by the service provider to a third party,leading to the user privacy being exposed.The service provider has the ability to generate the same information as the vehicle user generates,hence the third party could not confirm the source of the message.The exponentiation operation is chiefly used for the scheme construction.Additionally,this scheme achieves anonymity,deniability,traceability,the forward and backward security,which effectively protects the user's privacy.Furthermore,comparatively high efficiency and high security are also provided in the scheme.