Research On Cross-Domain Information Sharing Security Mechanism Based On Blockchain For VANETs

With the continuous emergence of various application scenarios in vehicular ad hoc networks(VANETs),there is an increasing demand for large-scale and even city level information sharing,which is expanded from the original single domain information sharing service to cross-domain information service.For example,dynamic information such as traffic accidents and road guidance needs to be shared to target vehicles in a wider area to realize cross-domain information sharing.Therefore,it is an important research direction to realize cross-domain information security sharing based on the distributed architecture and multiple security domain management in VANETs.As a distributed trusted infrastructure,blockchain is very consistent with the characteristics of the distributed architecture in VANETs.Therefore,this thesis will study the cross-domain information sharing security mechanism based on blockchain in VANETs.The specific research contents are as follows.1.In order to solve the problem that the key can not be trusted and synchronized in time in the process of cross-domain information sharing,this thesis proposes a distributed key management mechanism for cross-domain information sharing in VANETs.TAs are used as blockchain nodes to build a decentralized key management architecture to realize the decentralized storage of system public key and vehicle public key.We design smart contracts to query,update,and revocate keys on the blockchain,which can improve the efficiency of traditional key management,enhance key management security,and provide important support for subsequent cross-domain message authentication and cross-domain information security sharing.2.In order to ensure the timeliness and security of cross domain information sharing,we design an anonymous traceable cross domain message authentication scheme based on the proposed key management architecture.Through identity based signature(IBS)technology and pseudonym technology,vehicles can authenticate messages from different security domains,eliminating the frequent communication overhead between TAs in traditional cross-domain authentication.We track malicious vehicles through the information on the blockchain to realize the conditional privacy protection of vehicles.In addition,aiming at the additional authentication delay caused by receiving multiple messages from different security domains at the same time,we propose a cross-domain batch message authentication scheme to ensure the timeliness of large-scale and high-frequency cross-domain message authentication.3.Aiming at the problems of mutual trust and high delay of information sharing caused by the lack of open and transparent information interaction environment in the traditional centralized information sharing model,and in order to ensure the confidentiality and controllability for diversified information sharing,we propose a cross domain information sharing scheme based on attribute based encryption(ABE),in which the information shared by vehicles is distributed and stored on the blockchain constructed by multiple TAs to ensure the timely synchronization of information between different security domains.When the vehicle wants to access cross-domain information,TA generates private keys and attribute keys for vehicles in different security domains based on the key with blockchain,and performs outsourcing decryption for vehicles requiring real-time information services to ensure that vehicles can enjoy cross-domain information services safely and timely.