In urban vehicular networks, where privacy, especially the location privacy of anonymous vehicles is highly concerned, anonymous verification of vehicles is indispensable. Consequently, an attacker who succeeds in forging multiple hostile identifies can easily launch a Sybil attack, gaining a disproportionately large influence. In this paper, we propose a novel Sybil attack detection mechanism, Footprint, using the trajectories of vehicles for identification while still preserving their location privacy. More specifically, when a vehicle approaches a road-side unit (RSU), it actively demands an authorized message from the RSU as the proof of the appearance time at this RSU.
We design a location-hidden authorized message generation scheme for two objectives: first, RSU signatures on messages are signer ambiguous so that the RSU location information is concealed from the resulted authorized message; second, two authorized messages signed by the same RSU within the same given period of time (temporarily linkable) are recognizable so that they can be used for identification.
With the temporal limitation on the likability of two authorized messages, authorized messages used for long-term identification are prohibited. With this scheme, vehicles can generate a location-hidden trajectory for location-privacy-preserved identification by collecting a consecutive series of authorized messages. Utilizing social relationship among trajectories according to the similarity definition of two trajectories, Footprint can recognize and therefore dismiss “communities” of Sybil trajectories. Rigorous security analysis and extensive trace-driven simulations demonstrate the efficacy of Footprint.
In existing system, hackers easily can act as source node and sends message to destination. Destination receives wrong message from hackers. Destination believes that its correct message from source. Destination receives the wrong information from hackers.
Messages are passed from sender to destination (receiver) without any security. Message header holds source node information which sends the message to receiver. Hackers can easily change that header information and sends to destination.
In this proposed system, hackers can not act as source, because one centralized server is maintaining to check authentication of source. This centralized server is sybilguard. It blacks unauthorized users or hackers. Sybil guard is maintaining source node information and header information of message. It checks the users using those details whether they are attackers or normal user. Hacker’s information has not been transferred to destination. Destination has not been receiving any attacker information.
- Topology Construction
- Node entry
- Message transmission
- Sybil guard