Vehicular Delay Tolerant Networks (VDTNs) are characterized model of Vehicular Ad Hoc Networks where vehicles disseminate messages through fixed relay nodes placed on roadside by utilizing a store-carry-forward method. In this paper, we propose a secure message delivery protocol for protecting receiver-location privacy in socialspot-based VDTN because location privacy is one of the most important security requirements. To design a simplified protocol, we eliminate the use of conventional pseudonym-based vehicle identification accompanied with a complex pseudonymous certificate management. Instead, we introduce an identity-hidden message indexing which enables a receiver vehicle to query a message whose destination is itself to the socialspot RSU without revealing its identity, and we make use of non-interactive key agreement scheme to establish a secure communication channel between message source and destination vehicles. Furthermore, we demonstrate experimental results to confirm the reduced cryptographic overhead and the effectiveness of privacy preservation for the proposed protocol.

VANET, VDTN, privacy preservation, ID-hidden index, authentication