In Vehicular Ad Hoc Networks (VANETs), because of high mobility of vehicles and frequent change of road segments, an end-to-end communication path between moving vehicles may not exist unfortunately. As a promising solution to this challenge, for non-realtime constrained VANET applications, store-carry-forward paradigm is considered to deliver a message to a remote destination vehicle effectively through a socialspot in city road environments. So, the behavior of VANET can be modeled as Delay Tolerant Networks, and known as Vehicular Delay Tolerant Networks (VDTNs). Therefore, in this paper, we propose a secure message delivery protocol for protecting receiver-location privacy in socialspot-based VDTNs since location privacy is one of critical security requirements in VANETs. To design a simplified protocol, we eliminate the use of pseudonym-based vehicle identification accompanied with a complex pseudonymous key 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.