Location-based services (LBSs) have gained popularity as a result of the advances in mobile and communication technologies. LBS provide users with relevant information based on their location. In spite of the desirable features provided by LBS, the geographic locations of users are not adequately protected. Location privacy is one of the major challenges in vehicular and mobile networks. In this paper, we analyze the security and privacy requirements for LBS in vehicular and mobile networks. Specifically, this paper covers privacy enhancing technologies and cryptographic approaches that provide location privacy in vehicular and mobile networks. The different approaches proposed in literature are compared and open research areas are identified.

Satellite communications can be used when other communication systems are either destroyed or overloaded. Observation satellites and delay/disruption tolerant networks (DTNs) are technologies that can be interconnected to provide emergency communication for disaster recovery operations. DTNs use a store-carry-forward mechanism to forward messages through intermediary nodes to the destination node. The reliability of relaying messages through multi-hop nodes poses a significant problem in DTNs due to lack of consistent connectivity. These network characteristics make DTNs to heavily rely on the cooperation of neighboring nodes for the successful delivery of packets. However, the presence of malicious or selfish nodes will have a great impact on the network performance. In this paper, we design a decentralized trust management scheme (DTMS) to filter out malicious nodes in DTNs. First, the number of forwarding evidence is combined with the energy consumption rate of the nodes to formulate direct trust. Then, a recommendation trust is computed from the indirect trust, recommendation credibility, and recommendation familiarity. Recommendation credibility and familiarity improve the overall recommendation trust by filtering out dishonest recommendations. A comparative analysis of DTMS is performed against a cooperative watchdog scheme, recommendation based trust model, and spray and wait protocol. The results show that DTMS can effectively deal with malicious behaviors in DTNs including trust related attacks.

As modern vehicle and communication technologies advanced apace, people begin to believe that the Intelligent Transportation System (ITS) would be achievable in one decade. ITS introduces information technology to the transportation infrastructures and aims to improve road safety and traffic efficiency. However, security is still a main concern in vehicular communication systems (VCSs). This can be addressed through secured group broadcast. Therefore, secure key management schemes are considered as a critical technique for network security. In this paper, we propose a framework for providing secure key management within the heterogeneous network. The security managers (SMs) play a key role in the framework by capturing the vehicle departure information, encapsulating block to transport keys and then executing rekeying to vehicles within the same security domain. The first part of this framework is a novel network topology based on a decentralized blockchain structure. The blockchain concept is proposed to simplify the distributed key management in heterogeneous VCS domains. The second part of the framework uses the dynamic transaction collection period to further reduce the key transfer time during vehicles handover. Extensive simulations and analysis show the effectiveness and efficiency of the proposed framework, in which the blockchain structure performs better in term of key transfer time than the structure with a central manager, while the dynamic scheme allows SMs to flexibly fit various traffic levels.