Vehicular ad hoc networks (VANETs) adopt the Public Key Infrastructure (PKI) and Certificate Revocation Lists (CRLs) for their security. In any PKI system, the authentication of a received message is performed by checking if the certificate of the sender is included in the current CRL, and verifying the authenticity of the certificate and signature of the sender. In this paper, we propose an Expedite Message Authentication Protocol (EMAP) for VANETs, which replaces the time-consuming CRL checking process by an efficient revocation checking process. The revocation check process in EMAP uses a keyed Hash Message Authentication Code ({HMAC}), where the key used in calculating the {HMAC} is shared only between nonrevoked On-Board Units (OBUs). In addition, EMAP uses a novel probabilistic key distribution, which enables nonrevoked OBUs to securely share and update a secret key. EMAP can significantly decrease the message loss ratio due to the message verification delay compared with the conventional authentication methods employing CRL. By conducting security analysis and performance evaluation, EMAP is demonstrated to be secure and efficient.

In this paper, we investigate the effects of routing loop, sinkhole, and wormhole attacks on the position-based routing (PBR) in vehicular ad hoc networks (VANETs). We also introduce a new attack termed wormhole-aided sybil attack on PBR. Our study shows that the wormhole-aided sybil attack has the worst impact on the packet delivery in PBR. To ensure the reliability of PBR in VANETs, we propose a set of plausibility checks that can mitigate the impact of these PBR attacks. The proposed plausibility checks do not require adding extra hardware to the vehicles. In addition, they can adapt to different road characteristics and traffic conditions. Simulation results are given to demonstrate that the proposed plausibility checks are able to efficiently mitigate the impact of the previously mentioned PBR attacks.

Network coding provides a promising alternative to traditional store-and-forward transmission paradigm. However, due to its information-mixing nature, network coding is notoriously susceptible to pollution attacks: a single polluted packet can end up corrupting bunches of good ones. Existing authentication mechanisms either incur high computation/bandwidth overheads, or cannot resist the tag pollution proposed recently. This paper presents a novel idea termed “padding for orthogonality” for network coding authentication. Inspired by it, we design a public-key based signature scheme and a symmetric-key based MAC scheme, which can both effectively contain pollution attacks at forwarders. In particular, we combine them to propose a unified scheme termed MacSig, the first hybrid-key cryptographic approach to network coding authentication. It can thwart both normal pollution and tag pollution attacks in an efficient way. Simulative results show that our MacSig scheme has a low bandwidth overhead, and a verification process 2–4 times faster than typical signature-based solutions in some circumstances.

In this paper, we propose an efficient security scheme for position-based routing (ESPR) in vehicular ad hoc networks (VANETs). The ESPR scheme considers both digital signature and keyed Hash Message Authentication Code (HMAC), where the key used in calculating the HMAC is shared only between unrevoked On-Board Units (OBUs). In addition, the ESPR scheme uses a novel probabilistic key distribution, which enables unrevoked OBUs to securely share and update a secret key. By conducting security analysis and performance evaluation, the ESPR scheme is demonstrated to outperform its counterparts in terms of communication overhead and delay while achieving robust and secure operation.

In this paper, we propose an efficient group signature scheme supporting batch verification for securing vehicular networks. Through analytical and simulation evaluations, we demonstrate that the currently available group signature schemes may not be suitable for vehicular networks due to the highly imposed security overhead. The proposed scheme can mitigate the effect of the heavy security overhead by batch group signature verification. Furthermore, the proposed scheme not only enables vehicles to verify a large number of messages in a timely manner, but also improves the system performance in terms of the message loss ratio.

To achieve high safety levels in vehicular ad-hoc networks (VANETs), the Dedicated Short Range Communication (DSRC) implies each vehicle to periodically broadcast a safety beacon message. Many safety-related applications in VANET are based on the safety beacon messages. To ensure secure communications, the message authentication and integrity must be verified by respectively verifying the public key certificate and the digital signature of the sender. Since each vehicle could receive a large number of messages from the neighboring vehicles, one of the inevitable VANET challenges is the ability for each vehicle to verify a large number of messages in a timely manner. In this paper, we propose an aggregate signatures and certificates (ASIC) verification scheme enabling each vehicle to simultaneously verify not only the signatures but also the certificates of the senders. ASIC significantly increases the vehicle capability to verify a large number of signatures and certificates in a timely manner. Performance evaluation demonstrates that ASIC is reliable, efficient, and scalable.

Vehicular ad hoc networks (VANETs) adopt the public key infrastructure (PKI) and certificate revocation lists (CRLs) to reliably secure the network. In any PKI system, the authentication of a received message is performed by checking that the certificate of the sender is not included in the current CRL, and verifying the authenticity of the certificate and signature of the sender. In this paper, we propose a message authentication acceleration (MAAC) protocol for VANETs, which replaces the time-consuming CRL checking process by an efficient revocation check process. The revocation check process uses a keyed hash message authentication code (HMAC), where the key used in calculating the HMAC is shared only between non-revoked on-board units (OBUs). In addition, the MAAC protocol uses a novel probabilistic key distribution, which enables non-revoked OBUs to securely share and update a secret key. By conducting security analysis and performance evaluation, the MAAC protocol is demonstrated to be secure and efficient.

In this paper, we propose an Efficient Certificate Management scheme for Vehicular networks (ECMV). The proposed scheme offers a flexible interoperability for certificate management in different administrative authorities, and an efficient way for any On-Board Units (OBUs) to update its certificate anywhere at anytime. In addition, an efficient time-limited certificate revocation for OBUs is introduced. It is demonstrated that the ECMV scheme can decrease the complexity of certificate management, and achieves excellent security and efficiency for vehicular communications.

Vehicular communications (VC) have many applications with multicast nature such as cooperative driving and platooning. The multicast nature implies that secure group communication is important to guarantee the security in vehicular networks. One of the main security concerns for vehicular networks is preserving the privacy of the network users. In this paper, we propose privacy preserving group communication protocol for vehicular ad hoc networks (PPGCV). The PPGCV preserves the privacy of the users and provides conditional full statelessness property. By conducting detailed analysis and simulation, PPGCV is demonstrated to be reliable, efficient, and scalable.