A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Performance of Authentication Schemes <s> NS-2, with its IEEE 802.11 support, is a widely utilized simulation tool for wireless communications researchers. However, the current NS-2 distribution code has some significant shortcomings both in the overall architecture and the modeling details of the IEEE 802.11 MAC and PHY modules. This paper presents a completely revised architecture and design for these two modules. The resulting PHY is a full featured generic module able to support any single channel frame-based communications (i.e. it is also able to support non-IEEE 802.11 based MAC). The key features include cumulative SINR computation, preamble and PLCP header processing and capture, and frame body capture. The MAC accurately models the basic IEEE 802.11 CSMA/CA mechanism, as required for credible simulation studies. The newly designed MAC models transmission and reception coordination, backoff management and channel state monitoring in a structured and modular manner. In turn, the contributions of this paper make extending the MAC for protocol researches much easier and provide for a significantly higher level of simulation accuracy. <s> BIB001 </s> A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Performance of Authentication Schemes <s> During the last few years, continuous progresses in wireless communications have opened new research fields in computer networking, aimed at extending data networks connectivity to environments where wired solutions are impracticable. Among these, vehicular traffic is attracting a growing attention from both academia and industry, due to the amount and importance of the related applications, ranging from road safety to traffic control, up to mobile entertainment. Vehicular ad-hoc networks (VANETs) are self-organized networks built up from moving vehicles, and are part of the broader class of mobile ad-hoc networks (MANETs). Because of their peculiar characteristics, VANETs require the definition of specific networking techniques, whose feasibility and performance are usually tested by means of simulation. One of the main challenges posed by VANETs simulations is the faithful characterization of vehicular mobility at both macroscopic and microscopic levels, leading to realistic non-uniform distributions of cars and velocity, and unique connectivity dynamics. In this paper, we first present and describe VanetMobiSim, a freely available generator of realistic vehicular movement traces for networks simulators. Then, VanetMobiSim is validated by illustrating how the interaction between featured macro- and micro-mobility is able to reproduce typical phenomena of vehicular traffic <s> BIB002 </s> A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Performance of Authentication Schemes <s> Advances in mobile networking and information processing technologies have triggered vehicular ad hoc networks (VANETs) for traffic safety and value-added applications. Most efforts have been made to address the security concerns while little work has been done to investigate security and privacy for value-added applications in VANETs. To fill this gap, we propose a secure and privacy-preserving scheme for value-added applications in VANETs; specifically, a vehicular secure and privacy-preserving location-based service (LBS). For each LBS transaction, the scheme provides authentication, integrity and non-repudiation for both the service provider and the vehicle. A vehicle can obtain the service in an anonymous way and hence vehicle privacy is well protected. However, if a vehicle maliciously uses the service, a tracing procedure can be invoked to find the malicious vehicle, thereby efficiently preventing vehicles from abusing the anonymity provided by the system. These features are achieved by efficiently exploiting the available infrastructure of VANETs and without requiring cooperation from other vehicles, which might be reluctant to cooperate or otherwise unavailable. Although public-key cryptosystems are employed as building blocks, no complicated certificate management is required by our system. <s> BIB003 </s> A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Performance of Authentication Schemes <s> Vehicular ad hoc networks (VANETs) are an important communication paradigm in modern-day mobile computing for exchanging live messages regarding traffic congestion, weather conditions, road conditions, and targeted location-based advertisements to improve the driving comfort. In such environments, security and intelligent decision making are two important challenges needed to be addressed. In this paper, a trusted authority (TA) is designed to provide a variety of online premium services to customers through VANETs. Therefore, it is important to maintain the confidentiality and authentication of messages exchanged between the TA and the VANET nodes. Hence, we address the security problem by focusing on the scenario where the TA classifies the users into primary, secondary, and unauthorized users. In this paper, first, we present a dual authentication scheme to provide a high level of security in the vehicle side to effectively prevent the unauthorized vehicles entering into the VANET. Second, we propose a dual group key management scheme to efficiently distribute a group key to a group of users and to update such group keys during the users' join and leave operations. The major advantage of the proposed dual key management is that adding/revoking users in the VANET group can be performed in a computationally efficient manner by updating a small amount of information. The results of the proposed dual authentication and key management scheme are computationally efficient compared with all other existing schemes discussed in literature, and the results are promising. <s> BIB004 </s> A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Performance of Authentication Schemes <s> Existing secure and privacy-preserving schemes for vehicular communications in vehicular ad hoc networks face some challenges, e.g., reducing the dependence on ideal tamper-proof devices, building efficient member revocation mechanisms and avoiding computation and communication bottlenecks. To cope with those challenges, we propose a highly efficient secure and privacy-preserving scheme based on identity-based aggregate signatures. Our scheme enables hierarchical aggregation and batch verification. The individual identity-based signatures generated by different vehicles can be aggregated and verified in a batch. The aggregated signatures can be re-aggregated by a message collector (e.g., traffic management authority). With our hierarchical aggregation technique, we significantly reduce the transmission/storage overhead of the vehicles and other parties. Furthermore, existing batch verification based schemes in vehicular ad hoc networks require vehicles to wait for enough messages to perform a batch verification. In contrast, we assume that vehicles will generate messages (and the corresponding signatures) in certain time spans, so that vehicles only need to wait for a very short period before they can start the batch verification procedure. Simulation shows that a vehicle can verify the received messages with very low latency and fast response. <s> BIB005 </s> A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Performance of Authentication Schemes <s> Providing an efficient anonymous authentication scheme in vehicular ad hoc networks (VANETs) with low computational cost is a challenging issue. Even though, there are some existing schemes to provide anonymous authentication, the existing schemes suffer from high computational cost in the certificate and the signature verification process, which leads to high message loss. Therefore, they fail to meet the necessity of verifying hundreds of messages per second in VANETs. In our scheme, we propose an efficient anonymous authentication scheme to avoid malicious vehicles entering into the VANET. In addition, the proposed scheme offers a conditional tracking mechanism to trace the vehicles or roadside units that abuse the VANET. As a result, our scheme revokes the privacy of misbehaving vehicles to provide conditional privacy in a computationally efficient way through which the VANET entities will be anonymous to each other until they are revoked from the VANET system. Moreover, the proposed scheme is implemented and the performance analysis shows that our scheme is computationally efficient with respect to the certificate and the signature verification process by keeping conditional privacy in VANETs. <s> BIB006 </s> A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Performance of Authentication Schemes <s> Abstract In order to eliminate the complexity associated with managing public key encryption certificates and the drawbacks of identity-based encryption key escrows, the concept of certificateless public key cryptography has been recommended. Further, in specific application areas where the signatures on numerous messages generated by different users need to be compressed, the concept of the aggregate signature is useful. An aggregate signature can not only reduce the cost of verification, but also reduce the length of the signature, which makes it effective in environments constrained by bandwidth and storage. In this paper, we propose a new, efficient, certificateless aggregate signature based on the elliptic curve cryptosystem (ECC), and demonstrate its ability to support conditional privacy preservation. This scheme demonstrates the process of secure communication between vehicles and the infrastructure in vehicular ad hoc networks (VANETs). The proposed scheme not only satisfies privacy requirements (with security analysis), but also achieves lower message overhead than previous schemes. We demonstrate that the performance of our scheme surpasses that of existing authentication schemes for VANETs in terms of computation and communication costs. <s> BIB007
In order to evaluate which algorithm of authentication schemes obtain better results in each category. Several papers have been reviewed related to the authentication schemes. In symmetric cryptography, Reference BIB004 obtained a better result by using a JAVA-based simulator, in which, considering multiple nodes, each node acts as a VANET user. Additionally, the proposed dual key management scheme significantly obtained computationally efficient and secure data transmission. Thus, in symmetric cryptography, this scheme obtains better results as compared to the other competent methods. In asymmetric cryptography, Azees et al. BIB006 introduced the EAAP scheme to avoid malicious users to enter in VANETs. In this approach, Cygwin 1.7.35-15 with the gcc version 4.9.2 was used to evaluate the computational performance of EAAP. The proposed scheme achieved low computational cost by verifying the multiple signatures and certificates in 300 ms as compared to the other competent methods in an asymmetric cryptography scheme. In identity-based signatures, Zhang et al. BIB005 introduced a privacy-preservation scheme based on an identity-based signature. The proposed method used NS-2 BIB001 , VanetMobisim BIB002 , and the cryptography library MIRACL  to evaluate the performance by assuming different degree parameters, and generating the vehicle mobility with the speed ranges from 50 to 60 km/h. This scheme was significantly used to reduce the transmission overhead, and also minimize the vehicle waiting time to initiate the batch verification process. Therefore, this scheme is the best scheme among other competent methods. In a certificateless signature, Cui et al. BIB007 introduced a certificateless signature based on ECC, which can be able to support conditional privacy preservation. Several different parameters have been used to evaluate the performance of this scheme. First, we created a bilinear pairing with a security level of 80 bits. In the system model, two different layers of the vehicular network are considered. The first layer consisted of a vehicle and RSU, and the communication medium between OBUs and RSUs is 5.9 GHz DSRC. The second layer consists of TA and KGC. In this approach, each vehicle transmits a traffic related message in 300 ms, and the total time need to verify more than 650 signatures is less than 300 ms. Thus, it can verify the large number of messages simultaneously. In the proposed method, the message overhead is significantly reduced along with the less computational and transmission cost as compared to the other certificateless signature schemes. For the group signature scheme, Zhang et al. BIB003 introduced a location-based service (LBS) protocol. In order to evaluate the efficiency of the proposed method, this scheme considered LBS and revocation stages. In the simulation, the cryptography tool multiprecision integer and rational arithmetic library (MIRACL)  and MNT curve implement on embedded degree, which is built in C language, are used. In each LBS event, the RSU processes only one pair to decrypt the message, which required 2.17 ms. This approach can protect the identity and privacy of the vehicle by providing the service to the vehicle anonymously. Thus, it can outperform other competent methods.