A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Symmetric Cryptography Scheme <s> We investigate how to obtain a balance between privacy and audit requirements in vehicular networks. Challenging the current trend of relying on asymmetric primitives within VANETs, our investigation is a feasibility study of the use of symmetric primitives, resulting in some efficiency improvements of potential value. More specifically, we develop a realistic trust model, and an architecture that supports our solution. In order to ascertain that most users will not find it meaningful to disconnect or disable transponders, we design our solution with several types of user incentives as part of the structure. Examples of resulting features include anonymous toll collection; improved emergency response; and personalized and route-dependent traffic information. <s> BIB001 </s> A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Symmetric Cryptography Scheme <s> Vehicular networks have attracted extensive attentions in recent years for their promises in improving safety and enabling other value-added services. Security and privacy are two integrated issues in the deployment of vehicular networks. Privacy-preserving authentication is a key technique in addressing these two issues. We propose a random keyset based authentication protocol that preserves user privacy under the zero-trust policy, in which no central authority is trusted with the user privacy. We show that the protocol can efficiently authenticate users without compromising their privacy with theoretical analysis. Malicious user identification and key revocation are also described <s> BIB002 </s> A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Symmetric Cryptography Scheme <s> In this paper, we introduce a novel roadside unit (RSU)-aided message authentication scheme named RAISE, which makes RSUs responsible for verifying the authenticity of messages sent from vehicles and for notifying the results back to vehicles. In addition, RAISE adopts the k- anonymity property for preserving user privacy, where a message cannot be associated with a common vehicle. In the case of the absence of an RSU, we further propose a supplementary scheme, where vehicles would cooperatively work to probabilistically verify only a small percentage of these message signatures based on their own computing capacity. Extensive simulations are conducted to validate the proposed scheme. It is demonstrated that RAISE yields a much better performance than previously reported counterparts in terms of message loss ratio (LR) and delay. <s> BIB003 </s> A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Symmetric Cryptography Scheme <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
This authentication-based cryptography is also called private-key cryptography. This scheme utilizes a message authentication code (MAC) to authenticate the messages. By using a shared secret key, sender can generate MAC for each message, and also all nodes in an anonymity set verify the MAC attached with the messages by using that key. Symmetric cryptography is fastest and obtains robust computational efficiency because of a single key. To achieve a high level of reliability and privacy, Choi et al. BIB001 introduced a new method, which can produce high efficiency of privacy by combing symmetric authentication with the short pseudonyms in VANETs. In this method, to generate short-lived pseudonyms, authority need to send the different ID and seed value to each vehicle. Additionally, RSU is capable of verification for MACs because it can share keys with vehicles. Xi et al. BIB002 proposed a random key-set based authentication to maintain user privacy by using a zero-trust policy without having trust of central authority with a user policy. In this method, the anonymity is improved by using independent keys for authentication at neighboring RSUs, and also identifying attackers and key revocation, which have been considered in terms of a practical application. This method is better but requires a large amount of computational cost to handle a zero-trust policy. As we know that, symmetric cryptography-based authentication consists of two major issues. First, the key management system in VANETs is very weak, which can elevate the communication overhead and storage. Second, this technique has a lack of non-repudiation. Therefore, it is difficult to provide authentication to each vehicle. Vijaykumar et al. BIB004 designed a TA to facilitate online services to the customers via VANETs. Therefore, it is vital that the exchanged communication between the TA and VANETs preserving the confidentiality and authentication of messages. Besides that, a dual authentication and key management technique are used to provide a secure transmission of data in the vehicular network. A dual authentication technique offers sufficient security to the vehicle, which can efficiently intercept the malicious vehicles to enter in the VANETs. Lin et al.  introduced a time-efficient and secure vehicular (TSVC) method with privacy preservation. This method is used to significantly reduce the packet consumption without limiting the security requirements. The authentication of the packet is done by a MAC tag, which is attached to each packet. However, it required a fast hash operation to verify each packet. By using this method, the packet overhead is minimized by reducing the signature overhead and its verification latency. The bandwidth utilization decreases with the decline in the number of packets. Rhim et al.  introduced an efficient method for a MAC-based message authentication scheme, but this method cannot tackle and secure against the replay attack and requires a sophisticated algorithm, which was proposed by Taeho et al.  by utilizing an improved MAC authentication scheme for the VANETs' system. Zhang et al. BIB003 presented a new method to authenticate a message by using the roadside unit aided message authentication (RAISE) technique. In this approach, RSU verifies the authentication of messages, which are transmitted from vehicles to notify the results back to vehicles. Instead of verifying the message through a traditional PKI-based scheme, they used the concept of each safety message attached with a MAC. This was generated by the sender by using the secret key and RSU. Then RSU is responsible to verify MACs and circulate the outcomes of message authenticity to other vehicles within their range.