Vehicular Ad Hoc Networks (VANETs) are an important component of intelligent transportation systems, enabling real-time communication among vehicles, roadside infrastructure, and transportation services. However, the open and highly dynamic nature of VANETs creates significant security and privacy challenges, including impersonation, Sybil attacks, identity disclosure, pseudonym misuse, unauthorized access, and difficulties in maintaining accountability. These challenges become more complex in vehicle-rental environments, where temporary drivers must be authenticated and authorized without unnecessarily exposing their permanent identities. This review presents a comprehensive analysis of 40 studies on secure and privacy-preserving vehicular communication, with particular emphasis on authentication, conditional privacy, pseudonym management, Sybil resistance, driver accountability, blockchain-assisted security, revocation, and zero-trust authentication. Four closely related studies on privacy-preserving Sybil-free authentication, secure vehicle renting using a zero-trust approach, privacy-preserving vehicle renting with driver accountability, and covert-channel security are examined as central contributions to the research domain. The review shows that conventional authentication mechanisms provide strong identity verification but may expose sensitive user information, whereas pseudonyms, anonymous credentials, conditional privacy-preserving authentication, and zero-knowledge techniques provide stronger privacy while retaining controlled accountability. Blockchain-based and trust-management approaches further address distributed authentication and revocation but introduce additional computational, communication, and scalability considerations. The analysis identifies a significant research gap in integrating privacy-preserving rental authorization, Sybil resistance, temporary credential management, conditional accountability, efficient revocation, and zero-trust principles within a unified VANET framework. Future research should therefore focus on lightweight anonymous credentials, zero-knowledge-based authorization, rental-session-bound pseudonyms, privacy-preserving accountability, and scalable decentralized revocation mechanisms. Such an integrated approach can support secure and privacy-aware vehicle sharing and rental services while maintaining the authentication and accountability requirements of intelligent transportation systems.