This paper addresses the security challenges in vehicular ad hoc networks (VANETs), which are expected to become the most relevant form of mobile ad hoc networks due to the increasing integration of vehicles with communication capabilities. The authors provide a detailed threat analysis and propose a security architecture, including specific protocols to protect privacy and ensure robustness. They discuss design decisions, implement security protocols, and conduct a quantitative assessment of the proposed solutions. The paper also explores the integration of on-board computers and positioning devices, highlighting the business opportunities and research challenges. Key security concerns include ensuring the integrity of life-critical information, establishing driver liability, and protecting privacy. The authors propose a system model based on IEEE 802.11-like technology and analyze various attacks, such as bogus information diffusion, cheating with positioning data, and denial of service. They recommend using digital signatures and public key infrastructure (PKI) for message authentication, and discuss key management, including key bootstrapping, rekeying, certification, and revocation. The paper also addresses anonymous public keys to preserve privacy and proposes a key changing algorithm to adapt to vehicle speed and minimize storage costs. Finally, the authors evaluate the performance of different public key cryptosystems and conclude that public key cryptography is suitable for VANETs, with potential for further optimization.This paper addresses the security challenges in vehicular ad hoc networks (VANETs), which are expected to become the most relevant form of mobile ad hoc networks due to the increasing integration of vehicles with communication capabilities. The authors provide a detailed threat analysis and propose a security architecture, including specific protocols to protect privacy and ensure robustness. They discuss design decisions, implement security protocols, and conduct a quantitative assessment of the proposed solutions. The paper also explores the integration of on-board computers and positioning devices, highlighting the business opportunities and research challenges. Key security concerns include ensuring the integrity of life-critical information, establishing driver liability, and protecting privacy. The authors propose a system model based on IEEE 802.11-like technology and analyze various attacks, such as bogus information diffusion, cheating with positioning data, and denial of service. They recommend using digital signatures and public key infrastructure (PKI) for message authentication, and discuss key management, including key bootstrapping, rekeying, certification, and revocation. The paper also addresses anonymous public keys to preserve privacy and proposes a key changing algorithm to adapt to vehicle speed and minimize storage costs. Finally, the authors evaluate the performance of different public key cryptosystems and conclude that public key cryptography is suitable for VANETs, with potential for further optimization.