In wireless network environments, legitimate authentication between communicating parties is a prerequisite for ensuring the security of vehicular network systems. However, traditional centralized authentication protocols generally suffer from single point of failure issues, while most existing distributed authentication schemes face risks of key escrow and identity privacy leakage. Even when pseudonyms are used to conceal users’ real identities, malicious entities can correlate messages sent by the same pseudonymous vehicle to track driving trajectories. To address these challenges, we propose a blockchain-assisted certificateless authentication protocol where vehicle keys are jointly generated by users and a central authority, eliminating key escrow concerns. Furthermore, we design an efficient signcryption algorithm that ensures only legitimate nodes can verify message sources during vehicle authentication, preventing malicious entities from linking broadcasted messages from the same vehicle, thereby achieving unlinkability between messages. Finally, we demonstrate the feasibility of the authentication protocol through security analysis, which also exhibits lower computational and communication overhead.