Cryptoanalysis of Pairing-free Certificateless Aggregate Signcryption Schemes*

certificateless aggregate signcryption offers improved efficiency, scalability, flexibility, and security compared to traditional certificate-based signcryption schemes, which makes that it becomes a preferred solution for ensuring secure communication in various applications.Recently, to solve network congestion, feedback delay and privacy leakage during transmission in internet of vehicles, Xie et al. proposed an efficient certificateless aggregate signcryption with online/offline encryption. They claimed that their scheme is secure against the attacks from Type I and Type II adversaries, and can trace the real identity of a malicious vehicle. However, by analyzing it, we found that their schemes can not satisfy the claimed security. Finally, we give the corresponding attacks and the detailed improved scheme.