A Lightweight and Secure Certificateless Encryption Scheme for Smart City IoT Security

Abstract The rapid deployment of Internet of Things (IoT) in smart cities urgently demands lightweight encryption schemes to address critical security vulnerabilities in resource-constrained environments. Traditional certificateless encryption schemes suffer from public key replacement attacks and risks of partial key leakage caused by compromised private key generators. To overcome these challenges, this paper proposes a lightweight and secure certificateless encryption scheme. The proposed scheme integrates a Schnorr signature mechanism incorporating user identifiers, secret values, and public keys. Under the standard model, the scheme demonstrates resistance against adaptive chosen ciphertext attacks (CCA2) from both Type I adversaries (capable of replacing public keys) and Type II adversaries (possessing the system master key). Performance evaluation results indicate that the scheme maintains high security while achieving efficient encryption performance and reliable public key verification, making it particularly suitable for secure communication in IoT devices within smart city applications.