A Secure Certificateless Signature Scheme for Cloud-Assisted Industrial IoT

Although the cloud-assisted Industrial Internet of Things (IIoT) is emerging as one of the promising technologies to improve personal lifestyles, security and privacy issues are still challenging. Secure certificateless signature (CLS) schemes without certificates for the authentication of public keys are considered suitable for the resource-constrained IIoT security and authentication. Recently, Wang et al. pointed out several security weaknesses on the existing CLS schemes and then constructed a novel efficient CLS scheme based on the blockchain technique and the smart contract. In this work, we show that Wang et al.’s scheme is broken by key recovery attacks: anyone can recover the entire private keys of any users. We then propose a new secure CLS scheme and prove its unforgeability against type I and type II adversaries under the hardness assumption of the Elliptic Curve Diffie-Hellman problem.