The Industrial Internet of Things (IIoT) is changing our way of life and work. As the number of mobile devices connected to IIoT increases, users will face many security challenges, such as insecure communication environments. The certificateless signature (CLS) scheme can ensure the integrity and validity of data and provide secure identity authentication for the IIoT, and several pairing-free CLS schemes have been proposed in recent years. However, we find they are vulnerable to the signature forgery attack of malicious key generation centers by safety analysis, which does not realize the security they have claimed. To solve this problem, we show an improved CLS scheme that achieves anonymity and formally proves its security under the hardness of the discrete logarithm problem in the random oracle. Comprehensive performance analysis and comparison show that our scheme has less communication and computation costs with higher security, and our construction is suitable for scenarios with limited resources. Finally, we apply this scheme to construct a mutual identity authentication protocol in the healthcare IIoT environment.

In future intelligent transportation systems, vehicular ad hoc network (VANET) is a popular application. They provide early warning of dangers through wireless communication to improve road safety. Therefore, we should protect messages from leakage and changes during transmission. To ensure the security issues in the communication process, we propose a secure and effective certificateless signcryption scheme with multiple messages and multiple receivers and prove its confidentiality and unforgeability based on the hardness of the discrete logarithm problem and the computational Diffie Hellman problem. Our scheme implements the signature and encryption of multiple messages for different receivers and achieves anonymity for the receiver. Based on our signcryption scheme, we design an identity authentication and key agreement protocol applying the construction in VANET. In addition, we also point out that through comprehensive performance analysis, our proposal has higher security and efficiency of computation and communication compared to other signcryption constructions.