Long Li

The smart environment is a crucial application of the Internet of Things (IoT). Due to its growing security and efficiency needs, recent years have seen the proposal of numerous authentication and key agreement (AKA) protocols. Unfortunately, most of existing AKA protocols only support one-to-one AKA and rely on the elliptic curve cryptosystem, resulting in huge overhead. In addition, these protocols fail to consider the resource-asymmetric characteristics of this scenario. That is, the resources on the gateway (GW) side are abundant, while the resources on user sides and device sides are limited. In order to achieve efficient and secure one-to-many AKA establishment in this scenario, where one-to-many means that users can realize key agreements with multiple smart devices (SDs) at the same time. For the first time, this article uses the one-to-many computing structure of the Chinese remainder theorem (CRT) to design an efficient one-to-many AKA establishment, which is perfectly adapted to resource-asymmetric allocation in smart environments. Compared with existing solutions, this solution has the following advantages. First, our protocol is suitable for resource-asymmetric environments, where the GW acts as an intermediate node and uses rich resources to integrate multiple AKA requests. Second, the solution supports users to negotiate session keys with multiple SDs at the same time. Third, we prove the protocol’s security under the real-or-random (ROR) model. In addition, we perform formal security verification of the protocol using the automated validation of Internet security protocols and applications (AVISPAs) tool. Finally, the security and efficiency of this solution are superior to similar solutions. Specifically, our solution can meet 18 security and functionality requirements. Compared with the latest similar scheme, assuming that the number of SDs is ten, our scheme reduces the computational cost by 75.75%. At the same time, in terms of communication cost, our protocol reduces it by 37.78%.

The vehicular ad hoc network (VANET) is a basic component of intelligent transportation systems. Due to the growing security and privacy-preserving requirements of the VANET, a lot of conditional privacy-preserving authentication (CPPA) protocols have been proposed in recent years. Unfortunately, the traditional CPPA protocols, which are based on a trusted authority (TA) and rely solely on classical mathematical problems, cannot resist quantum attacks. Moreover, these protocols do not take into account the increasingly complex traffic flow in the VANET and cannot utilize fog nodes (FNs) to assist in the TA’s authentication work. In this paper, we design a lattice-based and fog-assisted conditional privacy-preserving authentication (LFCPPA) protocol to solve the above challenges. Compared to existing solutions, we have made the following improvements. First, our protocol is resistant to quantum attacks. Second, the solution supports batch processing of signature verification and mutual authentication of identity between the TA / FNs and vehicles. Third, in our design, FNs reduce the computing pressure of the TA to improve the efficiency of the system. In addition, we demonstrate the security of the protocol under the random oracle model with provable security. Finally, the efficiency and security of this scheme are better than similar solutions. Specifically, compared with the latest scheme, in terms of computational cost, our scheme is reduced by 74.47%, 85.58%, 19.69%, and 85.90% in the four stages of the protocol. Meanwhile, in terms of communication cost, our protocol reduces it by 89.98%.