A Forward-Secure Symmetric Authenticated Key Exchange Scheme With Privacy Preservation for Internet of Things Applications

With the rapid advancement of Internet of Things (IoT) applications, efficient and secure communication is considered a challenging task. Symmetric authenticated key exchange (AKE) is a promising solution due to its lightweight design. However, existing studies have demonstrated that traditional symmetric AKE schemes are unable to achieve perfect forward secrecy (PFS). Although some improved schemes were proposed based on the evolution of long-term secrets, the analysis indicates that there exists a zero-sum trade-off between PFS and self-synchronization. In addition, privacy preservation remains a critical issue. In response, this paper proposes a novel three-party symmetric AKE scheme. Specifically, the secret evolving mechanism to prevent the reverse inference of crucial secret values is constructed in the scheme. Meanwhile, any reachable session state can be self-transferred to the synchronization state at the end of a complete session. The proposed scheme provides anonymity and pseudonym unlinkability to the required party, while also improving the robustness of conditional identity traceability, avoiding false accusations caused by misdirected requests. The formal analysis, heuristic analysis based on the state transition and secrecy dependency, and performance comparison indicate that the proposed scheme achieves essential properties while maintaining manageable overhead.