STCA: Stacked Token-based Continuous Authentication Protocol for Zero Trust IoT

Network technology developments are blurring the security boundary of the Internet of Things (IoT), making it difficult for traditional border-based security architectures to cope with endless internal attacks. The Zero Trust Architecture (ZTA), with its core concept of “Never Trust, Always Verify”, effectively addresses this problem. Continuous Authentication (CA) is an indispensable component of the zero trust IoT. However, existing CA protocols are impractical to deploy on zero trust IoT due to their dependence on specific properties and thirst for resources. Therefore, this paper proposes a continuous authentication protocol, namely STCA, that uses stacked tokens to ensure the legitimacy of entities during a whole session. Through the theoretical analysis and simulation results, STCA resists several common attacks. The comparison analysis indicates that STCA has a better performance compared with related CA protocols, thereby demonstrating it is more suitable for zero trust IoT.