By connecting sensors, smart devices and everyday physical objects with the Internet, IoT provides a new form of communications for people and devices, which makes the virtual information world integrated seamlessly with the real world. As many of these applications are related to a user’s daily life, privacy and security aspects are very important. Unfortunately, the nature of the complex and heterogenous structure of IoT makes the security issues very challenging. In addition, most nodes are resource-limited, which makes the feature of lightweight necessary for IoT security mechanisms. The Inventors propose a lightweight protocol that satisfies all security requirements, via a novel secret sharing scheme, whereby the secret is used as an authenticator and the shares are used as authenticator tokens.