Security for Building Automation with Hardware-Based Node Authentication

Providing reasonable security is a fundamental requirement in building and home automation. The authenticity of devices must be protected to prevent cloned or corrupted devices from joining a private network. State-of-the-art systems already provide secured communication links either by a security layer in the interface protocol stack (e.g. the Security Manager Protocol in Bluetooth Low Energy) or by using the Transport Layer Security (TLS) protocol on top of the interface protocol. These solutions have in common that they only protect the communication links. Thus the system is still vulnerable to active and passive physical attacks that aim to clone the device or to extract the used keys. We show an approach with off-the-shelf security trust anchors that allows securing a device against such attacks. The proposed solution allows product authentication with low-cost ready-to use components which can be easily integrated in an architecture similar to existing proposals. We demonstrate the feasibility of the approach by presenting a prototype implementation and discuss performance and security implications. The results indicate that the proposed architecture provides reasonable security at acceptable costs and can serve as template for many applications in the Internet of Things (IoT) context.