SCAPI: a scalable attestation protocol to detect software and physical attacks

Interconnected embedded devices are increasingly used in various scenarios, including industrial control, building automation, or emergency communication. As these systems commonly process sensitive information or perform safety critical tasks, they become appealing targets for cyber attacks. A promising technique to remotely verify the safe and secure operation of networked embedded devices is remote attestation. However, existing attestation protocols only protect against software attacks, or show limited scalability and robustness. In this paper, we present the first scalable attestation protocol that detects physical attacks. Based on the assumption that physical attacks require an adversary to capture and disable devices for a noticeable amount of time, our protocol identifies devices with compromised hardware and software. Compared to existing solutions, our protocol reduces communication complexity and runtimes by orders of magnitude, precisely identifies compromised devices, and is robust against failures or network disruptions. We show the security of our protocol and evaluate its scalability and robustness. Our results demonstrate that our protocol is highly efficient in well-connected networks and operates robust in disruptive and very dynamic network topologies.