Practical and Secure IoT Device Authentication Using Physical Unclonable Functions

Devices in the internet of things (IoT) are frequently (i) resource-constrained, and (ii) deployed in unmonitored, physically unsecured environments. Securing these devices requires tractable cryptographic protocols, as well as cost effective tamper resistance solutions. We propose and evaluate cryptographic protocols that leverage physical unclonable functions (PUFs): circuits whose input to output mapping depends on the unique characteristics of the physical hardware on which it is executed. PUF-based protocols have the benefit of minimizing private key exposure, as well as providing cost-effective tamper resistance. We present and experimentally evaluate an elliptic curve based variant of a theoretical PUF-based authentication protocol proposed previously in the literature. Our work improves over an existing proof-of-concept implementation, which relied on the discrete logarithm problem as proposed in the original work. In contrast, our construction uses elliptic curve cryptography, which substantially reduces the computational and storage burden on the device. We describe PUF-based algorithms for device enrollment, authentication, decryption, and digital signature generation. The performance of each construction is experimentally evaluated on a resource-constrained device to demonstrate tractability in the IoT domain. We demonstrate that our implementation achieves practical performance results, while also providing realistic security. Our work demonstrates that PUF-based protocols may be practically and securely deployed on low-cost resource-constrained IoT devices.