Privacy-Preserving Authentication Protocols for IoT Devices Using the SiRF PUF

Authentication between IoT devices is important for maintaining security, trust and data integrity in an edge device ecosystem. The low-power, reduced computing capacity of the IoT device makes public-private, certificate-based forms of authentication impractical, while other lighter-weight, symmetric cryptography-based approaches, such as message authentication codes, are easy to spoof in unsupervised environments where adversaries have direct physical access to the device. Such environments are better served by security primitives rooted in the hardware with capabilities exceeding those available in cryptography-only frameworks. A key foundational hardware security primitive is the physical unclonable function or PUF. PUFs are well known for removing the need to store secrets in secure non-volatile memories, and for providing very large sets of authentication credentials. In this article, we describe two PUF-based mutual authentication protocols rooted in the entropy provided by a strong PUF. The security properties of the authentication protocols, called COBRA and PARCE, are evaluated in hardware experiments on SoC-based FPGAs, and under extended industrial-standard operating conditions. A codesign-based system architecture is presented in which the SiRF PUF and core authentication functions are implemented in the programmable logic as a secure enclave, while network and database operations are implemented in software on an embedded microprocessor.