Reusing LBIST as a Physically Unclonable Function: A Low-Overhead PUF Capturing Circuit Transient Responses

Physical unclonable functions (PUFs) are becoming a crucial solution for addressing hardware security challenges in integrated circuits. However, their widespread adoption is often hindered by the significant overhead of dedicated PUF circuits. This article introduces LBIST-PUF, a novel intrinsic PUF that minimizes overhead by ingeniously reusing the existing logic built-in self-test (LBIST) infrastructure. The design generates unique chip fingerprints through capturing transient responses of the circuit under test (CUT) with a high-frequency configurable clock. To ensure robustness, we incorporate a compensation circuit and a signature correction algorithm, enhancing reliability against environmental variations. Experimental evaluation confirms that the LBIST-PUF achieves near-ideal performance: reliability close to 100%, uniqueness of 50.01%, and a pass rate exceeding 95% on the National Institute of Standards and Technology (NIST) statistical tests. These results underscore the potential of our design as a secure, low-cost authentication solution for Internet of Things (IoT) applications.