2 A Reconfigurable RRAM Physically Unclonable Function Utilizing Post-Process Randomness Source With −6 Native Bit Error Rate

Physically unclonable functions (PUFs) are promising primitives for hardware security with wide applications in the lnternet of Things (IoT), e.g., authentication and encryption key generation 1, 2. Most silicon PUFs utilize process variability of semiconductor manufacturing 1, 3, 4. These implementations are sensitive to variations in operating conditions (e.g., supply voltage and temperature variations) and undergo significant native bit-error-rates (N-BERs). Thus, additional stabilizing strategies, such as ECC, majority voting, and masking, are necessary. Furthermore, the PUF key after enrollment cannot be changed in prior implementations 1–5. This could be unsafe if the PUFs are repeatedly used in insecure environments, as PUFs suffer from the challenges of ownership change and overuse (Fig. 25.2.1).