RX-PUF: Low Power, Dense, Reliable, and Resilient Physically Unclonable Functions Based on Analog Passive RRAM Crossbar Arrays

We propose a novel architecture ("RX-PUF") for physically unclonable functions (PUF) based on analog RRAM crossbar array circuits. RX-PUF takes advantage of unique RRAM properties, such as I-V nonlinearity, and its device-to-device (d2d) variations and tunability. As a proof of concept, we have prototyped a 600 kb challenge response pair (CRP) PUF using 250 nm half-pitch (F) 20×20 crossbar arrays with passively integrated devices. The RX-PUF prototype features excellent physical characteristics, e.g. ~1600 F2/bit density and up to 41 fJ/bit energy efficiency. Its functional performance, improved by utilizing hidden input, is also very promising. The measured bit error rate (BER) was 0.7% at RT and ≤ 5.3% at 100°C, even without using any error correction methods. The measured responses showed near-ideal uniformity (50.04%) and inter-HD (50.12%) and passed all relevant NIST randomness tests. The preliminary results showed also very high resilience of RX-PUF against machine learning (ML) attacks.