A Multi-Protocol, Multi-Channel Architecture for Combining Signal Processing and Physical Unclonable Functions in AlN Surface Acoustic Wave Devices for Post-Quantum Cryptography

Abstract

This work proposes a theoretical architecture that allows a single surface acoustic wave (SAW) device based on aluminum nitride (AlN) to simultaneously perform classical radio-frequency signal processing (filtering, correlation, delay lines) and serve as a physical unclonable function (PUF) for several cryptographic protocols and several radio channels at once. We propose partitioning the device's operating band into N frequency channels, each addressed by its own set of interdigital-transducer (IDT) reflector apodization codes, so that each channel generates an independent challenge–response pair (CRP) space. We build an analytical model of per-channel response entropy that accounts for the scale of AlN-film defects relative to the SAW wavelength, a bit-error-rate (BER) model, a fuzzy-extractor entropy budget, and a mapping from aggregate min-entropy to post-quantum cryptography (PQC) requirements (Kyber/ML-KEM, Dilithium/ML-DSA). We show that, once cross-channel correlation is taken into account, the system's aggregate min-entropy grows sub-linearly with the number of channels (a saturation effect), which sets a practical limit on protocol multiplexing on a single die. The work is theoretical in nature and outlines a program for experimental verification.