Dynamic Watermark Generation for Digital Images using Perimeter Gated SPAD Imager PUFs

Abstract

Digital image watermarks as a security feature can be derived from the imager's physically unclonable functions (PUFs) by utilizing the manufacturing variations, i.e., the dark signal non-uniformity (DSNU). While a few demonstrations focused on the CMOS image sensors (CIS) and active pixel sensors (APS), single photon avalanche diode (SPAD) imagers have never been investigated for this purpose. In this work, we have proposed a novel watermarking technique using perimeter gated SPAD (pgSPAD) imagers. We utilized the DSNU of three 64 x 64 pgSPAD imager chips, fabricated in a 0.35 {\mu}m standard CMOS process and analyzed the simulated watermarks for standard test images from publicly available database. Our observation shows that both source identification and tamper detection can be achieved using the proposed source-scene-specific dynamic watermarks with a controllable sensitivity-robustness trade-off.