Encryption and Authentication with a Lensless Camera Based on a Programmable Mask

Abstract: Lensless cameras replace traditional optics with thin masks, leading to highly multiplexed measurements akin to encryption. However, static masks in conventional designs leave systems vulnerable to simple attacks. This work explores the use of programmable masks to enhance security by dynamically varying the mask patterns. We perform our experiments with a low-cost system (around 100 USD) based on a liquid crystal display. Experimental results demonstrate that variable masks successfully block a variety of attacks while enabling high-quality recovery for legitimate users. The system's encryption strength exceeds AES-256, achieving effective key lengths over 2'500 bits. Additionally, we demonstrate how a programmable mask enables robust authentication and verification, as each mask pattern leaves a unique fingerprint on the image. When combined with a lensed system, lensless measurements can serve as analog certificates, providing a novel solution for verifying image authenticity and combating deepfakes.