In-Situ Privacy via Mixed-Signal Perturbation and Hardware-Secure Data Reversibility

The swift proliferation of edge intelligence and ubiquitous data generation have heightened privacy into a pressing societal need. State-of-the-art reversible privacy protection requires significant hardware resources at the edge with distinct architecture for sensors and security, leading to a rise in hardware overhead and expanded attack surfaces. To address these challenges, we propose a time-domain mixed-signal (TD-MS) circuit architecture facilitating in-situ privacy (ISP) with hardware-secured data reversibility. The proposed TD-MS ISP unites data acquisition, data conversion, key generation, and protection while providing authorized device-specific unclonable data recovery for forensic purposes. At the system level, we demonstrate the attack resilience and privacy-preserving computation performance by implementing a custom embedded system applied to real-world surveillance scenarios. At the circuit level, we showcase custom TD-MS circuits, evaluating their energy and area efficiency against a digital baseline implemented in 65nm technology. With full-stack SPICE simulations for both the baseline digital and proposed TD-MS circuits, we measured a $670\times$ energy/frame savings against the embedded system, $3\times$ area reduction and $3.2\times$ energy TD-MS gains over digital.