iPhone, Android Ambient Light Sensors Allow Stealthy Spying

## Executive Summary Researchers at MIT demonstrated a proof-of-concept privacy vulnerability in which ambient light sensors on smart devices—normally permission-free—can be used with computational imaging to recover users' touch gestures and partial color/facial information. The technique relies on low-bitrate light variation inversion; while feasible in lab conditions, captured data rates are very low and no active exploitation is reported. The authors recommend adding permission controls, reducing sensor sampling rates to 1–5 Hz, and lowering quantization to mitigate the risk.