Revealing Microphone Nonlinear Behavior and Building an Ultrasonic Jammer

Explore a comprehensive conference talk from Hack In The Box Security Conference that delves into innovative counter-surveillance technology through the development of an ultrasonic jammer. Learn about the exploitation of microphone nonlinear behavior using Dynamic Intermodulation Modulation (DIM) algorithm and a sophisticated ultrasonic speaker array design. Discover how this technology effectively disrupts various types of microphones including Electret Condenser Microphones (ECM), Micro-Electro-Mechanical Systems (MEMS), and piezoelectric ceramics. Examine detailed test results demonstrating the jammer's effectiveness against advanced Speech-to-Text (STT) models like iFLYTEK and Otter.ai, with disruption rates approaching 100%. Understand the practical applications of this technology in both large-scale deployments and compact, portable versions suitable for small group interactions, all while maintaining speech indecipherability to both human ears and AI STT models. Presented by Dr. Qing Wang, a cybersecurity researcher and winner of multiple security competitions including Tianfu Cup 2021 and GeekPwn, this 50-minute presentation offers valuable insights into cutting-edge privacy protection measures in our increasingly connected world.