Evaluating the Effectiveness of Protection Jamming Devices in Mitigating Smart Speaker Eavesdropping Attacks Using Gaussian White Noise

Protection Jamming Devices (PJD) are specialized tools designed to sit on top of virtual assistant (VA) smart speakers and hinder them from “hearing” nearby user speech. PJDs aim to protect you from eavesdropping attacks by injecting a jamming signal directly into the microphones of the smart speaker. However, current signal processing routines can be used to reduce noise and enhance speech contained in noisy audio samples. Therefore, we identify a potential vulnerability for speech eavesdropping via smart speaker recordings, even when a PJD is being used. If an attacker can gain access to or facilitate smart speaker recordings they may be able to compromise a user’s speech with successful noise cancellation. Specifically, we are interested in the potential for Gaussian white noise (GWN) to be an effective jamming signal for a PJD. To our knowledge, the effectiveness of white noise and PJDs to protect against eavesdropping attacks has yet to receive a systematic evaluation that includes physical experiments with an actual PJD implementation.