Dome-Shaped Ultrasonic Jammer for speech privacy protection

Abstract

Smart devices using voice recognition systems such as Google Assistant, Siri, and Alexa have rapidly become popular in recent years. Although these devices are convenient because they can be operated using voice, there is reported to be a risk of their unauthorized operation by sending stealth voice commands from a remote location. In addition, there is the risk of private conversations being eavesdropped on, as conversations can now be recorded and possibly sent wirelessly using extremely small devices. Ultrasonic jammers are a countermeasure to these situations. Ultrasonic jammers use ultrasonic waves to jam the recorder in such a way that the jamming is imperceptible to surrounding humans but adds significant noise to only recorded samples. We developed a prototype dome-shaped ultrasonic jammer, which can spread the jamming signal to a wide surrounding area, and evaluated its initial performance. The performance evaluation results confirmed that the dome-shaped ultrasonic jammer can effectively jam a wider area than a conventional flat parametric speaker conventionally used for jamming.