An embodiment takes the form of an accessory for attachment to a communication device, the accessory comprising a microphone disposed on the accessory to detect sound, a cryptographic module disposed on the accessory in communication with the microphone to generate encrypted audio data based on the detected sound, a communication interface disposed on the accessory in communication with the cryptographic module configured to convey the encrypted audio data to the communication device, and an audio-sensor inhibitor arranged to be positioned adjacent to a communication-device audio sensor.