Mixed-Signal Hardware Security Using MixLock: Demonstration in an Audio Application

In this paper, we demonstrate a recently proposed security technique for mixed-signal circuits in the context of a real application. The security technique, called MixLock, is based on logic locking of the digital section of the mixed-signal circuit and can be used as a countermeasure for reverse engineering and counterfeiting. We demonstrate MixLock in an audio application, where the underlying ΣΔ ADC that digitizes the audio input is locked. We show the effect that locking has on the recorded audio quality based on a metric that counts the resultant glitches per second and by also providing a link where the interested reader can download and listen to output audio samples for locked and unlocked versions of the ΣΔ ADC.