Study on achieving speech privacy using masking noise

This study focuses on achieving speech privacy using a meaningless steady masking noise. The most effective index for achieving a satisfactory level of speech privacy was selected, choosing between spectral distance and the articulation index. From a result, spectral distance was selected as the best and most practical index for achieving speech privacy. Next, speech along with a masking noise with a sound pressure level value corresponding to various speech privacy levels were presented to subjects who judged the psychological impression of the particular speech privacy level. Theoretical calculations were in good agreement with the experimental results.