Micpro

What is MicPro?

We aim to achieve voiceprint privacy protection with microphone module. Specifically, we use a modified CELP codec to transform the audio.

Brief Introduction

MicPro is the first privacy-enhanced microphone module that can produce anonymous audio recordings with bio-metric information suppressed while preserving speech quality for human perception or linguistic content for speech recognition. Limited by the hardware capabilities of microphone modules, previous works that modify recording at the software level are inapplicable. To achieve anonymity in this scenario, MicPro transforms formants, which are distinct for each person due to the unique physiological structure of the vocal organs, and formant transformations are done by modifying the linear spectrum frequencies (LSFs) provided by a popular codec (i.e., CELP) in low-latency communications.

To strike a balance between anonymity and usability, we use a multi-objective genetic algorithm (NSGA-II) to optimize the transformation coefficients. We implement MicPro on an off-the-shelf microphone module and evaluate the performance of MicPro on several ASV systems, ASR systems, corpora, and in real-world setup.Our experiments show that for the state-of-the-art ASV systems,MicPro outperforms existing software-based strategies that utilize signal processing (SP) techniques, achieving an EER that is 5∼10% higher and MMR that is 20% higher than existing works while maintaining a comparable level of usability.

How does MicPro work?

Demo

We show how to record and anonymize audio with our MicPro microphone (Respeaker Core V2).

Contact

Wenyuan Xu (wyxu@zju.edu.cn)
Xiaoyu Ji (xji@zju.edu.cn)

Publications

Shilin Xiao, Xiaoyu Ji, Chen Yan, Zhicong Zheng, Wenyuan Xu. "MicPro: Microphone-based Voice Privacy Protection", accepted by ACM Conference on Computer and Communications Security (CCS) 2023.