Diffusion-Based Adversarial Purification for Speaker Verification
Yibo Bai, Xiao-Lei Zhang, Xuelong Li
TL;DR
The paper addresses the vulnerability of automatic speaker verification (ASV) systems to imperceptible adversarial perturbations. It introduces Diffusion-Based Adversarial Purification (DAP), a purification framework that uses a conditional denoising diffusion probabilistic model to reconstruct clean audio before ASV inference. The approach defines a purification operator that preserves the ASV score while removing perturbations, and leverages forward diffusion and a learned reverse denoising process to recover clean speech from adversarial inputs. Experiments on VoxCeleb data show that DAP achieves state-of-the-art purification with minimal distortion to genuine speech, improving defense performance across attack types and ASV backbones.
Abstract
Recently, automatic speaker verification (ASV) based on deep learning is easily contaminated by adversarial attacks, which is a new type of attack that injects imperceptible perturbations to audio signals so as to make ASV produce wrong decisions. This poses a significant threat to the security and reliability of ASV systems. To address this issue, we propose a Diffusion-Based Adversarial Purification (DAP) method that enhances the robustness of ASV systems against such adversarial attacks. Our method leverages a conditional denoising diffusion probabilistic model to effectively purify the adversarial examples and mitigate the impact of perturbations. DAP first introduces controlled noise into adversarial examples, and then performs a reverse denoising process to reconstruct clean audio. Experimental results demonstrate the efficacy of the proposed DAP in enhancing the security of ASV and meanwhile minimizing the distortion of the purified audio signals.
