Struggle with Adversarial Defense? Try Diffusion

Fuente: arXiv
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Main Authors: Li, Yujie, Wang, Yanbin, Xu, Haitao, Liu, Bin, Sun, Jianguo, Guo, Zhenhao, Ma, Wenrui
Format: Preprint
Published: 2024
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author Li, Yujie
Wang, Yanbin
Xu, Haitao
Liu, Bin
Sun, Jianguo
Guo, Zhenhao
Ma, Wenrui
author_facet Li, Yujie
Wang, Yanbin
Xu, Haitao
Liu, Bin
Sun, Jianguo
Guo, Zhenhao
Ma, Wenrui
contents Adversarial attacks induce misclassification by introducing subtle perturbations. Recently, diffusion models are applied to the image classifiers to improve adversarial robustness through adversarial training or by purifying adversarial noise. However, diffusion-based adversarial training often encounters convergence challenges and high computational expenses. Additionally, diffusion-based purification inevitably causes data shift and is deemed susceptible to stronger adaptive attacks. To tackle these issues, we propose the Truth Maximization Diffusion Classifier (TMDC), a generative Bayesian classifier that builds upon pre-trained diffusion models and the Bayesian theorem. Unlike data-driven classifiers, TMDC, guided by Bayesian principles, utilizes the conditional likelihood from diffusion models to determine the class probabilities of input images, thereby insulating against the influences of data shift and the limitations of adversarial training. Moreover, to enhance TMDC's resilience against more potent adversarial attacks, we propose an optimization strategy for diffusion classifiers. This strategy involves post-training the diffusion model on perturbed datasets with ground-truth labels as conditions, guiding the diffusion model to learn the data distribution and maximizing the likelihood under the ground-truth labels. The proposed method achieves state-of-the-art performance on the CIFAR10 dataset against heavy white-box attacks and strong adaptive attacks. Specifically, TMDC achieves robust accuracies of 82.81% against $l_{\infty}$ norm-bounded perturbations and 86.05% against $l_{2}$ norm-bounded perturbations, respectively, with $ε=0.05$.
format Preprint
id arxiv_https___arxiv_org_abs_2404_08273
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Struggle with Adversarial Defense? Try Diffusion
Li, Yujie
Wang, Yanbin
Xu, Haitao
Liu, Bin
Sun, Jianguo
Guo, Zhenhao
Ma, Wenrui
Computer Vision and Pattern Recognition
Cryptography and Security
Adversarial attacks induce misclassification by introducing subtle perturbations. Recently, diffusion models are applied to the image classifiers to improve adversarial robustness through adversarial training or by purifying adversarial noise. However, diffusion-based adversarial training often encounters convergence challenges and high computational expenses. Additionally, diffusion-based purification inevitably causes data shift and is deemed susceptible to stronger adaptive attacks. To tackle these issues, we propose the Truth Maximization Diffusion Classifier (TMDC), a generative Bayesian classifier that builds upon pre-trained diffusion models and the Bayesian theorem. Unlike data-driven classifiers, TMDC, guided by Bayesian principles, utilizes the conditional likelihood from diffusion models to determine the class probabilities of input images, thereby insulating against the influences of data shift and the limitations of adversarial training. Moreover, to enhance TMDC's resilience against more potent adversarial attacks, we propose an optimization strategy for diffusion classifiers. This strategy involves post-training the diffusion model on perturbed datasets with ground-truth labels as conditions, guiding the diffusion model to learn the data distribution and maximizing the likelihood under the ground-truth labels. The proposed method achieves state-of-the-art performance on the CIFAR10 dataset against heavy white-box attacks and strong adaptive attacks. Specifically, TMDC achieves robust accuracies of 82.81% against $l_{\infty}$ norm-bounded perturbations and 86.05% against $l_{2}$ norm-bounded perturbations, respectively, with $ε=0.05$.
title Struggle with Adversarial Defense? Try Diffusion
topic Computer Vision and Pattern Recognition
Cryptography and Security
url https://arxiv.org/abs/2404.08273