CorruptEncoder: Data Poisoning based Backdoor Attacks to Contrastive Learning

Fuente: arXiv
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Main Authors: Zhang, Jinghuai, Liu, Hongbin, Jia, Jinyuan, Gong, Neil Zhenqiang
Format: Preprint
Published: 2022
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author Zhang, Jinghuai
Liu, Hongbin
Jia, Jinyuan
Gong, Neil Zhenqiang
author_facet Zhang, Jinghuai
Liu, Hongbin
Jia, Jinyuan
Gong, Neil Zhenqiang
contents Contrastive learning (CL) pre-trains general-purpose encoders using an unlabeled pre-training dataset, which consists of images or image-text pairs. CL is vulnerable to data poisoning based backdoor attacks (DPBAs), in which an attacker injects poisoned inputs into the pre-training dataset so the encoder is backdoored. However, existing DPBAs achieve limited effectiveness. In this work, we take the first step to analyze the limitations of existing backdoor attacks and propose new DPBAs called CorruptEncoder to CL. CorruptEncoder introduces a new attack strategy to create poisoned inputs and uses a theory-guided method to maximize attack effectiveness. Our experiments show that CorruptEncoder substantially outperforms existing DPBAs. In particular, CorruptEncoder is the first DPBA that achieves more than 90% attack success rates with only a few (3) reference images and a small poisoning ratio 0.5%. Moreover, we also propose a defense, called localized cropping, to defend against DPBAs. Our results show that our defense can reduce the effectiveness of DPBAs, but it sacrifices the utility of the encoder, highlighting the need for new defenses.
format Preprint
id arxiv_https___arxiv_org_abs_2211_08229
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle CorruptEncoder: Data Poisoning based Backdoor Attacks to Contrastive Learning
Zhang, Jinghuai
Liu, Hongbin
Jia, Jinyuan
Gong, Neil Zhenqiang
Cryptography and Security
Computer Vision and Pattern Recognition
Machine Learning
Contrastive learning (CL) pre-trains general-purpose encoders using an unlabeled pre-training dataset, which consists of images or image-text pairs. CL is vulnerable to data poisoning based backdoor attacks (DPBAs), in which an attacker injects poisoned inputs into the pre-training dataset so the encoder is backdoored. However, existing DPBAs achieve limited effectiveness. In this work, we take the first step to analyze the limitations of existing backdoor attacks and propose new DPBAs called CorruptEncoder to CL. CorruptEncoder introduces a new attack strategy to create poisoned inputs and uses a theory-guided method to maximize attack effectiveness. Our experiments show that CorruptEncoder substantially outperforms existing DPBAs. In particular, CorruptEncoder is the first DPBA that achieves more than 90% attack success rates with only a few (3) reference images and a small poisoning ratio 0.5%. Moreover, we also propose a defense, called localized cropping, to defend against DPBAs. Our results show that our defense can reduce the effectiveness of DPBAs, but it sacrifices the utility of the encoder, highlighting the need for new defenses.
title CorruptEncoder: Data Poisoning based Backdoor Attacks to Contrastive Learning
topic Cryptography and Security
Computer Vision and Pattern Recognition
Machine Learning
url https://arxiv.org/abs/2211.08229