README.md

An Embarrassingly Simple Backdoor Attack on Self-supervised Learning

This is the code implementation (pytorch) for our paper:
An Embarrassingly Simple Backdoor Attack on Self-supervised Learning

We design and evaluate CTRL, an extremely simple self-supervised trojan attack. By polluting a tiny fraction of training data (≤ 1%) with indistinguishable poisoning samples, CTRL causes any trigger-embedded input to be misclassified to the adversary’s desired class with a high probability (≥ 99%) at inference. More importantly, through the lens of CTRL, we study the mechanisms underlying self-supervised trojan attacks. With both empirical and analytical evidence, we reveal that the representation invariance property of SSL, which benefits adversarial robustness, may also be the very reason making SSL highly vulnerable to trojan attacks.

Screenshot

Quick Start

1. Train a clean model:
   e.g. SimCLR with ResNet18 on CIFAR10

   python main_train.py --dataset cifar10 --mode normal --method simclr --threat_model our --channel 1 2 --trigger_position 15 31 --poison_ratio 0.01 --lr 0.06 --wd 0.0005 --magnitude 100.0 --poisoning --epochs 800 --gpu 0 --window_size 32 --trial clean

2. Test backdoor attack:
   e.g. SimCLR with ResNet18 on CIFAR10

   python main_train.py --dataset cifar10 --mode frequency --method simclr --threat_model our --channel 1 2 --trigger_position 15 31 --poison_ratio 0.01 --lr 0.06 --wd 0.0005 --magnitude 100.0 --poisoning --epochs 800 --gpu 0 --window_size 32 --trial test 

Todo List

1. SimSiam
2. Defense
3. Linear Evaluation
4. Test and find bugs

License

This code has a GPL-style license.

Cite our paper

@InProceedings{Li_2023_ICCV,
    author    = {Li, Changjiang and Pang, Ren and Xi, Zhaohan and Du, Tianyu and Ji, Shouling and Yao, Yuan and Wang, Ting},
    title     = {An Embarrassingly Simple Backdoor Attack on Self-supervised Learning},
    booktitle = {Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV)},
    month     = {October},
    year      = {2023},
    pages     = {4367-4378}
}

@inproceedings{li2024on,
  title={On the Difficulty of Defending Contrastive Learning against Backdoor Attacks},
  author={Li, Changjiang and Pang, Ren  and Cao, Bochuan Xi, Zhaohan and  Chen, Jinghui and Ji, Shouling and Wang, Ting},
  booktitle={The 33nd USENIX Security Symposium (Security '24)},
  year={2024},
}