Mitigating Adversarial Effects Through Randomization

This paper proposed to utilize randomization to mitigate adversarial effects (https://arxiv.org/pdf/1711.01991.pdf). By combining the proposed randomization method with an adversarially trained model, it ranked No.2 among 107 defense teams in the NIPS 2017 adversarial examples defense challenge (https://www.kaggle.com/c/nips-2017-defense-against-adversarial-attack).

The approach

The main ideal of the defense is to utilize randomization to defend adversarial examples:

• Random Resizing: after pre-processing, resize the original image (size of 299 x 299 x 3) to a larger size, Rnd x Rnd x 3, randomly, where Rnd is within the range [310, 331).
• Random Padding: after resizing, pad the resized image to a new image with size 331 x 331 x 3, where the padding size at left, right, upper, bottom are [a, 331-Rnd-a, b, 331-Rnd-b]. The possible padding pattern for the size Rnd is (331-Rnd+1)^2.

In general, the pipeline is shown below:

Pros

1. No additional training/finetuning is required
2. Very little computation introduced
3. Compatiable to different networks and different defending methods (i.e., we use randomization + ensemble adversarial training + Inception-Resnet-v2 in our submission)

Ensemble adversarial training model

• http://download.tensorflow.org/models/ens_adv_inception_resnet_v2_2017_08_18.tar.gz

Team Member

• Cihang Xie (Johns Hopkins University)
• Zhishuai Zhang (Johns Hopkins University)
• Jianyu Wang (Baidu Research)
• Zhou Ren (Snap Inc.)

Leaderboard

Our team name is iyswim, and our rank is No.2.

• https://www.kaggle.com/c/nips-2017-defense-against-adversarial-attack/leaderboard

Citing this work

If you find this work is useful in your research, please consider citing:

@inproceedings{xie2017mitigating,
    title={Mitigating Adversarial Effects Through Randomization},
    author={Xie, Cihang and Wang, Jianyu and Zhang, Zhishuai and Ren, Zhou and Yuille, Alan},
    booktitle={International Conference on Learning Representations},
    year={2018}
}