Entangled Watermarks as a Defense against Model Extraction

This repository is an implementation of the paper Entangled Watermarks as a Defense against Model Extraction, published in 30th USENIX Security Symposium. In this repository, we show how to train a watermarked DNN model that is robust against model extraction. The high-level idea is that a special watermark is designed such that it could be used to verify the owenrship of the model if it is stolen by model extraction. For more details, please read the paper.

We test our code on five datasets: MNIST, Fashion-MNIST, Google Speech Commands (10-classes), CIFAR-10, and CIFAR-100.

Dependency

Our code is implemented and tested on Tensorflow. Following packages are used by the training code.

tensorflow==1.14.0

Preprocessing code for Google Speech Commands is modifed based on this github repository. The required packages include:

keras==2.2.5
kapre==0.1.3.1
librosa==0.6
tqdm

To run the codes on CIFAR-10 or CIFAR-100, tensorflow_datasets is required.

SVHN is used as out-of-distribution (OOD) watermark (optional, definition can be found in the paper) for CIFAR-10 and CIFAR-100, scipy is needed to load SVHN.

Preprocessing and Training

MNIST and Fashion-MNIST need to be downloaded (4 .gz files as provided on the corresponding website) into the data folder. Then use the following line to conver them to .pkl file.

python prepare_mnist.py --dataset {mnist/fashion}

Note that to use OOD watermark for MNIST or Fashion MNIST, both datasets need to be saved as .pkl files in the data folder.

For Google Speech Command dataset, downloading is included in the preprocssing script:

python prepare_speechcmd.py

To use OOD watermark, add the flag --OOD [one to nine] to the line above.

For CIFAR datasets, no preprocessing script is needed. But to use OOD watermark, train_32x32.mat from SVHN needs to be downloaded to the data folder.

After preprocessing, a watermarked DNN model could be trained by the following line.

python train.py --dataset [mnist/fashion/speechcmd/cifar10/cifar100] --default 1

There are a number of arguments that could be used to set the hyperparameters. The interpretation and configuration of these hyperparameters are explained in our paper. Note that by setting the flag --default 1, pre-defined hyperparameters will be used. The train.py script also contains a model extraction attack to test the robustness of the watermarks. It is only for testing purpose and is not necessary for training the model.

Questions or suggestions

If you have any questions or suggestions, feel free to send me an email at [email protected]