tensorflow_privacy/research/mi_lira_2021

This directory contains code to reproduce our paper:

"Membership Inference Attacks From First Principles" https://arxiv.org/abs/2112.03570 by Nicholas Carlini, Steve Chien, Milad Nasr, Shuang Song, Andreas Terzis, and Florian Tramer.

###INSTALLING

You will need to install fairly standard dependencies

pip install scipy, sklearn, numpy, matplotlib

and also some machine learning framework to train models. We train our models with JAX + ObJAX so you will need to follow build instructions for that https://github.com/google/objax https://objax.readthedocs.io/en/latest/installation_setup.html

###RUNNING THE CODE

####1. Train the models

The first step in our attack is to train shadow models. As a baseline that should give most of the gains in our attack, you should start by training 16 shadow models with the command

bash scripts/train_demo.sh

or if you have multiple GPUs on your machine and want to train these models in parallel, then modify and run

bash scripts/train_demo_multigpu.sh

This will train several CIFAR-10 wide ResNet models to ~91% accuracy each, and will output a bunch of files under the directory exp/cifar10 with structure:

exp/cifar10/
- experiment_N_of_16
-- hparams.json
-- keep.npy
-- ckpt/
--- 0000000100.npz
-- tb/

####2. Perform inference

Once the models are trained, now it's necessary to perform inference and save the output features for each training example for each model in the dataset.

python3 inference.py --logdir=exp/cifar10/

This will add to the experiment directory a new set of files

exp/cifar10/
- experiment_N_of_16
-- logits/
--- 0000000100.npy

where this new file has shape (50000, 10) and stores the model's output features for each example.

####3. Compute membership inference scores

Finally we take the output features and generate our logit-scaled membership inference scores for each example for each model.

python3 score.py exp/cifar10/

And this in turn generates a new directory

exp/cifar10/
- experiment_N_of_16
-- scores/
--- 0000000100.npy

with shape (50000,) storing just our scores.

###PLOTTING THE RESULTS

Finally we can generate pretty pictures, and run the plotting code

python3 plot.py

which should give (something like) the following output

Attack Ours (online)
   AUC 0.6676, Accuracy 0.6077, TPR@0.1%FPR of 0.0169
Attack Ours (online, fixed variance)
   AUC 0.6856, Accuracy 0.6137, TPR@0.1%FPR of 0.0593
Attack Ours (offline)
   AUC 0.5488, Accuracy 0.5500, TPR@0.1%FPR of 0.0130
Attack Ours (offline, fixed variance)
   AUC 0.5549, Accuracy 0.5537, TPR@0.1%FPR of 0.0299
Attack Global threshold
   AUC 0.5921, Accuracy 0.6044, TPR@0.1%FPR of 0.0009

where the global threshold attack is the baseline, and our online, online-with-fixed-variance, offline, and offline-with-fixed-variance attack variants are the four other curves. Note that because we only train a few models, the fixed variance variants perform best.