reconstruction-attacks

Code for hands-on experience with reconstruction attacks in a simple setting with a server that answers linear queries on hidden, pseudorandom datasets in {-1,+1}^n. There is some structure in the random datasets to make the reconstruction more interesting: The fraction of coordinates with value +1 is around 2/3. Once the server is up (see below) the reconstruction attack code can use it to answer linear queries on datasets, identified with a "challenge ID" string. A baseline implementation is included as a template. The server keeps track of queries and provides a leaderboard of submissions on n-dimensional datasets using at most 2n queries. Everything is meant to be used in a small-scale setting, like teaching a class on differential privacy, and will not scale to large sets of users.

Run locally

Create a virtual environment and install the dependencies:

python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt

Start the production server on http://127.0.0.1:8000:

gunicorn --bind 127.0.0.1:8000 --workers 1 --threads 4 linear_query_server:app

Set SERVER_URL = "http://127.0.0.1:8000" in the notebook. The health check is available at http://127.0.0.1:8000/health and the leaderboard at http://127.0.0.1:8000/leaderboard/?n=100.

Run the local tests with:

python3 -m unittest discover -s tests

Deployment

The seed and leaderboard log are stored in DATA_DIR, which defaults to the local data/ directory. In Railway or Render, set DATA_DIR=/data and attach a persistent volume or disk at /data. Keep the service at one process while it uses the file-based leaderboard. The included Procfile starts Gunicorn with one process and four threads.

Railway

1. Deploy this directory with railway up or connect the GitHub repository in the Railway dashboard.
2. Attach a volume to the web service with mount path /data. The server automatically uses Railway's RAILWAY_VOLUME_MOUNT_PATH variable.
3. In the service settings, set the health-check path to /health.
4. Under Networking, generate a public domain.

Keep the service at one replica because the leaderboard is stored on the attached volume.