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Label-Only Membership Inference

Reproducing a 2021 ML-security paper and everything I learned along the way.

3/6 parts, in reading order. · code on GitHub

  1. Part 1
    What is a membership inference attack?

    The first in a series cataloguing my journey reproducing papers I want to properly understand. Starting with the core idea and vocabulary of membership inference attacks.

  2. Part 2
    The gap attack, and some ML fundamentals

    To build the gap attack I first had to learn how to train a neural network, so this post is mostly the ML setup (CNNs, tensors, loss, gradient descent), with the working attack at the end.

  3. Part 3
    Recovering confidence from labels alone

    Part 2 got us a baseline. Now we ask the model about wobbled copies of a point, and use how reliably it still gets them right as a stand-in for confidence. It beats the baseline, though the obvious way of counting the answers does worse than not augmenting at all.