Machine Learning Security · Inference-Time Defense · Preprint; under review, IEEE Open Journal of the Computer Society

ADS-C: Antidistillation Sampling for Classification

An inference-time defense that changes served probability outputs while provably preserving top-1 predictions. It reduced soft-label distilled-student accuracy in the evaluated image-classification experiments; unchanged labels remain available to hard-label attackers.

Khawaja Abaid Ullah, Mohammad Javad Khojasteh

Method and guarantee

ADS-C modifies the probability distribution returned by a classifier using a per-input confidence-margin budget. The bound preserves the classifier’s top-1 prediction for every input; it does not preserve the probability values or promise calibrated probabilities. The method targets model extraction through soft-label knowledge distillation. An attacker can still query the unchanged hard labels.

A scoped experimental result

In the reported CIFAR-10 experiment at λ = 3, student top-1 accuracy fell from 81.44% ± 0.43 when distilling undefended outputs to 51.80% ± 0.38 with ADS-C outputs: a reduction of 29.64 percentage points (about 29.6). Values are means ± standard deviations over three seeds, as reported in the public implementation. The defended teacher’s top-1 accuracy stayed unchanged. These results apply to the evaluated distillation setup, not all extraction attacks.

See the paper and implementation and reproduction guide for the tested models, other datasets, and full evaluation.

AntidistillBench implements classification defenses under a common model-extraction threat model and a matched-cost evaluation protocol to compare suppression of student learning. Its manuscript is under review. The ADS-C repository linked here is related implementation code; it is not presented as a public release of AntidistillBench.