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Trustworthy AI2026

α,β-CROWN Reproducibility Study

Certified robustness on VNN-COMP CIFAR2020 — research internship at CRNS

An independent reproduction of α,β-CROWN on the VNN-COMP CIFAR2020 benchmark: 147 robustness properties verified locally, with 93.2% agreement with the official verdicts.

93.2%verdict agreement137 / 147 properties · CIFAR2020Verified safe (UNSAT, matched official): 103 of 147Counterexample (SAT, matched official): 34 of 147No verdict (unknown in the local run): 10 of 147Verified safe103Counterexample34No verdict10

Overview

Formal verification only matters if its results can be trusted — and reproduced. During my research internship at the Digital Research Center of Sfax (CRNS), I evaluated α,β-CROWN, a multi-year VNN-COMP winner, by re-running the CIFAR2020 benchmark in an independent environment.

The benchmark asks whether ResNet-style CNNs trained on CIFAR-10 stay robust under L∞ perturbations of ε = 2/255 and 8/255: 147 properties, each pairing an ONNX model with a VNN-LIB specification, under a 300-second timeout.

I built the tooling around the runs: a parser that turns raw verifier logs into structured CSVs, scripts that extract the official per-benchmark results, and a notebook that compares verdicts with confusion matrices and solved-over-time curves.

The study confirmed that α,β-CROWN reproduces well. All 103 certified-safe (UNSAT) verdicts matched, 34 of 35 counterexamples (SAT) matched, and the remaining divergences clustered on the slowest instances near the timeout.

VNN-COMP CIFAR2020: official vs. local α,β-CROWN verdicts (147 properties, 300 s timeout)
VerdictOfficialLocalAgreement
Total evaluated147147—
UNSAT (certified safe)103103100%
SAT (counterexample)353497.1%
Timeout90—
Unknown010—
Overall verdict match——137 / 147 (93.2%)