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.
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.
| Verdict | Official | Local | Agreement |
|---|---|---|---|
| Total evaluated | 147 | 147 | — |
| UNSAT (certified safe) | 103 | 103 | 100% |
| SAT (counterexample) | 35 | 34 | 97.1% |
| Timeout | 9 | 0 | — |
| Unknown | 0 | 10 | — |
| Overall verdict match | — | — | 137 / 147 (93.2%) |