Forensic Accountability in Heterogeneous Federated Learning
Research Problem
Federated learning can protect raw data locality while still remaining vulnerable to malicious client behavior. Existing Byzantine-robust aggregation methods primarily focus on suppressing or rejecting suspicious updates, but they do not inherently answer two forensic questions: which client was responsible for malicious behavior, and when did that behavior begin?
Why It Matters
In security-sensitive distributed learning systems, mitigation alone is not sufficient. Incident response, accountability, post-hoc investigation, and recovery require longitudinal evidence that can trace anomalous behavior back to a specific participant and localize the onset of an attack without confusing legitimate non-IID client variation with malicious activity.
Technical Focus
- Longitudinal client-update forensics
- Malicious-client attribution
- Attack-onset localization
- Non-IID-aware anomaly calibration
- Magnitude and temporal-residual evidence
- Persistent evidence accumulation
- Robust aggregation versus forensic accountability