How does DP-SGD work?
hardAnswer
- Standard SGD with two modifications: (1) Clip per-example gradient norm to constant C (bounds sensitivity).
- (2) Add Gaussian noise to sum of clipped gradients before averaging.
- Provides (ε, δ)-differential privacy: presence/absence of any individual has bounded influence on output.
- Tradeoff: more noise → more privacy but worse accuracy.
- Track privacy budget over training epochs (privacy accountant).
- Standard in Google / Apple production ML.
Check yourself — multiple choice
- Random
- Clip per-example gradient norm to C + add Gaussian to gradient sum; provides (ε,δ)-DP: bounded influence per example; track budget over epochs
- Same as dropout
- Not real
DP-SGD: clip + Gaussian noise; (ε,δ)-DP; track privacy budget.
#safety#advanced
Practise MLOps & Data Quality
215 interview questions in this topic.