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DP-SGD mechanisms

DP-SGD adds calibrated noise to a clipped gradient at every step. Privacy is composed step-by-step: each call to the noise mechanism is a separate DpProcess, multiplied by the number of training steps in the accountant.

Mechanisms

  • Gaussian — independent Gaussian noise on the clipped gradient; the canonical DP-SGD release.

Pairing with sampling

DP-SGD typically pairs the Gaussian mechanism with Poisson subsampling (opake.dpsgd.sampling.PoissonSampler). The accounting form is opake.dpsgd.accounting.poisson(opake.dpsgd.accounting.gaussian(nm), sample_rate=q); multiply by * num_steps for full-training privacy.

See also