Lesson 214

Privacy Technologies

Computing on data you can't see

1:00

How to get answers from data without exposing the people inside it — from re-identification attacks and differential privacy to homomorphic encryption, MPC, zero-knowledge proofs, and federated learning.

By the end, you can

  • Explain why removing names alone does not anonymize a dataset and define quasi-identifier.
  • State the differential privacy guarantee in terms of databases D and D′ and describe what epsilon controls.
  • Describe how the Laplace mechanism adds noise and why accuracy is preserved at the aggregate level.
  • Explain what homomorphic encryption enables, how bootstrapping extends it to unlimited operations, and why the server never learns the plaintext.
  • Describe Yao's millionaires problem and how MPC solves it without a trusted third party.
  • State the three properties of a zero-knowledge proof and explain how zk-SNARKs power zk-rollups.
  • Describe the federated learning architecture, explain the gradient leakage risk, and name mitigations.
  • Articulate the privacy-vs-utility trade-off that runs through all these techniques.
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