Federated Learning — Training Without Centralizing the Data
The most direct way to protect data is to never move it. Federated learning trains a shared model across many devices or organizations without their data ever leaving home — the model travels to the data, learns locally, and only the lessons (not the data) come back. It's how your phone's keyboard improves without uploading what you type, and how hospitals can build a shared model without sharing patient records. This post is about learning from data you're never allowed to see.
The most direct way to protect data is to never move it. Federated learning trains where the data lives (phones, hospitals) and shares only model updates — data minimization by architecture. But updates leak too, so it's combined with differential privacy and secure aggregation; it changes the threat model, not the threat.