"I don't understand most of the technical details of Apple's blog post" I do: - Client side vectorization: the photo is processed locally, preparing a non-reversible vector representation before sending (think semantic hash). - Differential privacy: a decent amount of noise is added the the vector before sending it. Enough to make it impossible to reverse lookup the vector. The noise level here is ε = 0.8, which is q…
A good privacy story actually looks like not sending any info to anyone else anywhere at any time.