The clever cryptography behind Apple’s “Find My” feature

Matthew Green, Johns Hopkins University

In a background phone call with WIRED following its keynote, Apple broke down that privacy element, explaining how its “encrypted and anonymous” system avoids leaking your location data willy nilly, even as your devices broadcast a Bluetooth signal explicitly designed to let you track your device. The stranger’s iPhone then uploads two things to Apple’s server: The encrypted location, and a hash of the laptop’s public key, which will serve as an identifier. But Johns Hopkins’ Green points out that the iPad could upload a series of hashes of all its previous public keys, so that Apple could sort through them to pull out the previous location where the laptop was spotted.

Source: www.wired.com