Matthew Green – Cryptography Engineering Blog: [June 5, 2019] Apple announced a cool new feature called “Find My”. Unlike Apple’s “Find my iPhone“, which uses cellular communication and the lost device’s own GPS to identify the location of a missing phone, “Find My” also lets you find devices that don’t have cellular support or internal GPS — things like laptops, or (and Apple has hinted at this only broadly) even “dumb” location tags that you can attach to your non-electronic physical belongings.

The idea of the new system is to turn Apple’s existing network of iPhones into a massive crowdsourced location tracking system. Every active iPhone will continuously monitor for BLE beacon messages that might be coming from a lost device. When it picks up one of these signals, the participating phone tags the data with its own current GPS location; then it sends the whole package up to Apple’s servers….(It’s worth mentioning that Apple didn’t invent this idea. In fact, companies like Tile have been doing this for quite a while. And yes, they should probably be worried.) If you haven’t already been inspired by the description above, let me phrase the question you ought to be asking: how is this system going to avoid being a massive privacy nightmare? Let me count the concerns…”