Oleg Afonin, ElcomSoft:

Activation Lock, or iCloud Lock, is a feature of Find My iPhone, Apple’s proprietary implementation of a much wider protection system generally referred as Factory Reset Protection (FRP). Factory Reset Protection, or “kill switch”, is regulated in the US via the Smartphone Theft Prevention Act of 2015. The Act requires device manufacturers to feature a so-called “kill switch” allowing legitimate users to remotely wipe and lock devices. The purpose of the kill switch was to discourage smartphone theft by dramatically reducing resale value of stolen devices.

According to Apple, “Activation Lock is a feature that’s designed to prevent anyone else from using your iPhone, iPad, iPod touch, or Apple Watch if it’s ever lost or stolen. Activation Lock is enabled automatically when you turn on Find My iPhone. … Even if you erase your device remotely, Activation Lock can continue to deter anyone from reactivating your device without your permission. All you need to do is keep Find My iPhone turned on, and remember your Apple ID and password.”

Follow the headline link, nice explainer.