WatchWitch: Interoperability, Privacy, and Autonomy for the Apple Watch

TL;DR

WatchWitch introduces an open Android implementation of the Apple Watch's protocols, enabling interoperability, improved privacy, and user data autonomy, challenging Apple's proprietary ecosystem and enhancing consumer choice.

Contribution

We reverse-engineered Apple's wireless protocols and developed WatchWitch, the first Android-compatible implementation, to improve interoperability and privacy controls for Apple Watch users.

Findings

Successfully reverse-engineered Apple Watch protocols

Enabled Android compatibility with Apple Watch

Enhanced user privacy and data autonomy

Abstract

Smartwatches such as the Apple Watch collect vast amounts of intimate health and fitness data as we wear them. Users have little choice regarding how this data is processed: The Apple Watch can only be used with Apple's iPhones, using their software and their cloud services. We are the first to publicly reverse-engineer the watch's wireless protocols, which led to discovering multiple security issues in Apple's proprietary implementation. With WatchWitch, our custom Android reimplementation, we break out of Apple's walled garden -- demonstrating practical interoperability with enhanced privacy controls and data autonomy. We thus pave the way for more consumer choice in the smartwatch ecosystem, offering users more control over their devices.