A Staff-level architecture guide to securing the runtime environment against rooting, hooking frameworks, and emulators. In  Part 1 , we designed the Stateless Blueprint. In  Part 4 , we secured the user’s identity with Passkeys. But there is a silent, systemic risk:  What if the environment itself is compromised? If your app is running on a rooted device with a hooking framework (like Frida or Xposed) or within a sophisticated emulator, even the best encryption and Passkeys can be undermined via memory injection or screen scraping. Today, we bridge the gap between “Who is the user?” and “Is the device trustworthy?” ⚡  TL;DR Compromised environments  allow attackers to bypass local security controls and manipulate runtime logic. Play Integrity API  provides a cryptographically signed verdict on app binary, device integrity, and licensing. Tiered Enforcement:  Align your security requirements with business risk — reserving high-value actions for “...