Not enough details about DIS (Device Integrity Service)

[cmarco0]

The DIS component needs better definition. It is unclear what the component for smartphones is, how to interact with it, what are its functionality etc...

Clarify that the Strongbox Keymaster serves as the HSM (Hardware Security Module) for Android, providing various functionalities including Key Attestation. Clarify that the Secure Enclave serves as the HSM for iPhone, with DeviceCheck acting as a series of services that provides the ability to verify the authenticity of the phone, its keys, and its apps.