DeviceCheck and App Attest
DeviceCheck allows servers to set and query two bits of per-device state and to verify that a request is coming from a genuine Apple device. App Attest, exposed through the same service, lets a server cryptographically verify that requests are coming from an authentic, uncompromised instance of an app. The API is JWT-authenticated (ES256) and is used as an anti- fraud / anti-abuse signal alongside iOS apps.