Device Integrity

Implements Apple's device integrity APIs for fraud prevention and app authenticity verification. Covers DCDevice for simple per-device bit flags (like tracking promo redemptions) and the full App Attest flow for cryptographic proof that requests come from genuine, unmodified apps. The guide walks through key generation in the Secure Enclave, attestation with Apple's servers, and assertion signing for ongoing request validation. Use this when you need to protect sensitive endpoints, prevent device abuse, or verify that API calls originate from legitimate app instances. The examples include proper keychain persistence and server integration patterns, though you'll need to implement the server-side JWT signing and Apple API verification yourself.