App Attest
Apple's mechanism for establishing and using a server-verified cryptographic key associated with an app instance. It does not replace account authorization.
Technical reference / 22 definitions
The engineering glossary.
Short explanations with primary references and links to working examples. Each definition focuses on what the term actually guarantees—and what it does not.
22 terms
Authentication
Establishing and verifying the identity or session claims of a principal; successful login does not grant every resource permission.
Authorization
The decision whether a principal may perform a particular operation on a particular resource. Distinct from establishing identity.
Broken object-level authorization
An API flaw where an authenticated caller accesses another principal's object without a resource-level permission check.
Cooperative cancellation
A signal a task observes and handles at explicit checks or suspension points. It is not guaranteed preemption or transaction rollback.
Correlation ID
A traceable request identifier used to link logs and operations. It should not itself reveal sensitive credentials or personal data.
Exponential backoff
A retry strategy in which successive delays grow, usually with a cap. Add jitter and retry budgets to avoid synchronized retry storms.
Idempotency
A property in which repeating a logically identical operation does not cause additional intended effects. API implementations need explicit scopes and semantics.
Keychain
Apple's system storage for credentials and small secrets with configurable accessibility and access-control options.
Nonce
A value intended for one use in a protocol. Unpredictability, freshness and context binding depend on the actual protocol and server policy.
Passkey
A credential built on public-key cryptography and FIDO authentication, typically used with a platform credential provider.
Play Integrity
Google Play API for obtaining application and device integrity verdicts for backend risk decisions. Verify verdict details and request binding server-side.
Refresh token rotation
Replacing a refresh credential after use and invalidating the previous credential according to a server-managed session policy.
Replay attack
Reusing previously valid messages or proofs to trigger a second unintended acceptance. Signatures alone do not prevent replay.
Retry jitter
Random variation in retry timing that reduces synchronization across clients and load spikes at recovering dependencies.
Secure Enclave
Hardware-isolated cryptographic support on supported Apple devices. It is not a general-purpose store for arbitrary application secrets.
Structured concurrency
A concurrency model in which asynchronous child work is owned by a structured lifetime, simplifying cancellation and failure propagation.
Threat model
A structured account of assets, attackers, trust boundaries and potential failure paths used to select security controls.
Time to live (TTL)
A configured validity or retention duration. A short TTL helps limit exposure but cannot by itself prevent replay.
Timeout
A caller-defined limit on waiting for an operation. A timeout does not prove a remote side effect did not happen.
Transactional outbox
A pattern for recording an event alongside a database mutation so an independent worker can reliably deliver side effects after commit.
Trust boundary
A point where data or authority crosses from one security context to another, requiring a deliberate validation or authorization decision.