Security & Credentials You MUST use this skill for ANY keychain, encryption, passkey, app integrity, file protection, or code signing work. Quick Reference | Symptom / Task | Reference | |----------------|-----------| | Store tokens, passwords, API keys securely | See | | Choose kSecAttrAccessible level, biometric protection | See | | SecItem function signatures, attribute constants | See | | errSecDuplicateItem, errSecItemNotFound, errSecInteractionNotAllowed | See | | Encrypt data, sign payloads, key management | See | | Hash functions, HMAC, AES-GCM, ChaChaPoly, ECDSA, EdDSA, key agreement…