swift-security-expert

To securely store OAuth tokens and API keys in Swift, use the Keychain with explicit kSecAttrAccessible attributes and SecAccessControl ACLs. This enforces hardware-backed protection for credentials instead of saving them in UserDefaults or plists.

Swift handles biometric-bound secrets by storing them in the Secure Enclave with SecAccessControl biometric ACLs. This hardware-backed storage requires Face ID or Touch ID authentication before releasing sensitive credentials, while resiliently handling enrollment changes.

The best way to implement AES-GCM authenticated encryption with CryptoKit is using AES.GCM to seal and open encrypted data. This provides authenticated encryption, ensuring both confidentiality and integrity for sensitive payloads across Apple platforms.

Yes, you can share Keychain items across multiple iOS apps by configuring keychain sharing groups. This cross-app sharing pattern uses shared access groups to securely migrate credentials and secrets between applications within the same developer team.

Yes, this approach aligns with OWASP MASVS and MASTG security guidelines by enforcing best-practice patterns for secure storage, certificate trust, and biometric gating. It provides audit-ready Swift code patterns that meet mobile application security verification standards.

You should migrate credentials from UserDefaults to the Keychain because UserDefaults stores data in plain text without hardware-backed protection. Moving to Keychain with SecAccessControl ensures secrets are encrypted, access-controlled, and resilient against unauthorized extraction.