Covers the full spectrum of iOS security work: keychain storage for credentials and tokens, CryptoKit for encryption and signing, passkey implementation, app attestation, file protection levels, and code signing for distribution. The decision tree is genuinely helpful for knowing whether your signing error belongs in keychain diagnostics or the build tooling. Good conflict resolution with related skills like networking (TLS vs payload signing) and data persistence (when to use keychain vs SwiftData). The reference docs include actual SecItem signatures and error codes, not just conceptual overviews. If you're doing anything with secrets, certificates, or cryptography on Apple platforms, this covers the modern API surface without the CommonCrypto baggage.
npx skills add https://github.com/charleswiltgen/axiom --skill axiom-security