Secure Enclave
Encrypted Data Storage
https://support.apple.com/guide/security/how-data-files-are-created-and-protected-sece8608431d/web
Keychain
Access Control
Data Protection Classes
Keybags
https://support.apple.com/guide/security/aside/sec8e00e0dd8/1/web/1
Securityd
Passcode
Used for entropy
Hardware-based Rate-limit enforced by the Secure Enclave
Tangling algorithm PBKDF2. UID is pseudorandom function (PRF)
https://support.apple.com/guide/security/passcodes-sec20230a10d/web