Link to this headingKeychain
Link to this headingSSH Keys
https://gist.github.com/arianvp/5f59f1783e3eaf1a2d4cd8e952bb4acf
Link to this headingPasskey
Passkeys use iCloud Keychain public key credentials, eliminating the need for passwords. Instead, they rely on biometric identification, such as Touch ID and Face ID in iOS, or a specific confirmation in macOS for generating and authenticating accounts.
As the authenticator, your Apple device generates a unique public-private key pair for every account it creates on a service. The authenticator retains the private key and shares its public key with the server, known as the relying party.