18.9. Summary

The Address Book, Calendar Store, and Keychain provide three systemwide stores of user information. These store, respectively, contact information, events, and secrets. A lot of different categories of application can benefit from integrating with these stores.

Using these stores has several advantages over rolling your own. In the case of the keychain, it is likely to be more secure than anything you create for yourself. All of them benefit from having a set of standard tools for editing and viewing outside of your application. This makes things more convenient and familiar for your users, but also makes life easier for you while you are testing.