How should my Cocoa application store the user's license key? [closed]

Question

After the user enters his / her license key, my application activates itself with that key (online). How do I store this activated state and the license key so that the next time the user opens the app, the app will know that it is already activated?

Answer 1

Apple provides a comprehensive facility for this kind of requirement. What you want is the Keychain API.