In September 2010, Google introduced OAuth 1 sign-in controllers to simplify authenticating users from iOS and Mac applications. Starting today, Google offering the Google Toolbox for Mac OAuth 2.0 Controllers. This new library enables Cocoa applications to sign in to Google and other services that conform to the latest draft of the OAuth 2.0 standard.
"From the perspective of both users and developers, the new controllers are similar to the old ones, and are just as easy to use. As before, the controllers handle displaying an embedded web view and interacting with the server, and optionally allow saving the authorization token in the keychain. The server takes care of obtaining the user's password, describing the permissions requested by the application, and asking for captcha responses or 2-step verification or whatever tomorrow's security requires," Google informed.
"The Google Data APIs Library for Objective-C now integrates the OAuth 2.0 controllers, making it the preferred way for developers to let users sign in to the library's many supported APIs."
[Source: Mac Inside Google]