Permissionable Attributes allows you to declare which attributes of a model have permissions associated with them and what those permissions are.

The best example of where you would use this plugin is for a community site where you have certain attributes on a user model that are only viewable to certain people. For example, some attributes might be viewable to the entire public, while others might only be available to that user's friends. The plugin only supports mutually exclusive permissions. Meaning, an attribute is either just viewable by the public or just viewable by friends but not both. However, if an attribute is viewable by the public your helpers should probably be smart enough to that friends should also be able to view them. See the README for more info:

http://permissionable-attributes.googlecode.com/svn/trunk/README