PolicyKit-kde is a implementation of PolicyKit tool to the look and feel of KDE.
PolicyKit allows easy and secure password management, it can be used by applications to ask their users for a password. Each application defines a set of actions that can be executed by their program. The application will call PolicyKit to see if the user can perform a given action, if not, the application can issue the auth dialog where the user can enter his/her password, root password, the password of a given group of users or even swipe the finger.
PolicyKit-kde consists of two applications: The Authorization agent that receives requests for authentication, and shows a dialog asking for a password. The Authorization manager that is used to manage the authorizations, it is mainly used by system administrators that may want to change the default behavior of a program policies.
For Qt/KDE developers there is Qt library to allow easy integration with you application and PolicyKit.
For more information of how PolicyKit works, it's design and API visit PolicyKit Library Reference Manual