Abstract: A system and method that allows client devices with different characteristics and users with different preferences to receive customized content from servers in an open, networked environment, regardless of the server's prior knowledge of the clients' configurations or the users' preferences. The embodiments allow the implementation of a secure, for-pay content delivery system wherein content providers can deliver paid content in an appropriate format over an open, networked environment, such as the Internet, to their subscribers without the fear of copyright violation. In particular, these embodiments prevent an authorized user from transferring to non-authorized users a key or other embodiment of a right that would allow the non-authorized users to access the for-pay content.