Content and key distribution system for digital content representing media streams

摘要

A technique of distributing digital content representing media streams, and keys for unlocking that content, to a user. Content is deliverable to the user separately from licenses to that content. Content is delivered encrypted. Licenses are delivered designating selected presentation devices owned by the user. The presentation devices include a secure portion, relatively resistant to tampering by the user, in which each presentation device maintains a unique presentation device key. The user owns one or more such presentation devices, coupled using a local communication link to a local library, which maintains a copy of the content in an encrypted form. The user can search the library for information generally available about the media stream.