Patent ID: 8255989

Claim:
In a communication network, a method for controlling access by a client to a data stream from a caching server, the method comprising: receiving, from a Key Distribution Centre (KDC), authorization data generated at the KDC, the authorization data including at least one subscription option selected by the client for the data stream; receiving, from a content provider, a session rights object generated by a content provider, the session rights object including at least one purchase option selected by the client for the data stream, and at least one rule that governs access by the client to the data stream, wherein the session rights object cannot be modified by the client; comparing, by the caching server, the session rights object and the authorization data to determine whether the client is authorized to access the data stream, based on comparing the at least one rule against the authorization data, and based on comparing the at least one rule against the at least one purchase option; and transferring a decryption key data and an encrypted data stream to the client when the client is authorized to access the data stream.