Patent ID: 8559628

Claim:
A client device for cryptographic sanctioning of secure transmission of media content from a caching server, the client device comprising: a network interface that provides bidirectional data communication with a sanction server and the caching server via at least one network, wherein the network interface transmits a request for the media content to the sanction server, receives second sanction data from the sanction server, transmits second cryptographic data to the caching server, receives first cryptographic data from the caching server and that receives scrambled media content from the caching server; a random number generator, coupled to the network interface, that generates a random number; a client processing module in the client device, coupled to the random number generator and the network interface, that, in response to the second sanction data, generates the second cryptographic data based on the random number and the second sanction data, generates a scrambling control word based on the second sanction data and the first cryptographic data and that descrambles the scrambled media content based on the scrambling control word; wherein the caching server generates the first cryptographic data based on first sanction data received from the sanction server; and wherein the first sanction data, the second sanction data, the first cryptographic data and the second cryptographic data are generated in accordance with an asymmetrical public key cryptography algorithm.