CONTENT DELIVERY NETWORK HAVING DOWNLOADABLE CONDITIONAL ACCESS SYSTEM WITH PERSONALIZATION SERVERS FOR PERSONALIZING CLIENT DEVICES

摘要

A content delivery network and method employing a DownloadableConditional Access System ("DCAS") includes first and second personalizationservers. A unit key list having unique keys is segmented into differentblocks. Eachblock is encrypted with a separate transmission key corresponding to thatblock suchthat first and second blocks are respectively encrypted with first and secondtransmission keys. The encrypted blocks are communicated to thepersonalizationservers. The first transmission key is communicated to the firstpersonalization serverwithout being communicated to another personalization server such that thefirstserver can decrypt the first block using the first transmission key to accessthe keys ofthe first block. The second transmission key is communicated to the secondpersonalization server without being communicated to another personalizationserversuch that the second server can decrypt the second block using the secondtransmission key to access the keys of the second block.