Patent Document ID: 8385545
Application ID: 11829647

Base Claim:
1. A subscriber television system comprising: a plurality of conditional access systems (CASs) configured to each supply a control word to a first encrypter for use by the first encrypter to encrypt a first stream of packets with each of the control words, wherein the plurality of CASs are provided by physical equipment in a head end of the subscriber television system, the physical equipment including a random control word generator for providing the control word, wherein each of the control words is generated from information contained in an entitlement control message and information from authorization information, the authorization information stored in a set-top box in the subscriber television system, wherein the entitlement control message comprises frequently changing decryption information; the first encrypter configured to: encrypt the first stream of packets to produce a second stream of packets, each packet of the first stream of packets corresponding to a single encrypted packet in the second stream of packets, and generate a special packet, the special packet containing information to identify which packet in the first stream of packets was encrypted with each control word generated by the plurality of CASs, wherein the first encrypter comprises a physical component module in the head end comprising the physical equipment; and a first decrypter having a secure micro to receive the special packet and configured to decrypt the second stream of packets using the information in the special packet.

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Claim 8:
8. The system of claim 1 , further comprising: a first encryption module; a second encryption module, wherein a first control word from a first encryption CAS is supplied to a first encryption module for encrypting the first stream of packets to produce a first encrypted stream of packets and a second control word from a second encryption CAS is supplied to a second encryption module for encrypting the first encrypted stream of packets to produce a second encrypted stream of packets.