10. A method of encryption in a conditional access system, comprising: receiving a first control word from a first conditional access system (CAS); receiving a second control word from a second conditional access system, wherein the first and second CASs are provided by physical equipment in a head end of a subscriber television system and wherein the first and second control words are generated by a random control word generator in the physical equipment, wherein each of the first and second control words are 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; encrypting a first stream of packets with the first control word and the second control word 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, wherein the encryption is performed by an encrypter, the encrypter comprising a physical component module in the head end comprising the physical equipment; generating 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; receiving, at a secure micro, the special packet; and decrypting the second stream of packets using the information in the special packet.
11. The method of claim 10 , further comprising: determining whether a packet of the first stream of packets is to be encrypted by the first control word or the second control word; and demultiplexing the first stream of packets, wherein the encrypting the first stream of packets with the first control word and the second control word comprises performing in parallel the encrypting with the first control word and the encrypting with the second control word.