A partial dual encrypted stream utilizing program map tables

A communications facility for encoding and transmitting a partial dual-encrypted program stream, the communications facility comprising:

• existing headend equipment for providing a clear program stream and a first encrypted program stream in accordance with a first encryption scheme, wherein the clear program stream and the first encrypted program stream have associated program map tables including a plurality of program numbers each corresponding to a program, wherein a program number is found in both the clear program stream and the first encrypted program stream;
• and
• an additional device for receiving the clear stream and the encrypted program stream, the additional device comprising:
• a first demultiplexer for demultiplexing the plurality of programs in the clear stream and providing each demultiplexed program to an output of the first demultiplexer;
• a second demultiplexer for demultiplexing the plurality of programs in the first encrypted program stream and providing each demultiplexed program to an output of the second demultiplexer;
• and
• for each of the plurality of demultiplexed programs, an identifier for receiving the demultiplexed program of the clear stream and the corresponding demultiplexed program of the first encrypted stream and for identifying critical packets of the clear program,
• wherein, when a critical packet is identified in the clear program, the identified critical packet is encrypted by a second encryption scheme.

A communications facility for encoding and transmitting a partial dual-encrypted program stream, the communications facility for receiving a clear program stream, the clear program stream including a plurality of programs, the communications facility comprising:

• a first encryptor for receiving the clear program stream and encrypting the plurality of programs according to a first encryption scheme;
• a second encryptor for receiving the clear program stream and encrypting the plurality of programs according to a second encryption scheme;
• a first demultiplexer for demultiplexing the first encrypted plurality of program streams and for providing a plurality of first encrypted programs;
• a second demultiplexer for demultiplexing the second encrypted plurality of program stream and for providing a plurality of second encrypted programs;
• a third demultiplexer for demultiplexing the clear program stream and for providing a plurality of clear programs;
• and
• for each common program number of the first encrypted programs, the second encrypted programs, and the clear programs, an identifier for identifying critical packets in the clear program, and, when a critical packet is identified, for dropping the critical packet of the clear program and passing corresponding critical packets of the first and second encrypted programs.