Abstract: A method of encoding a packetized digital television signal consistent with certain embodiments involves encrypting a portion of the packets containing the digital television signal according to a first encryption algorithm; encrypting the portion of the packets containing the digital television signal according to a second encryption algorithm; leaving a portion of the packets containing the digital television signal unencrypted; assigning a primary packet identifier to the unencrypted packets; assigning a primary packet identifier to the packets encrypted under the first encryption algorithm; and assigning a secondary packet identifier to the packets encrypted under the second encryption algorithm. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.

Abstract: A Video On Demand (VOD) method consistent with certain embodiments involves processing content to be delivered in a VOD method by selecting first portions of the content for encryption under a selective encryption system and selecting second portions of the content to remain unencrypted. The first and second portions are stored until receiving a request for delivery of the content, the request being from a terminal having decryption capabilities associated with a first decryption method. The first portions are then bulk encrypted to produce encrypted first portions. The encrypted first portions are stored in a buffer. The second portions are queued for delivery to the terminal. A stream of selectively encrypted content is assembled from the encrypted first portions and the second portions. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.

Abstract: A selective encryption encoder has a packet identifier that identifies packets of a specified packet type forming a part of a program. A packet duplicator duplicates the identified packets to produce first and second sets of the identified packets. A PMT (program map table) inserter generates temporary identifying information that identifies the first and second sets of identified packets inserts the temporary identifying information as user private data in a program map table (PMT) forming a part of the transport program specific information (PSI). The data are then sent to and received from a primary encryption encoder to encrypt the first set of identified packets under a first encryption method. A secondary encrypter encrypts the second set of identified packets under a second encryption method. The PSI is then modified at a PSI modifier to remove the temporary identifying information and to correctly associate the first and second sets of identified packets and the unencrypted packets with the program.

Abstract: A multimedia stream head end includes a legacy conditional access (CA) device that fully encrypts the stream using legacy keys. A copy of the stream is sent to a secondary CA device that encrypts only critical packets in the stream using secondary keys to render a partially encrypted stream. The critical packets in the fully encrypted stream from the legacy CA device are obtained and inserted next to the corresponding critical packets in the partially encrypted stream. Thus, only critical packets are encrypted, with encrypted versions being generated by both the legacy CA and secondary CA without the legacy CA knowing which of the packets that it encrypts are “critical”.

Abstract: A selective encryption encoder consistent with certain embodiments of the invention has vertical and/or horizontal stripes encrypted. In one embodiment, packets are examined in the digital video signal to identify a specified packet type, the specified packet type being both packets carrying intra-coded data representing a pattern of horizontal stripes across an image and packets carrying intra-coded data representing a pattern of vertical stripes across an image. The packets identified as being of the specified packet type are encrypted using a first encryption method to produce first encrypted packets. These first encrypted packets are then used to replace the unencrypted packets in the digital video signal to produce a partially encrypted video signal. The packets of the specified type can also be multiple encrypted and replaced in the data stream to produce a multiple encrypted video data stream.

Abstract: An encryption arrangement for multiple encryption of television programs. A system according to embodiments of the present invention multiple encrypts only a portion of the data required for full presentation of a television program to permit coexistence of multiple conditional access encryption systems associated with multiple manufacturer's set-top boxes within a single system. PID mapping techniques are used to distinguish between multiple encryptions. By only encrypting a portion of the program, dramatically less bandwidth is consumed than the alternative of multiple encryption of all program data, thus permitting a larger number of programs to be carried over the same bandwidth while permitting coexistence of multiple conditional access systems in a single cable television system.

Abstract: An encryption arrangement for multiple encryption of television programs. A system according to embodiments of the present invention multiple encrypts only a portion of the data required for full presentation of a television program to permit coexistence of multiple conditional access encryption systems associated with multiple manufacturer's set-top boxes within a single system. By only encrypting a portion of the program, dramatically less bandwidth is consumed than the alternative of multiple encryption of all program data, thus permitting a larger number of programs to be carried over the same bandwidth while permitting coexistence of multiple conditional access systems in a single cable television system.

Abstract: An encryption arrangement for multiple encryption of television programs. A system according to embodiments of the present invention multiple encrypts only a portion of the data required for full presentation of a television program to permit coexistence of multiple conditional access encryption systems associated with multiple manufacturer's set-top boxes within a single system. In one embodiment, only audio data are encrypted leaving video in the clear. By only encrypting a portion of the program, dramatically less bandwidth is consumed than the alternative of multiple encryption of all program data, thus permitting a larger number of programs to be carried over the same bandwidth while permitting coexistence of multiple conditional access systems in a single cable television system.