Method and apparatus for encrypting media programs for later purchase and viewing

The present invention relates to systems and methods for providing video program materials to subscribers, in particular methods and systems for confidentially storing and playing media programs.

This application relates to the following patent applications, all of which are referenced herein. U.S. Patent Application 09 / 620,832 (Invention title VIDEO ON DEMAND PAY PER VIEW SERVICES WITH UNMODIFIED CONDITIONAL ACCESS FUNCTIONALITY, Raynold M.Kahn, Gregory J.Gagnon, David D.Ha, Peter M.Klauss, Christopher P .Curren, Thomas H. James, Agent Certification Number PD-200055, July 21, 2000); U.S. Patent Application No. 09 / 620,833 (Invention title SECURE STORAGE AND RELAY OF MEDIA PROGRAMS USING A HARD-PAIRED RECEIVER AND STORAGE DEVICE, Raynold M.Kahn, Gregory J.Gagnon, David D.Ha, Peter M. Klauss, Christopher P.Curren, Thomas H.James, Agent Certification Number PD-200042, July 21, 2000); US Patent Application 09 / 621,476 (Invention Name SUPER ENCRYPTED STORAGE AND RETRIEVAL OF MEDIA PROGRAMS IN A HARD-PAIRED RECEIVER AND STORAGE DEVICE , Raynold M.Kahn, Gregory J.Gagnon, David D.Ha, Peter M.Klauss, Christopher P.Curren, Thomas H.James, Agent Certification Number PD-200043, 2000 July 21, 2014); U.S. Patent Application 09 / 620,773 (Invention title SUPER ENCRYPTED STORAGE AND RETRIEVAL OF MEDIA PROGRAMS WITH MODIFIED CONDITIONAL ACCESS FUNCTIONALITY, Raynold M.Kahn, Gregory J.Gagnon, David D.Ha, Peter M.Klauss, Christopher P.Curren, Thomas H.James, Agent Certification Number PD-200044, July 21, 2000); U.S. Patent Application 09 / 620,772 (Invention Name SUPER ENCRYPTED STORAGE AND RETRIEVAL OF MEDIA PROGRAMS WITH SMARTCARD GENERATED KEYS , Raynold M.Kahn, Gregory J.Gagnon, David D.Ha, Peter M.Klauss, Christopher P.Curren, Thomas H.James, Agent Certification Number PD-200045, July 21, 2000); U.S. Patent Application No. 09 / 491,959 (Invention name "VIRTUAL VIDEO ON DEMAND USING MULTIPLE ENCRYPTED VIDEO SEGMENTS", Robert G.Arsenault, Leon J. Stanger, Attorney Certification Number PD-980208, January 26, 2000) ..

In recent years, there has been increasing interest in allowing cable and satellite television subscribers to record media programs for later observation. This ability, hereafter referred to as Personal Video Recording (PVR), is to provide video on demand (VOD) or simply to allow subscribers to memorize media programs for repetitive observation and / or archiving purposes. Can be used.

In the past, videocassette tape recorders (VCRs) have been used for such personal video recordings. Recently, however, hard disks similar to those used in personal computers have been used to store media programs for later observation. Unlike VCRs, such devices typically do not include a tuner but are instead coupled to a satellite receiver or cable box. Also, unlike VCRs, these devices are typically used to record digitized content rather than analog video. This difference is both an advantage and a disadvantage.

<p> The advantage of such devices is that they allow long-term memory and multiple regenerations without substantial degradation. Another advantage is that they allow fast fast-moving features such as fast fast forward and rewind. The disadvantage of such devices is that they are similarly free of significant degradation and can make multi-generational copies of program material. This raises the very realistic possibility that multi-generational copies of media programs will be generated and distributed without permission. Due to this possibility, some media providers do not like to allow their media programs to be recorded by such devices.</p><p> To remedy this problem, it is important to protect the stored media programs with strong security and copy control. Current devices do not scramble media programs prior to storage, and they do not store copy protection information. Instead, such devices store the decrypted program content on a storage disk using a paired hardware scheme in which the hard disk controller and the hard disk are paired with each other, especially through a special interface. .. Since the hard disk controller and the disk itself are basically paired together, storage or playback will not work if the disk is ejected and transferred to another player. The weakness of this security scheme is that it relies only on paired hardware to ensure security, and the media programs stored on the disk drive itself are not encrypted.</p><p> Although it is probably possible to simply store the data stream when it is received from the broadcaster for later playback, this technique has different drawbacks. One such drawback is that the permanently stored version of the encrypted data stream infringes copyright and therefore performs a detailed analysis of the data stream itself to determine the encryption technique and code. Is to infringe the copyright of the information that can be used for.</p><p> Systems and methods are needed to securely record broadcast media programs (including impulse purchase pay-per-view programs) to limit the use of playback at a later time. Such systems are used to support Video on Demand (VOD), thus allowing subscribers to instantly purchase media programs and games from set-top boxes without worrying about program start times. To.</p>

<p> In summary, the invention discloses a system and method of storing and retrieving program material for later reproduction. This method receives the receiver ID associated with the receiver key stored in the receiver's memory, determines the pairing key to encrypt the communication between the conditional access module and the receiver, and receives. It includes a step of encrypting the pairing key with the machine key and sending a message containing the encrypted pairing key to the receiver.</p><p> The device comprises a receiver that receives a data stream that transmits a media encryption key and a media program encrypted according to the encrypted media encryption key, and a conditional access module that can be combined in communication with the receiver. It is equipped. The receiver is equipped with a first decryption element that decrypts the message from the conditional access module according to the pairing key, the message is equipped with a media encryption key, and the conditional access module is equipped with an encrypted media encryption key. It includes a second decryption element for decryption and a first encryption element for encrypting a message by a receiver according to a pairing key.</p><p> One object of the present invention is the reception of broadcast media programs, including impulse pay-per-view (IPPV) programs, which can be regenerated and stored on a storage medium to allow for limited replay for later time use. And to decipher. The data itself may be stored in a storage device for a short period of time, but the playback of the media program is realized by high-speed operation functions such as fast-forward, rewind, high-speed fast-forward, high-speed rewind, frame advance, and pause function. Can be done.</p><p> Another object of the present invention is to provide a PVR function for recording from a storage medium, delayed playback, and high-speed operation of the IPPV media program without the need to purchase the IPPV media program in advance. This allows the IPPV media program to be purchased and observed in the user's leisure time without the need for the IPPV media program to be purchased prior to storage. Ideally, such a system would allow the user to select an IPPV media program from storage and receive limited playback rights.</p><p> Yet another object of the present invention is to perform pairing between the elements of the storage medium and the subscriber's IRD to ensure that playback of the media program from the storage device is only allowed by the appropriate IRD. is there.</p><p> Yet another object of the present invention is to provide a secret protection means for storing broadcast data streams (including IPPV and games) in a data storage device while providing appropriate copy protection.</p><p> Yet another object of the present invention is to provide a system and method for processing media programs and other data archiving and retrieval in the event of a data storage device failure.</p><p> Yet another object of the present invention is to provide a system and method that allows the purchase of a media program to be stored in a manner similar to that used in real-time non-wireless programs.</p><p> Yet another object of the present invention is IPPV without incurring an initial hour fee with the option of purchasing or canceling the media program, whether the program is retrieved from storage or obtained from real-time broadcasts. It is to provide a system that gives a growth stage to a system that allows media programs to be previewed.</p><p> Yet another object of the present invention is to achieve all of the above without the need for substantial changes to the conditional access module hardware and / or software.</p><p> The present invention eliminates the problem of increasing unauthorized digital copies of media programs by using strong cryptographic methods. Furthermore, the present invention ensures that the stored material is not distributed, as such decryption of the material can only be properly performed by an encrypted IRD.</p>

With reference to the drawings, the same reference numerals throughout the drawings represent the same corresponding parts. In the following description, reference will be made to the accompanying drawings, which form part of the description and illustrate some embodiments of the invention by way of example. It will be appreciated that other embodiments may be utilized and that structural changes are made without departing from the technical scope of the invention.

[Media Program Distribution System] FIG. 1 is a diagram showing an outline of the video distribution system 100. The video distribution system 100 communicates with the uplink center 104 via terrestrial or other link 114 and with the receiver / decoder (IRD) 132 integrated at the receiver 130 via the public switched telephone network (PSTN) or other communication link 120. It includes a control center 102. This control center 102 provides program material to the uplink center 104 and media programs to subscriber 110, including pay-per-view (PPV) program services, including billing and decoding of related video programs. Coordinate with receiving station 130.

The uplink center 104 receives the program material and program control information from the control center 102, and uses the uplink antenna 106 to transmit the program material and control information to the satellite 108. Satellite 108 receives and processes this information and transmits the video program and control information over the downlink 118 to the IRD 132 of the receiving station 130. The IRD 132 receives information using the subscriber antenna 112 that it is coupled to communicate with.

The video distribution system 100 can include multiple satellites 108 to provide wide ground coverage, provide additional channels, or provide additional bandwidth per channel. In one embodiment of the invention, each satellite comprises 16 transponders for receiving and transmitting program material and other control data from the uplink center 104 and feeding it to the subscriber 110. However, by using data compression and multiplexing techniques, the channel capacity is further increased. For example, two satellites 108 operating together can be received and broadcast over 150 normal (non-HDTV) audio and video channels with 32 transponders.

Although the invention disclosed herein is described with reference to the satellite-based video distribution system 100, the invention is also practiced by terrestrial-based transmission of program information by traditional broadcasting means, cables or other means. To. Moreover, as described above, the different functions collectively assigned between the control center 102 and the uplink 104 can be reassigned as desired without departing from the technical scope of the invention.

Although described above with respect to one embodiment in which the program material transferred to the subscriber is a cinematic video (and audio) program material, the aforementioned method comprises pure audio information or similarly any other type of data. Can be used to transfer program material.

FIG. 2 is a block diagram showing a typical uplink structure of a single satellite 108 transponder showing a mode in which a video program material is uplinked to satellite 108 by a control center 102 and an uplink center 104. Figure 2 shows three video channels (which can each be augmented by one or more audio channels for high fidelity music, soundtrack information, or secondary audio programs for transmitting foreign languages). , Shows data channels from computer data source 206.

Video channels are provided by the video material program source 200A-200C (collectively referred to as the video source 200). Data from each video program source 200 is given to encoder 202A-202C (hereinafter collectively referred to as encoder 202). Each encoder receives a presentation time stamp (PTS) from controller 216. PST is a wraparound binary time stamp used to ensure that video information is properly synchronized with audio information after encoding and decoding. The PTS time stamp is transmitted in each I frame of the MPEG coded data.

In one embodiment of the invention, each encoder 202 is a second generation moving picture expert group (MPEG-2) encoder, but other decoders performing other coding techniques can be used as well. Data channels can be subjected to similar compression schemes by encoders (not shown), but such compression is usually not required or performed by computer programs in computer data sources (eg, photographic data is typical). Compressed into * .TIF or * .JPG files before sending). After being encoded by the encoder 202, the signal is converted into a data packet by the packetizing device 204A-204F (hereinafter collectively referred to as the packetizing device 204) associated with each source 200, 206-210.

The data packet is a reference from the system clock 214 (SCR), a control word (CW) generated by the conditional access control device 208, and a system channel identifier (SCID) that associates each data packet broadcast to the subscriber with the program channel. Assembled using vessel 210. This information is transmitted to the packetizing device 204 for use in generating data packets. These data packets are then multiplexed, encoded, modulated, and transmitted into serial data. A special packet known as a control word packet (CWP) that contains control data containing a control word (CW) and other control data used in support for conditional access to program material is also encrypted. It is converted and sent.

A in FIG. 3 is a diagram of a typical data stream. The first packet segment 302 contains information from video channel 1 (eg, data coming from the first video program source 200A). The next packet segment 304 contains computer data information obtained, for example, from computer data source 206. The next packet segment 306 contains information from video channel 5 (from one of the video program sources 200) and the next packet segment contains information from video channel 1 (again from the first video program source 200A). I'm out. Therefore, the data stream contains a series of packets from any one of the data sources in the order determined by controller 216. The data stream is encrypted by encryption module 218, modulated by modulator 220 (typically using QPSK modulation scheme) and fed to transmitter 222, which transmitter antennas 106 the modulated data stream. Broadcast to the satellite via frequency bandwidth.

Subscriber 110 receives the media program through the subscriber receiver or IRD 132. Using SCID, IRD132 reconstructs the packet to play the program material for each channel. As shown by A in FIG. 3, the zero packets generated by the zero packet module 312 are inserted into the data stream as desired.

B in FIG. 3 is a diagram of data packets. Each data packet (eg 302-316) is 147 bytes long and contains multiple packet segments. The first packet segment 320 contains 2 bytes of information containing the SCID and flags. SCID is a unique 12-bit number that uniquely identifies the data channel of a data packet. The flag is used to control whether the packet is encrypted or not, and contains 4 bits used to control the key that must be used to decrypt the packet. The second packet segment 322 consists of a 4-bit packet type indicator and a 4-bit continuous counter. The packet type identifies the packet as one of four data types (video, audio, data or zero). When combined with SCID, the packet type determines how the data packet is used. The contiguous counter increments once for each packet type and SCID. The next packet segment 324 consists of 127 bytes of payload data, which is part of the video program provided by the video program source 200. The final packet segment 326 is the data required to perform forward error correction.

Media Program Encryption Media programs are encrypted by encryption module 218 prior to transmission to ensure that they are received and observed only by authorized subscribers. Each media program is subsequently encrypted according to a letter-number encryption key called a control word (CW). This can be achieved by a variety of data encryption techniques, including symmetric algorithms such as the Data Encryption Standard (DES) and asymmetric algorithms such as the Rivest-Jameel-Aldreman (RSA) algorithm.

To decrypt the media program, 110 subscriber IRD132s must access the CW. To maintain security, CWs are not sent in clear text to IRD132. Instead, the CW is encrypted before being sent to the subscriber's IRD132. The encrypted CW is sent to the subscriber IRD132 in a control word (data) packet.

In one embodiment, the CWP data, including the CW, is subsequently encrypted and decrypted via what is called an input / output (I / O) unreadable algorithm.

An I / O unreadable algorithm is an algorithm given to an input data stream to generate an output data stream. The input data stream uniquely determines the output data stream, but the algorithm chosen is such that its characteristics cannot be deciphered from the comparison of multiple input and output data streams. The security of this algorithm can also be increased by adding non-stationary (ie, these change as a function of time) additional functional elements. When the same input stream is given to such an algorithm, the output stream given at a given point in time can be different from the output stream given at different times.

As long as the encryption module 218 and IRD132 share the same I / O unreadable algorithm, the IRD132 can decrypt the encrypted CWP information to retrieve the CW. Using CW, IRD132 can decrypt the media program so that it can be given to subscriber 110.

Further, to prevent copyright infringement, the control data required to decrypt the data packets and assemble them into an observable media program may change over time (to decrypt a particular media program). The validity of CWP control data in CWP changes over time). This can be done in various ways.

For example, since each CWP is associated with SCID for each medium program, the SCID associated with each CWP changes over time.

Another way to construct time-varying control data is to associate time stamps with received data streams and CWP control data. In this case, proper decoding of the CWP to generate the CW requires a proper relationship between the time stamp for the data flow and the control data of the CWP. This relationship can be defined, for example, by modifying the decoding method used to generate the CW from the CWP according to the received time stamp on the data stream. In this case, if the time stamp of the received data stream does not match the expected value, the wrong decoding method is selected and no suitable CW (for decoding the program material) is generated. However, if the time stamp of the received data stream matches the predicted value, then the appropriate decoding method is selected and the CWP decoding method yields the appropriate CW.

Pay-Per-View Service The data needed to receive and observe pay-per-view (PPV) media programs is stored in CWP and another data packet known as the Purchase Information Parcel (PIP). ing. CWP and PIP will be broadcast to subscribers in real time via the video distribution system 100. CWP is used by IRD132 to search PPV media programs as described below.

In general, PPV services can include operator-assisted pay-per-view (OPPV) and impulse pay-per-view (IPPV) services. When requesting OPPV services, subscriber 110 must predetermine that he wants access to a particular media program. Subscriber 110 then calls an entity such as Control Center 102 to request access to the media program. When requesting an Impulse Pay-Per-View Service (IPPV), Subscriber 110 moves the cursor over the viewer channel associated with the desired media program while observing the program guide and selects Enter. After the decision and right to purchase the PPV program has been confirmed (eg by channel lockout, rating limit, purchase limit check), a purchase information parcel (PIP) will be received for future use (more on this below). ) Stored in the subscriber's conditional access module 406. Conditional access module 406 associates CWP with PIP information, confirms that subscriber 110 is given access to the media program, and uses PIP with CWP to decrypt the media program.

[Receiving and decoding raw media programs without conditional access modules and IRD pairings] Figure 4 is a simple block diagram of IRD132. The IRD 132 receives and decodes the media program broadcast by the video distribution system 100. These media programs are streamed to IRD132 in real time and include, for example, video, audio or data services.

The IRD132 can be coupled to the Conditional Access Module (CAM) 406 in communication. The CAM406 is typically configured in a smart card or similar device, which is given to the subscriber 110 to be inserted into the IRD132. The CAM 406 interfaces with the Conditional Access Confirmation Device (CAV) 408, which performs at least some of the functions necessary to ensure that the subscriber 110 has the right to access the media program.

The IRD132 has a tuner 410, a transfer and demultiplexing module (TDM) 412 that operates under the control of a microcontrol unit and associated memory 414, and a source decoder 416 and a random access memory (RAM) 418 coupled by communication. It is equipped with a user I / O device for receiving a command of the subscriber 110 and giving output information to the subscriber.

Tuner 410 receives a data packet from the video distribution system and feeds the packet to the TDM412. Using the SCID associated with each media program, the TDM412 reassembles the data packets according to the channel selected by subscriber 110 and uses the CW key to decrypt the media program. The TDM412 consists of a single secret protection chip that is communicated to the microcontrol unit and memory 414.

Once the media programs have been decoded, they are given to the source decoder 416, which decodes the media program data according to the MPEG or JPEG standard as appropriate. The decrypted media program is then fed to a D / A converter (if necessary) and may include a media program presentation device such as a television, audio system, computer, or media storage device such as a hard drive. it can. At the source, the coder 416 uses RAM418, which is coupled by communication to perform these functions.

The CW key is obtained from CWP using CAV408 and CAM406. TDM412 feeds CWP to CAM406 via CAV408. The CAM406 uses an I / O unreadable algorithm to generate a CW that is returned to the TDM412. The TDM412 uses CW to decrypt media programs. For most IRD132s, the CAV408 and CAM406 can decrypt one video / audio / data media program at a time.

As mentioned earlier, to prevent potential piracy, the CWP control data used to decrypt a particular media program changes over time, thereby a media program with the appropriate timestamp. Generate only the appropriate CW when applied to. In this case, the CAM 406 can select and / or control the decoding method (eg, I / O unreadable algorithm) according to the time stamp associated with the data stream transmitting the media program. If the media program is well separated in time, improper decoding methods will be used and no suitable CW will be generated to decode the media program.

In addition, details regarding the encryption and decryption of media programs can be found in US Patent Application No. 09 / 491,959 at the same time, which is hereby referenced.

[Pairing a Conditional Access Module with an IRD] To prevent copyright infringement, the present invention operates a pair of a conditional access module (CAM) 406 and an IRD 132, whereby each IRD 132 operates with the specified CAM 406. And each CAM406 only works with the specified IRD132. This is achieved by encrypting the communication between the CAM 406 and the IRD 132 according to the pairing key generated from the IRD 132's secret receiver key.

FIG. 5 is a functional block diagram of the paired CAM406 and IRD132. As described above, the CAM 406 includes a decoding element 502 (hereinafter also referred to as an EI decoding element) that executes an I / O unreadable algorithm, an encryption element 506 (hereinafter also referred to as an AES encryption element), and a memory 504. I'm out. In one embodiment, the encryption element 506 is a new type of encryption standard (AES) encryption element, but other encryption methods and algorithms can also be used.

IRD132 includes transfer module 412 and security module 508. The transfer module 412 and security module 508 are configured on an integrated circuit (IC) separate from the other circuits of the IRD 132 and can be sealed to prevent fraud. The transfer module 412 and the security module 508 can be configured as separate ICs or the same IC.

Security module 508 includes decoding element 510, which decrypts communications transmitted from conditional access module 406 and provides the results of these decrypted communications to transfer module 412. The decoding element 510 can encrypt the content and copy control information to generate a copy protection key (CP) as described below, or otherwise combine with the family key 518. The decryption element 510 is composed of separate modules for encryption and decryption, if desired.

Security module 508 includes memory 512 to store keys and other information. In one embodiment, the memory 512 employs fraud prevention means in which the contents of the memory 512 cannot be read and given to the security module 508 to the outside (for example, the contents are not readable by the user). This feature prevents compromise of keys stored in memory 512. The memory 512 may also be a volatile memory.

In one embodiment, security module 508 feeds a control word (CW) directly into the CW cache of transfer module 412 via memory access (DMA). Therefore, it is not possible to output or input CW by the system bus. This cryptographically outputs the CW output of the CAM406 to the security module, as the encrypted control word EPK (CW) from that CAM406 can only be decrypted by the receiver 132 that contains the appropriate receiver key 514. Connect to 508 (make a "pair").

The keys stored in the memory 512 include, for example, a pairing key 516, a family key 518, and a receiver key 514. In one embodiment of the invention, the receiver key 514 is pre-installed and given to the security module 508 (and thus the IRD132) when the IRD132 is given to the subscribing user. The receiver key 514 is preferably not readable by the user and is unique to the IRD 132 and is unique to the serial number 532.

The decoding element 510 sends the decrypted control word and copy protection (CP) session key to the transfer module 412, where the key is temporarily stored for later use. The decoded control word (CW) is given to the first transfer chip decoding element 524 to allow the media program stream to be decoded. The resulting decrypted media program stream can be a presentation device (such as a television, monitor, computer or audio system), a storage device (such as a readable / writable CDROM or DVD or hard drive), or observation or storage. Can be given to networks elsewhere for.

In one embodiment, the IRD132 is communicated to a second IRD532 (hereafter referred to as the "daughter IRD"). The daughter IRD can be used to request a media program received or played by the IRD 132, thus allowing the media program to be played elsewhere in the home. Preferably the daughter IRD 532 does not contain long-term storage capacity (eg no hard disk) and the daughter IRD requests storage of media programs and retrieval from IRD 132. The daughter IRD532 can be coupled to the primary or master IRD 132 by communication via any communication link or network (LAN) or other digital communication medium, including a direct coaxial connection.

Returning to the transfer module 412 of FIG. 5, the CP key is used by the decryption element 526 and the encryption element 528 to encrypt and decrypt the data stored and retrieved from the storage device or network 530.

One feature of the invention allows pairing of the conditional access module 406 with the IRD 132 and thus prevents any conditional access module 406 from being used with any IRD 132.

Control center 102 can choose to change the pairing key (PK) when desired. This can be done randomly as a security precaution or scheduled to revoke the user's right to use IRD132.

[Pairing of conditional access module and IRD operation] 6A and 6B are diagrams showing how the conditional access module 406 is paired with the IRD 132. After the subscriber 122 purchases and installs the IRD 132 and associated hardware, the user 122 supplies the control center 102 with a unique identifier for the IRD 132 (such as serial number 532). This can be achieved by the public switched telephone network (PSTN), the Internet, mail, or any other communication medium. The IRD-specific identifier 132 is associated with receiver key 514. This association takes place in the IRD 132 itself and is known to the control center 102. The control center 102 receives the IRD-specific identifier 132 as shown in block 602 and is used to encrypt the communication between the conditional access module 406 and the IRD 132 as shown in block 604. Determine the pairing key (PK) to be paired. The pairing key PK is then encrypted with the receiver key 514 (to generate the ER (PK)) as shown in block 606. As shown in block 608, a message containing the pairing key (PK) and a pairing key encrypted by the receiver key 514 (ER (PK)) are generated. The message is then encrypted to generate an EI (PK, ER (PK)) as shown in block 610. In the embodiments shown, the message is encrypted according to the I / O unreadable algorithm described above (decrypted by the conditional access module 406), but other encryption methods may be used as well. it can. The encrypted message is then sent (via satellite 108, terrestrial transmitter, telephone line, internet, or other medium) to IRD132, where it is received as shown in block 614. The transfer module 412 transmits a data packet to the conditional access module 406 for decryption together with the encrypted message EI (PK, ER (PK)).

Using the decoding element 502 in the conditional access module 406 (eg, by an application of the I / O unreadable algorithm), the message is decoded as shown in block 616. The pairing key 516 is stored in memory location 534 of conditional access module memory 504, as shown in block 618. The encrypted pairing key ER (PK) is also given from conditional access module 406 to security module 508, as shown in block 620. This is not exposed as the message is encrypted according to receiver key 514.

The encrypted pairing key ER (PK) is decrypted by the decryption element 510 of the security module 508 using the receiver key 514. This is shown in block 622. The recovered pairing key is then stored in the IRD 132 of the secret protection memory 512. This pairing key 516, stored in both the IRD 132 and the conditional access module 406, is used to encrypt the communication between the conditional access module 406 and the receiver 132. All or a subset of such communications can be encrypted when desired. In one embodiment, all communications required to allow the user to observe the media program are encrypted.

In the above description, a message with a pairing key (PK) and an encrypted pairing key ER (PK) was encrypted before being sent to the IRD 132. However, if no additional security is required, the message does not need to be encrypted in order to carry out the present invention. Moreover, the present invention can be effectively implemented even if the receiver key is not completely unique. For example, the receiver key is one of 10,000 possible receiver keys. In this case, the probability that the receiver key will match a particular pairing key is 1: 10,000 (as described below), which is sufficient to prevent unauthorized use. In this context, substantive peculiarities instead of absolute peculiarities are all that is required for sufficient security.

FIG. 7 is a diagram further showing the memory of the pairing key 516 of the IRD 132.

[Pairing the operation of the storage device and the IRD] The present invention also performs pairing in the operation between the storage device 530, the IRD 132, and one or more daughter IRD 532. It is assumed that the media program is effectively not stored in plaintext in storage. Pairing of storage device 530 and IRD132 is achieved by using a family key (FK).

FIG. 8 is a diagram showing the memory of the IRD132 family key (FK) 518. Unlike the pairing key (PK) 516, which is used to pair the IRD132 with the conditional access module 406, the family key 518 encrypts the information written to and / or read from the storage device 530 and / or network. Used to obtain a copy protection (CP) key used for encryption and decryption, basically pairing the storage device with the IRD132. The Family Key (FK) 518 can be used to generate a copy protection key (CP) that is used to encrypt the contents and can be used with a large number of boxes. For example, in a box network containing a "parent" IRD132 and multiple daughter IRD532s, any daughter IRD532 will look up encrypted program information as long as a family key (FK) 518 is available for the daughter IRD532. , Information can be deciphered. Unlike the pairing key (PK) 516, the family key (FK) 518 is typically not stored in the CAM406, but is stored in the secret protection memory 512 of the security module 508 in the IRD132. A version of Family Key (FK) 518, encrypted according to receiver key 514 (and encrypted according to the I / O unreadable algorithm), is transmitted by satellite 108 to IRD132 and passes through transfer module 412. , (Decrypt if encrypted according to the I / O unreadable algorithm) is transmitted to CAM406 and then to security module 508. Using the receiver key (RK) 514, security module 508 decrypts the family key (FK) 518 and stores it in secret memory. The family key (FK) 518 is also encrypted with the pairing key (PK) before being sent to the IRD 132, if desired.

FIG. 9 is a diagram showing an operation that can be performed when a data stream having a media program in the IRD 132 is received and the media program is given by the presentation device 530. As mentioned above, the media program is encrypted according to one or more media encryption keys (eg control words) so that the control words (CW) are required to decrypt and give the media program for observation. .. The IRD132 receives an encrypted media program and a control word that is encrypted according to the I / O Unreadable Algorithm (EI (CW)). Transfer module 412 transmits these encrypted control word EI (CW) to conditional access module 406, where they are decrypted by decoding element 502, thus producing control word (CW) 536. The control words are then encrypted according to the pairing key (PK) 516 stored in memory 534 of conditional access module 406, and these encrypted control words EPK (CW) are sent to security module 508 of IRD132. Will be sent. Using the previously stored pairing key (PK) 516, the decryption element 510 of the security module 508 decodes the control words (CW) so that they are stored in the transfer module memory 520 (eg cache). Give to transfer module 412. The control word (CW) is then matched with the associated data packet containing the media program and given to the decoding element 524. The decoding element 524 decodes the media program, and the media program is given to a presentation device 530 such as a television. In this embodiment, the conditional access modules 406 and IRD132 are encrypted according to a unique key (pairing key 516) shared by the CAM 406 and IRD 132 in the control word (CW) required to decrypt the media program. Note that they are paired together in the sense given in the form from CAM406 to IRD132.

FIG. 10 is a diagram showing an operation performed when a transmitted media program is stored in a storage device for later playback. First, the IRD 132 receives a data stream containing a media program encrypted according to a media encryption key (CW). The encrypted media program is decrypted by the decryption element 524. The copy protection key is generated and stored in the transfer module memory 520. Using the copy protection key, the encryption element 528 encrypts the data stream decrypted by the decryption element 524. The encrypted data stream is then stored in storage device 530, which has locally accessible IRD 132. In one embodiment, the storage device is a hard drive inside the IRD 132. The storage device may also be located in another device that is coupled and communicates with the IRD 132.

FIG. 10 shows one embodiment of an embodiment in which an encrypted media program is decrypted and re-encrypted by the pairing key 516 to pair the conditional access module 406 and IRD 132 in operation. An encrypted media encryption key EI (CW) is given to the conditional access module 406 via the transfer module 412, where they are decrypted by the I / O unreadable algorithm 502. The result is a media encryption key (CW). The media encryption key (CW) is re-encrypted according to the pairing key (PK) 516 to generate the re-encrypted media encryption key EPK (CW). The re-encrypted media encryption key EPK (CW) is given to security module 508, where it is decrypted using decryption element 510 and pairing key 516 to provide the media key (CW). The media encryption key (CW) is given to the transfer module 412, where it is cached in storage 520 and used to decrypt the media program.

FIG. 10 also shows one embodiment in which a copy protection key is generated. As shown in FIG. 10, the CP key is generated by combining the (typically unencrypted) Content Identification (CID) with the family key 518 stored in security module 508. The CP key therefore essentially contains information about the stored media program and copy control information. The CID information is sent to the decoding element 510 by the family key 518 to generate the CP key.

The CP key is then stored in memory 520 of the transfer chip, where it is used to encrypt the media program material decrypted by the decryption element 524.

Content identification information (CID) is unique to each media program. In one embodiment, the CID is a simple serial number. This embodiment minimizes the memory requirement to store and maintain the CID. In another embodiment, the CID contains information such as the title of the media program and one or more artists. The CID also contains running time, copyright information, actors, directors, or rating information for media programs. This information can be entered by the user or obtained from the program guide. Since it is very unlikely that any media program will have the same title and other information, the CID forms such information while maintaining its uniqueness.

In one embodiment, the CID does not contain perceptible information so that it can be stored anywhere in the system. In one embodiment, the CID is stored in storage along with the media program. For example, if the storage device is a hard disk drive, the CID is contained in the same file as the media program, stored in the same brochure as the media program, or simply associated with the media program via a lookup table. When a particular stored media program is played, the CID is read from the hard disk and used to regenerate the CP key.

In another embodiment, the CID information includes copy control information (CCI), which can be used to control the state in which the associated media program can be copied or played. For example, CCI indicates that a media program is played only once, not an indefinite number of times. CCI also indicates when a media program can be played. This feature is useful in that it allows the media program to be recorded and not played until such playback rights are approved by the copyright holder or rights.

In embodiments where the CID information also includes CCI, it is useful to store the information in storage or otherwise compromise and encrypt the CID information with a convenient key before exposing it. .. The CID information can be encrypted, for example with the family key 518, before being stored on the hard drive.

After encryption with the CP key, the media program material is no longer protected (encrypted with the family key 518) and is either stored in storage 530 or given to the daughter IRD across the network. Since the daughter IRD accesses the family key, the daughter IRD decodes the media program and gives it to the user if desired.

After at least a portion of the encrypted media program is stored in storage device 530, it can be read from storage device 530 and given to the user for observation. This can be started, for example, by giving a user command requesting playback of the media program. This user command contains an identifier indicating that the media program stored in the storage device 530 is involved. Using this information, CID / CCI information is obtained from storage (eg, storage 530, which stores media programs), decrypted (if it was encrypted before storage), and uses Family Key 518. Is given to the decoding element 510 for processing. As a result, the CP key resembles the key used to encrypt the media program before storing it in storage 530. CP key is then the security module 510 transfers module provided to Le 412 is used by the decryptor 526 to decrypt wherein the stored reading is media program from the storage device 530. The decrypted media program is then given to the presentation device 530.

Memory of unpurchased pay-per-view media programs Figure 11 shows the actions that can be taken to remember unpurchased pay-per-view media programs for later purchase and observation. It is a figure. A data stream containing a media program that is encrypted according to the media encryption key (CW) is received. A copy protection key (CP) is generated and used to further encrypt the data stream, including encrypted media and the encrypted media encryption key EI (CW). The data stream (with the media program) is basically double encrypted with a media encryption key (CW) and a copy protection key (CP) and then stored for purchase and observation for the convenience of the user. Can be done. As shown in Figure 11, the CP key is generated from the CID and family key (FK) 518 as described above.

[Pay-per-view media program search and playback] FIG. 12 is a diagram showing operations that can be performed to play a PPV media program that has not been stored and purchased. After the user instructs the system to play the stored PPV media program, the copy protection (CP) key is generated from the content identifier (CID) and family key (FK) 518. A copy protection (CP) key is stored in cache 520 of transfer module 412 and is used to decrypt the doubly encrypted data stream read from storage 530. The resulting output is the media program (still encrypted by the media encryption key (CW) and still the encrypted media program encryption key EI (CW)).

Basically, this output is the same as the output of a real-time non-radio broadcast. The media encryption key (CW) does not change over time (it changes over time, so each media encryption key can only be used by some data packets with the media program) Both the media encryption key and the media program To the same extent "obsolete", therefore the media encryption key (CW) is used to decrypt the encrypted media program just as it would be if the media program were decrypted and played non-wirelessly in real time. Can be done. For this reason, PPV billing can be performed on the CAM406 without substantial changes. Before decrypting the encrypted media key EI (CW), the CAM 406 records the information required to charge the user to observe the recorded program and requires that charge information. When it is, it is sent to the control center 102.

The encrypted media key EI (CW) is then provided to the CAM406, where it is decrypted by an I / O unreadable algorithm and paired key to generate a re-encrypted media encryption key EPK (CW). Re-encrypted by (PK) 516. The re-encrypted media encryption key is given to security module 508, which decrypts the re-encrypted media encryption key EPK (CW) to generate the media encryption key (CW). The media encryption key (CW) is given to the transfer module 412, where it is cached and used to decrypt the encrypted media program. The media program is in clear text and can be given to the media presentation device 530.

Specially performs the so-called "fast operation" characteristic in which the user desires high speed fast forward, rewind, scan fast forward, reverse scan or pause of a media program presentation. To ensure that the media program is uncompromising, the present invention does not remember any important part of the plaintext of the media program, even when such fast operating characteristics are invoked. Instead, the media program is re-encrypted according to the copy protection (CP) key, retrieved, and decrypted according to the copy protection key (CP), as shown in FIG. The copy protection key is generated from the family key 518 and CID.

The present invention can also be used to store and retrieve a wide range of digital media, including music, computer programs, computer data, photographs and videos. For example, the present invention can be used to purchase just one song from an entire album or from a particular album.

[Purchase and playback of digital media] FIG. 13 is a diagram illustrating operations that can be used to purchase or obtain the right to purchase such digital media. The data object 1302 is given to the control center 102, where the control word (CW) is sent to the digital media control word (CW (DM)) 1304 in a manner similar to the method used to encrypt the media program described above. Therefore, it is encrypted by the encryption element 1306 or 218. The result of this operation is the data object EI (DO) and an encrypted version of one or more digital media control word packets (digital media CWP) 1308. It is further encrypted by the encryption element 1312 according to the data service reservation control word (CW (DSS)) 1310. The result is a data service reservation control word packet (CWP (DSS)) and a data object encrypted according to the first digital media control word (CW (DM)) and data service reservation control word CW (DSS). is there. The doubly encrypted data object, along with the CWP (DSS), will be uplinked to satellite 108 for transmission to IRD132.

FIG. 14 is a diagram illustrating a mode in which the selected IRD 132 can receive encrypted data objects that have not been purchased for storage and subsequent retrieval. The data service reservation control word packet CWP (DSS) is given to the CAM405 via the forwarding module 412. Using an I / O unreadable algorithm, CWP (DSS) is decrypted to generate a data service reservation control word (CW (DSS)). The data service reservation control word (CW (DSS)) is encrypted according to the pairing key 516 stored in the CAM 405 and sent to the security module 508 of the IRD 132. The encrypted data reservation control word EPK (CW (DSS)) is then decrypted by the pairing key (PK) 516 by the decryption element 524 of the security module 508, and the digital service reservation control word (DSS (CW)) is decrypted by the transfer module. It is cached in the storage device 520 available to the decoding element 524 of the 412.

The data service reservation control word CW (DSS) then streams the data to generate a digital media control word packet (CWP (DM)) and a data object encrypted by the digital media control word (CW (DM)). Used to decrypt (essentially removes the encryption layer associated with the Digital Services Reservation Control Word (DSS (CW))). After this decryption, the rest of the data stream is still encrypted according to the digital media control word.

The data stream is further encrypted according to the copy protection (CP) key generated from the family key 518 and CID. As a result, the further encrypted data stream is stored in the data storage device or given to the network 530.

FIG. 15 is a diagram showing an operation used to purchase and read an unpurchased data object. The behavior shown in FIG. 15 is basically similar to the behavior shown in FIG. The encrypted data stream is read from the network or storage 530 and decrypted by a copy protection (CP) key (generated by the CID and family key (FK) 518). The result is a data object encrypted according to the Digital Media Control Word (CW (DM)) and an encrypted version of the Digital Media Control Word EI (CW (DM)). An encrypted version of the digital media control word is given to the CAM406, where it is decrypted and re-encrypted according to the pairing key stored in the CAM406. The re-encrypted digital media control word EPK (CW (EM)) is given to security module 508, where they are decrypted to generate the digital media control word CW (DM). The digital media control word CW (DM) is stored or cached in the storage device 520 of the transfer module 412 and then given to the decoding element 524. Using these control words, decoding element 524 produces a plaintext version of the data object, which is stored in storage (ie, disk drive), given to the IRD 132 for immediate use, or the data object. It is connected to the presentation device and communicated. As just described in FIG. 12, if fast operation is desired, the data object is encrypted with the CP key before storage and decrypted with the CP key for playback.

The behavior shown in FIGS. 12 and 15 allows the billing information regarding the purchase of the PPV program to be stored confidentially in the CAM406, which in this CAM406 it is confidentially recalled (eg, for example). It can be sent to the control center (via PSTN). However, in many cases the CAM406 has a limited amount of memory, which is exhausted by multiple PPV purchases in a short period of time, thus requiring more frequent transmission of billing information. However, if a large number of media programs or data objects are downloaded in a short period of time, such data objects will usually have lower values than typical PPV data objects. For example, the above description allows the user to download selected songs from an album for assembling a compact disc (CD). However, in doing so, the user requests a large number of low-valued data objects (individual songs) instead of a small number of high-valued data objects (whole album).

The present invention purchases and downloads low value data items without exhausting the memory of the CAM406. This is realized by storing the billing information in the storage device 530.

FIG. 16 is a diagram showing an operation used to receive, store, and play back low value digital media. The received digital media is encrypted according to the control word (CW). The encrypted control word (EI (CW)) is given to the CAM406, where it is decrypted and re-encrypted according to the pairing key. The encrypted control word EPK (CW) is given from the CAM 406 to the security chip, where the encrypted control word is decrypted to generate the control word (CW) and cached or cached in storage 520 of transfer module 412. It will be remembered. The media program is then encrypted according to a copy protection (CP) key (using the techniques described above).

When a user wants to observe or otherwise use a media program or data object, a copy protection (CP) key is generated from the CID and family key and is used to decrypt the encrypted media program. When the CID is accessed, information about the purchase of the media program is stored, which allows the user to be charged for the use or observation of the media object.

Unlike the embodiments described in FIG. 15, purchasing a stored media program does not require modification of the CAM406. Instead, the purchase information is stored in a less confidential location than the CAM406. The security of purchase and billing information is reduced in this embodiment, but the need for the CAM 406 to store large amounts of billing information is reduced.

[Conclusion] The above description of preferred embodiments of the present invention has been made for purposes of illustration and explanation. The present invention is not intended to be exhaustive or limited to the exact forms described herein. Numerous deformations and changes are possible in light of the above considerations. The technical scope of the present invention is not limited by this detailed description, but is intended to be limited by the claims. The above description, examples and data provide a complete description of the manufacture and use of the structures of the invention. The present invention is defined by the claims, as many embodiments of the invention can be made without departing from the technical scope of the invention.

<figref num="1">Explanatory diagram of the outline of the video distribution system.</figref><figref num="2">A block diagram of a typical uplink structure showing how a video program material is uplinked to a satellite for transmission to a subscriber using a single transponder.</figref><figref num="3">The figure which shows the typical data stream received from the satellite, and the data packet structure.</figref><figref num="4">A block diagram showing a high level block diagram of the IRD.</figref><figref num="5">A block diagram showing the functional relationship between a conditional access module, IRD, security and the transfer of its transfer chip.</figref><figref num="6A">A flow diagram showing the procedure by which a conditional access module is paired with an IRD.</figref><figref num="6B">A flow diagram showing the procedure by which a conditional access module is paired with an IRD.</figref><figref num="7">The figure which shows the memory of the pairing key of IRD.</figref><figref num="8">The figure which shows the memory of the family key of IRD.</figref><figref num="9">An explanatory diagram showing an operation that can be performed when receiving a data stream having an IRD media program and feeding the media program.</figref><figref num="10">The figure which shows one Embodiment of the operation which decrypts and re-encrypts a media program encrypted by a pairing key in order to pair a conditional access module and an IRD operationally.</figref><figref num="11">An explanatory diagram showing an operation that can be performed to store a pay-per-view media program that has not been purchased for later purchase and observation.</figref><figref num="12">An explanatory diagram showing an operation performed to play a pay-per-view media program that has not been stored and purchased.</figref><figref num="13">Explanatory diagram showing the operation used to purchase or obtain the right to purchase digital media.</figref><figref num="14">Explanatory diagram illustrating how the selected IRD receives an encrypted data object that has not been purchased for storage and subsequent retrieval.</figref><figref num="15">An explanatory diagram showing the behavior used to purchase and read an unpurchased data object.</figref><figref num="16">Explanatory diagram illustrating the operation used to receive, store, and play low value digital media.</figref>