MXPA00006746A - System and method for copy protection for digital signals - Google Patents

Abstract

Embodiments of the present invention provide for the copy protection of distributed material after conditional access is applied, regardless of where the material is distributed. The solutions described provide the advantage of being sufficiently simple in implementation to qualify as"curb high"solutions."Curb high"solutions provide a range of security from minimal security to a high level of security while requiring relatively fewer system resources to implement than prior approaches.Embodiments of the present invention provide for the copy protection of distributed material after conditional access is applied, regardless of where the material is distributed. The solutions described provide the advantage of being sufficiently simple in implementation to qualify as"curb high"solutions."Curb high"solutions provide a range of security from minimal security to a high level of security while requiring relatively fewer system resources to implement than prior approaches.

Description

SYSTEM AND METHOD FOR COPY PROTECTION FOR / DIGITAL SIGNALS Technical Field of the Invention The present invention relates to copy protection for consumer electronic means and more particularly, to methods and configurations for providing copy protection to audiovisual signals used in consumer electronics.

Background in Art The proliferation of digital technology in consumer electronics has provided a plethora of digital consumer technology products that provide superior performance relative to their analog predecessors. However, the distribution of audiovisual information in digital format, coupled with the availability of digital recording devices, raises concerns about the piracy of digital audiovisual products, particularly in the entertainment industry. In response to this concern, the MPPA (Moti on Pi cture Association of REF .: 121456 America) has proposed films with copy protection distributed in Digital Video Disc (DVD) to prevent a buyer, buy a single copy and distribute multiple copies. However, these concerns are not limited to only audiovisual information distributed on DVD. There is a similar concern for other types of media, for example, cable television and broadcast television among others. Cable television distributors are concerned about protecting their transmissions. One approach has been the use of conditional access to control the distribution of its transmission. Conditional access refers to controlling the distribution of information in user locations. An important difference between using conditional access and copy protection to control the distribution of material is that conditional access is applied to particular distribution sites or nodes, while copy protection continues over distribution sites or nodes. Another approach to protect audiovisual information has been to encrypt the audiovisual signal and add the capacity of receivers to decrypt the audiovisual signal. A problem with this approach is that receivers often require a complex functionality to effect decryption, for example, in the case of public / private key encryption / decryption. Another proposal for media copy protection has been provided by the subcommittee of the data transmission discussion group (DTDG), the CTPWG (Copy Protection Working Group) for copy protection of the Technology of Section 1394. Section 1394 technology refers to the 100 Mbit / s or 400 Mbit / s bus protocol, applicable to consumer electronics. Another proposal is being developed by the NRSSC (Na ti onal Renewable Securi and Standars Commi tee), number of an interim safety standard (IS679) of the EIA (Electronics Industry Associates) that defines two interfaces for the access safety of removable condition. This includes what you have referred to as a "smart card" and a PCMCIA card. Fig. 1 illustrates a conventional configuration 100 to protect copies of an audiovisual signal, using a replaceable security module that is coupled to a receiver, through an IS679 interface. One or more audiovisual signals, identified as AVSi, AVS2, up to AVSN, are provided to a transmitter 102, typically at speeds within the range of 6 Mbit / s to 100 Mbit / s. Audiovisual signals AVSi, AVS2, up to AVSN are encoded by means of encoders Ei, E2, up to EN respectively, using for example, MPEG coding techniques and separated into audio signals ASi, AS2, up to ASN and VSi video signals, VS2, up to VSN. The audio signals ASi, AS2, up to ASN and the video signals VSi, VS2, VSN are then encrypted by the scramblers Sihis.

, S2, up to SN respectively, using for example, any number of encryption techniques per key, widely available. The audio signals ASi, AS2, up to ASN and video signals VSi, VS2, to VSN already encrypted are then combined by means of a combiner 104, into a single audiovisual signal. The combiner 104 may include several processes, such as multiplexers and other processors necessary to provide the unique audio signal. The single audiovisual signal is then provided to a receiver 106 through a link 108. The link 108 can include one or more media and / or communication systems and support devices that are configured to carry the unique audio signal between the transmitter 102 and receiver 106. Examples of link 108 may include, but are not limited to, a telephone system, a cable television system, a television broadcasting system (direct or indirect), a satellite broadcasting system (direct or indirect) , one or more computers and / or computer networks, the Internet, an intranet and any software, physical equipment or any other communication system and equipment associated therewith for transmitting coded data between two locations. After receiving the unique audiovisual signal, the receiver 106 transmits the audio signal to a replaceable security module 110 through an interface 112. For applications in IS679, the replaceable security module 110 is an intelligent card or a PCMCIA card. which will be communicatively coupled to the receiver 106 through an IS679 compatible interface. However, other types of interfaces can be used to couple the replaceable security module 110 to the receiver 106. The replaceable security module 110 includes a descrambler 114 that removes the encryption placed on the audio signals ASX, AS2, up to ASN and the video signals VSi, VS2, up to VSN encoded by means of the scramblers Si, S2, up to SN. The unique descrambled audiovisual signal is then returned to the receiver 106 and decoded with a decoder 116, contained within the receiver 106. The descrambled and decoded audio signal is then provided to a screen 118, so that it is displayed or viewed in any way. One of the advantages of using this approach is that all desalination operations are performed in the replaceable security module 110. This allows manufacturers to provide standard receivers, without the ^ Need for specialized descrambling. In IS679 applications, replaceable security modules can be in the form of a smart card or a PCMCIA card that provides "personalized" security. Despite the advantages of this approach, it does not lack its own disadvantages and limitations. A disadvantage of this approach exists in situations where the interface 112 is accessible, the audiovisual descrambling signals can be redistributed to other locations and then decoded and deployed, bypassing the copy protection. For example, in the case of a DVD player that uses a replaceable security module as illustrated in Fig. 1, if the 112 interface can be accessed, then the descrambled audiovisual signal (unprotected) can be distributed to multiple receivers and screen devices and even more, recorded and distributed again. Based on the need to provide copy protection for audiovisual signals in IS679 applications and the limitations of the above approaches, an approach to provide copy protection of audiovisual signals in IS679 applications, which avoids the problems associated with the above approaches, is highly desirable. .

Description of the invention In general, the embodiments of the present invention provide copy protection of distributed material after conditional access is applied, regardless of where the material is distributed. The solutions described here provide the advantage of being simple enough in their implementation, as to qualify what is known in the art as "high brake" solutions. The "high brake" solutions provide a range of security from minimum security and up to a high level of security, while requiring relatively less system resources to be implemented, compared to previous approaches. The method of the preferred embodiment of the present invention for the protection of audiovisual information copy representing a digital signal, comprises the steps of: (a) encoding the digital signal to obtain a coded signal; (b) converting the encoded signal into a copy protected signal, using a copy protection function, wherein the function uses a data signal representing the copy protection data; and (c) scrambling the protected copy signal to obtain a randomized signal. The system of the preferred embodiment of the present invention for recovering an audiovisual signal from a digital signal including a scrambled signal and a data signal ~~ of copy protection representing the copy protection data comprises a receiver and a descrambler module, connected to each other through a link.

The descrambler module includes: (1) a first communication interface to communicate with the receiver through the link; and (2) a descrambler to descramble an incoming scrambled signal from the receiver through the link.

The receiver includes: (1) a second communication interface for communicating with the descrambler module through the link, (2) a processor for: (i) removing the data signal from the digital signal and storing the copy protection data represented by the data signal in a memory device, (ii) extracting said scrambled signal from the digital signal and providing the scrambled signal to the scrambler through the link, and (3) a retractor to convert a protected copy signal. incoming from the scrambler, back to the audio-visual signal, using a reverse copy protection function, wherein the inverse function uses said stored copy protection data.In this preferred embodiment of the present invention, the signals that flow from the descrambler module towards the receiver through the link, are protected against copy.

Brief Description of the Drawings The foregoing and other features, organizations, advantages and objectives of the present invention, which are considered to be novel, are established as a feature in the appended claims. The present invention, both in its organization, and its mode of operation, together with the additional objects and advantages, will be fully understood from the following detailed description and the attached drawings. Each of the drawings contained herein, are not considered as accurate illustrations, but are provided for illustration purposes only and should be interpreted in conjunction with the attached specification. Fig. 1 illustrates a conventional configuration for protecting an audiovisual signal from copying, using a replaceable security module that is coupled to a receiver through an IS679 interface. Fig. 2 illustrates a configuration for protecting audio-visual signals from copying, using a replaceable security module for a preferred embodiment of the present invention. Fig. 3 is a block diagram of a configuration illustrating a second preferred embodiment of the present invention. Fig. 4 is a block diagram illustrating a computer system on which a preferred embodiment of the invention can be implemented.

Best Way to Carry Out the Invention The following description is provided to enable any person skilled in the art to make and use the invention and thus establish the best modes currently contemplated by the inventors to carry out the invention. However, various modifications will remain apparent to those skilled in the art, since the generic principles of the present invention have been defined herein. Fig. 2 illustrates a configuration 200 for protecting audio-visual signals from copying, using a replaceable security module according to a preferred embodiment of the present invention. Audiovisual signals, identified as AVSi, AVS2, up to AVSN are provided to a transmitter 202, typically at speeds in the range of 6 Mbit / s to 100 Mbit / s. The audiovisual signals AVSi, AVS2, up to AVSN are encoded by means of the encoders Ei, E2 / up to EN respectively, contained within the transmitter 202, using for example, MPEG coding techniques and separating them into audio signals ASi, AS2, up to ASN and video signals VSi, VS2, up to VSN.

A function is applied to audio signals ASi, AS2, to ASN and to video signals VSi, VS2, to VSN via function modules Fi, F2, to FN respectively, to add copy protection. The data of copy protection DATA CP is provided to the transmitter 202 and used by the function modules Fi, F2, to FN to apply the function to the audio signals ASi, AS2, to ASN and to the video signals VSi, VS2, until VSN. After having been processed by function modules Fi, F2, up to FN, audio signals ASi, AS2, up to ASN and video signals VSi, VS2, up to VSN are encrypted by means of scramblers Si, S2, up SN respectively, using for example, any number of widely available encryption techniques and data protection copy data CP. The encryption information required by the scramblers Si, S2, up to SN such as, for example, key encryption information, are provided by means of a conditional access management system (not illustrated) that is typically included within the transmitter 202, but that can reside anywhere else. The audio signals ASX, AS2, up to ASN and the video signals VSi, VS2, to VSN already encrypted, as well as the copy protection data DATA CP are then combined by means of a combiner 204 to provide a single unique audiovisual signal . So that, the data of copy protection CP DATA are included in the unique audiovisual signal. The combiner 204 may include several processors, such as multiplexers and other processors, necessary to provide the unique audio signal. The unique audiovisual signal is then provided to a receiver 206 through the link 208. As well as the link 108 of FIG. 1, the link 208 may include one or more communication means or systems, or both and thus, support apparatuses that are configured to convey the unique audiovisual signal between the transmitter 202 and the receiver 206. Examples of the link 208 include, but are not limited to, a telephone system, a cable television system, a television broadcasting system (direct or indirect), a satellite broadcasting system (direct or indirect), or one or more networks and / or computer buses, the Internet, an intranet, and any software, physical equipment and any other communication system and equipment associated with it same, to transmit encoded data between two locations.

When the receiver 206 receives the audio signal through the link 208, the data of copy protection DATA CP is removed from the audiovisual signal by means of the processor 210. In applications where the audio signal going over the link 208 is formatted in packets, the processor 210 extracts one or more data packets containing the copy data of the CP DATA from the audiovisual signal and replaces them with the data packets containing the predetermined data, such as the NULL values. For example, data packets containing the data of copy protection DATA CP can have a predetermined data packet identification, in such a way that they can be easily identified by processor 210. Then, the audiovisual signal is provided to the module of replaceable security 212 through interface 214. In IS679 applications, the replaceable security module 212 is a smart card or a PCMCIA card which is coupled in communication to the receiver 206 through an interface 214 compatible with IS679. The replaceable security module 212 includes a descrambler 216 that removes the encryption placed on the audio signals ASX, AS2, up to ASN and the video signals VSi, VS2, up to VSN encoded by the scramblers S, S2, up to SN. The single descrambled audiovisual signal is then returned to the receiver 206 through the interface 214. Accordingly, the descrambled audiovisual signal, received by the receiver 206 from the replaceable security module 212, does not contain the encryption provided by the scramblers Si, S2, up to SN, but still does not contain the copy protection applied by the function modules Fi, F2, to FN- The descrambled audio signal is then provided to a function block F_1 that applies an inverse function to F "1 to remove the protection of copy applied by means of the function modules Fi, F2, to FN, using the data of copy protection CP DATA that were extracted from the audiovisual signal by means of the processor 210. In accordance with the preferred embodiment of the present invention, the function block F "1 bases the application of the inverse function F_1 to the descrambled audiovisual signal, in the presence of data packets coughs that contain the default value. For example when function block F "1 which identifies a data packet containing the predetermined value, the new data of copy protection CP DATA retained by the receiver 206 are used by means of the function block F_1, to apply the inverse function F "1 to the subsequent data packets, until the next data packet containing the default value is identified. The descrambled audiovisual signal is then decoded by means of a decoder 218 contained within the receiver 106. The descrambled and decoded audiovisual signal is then provided to a screen 220, to be displayed or viewed in any way. This approach to the preferred embodiment of the present invention provides several important advantages over the above approaches, to provide copy protection to an audio signal. First, this approach provides a higher level of security than the prior art approach described with reference to Fig. 1, since the descrambled signal provided by the replaceable security module 212, contains the copy protection provided by the modules of function Fi, F2, up to FN, but does not contain the data of copy protection CP DATA that was removed by the processor 210. Once already removed from the audio-visual signal, the data of copy protection DATA CP are maintained internally inside the receiver 206. Accordingly, the descrambled signal provided by the replaceable security module 212 can not be used by other receivers and / or recording devices, even in those that contain a function block equivalent to the function block F-1, since they will not have access to the data of copy protection DATA CP, which can be changed periodically. In addition, this copy protection approach is very flexible and allows receiver manufacturers to continue a standard design without the need for special components or algorithms, since processor 210 and function block F_1 can be implemented as standard components. The copy protection functionality, including at the level of copy protection, is defined by the data of copy protection DATA CP, provided to the transmitter 202. Thus, the function modules Fi, F2, up to FN can perform a relatively function simple, such as an exclusive "OR" logical operation (XOR). The advantage of using a simple function is that relatively fewer system resources are required when implementing functions F and F "1, when compared to conventional approaches that use sophisticated encryption algorithms, however, more exotic functions can be used, depending on of the desired copy protection level for a particular application In the context of MPEG2 coding, a single packet of 184 bytes of data can be used to perform an XOR function from 64 to 1000 bits. CP copy data can be changed as frequently as needed, based on the requirements of a particular application In accordance with a second preferred embodiment of the present invention, data protection copy CP DATA is not included in the audiovisual signal , instead they are generated internally by the receiver and provided to a replaceable security module e Fig. 3 is a block diagram of a configuration 300 illustrating this approach. A receiver 302 receives an audiovisual signal (AVS) which is provided to a replaceable security module 304 through the interface IS679 306. The replaceable security module includes a descrambler 308 for descrambling the audio-visual signal. The audiovisual signal is then provided to a function module F that protects the audiovisual signal from copying by applying a function to the audiovisual signal, using copy protection data to generate a processed audiovisual signal. The data of copy protection DATA CP are generated randomly by means of the receiver 302 and provided to the replaceable security module 304. The processed audiovisual signal is provided back to the receiver 302 through the interface 306, where the function module applies a function using the data protection data COP DATA, to remove the copy protection previously applied by the function module F. The data of the audiovisual signal is then decoded by means of a decoder D and provided to the screen 310 to be deployed or seen in any way. This approach avoids having to include data protection copy CP DATA in the audiovisual signal. Since the data of copy protection DATA CP can be generated randomly, the use of specialized components or algorithms within the receiver 302 is thus avoided. Although the embodiments of the invention have been described here, in the context of providing protection copy for an IS679 interface application, the approaches described here are applicable to other audiovisual configurations. In addition, the approaches described here are applicable to other types of signals and information, in addition to audiovisual signals. The various components described above can be implemented as discrete hardware components, one or more software processes, or a combination of hardware components and one or more software processes. In this regard, Fig. 4 is a block diagram illustrating a computer system 400 over which, one embodiment of the invention can be implemented. The computer system 400 includes a bus 402 or another communication mechanism for communicating information, and a processor 404 coupled with the bus 402 to process information. The computer system 400 also includes a main memory 406, such as a random access memory (RAM) or other dynamic storage device, coupled to the bus 402 for storing instruction information, to be executed by means of the processor 404. The main memory 406 may also be used to store temporary variables or other intermediate information during instruction execution, to be executed by processor 404. Computer system 400 additionally includes a read-only memory (ROM) 408 or other device static storage coupled to the bus 402 for storing static information and instructions for the processor 404. A storage device 410, such as a magnetic disk or optical disk, is provided and coupled to the bus 402 for storing information and instructions. Computer system 400 may be coupled through bus 402, to a screen 412, such as a cathode ray tube (CRT) screen, to display information to a user of the computer. An input device 414, including alphanumeric keys and other keys, is coupled to the bus 402 to communicate information and command selections for the processor 404. Another type of user input device is a cursor control 416, such as a mouse, a tra ckball, or cursor direction keys to communicate the address information and command selections to the processor 404 and to control the movement of the cursor on the screen 412. This input device typically has two degrees of freedom on two axes , a first axis (for example, x) and a second axis (for example, y), that allow the device to specify positions within a plane.

The embodiments of the present invention are related to the use of computer systems 400 to provide copy protection of audiovisual signals in IS679 applications. According to a preferred embodiment of the invention, the protection of copying of audiovisual signals in IS679 applications is provided by means of a computer system 400, in response to the processor 404 executing one or more sequences of one or more instructions contained within of the memory 406. Said instructions can be read in the main memory 406 from another computer-readable medium, such as a storage device 410. The execution of the instruction sequences contained within the main memory 406, cause the processor 404 perform the process steps described here. One or more processors within a multiprocessor configuration may also be employed to execute the instruction sequences contained within the main memory 406. In alternative embodiments, wired circuits may be used instead of, or in combination with, software instructions to implement the embodiments of the present invention. Accordingly, the embodiments of the present invention are not limited to any specific combination of hardware or software circuits. The term "computer-readable medium", as used herein, refers to any means that participates in providing instructions to the 404 processor for execution. Said means can take various forms, including but not limited to, non-volatile media, volatile media and transmission media. Non-volatile means include, for example, optical or magnetic disks, such as storage device 410. Volatile means include dynamic memory, such as main memory 406. Transmission media include coaxial cables, copper cables and optical fiber, including the cables comprising bus 402. The transmission means may also take the form of light or acoustic waves, such as those generated during infrared data or radio wave communications. Common forms of computer readable media include, for example, a floppy disk, a floppy disk, a hard disk, a magnetic tape or any other magnetic media, a CD-ROM, any other optical media, pressure cards, tape of paper, any other physical medium with patterns or holes, a RAM memory, a PROM memory and EPROM memory, a FLASH-EPROM memory, any other chip or memory cartridge, a transport wave as will be described later, or any other medium from which you can read a computer. Various forms of computer readable media may be involved in transporting one or more sequences of one or more instructions to the 404 processor for execution. For example, the instructions can be transported initially on a magnetic disk of a remote computer. The remote computer can load the instructions into its dynamic memory and send them over a telephone line using a modem. A local modem to the computer system 400 can receive the data over the telephone line and use an infrared transmitter to convert the data to an infrared signal. The infrared detector coupled to the bus 402 can receive the data carried in the infrared signal and place it on the bus 402. The bus 402 transports the data to the main memory 406, from which the processor 404 removes and executes the instructions. The instructions received by the main memory 406 can optionally be stored on the storage device 410, either before or after execution by the processor 404. The computer system 400 also includes a communication interface 418 coupled to the bus 402 The 418 communication interface provides two-way data communication, by coupling to a network link 420 that is connected to a local network 422. For example, the communication interface 418 may be in an Integrated Services Digital Network (ISDN) card or a modem, to provide a communication connection for a corresponding type of telephone line. As another example, the communication interface 418 may be a local area network (LAN) card to provide a communication connection for a compatible local area network. Wireless links can also be implemented. In any such implementation, the communication interface 418 sends and receives electrical, electromagnetic or optical signals that carry digital data frames representing various types of information. Network link 420 typically provides data communication through one or more networks for other data devices. For example, the network link 420 may provide a connection through the local network 422 to a host computer 424 or to a data equipment operated by an Internet Service Provider (ISP) 426. In turn, the ISP provides data communication services through the global packet data communication network, now commonly referred to as the "Internet" 428. The local network 422 and the Internet 428 use both electrical, electromagnetic or optical signals that transport data frames digital The signals that pass through the various networks and the signals that go over the network link 420 and through the communication interface 418, which transports the digital data to and from the computer systems 400, are exemplary forms of transporter waves , that transport information. The computer system 400 can send messages and receive data, including programming codes, through the network (s), the network link 420 and the communication interface 418. In the example of the Internet, a server 430 can transmit a required code for a program application via the Internet 428, the ISP 426 the local network 422 and the communication interface 418. According to the invention, a downloaded or downloaded application provides the copy protection of audiovisual signals in IS679 applications, as described here. The received code may be executed by means of the processor 404 as long as it is received, and / or stored in the storage device 410, or in another non-volatile storage device for later execution. In this respect, the computer systems 400 can obtain the application code in the form of a conveyor wave. In the above specification, the invention has been described with reference to the specific embodiments thereof. However, it should be evident that various modifications and changes may be made to it, without departing from the broader essence and scope of the invention. The specification and the drawings are, accordingly, referred in an illustrative rather than respective manner.

Industrial Applicability The copy protection for digital signals according to the present invention can be applied to the field of audiovisual information recording, in connection with audiovisual information distributed on DVD and other media such as cable television, television broadcasting and the Internet. , to effectively protect a buyer from buying a single copy and making and distributing multiple copies.

It is noted that, with regard to this date, the best method known by the requested, to carry out the present invention, is that which is clear from the present, discovering the invention. Having described the invention as above, the content of the following is claimed as property.

Claims (17)

1. CLAIMS A method for protecting a digital signal representing an audiovisual information from copying, characterized in that it comprises the steps of: (a) encode the digital signal to obtain a coded signal; (b) convert the encoded signal into a signal Copy protected, using a copy protection function, wherein the function uses a data signal representing the copy protection data; Y 15 (c) randomize the protected copy signal to obtain a randomized signal.
2. The method according to claim 1, characterized in that it additionally comprises the step of transmitting a randomized signal and 20 the data signal to a receiver.
3. The method according to claim 1, characterized in that it additionally comprises the step of transmitting the scrambled signal and the data signal in the form of a single signal.
4. The method according to claim 3, characterized in that the step of transmitting further comprises combining the scrambled signal and the data signal in a single single signal.
5. The method according to claim 3, characterized in that it additionally comprises the steps of: (a) receive the unique signal in a receiver; (b) removing the copy protection data signal from the single signal, and storing the copy protection data represented by the copy protection data signal, in a memory device; (c) recovering the descrambler signal from the single signal; (d) descrambling and recovering the scrambled signal to recover the protected copy signal; (e) converting the protected copy signal recovered back into the encoded signal, using a reverse copy protection function, wherein the inverse function uses the stored copy protection data; Y (f) decoding the encoded signal to recover the digital signal.
6. The method according to claim 1, characterized in that it additionally comprises the steps of: (a) descrambling the scrambled signal to recover the protected copy signal; (b) reconverting the protected signal from a recovered copy back into the encoded signal, using a reverse copy protection function, wherein the inverse function uses the copy protection data from the data signal; Y (c) decoding the converted encoded signal to recover the digital signal.
7. A method for recovering an audiovisual signal from a digital signal including a descrambled signal and a copy protection data signal represents the copy protection data, characterized in that it comprises the steps of: (a) extracting the data signal from the digital signal; (b) storing the copy protection data from the data signal, in a memory device; (c) extract the randomized signal from the digital signal (d) descrambling the scrambled signal to recover a copy protected signal; (e) converting the protected copy signal into an encoded signal, using a reverse copy protection function, wherein the inverse function uses the stored copy protection data; Y (f) decoding the encoded signal to recover the audiovisual signal.
8. A system for protecting a digital signal representing audiovisual information from copying, characterized in that it comprises: (a) an encoder for encoding the digital signal, in order to obtain an encoded signal; (b) a converter for converting the encoded signal into a copy protected signal, using a copy protection function, wherein the function uses a data signal representing the copy protection data; Y (c) a scrambler to randomize the protected copy signal in a randomized signal.
9. The system according to claim 8, characterized in that it additionally comprises a transmitter for transmitting the randomized signal and the data signal to a receiver.
10. The system according to claim 8, characterized in that it additionally comprises a combiner for combining the scrambled signal and the data signal in a single single signal and a transmitter for transmitting the single signal.
11. The system according to claim 8, characterized in that it additionally comprises a transmitter for transmitting the randomized signal and the data signal in the form of a single single signal.
12. The system according to claim 11, characterized in that it additionally comprises: (a) a receiver to receive the single signal 10 inside a receiver; (b) a processor for: (1) removing the data signal from the single signal and storing the copy protection data represented by the data signal within 15 of a memory device, and (2) recovering the scrambled signal from the single signal; (c) a descrambler to descramble the scrambled signal recovered for 20 recover the protected copy signal; (d) a retractor to convert the recovered copy signal back into the encoded signal, using a reverse copy protection function, wherein the inverse function uses the stored copy protection data; Y (e) a decoder for decoding the encoded signal, in order to recover the digital signal.
13. The system according to claim 8, characterized in that it additionally comprises: (a) a descrambler to descramble the randomized signal, in order to recover the protected copy signal; (b) a retractor to convert the protected copy signal recovered back into an encoded signal, using a reverse copy protection function, wherein the inverse function uses the copy protection data from the data signal; Y (c) a decoder for decoding the converted encoded signal, in order to recover the digital signal.
14. A system for recovering an audiovisual signal from a digital signal includes a scrambled signal and a copy protection data signal representing the copy protection data, characterized in that the system comprises: (a) a processor for: (1) removing the data signal from the single signal and storing the copy protection data represented by the data signal within a memory device, and (2) recovering the signal randomized from the digital signal; (b) a descrambler to descramble the scrambled signal recovered to recover the protected copy signal; (c) a retractor to convert the protected copy signal recovered back into the encoded signal, using a reverse copy protection function, wherein the inverse function uses the stored copy protection data; Y (d) a decoder to decode the encoded signal, in order to recover the audiovisual signal.
15. A system for recovering an audiovisual signal from a digital signal including a randomized signal and a copy protection data signal representing the copy protection data, characterized in that the system comprises a receiver and a descrambler module connected to each other through a link, where: (a) the descrambler module includes: (1) a first communication interface to communicate with the receiver through the link, and (2) a descrambler to descramble a randomized signal incoming from the receiver through the link; Y (b) the receiver includes: (1) a second communication interface to communicate with the descrambler module through the link, (2) a processor for: (i) removing the data signal from the digital signal and storing the copy protection data represented by the data signal within a memory device, and (ii) recovering the randomized signal from the single signal, and (3) a retractor to convert the protected copy signal from the descrambler back into the audio-visual signal, using a reverse copy protection function, wherein the inverse function uses the stored copy protection data; and wherein the signals flowing from the descrambler module to the receiver, through the link, are protected against copying.
16. 16. The system according to claim 15, characterized in that the audiovisual signal 15 which is inside the receiver, is coded and scrambled, and wherein the receiver additionally includes a decoder to decode the converted signal.
17. 17 The system in accordance with the claim 20 15, characterized in that the descrambler module comprises a PCMCIA card. The system according to claim 15, characterized in that the first and second communication interfaces comprise interfaces compatible with IS679. The system according to claim 15, characterized in that the link comprises one or more communication means configured to convey audiovisual signals. A method for copying protection signals that flow from a descrambler module to a receiver through a link, in a copy protection system that includes the receiver interconnected to the descrambler module through the link, characterized in that it comprises the steps of: (a) receiving a digital signal in the receiver, the digital signal including an audio signal descrambled; (b) generating a copy protection data signal representing the copy protection data; (c) transmitting the digital signal from the receiver to the descrambler module through the link; (d) descrambling the randomized audiovisual signal in the module - descrambler, in order to obtain the audiovisual signal; (e) converting the audio signal in the descrambler module into a copy protected signal, using a copy protection function, wherein the function uses the data signal; (f) transmitting the protected copy signal from the descrambler to the receiver through the link; Y (g) converting the protected copy signal to the audio signal on the receiver using a reverse copy protection function, where the inverse function uses the data signal. The method in accordance with the claim 20, characterized in that the step of generating the data signal includes generating the copy protection data signal within the receiver. The method in accordance with the claim 21, characterized in that it additionally comprises the step of transmitting the data signal from the receiver to the descrambler module through the link. The method according to claim 20, characterized in that the audio signal in step (a) is coded and scrambled. The method according to claim 23, characterized in that it additionally comprises the step of decoding the audiovisual signal within the receiver, after the conversion step. The method according to claim 20, characterized in that the descrambler module comprises a PCMCIA card. The method according to claim 20, characterized in that the link comprises one or more communication means configured to carry audiovisual signals. The method according to claim 20, characterized in that the receiver and the descrambler module use interfaces compatible with IS679 for their communication through the link. A copy protection system comprising a receiver and a descrambler module, connected to each other through a link, characterized in that: (a) the descrambler module includes: (1) a first communication interface to communicate with the receiver through the link, (2) a descrambler to descramble a randomized audio signal incoming from the receiver through the link, and (3) a converter for converting the audio signal into a copy protected signal, using a copy protection function, the function using the copy protection data from the receiver and to provide the protected copy signal to the receiver through the link; (b) the receiver includes: (1) a second communication interface for communicating with the descrambler module through the link, (2) a signal generator for generating a copy protection data signal representing the protection data. of copying and providing said data to the descrambler through the link, and (3) a retractor to convert an incoming copy protected signal from the descrambler back into an audiovisual signal, using a reverse copy protection function, wherein the function Inverse uses said copy protection data; wherein, in response to receiving a digital signal that includes a randomized audiovisual signal, the receiver transmits the digital signal and the copy protection data to the descrambler module through the link, and where, in response to receiving the signal digital and copy protection data from the receiver, the descrambler module descrambles and converts the audio signal into a copy-protected signal and transmits the protected copy signal to the receiver through the link, so the signals that flow from the descrambler module towards the receiver through the link, are protected against copies. The system according to claim 28, characterized in that the audio signal coming into the receiver is coded and scrambled and wherein the receiver additionally includes a decoder to decode the converted signal. The system according to claim 28, characterized in that the descrambler module comprises a PCMCIA card. The system according to claim 28, characterized in that the first and second communication interfaces comprise interfaces compatible with IS679. The system according to claim 28, characterized in that the link comprises one or more communication means configured to carry audiovisual signals.