Illegal view/copy protection method and apparatus for digital broadcasting system

• US 5,799,081 A
• Filed: 10/27/1995
• Issued: 08/25/1998
• Est. Priority Date: 09/18/1995
• Status: Expired due to Term

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Park, Tae Joon, Kim, Yung Gil
• Primary Examiner(s): CANGIALOSI, SALVATORE A
• Application Number:
  US08/549,421
• Time in Patent Office: 1,033 Days
• Field of Search: 380/3-5, 380/20
• US Class Current: 380/203
• CPC Class Codes: H04N 2005/91328 the copy protection signal being a copy management signal, e.g. a copy generation management signal [CGMS]
• CPC Class Codes: H04N 2005/91364 the video signal being scrambled
• CPC Class Codes: H04N 21/2541 Rights Management protecting software against unauthorised usage in a vending or licensing environment G06F21/10; security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08
• CPC Class Codes: H04N 21/4408 involving video stream encryption, e.g. re-encrypting a decrypted video stream for redistribution in a home network
• CPC Class Codes: H04N 21/835 Generation of protective data, e.g. certificates protecting software against unauthorised usage in a vending or licensing environment G06F21/10
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection
• CPC Class Codes: H04N 7/163 by receiver means only
• CPC Class Codes: H04N 7/1675 Providing digital key or authorisation information for generation or regeneration of the scrambling sequence pseudo-random number generators in general G06F7/58

Abstract

An illegal view/copy protection method for a digital broadcasting system is disclosed including an audio/video signal transmission step for multiplexing and transmitting audio/video bit stream scrambled in control words and information where the control words and CPTC information for illegal view/copy protection are encrypted; and an audio/video reception step for decrypting the transmitted bit stream to analyze the CPTC information and control words, deciding whether recording is allowed or not to be recorded on cassette tape, and using the control words, performing descrambling and decoding to output audio/video signals to a monitor, thereby protecting copyright.

Claims

1. An illegal view/copy protection method for a digital broadcasting system comprising:

an audio/video signal transmission step for multiplexing and transmitting an audio/video bit stream scrambled in control words and information where the control words and Copy Protection Transmission Code (CPTC) information for illegal view/copy protection are encrypted; and

an audio/video reception step for decrypting the transmitted bit stream to analyze the CPTC information and control words, deciding whether recording is allowed or not to be recorded on digital signal storing media, and using the control words, performing descrambling and decoding to output audio/video signals to a monitor.

2. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 1, wherein said CPTC information is formatted in a generational copy control field for limiting the number of copies available, and a reproducibility control field for limiting a reproduction of a copied program.

3. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 2, wherein said CPTC information is formatted further containing a descrambling information field where part of the control words for descrambling are recorded.

4. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 2, wherein said CPTC information is formatted to further include a Conditional Access (CA) field where CA information for conditional access is recorded.

5. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 2, wherein said generational copy control field is made up of a permissible generational field for limiting the number of copy permissible and a present generational field for indicating the present generation of a program copied.

6. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 2, wherein said reproduction control field is made up of a reproducible number field for limiting the number of reproducing a copied program, and a maximum reproducible time field for limiting time to reproduce the copied program.

7. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 1, wherein the data recorded on the digital signal storing media contains scrambled audio/video bit stream and CPTC information.

8. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 7, wherein said CPTC information is overwritten on the scrambled audio/video bit stream for error effect and recorded on the digital signal storing media.

9. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 7, wherein said CPTC information is recorded on a portion of the audio track of the digital signal storing media.

10. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 7, wherein said CPTC information is recorded on a portion of the control track of the digital signal storing media.

11. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 7, wherein said CPTC information is recorded on a portion of the video track of the digital signal storing media.

12. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 1, wherein said audio/video signal transmission step comprises the steps of:

encoding the audio/video bit stream;

generating a control word for scrambling;

scrambling for the encoded audio/video bit stream using the generated control word;

generating CPTC information for illegal view/copy protection;

encrypting for encrypting the control word and CPTC information; and

multiplexing and transmitting the scrambled audio/video bit stream and encrypted CPTC information.

13. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 1, wherein said audio/video signal transmission step comprises the steps of:

encoding the audio/video bit stream;

generating a control word for scrambling;

scrambling for the encoded audio/video bit stream using the generated control word;

generating CPTC information for illegal view/copy protection;

generating conditional access information for conditional reception;

encrypting for encrypting the CPTC information and CA information; and

multiplexing and transmitting the scrambled audio/video bit stream and encrypted CPTC information and conditional access information.

14. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 1, wherein said audio/video reception step comprises the steps of:

filtering the transmitted bit stream and decrypting the CPTC information;

analyzing the CPTC information to generate a control word and a signal for controlling the protection of copyright and to update the CPTC information;

deciding whether to allow recording according to the signal for controlling the protection of copyright to record the scrambled and transmitted bit stream on the digital signal storing media; and

descrambling and decoding the transmitted bit stream in the control word and outputting an audio/video signal.

15. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 14, wherein said all of the control word is contained in the CPTC information.

16. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 14, wherein said CPTC information analyzing step comprises the steps of:

generating a control word;

detecting a permissible generation of a permissible generational field for limiting the available number of copy of a program of the CPTC information and the present generation of the present generational field indicating the present generation of the program copied, to thereby perform copy-impossible and update the CPTC information; and

detecting the reproducible number of the reproducible number field for limiting the number of reproduction of copied programs of the CPTC information, the maximum reproducible time of the maximum reproducible time field for limiting time to reproduce the copied program, and the number and time of reproduction of tape, to thereby process reproduction-impossible.

17. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 14, wherein said copying number limiting step comprises the steps of:

comparing the permissible generation of the permissible generational field and the present generation of the present generational field and deciding whether the permissible generation is below the present generation;

if the permissible generation is below the present generation, generating an output disable signal to make copying impossible and destroying the control word; and

if the permissible generation is not below the present generation, increasing the present generation by `1` and recording the result on the digital signal storing media.

18. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 17, wherein said copying number limiting step further comprises the step of, if the permissible generation is not below the present generation, updating the CPTC information.

19. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 17, wherein said reproduction limiting step comprises the steps of:

comparing the reproducible number of the reproducible number field and the reproduction number of tape and deciding whether the reproducible number is below the reproduction number of tape;

if the reproducible number is not below the reproduction number of tape, comparing the maximum reproducible time and reproduction time of tape, and deciding whether the maximum reproducible time is below the reproduction time of tape;

if the maximum reproducible time is not below reproduction time of tape, turning off an enable erase signal to thereby enable the copied program to be reproduced; and

if the reproducible number is below the reproduction number of tape or the maximum reproducible time is below the reproduction time of tape, turning on the enable erase signal to make the reproduction of the copied program impossible so that part of or the whole program recorded on the digital signal storing media is erased.

20. An illegal view/copy protection method for a digital broadcasting system as claimed in claim 13, wherein said audio/video reception step comprises the steps of:

filtering the transmitted bit stream and decrypting the CPTC information;

analyzing the CPTC information to generate a control word and a signal for controlling the protection of copyright and to update the CPTC information;

deciding whether to allow recording according to the signal for controlling the protection of copyright to record the scrambled and transmitted bit stream on the digital signal storing media; and

descrambling and decoding the transmitted bit stream in the control word and outputting an audio/video signal.

21. An illegal view/copy protection apparatus for a digital broadcasting system comprising:

a program producing portion for multiplexing information encrypted both with a control word for scrambling and a Copy Protection Transmission Code (CPTC) information for prohibiting illegal view/copy, and the audio/video bit stream scrambled in control words, to thereby make a program;

a distribution medium portion for distributing programs made in said program producing portion through a transmission medium; and

a program receiving portion for detecting and analyzing the CPTC information from the bit stream transmitted from said distribution medium portion and the bit stream reproduced from digital signal storing media, and descrambling and decoding the bit stream transmitted from said distribution medium portion.

22. An illegal view/copy protection apparatus for a digital broadcasting system as claimed in claim 21, wherein said program producing portion comprising:

a control word generator for generating a control word for scrambling;

a CPTC generator for generating the CPTC information for prohibiting illegal view/copy;

a scrambling portion for scrambling the audio/video bit stream using the control word output from said control word generator;

an encrypting portion for encrypting the control word output from said control word generator and the CPTC information output from said CPTC generator; and

an adder for multiplexing the signals output from said scrambling portion and encrypting portion and transmitting them to said distribution medium portion.

23. An illegal view/copy protection apparatus for a digital broadcasting system as claimed in claim 21, wherein said distribution medium portion comprises:

a broadcasting medium for distributing the program made by said program producing portion through cable, satellite or terrestrial broadcasting; and

a recording medium for distributing the program made by said program producing portion through digital signal storing media.

24. An illegal view/copy protection apparatus for a digital broadcasting system as claimed in claim 23, wherein said program receiving portion comprises:

a decrypting portion for decrypting the bit stream transmitted from said broadcasting medium;

a CPTC detecting/analyzing portion for detecting and analyzing the CPTC information from the bit stream output from said decrypting portion and recording medium, and outputting signals for controlling the control word and illegal view/copy;

a descrambling portion for descrambling the bit stream transmitted from said broadcasting medium and recording medium and the bit stream reproduced from the digital signal storing media;

a decoding portion for decoding and displaying the signal output from said descrambling portion; and

a recording/reproducing portion for recording the bit stream transmitted from said broadcasting medium and recording medium according to the signal output from said CPTC detecting/analyzing portion, and reproducing the digital signal storing media, to thereby output the result to said descrambling portion and CPTC detecting/analyzing portion.

25. An illegal view/copy protection apparatus for a digital broadcasting system as claimed in claim 21, wherein said CPTC information is formatted in a generational copy control field for limiting the number of copies available, and a reproducibility control field for limiting a reproduction of a copied program.

26. An illegal view/copy protection apparatus for a digital broadcasting system as claimed in claim 25, wherein said reproduction control field is made up of a reproducible number field for limiting the number of reproducing a copied program, and a maximum reproducible time field for limiting time to reproduce the copied program.

27. An illegal view/copy protection apparatus for a digital broadcasting system as claimed in claim 21, wherein said program receiving portion comprises:

an Integrated Receiver/Decoder (IRD) for receiving, decoding and descrambling the bit stream transmitted from said broadcasting medium, outputting analog audio/video data to be displayed and outputting scrambled digital audio/video data to be recorded on digital signal storing media; and

a smart card for decrypting the bit stream output from said IRD, detecting/analyzing the CPTC information, and outputting the control word and signals for controlling illegal view/copy to said IRD in order to perform conditional access and copy protection.

28. An illegal view/copy protection apparatus for a digital broadcasting system as claimed in claim 27, wherein said program receiving portion further comprises a Digital Video Cassette Recorder (DVCR) for recording the digital audio/video data and CPTC information scrambled and output from said IRD on the digital signal storing media, and reproducing the scrambled digital audio/video data and CPTC information recorded on the digital signal storing media to be output to said IRD.

29. An illegal view/copy protection apparatus for a digital broadcasting system as claimed in claim 28, wherein said smart card comprises:

an Entitlement Control Message (ECM) filter for filtering the ECM from the bit stream output from said IRD;

a CPTC/tape state signal filter for filtering the CPTC information and the tape state signal indicative of the state of tape from the bit stream output from said IRD;

an Entitlement Management Message (EMM) filter for filtering the EMM containing the EMM from the bit stream output from said IRD;

a lookup table for, in case that the EMM is updated for copyright protection by a broadcasting station, storing the previous EMM containing information required to decode the CPTC information, and outputting CPTC information corresponding in reproduction in order to continuously reproduce the program of digital signal storing media copied;

an EMM processing portion for processing the EMM using the EMM output from said EMM filter and lookup table and the tape state signal output from said state signal filter;

a CPTC processing portion for processing the CPTC information using the signals output from said CPTC/tape state signal filter and EMM processing portion; and

a Conditional Access (CA) processing portion for outputting control word CW using the signals output from said ECM filter and EMM processing portion.

30. An illegal view/copy protection apparatus for a digital broadcasting system as claimed in claim 28, wherein said smart card comprises:

an Entitlement Control Message (ECM) filter for filtering the ECM from the bit stream output from said IRD;

an Entitlement Management Message (EMM) filter for filtering the EMM containing the EMM from the bit stream output from said IRD;

a tape state signal filter for filtering the tape state signal output from said IRD;

a lookup table for, in case that the EMM is updated for copyright protection by a broadcasting station, storing the previous EMM containing information required to decode the CPTC information, and outputting CPTC information corresponding in reproduction in order to continuously reproduce the program of digital signal storing media copied;

an EMM processing portion for processing the EMM using the EMM output from said EMM filter and lookup table and the tape state signal output from said tape state signal filter;

a CPTC processing portion for processing the CPTC information using the signals output from said EMM filter and tape state signal filter, to thereby output ECM, enable erase signal and ID signal; and

a Conditional Access (CA) processing portion for outputting control word CW using the signals output from said ECM filter and EMM processing portion.

31. An illegal view/copy protection apparatus for a digital broadcasting system as claimed in claim 28, wherein said DVCR comprises:

a deck mechanism;

a recording/reproducing portion for recording digital data on digital signal storing media according to said deck mechanism and reproducing the digital data recorded on the digital signal storing media;

a reproduction number detecting/updating portion for detecting/updating the reproduction number from the digital data reproduced from said recording/reproducing portion, and outputting it to said IRD in order to rerecord it in said recording/reproducing portion;

a digital data processing portion for processing the digital data reproduced from said recording/reproducing portion, outputting it to said IRD, and outputting switching position information for recording and reproducing;

a recording/playback switching portion for outputting a switching signal for controlling the reproduction number, the reproduction of digital data and the recording of the updated reproduction number using the switching position information output from said digital data processing portion; and

an error correction encoder/decoder for correcting the error of data output from said digital data processing portion, and encoding and decoding the data to be output to said digital data processing portion.