Method and apparatus for copy protection for various recording media

• US 5,513,260 A
• Filed: 06/29/1994
• Issued: 04/30/1996
• Est. Priority Date: 06/29/1994
• Status: Expired due to Term

• Current Assignee: Macrovision Corporation (Adeia Inc.)
• Original Assignee: Macrovision Corporation (Adeia Inc.)
• Inventors: Ryan, John O.
• Primary Examiner(s): Barron, Jr., Gilberto
• Application Number:
  US08/267,635
• Time in Patent Office: 671 Days
• Field of Search: 380/3, 380/4, 380/5, 380/23, 380/25, 369/44.26, 369/44.33
• US Class Current: 380/200
• CPC Class Codes: G06F 2211/007 Encryption, En-/decode, En-/decipher, En-/decypher, Scramble, (De-)compress
• CPC Class Codes: G06F 7/725 over elliptic curves
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00123 the record carrier being identified by recognising some of its unique characteristics, e.g. a unique defect pattern serving as a physical signature of the record carrier
• CPC Class Codes: G11B 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00246 wherein the key is obtained from a local device, e.g. device key initially stored by the player or by the recorder
• CPC Class Codes: G11B 20/00536 wherein encrypted content data is subjected to a further, iterated encryption, e.g. interwoven encryption
• CPC Class Codes: G11B 20/00586 said format change concerning the physical format of the recording medium
• CPC Class Codes: G11B 20/00695 said measures preventing that data are read from the recording medium
• CPC Class Codes: H04L 2209/605 Copy protection
• CPC Class Codes: H04L 9/0825 using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates
• CPC Class Codes: H04L 9/3247 involving digital signatures
• CPC Class Codes: H04N 2005/91342 the copy protection signal being an authentication signal
• CPC Class Codes: H04N 2005/91364 the video signal being scrambled
• CPC Class Codes: H04N 21/8358 involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection

Abstract

A method and apparatus for copyright protection for various recording media such as compact discs (CDs) uses a combination of symmetrical and asymmetrical data encryption to permit the player to handle either copy-protected or non-copy-protected media, in a manner that is extremely difficult to compromise. Coupled with the combination of encrypting methods, an Authenticating Signature is recorded on the media only when copy-protection is required. The nature of this Authenticating Signature is such that it will not be transferred to illicit copies made on CD recorders. When either an original protected or an original non-protected disk is played, the presence or absence of the Authenticating Signature causes the player to correctly decrypt the program data. All original CDs therefore play normally. When a copy of a non-protected CD is played, the absence of the Authenticating Signature also causes the player to correctly decrypt the program data. However, when a copy of a protected CD is played, the absence of the Authenticating Signature causes the player to generate false data which prohibits the disk from playing normally.

Claims

1. A method of providing copy-protection for a program distribution medium comprising the steps of:

adding an authenticating signature to media to be copy-protected;

passing program data through a first encryptor;

passing said first encrypted program data from said first encryptor through a second encryptor;

recording the data from the second encryptor on a media;

detecting the authenticating signature in a media player;

passing decoded data from said media through a first decryptor;

passing said first decrypted data from said first decryptor through a second decryptor;

selecting an output of said second decryptor when an authenticating signal is detected, and selecting an output of said first decryptor when an authenticating signature is not detected.

2. A method as recited in claim 1 wherein said first encryptor and said second decryptor are complementary.

3. A method as recited in claim 1 wherein said second encryptor and said first decryptor are complementary parts of an asymmetrical or public key encryption system.

4. A method as recited in claim 2 wherein said first encryptor is a device which inverts or interchanges one or more bits of the data block and said second decryptor performs the complementary logical operation.

5. A method for providing copy protection in a mastering process of a recording medium comprising the steps of:

inputting a data stream

generating a first key signal;

coupling said first key signal to a symmetrical encryptor;

coupling said data stream to said symmetrical encryptor

encrypting said data stream;

coupling said symmetrical encryptor to a selector;

coupling said data stream to said selector;

generating a second key signal;

coupling said second key signal to an asymmetrical encryptor;

selecting whether said data stream or symmetrically encrypted data is coupled to said asymmetrical encryptor;

asymmetrically encrypting data selected;

coupling asymmetrical encrypted data to a a data processing portion of a mastering device;

generating an authenticating signature signal; and

coupling said authenticating signature signal to a time base control mechanism of a disc mastering device when symmetrically encrypted data is coupled to said asymmetrical encryptor to modify said time base control mechanism according to said authenticating signature signal.

6. A method as recited in claim 5, wherein said recording medium is an optical compact disc.

7. A method as recited in claim 5, wherein said recording medium is a CD ROM disc.

8. A method as recited in claim 5, wherein said recording medium is a magnetic tape.

9. A method as recited in claim 5, wherein said first key signal is a random key.

10. A method as recited in claim 5, wherein said second key signal is a secret key.

11. A method as recited in claim 5, wherein said data stream is unencrypted.

12. A method for providing copy protection in a playback process of a previously recorded medium which may contain previously encrypted data in a playback device comprising the steps of:

providing previously encrypted data from said previously recorded medium;

generating a first key signal;

coupling said first key signal to an asymmetrical decryptor;

asymmetrically decrypting data from said previously recorded medium, thus producing a first decrypted data stream;

finding a second key signal from a key database;

generating a second key signal;

coupling said second key signal to a symmetrical decryptor;

coupling said first decrypted data stream to said symmetrical decryptor;

symmetrically decrypting said first decrypted data stream, thus producing a second decrypted data stream;

providing a servo signal which may contain an authenticating signal;

detecting a presence of said authenticating signal;

creating a copy protection signal based upon detection of said authenticating signal;

selecting said first decrypted data stream when a copy protection signal is not present;

selecting said second decrypted data stream when said copy protection signal is present; and

outputting selected data to a data processing portion of said playback device.

13. A method as recited in claim 12 wherein said previously recorded medium is a CD ROM disc.

14. A method as recited in claim 12 wherein said previously recorded medium is a compact audio disc.

15. A method as recited in claim 12 wherein said previously recorded medium is a compact audio disc.

16. A copy protection recording apparatus for master recording on a recording medium comprising:

an input terminal for receiving a digital data stream;

a symmetrical encryptor;

a first random key generator to provide a first key signal, said first key signal coupled to said symmetrical encryptor;

an operator controlled switch thereby determines whether said digital data stream or output of said symmetrical encryptor is coupled to an asymmetrical encryptor;

a second key generator to provide a second key signal, said second key signal being coupled to said asymmetrical encryptor;

said asymmetrical encryptor being coupled to a data processing portion of a master recording device;

when said operator controlled switch is in an off position said digital data stream is asymmetrically encrypted by said asymmetrical encryptor;

an authenticating signature generator that generates an authenticating signature signal that indicates that a master recording is to be copy protected and said authenticating signature signal is coupled to a time base signal system; and

wherein said authenticating signature signal is coupled to said time base signal system of said master recording device when said operator controlled switch is placed in an on position.

17. An apparatus as recited in claim 16 wherein said recording medium is a digital audio tape.

18. An apparatus as recited in claim 16 wherein said recording medium is a CD ROM disc.

19. An apparatus as recited in claim 16 wherein said recording medium is a compact audio disc.

20. An apparatus as recited in claim 16 wherein said time base signal system is a radial actuator system and said authenticating signature signal modulates a radial position of said radial actuator system during mastering.

21. An apparatus as recited in claim 20 wherein modulation of said radial actuator system comprises movement from a center of a disk being mastered at rates that vary randomly between a nominal speed and fractionally more than said nominal speed.

22. An apparatus for master recording copy protected material on a recording medium comprising:

means for coupling a digital data stream to a symmetrical encryptor;

means for generating a first key signal;

means for symmetrically encrypting said digital data stream using said first key signal;

means for coupling data to an asymmetrical encryptor;

means for selecting between said digital data stream and symmetrically encrypted data;

means for generating a second key signal;

means for asymmetrically encrypting selected data using said second key signal;

means for coupling asymmetrically decrypted data to a data processing portion of a master recording device;

means for generating an authentication signature signal to indicate that said digital data stream is to be copy protected;

means for selecting between a copy protection mode and a non-copy protect mode; and

means for affecting a time base system of said recording medium in response to said authentication signature signal.

23. An apparatus as recited in claim 22 wherein said first key signal is a random key.

24. An apparatus as recited in claim 22 wherein said second key signal is a secret key.

25. A copy protection apparatus for a playback device, comprising:

means for coupling a decoded data signal to an asymmetrical decryptor;

means for generating a first key signal;

means for asymmetrically decrypting said decoded data signal by using said first key signal;

means for generating a second key signal;

means for coupling an asymmetrically decrypted data signal to a symmetrical decryptor;

means for symmetrically decrypting asymmetrically decrypted data using said second key signal to generate a clear data signal;

means for selecting between asymmetrically decrypted data from said asymmetrical decryptor and symmetrically decrypted data from said symmetrical decryptor;

means for detecting an authentication signature signal to indicate that said clear data signal is to be copy protected; and

means for selecting between a copy protection mode and a non-copy protect mode for indicating whether said decoded data signal is copy protected or not copy protected.