Method for managing copy protection information of recording medium

• US 20040213112A1
• Filed: 04/26/2004
• Published: 10/28/2004
• Est. Priority Date: 04/24/2003
• Status: Abandoned Application

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Byung Jin, Kim, Hyung Sun
• Application Number:
  US10/831,170
• Publication Number:
  US 20040213112A1
• Time in Patent Office: Days
• US Class Current: 369/53.21
• 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 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00239 wherein the key is provided by a software application accessing the medium
• 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 20/00304 the key being stored in the lead-in area [LIA]
• CPC Class Codes: G11B 20/00369 wherein a first key, which is usually stored on a hidden channel, e.g. in the lead-in of a BD-R, unlocks a key locker containing a second
• CPC Class Codes: G11B 20/00405 the key being stored by varying characteristics of the recording track, e.g. by altering the track pitch or by modulating the wobble track
• CPC Class Codes: G11B 20/00507 wherein consecutive physical data units of the record carrier are encrypted with separate encryption keys, e.g. the key changes on a cluster or sector basis
• CPC Class Codes: G11B 20/00528 wherein each title is encrypted with a separate encryption key for each title, e.g. title key for movie, song or data file
• CPC Class Codes: G11B 7/00736 Auxiliary data, e.g. lead-in, lead-out, Power Calibration Area [PCA], Burst Cutting Area [BCA], control information sector headers or adresses in prepits G11B7/00745; address data in track wobble G11B7/24082
• CPC Class Codes: G11B 7/26 Apparatus or processes specially adapted for the manufacture of record carriers

Abstract

A method for managing copy protection information of a recording medium is disclosed. Copy protection information for decrypting A/V data encrypted and recorded in a data area of an optical disc is recorded in a key locker of the disc. Information of makers that have manufactured optical disc drives, drive maker keys of each maker and flags indicating whether drive keys are valid or not is included in association with each other in the key locker. To reproduce the A/V data, the copy protection information is read and decrypted by comparing a drive key managed in the optical disc drive with the key renewal information recorded in the optical disc. Accordingly, illegally duplicated optical disc drives can no longer perform a normal playback operation, thereby effectively suppressing illegal duplication of optical disc drives, which also prevents optical disc drives of all makers from being duplicated at once.

Claims

1. A method for managing copy protection information of a recording medium, comprising:

recording copy protection information in a first specific area of a recording medium, said copy protection information being used for decrypting data encrypted and recorded in a data area of the recording medium;

recording a first key in a second specific area of the recording medium, said first key being used for decrypting the copy protection information; and

recording key renewal information in the first specific area, said key renewal information indicating whether a second key required to decrypt the copy protection information is valid or not,

wherein the second key is managed in a drive or an application for playing recording mediums.

2. The method according to claim 1, wherein the first key is a hidden code recorded in the form of a wobble having a low frequency component that is not duplicated using a bit to bit copy;

the second key is a unique key identified by a unique drive ID of a maker that has manufactured the drive; and

the copy protection information is a recording medium key recorded after being encrypted.

3. The method according to claim 1, wherein information of a maker that has manufactured the drive, information of second keys of each maker, and information of flags indicating whether second keys are valid or not are included in association with each other in the key renewal information.

4. A recording medium comprising:

a data area in which data encrypted using copy protection information is recorded;

a first specific area in which the copy protection information and key renewal information are recorded, said key renewal information indicating whether a second key required to decrypt the copy protection information is valid or not; and

a second specific area in which a first key for decrypting the copy protection information is recorded.

5. The medium according to claim 4, wherein the copy protection information is a disc key encrypted and recorded in the first specific area, said copy protection information being decrypted by a combination of the first key and the second key, said second key being managed in a drive for playing the recording medium.

6. The medium according to claim 5, wherein the second key is a drive key or an application key.

7. The medium according to claim 4, wherein the first key is a hidden code recorded in the form of a wobble having a low frequency component that is not duplicated using a bit to bit copy.

8. The medium according to claim 4, wherein information of a maker that has manufactured a drive or an application for playing recording mediums, information of second keys of each maker, and information of flags indicating whether second keys are valid or not are included in association with each other in the key renewal information.

9. A method for managing copy protection information of a recording medium, the method comprising the steps of:

a) reading key renewal information in a first specific area of a recording medium using a first key and a second key, said first key being read from a second specific area of the recording medium, said second key being managed in a drive or an application for playing the recording medium;

b) determining, based on the read key renewal information, whether the second key is valid or not; and

c) decrypting copy protection information, recorded in the first specific area, using the first and second keys according to the determination at said step b).

10. The method according to claim 9, wherein the first key is a hidden code recorded in the form of a wobble having a low frequency component that is not duplicated using a bit to bit copy;

the second key is a drive key or an application key; and

the key renewal information is recorded in a key locker.

11. The method according to claim 9, wherein information of a maker that has manufactured a drive or an application for playing recording mediums, information of second keys of each maker, and information of flags indicating whether second keys are valid or not are included in association with each other in the key renewal information.

12. The method according to claim 11, wherein the copy protection information recorded in the first specific area is decrypted using the first and second keys if it is determined that the second key is valid, based on a flag corresponding to the second key managed in the drive or application, said flag being included in the key renewal information.

13. The method according to claim 11, wherein the copy protection information recorded in the first specific area is not decrypted if it is determined that the second key is invalid, based on a flag corresponding to the second key managed in the drive or application, said flag being included in the key renewal information.