Copyright protection system, recording device, and reproduction device

• US 20030152222A1
• Filed: 08/07/2002
• Published: 08/14/2003
• Est. Priority Date: 08/08/2001
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Nakano, Toshihisa, Tatebayashi, Makoto, Matsuzaki, Natsume, Harada, Shunji
• Granted Patent: US 7,555,779 B2
• Time in Patent Office: Days
• US Class Current: 380/201
• CPC Class Codes: G06F 21/1014 to tokens
• CPC Class Codes: G06F 21/107 License processing; Key processing
• CPC Class Codes: G06F 21/78 to assure secure storage of data address-based protection against unauthorised use of memory G06F12/14; record carriers for use with machines and with at least a part designed to carry digital markings G06K19/00
• 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 20/00094 involving measures which result in a restriction to authorised record carriers
• CPC Class Codes: G11B 20/00173 wherein the origin of the content is checked, e.g. determining whether the content has originally been retrieved from a legal disc copy or another trusted source
• 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 20/00253 wherein the key is stored on the record carrier
• CPC Class Codes: G11B 20/00347 wherein the medium identifier is used as a key
• CPC Class Codes: G11B 20/00492 wherein content or user data is encrypted
• CPC Class Codes: G11B 20/00514 wherein the entire content is encrypted with the same key, e.g. disc key or master key
• CPC Class Codes: G11B 20/0055 wherein license data is encrypted
• CPC Class Codes: G11B 20/00847 wherein the usage restriction is defined by a licence file
• CPC Class Codes: G11B 20/00855 involving a step of exchanging information with a remote server
• CPC Class Codes: G11B 2220/2537 Optical discs

Abstract

A copyright protection system includes a recording device and a reproduction device. The recording device writes encrypted content, an encrypted content key for decrypting the encrypted content, and license information on a recording medium on which a unique media number has been recorded in an unrewritable state. The license information is generated using both the media number and the encrypted content key, and therefore reflects both values. The reproduction device reads the media number, the encrypted content key, and the license information from the recording medium, and judges whether the license information reflects both the media number and the encrypted content key. Only if the license information reflects both values, the reproduction device decrypts the encrypted content key, and decrypts the encrypted content using the content key. In this way, the copyright protection system allows only original recording media to be reproduced, and prohibits reproduction of copy recording media.

Claims

1. A copyright protection system comprising a recording device for recording encrypted content on a recording medium and a decryption device for decrypting the encrypted content recorded on the recording medium, the recording medium having an unrewritable area in which a media number unique to the recording medium is recorded,

the recording device including:

a generating unit operable to acquire the media number from the recording medium, and generate license information by performing a specific operation using the media number and decryption information so that the license information reflects both the media number and the decryption information, the decryption information being necessary to decrypt the encrypted content; and

a recording unit operable to record the license information, the decryption information, and the encrypted content on the recording medium, and

the decryption device including;

a judging unit operable to read the media number, the decryption information, and the license information from the recording medium, and judge whether the read license information can be obtained if the specific operation is performed using the read media number and the read decryption information; and

a decrypting unit operable to read the encrypted content from the recording medium and decrypt the encrypted content using the decryption information, only if the judgement by the judging unit is in the affirmative.

2. The copyright protection system of claim 1,

wherein the decrypting unit includes:

a decryption key computing unit operable to perform a predetermined computation on the decryption information, to obtain a decryption key for decrypting the encrypted content, and

the decrypting unit decrypts the encrypted content using the decryption key.

3. The copyright protection system of claim 2,

wherein the recording device further includes:

a recording device possessing unit operable to possess a secret key, by either acquiring the secret key from outside or storing the secret key in advance; and

a decryption key encrypting unit operable to encrypt the decryption key using the secret key according to a secret key cipher, to generate the decryption information,

the decryption device further includes;

a decryption device possessing unit operable to possess the same secret key as the recording device possessing unit, by either acquiring the secret key from outside or storing the secret key in advance, and

the decryption key computing unit decrypts the decryption information using the secret key according to the secret key cipher, to obtain the decryption key.

4. The copyright protection system of claim 3,

wherein the generating unit performs the specific operation using the secret key in addition to the media number and the decryption information, and

the judging unit makes the judgement using the secret key in addition to the read media number and the read decryption information.

5. The copyright protection system of claim 3,

wherein secret key information has been recorded in the unrewritable area of the recording medium, the secret key information being an encrypted secret key which can be correctly decrypted only when a specific device key is used,

each of the recording device possessing unit and the decryption device possessing unit includes:

a device key storing unit operable to store a device key unique to a device to which the device key storing unit belongs, in advance;

a secret key decrypting unit operable to decrypt the secret key information recorded on the recording medium using the device key in the device key storing unit; and

a secret key storing unit operable to store, only if the secret key decrypting unit has succeeded in correctly decrypting the secret key information to acquire the secret key, the acquired secret key, and

each of the recording device and the decryption device further includes;

a stopping unit operable to stop subsequent processing if the secret key decrypting unit has failed to correctly decrypt the secret key information.

6. The copyright protection system of claim 1,

wherein the judging unit includes:

a reference license information generating unit operable to perform the specific operation using the read media number and the read decryption information, to generate reference license information; and

a comparing unit operable to (a) compare the reference license information with the read license information, (b) judge in the affirmative if the reference license information matches the read license information, and (c) judge in the negative if the reference license information does not match the read license information.

7. The copyright protection system of claim 1,

wherein the generating unit generates a set of license information for each of a plurality of sets of encrypted content, by performing the specific operation on the media number and a set of decryption information which corresponds to the set of encrypted content,

the recording unit records the plurality of sets of encrypted content, a plurality of sets of decryption information which are in a one-to-one correspondence with the plurality of sets of encrypted content, and a plurality of sets of license information which are generated by the generating unit and are in a one-to-one correspondence with the plurality of sets of encrypted content, on the recording medium in combination, and

the judging unit and the decrypting unit respectively perform the judgement and the decryption on each combination recorded on the recording medium.

8. The copyright protection system of claim 1,

wherein the generating unit generates a set of license information for a plurality of sets of encrypted content, by performing the specific operation on the media number and a plurality of sets of decryption information which are in a one-to-one correspondence with the plurality of sets of encrypted content.

9. A recording device for recording encrypted content on a recording medium, the recording medium having an unrewritable area in which a media number unique to the recording medium is recorded, comprising:

a generating unit operable to acquire the media number from the recording medium, and generate license information by performing a specific operation using the media number and decryption information so that the license information reflects both the media number and the decryption information, the decryption information being necessary to decrypt the encrypted content; and

a recording unit operable to record the license information, the decryption information, and the encrypted content on the recording medium.

10. A decryption device for decrypting encrypted content recorded on a recording medium, wherein the encrypted content, decryption information necessary to decrypt the encrypted content, and license information used for judging whether the encrypted content is permitted to be decrypted are recorded on the recording medium, and the recording medium has an unrewritable area in which a media number unique to the recording medium is recorded, comprising:

a judging unit operable to read the media number, the decryption information, and the license information from the recording medium, and judge whether the read license information can be obtained if a specific operation is performed using the read media number and the read decryption information; and

a decrypting unit operable to read the encrypted content from the recording medium and decrypt the encrypted content using the decryption information, only if the judgement by the judging unit is in the affirmative.

11. A copyright protection method for use in a copyright protection system including a recording device for recording encrypted content on a recording medium and a decryption device for decrypting the encrypted content recorded on the recording medium, the recording medium having an unrewritable area in which a media number unique to the recording medium is recorded, comprising:

a generating step, performed by the recording device, of acquiring the media number from the recording medium, and generating license information by performing a specific operation using the media number and decryption information so that the license information reflects both the media number and the decryption information, the decryption information being necessary to decrypt the encrypted content;

a recording step, performed by the recording device, of recording the license information, the decryption information, and the encrypted content on the recording medium;

a judging step, performed by the decryption device, of reading the media number, the decryption information, and the license information from the recording medium, and judging whether the read license information can be obtained if the specific operation is performed using the read media number and the read decryption information; and

a decrypting step, performed by the decryption device, of reading the encrypted content from the recording medium and decrypting the encrypted content using the decryption information, only if the judgement in the judging step is in the affirmative.

12. A recording method for recording encrypted content on a recording medium, the recording medium having an unrewritable area in which a media number unique to the recording medium is recorded, comprising:

a generating step of acquiring the media number from the recording medium, and generating license information by performing a specific operation using the media number and decryption information so that the license information reflects both the media number and the decryption information, the decryption information being necessary to decrypt the encrypted content; and

a recording step of recording the license information, the decryption information, and the encrypted content on the recording medium.

13. A decryption method for decrypting encrypted content recorded on a recording medium, wherein the encrypted content, decryption information necessary to decrypt the encrypted content, and license information used for judging whether the encrypted content is permitted to be decrypted are recorded on the recording medium, and the recording medium has an unrewritable area in which a media number unique to the recording medium is recorded, comprising:

a judging step of reading the media number, the decryption information, and the license information from the recording medium, and judging whether the read license information can be obtained if a specific operation is performed using the read media number and the read decryption information; and

a decrypting step of reading the encrypted content from the recording medium and decrypting the encrypted content using the decryption information, only if the judgement in the judging step is in the affirmative.

14. A recording program for use in a recording device for recording encrypted content on a recording medium, the recording medium having an unrewritable area in which a media number unique to the recording medium is recorded, the recording program having the recording device execute:

a generating step of acquiring the media number from the recording medium, and generating license information by performing a specific operation using the media number and decryption information so that the license information reflects both the media number and the decryption information, the decryption information being necessary to decrypt the encrypted content; and

a recording step of recording the license information, the decryption information, and the encrypted content on the recording medium.

15. A decryption program for use in a decryption device for decrypting encrypted content recorded on a recording medium, wherein the encrypted content, decryption information necessary to decrypt the encrypted content, and license information used for judging whether the encrypted content is permitted to be decrypted are recorded on the recording medium, and the recording medium has an unrewritable area in which a media number unique to the recording medium is recorded, the decryption program having the decryption device execute:

a judging step of reading the media number, the decryption information, and the license information from the recording medium, and judging whether the read license information can be obtained if a specific operation is performed using the read media number and the read decryption information; and

a decrypting step of reading the encrypted content from the recording medium and decrypting the encrypted content using the decryption information, only if the judgement in the judging step is in the affirmative.

16. A computer-readable storage medium storing a recording program for use in a recording device for recording encrypted content on a recording medium, the recording medium having an unrewritable area in which a media number unique to the recording medium is recorded, the recording program having the recording device execute:

a generating step of acquiring the media number from the recording medium, and generating license information by performing a specific operation using the media number and decryption information so that the license information reflects both the media number and the decryption information, the decryption information being necessary to decrypt the encrypted content; and

a recording step of recording the license information, the decryption information, and the encrypted content on the recording medium.

17. A computer-readable storage medium storing a decryption program for use in a decryption device for decrypting encrypted content recorded on a recording medium, wherein the encrypted content, decryption information necessary to decrypt the encrypted content, and license information used for judging whether the encrypted content is permitted to be decrypted are recorded on the recording medium, and the recording medium has an unrewritable area in which a media number unique to the recording medium is recorded, the decryption program having the decryption device execute:

a judging step of reading the media number, the decryption information, and the license information from the recording medium, and judging whether the read license information can be obtained if a specific operation is performed using the read media number and the read decryption information; and

a decrypting step of reading the encrypted content from the recording medium and decrypting the encrypted content using the decryption information, only if the judgement in the judging step is in the affirmative.

18. A recording medium comprising:

an unrewritable area in which a media number unique to the recording medium is recorded; and

a rewritable area in which (a) encrypted content, (b) decryption information necessary to decrypt the encrypted content, and (c) license information that is obtained by a specific operation using the media number and the decryption information and that reflects both the media number and the decryption information are recorded.