Backup Management Device, Backup Management Method, Computer Program, Recording Medium, Integrated Circuit, and Backup System

• US 20080310628A1
• Filed: 01/30/2006
• Published: 12/18/2008
• Est. Priority Date: 01/31/2005
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nakano, Toshihisa, Ito, Yoshikatsu, Tsusaka, Yuko, Ohmori, Motoji, Harada, Shunji, Fujioka, Soichiro
• Granted Patent: US 7,991,155 B2
• Time in Patent Office: Days
• US Class Current: 380/201
• CPC Class Codes: G06F 11/1448 Management of the data involved in backup or backup restore
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• CPC Class Codes: G06F 11/1456 Hardware arrangements for backup
• CPC Class Codes: G06F 11/1458 Management of the backup or restore process
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 9/0822 using key encryption key
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions

Abstract

To provide a backup management device that deletes a content so as to be restorable in the future while protecting a copyright of the content, in a case where there exists a backup of the content. In an HD recorder 100, a first information storage unit 102 stores a content, a second information storage unit 103 stores a backup of the content, a secure storage unit 104 stores a hash value of the content. If receiving an instruction to delete the content so as to be restorable, a control unit 113 deletes the content from the first information storage unit 102. When the content is played back, an encryption processing unit 109 applies a calculation to the content to generate detection information, and the control unit 113 compares the hash value with the detection information to judge whether the content has been tampered.

Claims

1. A backup management device comprising:

a first storage unit that stores a content;

a secure storage unit that stores playback right information showing a right to play back the content;

a second storage unit that stores a backup of the content;

an acquisition unit operable to acquire an instruction to delete the content so as to be restorable; and

a deletion unit operable, if the instruction is acquired, to delete the content without deleting the playback right information.

2. The backup management device of claim 1, wherein

the playback right information is used for judging whether the backup is permitted to be played back.

3. The backup management device of claim 2, wherein

the playback right information is a hash value generated by applying a calculation using a one-way function to at least part of the content, and

if a value generated by applying the calculation to at least part of a content stored in the first storage unit matches the hash value, the content stored in the first storage unit is permitted to be played back.

4. The backup management device of claim 3, wherein

the content includes:

an encryption key; and

an encrypted work generated by encrypting a digital work using the encryption key,

the playback right information is a hash value generated by applying the calculation to the encryption key, and

if a value generated by applying the calculation to an encryption key included in a content stored in the first storage unit matches the hash value, the content stored in the first storage unit is permitted to be played back.

5. The backup management device of claim 3, wherein

the content includes:

an encrypted work generated by encrypting a digital work using an encryption key; and

an encrypted key generated by encrypting the encryption key using a specific key that is specific to the backup management device,

the playback right information is a hash value generated by applying the calculation to the encrypted key, and

if a value generated by applying the calculation to an encrypted key included in a content stored in the first storage unit matches the hash value, the content stored in the first storage unit is permitted to be played back.

6. The backup management device of claim 3, wherein

the content includes:

an encrypted work generated by encrypting a digital work using an encryption key; and

an encrypted key generated by encrypting the encryption key using a specific key that is specific to the backup management device,

the playback right information is a hash value generated by applying the calculation to at least part of the encrypted work, and

if a value generated by applying the calculation to at least part of an encrypted work included in a content stored in the first storage unit matches the hash value, the content stored in the first storage unit is permitted to be played back.

7. The backup management device of claim 3, wherein

the content includes:

an encrypted work generated by encrypting a digital work using an encryption key; and

an encrypted key generated by encrypting the encryption key using a specific key that is specific to the backup management device,

the playback right information is a hash value generated by applying the calculation to a combination of at least part of the encrypted work and the encrypted key, and

if a value generated by applying the calculation to a combination of at least part of an encrypted work and an encrypted key included in a content stored in the first storage unit matches the hash value, the content stored in the first storage unit is permitted to be played back.

8. The backup management device of claim 2, wherein

the playback right information is a hash value generated by applying a calculation using a one-way function to the content, and

if a value generated by applying the calculation to a content stored in the first storage unit matches the hash value, the content stored in the first storage unit is permitted to be played back.

9. The backup management device of claim 1, wherein

the acquisition unit further acquires a restoration instruction to restore the content, and

the backup management device further comprises

a restoration unit operable, if the restoration instruction is acquired, to read the backup from the second storage unit, and write the read backup to the first storage unit.

10. The backup management device of claim 1, wherein

the acquisition unit further acquires a deletion instruction to delete the content, and

the backup management device further comprises

a complete deletion unit operable, if the deletion instruction is acquired, to delete the backup from the second storage unit, and delete the playback right information from the secure storage unit.

11. The backup management device of claim 1, wherein

the acquisition unit further acquires a move instruction to move the content to another device, and

the backup management device further comprises:

a transmission unit operable, if the move instruction is acquired, to read the backup from the second storage unit, and transmit the read backup to the another device; and

a complete deletion unit operable to delete the backup from the second storage unit, and delete the playback right information from the secure storage unit.

12. A backup management method for use in a backup management device,

the backup management device comprising:

a first storage unit that stores a content;

a secure storage unit that stores playback right information showing a right to play back the content;

a second storage unit that stores a backup of the content;

the backup management method comprising the steps of;

acquiring an instruction to delete the content so as to be restorable; and

deleting, if the instruction is acquired, the content without deleting the playback right information.

13. A computer program for use in a backup management device,

the backup management device comprising:

a first storage unit that stores a content;

a secure storage unit that stores playback right information showing a right to play back the content;

a second storage unit that stores a backup of the content;

the computer program causing a computer to perform the steps of;

acquiring an instruction to delete the content so as to be restorable; and

deleting, if the instruction is acquired, the content without deleting the playback right information.

14. A computer readable recording medium that records the computer program of claim 13.

15. An integrated circuit for use in a backup management device,

the backup management device comprising:

a first storage unit that stores a content;

a secure storage unit that stores playback right information showing a right to play back the content;

a second storage unit that stores a backup of the content;

the integrated circuit comprising the steps of;

acquiring an instruction to delete the content so as to be restorable; and

deleting, if the instruction is acquired, the content without deleting the playback right information.

16. A backup system comprising a recording/playback device that stores and plays back a content and a backup device that manages a backup of the content, wherein

the backup device stores the backup,

the recording/playback device comprises:

a storage unit that stores the content;

a secure storage unit that stores playback right information showing a right to play back the content;

an acquisition unit operable to acquire an instruction to delete the content so as to be restorable; and

a deletion unit operable, if the instruction is acquired, to delete the content without deleting the playback right information, nor instructing the backup system to delete the backup.

17. The backup system of claim 16, wherein

the content and the backup respectively include:

an encrypted work generated by encrypting a digital work using an encryption key; and

an encrypted key generated by encrypting the encryption key using a specific key that is specific to the recording/playback device,

the backup system further comprises a request device,

the request device includes;

a request key storage unit that stores a request key that is specific to the request device;

a transfer request transmission unit operable to transmit a transfer request of the backup to the recording/playback device;

an encryption key receiving unit operable to securely receive the encryption key, as a response to the transfer request, from the recording/playback device; and

a key transmission unit operable, if the encryption key is received, to read the request key, encrypt the encryption key using the read request key to generate a re-encrypted key, and transmit the generated re-encrypted key to the backup device,

the recording/playback device further includes;

a specific key storage unit that stores the specific key;

a transfer request receiving unit operable to receive the transfer request from the request device;

an encrypted key request unit operable, if the transfer request is received, to transmit a transmission request of the encrypted key included in the backup to the backup device;

an encrypted key receiving unit operable to receive the encrypted key, as a response to the transmission request, from the backup device;

an encryption key transmission unit operable, if the encrypted key is received, to read the specific key, decrypt the received encrypted key using the specific key to generate an encryption key, and transmit the generated encryption key to the request device; and

a playback right information deletion unit operable to delete the playback right information from the secure storage unit, and

the backup device includes;

an encrypted key request receiving unit operable to receive the transmission request; and

an encrypted key transmission unit operable, if the transmission request is received, to transmit the encrypted key included in the backup to the recording/playback device.

18. The backup system of claim 16, wherein

the backup includes:

an encrypted work generated by encrypting a digital work using an encryption key; and

an encrypted key generated by encrypting the encryption key using a specific key that is specific to the recording/playback device,

the backup system further comprises a request device,

the request device stores a secret key for decrypting an encryption key encrypted using a public key, and transmits a transfer request of the backup to the recording/playback device,

the recording/playback device further includes;

a transfer request receiving unit operable to receive the transfer request from the request device;

an encrypted key request unit operable, if the transfer request is received, to transmit a transmission request of the encrypted key included in the backup to the backup device;

an encrypted key receiving unit operable to receive the encrypted key, as a response to the transmission request, from the backup device;

a re-encrypted key generation unit that stores beforehand the specific key and the public key, and operable to decrypt the received encrypted key using the specific key to generate the encryption key, and encrypt the generated encryption key using the public key to generate a re-encrypted key;

a transmission unit operable to transmit, to the backup device, a rewriting request including the generated re-encrypted key and for instructing to rewrite the encrypted key included in the backup to the generated re-encrypted key; and

a deletion unit operable to delete the playback right information from the secure storage unit, and

the backup device includes;

an encrypted key request receiving unit operable to receive the transmission request;

an encrypted key transmission unit operable, if the transmission request is received, to transmit the encrypted key included in the backup to the recording/playback device;

a rewriting request receiving unit operable to receive the rewriting request; and

a rewriting unit operable to rewrite the encrypted key included in the backup to the re-encrypted key included in the received rewriting request.

19. A backup management device that manages a backup of a content, comprising

a specific key storage unit that stores a specific key for each device;

a secure storage unit that stores playback right information showing a right to play back the content;

a transfer request receiving unit operable to receive a transfer request of the backup from a request device that stores a first decryption key for decrypting a cyphertext encrypted using a first encryption key;

an encrypted key acquisition unit operable, from a backup device that stores an encrypted key and the backup that has been encrypted, to acquire the encrypted key, the encrypted key being encrypted so as to be decrypted into a second decryption key for decrypting the encrypted backup using the specific key;

a re-encrypted key generation unit operable to generate a re-encrypted key by decrypting the acquired encrypted key using the specific key to generate the second decryption key, and encrypting the generated second decryption key using the first encryption key;

an instruction unit operable to transmit the re-encrypted key to the backup device to instruct the backup device to rewrite the encrypted key stored therein to the re-encrypted key; and

a deletion unit operable to delete the playback right information from the secure storage unit.