Information access control method and apparatus

• US 20070288766A1
• Filed: 06/11/2007
• Published: 12/13/2007
• Est. Priority Date: 06/13/2006
• Status: Abandoned Application

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Kamio, Hiroyuki, Tachikawa, Takayuki
• Application Number:
  US11/808,471
• Publication Number:
  US 20070288766A1
• Time in Patent Office: Days
• US Class Current: 713/193
• 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 20/00362 the key being obtained from a media key block [MKB]
• CPC Class Codes: G11B 20/00427 advanced access content system [AACS]
• 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 20/00666 involving a step of erasing or nullifying data, e.g. data being overwritten with a random string
• CPC Class Codes: G11B 2220/216 Rewritable discs
• CPC Class Codes: G11B 2220/218 Write-once discs
• CPC Class Codes: G11B 2220/2504 Holographic discs; Holographic digital data storage [HDDS]
• CPC Class Codes: G11B 2220/2516 Hard disks
• CPC Class Codes: G11B 2220/2562 DVDs [digital versatile discs]; Digital video discs; MMCDs; HDCDs
• CPC Class Codes: G11B 2220/2579 HD-DVDs [high definition DVDs]; AODs [advanced optical discs]
• CPC Class Codes: G11B 27/034 on discs G11B27/036, G11B27/038 take precedence
• CPC Class Codes: H04N 2005/91364 the video signal being scrambled
• CPC Class Codes: H04N 5/765 Interface circuits between an apparatus for recording and another apparatus
• CPC Class Codes: H04N 5/775 between a recording apparatus and a television receiver
• CPC Class Codes: H04N 5/781 on disks or drums
• CPC Class Codes: H04N 5/85 on discs or drums
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection
• CPC Class Codes: H04N 9/7921 : for more than one processing mode
• CPC Class Codes: H04N 9/8042 : involving data reduction
• CPC Class Codes: H04N 9/8063 : using time division multiplex of the PCM audio and PCM video signals
• CPC Class Codes: H04N 9/8227 : the additional signal being at least another television signal

Abstract

According to one embodiment, an access management system such as an AACS is used to protect highly confidential information. A specific content is deleted from a medium on which recorded are one or more contents or objects being encrypted using an encryption key (or Title Key) according to the AACS. When the contents are to be deleted, the contents and the encryption key will be deleted simultaneously, provided that the information medium does not record another content or another object encrypted using an encryption key which is equivalent to the encryption key used for encrypting the contents to be deleted.

Claims

1. An access management method for deleting a specific content or contents from an information medium on which recorded are one or more contents or objects being encrypted using an encryption key according to a given encryption system, said method comprising:

deleting the contents and the encryption key when the contents are to be deleted, provided that the information medium does not record another content or another object encrypted using an encryption key which is equivalent to the encryption key used for encrypting the contents to be deleted.

2. The method of claim 1, wherein when the contents are to be moved to a medium other than the information medium from which the contents are to be deleted, even if the information medium records another content or another object encrypted using an encryption key which is equivalent to the encryption key used for encrypting the contents to be moved, the encryption key is deleted with the contents move.

3. The method of claim 1, wherein when the deletion of the contents is independent of or has no relation to the contents move, and if the information medium records another content or another object encrypted using an encryption key which is equivalent to the encryption key used for encrypting the contents to be moved, the encryption key is not deleted while the contents are deleted.

5. The method of claim 1, wherein when the contents are to be moved to a medium other than the information medium from which the contents are to be deleted, showing or alarming that the information medium records another content or another object encrypted using an encryption key which is equivalent to the encryption key used for encrypting the contents to be moved, and if the contents are moved, then the encryption key is deleted when or after the contents are moved.

6. An information recording/reproducing apparatus configured to perform the method of claim 5, said apparatus comprising:

a recorder/reproducer configured to record the contents or the objects which are accessible using the encryption key on the information medium or to reproduce the contents or the objects from the information medium; and

an indicator configured to show or alarm that the information medium records another content or another object encrypted using an encryption key which is equivalent to the encryption key used for encrypting the contents to be moved.

4. A method for reproducing encrypted object data from an information medium wherein the encrypted object data is encrypted using an encryption key, said reproducing method comprising:

reading information relating to an encryption from the information medium;

generating a decryption key corresponding to the encryption key from the read encryption-related information; and

decrypting and reproducing data of the encrypted object or encrypted contents from the information medium according to the generated decryption key.