Digital signal recording and playback apparatus

• US 20070183747A1
• Filed: 12/27/2006
• Published: 08/09/2007
• Est. Priority Date: 02/03/2006
• Status: Abandoned Application

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Katsumata, Kenji, Watanabe, Akinobu
• Application Number:
  US11/646,801
• Publication Number:
  US 20070183747A1
• Time in Patent Office: Days
• US Class Current: 386/257
• CPC Class Codes: H04N 2005/91328 the copy protection signal being a copy management signal, e.g. a copy generation management signal [CGMS]
• CPC Class Codes: H04N 21/42669 the medium being removable
• CPC Class Codes: H04N 21/4334 Recording operations recording of a television signal H04N5/76; arrangements for recording or accumulating broadcast information or broadcast-related information H04H60/27
• CPC Class Codes: H04N 21/4405 involving video stream decryption
• CPC Class Codes: H04N 21/4627 Rights management associated to the content security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08
• CPC Class Codes: H04N 21/8355 involving usage data, e.g. number of copies or viewings allowed
• CPC Class Codes: H04N 5/76 Television signal recording

Abstract

An object of the present invention is to provide a digital signal recording and playback apparatus for, even in the case of a program whose recording is not permitted (for example, Never Copy), performing, on the digital signal receiving side, recording and playback control that is limited to time shifting. In order to achieve the above object, there is provided a digital signal recording and playback apparatus that writes digital signals to different recording areas on the recording medium, the recording areas including a first recording area to which an ordinary digital signal is written, and a second recording area to which an encrypted digital signal having a copy restriction control flag is written, the digital signal recording and playback apparatus erasing, under specified conditions, an encryption key of the digital signal written to the second recording area.

Claims

1. A digital signal recording and playback apparatus for recording an inputted digital signal to a recording medium, and for playing back the digital signal from the recording medium, the digital signal recording and playback apparatus comprising:

a recording control module which controls recording of the digital signal to the recording medium;

a playback control module which controls playback of the digital signal from the recording medium;

an encryption module which encrypts the digital signal;

a decryption module which decrypts the encrypted digital signal; and

a control module which controls the recording control module, the encryption module, the decryption module, and the playback control module;

wherein;

a control flag relating to copy control or playback control is added to the inputted digital signal; and

the control module performs control so that digital signals are recorded to a first and second recording areas on the recording medium, the first recording area storing an ordinary digital signal, the second recording area storing the digital signal including the added control flag after the digital signal is encrypted, the control module further performing control so that an encryption key of the digital signal recorded to the second recording area is erased under a specified condition.

2. The digital signal recording and playback apparatus according to claim 1, wherein:

the control flag indicates that the inputted digital signal is Copy Never content.

3. The digital signal recording and playback apparatus according to claim 1, wherein:

the control module performs control so that playback of the digital signal recorded to the second recording area is permitted only for the purpose of time shift playback.

4. The digital signal recording and playback apparatus according to claim 3, wherein:

the control module performs control so that the inputted digital signal is recorded to the second recording area in rotation.

5. The digital signal recording and playback apparatus according to claim 1, wherein:

the first and second recording areas are partitions.

6. The digital signal recording and playback apparatus according to claim 1, wherein:

the specified condition is the time at the end of recording.

7. The digital signal recording and playback apparatus according to claim 1, wherein:

the specified condition is the time of the first access after the end of recording.

8. The digital signal recording and playback apparatus according to claim 1, wherein:

the specified condition is the time of turning off the power supplied to the digital signal recording and playback apparatus.

9. The digital signal recording and playback apparatus according to claim 1, further comprising a nonvolatile memory module which stores the encryption key, wherein:

the encryption key of the encrypted digital signal to be recorded to the recording medium is stored in the nonvolatile memory module.

10. The digital signal recording and playback apparatus according to claim 1, wherein:

the recording medium is a removable recording medium.

11. The digital signal recording and playback apparatus according to claim 1, wherein:

the recording medium includes an authentication module which performs authentication.

12. The digital signal recording and playback apparatus according to claim 11, wherein:

only when the authentication is successfully completed between the authentication module and the detection control module, the second recording medium becomes accessible.

13. A digital signal recording and playback apparatus for recording an inputted digital signal to a recording medium, and for playing back the digital signal from the recording medium, the digital signal recording and playback apparatus comprising:

a recording control module which controls recording of the digital signal to the recording medium;

a playback control module which controls playback of the digital signal from the recording medium;

an encryption module which encrypts the digital signal;

a decryption module which decrypts the encrypted digital signal; and

a control module which controls the recording control module, the encryption module, the decryption module, and the playback control module;

wherein;

a playback control flag relating to playback restrictions is added to the inputted digital signal; and

the control module performs control so that digital signals are recorded to a first recording area and a second recording area on the recording medium, the first recording area storing an ordinary digital signal, the second recording area storing the digital signal including the added control flag after the digital signal is encrypted, the control module further performing control so that an encryption key of the digital signal recorded to the second recording area is erased under specified conditions.