Digital signal recording/reproducing apparatus

• US 6,804,453 B1
• Filed: 05/15/2000
• Issued: 10/12/2004
• Est. Priority Date: 05/13/1999
• Status: Expired due to Fees

• Current Assignee: Maxell, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Takahashi, Masaru, Takeuchi, Toshifumi, Okamoto, Hiroo, Sasamoto, Manabu
• Primary Examiner(s): Chevalier, Robert
• Application Number:
  US09/571,656
• Time in Patent Office: 1,611 Days
• Field of Search: H04/N.591, H04/N.708, 386/94, 386/95, 386/92, 386/109, 386/83, 386/124, 386/125, 386/126, 386/40, 386/45, 386/46, 386/27, 386/33, 380/201, 380/200, 380/202, 380/203, 380/239, 380/277, 380/278, 380/210, 380/217, 713/193, 360/15
• US Class Current: 386/258
• CPC Class Codes: H04L 2209/605 Copy protection
• CPC Class Codes: H04L 9/0869 involving random numbers or seeds
• CPC Class Codes: H04N 2005/91364 the video signal being scrambled
• 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

Abstract

A digital signal recording apparatus is disclosed, which is capable of protecting the copyright of the analog input information encoded into a first digital signal in a recording medium. A second digital signal encrypted based on the key information and the input analog signal encrypted based on the key information are converted into a second digital signal and encrypted, and the resulting signal is selectively recorded in a recording medium. The digital signal recording apparatus further comprises a circuit for encrypting the digital signal converted from the input analog signal with a key obtained by a predetermined calculation of the key information according to a scheme similar to the second digital signal protection scheme through a digital interface, and a signal recording circuit for recording the key information and the encrypted digital signal in a recording medium.

Claims

1. A digital signal recording apparatus further comprising:

a first input circuit which inputs an analog signal;

a converter which converts said analog signal into a first digital signal;

a key information generating circuit which generates first key information;

a key generating circuit which performs a predetermined calculation and generates a key;

an encryption circuit which encrypts said first digital signal with said key;

a second input circuit which inputs a second digital signal encrypted based on second key information, and said second key information; and

a recording circuit which selects and records an encrypted first digital signal or an encrypted second digital signal, together with the corresponding one of the first and second key information in a predetermined area on a recording medium.

2. A digital signal recording apparatus according to claim 1, wherein said first digital signal and said second digital signal have a packet format of a predetermined length.

3. A digital signal recording apparatus according to claim 1,

wherein said key information generating circuit has a function of updating said at least one first key information at predetermined time intervals, and

wherein said recording circuit has such a function that timing information capable of identifying the timing at which said key information generating circuit updates said first key information is recorded in a predetermined are of said recording medium.

4. A digital signal recording apparatus according to claim 3,

wherein said first digital signal has a packet format of a predetermined length, and

wherein said recording circuit has such a function that the timing information capable of identifying the timing at which said key information generating circuit updates said first key information is added to each packet of said first digital signal and recorded on said recording medium.

5. A digital signal recording apparatus according to claim 1,

wherein said encryption circuit is capable of selecting the function of outputting by encrypting said first digital signal and the function of outputting said first digital signal without encryption;

and

wherein said recording circuit has such a function that encryption flag information indicating whether said first digital signal is encrypted or not is recorded in a predetermined area of said recording medium.

6. A digital signal recording apparatus according to claim 5,

wherein said first digital signal has a packet format of a predetermined length;

and

wherein said recording circuit has such function that the encryption flag information indicating whether said first digital signal is encrypted or not is attached to each packet of said first digital signal and recorded on said recording medium.

7. A digital signal recording apparatus according to claim 2,

wherein said recording circuit records the first or second digital signal encrypted in the format of each sector having a plurality of packets and a control data area in said recording medium and dividing said first or second key information, assigns and records divided key information among control data areas of a plurality of said sectors.

8. A digital signal recording/reproducing apparatus comprising:

an analog signal input/output terminal;

an A/D converter which converts an analog signal input, via said analog signal input/output terminal, into a first digital signal;

a key information generating circuit which generates at least one first key information for signal encryption/decryption;

a key generating circuit which is supplied with said first key information, and which generates a key by performing a predetermined calculation;

an encryption circuit which is supplied with said key and said first digital signal, and which encrypts said first digital signal with said key;

an input circuit which inputs a second digital signal encrypted based on second key information, and said second key information;

a recording circuit which records said at least one first or second key information and an encrypted first or second digital signal in a predetermined area on a recording medium;

said recording circuit selecting either said encrypted first digital signal with said first key information or said encrypted second digital signal with said second key information, and recording the selected signal in a predetermined area on said recording medium;

a reproducing circuit which selectively reproduces said encrypted first digital signal with said first key information or said encrypted second digital signal with said second key information from said recording medium;

a decryption circuit which generates a key based on said first or second key information from said reproducing circuit, and which decrypts a reproduced first or second digital signal or said second digital signal using said key; and

a D/A converter which converts a decrypted digital signal into an analog signal and outputs to said analog signal input/output terminal.

9. A digital signal recording/reproducing apparatus according to claim 8, further comprising:

a circuit for selecting the output of said reproducing circuit; and

an output circuit for outputting reproduced first key information with said encrypted first digital signal or reproduced second key information with said encrypted second digital signal selected by said recording circuit,

wherein said output circuit and said input circuit is configured with a digital interface.

10. A digital signal recording/reproducing apparatus according to claim 8, further comprising:

an encoder/decoder which compresses a digitally encoded signal or expands a compressed digital signal; and

a packet converter for packetizing the compressed digital signal or restoring packets into the original digital signal,

wherein said encoder/decoder and said packet converter are interposed between said A/D converter, said D/A converter and said encryption circuit and said decryption circuit.

11. A digital signal recording/reproducing apparatus according to claim 10,

wherein said recording medium is an optical disc, and said encrypted first or second digital signal and said first or second key information are recorded on said optical disc in the format of a plurality of sectors each including a plurality of packets.

12. A digital signal recording/reproducing apparatus according to claim 11,

wherein said first or second key information is segmented and segmented key information is recorded distributively among a plurality of said sectors on said optical disc.

13. A digital signal recording/reproducing apparatus according to claim 12,

wherein said sectors each includes a user data area and a control data area, said segmented key information is formatted before recorded in said control data area of each sector on said optical disc.

14. A digital signal recording apparatus comprising:

a converter supplied with an analog signal for converting said analog signal into a first digital signal;

key information generating means for generating at least one first key information;

key generating means supplied with said first key information and performing a predetermined calculation and generating a key;

encrypting means supplied with said key and said first digital signal for encrypting said first digital signal with said key;

input means for inputting a second digital signal encrypted based on second key information, and said second key information; and

recording means for recording at least an encrypted first digital signal together with said first key information, or an encrypted second digital signal together with said second key information, in a predetermined area on a recording medium,

wherein said key information generating means has a function of updating said at least one first key information at predetermined time intervals, and

said recording means has such a function that the information capable of identifying the timing at which said key information generating means updates said first key information is recorded in a predetermined area on said recording medium.

15. A digital signal recording/reproducing apparatus comprising:

an analog signal input/output terminal;

an A/D converter for converting an analog signal input, via said analog signal input/output terminal, into a first digital signal;

key information generating means for generating at least one first key information for a signal encryption/decryption;

key generating means supplied with said first key information for generating a key by performing a predetermined calculation;

encryption means supplied with said key and said first digital signal for encrypting and outputting an encrypted first digital signal with said key;

an input circuit for inputting a second digital signal encrypted based on second key information, and said second key information;

a recording circuit for recording said at least one key first or second information and said encrypted first or second digital signal in a predetermined area on a recording medium;

said recording circuit selecting either said first key information with said encrypted first digital signal or said second key information with said encrypted second digital signal, and recording the selected signal in a predetermined area on said recording medium;

a reproducing circuit for selectively reproducing said encrypted first digital signal with said first key information or said second key information with said encrypted second digital signal from said recording medium;

decryption means for generating a key based on said first or second key information from said reproducing circuit and decrypting said reproduced first digital signal or said reproduced second digital signal using said key; and

D/A converter for converting a decrypted digital signal into an analog signal and outputting to said analog signal input/output terminal.

16. A digital signal recording/reproducing apparatus according to claim 15, further comprising:

encoder/decoder means for compressing a digitally encoded signal or expanding a compressed digital signal; and

packet converting means for packetizing the compressed digital signal or restoring packets into the original digital signal,

wherein said encoder/decoder means and said packet converting means are interposed between said A/D converter, said D/A converter and said encryption means and said decryption means.

17. A digital signal recording apparatus comprising:

a first input circuit which inputs an analog signal;

a converter which converts said analog signal into a first digital signal;

a second input circuit which inputs a second digital signal; and

a recording circuit which records one of said first digital signal and said second digital signal in a predetermined area of a recording medium,

wherein said recording circuit records one of said first digital signal and said second digital signal, which is encrypted with a compatible method on said recording medium.

18. A digital signal recording apparatus according to claim 17, wherein said first digital signal and said second digital signal have a packet format of a predetermined length.