Content transmission apparatus, content reception apparatus, content transmission program, and content reception program

• US 7,567,674 B2
• Filed: 10/03/2002
• Issued: 07/28/2009
• Est. Priority Date: 10/03/2001
• Status: Expired due to Fees

• Current Assignee: Nippon Hoso Kyokai
• Original Assignee: Nippon Hoso Kyokai
• Inventors: Uehara, Toshihiro, Namba, Seiichi, Kurioka, Tatsuya, Nishimoto, Yusei
• Primary Examiner(s): Vu; Kim
• Assistant Examiner(s): Dada; Beemnet W
• Application Number:
  US10/433,068
• Publication Number:
  US 20040052379A1
• Time in Patent Office: 2,490 Days
• Field of Search: 380/277, 380/278, 380/281, 380/200, 380/201, 380/282, 713/164, 713/165, 713/167, 713/189
• US Class Current: 380/281
• CPC Class Codes: H04N 21/2347 involving video stream encryption
• CPC Class Codes: H04N 21/4405 involving video stream decryption
• CPC Class Codes: H04N 21/4408 involving video stream encryption, e.g. re-encrypting a decrypted video stream for redistribution in a home network
• CPC Class Codes: H04N 21/835 Generation of protective data, e.g. certificates protecting software against unauthorised usage in a vending or licensing environment G06F21/10
• CPC Class Codes: H04N 7/1675 Providing digital key or authorisation information for generation or regeneration of the scrambling sequence pseudo-random number generators in general G06F7/58

Abstract

A content transmission method, a content reception method, an apparatus and a computer program using same, that improve the efficiency of descrambling a scrambled content, make the management of cryptography keys for descrambling easy, and protect the copyright of contents, are provided. A content transmission apparatus 3 that encrypts and transmits contents and a content reception apparatus 5 that receives the encrypted contents are provided. The content transmission apparatus 3 includes a content scrambling unit 7 that encrypts contents using a scrambling key Ks, a content key , a work key Kw, a master key Km, and a multiplexing unit 9 that transmits multiplexed contents. The content reception apparatus 5 includes a separating unit 13 that receives and separates the multiplexed encrypted content, and a content descrambling unit 15 that obtains the contents by descrambling encrypted information separated by the separating unit 13.

Claims

1. A content transmission apparatus that encrypts and transmits contents of digital broadcasting, comprising:

a storage unit provided with a memory to store a scrambling key that changes as time passes, a content key provided to each content, a network key retained for a time period longer than a duration of the contents, and a master key provided commonly to a receiver side;

a content encryption unit configured to encrypt the contents using the scrambling key into encrypted contents;

a related information encryption unit configured to encrypt first information related to the contents, the first information including at least the scrambling key using the content key into encrypted related information;

a content key related information encryption unit configured to encrypt second information related to the content key, the second information including at least the content key using a work key into encrypted content key related information;

a work key related information encryption unit configured to encrypt third information related to the work key, the third information including at least the work key using the encrypted work key related information into encrypted work key related information;

a multiplexer unit configured to multiplex the encrypted work key related information, the encrypted content key related information, and the encrypted contents; and

a multiplexed encrypted content transmission unit configured to transmit the multiplexed encrypted contents multiplexed by the multiplexer unit,

wherein if a plurality of security modules are correspondingly provided in reception apparatuses at the receiver side, each security module storing decrypted content key related information and being unreadable from exterior, the plurality of security modules being grouped into a plurality of groups, different work keys are used for different groups of the plurality of security modules,

each security module has a plurality of intrinsic keys for encrypting information outputted form the security module, and

the content transmission apparatus further comprises an intrinsic key related information encryption unit configured to encrypt the plurality of intrinsic keys into encrypted intrinsic key related information using the master key.

3. The content transmission apparatus as claimed in claim 1, further comprising a content key related information storage designation unit that, when said encrypted content key related information is decrypted into content key related information at the receiver side, and said content key related information is stored as is, or after being re-encrypted, in a case in which a reception apparatus of said receiver side is provided with at least one of a storing means or a storage medium handling means that handles a storage medium, designates one of said security module, said storing means, and said storage medium to retain said content key related information.

4. The content transmission apparatus as claimed in claim 1, further comprising a content key related information use designation unit that, in a case in which a storage medium handling unit is provided at a receiver side, and said encrypted content is stored therein and said encrypted content is reproduced, if an encrypted content key related information corresponding to said encrypted content is already transmitted, does not use said encrypted content key related information and designates stored content key related information.

5. The content transmission apparatus as claimed in claim 1, wherein at least one of the plurality of intrinsic keys is common to other security modules.

2. A content transmission apparatus that encrypts and transmits contents of digital broadcasting, comprising:

a storage unit provided with a memory to store a scrambling key that changes as time passes, a content key provided to each content, a work key retained for a time period longer than a duration of the scrambling key into encrypted contents;

a related information encryption unit configured to encrypt first information related to the contents, the first information including at least the scrambling key, using the content key into encrypted related information;

a content key related information encryption unit configured to encrypt second information related to the content key, the second information including at least the content key using the work key into encrypted content key related information;

a work key related information encryption unit configured to encrypt third information related to the work key, the third information including at least the work key using the master key into encrypted work key related information;

a multiplexer unit configured to multiplex the encrypted content, the encrypted related information, and the encrypted work key related information into multiplexed encrypted contents;

a multiplexed encrypted content transmission unit configured to transmit the multiplexed encrypted contents multiplexed by the multiplexer unit; and

an encrypted content key related information transmission unit configured to repeatedly transmit the encrypted content key related information for a predetermined time period after said multiplexed encrypted content transmitting means starts transmitting the multiplexed encrypted contents or for a time period a predetermined time period before said multiplexed encrypted content transmitting means starts transmitting the multiplexed encrypted contents or, if the receiving side has not received the encrypted content key related information, to transmit the encrypted content key related information in response to a request from the receiving side, or to transmit the encrypted content key related information via a communication network,

wherein if a plurality of security modules are correspondingly provided in receivers at the receiver side, each security module storing decrypted content key related information and being unreadable from exterior, the plurality of security modules being grouped into a plurality of groups, different work keys are used for different groups of the plurality of security modules,

each security module has a plurality of intrinsic keys for encrypting information outputted form the security module, and

the content transmission apparatus further comprises an intrinsic key related information encryption unit configured to encrypt the plurality of intrinsic keys into encrypted intrinsic key related information using the master key.

24. The content transmission apparatus as claimed in claim 2, wherein at least one of the plurality of intrinsic keys is common to other security modules.

6. A content reception apparatus that receives encrypted contents of digital broadcasting, encrypted at a transmitter side, comprising:

a memory that stores encrypted content;

a multiplexed encrypted content reception unit configured to receive a multiplexed encrypted content containing;

encrypted contents into which the contents are encrypted using a scrambling key that changes as time passes;

encrypted related information into which first information related to the contents is encrypted, the first information including at least the scrambling key, using a content key provided to each content;

encrypted content key related information into which second information related to the content key is encrypted, the second information including at least the content key, using a work key retained for a time period longer than a duration of the contents; and

encrypted work key related information into which third information related to the work key is encrypted, the third information including at least the work key, using a master key provided commonly to a receiver side,

wherein the encrypted contents, encrypted related information , encrypted content key and encrypted work key are multiplexed,

the content reception apparatus further comprising;

a multiplexed encrypted content demultiplexer unit configured to demultiplex the multiplexed encrypted content received by the multiplexed encrypted content reception unit, into the encrypted content, the encrypted related information, the encrypted content key related information and the encrypted work key related information;

a multiplexed encrypted content decryption unit configured to decrypt the encrypted work key related information using the master key to obtain the work key, the encrypted content key related information using the obtained work key to obtain the content key, the encrypted related information using the obtained content key to obtain the content key, the encrypted related information using the obtained content key to obtain the scrambling key, and the encrypted content using the obtained scrambling key to obtain the content;

a content key related information storage unit, provided with a security module storing the master key and being unreadable from exterior, the content key related information storage unit configured to store decrypted content key related information and a content identifier associated with the decrypted content key related information for identifying the content,

wherein a plurality of security modules are correspondingly provided in content reception apparatuses at the receiver side, the plurality of security modules being grouped into a plurality of groups, and different work keys are used for different groups of the plurality of security modules,

wherein each of the security modules has a plurality of intrinsic keys for encrypting information outputted from the security modules, and

the content reception apparatus further comprises a decrypted content key using one of the plurality of intrinsic keys.

8. The content reception apparatus as claimed in claim 6, further comprising an encrypted content key related information request unit that, if the encrypted content key related information is not received, requests the encrypted content key related information from the transmitter side.

11. The content reception apparatus as claimed in claim 6, further comprising a content key related information deletion unit that, in a case in which the decrypted content key related information requires more memory capacity than that which the security module can store, deletes the decrypted content key related information based on a time at which said decrypted content key related information is stored and information set by the transmitter side or the receiver side.

12. The content reception apparatus as claimed in claim 6, further comprising a content key related information output storage unit configured to output and store the decrypted content key related information stored in the security module.

13. The content reception apparatus as claimed in claim 12, further comprising a content key related information deletion unit that, in a case in which the decrypted content key related information requires more memory capacity than that which the storage unit can store, deletes the decrypted content key related information base on a time at which said decrypted content key related information is stored and information set by the transmitter side of the receiver side.

14. The content reception apparatus as claimed in claim 6, further comprising a content key related information re-encryption storing means for encrypting the decrypted content key related information stored in the security module using the master key, and outputting and storing the encrypted content key related information as re-encrypted content key related information.

15. The content reception apparatus as claimed in claim 14, further comprising a re-encrypted content key related information deletion unit that, in a case in which the re-encrypted content key related information and a content identifier for identifying a content require more memory capacity than that which the storage unit can store, deletes the re-encrypted content key related information based on a time at which the re-encrypted content key related information is stored or information set by the transmitter side or the receiver side.

16. The content reception apparatus as claimed in claim 6, further comprising a content key related information intrinsic encryption storage unit configured to store, using said intrinsic keys, the decrypted content key related information stored in the security module into an intrinsic encrypted content key related information, and output and store the intrinsic encrypted content key related information.

17. The content reception apparatus as claimed in claim 16, further comprising an intrinsic encrypted content key related information deletion unit that, in a case in which the intrinsic encrypted content key related information and a content identifier for identifying a content require more memory capacity than that which the storage unit can store, deletes the intrinsic encrypted content key related information based on a time at which the intrinsic encrypted content key related information is stored or information set by the transmitter side or the receiver side.

18. The content reception apparatus as claimed in claim 6, further comprising a storage medium handling unit configured to store re-encrypted content key related information with a corresponding encrypted content;

wherein the decrypted content key related information is re-encrypted into the re-encrypted content key related information using the master key.

20. The content reception apparatus as claimed in claim 6,

wherein the memory that store encrypted content comprises an encrypted content storage unit provided with a storing means and a storage medium handling means, that stores, in a storage medium handled by the storage medium handling means, encrypted content encrypted using the scrambling key and encryption related information related to the content including a content identifier for identifying the encrypted content;

and said content reception apparatus further comprises;

a related information input unit, wherein in a case in which, when the encrypted content stored in the storage medium is reproduced, the re-encrypted content key related information corresponding to the encrypted content is stored in at least one of the storing means and the storage medium, the related information input unit reads and inputs, in the security module, the re-encrypted content related information from the storing means or the storage medium, and inputs the encrypted related information;

a scrambling key output unit that obtains the content key by decrypting the re-encrypted content key related information using the master key, obtains the scrambling key by decrypting the encrypted related information using the content key, and outputs the scrambling key; and

an encrypted content decryption unit configured to decrypt the encrypted content stored in the storage medium using the scrambling key outputted by the scrambling key output unit.

22. The content reception apparatus as claimed in claim 6, further comprising a content key un-storing unit that, in a case in which the encrypted content is not stored during transmission of the encrypted content, does not store content key corresponding to the encrypted content.

23. The content reception apparatus as claimed in claim 6, further comprising a content key switch unit configured to switch the content key based on a time at which a content corresponding to the encrypted related information starts to be transmitted and a time at which the content is finished being transmitted.

7. A content reception apparatus that receives encrypted contents of digital broadcasting, encrypted at a transmitter side comprising:

a memory that stores encrypted content;

a multiplexed encrypted content reception unit configured to receive a multiplexed encrypted content containing;

encrypted contents into which the contents are encrypted using a scrambling key that changes as time passes;

encrypted related information into which first information related to the contents is encrypted, the first information including at least the scrambling key, using a content key provided to each content;

encrypted content key related information into which second information related to the content key is encrypted, the second information including at least the content key, using a work key retained for a time period longer than a duration of the contents; and

encrypted work key related information into which third information related to the work key is encrypted, the third information including at least the work key, using a master key provided commonly to a receiver side,

wherein the encrypted contents, encrypted related information, encrypted content key and encrypted work key are multiplexed,

the content reception apparatus further comprising;

a multiplexed encrypted content demultiplexer unit configured to demultiplex the multiplexed encrypted content received by said multiplexed encrypted content reception unit, into the encrypted content, the encrypted related information, and the encrypted work key related information;

a multiplexed encrypted content decryption unit configured to decrypt the encrypted work key related information using the master key to obtain the work key, the encrypted content key related information using the obtained work key to obtain the content key, the encrypted related information using the obtained content key to obtain the scrambling key, and the encrypted content using the obtained scrambling key to obtain the content;

a content key related information storage unit, provided with a security module storing the master key and a intrinsic key for encrypting information to be output and being unreadable from exterior, the content key related information storage unit configured to store decrypted content key related information and a content identifier associated with the decrypted contend key related information for identifying the content;

wherein a plurality of security modules are correspondingly provided in content reception apparatuses at the receiver side, the plurality of security modules being grouped into a plurality of groups, and different work keys are used for different groups of the plurality security modules, wherein each of the security modules has a plurality of intrinsic keys for encrypting information outputted from the security modules, and

the content reception apparatus further comprises a decrypted content key using one of the plurality of intrinsic keys.

9. The content reception apparatus as claimed in claim 7, wherein at least one of the intrinsic keys is set commonly to another security module.

10. The content reception apparatus as claimed in claim 7, further comprising:

an encrypted intrinsic key setting related information reception unit configured to receive encrypted intrinsic key setting related information, wherein the transmitter side encrypts a plurality of intrinsic keys into the encrypted intrinsic key setting related information; and

an encrypted intrinsic key setting related information, decryption unit configured to decrypt using the master key, the encrypted intrinsic key setting related information received by the encrypted intrinsic key setting related information reception unit.

19. The content reception apparatus as claimed in claim 7, further comprising a storage medium handling unit configured to store intrinsic encrypted content key related information with a corresponding encrypted content;

wherein the decrypted content key related information is re-encrypted into the re-encrypted content key related information using the intrinsic keys.

21. The content reception apparatus as claimed in claim 7,

wherein the memory that store encrypted content comprises:

an encrypted content storage unit provided with a storing means and a storage medium handling means, that stores, in a storage medium handled by the storage medium handling means, encrypted content encrypted using the scrambling key and encryption related information related to the content including a content identifier for identifying the encrypted content;

and said content reception apparatus further comprises;

a related information, wherein in a case in which, when the encrypted content stored in the storage medium is reproduced, the intrinsic encrypted content key related information corresponding to the encrypted content is stored in at least one of the storing means and the storage medium, the related information input unit reads and inputs, in the security module, the intrinsic encrypted content related information from the storing means or the storage medium, and inputs the encrypted related information;

a scrambling key output unit that obtains the content key by decrypting the intrinsic encrypted content key related information using the intrinsic key, obtains the scrambling key by decrypting the encrypted related information using the content key, and outputs the scrambling key; and

an encrypted content decryption unit configured to decrypt the encrypted content stored in the storage medium using the scrambling key outputted by the scrambling key output unit.