JP2009135825A - Information processing apparatus and information processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information processing apparatus capable of easily performing unified management of the same contents even when storing a plurality of data items in different formats, relating to the same contents each other. <P>SOLUTION: A computer 1 stores in a storage device 30 a content file 301, including encrypted content data text and a key ID specifying a content key for decrypting the relevant content data text, and a key management table 402, in which a content key is related to a key ID. When the storage device 30 stores therein a plurality of content files 301, whose contents are identical to one another, regardless of the data formats, a key ID 315 has the same value between such content files 301, and the content data text is encrypted by the same content key which is specified by the relevant key ID. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an information processing apparatus and an information processing method for receiving a digital television broadcast and storing the content of the broadcast.

  In recent years, personal computers capable of receiving television broadcast program data have become widespread. In such a personal computer, for example, data is transferred via a general-purpose bus such as a PCI (Peripheral Component Interconnect) bus, and the data is stored in a general-purpose medium such as an HDD (Hard Disc Drive). In order to prevent unauthorized analysis from the viewpoint of the above, it is essential that the data exchange and data storage be performed after encryption.

As a management method of encryption key information used for such encryption, an encryption key management method described in Patent Document 1 below is known. In this encryption key management method, a management file and a key file are used, the key number of the encryption key is recorded for each content in the management file, and the key number and the corresponding key data are recorded in the key file. .
JP 2005-109869 A

  However, in recent television broadcasting, there is a new operation rule (for example, “Dubbing 10”) that allows the content of a television broadcast program stored in a general-purpose medium in a computer to be copied to an external medium a plurality of times. This is being established. In order to deal with such an operation rule, it is necessary to manage a copy history of stored content in the computer. On the other hand, in such a computer, there may be a usage in which the content generated and stored first is converted into another data format. Therefore, when a plurality of pieces of content data of different data formats coexist with the same content, the complicated history of managing the copy history of the content itself while matching the history information about each of the data of the plurality of different formats. Processing is required.

  Therefore, an object of the present invention is to provide an information processing apparatus that can easily perform unified management of content even when a plurality of pieces of content information of different formats related to the same content are stored.

  An information processing apparatus according to the present invention specifies an encrypted content data body and key information for decrypting the content data body in an information processing apparatus that receives a digital television broadcast and stores the content of the broadcast. Content storage means for storing content information including key ID information, and management information storage means for storing content management information in which key information is associated with the key ID information. When a plurality of pieces of content information having the same content are stored, the plurality of pieces of content information having the same content have the same key ID information and the same key specified by the key ID information. The content data body is encrypted using information.

  An information processing method according to the present invention specifies an encrypted content data body and key information for decrypting the content data body in an information processing method for receiving a digital television broadcast and storing the content of the broadcast. A content storage step for storing content information including the key ID information in the content storage unit; and a management information storage step for storing content management information in which the key information is associated with the key ID information in the management information storage unit. In the content storage step, when a plurality of pieces of content information having the same content regardless of the data format are stored in the content storage unit, the plurality of pieces of content information having the same content are mutually connected with the key ID information. The same key information identified by the key ID information. Content data body is encrypted using, characterized in that.

  According to the information processing apparatus and the information processing method of the present invention, even when a plurality of pieces of content information of different formats related to the same content are stored, unified management of the content can be easily performed.

  Hereinafter, a preferred embodiment of an information processing apparatus according to the present invention will be described in detail with reference to the drawings. This information processing apparatus is realized, for example, as a notebook personal computer 1 as shown in FIG. The computer 1 has a function of receiving a digital television broadcast and storing the content of the broadcast.

  As shown in FIG. 1, the computer 1 communicates with a display device 20 that displays necessary information on a PCI bus 10 that is a general-purpose bus, a storage device 30 such as an HDD that is general-purpose media, and an external device (not shown). , A copyright protection device 50 having a function of managing parameters used for data encryption, and a control device 60 for controlling the computer are respectively connected.

  The control device 60 is provided, for example, in the form of a motherboard, and includes an oscillator 61 for setting system time and synchronizing, an input / output interface 62 for exchanging information with the outside of the control device, A power supply 63 that supplies power, a system memory such as a RAM 64, an EEPROM 65, and a BIOS ROM 66, and an MPU 67 that executes a program using the RAM 64 and controls the entire information processing apparatus. As one of programs executed by the MPU, there is content processing software 100 for handling television broadcast program data.

  As shown in FIG. 2, the copyright protection device 50 includes an oscillator 51 for synchronization, an input / output interface 52 for exchanging information with the outside, a power supply 53 for supplying power, a system memory such as a RAM 54 and a FLASH ROM 55, and the like. The RAM 54 is used to execute a program and control the entire copyright protection device 50 including control of communication functions. Here, the copyright protection device 50 exists as a tuner unit that receives television broadcast program data that is broadcast after being encrypted.

  As shown in FIG. 1 again, the copyright protection device 50 and the content processing software 100 (that is, the control device 60) are connected via the PCI bus 10, which is a general-purpose bus. Therefore, the copyright protection device 50 and the content processing software 100 execute an authentication process when exchanging various important data including the television broadcast program data via the PCI bus 10. After the authentication process, for example, a session key generated from the authentication process is used for encryption of various important data. For example, the copyright protection device 50 decrypts the received television broadcast program data, re-encrypts the television broadcast program data using a randomly generated random number as an encryption key, and supplies it to the content processing software 100. However, the encryption with the session key is also performed when the encryption key is transferred. The content processing software 100 uses the session key to decrypt the encryption key itself, and uses the encryption key to decrypt the television broadcast program data.

  The content processing software 100 can also encrypt television broadcast program data and store the encrypted data as a content file (content information) 301 in the storage device 30 that is a general-purpose medium. At this time, an encryption key for decrypting the content file 301 is described in a key management table (content management information) 402 that is also stored in the storage device 30. The key management table 402 is a table having a plurality of entries for storing encryption keys. When the content processing software 100 stores a new content file 301 in the storage device 30, the key management table 402 is copyrighted. Transfer to the protection device 50 and request registration of the encryption key (used for re-encryption) in the key management table 402.

  The key management table 402 is encrypted by the copyright protection device 50, and is stored in the storage device 30 in a state where the encryption is performed. When registering a new encryption key in the key management table 402, the copyright protection apparatus 50 once decrypts the encryption, holds the encryption key in the empty entry, re-encrypts it, and performs the content processing software 100. Return to The content processing software 100 stores the returned key management table 402 in the storage device 30.

  When reproducing the content file 301, the content processing software 100 transfers the key management table 402 to the copyright protection device 50 together with information indicating which content file 301 is to be reproduced. The copyright protection device 50 decrypts the transferred key management table 402 using predetermined parameters, takes out the encryption key corresponding to the target content file 301, and performs encryption using the session key. After that, the content is returned to the content processing software 100. The content processing software 100 uses this returned encryption key to decrypt the content data body of the content file 301.

  As described above, the copyright protection device 50 manages the encryption of the television broadcast program data transmitted / received via the PCI bus 10 that is a general-purpose bus and stored in the storage device 30 that is a general-purpose medium. Analysis is prevented.

  Next, as shown in FIG. 3, the content file 301 stored in the storage device 30 has a structure in which a content header 313 is added to the encrypted content data main body 311. The header 313 includes a key ID 315 as information for specifying a content key for decrypting the content data body 311. The header 313 and the content data body 311 are encrypted with different keys.

  Here, in the computer 1, for example, two content files for the same content are obtained by format conversion of the stored content file 301 (for example, format conversion from MEPG2 TS data to H.264 data). 301 (conversion source file and post-conversion file) may exist. In such a case, in the two files, the content data body 311 can be decrypted using the same content key, and the same information is described in the key ID 315 of the header 313. That is, the content files 301 showing the same content have the same content key and the same key ID 315 even if the formats are different. As described above, a series of content files 301 indicating the same content regardless of the format may be referred to as “same content file group” in the following description.

  As shown in FIG. 4, the key management table 402 stored in the storage device 30 is associated with a key ID 415, a reference data number (existence number information) 417, a copy possible number 419, and a content key 421. It is a table that was made. The key ID 415 corresponds to the key ID 315 of the content file 301 (FIG. 3). The content key 421 is a value of an encryption key that actually encrypts the content data body 311 of the content file 301. That is, for example, the content data body 311 of the content file 301 in which “128” is described as the key ID 315 has a key ID 415 = “128” on the key management table 402 (in the case of the example of FIG. It is encrypted with the content key 421 corresponding to (lower line) and can be decrypted with the content key 421.

  The reference data number 417 in the key management table 402 is information indicating how many content files 301 to which a key ID 315 having the same value as a certain key ID 415 is attached exist in the storage device 30. For example, if there are two content files 301 having the same key ID 315 as a certain key ID 415 in the storage device 30, “2” is described as the reference data number 417. As described above, as a case where the number of reference data 417 is plural, for example, there are cases where plural files belong to the “same content file group” by format conversion as described above. Further, the file is not limited to a different format, and files of the same content in exactly the same format may be counted as the reference data number 417 as “same content file group”. The reference data number 417 increases when a copy of the content file 301 having the corresponding key ID 315 is created in the computer 1 and decreases when the content file 301 is deleted.

  Further, the above-mentioned number of possible copies 419 in the key management table 402 is information indicating how many times the content file 301 corresponding to a certain key ID 415 can be copied to a medium outside the computer 1 (for example, DVD medium). It is. This possible copy count 419 is subtracted and updated every time any content file 301 corresponding to the key ID 415 is copied to an external medium. That is, if any one of the plurality of files in the “same content file group” is copied to the external medium once, the number of times the key ID can be copied 419 corresponding to the “same content file group” is 1. Only the subtraction is updated. Therefore, the number of possible copies 419 indicates how many times the content files 301 of the “same content file group” corresponding to a certain key ID 415 can be copied in total. When the number of possible copies 419 is “1”, it means that the content file 301 can only be “moved” for the external medium.

  Processing performed by the content processing software 100 when performing management using the key ID 315 described in the key management table 402 and the header 313 of the content file 301 will be described.

(Content accumulation processing)
With reference to FIG. 5, processing for storing and accumulating content in the storage device 30 will be described. First, the content processing software 100 opens the content file 301 to store the content (S501). In this process, a vacant number (unused key ID) in which a content key can be registered is found from the key management table 402, and a header 313 to which the vacant number key ID 315 is attached is generated. Thereafter, the content processing software 100 performs a process of encrypting and writing the content data in the opened file (S502). Thereafter, the process S502 is continued until it is determined in the determination process (S503) whether or not to continue the write process S502, and the content data body 311 is generated.

  After that, when it is determined in S503 that the writing process is to be terminated, the content processing software 100 writes the number of possible copies 419 in the row of the corresponding key ID 315 in the key management table 402 (S504). The copyable number of times 419 written here is obtained by interpreting the right protection information related to the content to be saved by the content processing software 100. For example, in the case of content to which the “dubbing 10” rule is applied, the number of times that copying is possible 419 = “10” is described. Thereafter, the content processing software 100 closes the content file 301 (S505) and ends the processing.

(Format conversion process)
Next, processing for converting the data format of the content file 301 stored / stored in the storage device 30 will be described with reference to FIG. First, the content processing software 100 opens the conversion source content file 301 (S601). Next, the content processing software 100 newly opens the conversion destination content file 301 using the file handler opened in the above processing S601 (S602). Here, a header 313 in which the same key ID 315 as that of the conversion source content file 301 is described is generated. Next, the content processing software 100 reads the content data body 311 from the opened conversion source content file 301 and decrypts it using the content key 421 corresponding to the key ID 315 (S603).

  Next, the content processing software 100 converts the data read in step S603 into a desired format and encrypts it (S604). This encryption is performed using the content key 421 corresponding to the same key ID 315 as the content file 301 of the conversion source. That is, the content data body 311 at the conversion destination is encrypted using the same content key as the content key obtained by decrypting the content data body 311 at the conversion source. Then, the content processing software 100 writes the content data converted / encrypted in step S604 into the content data body 311 of the opened conversion destination content file 301 (S605).

  Thereafter, the processes S603 to S605 are continued until it is determined in the determination process (S606) whether or not to continue the processes S603 to S605, and the content data body 311 of the conversion destination content file 301 is generated. After that, the content processing software 100 edits the key management table 402, and updates the reference data number 417 of the key ID 415 corresponding to the key ID 315 of the conversion source content file 301 by 1 (S607). Thereafter, the content processing software 100 closes the conversion destination content file 301 (S608), closes the conversion source content file 301 (S609), and ends the processing. With the above processing, the conversion-destination content file 301 having the same key ID 315 and the content data body 311 can be decrypted with the same content key, and the conversion-destination content file 310 having a different data format is created. .

(Content file deletion process)
Next, processing for deleting the content file 301 stored / stored in the storage device 30 will be described with reference to FIG. First, the content processing software 100 acquires the key ID 315 described in the header 313 of the content file 301 related to deletion (S701). Then, the content processing software 100 refers to the key management table 402, acquires the reference data number 417 of the key ID 415 corresponding to the key ID acquired in the above-described processing S701, and uses the value of the reference data number 417 to perform the subsequent processing. Processing branches (S702).

  That is, in S702, when the value of the acquired reference data number 417 is “1”, the “same content file group” corresponding to the key ID 415 is only the content file 301 related to deletion. That is, it means that the content key 421 corresponding to the key ID 415 is not required for the content file 301 other than the content file 301 related to deletion. Therefore, in this case, the content processing software 100 performs the invalidation processing of the content key 421 (S703). As the invalidation process, for example, a process of overwriting the content key 421 with a random number is employed.

  On the other hand, when the value of the obtained reference data number 417 is “2” or more in S702, the “same content file group” corresponding to the key ID 415 includes a plurality of content files 301. That is, it means that the content key 421 corresponding to the key ID 415 is required for the content file 301 other than the content file 301 related to deletion. Therefore, in this case, the content processing software 100 does not perform the revocation processing of the content key 421, and subtracts and updates the reference data number 417 by 1 (S704). Since the key management table 402 is stored in the storage device 30, it is necessary to re-encrypt with a key different from the encryption key before the subtraction every time the process S704 is executed.

  As described above, according to the computer 1, the content file 301 (same content file group) indicating the same content is all described with the same key ID in the header 313 regardless of the data format, and the content data body Can be decrypted with the same content key. Therefore, for example, an MPEG2 TS format file and an H.264 file for the same content. When files in H.264 format coexist, even if any file is copied to an external medium, the copyable number of times corresponding to the content is subtracted and updated. As described above, according to the computer 1, even when a plurality of files of different formats exist for one content by the format conversion process, the number of times that the one content can be copied is centrally managed. In addition, with such a management method, it is possible to easily realize a specification that can handle the “dubbing 10” rule that requires copy history management for each content.

It is a block diagram which shows the computer as one Embodiment of the information processing apparatus which concerns on this invention. It is a block diagram which shows the copyright protection apparatus shown by FIG. It is a figure which shows the structure of the content file preserve | saved in the computer of FIG. It is a figure which shows the key management table used for content management in the computer of FIG. 2 is a flowchart showing content storage processing performed by content processing software in the computer of FIG. 1. 2 is a flowchart showing format conversion processing performed by content processing software in the computer of FIG. 1. 2 is a flowchart showing content file deletion processing performed by content processing software in the computer of FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Computer (information processing apparatus), 30 ... Memory | storage device (content storage means, management information storage means), 100 ... Content processing software (format conversion means), 301 ... Content file (content information), 311 ... Content data main body 315, 415 ... key ID (key ID information), 402 ... key management table (content management information), 417 ... number of reference data (existence number information), 419 ... number of copies allowed, 421 ... content key (key information).

Claims (5)

In an information processing apparatus that receives a digital television broadcast and stores the content of the broadcast,
Content storage means for storing content information including encrypted content data body and key ID information for specifying key information for decrypting the content data body;
Management information storage means for storing content management information in which the key information is associated with the key ID information,
When a plurality of pieces of content information having the same content regardless of the data format are stored in the content storage unit,
The plurality of pieces of content information having the same content have the same key ID information, and the content data body is encrypted using the same key information specified by the key ID information.
An information processing apparatus characterized by that. The content management information includes
The information processing apparatus according to claim 1, wherein presence information indicating the number of contents information to which the key ID information is attached is further recorded in association with the key ID information. Format conversion means for converting the format of the content information stored in the content storage means;
The format conversion means includes
While generating the converted content information including the same key ID information as the content information of the conversion source, and the converted content data body encrypted using the key information specified by the key ID information ,
The information processing apparatus according to claim 2, wherein the existence number information associated with the key ID information of the content management information is updated. The content management information includes
4. The copyable number information indicating how many times the content information to which the key ID information is attached can be copied in total in association with the key ID information is further recorded. The information processing apparatus described in 1. In an information processing method for receiving a digital television broadcast and storing the content of the broadcast,
A content storage step of storing content information including encrypted content data body and key ID information for specifying key information for decrypting the content data body in a content storage unit;
A management information storage step of storing, in a management information storage unit, content management information in which the key information is associated with the key ID information,
In the content storage step, when a plurality of pieces of content information having the same content are stored in the content storage unit regardless of the data format,
In a plurality of pieces of content information having the same content, the key ID information is mutually the same, and the content data body is encrypted using the same key information specified by the key ID information.
An information processing method characterized by the above.

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