JP2008294734A - Content management system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the number of digits of related information to be inputted into a terminal device to decode the encrypted content. <P>SOLUTION: A content decoder is a terminal having an inherent information outputting portion for outputting information inherent to a device, a key position inputting portion for inputting a key position inherent to a device, a bunch-of-key inputting portion for inputting a bunch of keys, and a decoding key acquiring portion which extracts encryption information determined by the key position from the bunch-of-key information and performs an operation inherent to a device on the encryption information to acquire a content decoding key. The content decoding key is encrypted by a terminal key which is different from terminal to terminal, and the bundle of keys for encrypted information of all the terminals is distributed in advance together with content. To a terminal which requests for a license, a key position for the terminal in the bundle of keys is returned as a license based on the information inherent to the terminal which is sent from the terminal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a content management system, and more particularly to a content management system including a content decrypting device, a license issuing device, and a content creating device for preventing unauthorized use of copyright-protected content.

2. Description of the Related Art Recently, in a car navigation system that provides traffic guidance information to a user (hereinafter simply referred to as a car navigation system), a device that uses an HDD (Hard Disk Drive) (HDD type car navigation system) has attracted attention as a recording device that records map data. Yes.
The HDD type car navigation system needs to update the data in the car navigation system to the latest in order to provide appropriate traffic information to the user when the map data becomes old due to construction or removal of roads or buildings. In the case of a conventional DVD type car navigation system, a DVD on which map data is recorded can be sold to a user, and the user can easily update it by replacing it with an old disk. On the other hand, in the case of the HDD type car navigation system, it is difficult for the user to replace the HDD itself, so the map data must be copied to the HDD by some means. Copying to the HDD is usually performed by inserting a DVD on which map data is recorded into the car navigation system and copying it to the HDD. Alternatively, it is performed by connecting a PC (Personal Computer) on which map data is recorded and a car navigation system, and copying from the PC to the HDD of the car navigation system.

  As described above, when the map data is updated by the HDD type car navigation system, unlike the DVD type car navigation system, the map data is copied. Therefore, from the viewpoint of protecting the copyright owner of the map data, some measures are required for restricting unauthorized copying to the HDD. Since such problems are not limited to car navigation systems, many techniques have been proposed and put into practical use as means for preventing unauthorized copying to a terminal having a recording device such as an HDD (hereinafter referred to as a terminal). It is provided.

  As a means to prevent unauthorized copying of data, in the old days, when copying data, the user was forced to enter a character string commonly referred to as a serial number, and the entered serial number was subject to certain mathematical laws. There is a method of permitting copying only when the condition is satisfied. However, this method has a problem that once a serial number can be obtained, it can be copied to a plurality of terminals many times using the same number.

  In recent years, a method of restricting copying by encrypting and distributing data and restricting distribution of the decryption key has been used. This decryption key is distributed by being included in information generally called a license, and distributed in a form that cannot be easily extracted by a malicious person. This license is distributed to the terminal by the following procedure, for example. First, terminal-specific information (hereinafter referred to as terminal-specific information) such as an HDD ID is sent from a terminal to a device that issues a license (hereinafter referred to as a license issuing device). The license issuing device encrypts the data decryption key and other information using the received terminal-specific information as a key to create information called a license, and returns the information to the terminal. As a result, only the terminal that has requested the license can extract the data decryption key by decrypting the license using its own terminal-specific information. This type of technology is disclosed in many documents in addition to Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-252752), and in particular, it is used for online distribution of music data that has been popular recently.

As means for transmitting and receiving such a license, a communication network using IP (Internet Protocol) is usually used. However, since not all terminals necessarily have an IP communication function, some means that do not depend on IP communication have been proposed. For example, the technique described in Patent Document 2 (Japanese Patent Laid-Open No. 2005-227809) discloses a technique in which information corresponding to a license is stored in a non-contact data carrier and read on the terminal side. Further, the technique described in Patent Document 3 (Japanese Patent Application Laid-Open No. 2006-121413) discloses a technique for printing information corresponding to a license on paper and reading the information with a scanner installed in a terminal.
In addition, if there is an interface such as USB (Universal Serial Bus) on the terminal side, it is also possible to connect a flash memory medium such as a USB memory, which has become popular in recent years, and send and receive licenses.

JP 2004-252752 A JP 2005-227809 A JP 2006-121413 A

  However, the above technique has a problem that IP communication or a special device must be used. In the case of a car navigation system, all models do not necessarily have an IP communication function, and usually do not include a reader or scanner of a non-contact data carrier.

In addition, when using a medium such as a flash memory such as a USB memory that has become widespread in recent years, at least the following procedures (1) to (3) are required. That is, (1) a USB memory is connected to a car navigation system and terminal specific information is recorded. (2) The USB memory is removed from the car navigation system, connected to the PC, terminal specific information is transmitted to the license issuing device, the license is received and recorded in the USB memory. (3) Remove the USB memory from the PC, connect to the car navigation system, and write the license to the car navigation system.
This procedure is not easy for users who are not familiar with information communication technology. Since car navigation users have a wide range of drivers from young people to elderly people, it is desirable to prevent unauthorized copying by a simple method that can be used regardless of generation.

  Therefore, it is conceivable to input / output terminal-specific information and a license using an input / output device of a touch panel type liquid crystal screen equipped in most car navigation systems. (1) The terminal specific information displayed on the screen is copied to the memo, (2) The terminal specific information is transmitted to the license issuing device via the PC, and the returned license is copied to the memo. (3) The license is displayed on the screen. It is desirable from the viewpoint of ease of operation if a procedure of inputting to the input is possible.

  When such a method is realized, since the terminal-specific information and the license are manually input by the person, the shorter the number of digits, the better. In this regard, when the map data is encrypted with a 128-bit common key, which is the minimum key length of recent encryption technology, the license including the decryption key has a minimum length of 128 bits, and one character 6 Even if conversion is performed using bits (corresponding to Base64 encoding), 22 characters are required. In this case, the number of digits to be input by operating the touch panel type liquid crystal screen is too long.

  An object of the present invention is to reduce the number of digits for inputting related information while maintaining normal encryption strength in an apparatus for inputting related information for decrypting content.

  The present invention encrypts a content decryption key with a different terminal key for each terminal, distributes a key bundle in which the encrypted information for all terminals is bundled together with the content in advance, and Based on the terminal-specific information sent from the terminal, the key position for the terminal in the key ring is returned as a license. As a result, it is not necessary to include the encryption key in the license transmitted to the terminal, and the number of digits of the license can be reduced.

According to a preferred example, the content decryption apparatus according to the present invention is a terminal that decrypts and uses content, and includes a key position input unit that inputs a key position unique to the apparatus acquired from the outside, and a key bundle. An input key ring input unit, and a decryption key acquisition unit that extracts encryption information determined by a key position from the key ring information, and acquires a decryption key of the content by performing a device-specific operation on the encryption information; It is configured as a content decrypting device.
The present invention is also grasped as a content decryption processing method or management method.

  According to a preferred content management system example, the content decrypting device is connected to a content creating device and a license issuing device. The content creation device functions as a device that distributes the key bundle to a number of content decryption devices, and records the key position and the calculation method applied to the content decryption key for the unique information for each content decryption device. A key ring creation table recording unit, and a key ring output unit that outputs a key ring that is created by storing encryption information obtained by applying the calculation method to a decryption key at a position indicated by the key position . In addition, the license issuing device functions as a device that notifies the content decryption device of the key position, a unique information input unit that inputs unique information for each content decryption device, and a key that holds the key position in the key bundle for the unique information A position table recording unit; and a key position output unit that outputs a key position.

  According to the present invention, it is possible to reduce the number of digits of related information input to use a key for decrypting content while maintaining a normal encryption strength.

[Example 1]
Hereinafter, Example 1 is demonstrated using FIGS. 1-12.
This embodiment assumes a map data update system using a DVD. That is, a user who purchases a DVD in which content including encrypted map data is recorded acquires a license for the DVD, and rewrites the map data on the HDD by inputting the acquired license on the car navigation screen. .

FIG. 1 shows an overall configuration diagram of a map data update system.
This map data update system is configured by connecting a content decrypting device 100, a content creating device 200, and a license issuing device 300 via communication media 401 to 403.
The content decryption apparatus 100 records a content input unit 101 that inputs content recorded on a DVD, a specific information output unit 120 that outputs terminal-specific information, a key position input unit 130 that inputs a key position, and a terminal-specific key. A terminal key recording unit 140, a key bundle analyzing unit 150 for extracting a data key for decoding the map data from the key bundle, a map data decoding unit 160 for decoding the map data using the extracted data key, and the map data It has a map data recording unit 170 for recording.

  In this example, the unique information output unit 120 and the key position input unit 130 are configured using an input display device having a touch screen. The user can select and input information by touching the screen. In addition, the map data decryption unit 160 and the key ring analysis unit 150 each have a function realized by a CPU (processor) executing a predetermined program.

  One characteristic here is that the number of input digits of related information for decryption is reduced by inputting the key position from the key position input unit 130. That is, the number of digits in the key position is considerably smaller than the number of digits in the data key for decrypting the content according to the prior art. Since it is preferable to change the key position for each terminal (content decryption apparatus) to which content is distributed, it is sufficient that the number of different key positions is about the number of terminals assumed. For example, assuming that there are about tens of millions of car navigation systems equipped with content decoding devices that handle map data nationwide (that is, less than 100 million units), prepare the number of key positions corresponding to that number. Therefore, if the key position is 8 digits, it can be handled. Compared to a 128-bit common key (ie, 22 digits) for encrypting and decrypting car navigation content that is currently in practical use, approximately one third of the number of digits is sufficient. Become.

  The content creation device 200 includes a data key recording unit 210 that records a data key for encrypting map data, a map data encryption unit 220 that encrypts map data using the data key, and a relationship between the terminal key and the key position. A terminal key table recording unit 230 that records a terminal key table to be shown, a key bundle generation unit 240 that generates a key bundle to be attached to map data, a content output unit 250 that outputs map data and a key bundle, a terminal key table and a terminal to be described later A management table creation unit 260 that creates an ID table, a terminal information recording unit 280 that indicates the relationship between the terminal ID and the terminal key, and a map data recording unit 290 that records map data are configured. Here, each function of the map data plan og unit 220, the key ring generation unit 240, and the management table creation unit 260 is realized by a predetermined program being executed by a CPU (processor).

  The license issuing device 300 includes a terminal ID table recording unit 310 that records a terminal ID table indicating a relationship between a terminal ID and a key position, a specific information input unit 320 that inputs terminal specific information, and the input terminal specific information and terminal ID table. To a key position search unit 330 for specifying the key position for the terminal, and a key position output unit 340 for outputting the specified key position. Here, the function of the key position search unit 330 is realized by executing a predetermined program by a CPU (processor).

The content created by the content creation device 200 is distributed to the content decryption device 100 via the communication medium 401. The communication medium 401 may be a communication network or a recording medium such as a DVD. Here, it is assumed that it is distributed by DVD.
The communication medium 402 that connects the content decrypting device 100 and the license issuing device 300 may be a communication network that directly connects the content decrypting device 100 and the license issuing device 300, or may be connected via a communicable PC. Oral transmission by telephone or FAX may be used.
Further, the communication medium 403 connecting the content creation apparatus 200 and the license issuing apparatus 300 may be a communication network or a recording medium such as a DVD. Here, it is assumed that they are connected via a communication network.

FIG. 2 shows the configuration of various management information used in this embodiment.
(A) The terminal information recorded in the terminal information recording unit 280 includes a terminal ID 281 that is terminal specific information and a terminal key 282 of the terminal indicated by the terminal ID 281. The terminal key 282 is a key used for encrypting the data key used when encrypting the map data. Since this terminal key 282 is different for each terminal, it is necessary for the number of terminals.
(B) The terminal key table recorded in the terminal key table recording unit 230 includes a terminal key 231 and a key position 232. The key position 232 is information indicating the position of each key included in the terminal key ring. This key position is randomly determined by a random number. For example, in the content creation device 200, when a key bundle consisting of a plurality of n terminal keys is added to the content, the key position of the terminal key DK1 indicates the second position in the key bundle as shown in FIG. Yes.

(C) The terminal ID information recorded in the terminal ID table recording unit 310 includes a terminal ID 321 and a key position 322. For example, in the content decrypting apparatus 100 of the terminal whose terminal ID is “A0000001”, the key position is the second, and “2” is input from the key position input unit 130.
In these pieces of management information, the terminal information recording unit 280 is a constant value regardless of the content. On the other hand, in the terminal key table 230 and the terminal ID table 320, the values of the key positions 232 and 322 change according to the content.

FIG. 3 shows a configuration of content created by the content creation device 200.
The content recorded on the DVD 500 is composed of encrypted map data 501 and a key bundle 502 made up of a large number of key bundles. Also, a content ID 503 for identifying the content is given to the DVD 500. The content ID 503 may be recorded on the DVD 500 itself, or what is described on paper may be attached to the DVD 500.

The content processing operation will be described below.
FIG. 4 shows content creation processing in the content creation device 200.
First, the management table creation unit 260 creates a terminal key table 230 and a terminal ID table 310 for each version of map data (S201). This process will be described in detail later. The terminal ID table 310 may be transmitted to the license issuing device 300 via the communication medium 403, or recorded in the content creation device 200, and the license issuing device 300 transmits via the communication medium 403 as necessary. You may make it refer to this.

  Next, the map data encryption unit 220 encrypts the map data recorded in the map data recording unit 290 with the data key recorded in the data key recording unit 210 (S202). Next, the key ring generation unit 240 creates a key ring for decrypting the map data (S203). This process will be described in detail later. Finally, the content output unit 250 combines the map data encrypted in S202 and the key ring created in S203 and writes the combined data to the DVD 500 (S204).

FIG. 5 shows details of the processing (S201) of the management table creation unit 260.
This process is a process for determining the arrangement of the key positions. In FIG. 5, N is a constant indicating the number of terminals, I, J, and M are integer variables of 1 to N, and Random () is a function that generates a positive integer random number value less than or equal to the integer specified by the argument. is there. KEYLOC () is an array variable having N elements and is a value stored in the key position 232 of the terminal key table 230 and the key position 322 of the terminal ID table 320.

Under the above settings, first, the array KEYLOC () is initialized to 0 (S261). Subsequent S262, S263, S264, and S265 indicate processing for sequentially storing integer values from 1 to N for KEYLOC (J). Here, J is an integer value determined at random within the range of 1 to N, and this determination of J is made as follows. That is, first, a random number is set to M (S266). Subsequent processing from S267 to S271 indicates processing for searching for a place where KEYLOC () is 0, starting from KEYLOC (M).
Through the above processing, integer values from 1 to N are randomly stored in the array KEYLOC (). Finally, a terminal key table 230 and a terminal ID table 310 are created from the created array KEYLOC () and terminal information 280. This is done by a process similar to general table join and projection (S272).

FIG. 6 shows details of the processing (S203) of the key ring generation unit 240.
In FIG. 6, N is the number of terminals, I and J are integer variables of 1 to N, K is a data key recorded in the data key recording unit 210, and DK is a variable for storing a terminal key. The array KEYS () is an array variable with N elements, and this is a key ring. DEVKEY and KEYLOC mean the terminal key 231 and the key position 232 in the terminal key table 230, respectively. Under the above settings, the array KEYS () is first initialized to 0. Subsequent S242, S243, and S247 are iterative processes from 1 to N for I. For each I, first, the key position stored in the I-th row of the terminal key table 230 is stored in J (S244). Next, the terminal key stored in the I-th row of the terminal key table 230 is stored in the DK (S245). Then, the value obtained by encrypting the data key K with the key DK is stored in the J-th position of the key ring (S246). Through the above processing, information obtained by encrypting the data key K for decrypting the map data with the terminal key DEVKEY () of each terminal, that is, a key bundle, is stored in the array KEYS ().
For the content created in this way, the content decryption apparatus 100 confirms the terminal-specific information in order to obtain the key position for decrypting the content.

FIG. 7 shows an example of a screen output by the unique information output unit 120 in the content decrypting apparatus 100.
A screen 121 shows an example of a menu screen for operating a car navigation, and there is a button 122 for displaying unique information. By operating the button 122, a transition is made to a screen 123 that displays a terminal ID 124 that is terminal-specific information. By operating the button 125, the screen 123 is erased and the screen transitions to the screen 121. This screen is an example, and the screen displayed by the unique information output unit 120 may be anything as long as the terminal ID 124 can be confirmed.
The terminal ID 124 confirmed in this way is transmitted to the license issuing device 300.

FIG. 8 shows an example of a screen created by the unique information input unit 320 of the license issuing device 300.
This screen allows the user to confirm a license for decoding the map data. In this example, the license is a key position.
When the unique information input unit 320 is, for example, a touch-type display input device or a display input device, and a user notifies fixed information by telephone or FAX, an operator who operates the license issuing device 300 displays and inputs the terminal unique information. Enter using the device. Note that this screen may be displayed on the PC by accessing the license issuing apparatus 300 from a PC having a WWW (World Wide Web) browser function. In this case, it is assumed that the user performs screen display by transmitting terminal-specific information from the home PC.

  The screen 331 shown in FIG. 8 includes a column 332 for inputting a terminal ID, a column 333 for inputting a content ID attached to the DVD 500, and a button 334 for issuing a license. After inputting the terminal ID and the content ID, the screen transitions to the screen 351 by operating the button 334. The screen 351 includes a field 352 for displaying a license for the input terminal ID and content ID, and a button 353 for closing the screen 351. “00000002” displayed in the license display field 352 indicates the key position for the terminal ID “A0000001”.

FIG. 9 shows a processing flow of the license issuing apparatus 300 for the above screen.
First, the unique information input unit 320 receives the terminal ID and the content ID from the screen 331 (S301). Next, the key position search unit 330 specifies a key position corresponding to the input terminal ID and content ID (S302). This process is performed by referring to the terminal ID table 320 corresponding to the input content ID and searching for the key position 322 corresponding to the input terminal ID. Finally, the key position output unit 340 displays the specified key position on the screen 332 (S303).
With the above processing, the key position for decrypting the map data is confirmed.

Finally, the map data decrypting process in the content decrypting apparatus 100 after acquiring the content and the key position will be described.
FIG. 10 shows the screen and appearance of the content decryption apparatus 100. An example of a DVD drive 100 ′ for inserting a DVD 500 for recording content and a screen 131 for inputting a key position is shown, and the screen 131 is displayed by inserting the DVD 500 into the DVD drive 100 ′. The screen 131 includes a column 132 for inputting a key position and a button 133 for closing the screen 131.

FIG. 11 shows a processing operation flow of the content decryption apparatus 100 after the button 133 is operated.
First, the content input unit 110 reads content recorded on the DVD 500 (S101). Next, the key position input unit 130 inputs a license including the key position from the screen 131 (S102). In this example, the terminal key position in the terminal ID “A0000001” is “00000002” of 8 digits.
Next, the key ring analysis unit 150 is a data key for decrypting the map data from the input key position, the key ring assigned to the content, and the terminal key recorded in the terminal key recording unit 140. Is extracted (S103). This process will be described later. Finally, the map data decryption unit 160 decrypts the map data using the extracted data key and records it in the map data recording unit 170 (S104).

FIG. 12 shows details of the processing (S103) of the key ring analysis unit 150.
In this figure, LOC is the key position input in S102, E is the LOC-th information in the key ring, DK is the terminal key, K is the data key for decrypting the map data, Decrypt is the first argument and the second argument This function decrypts with the key specified in. Under the above settings, first, the LOC-th encryption information is stored in E (S151). Next, the cryptographic information E is decrypted using the terminal key stored in the terminal key recording unit 140 (S152). By decrypting in this way, the data key K can be acquired. Through the above processing, the content decrypting apparatus 100 decrypts the map data.

  As described above, according to the first embodiment, the license issuing device manages the relationship between the terminal ID and the key position in the terminal ID table, and the content decrypting device inputs the key position acquired from the license issuing device. The number of digits of the data key for decrypting the content (for example, 22 digits) is made the same as before, and the key position of the terminal key used for data key encryption is specified (in this example, 8 digits) The data key for decrypting the content can be acquired and used. For this reason, even if the same conventional license (22-digit data key) is used, it is possible to reduce the number of digits of information input by the content decrypting apparatus while ensuring the same encryption strength for the content. .

  The number of digits of information input to the content decryption device (information on the key position of the terminal key used for encrypting the data key) by the user is small and the third party's brute force attack is difficult. Although 8 digits are appropriate, 6 digits or 4 digits may be used in order to reduce the input burden on the user. Also, the number of digits may be increased to 10 digits or 12 digits in order to increase the security against third party brute force attacks. However, if the number of digits of information input by the user to the content decrypting apparatus (information on the key position of the terminal key used for encrypting the data key) is smaller than the number of digits of the data key for decrypting the content, It is possible to reduce the number of digits of information input by the content decrypting apparatus while ensuring at least the encryption strength for the content as before.

[Example 2]
Next, Example 2 will be described with reference to FIGS. 13 and 14.
This embodiment is a system that uses an HDD for a car navigation system, and is an example of an HDD replacement system in which only a HDD device is replaced by a dealer or a car navigation maker (hereinafter referred to as a maker or the like) due to a failure of the HDD. In this embodiment, the encrypted map data is stored in the HDD device and shipped to a manufacturer or the like. The manufacturer or the like takes out the HDD device of the broken car navigation system, replaces it with a new HDD device, and inputs the license on the screen of the car navigation system so that the map data on the HDD can be used.

FIG. 13 illustrates the overall configuration of the HDD replacement system according to the second embodiment.
The HDD exchange system according to the second embodiment includes a content decrypting device 700, a content creating device 200, a license issuing device 300, and a content recording device 600.
Compared with the content decryption device 100 in the first embodiment, the content decryption device 700 includes a data key recording unit 710 instead of the update data recording unit 170, and the content recording device 600 includes an HDD device including the recording unit 601. The point used is different. The configuration of the other parts of the content decrypting device 700 and the configuration of the content creating device 200, the license issuing device 300, etc. are the same as in the first embodiment.

Next, a process for replacing the HDD will be described.
The processing for creating content in the content creation device 200 is the same as in the first embodiment. The created content is recorded in the content recording unit 601 in the content recording device 600. In this recording process, the content creation device 200 and the content recording device 600 may be directly connected and recorded. Alternatively, the DVD 500 created by the content creation device 200 may be inserted into a general device such as a PC, and the PC and the content recording device 600 may be connected and recorded.
The content recording device 600 that has recorded the content is sent to a manufacturer or the like, and the manufacturer that has received the content recording device 600 can use the map data recorded in the content recording unit 601 of the received content recording device 600. The key position is acquired from the license issuing device 300. The flow of this process is the same as that shown in FIGS. 7, 8, and 9 in the first embodiment.

  An operator such as a manufacturer removes the old content recording device 600 from the content decrypting device 700, replaces it with the received content recording device 600, and inputs the acquired key position to the content decrypting device 700. The screen 131 is the same as the screen of FIG. 10 in the first embodiment, and includes a column 132 for inputting a key position and a button 133 for closing the screen 131. The screen 131 is displayed after replacing the HDD.

FIG. 14 shows a processing operation flow of the content decryption apparatus 700 after the button 133 is operated.
First, the key ring recorded in the content recording unit 601 is read via the content input unit 110 (S601). Next, the key position input unit 130 receives an input of a license including the key position from the screen 131 (S602). Next, the key ring analysis unit 150 is a data key for decrypting the map data from the input key position, the key ring assigned to the content, and the terminal key recorded in the terminal key recording unit 140. Is extracted (S603). The process of S603 is the same as the process shown in FIG. Finally, the key ring analysis unit 150 records the extracted data key in the data key recording unit 710 (S604).

  As a result of the above processing, the data key is recorded in the data key recording unit 710, so that the map data recorded in the content recording unit 601 can be decrypted and used as appropriate. Note that the map data may be decrypted using the recorded data key after the execution of step S604. Alternatively, when there is an access request to map data from an application program of car navigation, only necessary data may be decrypted.

  The present invention can also be used when it is necessary to issue a license for using content to a device that is not connected to a network. In addition to car navigation systems, home appliances, outdoor display devices, etc. It can also be applied to devices where network connection is not widespread.

The whole block diagram of the map data update system in one Example (Example 1). The figure which shows the structure of the various management information used in a map data update system. The figure which shows the structure of a content. 5 is a flowchart showing content creation processing in the content creation device 200. The flowchart which shows the detail of a process of a management table preparation part. The flowchart which shows the detail of a process of a key ring production part. The figure which shows the example of a screen of the car navigation which displays specific information. The figure which shows the example of a screen of a license issuing apparatus. The flowchart which shows the process of a license issuing apparatus. The figure which shows the example of the screen of a car navigation system which inputs a license, and an external appearance. The flowchart which shows the process of a content decoding apparatus. The flowchart which shows the detail of a process of a key ring analysis part. The figure which shows the whole structure of the HDD replacement | exchange system in another Example (Example 2). The flowchart which shows the process which extracts the data key in another Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100: Content decoding apparatus 200: Content creation apparatus 300: License issuing apparatus 500: DVD 101: Content input part 120: Unique information output part 130: Key position input part 140: Terminal key recording part 150: Key ring analysis part 160: Map Data decoding unit 170: Map data recording unit
210: Data key recording unit 220: Map data encryption unit 22 230: Terminal key table recording unit 240: Key ring generation unit 250: Content output unit 260: Management table creation unit 280: Terminal information recording unit 290: Map data recording unit 310 : Terminal ID table recording unit 320: Unique information input unit 330: Key position search unit 340: Key position output unit 340

Claims (14)

In a content management system in which a content creation device that creates encrypted content, a content decryption device that decrypts content, and a license issuance device that issues a license to use the content are connected to each other by communication means ,
The content creation device includes: a terminal key table recording unit that records a correspondence between a terminal key and a key position for each device; a data key recording unit that records a data key for encrypting content; and the data using the terminal key A key bundle generation unit that creates a key bundle by storing encryption information obtained by encrypting a key at a position indicated by the key position; a content encryption unit that encrypts the content using the data key; and An encrypted content and a content output unit for outputting the key ring;
The license issuing device; a terminal ID table recording unit that records the correspondence between the unique information for each device and the key position;
A unique information input unit for inputting the unique information, a key position search unit for searching for a key position in a key ring for the unique information, and a key position output unit for outputting the key position,
The content decrypting device; a content input unit for inputting an encrypted content created by the content creating device and a key ring used for encrypting the data key; A key position input unit for inputting a key position unique to the device in the key ring, and extracting cryptographic information determined by the key position from the information of the key ring, and performing a calculation process specific to the device on the cryptographic information A content management system comprising: a key ring analysis unit that acquires a data key by using a content decrypting unit that decrypts content using the acquired data key. The content creation device uses a terminal information recording unit that records a correspondence between unique information and a terminal key for each device, and uses the information recorded in the terminal information recording unit, and uses the terminal key table, the unique information, and the key. The content management system according to claim 2, further comprising: a management table creation unit that creates a terminal ID table that records the correspondence between positions. The content decryption device outputs a device key recording unit that holds a terminal key used for realizing the device-specific calculation processing in the key ring analysis unit, and device-specific information to the license issuing device The content management system according to claim 1, further comprising: a unique information output unit. 4. The content management system according to claim 1, wherein the key position input unit inputs key position information having a number of digits smaller than the number of digits of the data key. A content decrypting device for decrypting encrypted content,
A content input unit for inputting the content encrypted with the data key and the key ring used to encrypt the data key, and the key for inputting the key position specific to the device in the key ring obtained from the outside A position input unit, a key ring analysis unit that extracts cryptographic information determined by the key position from the key ring information, and obtains a data key by performing a device-specific calculation process on the cryptographic information; and And a content decrypting unit that decrypts the content using the data key. 6. The content decrypting apparatus according to claim 5, further comprising: a terminal key recording unit that holds a terminal key used for realizing arithmetic processing unique to the device in the key ring analyzing unit. 6. The content decrypting apparatus according to claim 5, further comprising a data key recording unit that records the data key. And a unique information output unit for outputting device-specific information to the license issuing device,
8. The content decrypting apparatus according to claim 5, wherein the key position input unit inputs a key position issued from a license issuing apparatus. 9. The content decrypting apparatus according to claim 5, wherein the key position input unit inputs key position information having a number of digits smaller than the number of digits of the data key. 10. The content decrypting apparatus according to claim 5, wherein the key position input unit is an input / output device having a touch screen. A content decryption processing method for decrypting encrypted content,
A step of inputting a content encrypted by a data key and a key ring used to encrypt the data key, and a key position input for inputting a key position unique to the device in the key ring obtained from the outside A key bundle analyzing step for extracting cryptographic information determined by the key position from the key bundle information and obtaining a data key by performing a device-specific calculation process on the cryptographic information; and And a step of decrypting the content using the data key. 12. The content decryption processing method according to claim 11, wherein a terminal key used for realizing the arithmetic processing unique to the device in the key ring analysis processing is held in the recording unit in advance. 12. The content decrypting method according to claim 11, wherein the data key is held in a recording unit in advance. 14. The content decryption processing method according to claim 11, wherein information on a key position having a number of digits smaller than the number of digits of the data key is input.

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