JP2004326277A - Method for distributing data - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively control improper access to limited data through the operation of a timepiece within a reproduction device or a terminal device. <P>SOLUTION: A method for storing reproduction license or the like in a storage media 15 attached to a data terminal device 45 connectable to a distribution server 1 is disclosed. Certification information which the storage medium has is authenticated so that the subject to which the reproduction license is distributed or sold via the storage media is restricted to the specific storage media having the function of determining term of use, so as to assist in controlling unauthorized access to limited content data. The function of determining the term of use is to update and record date data such as access time information in the storage media, with the access time information being updated not only when access ends but also at a plurality of time points. Even if a power supply is cut off immediately before the reproduction of service information ends, the storage media itself guarantees that the access time information is updated at least once. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to playback time limit management for content data such as moving images and music stored in a storage medium, and relates to a method of distributing data such as a playback license to a storage medium to which playback time limit management control is applied.
[0002]
[Prior art]
When renting image data and music data stored in a storage medium such as a memory card, a user can reproduce images and music using a reproducing device within a preset reproduction time limit. Playback is managed based on the time detected by the user's playback device and the playback time limit information written when the digital data is stored in the storage medium. If the current time detected by the user's playback device is falsified, the content can be played back even though the playback time limit has passed.
[0003]
As a countermeasure against time tampering of the playback apparatus, for example, there is a technique described in Patent Document 1. That is, the data writing device sets a time limit for outputting data by the data reading device, and writes the data, the time limit, and the date and time of writing the data and the time limit on the storage medium to the storage medium. The data reading device determines whether the data written in the storage medium can be output based on the time limit read from the storage medium, the writing date and time, and the detected current date and time, and can output the data. And reads and outputs data from the storage medium. It is assumed that when the time limit for outputting data has elapsed, the current date and time detected by the detection unit of the data reading device is changed to the date and time before the writing date and time, and illegal data output is attempted. In this case, since the improperly changed current date and time is before the date and time when the data was written, the determination unit does not determine that the data can be output. Further, the writing date and time is updated to the current time at the end of the reproducing process.
[0004]
[Patent Document 1]
JP-A-2002-259917 (paragraph 99, FIG. 7)
[0005]
[Problems to be solved by the invention]
According to the technique disclosed in Patent Document 1, by recording date and time data on a storage medium such as a memory card, even if a clock inside the terminal is operated, illegal reproduction of time-limited content can be suppressed, but this is not sufficient. Has been found by the present inventors. First, it is assumed that it is not sufficient to simply update the current time of the storage medium at the end of reproduction. For example, if the power is turned off immediately before the end of the content reproduction, the current time of the storage medium may not be updated at all. Secondly, since the reproduction device has the function of suppressing the illegal reproduction of the time-limited content, unauthorized access is still possible if the reproduction device is changed.
[0006]
An object of the present invention is to provide a technique for effectively suppressing unauthorized access to time-limited data by operating a clock inside a playback device or a terminal device.
[0007]
The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.
[0008]
[Means for Solving the Problems]
The outline of a representative invention among the inventions disclosed in the present application will be briefly described as follows.
[0009]
[1] According to a first aspect of the present invention, data is distributed upon receiving authentication via a network. This data distribution method is a method of using a data terminal device connectable to a distribution server to store predetermined information in a storage medium mounted on the data terminal device. A first process of sending the held certification information to the distribution server, and receiving information returned in response to the first process, and using the received information as the predetermined information in the storage medium based on the first process. A second process for storing a decryption key for decryption and restriction information for restricting access to the usage information. The restriction information includes access time limit information and access time information, an initial value of the access time information is time information included in the received information, and the proof information indicates a specific storage medium. Information. The specific storage medium performs an access determination operation of determining whether or not access to the usage information is possible based on time information supplied from outside and the restriction information, and updating the access time information based on the time information. When the time information is later than the access time limit indicated by the access time limit information in the determination of the access permission or the time information is earlier than the access time indicated by the access time information, it is determined that the access is not possible. In other cases, access is determined to be permitted, and the access determination operation is performed at least at the start of access to the usage information and at the end of access.
[0010]
In the above means, when the usage information (content data) is reproduced, the date and time data such as the access time information is updated and recorded in the storage medium. The indicated time difference is narrowed, and the time finally indicated by the access time information exceeds the time indicated by the term information. Once exceeded, it is disabled. Even if the user returns the clock in the terminal to the date and time before the usage restriction, the reproduction is no longer possible. This makes it possible to suppress illegal reproduction of time-limited use information even when a clock inside a terminal such as a reproduction device is operated. Since the access time information is updated not only at the end of the access but also at the start of the access, at least one update of the access time information is guaranteed even if the power is shut off immediately before the end of the reproduction of the usage information. Since the storage medium has the function of suppressing the unauthorized reproduction of the time-limited use information, it is easy to still operate the unauthorized access suppression function even if the playback device is changed. Therefore, if the above data distribution method is used, the distribution or sale of the reproduction license via the storage medium is limited to the storage medium having the use expiration date judging function by authentication of the certification information. It can help prevent unauthorized access.
[0011]
[2] According to a second aspect of the present invention, data is distributed after being authenticated by the data terminal device. This data distribution method is a method of storing predetermined information in a storage medium attached to the data terminal device using a data terminal device, and acquiring certification information from the storage medium in response to a request for issuing a decryption key. A first process for determining whether or not authentication of the proof information is permitted; and, after authenticating the proof information, as the predetermined information, a decryption key for decrypting usage information and an access restriction on the usage information. And a second process for storing the restriction information to be performed. The restriction information includes access time limit information and access time information, and an initial value of the access time information is predetermined time information. The certification information is information indicating that the storage medium is a specific storage medium. The specific storage medium has an unauthorized access suppression function similar to the above. In the same manner as described above, according to this data distribution method, the authentication or certification of the certification information limits the distribution or sale of the reproduction license via the storage medium to the storage medium having the use expiration date determination function. It can support access deterrence.
[0012]
[3] In the specific storage medium with the unauthorized access suppression function, the access determination operation may be performed at least when the operation power is turned on to the storage medium and when the operation power is cut off.
[0013]
[4] The predetermined information may include content data to be decrypted. If not included, the content data may be distributed by another storage medium such as a CD-ROM.
[0014]
The specific storage medium is, for example, a memory card having an electrically rewritable flash memory and a control circuit.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 illustrates a content data distribution system. A data terminal device (data processing device) 3 with a usage term, typically shown, is connected to a network 2 to which the content server 1 is connected. The data terminal device with usage period (also simply referred to as a data terminal device) 3 includes a download reproduction unit (download unit and reproduction unit) 10, a usage period determination unit (use restriction unit) 11, and a terminal internal clock 12. A non-volatile storage device (also simply referred to as a memory card) 13 is detachably attached to the data terminal device 3 as a storage medium. The memory card 13 includes an electrically erasable and writable non-volatile memory (non-volatile storage circuit) 14 such as a flash memory.
[0016]
An outline of a function of downloading content data by the data terminal device 3 will be described. When the memory card 13 is attached to the data terminal device 3 and the download of the content data is instructed to the data terminal device 3, the data terminal device 3 sends the content data with usage period (use information) from the content server 1 and the corresponding content data. Download the playback license (usage information license) and write it to the memory card. Further, download date and time data is obtained from the server 1 and written to the memory card 13. The date and time data written in the memory card 13 is card date and time data. Although not particularly limited, the downloaded date and time data is incorporated into a license format by the use restriction determination unit and stored in the secure area of the nonvolatile memory 14 as a secure license. Although there is no particular limitation, the secure license also holds the usage period. Although not particularly limited, the reproduction license is also stored in the secure area of the nonvolatile memory 14.
[0017]
An outline of a function of reproducing the content data with a time limit by the data terminal device 3 will be described. When the reproduction is instructed to the data terminal device 3, the data terminal device 3 reads the reproduction license from the memory card 13. The usage period is extracted from the read reproduction license, and the usage period of the content data is sent to the usage period determining unit 11. The usage expiration unit 11 determines whether access is possible based on the usage expiration date (access expiration information) of the content data, the terminal date / time data (time information) indicated by the terminal internal clock 12, and the card date / time data (access time information) held by the card. I do. That is, access is performed when the date and time indicated by the terminal date and time data is later than the access date and time indicated by the access date and time information, or when the date and time indicated by the terminal date and time data is earlier than the date and time indicated by the card date and time data. It is determined to be no, and in other cases it is determined that access is possible. If the access is permitted, the content data in the memory card 13 is read and reproduced. If the access is not permitted, the reproduction license and the like are deleted. The expiration date determination unit 11 updates the card date and time data in the memory card 13 based on the terminal date and time data together with the access permission / inhibition determination.
[0018]
The update of the card date and time data is performed not only at the time of starting access represented by the above-described access permission determination but also at the end of access. Further, for example, the operation may be performed when at least the operation power is turned on to the memory card and when the operation power is cut off.
[0019]
FIG. 2 shows an example in which another data terminal device 4 is connected to the content data distribution system. The data terminal device 4 includes a download playback unit (download unit and playback unit) 10 and a terminal internal clock 12. A non-volatile storage device (also simply referred to as a memory card) 15 as a storage medium is detachably attached to the data terminal device 3. The memory card 15 includes a use period determination unit (use restriction unit) 16 and a nonvolatile memory 14.
[0020]
An outline of the content data download function of the data terminal device 4 will be described. When the memory card 15 is inserted into the data terminal device 4 and the download of the content data is instructed to the data terminal device 4, the data terminal device 4 sends the content data with usage period (use information) from the content server 1 and the corresponding content data. The reproduced license (usage information license) is downloaded and written to the memory card 15. Further, the download date and time data is obtained from the server 1 and written to the memory card 15. The date and time data written in the memory card 15 is card date and time data. Although not particularly limited, the downloaded date and time data is incorporated into a license format by the use restriction determination unit and stored in the secure area of the nonvolatile memory 14 as a secure license. Although not particularly limited, the reproduction license is also stored in the secure area of the nonvolatile memory 14.
[0021]
The outline of the playback function of the content data with a time limit will be described. When the data terminal device 4 is instructed to reproduce the data, the data terminal device 4 causes the usage period determination unit 16 to acquire a reproduction license for the memory card 15. The usage period determination unit 16 extracts a usage period from the read reproduction license. The expiration date determining unit 16 determines the expiration date (access expiration information) of the content data, the terminal date / time data (time information) indicated by the terminal internal clock 12, and the card date / time data (access time information) held in the nonvolatile memory 14. Determine whether access is possible. That is, access is performed when the date and time indicated by the terminal date and time data is later than the access date and time indicated by the access date and time information, or when the date and time indicated by the terminal date and time data is earlier than the date and time indicated by the card date and time data. It is determined to be no, and in other cases it is determined that access is possible. If the access is permitted, the usage period determination unit 16 makes the download reproduction unit 10 read the content data in the memory card 13 and make the content data reproducible. The usage period determination unit 16 updates the card date and time data in the memory card based on the terminal date and time data together with the access permission / non-permission judgment.
[0022]
The update of the card date and time data is performed not only at the time of starting access represented by the above-described access permission determination but also at the end of access. Further, for example, the operation may be performed when at least the operation power is turned on to the memory card and when the operation power is cut off.
[0023]
FIG. 3 exemplifies an outline of usage restrictions based on the card date and time data updated based on the terminal date and time data. The date and time (borrowed date) Ts and the expiration date (return date) Te of downloading the content data are fixed. The current time is the time Tc indicated by the terminal date and time data. The access date and time is the time Tacs indicated by the card date and time data. If the card date / time data is not updated, the date / time indicated by the data is fixed to the date / time (borrowed date) Ts at which the content data was downloaded. If the card date / time data Tacs is not updated as in (a), the card can be used wherever the current date / time Tc is between the borrowed date Ts and the expiration date Te, for example, as shown in (b). If Tc has exceeded the expiration date Te, it becomes unusable. However, if the terminal clock is operated to move between the date on which the current date and time was borrowed and the expiration date, the content data can be used illegally. On the other hand, in FIGS. 1 and 2, the card date and time data in the memory card is updated based on the terminal date and time data, so that the access date and time and the date and time indicated by the certain card date and time data Tacs as shown in FIG. The time is reduced for each update, and finally exceeds the usage period Te. If it exceeds one end, it will be unavailable. Even if the user returns the clock in the terminal to the date and time before the usage restriction, the reproduction is no longer possible. As a result, even if the clock inside the data terminal device is operated, it is possible to sufficiently suppress illegal reproduction of the time-limited content.
[0024]
Since the update of the card date and time data is performed not only at the end of the access but also at the start of the access, at least one update of the access time information is guaranteed even if the power is cut off immediately before the end of the reproduction of the usage information. As shown in FIG. 2, since the non-volatile storage device has the function of suppressing the unauthorized reproduction of the time-limited use information, it is easy to still operate the unauthorized access restriction function even if the reproducing device is changed.
[0025]
FIG. 4 shows a specific example of the use period judging unit 11 and the terminal internal clock 12. A circuit block indicated by reference numeral 20 is a microcomputer that realizes at least the use period determination unit 11 and the terminal internal clock 12. FIG. 4 shows the inside of the microcomputer 20 by functional blocks. The microcomputer 20 includes a date / time data acquisition / creation unit 21, an encryption unit 22, a license creation unit 23, a secure area access unit 24, a date / time data extraction unit 25, a decryption unit 26, a usage restriction determination unit 26, and a terminal clock circuit 27. Having.
[0026]
The non-volatile memory 14 has a secure area (access restricted area) 14A and a non-secure area (access unrestricted area) 14B. Write access to the secure area 14A is enabled by authentication of the certification information in the memory card 13 outside the memory card, for example, by the terminal device 20 or the server 1. Reading from the outside to the secure area 14A is permitted on condition that authentication is obtained for the proof information provided from outside. Although not shown, the memory card 13 has a card controller that controls access to the nonvolatile memory 14 and controls the interface with the outside. The secure area access unit 24 is interfaced via the card controller.
[0027]
In this example, after the data is encrypted by the card date / time data encryption unit 22, the data is embedded in the secure license by the license creation unit 23, and is recorded in the secure area 14A of the nonvolatile memory 14 under the control of the secure area access unit 24. It has become.
[0028]
The date and time data acquisition and creation unit 21 is a circuit that acquires date and time data (download date and time data) from the server 1 when the server 1 downloads content data or a license. As shown in FIG. 5, the format of the acquired date and time data is configured by 16-byte data.
[0029]
The encryption unit 22 encrypts the date and time data obtained from the server. Although the encryption method is not particularly limited, the same AES (Advanced Encryption Standard) method used in the encryption / decryption processing of the content is used. The key for encrypting the date and time data uses attribute information unique to the memory card, for example, the serial number of the card.
[0030]
The license creation unit 23 creates the secure license by embedding the acquired and encrypted date and time data in, for example, the content key portion in the license format.
[0031]
The secure area access unit 24 writes the secure license including the date and time data in the secure area 14A of the nonvolatile memory. Writing to the secure area 14A requires the write authentication. The date and time data extracting unit 25 reads out the license including the encrypted date and time data from the secure area, and extracts the encrypted date and time data. The reading authentication is required for reading the secure area 14A.
[0032]
The decryption unit 26 decrypts the encrypted date and time data extracted from the secure license by AES. The same key as the key used in the encryption unit 22 is used for decryption.
[0033]
As described above, the use restriction determining unit 27 determines whether the usage period has expired and also determines whether the clock in the terminal has been operated by the user. The details of the determination have already been described with reference to FIG. If it is determined that the operation has been performed, all licenses in the card are deleted. The terminal clock circuit 28 obtains the date from the clock in the terminal.
[0034]
Although not shown, each functional block in FIG. 4 is used for a central processing unit, a floating point arithmetic unit, a ROM (Read Only Memory) having a processing program for them, a work area of the central processing unit, and the like. It comprises a RAM (random access memory), a real-time clock circuit, a timer, an input / output circuit, and the like.
[0035]
The operation of the circuit of FIG. 4 will be described. First, the operation when communicating with the server 1 or when downloading a content or a license will be described.
[0036]
When connected to the server 1, date / time data is acquired from the server 1 by the date / time data acquisition / creation unit 21. In order that the acquired date and time data can be incorporated into the content key area in the license format, the date and time data has, for example, a 16-byte data configuration illustrated in FIG. When the date and time is 15: 30: 45: 00 on Thursday, October 10, 2002, when this date and time data is expressed in hexadecimal, it is "07D2000A000A0004000F001E002D0000h".
[0037]
The encryption unit 22 encrypts the 16-byte date / time data created by the date / time data acquisition / creation unit 21 by the AES method. The encryption key uses a serial number unique to the card.
[0038]
The license creation unit 23 embeds the encrypted date and time data in the content key portion of the license to create one license. The created license is written to the secure area of the memory card by the secure area access unit 24. If 128 licenses can be recorded in the secure area, a license including date and time data is written at the last 128th. Writing to the secure area 14A is enabled upon receiving the write authentication.
[0039]
Next, the operation of the usage restriction determination process will be described. The secure area access unit 24 reads a secure license including the encrypted date and time data from the secure area 14A. Read access to the secure area is enabled by receiving the read authentication. The date and time data extracting unit 25 extracts 16 bytes of encrypted date and time data from the read license. The decoding unit 26 decodes the 16-byte date / time data by the AES method. The key to be decrypted uses the same serial number unique to the card as when it was encrypted. Next, the internal clock of the terminal is acquired by the internal clock acquiring unit 28. The use restriction determining unit 27 determines whether the time limit has expired or an unauthorized operation has been performed using the use time limit, the terminal date / time data, and the card date / time data.
[0040]
Next, the operation of updating the date and time data will be described. Since there is no power supply in the card, the card itself cannot update the date and time data. Therefore, as described above, the date and time data is updated at the time of connection with the server and at the time of reproducing and displaying the content (at the time of use restriction determination processing). However, the update may not be performed for a long time when the connection with the server is not made or when the content is not reproduced and displayed. The timing of updating the date and time data may be determined when the memory card is inserted and removed from the data terminal, or when the memory card is attached to the data terminal, in addition to the above-described access start and end times. It may be a time when a power-on of the data terminal is instructed, a time when a power-off is instructed, or the like. When the power of the data terminal is turned off, the data terminal may be updated by adding the time measured by the timer inside the microcomputer to the date and time data recorded on the card.
[0041]
FIG. 6 shows a specific example of the expiration date judging unit 16 built in the memory card 15. The expiration date judging section 16 is constituted by a microcomputer 30. In FIG. 6, the microcomputer 30 constitutes a card controller together with the external interface controller 31 and the memory controller 32. FIG. 6 illustrates the microcomputer 30 by a functional block constituting a part of the function of the use period judging unit 16. The illustrated functional blocks realized by the microcomputer 30 are an encryption unit 33, a license creation unit 34, a date and time data extraction unit 35, a decryption unit 36, a use expiration date extraction unit 37, and a use restriction determination unit 38.
[0042]
The external interface controller 31 performs external interface control in accordance with a predetermined memory card interface specification in accordance with an instruction from the microcomputer 30. The memory controller 32 controls erasing, writing, and reading access to the nonvolatile memory 14 according to an instruction from the microcomputer 30.
[0043]
Although not particularly shown, the microcomputer 30 includes a central processing unit, a floating-point arithmetic unit, a ROM (Read Only Memory) having a processing program for them, and a RAM (random and random) used for a work area of the central processing unit. Access memory), a real-time clock circuit, a timer, and an input / output circuit. The microcomputer 30 has a function of realizing the use period determination unit 16 and performing an arithmetic operation for authentication, an address arithmetic operation for accessing the nonvolatile memory 14, and the like in accordance with the operation program.
[0044]
The non-volatile memory 14 has a secure area (access restricted area) 14A and a non-secure area (access unrestricted area) 14B. Write access to the secure area 14A is enabled by authentication of the certification information in the memory card 15 outside the memory card, for example, by the terminal device 20 or the server 1. Reading from the outside to the secure area 14A is permitted on condition that authentication is obtained for the proof information provided from outside. The certification information in the memory card 15 is a memory card provided with the use term determination function described in FIGS. 2 and 6 and the like, and includes information that can be distinguished from other memory cards.
[0045]
In this example, after being encrypted by the card date / time data encryption unit 33, the data is embedded in a secure license by the license creation unit 34, and is recorded in the secure area 14A of the nonvolatile memory 14 via the memory controller 32. I have. Although there is no particular limitation, the secure license also holds the expiration date of the content.
[0046]
When the download reproduction unit 10 in FIG. 2 downloads the content data and the license from the server, date and time data (download date and time data) is acquired from the server 1. The date and time data accompanies the content license. As shown in FIG. 5, the format of the acquired date and time data is configured by 16-byte data.
[0047]
The encryption unit 33 receives and encrypts the date and time data acquired from the server. Although the encryption method is not particularly limited, the same AES (Advanced Encryption Standard) method used in the encryption / decryption processing of the content is used. The key for encrypting the date and time data uses attribute information unique to the memory card, for example, the serial number of the card.
[0048]
The license creating unit 34 creates a secure license by embedding the acquired and encrypted date and time data in, for example, a content key portion in a license format.
[0049]
The created secure license is written into the secure area 14A of the nonvolatile memory via the memory controller 32. Writing to the secure area 14A requires the write authentication. When the secure license including the encrypted date and time data is read from the secure area 14A, the date and time data extracting unit 36 extracts the encrypted date and time data therefrom. When the secure license is read from the secure area 14A, the usage period extracting unit 37 extracts the usage period data therefrom. The reading authentication is required for reading the secure area 14A.
[0050]
The decryption unit 36 decrypts the encrypted date and time data extracted from the secure license by AES. The same key as the key used in the encryption unit 33 is used for decryption.
[0051]
As described above, the use restriction determination unit 27 determines whether the usage period has expired and determines whether the clock 12 in the data terminal 4 has been operated by the user. The details of the determination have already been described with reference to FIG. If it is determined that the operation has been performed, all the licenses in the secure area 14A are deleted.
[0052]
The operation of the circuit of FIG. 6 will be described. First, the operation when communicating with the server 1 or when downloading a content or a license will be described.
[0053]
When the data terminal device 4 is connected to the server 1, it inputs the date and time data from the server 1 via the external interface controller 31. At the same time, the reproduction expiration date data is also input. The reproduction expiration date uses, for example, the one included in the reproduction license. The input date and time data has a 16-byte data configuration illustrated in FIG. The date and time data is encrypted by the encryption unit 33 by, for example, the AES method. The encryption key uses a serial number unique to the card.
[0054]
The license creation unit 34 embeds the encrypted date and time data in the content key portion of the license to create a secure license. The created license is written to the secure area 14A of the memory card 14 via the memory controller 32. If the secure area can record 128 licenses, the secure license is written at the last 128th. Writing to the secure area 14A is enabled upon receiving the write authentication.
[0055]
Next, the operation of the usage restriction determination process will be described. The secure license is read from the secure area 14A via the memory controller 32. Read access to the secure area is enabled by receiving the read authentication. The date and time data extracting unit 35 extracts 16 bytes of encrypted date and time data from the read license. The expiration date extracting unit 37 extracts the expiration date. The decoding unit 36 decodes the 16-byte date and time data by the AES method. The key to be decrypted uses the same serial number unique to the card as when it was encrypted. Next, the date and time in the terminal are acquired. The use restriction determining unit 38 determines whether the time limit has expired or whether an illegal operation has been performed using the use time limit, terminal date / time data, and card date / time data.
[0056]
Next, the operation of updating the date and time data will be described. Since there is no power supply in the card, the card itself cannot update the date and time data. Therefore, as described above, the date and time data is updated at the time of connection with the server and at the time of reproducing and displaying the content (at the time of use restriction determination processing). However, the update may not be performed for a long time when the connection with the server is not made or when the content is not reproduced and displayed. The timing of updating the date and time data may be determined when the memory card is inserted and removed from the data terminal, or when the memory card is attached to the data terminal, in addition to the above-described access start and end times. It may be a time when a power-on of the data terminal is instructed, a time when a power-off is instructed, or the like. When the power of the data terminal is turned off, the data terminal may be updated by adding the time measured by the timer inside the microcomputer to the date and time data recorded on the card.
[0057]
The update process may be performed at another timing. That is, in the case where the memory card performs data access by dividing the data in the sector unit by the file memory method, after it is determined that the access is permitted in the access determination operation at the start of the access, the memory card is accessed every subsequent sector or every predetermined plurality of accesses. May perform the access determination operation. In the access determination operation for access to data divided in units of a sector in this manner, in the second and subsequent access determination operations, it is determined that access is possible even if the time information is after the access time limit indicated by the access time limit information. You may do it. When the access determination operation is performed many times, the inconvenience that reproduction is interrupted due to the expiration of a time limit during the reproduction of the usage information can be easily eliminated.
[0058]
FIG. 7 illustrates a format of a reproduction license, and FIG. 8 illustrates a format of a secure license. The content ID is an identifier uniquely assigned to each content. The transaction ID is a unique identifier for each transaction. The transaction ID includes the number of reproducible times (the number of times the license can be read), the number of times the license can be moved (the number of times the license can be moved), and an identifier of a safe level (protection strength). The media access condition is an access condition that can be forced inside the media. The content key is a key used when encrypting the content, and is also a decryption key used when decrypting the content. The decoder access condition indicates an access condition that can be forced inside the decoder for reproduction. The decoder access condition includes a reproduction size (a content size that can be reproduced with one license) and a use period (a usable period). The extended media access condition is a flag indicating whether to perform certificate authentication and PIN authentication. The playback license has a content key, while the secure license is configured by replacing the content key of the playback license with card date and time data.
[0059]
Certificate authentication, for example, certificate information for receiving write authentication in a secure area, or a PIN for performing personal authentication using a PIN (Personal Identification Number) is stored in the nonvolatile memory 14.
[0060]
FIG. 9 illustrates an authentication (write authentication) processing procedure at the time of writing a license. First, it is determined whether or not to perform certification authentication (S1). If so, a certificate (media class certificate) having authentication information and a public encryption key is read from the memory card (S2) and transmitted to the server. (S3). The server verifies the certificate (S4), and if authenticated, the writing of the reproduction license and the secure license in the secure area of the memory card is permitted (S5). The media class certificate includes, for example, certificate information that can distinguish the memory card 15 having the function of determining the expiration date from another memory card not having the function.
[0061]
FIG. 10 illustrates an authentication (reading authentication) processing procedure at the time of reading a license. First, it is determined whether or not to perform certification authentication (S11). If so, the data terminal transmits a certificate (decoder class certificate) having authentication information and a public encryption key to the memory card (S12). The memory card verifies the certificate (S3). If the certificate is authenticated, reading of the reproduction license and the secure license from the secure area of the memory card is permitted (S14). If the certification authentication is not performed in the determination in the process S11, it is determined whether the PIN authentication is performed (S15). If the authentication is performed, the PIN is transmitted from the data terminal device to the memory card (S16). Verify the PIN. If the PIN is valid, the license is read (S14). When the PIN is invalid, when the PIN authentication is not performed, and when the certification authentication cannot be obtained, the processing is terminated as it is.
[0062]
FIG. 11 shows an example of a reproduction processing flow of the content with a usage term. In the case of using the reproduction license to reproduce the content with the expiration date, first, the expiration date determination process R21 is performed. If the reproduction is possible, the card date and time data updating process R22 is performed, and the reproduction end of the content with the expiration date is determined ( S23) If not finished, the card date / time data update processing R22 is repeated at predetermined intervals. When it is determined that the reproduction has been completed, the card date and time update processing R22 is finally performed, and the processing ends.
[0063]
FIG. 12 shows a detailed example of the usage term determination process R21. The date and time information of the data terminal device is obtained, and terminal date and time data is created (S31). Next, necessary certification authentication or PIN authentication is performed to obtain card date and time data from the memory card (S32), and obtain a usage period from the license (S33). The usage restriction and the card date and time data are compared (S34), and if the usage period is equal to or less than the card date and time data, it is determined that the period has expired and the process is terminated. If the term of use> card date data, the terminal date data and the card date data are compared (S35). If the terminal date / time data ≦ card date / time data, the terminal date / time data is determined to be invalid, and all licenses held by the memory card are deleted (S36). If the terminal date / time data> card date / time data, the date / time data of the card is updated to the terminal date / time data (S37).
[0064]
FIG. 13 shows a detailed example of the card date / time data update processing R22. The date and time information of the data terminal device is acquired, and terminal date and time data is created (S41). Next, necessary certification authentication or PIN authentication is performed to obtain card date and time data from the memory card (S42). The terminal date / time data and the card date / time data are compared (S43). If terminal date / time data ≦ card date / time data, the terminal date / time data is determined to be invalid, and all licenses held by the memory card are deleted (S44). If the terminal date / time data> card date / time data, the date / time data of the card is updated to the terminal date / time data (S45). The processing in FIG. 13 does not acquire the expiration date from the license and does not end the processing in the case of FIG. Therefore, it is possible to eliminate the inconvenience that the reproduction expiration arrives during the reproduction of the content with usage expiration and the reproduction is interrupted.
[0065]
FIG. 14 shows a playback terminal device 40 for data with a time limit. The playback terminal device 40 shown in FIG. 3 has a playback unit 41, and is configured as a playback-only device in which the function of downloading content data and a license is omitted from the terminal device 4 in FIG. The content reproduction processing shown in FIGS. 11 to 13 can be performed.
[0066]
FIG. 15 shows a download terminal device 45. The download terminal device 45 shown in the figure is a terminal device exclusively for downloading content data and a license, in which the content data reproduction function is omitted from the download reproduction unit 10 in the terminal device 4 described in FIG. The download-only terminal device 45 includes a host interface unit 46, a memory card interface unit 47, and a data processing unit 48. The memory card 15 attached to the memory card interface unit 47 has a content license for decoding contents, Initially, reproduction time limit data for restricting access to content and card date and time data are stored. The data processing section 48 outputs the certification information held by the memory card 15 to the outside from the host interface section 46 together with the request for receiving the content license, and in response to this, for example, information returned from the server 1 to the host interface section 46 Is received from the memory card interface unit 47 and stored in the memory card 15. The received information includes a content key used for decrypting the content, reproduction time limit data for restricting access to the content, and card date and time data. The certification information is information indicating that the memory card 15 has a use expiration date determination function. By distributing or selling the content and its reproduction license to the memory card using this download terminal device, the target storage medium is limited to the memory card 15 having the use expiration date determination function. It can help prevent unauthorized access.
[0067]
The configuration in FIG. 15 is not limited to a configuration as a terminal device connected to a network. Although not particularly shown, the download terminal device 45 itself may be a content server, and from a different viewpoint, it becomes a stand-alone distribution terminal device.
[0068]
Although the invention made by the inventor has been specifically described based on the embodiment, the present invention is not limited to the embodiment, and it goes without saying that the invention can be variously modified without departing from the gist thereof.
[0069]
For example, although the data terminal having the download function described so far has been described as having the function of downloading and distributing both the content and the content license, the present invention is not limited to this, and it is possible to download or distribute only the content license. There may be. In a data terminal device having a reproduction function, there is a case where the content does not have to be stored in the same memory card as the license. In that case, the content data may be accessed using a removable disk drive such as a CD-ROM or a DVD-RAM. Alternatively, access may be made from a hard disk drive.
[0070]
Further, in the above description, an example is shown in which date and time data is encrypted, embedded in a license, and recorded in the secure area. However, the encryption may be omitted. Since the date and time data is embedded in the license without being encrypted, the processing amount is small. Further, the date and time data may be encrypted and recorded in the non-secure area. It can also be used for storage media without a secure area. Further, the date and time data may be recorded in the non-secure area without being encrypted. It can be used for a storage medium without a secure area, and can be realized with a minimum configuration because there is no need to perform AES encryption / decryption processing. However, it should be noted that there is a high possibility that the user operates the date and time data.
[0071]
【The invention's effect】
The effects obtained by the representative inventions among the inventions disclosed in the present application will be briefly described as follows.
[0072]
In other words, if the data distribution method according to the present invention is used, the distribution or sale of the reproduction license via the storage medium is limited to a specific storage medium having the expiration date determination function by authentication of the certification information. It is possible to support the suppression of unauthorized access to attached content data. The use expiration date determination function is to update and record date and time data such as access time information in a storage medium such as a memory card, and to update the access time information not only at the end of access but also at a plurality of times. Even if the power is shut off immediately before the end of the reproduction of the information, at least one update of the access time information is guaranteed. Since the nonvolatile storage device has the function of suppressing unauthorized use of time-limited use information, it is easy to still operate the unauthorized access suppression function even if the playback device is changed.
[Brief description of the drawings]
FIG. 1 is a block diagram of a content data distribution system to which the present invention is applied.
FIG. 2 is an explanatory diagram showing an example in which another data terminal device is connected to a content data distribution system to which the present invention has been applied.
FIG. 3 is an explanatory diagram exemplifying an outline of usage restrictions based on card date and time data updated based on terminal date and time data.
FIG. 4 is a block diagram showing a specific example of a use period determination unit and a terminal internal clock in FIG. 1;
FIG. 5 is an explanatory diagram illustrating a format of date and time data.
FIG. 6 is a block diagram showing a specific example of a use period determining unit incorporated in the memory card of FIG. 2;
FIG. 7 is an explanatory diagram illustrating a format of a reproduction license.
FIG. 8 is an explanatory diagram illustrating a format of a secure license.
FIG. 9 is a flowchart illustrating an authentication (write authentication) processing procedure at the time of writing a license.
FIG. 10 is a flowchart illustrating an authentication (read authentication) processing procedure at the time of reading a license.
FIG. 11 is a flowchart illustrating an example of a process of reproducing content with a usage term.
FIG. 12 is a flowchart illustrating details of a use expiration date determination process R21 in FIG. 11;
FIG. 13 is a flowchart illustrating details of a card date / time data update process R22 in FIG. 11;
FIG. 14 is a block diagram illustrating a playback terminal device for data with a time limit;
FIG. 15 is a block diagram illustrating a download terminal device.
[Explanation of symbols]
1 server
2 Network
3 Data terminal equipment
4 Data terminal equipment
10 Download generator
11 Expiration date judgment unit
12 Terminal internal clock
13 Memory card
14 Non-volatile memory
14A Secure area (access restricted area)
14B Non-secure area (access unrestricted area)
15 Memory card
16 Expiration date judgment section
20 Microcomputer
30 microcomputer
40 playback terminal device
41 Playback unit
45 Download-only terminal
46 Host interface section
47 Memory card interface
48 Data processing unit

Claims (6)

A data distribution method for storing predetermined information in a storage medium mounted on the data terminal device using a data terminal device connectable to a distribution server,
A first process of sending proof information held by the storage medium to the distribution server together with a request for receiving a decryption key;
Receiving information returned in response to the first processing, and based on the information, as the predetermined information, a decryption key for decrypting usage information and restriction information for restricting access to usage information. And a second process for storing
The restriction information includes access time limit information and access time information,
The initial value of the access time information is time information included in the received information,
The certification information is information indicating that the storage medium is a specific storage medium,
The specific storage medium performs an access determination operation of determining whether or not access to the usage information is possible based on time information supplied from outside and the restriction information, and updating the access time information based on the time information. When the time information is later than the access time limit indicated by the access time limit information in the determination of the access permission or the time information is earlier than the access time indicated by the access time information, it is determined that the access is not possible. And determining that the access is permitted in other cases, and performing the access determination operation at least at the start and end of the access to the usage information. A data distribution method for storing predetermined information in a storage medium mounted on the data terminal device using a data terminal device connectable to a distribution server,
A first process of sending proof information held by the storage medium to the distribution server together with a request for receiving a decryption key;
Receiving information returned in response to the first processing, and based on the information, as the predetermined information, a decryption key for decrypting usage information and restriction information for restricting access to usage information. And a second process for storing
The restriction information includes access time limit information and access time information,
The initial value of the access time information is time information included in the received information,
The certification information is information indicating that the storage medium is a specific storage medium,
The specific storage medium performs an access determination operation of determining whether or not access to the usage information is possible based on time information supplied from outside and the restriction information, and updating the access time information based on the time information. When the time information is later than the access time limit indicated by the access time limit information in the determination of the access permission or the time information is earlier than the access time indicated by the access time information, it is determined that the access is not possible. And determining that the access is permitted in other cases, and performing the access determination operation at least when the operation power is turned on to the storage medium and when the operation power is cut off. A data distribution method for storing predetermined information in a storage medium attached thereto using a data terminal device,
A first process of acquiring certification information from a storage medium in response to a decryption key issuance request, and determining whether or not the acquired certification information can be authenticated;
After authenticating the proof information, the storage medium includes, as the predetermined information, a decryption key for decrypting usage information and a second process of storing restriction information for restricting access to the usage information,
The restriction information includes access time limit information and access time information,
The initial value of the access time information is predetermined time information,
The certification information is information indicating that the storage medium is a specific storage medium,
The specific storage medium performs an access determination operation of determining whether or not access to the usage information is possible based on time information supplied from outside and the restriction information, and updating the access time information based on the time information. When the time information is later than the access time limit indicated by the access time limit information in the determination of the access permission or the time information is earlier than the access time indicated by the access time information, it is determined that the access is not possible. And determining that the access is permitted in other cases, and performing the access determination operation at least at the start and end of the access to the usage information. A data distribution method for storing predetermined information in a storage medium attached thereto using a data terminal device,
A first process of acquiring certification information from a storage medium in response to a decryption key issuance request, and determining whether or not the acquired certification information can be authenticated;
After authenticating the proof information, the storage medium includes, as the predetermined information, a decryption key for decrypting usage information and a second process of storing restriction information for restricting access to the usage information,
The restriction information includes access time limit information and access time information,
The initial value of the access time information is predetermined time information,
The certification information is information indicating that the storage medium is a specific storage medium,
The specific storage medium performs an access determination operation of determining whether or not access to the usage information is possible based on time information supplied from outside and the restriction information, and updating the access time information based on the time information. When the time information is later than the access time limit indicated by the access time limit information in the determination of the access permission or the time information is earlier than the access time indicated by the access time information, it is determined that the access is not possible. And determining that the access is permitted in other cases, and performing the access determination operation at least when the operation power is turned on to the storage medium and when the operation power is cut off. 5. The data distribution method according to claim 1, wherein the predetermined information includes content data to be decrypted. 5. The data distribution method according to claim 1, wherein the specific storage medium is a memory card having an electrically rewritable flash memory and a control circuit.

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