JP2003228525A - Memory card, content delivery system and content delivery method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small memory card that counts reproduced states of contents and ensures high security. <P>SOLUTION: The memory card has a card interface controller 6, a security processing part 5 controlled by the card interface controller to supply an encryption key to the card interface controller upon a content reproduction request, a memory core interface 7 including a binary counter controlled by the security processing part and the card interface controller to count a reproduction degree upon the content reproduction request, and a memory core 3 for recording the reproduction degree of each content when receiving the content reproduction request, and for outputting an encrypted content to the memory core interface unless the reproduction request exceeds an allowable reproduction degree. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a memory card content distribution system and a content distribution method for recording contents such as music data, and more particularly to a memory card having a security function, a content distribution system and a content distribution method. is there.

[0002]

2. Description of the Related Art As a purchase method called "reproduction restricted" in which a reproduction period and a reproduction number of times are set as a service with a low price setting, a digital content such as music and games is used by using a memory card. To have fun
CD (Compact Disc) is a purchase method that has started and can be played many times at any time.
Compared with package media such as c), the manufacturing cost has become cheaper and the content price has become lower accordingly.

However, in order to further reduce the price of each content, it is necessary to devise a method of limiting the time and the number of times that the content can be played and enjoyed as a part of the policy. When using the current memory card, there is a method to obtain usage count data at the same time when purchasing the content and count the usage count at the start or end of playback, but there is a long or short playback time or cancellation during playback. , It was difficult to promote because of unfairness in counting. That is, it is difficult to determine when to count the number of times of reproduction. For example, when counting at the start time, there is a problem that the music is counted at the beginning of a song. In addition, when counting at the end of a song, there is a problem in that it is possible to avoid counting up by stopping playback in the middle of the song and listening again. Even if you count in the middle of the song,
The playback can be stopped just before the count-up and the count-up can be skipped in the same manner. In order to prevent such a situation and to be fair, it is necessary to count the data reproduction amount, but it is technically difficult to realize with the current memory card. That is, the memory card itself cannot be provided with a function of counting the amount of reproduction by following the data reproduction speed.

That is, there is a risk that the count processing function of the external device is inevitably used and the device is modified to deceive the count. In addition, memory cards are built into many types of playback devices to play content, but in order to count the amount of playback, it is necessary to add a function to count the amount of playback to all of various external devices. However, it is complicated and there is a possibility that the small size and portable characteristics of the portable device may be impaired.
Also, when only some of the external devices have a counting function, the memory card is played back using only that part of the device, which limits the playback means of the memory card.

In an SD (Secure Digital) card or other memory card having a security function, encrypted content data and data of a decryption key for decrypting the data are stored, and both data are used. The content is being played while decrypting the data. The decryption key looks at the serial number peculiar to each memory card, and a decryption key matching the serial number is created and sent, so copy the content data and the decryption key to another memory card. However, the code cannot be decrypted. This content data can be copied to other memory cards, but when copied, the copy source decryption key will retain a record of the other copy and cannot be played back using your own memory card. It works. In other words, the content can be used only for the one purchased, although it may be moved in the memory medium. Also, when reproducing the content, the type of the reproduction device is checked to send the data only to the registered device having the security function, thereby preventing illegal copying of the content. A memory card with such a security function is a system that prevents illegal copying of contents.

Next, a conventional content writing process to an SD card will be described with reference to FIG. SD card 20
0 is connected to the content vending machine 201. The SD card 200 is a card interface controller 2
02, memory core 203, protected memory core 20
4. It has a key information recording unit 205. The content vending machine 201 has a content recording unit 206 and an encryption processing unit 207. Here, the user inputs a content write request 208 to the content vending machine 201. In response to the content write request 208, the content vending machine 201 outputs a key request to the card interface controller 202 of the SD memory card 200. Next, the card interface controller 202
Receives the key request and issues a request to the key information recording unit 205. Next, the key information recording unit 205 outputs the key information to the card interface controller 202. Next, the card interface controller 202 outputs the key information to the encryption processing unit 207.

Next, the encryption processing unit 207 outputs the decryption key and the encrypted content to the card interface controller 202. Next, the card interface controller 202 operates the protected memory core 20.
4, the decryption key is output, the encrypted content is output to the memory core 203, and the content is written to the SD memory card 200.

Here, the decryption key data is constructed as shown in FIG. A content name 209 that identifies the content is recorded. Furthermore, the decryption data 210 is recorded. Furthermore, copy status data 211 is recorded. The copy status data 211 is "1" when the content specified by the content name has already been copied to another SD card, for example.
Is recorded, and in this case, the SD card is set in a state in which reproduction is impossible. This is to prevent unlimited unauthorized copying. Further, "0" is recorded when it is not copied to another SD card, and it is set to a state where reproduction is possible if other conditions are satisfied.

Next, a conventional counting method for reproducing data will be described with reference to FIG. In FIG.
It is assumed that the SD card stores the encrypted data, the decryption key data for decrypting the data, and the accompanying data 217 in which the number of remaining reproduction times is counted. A file name is given to each content of the encrypted data, and a series of data of decryption key data and remaining reproduction count data is present in each content as a pair. That is, the SD card stores such data as many as the contents. The encrypted data, the decryption key, and the remaining reproduction count data are stored in the non-volatile memory. The SD memory reproducing device 212 has a decryption processing unit 213 and a content output unit 214. The SD memory reproducing device 212 is
Further, it has a counter 216. Counter 216
Receives the signal via decryption of the remaining play count data attached to the decryption key, initializes the remaining play count, counts the number of performances of the song, etc. It is possible "will be reported at any time.

First, a read request 215 for specific content is input from outside the SD memory reproducing device 212. Then, the SD memory reproducing device 212 outputs a key request to the card interface controller 202. next,
The card interface controller 202 outputs a key request to the key information recording unit 205. Next, the key information recording unit 205 uses the card interface controller 20.
The key information is output to 2. Next, the card interface controller 202 outputs the key information to the decryption processing unit 213. Further, the card interface controller 202 issues a decryption key request to the protected memory core 204. Next, the protected memory core 20
4 outputs the decryption key and the remaining reproduction count data to the card interface controller 202. Next, the card interface controller 202 outputs the decryption key and the remaining reproduction count data to the decryption processing unit 213. The remaining reproduction count data is set in a counter in the reproducing device.

Next, the SD reproduction device 212 outputs a content request to the card interface controller 202. Next, the card interface controller 2
02 outputs a content request to the memory core 203. Next, the memory core 203 outputs the encrypted content to the card interface controller 202. Next, the card interface controller 202 outputs the encrypted content to the decryption processing unit 213.

In this way, the decryption processing unit 213 decrypts the encrypted content using the decryption key based on the input key information and outputs it to the user via the content output unit 214. That is, the decryption key data in the SD memory card 200 is sent to the decryptor in the external device, the encrypted data is also sent to the decryptor, and the decrypted data is reproduced in the external device one after another. It The data sent out in this manner is converted into music by an external device, becomes game software, becomes book data, and entertains the device user. The numerical value of the counter in the playback device is counted down by one every time one song or one game starts or ends. The numerical value of the counter is transferred to the SD card when another song or game is selected, and is overwritten and saved in the remaining play count data file stored in the memory core.

The method of limiting the number of times of reproduction as described above is described in "Nikkei Electronics 738, pages 94 to 98, 1999.
Issued March 8, 2012 ". Further, a method of limiting the number of times of reproduction and the time limit of reproduction is disclosed in Japanese Patent Laid-Open No.
No. 01-125961 and JP 2001-6779 A.
Japanese Patent Laid-Open No. 2000-3476 discloses a method of counting the number of times of reproduction as a number of times of reproduction after a predetermined time has elapsed.
No. 96 publication and the like. Further, a method of limiting the number of times of reproduction and use in an SD card is disclosed in Japanese Patent Laid-Open No. 2000-
No. 357371. Further, Japanese Patent Laid-Open No. 2000-148945 discloses a technique for automatically deleting unnecessary information in an IC card and effectively utilizing memory resources.

[0014]

The conventional memory card as described above has the following problems.

A problem with the conventional memory card is that the data utilization style of each content differs. For music, the received data is played back in order and used, so there is little problem even if the countdown is made first. However, after listening to it for a while, even if I stopped it immediately, it would have been played once. Also people who want to hear only the first half of the song are in trouble. Books are more difficult. Long novels are rarely read in the same place, and they are read little by little in order, so it is actually once, but the number increases each time the power is turned off.

In this situation, in order to be fair,
There has been a strong demand that it be possible to restrict the reproduction of each content according to the reproduction amount of data. When a counter is provided to count the number of times of reproduction, when a counter is provided to the reproducing apparatus, it is necessary to provide a counter to all the reproducing apparatuses, which is a burden on the reproducing apparatus. Furthermore, even when the memory card body is provided with a counter, the counter becomes large,
This hinders the miniaturization of memory cards.

An object of the present invention is to solve the above problems of the prior art.

It is a particular object of the present invention to provide a small memory card having high security by counting the reproduction state of contents.

Another object of the present invention is to provide a content distribution system and a content distribution method that can count the content according to the amount of reproduced data and that is suitable for the mechanism of content sales.

[0020]

In order to solve the above problems, a memory card according to the first aspect of the present invention comprises an interface for inputting / outputting contents to / from the outside, an interface driver for driving the interface, A card interface controller that inputs and outputs signals to and from this interface driver, a security processing unit that is controlled by this card interface controller, and that supplies an encryption key to the card interface controller when there is a content playback request, and this security processing unit. A memory core interface that is controlled by the card interface controller and that includes a binary counter that counts the playback amount in response to a content playback request, and this memory core interface. Therefore, when the content is written, read, or erased, and the content reproduction request is input, the reproduction amount is recorded for each content, and when the reproduction request does not exceed the reproducible amount, the encrypted content is stored in the memory core. And a memory core for outputting to the interface.

A memory card according to a second aspect of the present invention comprises an interface for inputting / outputting contents to / from the outside, an interface driver for driving the interface, and a card interface controller for inputting / outputting signals to / from the interface driver. , A security processing unit that is controlled by this card interface controller and supplies an encryption key to the card interface controller when there is a content playback request, and is controlled by this security processing unit and the card interface controller, and in response to the content playback request, A memory core interface that includes a binary counter that counts the number of times and calculates the number of times that playback is possible When the content is played, read, and erased, and the content playback request is input, the number of replayable times for each content is recorded. It has a memory core for outputting.

A memory card according to a third aspect of the present invention is an interface for inputting / outputting contents to / from the outside and inputting an automatic erasing signal for contents, an interface driver for driving the interface, and an interface driver and signals for the interface driver. A card interface controller that performs input / output, a security processing unit that is controlled by this card interface controller and that supplies an encryption key to the card interface controller when a content playback request is made, and a security processing unit and a card interface controller that control this security processing unit. , Including a binary counter that counts the playback amount according to the content playback request, and encrypts the encrypted content and the encryption key when an automatic content deletion request is input. The memory core interface that outputs the erase request of the, and the content is written, read, and erased by this memory core interface, and when the content reproduction request is input, the reproduction amount is recorded for each content, and the reproduction request is transmitted. It has a memory core that outputs the encrypted content to the memory core interface when it does not exceed the reproducible amount, and erases the encrypted content and the encryption key when a request to automatically erase the encrypted content and the encryption key is received. Characterize.

A content distribution system according to a fourth aspect of the present invention receives a request for content supply from a user and receives a request approval / disapproval judging means for judging whether or not the request should be permitted, and a judgment result of the request approval / disapproval judging means. When the supply is possible, the content supply means for supplying the content to the memory card, and the judgment result of the request permission / inhibition judgment means, when the supply is possible, the content decryption encryption key with the reproducible amount data is provided to the memory card. And a cryptographic key supply means for supplying.

A content distribution system according to a fifth aspect of the present invention receives a request for supplying a content decryption encryption key from a user and determines whether or not the request should be permitted, and a request permission / inhibition determination means. In response to the determination result of the means, an encryption key supplying means for supplying the content decryption encryption key with the reproducible amount data to the memory card when the supply is possible.

A content distribution system according to a sixth aspect of the present invention comprises means for accepting a request for specification of content to be downloaded and a request for reproducible amount from a user,
A means for providing the user with a supply price according to the specified content and the reproducible amount, and an encryption key for supplying the decryption key with the reproducible amount data specified in the memory card in response to the download confirmation instruction from the user And a supply means.

A content distribution method according to a seventh aspect of the present invention comprises a step of receiving a specification request and a reproducible amount request of a content to be downloaded from a user,
The step of providing the user with the specified content and the supply price according to the reproducible amount, and upon receiving the download confirmation instruction from the user, download the content and the designated decryption key with the reproducible amount data to the memory card. And a step of making

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) An overall structure of a memory card 1 of the present embodiment will be described with reference to FIG. 1 by taking an SD card as an example. Interface (outside terminals: power supply terminal, clock terminal,
A data terminal, a command terminal, etc.) 2 are provided, and a memory core (data storage unit) 3 including a flash memory for storing downloaded information contents is provided inside.
And a control circuit unit including a CPU and the like. Here, in the control circuit unit, a security processing unit (encryption processing circuit) having a security function and an interface driver 4 which is connected to an external terminal and performs signal conversion processing.
5, a card controller 6, a memory core interface 7, and the like are provided. Here, since the control of the flash memory is performed by the control circuit unit, it is not necessary to perform complicated control processing peculiar to the flash memory from outside the card.

Here, the interface 2 inputs and outputs contents with the outside. The interface driver 4 drives the interface 2. Further, the card interface controller 6 inputs and outputs signals with the interface driver 4. The security processing unit 5 is controlled by the card interface controller 6 and supplies an encryption key to the card interface controller 6 when a reproduction request for each content is made. The memory core interface 7 is
Controlled by the security processing unit 5 and the card interface controller 6, the number of times is counted in response to a content reproduction request, and the number of reproducible times is calculated.

The memory core 3 records the number of reproducible times for each content when the content is written, read, and erased by the memory core interface 7 and a content reproduction request is input, and the reproduction request circuit is provided. If the number of times of reproduction is not exceeded, the encrypted content is output to the memory core interface 7.

In order to realize the security function, in addition to the user data area which can be normally accessed, the memory core 3 can be accessed only by the system to which access is permitted by mutual authentication, and the mutual authentication. There is key information used for. When downloading music content to a memory card, the encrypted content is recorded in the user data area. The key information and copy control information used to encrypt this content are stored in the protected area after mutual authentication. The information stored in the protected area is
Only legitimate systems with mutual authentication can be copied. To read the content from the memory card, the key used for encryption is read from the protected area, and the content in the user data area is decrypted using the read key. Data about the limitation of the usage amount of the content is incorporated in the decryption key data.

Next, the decryption key of this embodiment will be described with reference to FIG. This decryption key is recorded in the memory core 3, and its data is updated at the time of reproduction and copying. First, the content name 10 that identifies the content is recorded. Further, the decryption data 11 is recorded. Furthermore, copy status data 12 is recorded. This copy status data 12 is recorded as "1", for example, when the content specified by the content name has already been copied to another SD card, and in this case, the SD card is set as a state in which reproduction is impossible. ing. This is to prevent unlimited unauthorized copying. Further, when the data is not copied to another SD card, "0" is recorded, and it is set in a state in which reproduction is possible if other conditions are satisfied.

Further, the reproduction number limit data 13 is recorded as a part of the decryption key data. Here, if the number of times of reproduction is not limited, for example, "0" is recorded. If the number of playbacks is limited, for example, "1"
Is recorded, and the number of times of reproduction is limited.

Further, the reproducible frequency data 14 is recorded as a part of the decryption key data. The memory core 3 is set so that when the reproducible frequency data records "0", the content is not read even if there is a content reproduction request.

Next, the content reading procedure of the present embodiment will be described with reference to FIG. 3, which is a partial conceptual diagram of the content distribution system. In FIG. 3, the passage of time is shown from top to bottom. In FIG. 3, FIG.
The card interface controller 6 and the memory core interface 7 in the above are collectively referred to as a memory card interface controller 6. First,
The content reproduction device 15 receives a reproduction request 20 for the content downloaded to the memory card 1 by the user. In response to the request 20 to reproduce this content,
The content reproduction device 15 creates the key information request signal 21 in the memory card interface controller 6. Upon receiving the request signal 21, the memory card interface controller 6 transfers 22 the key information request to the security processing unit 5. Security processing unit 5
In response to this transfer 22 of the key information request, the key information is submitted 23 to the memory card interface controller 6. Memory card interface controller 6
Receives the key information submission 23 and receives the content reproduction device 1
The key information is transferred 24 to the key 5.

Next, the content reproducing apparatus 15 makes a request 25 for the decryption key to the memory card interface controller 6. Request this decryption key 25
In response to this, the memory card interface controller 6 transfers the request 26 to the memory core 3. In the protected memory core area, the memory core 3 receives the request transfer 26 and submits the decryption key to the memory card interface controller 6 2
Do 7.

Next, the memory card interface controller 6 transfers 28 the decryption key to the content reproducing apparatus 15. Further, the memory card interface controller 6 performs a process 29 for reducing the number of times that the decryption key information can be reproduced by one.

Next, the content reproduction apparatus 15 makes a request 30 for the encrypted content to the memory card interface controller 6. The memory card interface controller 6 transfers this request to the memory core 3 3
Do 1. Next, the memory core 3 submits the encrypted content to the memory card interface controller 6 3
Do 2. The memory card interface controller 6 transfers the encrypted content to the content reproducing device 3
Do 3. The content reproduction device 15 decrypts 34 the encrypted content. In this way, the content reproduction 35 is performed for the user.

Next, the configuration of the reproducible number countdown circuit included in the memory core interface 7 will be described with reference to FIG. It should be noted that the reproducible number countdown circuit may be installed in the card interface controller 6 without any problem. Decoding key read signal is inverter 4
Input to 0. The countdown signal is input to one input end of the OR circuit 41, and the data read clock signal is input to the other input end of the OR circuit 41. The output signal of the inverter 40 is input to the load signal input terminal of the synchronous up / down 4-bit binary counter 42. The output signal of the OR circuit is input to the clock signal input terminal of the synchronous up / down 4-bit binary counter 42. Content data D0, D1, D2 and D3 are input to the data input terminals A, B, C and D of the synchronous up / down 4-bit binary counter 42, respectively. Receiving these input signals, the synchronous up / down 4-bit binary counter 42 reproduces the number of reproducible times data (LSB) Q0, Q1, Q2, (MSB).
Output Q3.

The up / down signal lines and the enable signal lines P and T are connected to the ground.

A plurality of D-type flip-flops are provided, and the content data D4 and the data reading clock signal are separately input to the data input terminal and the clock input terminal to the first-stage flip-flop 43, and reproduced.
Data Q4 other than the possible number of times is output.

Content data Dn and a data read clock signal are sent to the final stage flip-flop 44.
Each is separately inputted to the data input and a clock input terminal, data Qn non reproducible number is output.

Next, the operation of the reproducible countdown circuit shown in FIG. 4 will be described with reference to the waveform diagram of FIG.
At the timing when the decryption key read signal changes from "L" level to "H" level, for example, the content data D0, D2, D4 change to "0" level and the content data D1, D3, Dn change to "1" level. The state is maintained while the decryption key read signal is in the "H" level after the transition to.

While the decryption key read signal is at "H" level, the data read clock signal transits from "L" level to "H" level for a certain period of time. Data Q1,
All of Q3 and Qn transit from "0" level to "1" level at the timing when the data read clock signal transits from "L" level to "H" level.

After the decryption key read signal transits to the "L" level, the countdown signal transits from the "L" level to the "H" level, and returns to the "L" level after a fixed time. The reproducible data Q1 transits from the "1" level to the "0" level at the timing when the countdown signal transits to the "H" level. At the same timing, the reproducible count data Q0 changes from "0" level to "1".
Transition to level. The data Q2 and Q4 maintain the "0" level. In this way, the numerical outputs Q0 to Q3 of the binary counter are counted down by one count.

By using such a card, the size is very small.
It has features such as light weight, high durability, simple interface, wide range of applications, strong copyright protection function and high speed data transfer. Further, even if the memory card main body is provided with the counter, the counter is downsized, and the downsizing of the memory card can be promoted.

(Second Embodiment) The memory card of the present embodiment has a structure as shown in FIG. 1 as in the first embodiment. Here, the interface 2 is
Input and output contents with the outside. The interface driver 4 drives the interface 2. Further, the card interface controller 6 inputs and outputs signals to and from the interface driver 4. The security processing unit 5 is controlled by the card interface controller 6 and supplies an encryption key to the card interface controller 6 when a reproduction request for each content is made. The memory core interface 7 is controlled by the security processing unit 5 and the card interface controller 6, and counts the reproduction amount of the content in response to a content reproduction request to calculate the reproducible amount.

The memory core 3 records the reproducible amount for each content when the content is written, read, and erased by the memory core interface 7 and a content reproduction request is input, and the reproduction request amount is recorded. If the content does not exceed the reproducible amount, the encrypted content is output to the memory core interface 7.

Further, in order to realize the security function, in addition to the user data area that can be normally accessed, the memory core 3 can be accessed only by the system to which access is permitted by mutual authentication, and the mutual authentication. There is key information used for. When downloading music content to a memory card, the encrypted content is recorded in the user data area. The key information and copy control information used to encrypt this content are stored in the protected area after mutual authentication. The information stored in the protected area is
Only legitimate systems with mutual authentication can be copied.

Next, the decryption key of this embodiment will be described with reference to FIG. This decryption key is recorded in the memory core 3, and its data is updated at the time of reproduction and copying. First, the content name 50 that identifies the content is recorded. Further, the decryption data 51 is recorded. Furthermore, copy status data 52 is recorded. This copy status data 52 is recorded as "1" when the content specified by the content name is already copied to another SD card, and in this case, the SD card is set as a state in which reproduction is impossible. ing. This is to prevent unlimited unauthorized copying. Further, "0" is recorded when it is not copied to another SD card, and it is set to a state where reproduction is possible if other conditions are satisfied.

Further, reproduction capacity limit data 53 is recorded. Here, if the reproduction capacity is not limited, for example, "0" is recorded. If the reproduction capacity is limited, for example, "1" is recorded and the reproduction capacity is set to be limited.

Furthermore, the data 54 of the reproducible data capacity is
Is recorded. When the data of this reproducible data capacity records “0”, the content is not read even if there is a content reproduction request, so that the memory core 3
Is set. Furthermore, the content storage address 5
5 is recorded.

Next, the processing procedure for writing (downloading) contents to the memory card according to the present embodiment will be described with reference to FIG. In FIG. 7, the card interface controller 6 and the memory core interface 7 in FIG. 1 are generically called the card interface controller 6. First, the user requests the content download device 56 to write a content 57.
Enter. Next, the content download device 56
In response to the content write request 57, makes a key information request 58 to the card interface controller 6.
Next, the card interface controller 6
The key information request is transferred 59 to the security processing unit 5 which is a card key information storage unit. Next, the security processing unit 5
For the card interface controller 6,
Submit key information 60.

Next, the card interface controller 6 transfers 61 the key information to the content download device 56. Next, the content download device 56 performs content encryption 62. Then, the content download device 56 submits 63 the encrypted content to the card interface controller 6.

Next, the card interface controller 6 transfers 64 the encrypted content to the memory core 3. Next, the memory core 3 stores the encrypted content 65. Next, the content download device 56 submits 66 the decryption key to the card interface controller 6. Next, the card interface controller 6 stores the content in the decryption key and attaches the address information 67. next,
The memory core 3 stores the decryption key 68.

Next, a procedure for reading contents from the SD card according to the present embodiment will be described with reference to FIG. In FIG. 8, the card interface controller 6 and the memory core interface 7 in FIG. 1 are collectively referred to as the card interface controller 6. First, the user makes a content reproduction request 70 to the content reproduction device 15. Upon receiving the content reproduction request 70, the content reproduction device 15 makes a key information request 71 to the card interface controller 6. Next, the card interface controller 6
The key information request is transferred 72 to the security processing tool 5.
Next, the security processing unit 5 submits 73 the key information to the card interface controller 6.
Next, the card interface controller 6 transfers 74 the key information to the content reproduction device 15. The content reproducing device 15 makes a request 75 for a decryption key to the card interface controller 6. Next, the card interface controller 6
Performs request transfer 76 to the memory core 3. Next, the memory core 3 submits 77 the decryption key in the protected memory core to the card interface controller 6.

Next, the card interface controller 6 transfers the decryption key 78 to the content reproducing apparatus and sets 79 the counter of the reproducible data capacity.

Next, the content reproducing apparatus 15 makes a data request 80 of the encrypted content to the card interface controller 6. The card interface controller 6 determines 81 whether the counter value is 1 or more.

When the judgment 81 of whether the counter value is 1 or more is negative, the contents reproducing apparatus 15 reports the judgment 82 that the reproduction limit is exceeded, and the process ends. 8
3 is done. Card interface controller 6
Is 1 in the judgment 81 of whether the counter value is 1 or more.
When it is determined that the above, for the memory core 3,
A request transfer 84 is performed.

The memory core 3 submits the encrypted content to the card interface controller 6 85.
I do. The card interface controller 6 transfers 86 the encrypted content to the content reproduction device 15 and counts down 87 the counter.

Next, the content reproducing apparatus 15 decrypts 88 the encrypted content, reproduces the content 89 for the user, and makes a data request 80 of the encrypted content to the content reproducing apparatus 15.

As described above, in order to read the content from the memory card, the key used for encryption is read from the protected area, and the content in the user data area is decrypted using the read key. Data about the limitation of the usage amount of the content is incorporated in the decryption key data.

That is, first, the SD card stores the encrypted data, the decryption key data for decrypting the data, and the accompanying data in which the remaining reproduction data amount is counted. A file name is given to each content of the encrypted data, and a series of data of decryption key data and remaining reproduction data amount count data exists in each content as a pair. That is, the SD card stores such data as many as the contents. The encrypted data, the decryption key, and the reproduction residual data amount count data are stored in the flash memory.

In this way, the content data is sent to the playback device one after another, and the value of the counter is set to 1 at the same time.
Decrease by count. Since the countdown clock is a signal generated in synchronization with the data transfer of the encrypted content, the same number of pulses as the data output is generated.

In this way, when the counter becomes "0", a message indicating that the playback limit has been exceeded is sent to the playback device, and the request for content data cannot be issued to the memory core.
The reproduction of the content ends.

In this way, the user enjoys another content. Then, the counter value of the previous content (that is, "0") is written in the reproducible data capacity column of the previous content decryption key.

At this time, the data of the decryption key is erased and then written.

In this way, since the reproduction remaining data amount count data is written in the non-volatile memory, the data is not erased even when the power of the reproduction device is turned off.

Next, according to the procedure starting from the new content reproduction request 70, the reproduction of the new content is started.

By writing the counter value in the reproducible data capacity column of the decryption key at regular intervals, the counter value is stored in the non-volatile memory even when the power is suddenly turned off, and the data is stored. It can be prevented from disappearing.

Also, when switching to another content while enjoying the content, when the data address of the new content is selected, it is detected that the storage address of the content currently enjoyed is different, Write the counter value of the content of No. in the playable data capacity column of the current content decryption key, terminate the current content, and play the new content through the procedure starting from the playback request for another selected content. Begins.

If unencrypted content is recorded in the memory card, the decryption key is not sent to the external device, and only the content data is sent.
It is directly reproduced as reproduction data without being decrypted.

Next, the configuration of the reproducible data capacity countdown circuit included in the memory core interface 7 will be described with reference to FIG. The reproducible data capacity countdown circuit is the card interface controller 6
There is no problem even if installed in. The decryption key read signal is input to the inverter 90. The countdown signal is input to one input terminal of the OR circuit 91, and the data read clock signal is input to the other input terminal of the OR circuit 91. The output signal of the inverter 90 is input to the load signal input terminal of the synchronous up / down 26-bit binary counter 92. The output signal of the OR circuit 91 is a synchronous up / down 26-bit binary counter 92.
Is input to the clock signal input terminal of. Content data D0, D1, D2, D3, ..., D25 are input to the data input terminals A, B, C, D, ..., Z of the synchronous up / down 26-bit binary counter 92, respectively. In response to these input signals, the synchronous up / down 26-bit binary counter 92 has the reproducible data capacity data (LSB) Q0, Q1, Q2.
Outputs Q3, ..., (MSB) Q25.

The up / down signal line and the enable signal lines P and T are connected to the ground.

A plurality of D-type flip-flops are provided, and the content data D26 and the data reading clock signal are separately input to the data input terminal and the clock input terminal to the flip-flop 93 at the first stage, thereby reproducing the reproducible data. Data Q26 other than the capacity is output.

Content data Dn and a data read clock signal are sent to the final stage flip-flop 94.
The data Qn other than the reproducible data capacity is separately input to the data input terminal and the clock input terminal, and output.

Next, the operation of the reproducible data capacity countdown circuit shown in FIG. 9 will be described with reference to FIG. 10 which is a waveform diagram. At the timing when the decryption key read signal transits from the “L” level to the “H” level, for example, the content data D0, D1, D2, D25, D26 transit to the “0” level and the content data D3, Dn to “1”. It is assumed that the state is maintained while transitioning to the "level" and the decryption key read signal is at the "H" level.

While the decryption key read signal is at "H" level, the data read clock signal transits from "L" level to "H" level for a certain period of time. Data Q3,
Qn transits from "0" level to "1" level at the timing when the data read clock signal transits from "L" level to "H" level.

After the decryption key read signal transits to the "L" level, the countdown signal transits from the "L" level to the "H" level and returns to the "L" level after a fixed time. At the timing when the countdown signal transits to the “H” level, the data Q3 of the reproducible data capacity transits from the “1” level to the “0” level. Further, at the same timing, the data Q0 and Q of the reproducible data capacity are
1, Q2 transits from "0" level to "1" level.
The data Q25 and Q26 maintain the "0" level. Thus, the binary counter numerical outputs Q0 to Q
25 is counted down by one count.

Next, the content distribution system of the present embodiment will be described with reference to FIG. 11 showing the conceptual configuration.

The content download device 56 has a request approval / disapproval determination unit 100 that accepts a content supply request from a user and determines whether the request should be permitted.

The content supply unit 101 receives the determination result of the request permission / inhibition determination unit 100 via the interface unit 102 and supplies the content to the memory card 1 when the supply is permitted. If the content is not supplied, the content is not supplied.

Upon receiving the determination result of the request permission / inhibition determination unit 100, the encryption key supply unit 103 supplies the content decryption encryption key with the reproducible amount data to the memory card 1 when the request is acceptable. The content may be stored in the content download device 56, or may be transmitted from the content provider system 105 through the provider 104 via a communication line or the like.

Further, in the download device 56, a receiving unit 106 for receiving a content price payment method designating signal from a user is further provided, and further a certainty judging unit 107 for the particular payment method received is provided, and from this certainty judging unit 107. It is possible to further provide a permission unit 108 that causes the content supply unit 101 and the encryption key supply unit 103 to perform a supply operation when it is determined to be certain. In this case, the certainty determination unit 1
07 may be provided in the provider 104 or the content supplier system 105, and may be transmitted / received to / from the download device 56 via a communication line.

The following system may also be used. That is, when content is recorded in the memory card in advance without sequentially downloading the content and the user scales the content reproduction, the request permission / inhibition determination unit 100 requests the content decryption encryption key supply from the user. Is accepted and it is determined whether the request should be permitted. Upon receiving the determination result of the request permission / inhibition determination unit 100, the encryption key supply unit 103 configures the content distribution system so as to supply the content decryption encryption key with the reproducible amount data to the memory card 1 when the request is possible. You can also In this case, the content supply unit 101
Is unnecessary. Even if the content is downloaded to the memory card in advance, it cannot be reproduced unless the encryption key is obtained, so there is no problem in security.

The content distribution system of this embodiment can also be configured as shown in FIG.
The content specifying request and the reproducible amount request are provided in the receiving unit 110, and the request for specifying the downloaded content and the reproducible amount request from the user are received. Based on the received request, the price providing unit 111 provides the user with a supply price according to the specified content recorded in advance in the download device 15 and the reproducible amount. After this, the content download unit 101
Upon receiving a download confirmation instruction from the user, the memory card 1 is caused to download the specified content. The encryption key supply unit 103 downloads the specified decryption key with the reproducible amount data to the memory card 1.

Even in the case of this system, if the content is previously downloaded to the memory card, only the decryption key will be downloaded to the memory card.

The download price to be provided to the user may be selected and displayed as a fixed price in advance, or may be displayed in the provider 104 or the content distributor system 105 via a communication line. A fee calculation unit is provided so that the price can be changed and displayed according to the cumulative time of download request times of multiple users, the requested amount per unit time, the elapsed time from the start of content release, etc. While maximizing profits for users and content providers, users can receive content at an optimal price in the balance of supply and demand. Of course, the display price can be changed on a daily basis, a weekly basis, or the like.

A payment method receiving unit (not shown) may be provided in the download device 56 to receive a content price payment method designating signal from the user. In this case, a certainty determination unit (not shown) is further provided in the download device 56 to determine the certainty of the particular payment method received. The cryptographic key supply unit 103 is operated when the certainty determination unit determines that the encryption key is certain. With such a configuration, the payment ability of the user can be accurately determined before downloading.
Note that the certainty determination unit can be provided in the provider 104 or the content supplier system 105 connected via a communication line to mutually send and receive user credit information.

Next, the content distribution method of this embodiment will be described with reference to FIG. First, in a request receiving step 115, the download device receives a request for designating a content to be downloaded and a request for a reproducible amount from a user.

Next, in the price extraction step 116,
The supply price according to the specified content and the reproducible amount is searched from the database or calculated based on the calculation formula. That is, the content provider uses the download device to set the content charge for each content requested by the user according to the number of reproducible times desired by the user, and further, the total amount of the line usage charge and the line connection charge. Prompt the user to select the payment method.

Next, in the providing step 117, the extracted price is provided to the user.

Next, in the instruction receiving step 118,
Receives a download confirmation instruction from the user.

Next, in the download step 119, the content and the designated decryption key with the reproducible amount data are downloaded to the memory card. At this time, if the content is previously downloaded to the memory card, only the decryption key is downloaded.

Further, a credit inquiry step 120 is provided between the instruction receiving step 118 and the download step 119 to authenticate the user and conclude a payment contract, deposit or confirm the user's withdrawal account, and make a payment from the user's credit card. Credit inquiry to confirm the possibility,
After confirming any settlement condition such as confirmation of withdrawal from the prepaid card, the content provider can provide the content to the user if the credit is confirmed. In this case, if the credibility cannot be confirmed, the process is terminated or the process returns to the start. Alternatively, the memory card may be provided to the user from the download-only machine after the exclusive content is downloaded from the download-only machine to the memory card and the payment method is determined by any means.

In some cases, it may be permitted to download the contents to the memory card free of charge.
In this case, if the number of times of reproduction is limited instead of allowing unlimited reproduction, it may bring a benefit to the content supplier. Therefore, the present embodiment is effective in such a situation. That is, the number of reproducible times of the content is provided to the user as a sample sample, and if the sample user likes the sample content, the content is paid in return for payment as usual.
This is especially effective when downloading.

As described above, the SD card has been used for explanation, but copy protection (Copy Protect)
Ion) MagicGate memory stick with security function and "Secure Multi"
The security circuit portion of "i Media Card" and the like has the same structure, and the present technology is applicable. That is, the present embodiment can be applied to any recording medium having a function of protecting the security of the content recorded in the memory card.

Note that the contents of this embodiment are not limited to music contents and books, and can be applied to moving images, video images, etc. as the memory capacity increases. Ie newspapers, magazines, comics, movies,
This embodiment can be applied as means for recording game software or the like and replacing recording media such as paper media, video cassettes, and DVDs. Further, the content to be downloaded may be music data recorded on a CD or a digital work recorded on a DVD-ROM or MD.

As the devices used for downloading, personal computers and portable terminals (Portable D
digital assistants (PDAs), high-performance mobile phones, terminals installed at stores such as convenience stores, etc. Information is distributed. The device used for reproduction is a reproduction device for a digital audio signal using a removable memory card, and constitutes an audio system together with an amplifier device, a speaker, a CD player, an MD player, a tuner and the like. Of course, it can also be applied to an audio device of a type such as a portable playback device.

As described above, according to the present embodiment, the amount of data reproduction is counted inside the memory card without recording the cooperation of the external device, the remaining reproduction amount is recorded, and when the predetermined reproduction amount is exceeded, Provide a memory card with a function that automatically disables playback. That is, in the present embodiment, a reproduction data amount is registered in advance in a part of the decryption key, the reproduction data amount is counted when the content is enjoyed, and the memory having a function that cannot be reproduced when the initial registration amount is used up. Provide a card.

Further, the contents can be counted according to the amount of reproduced data, and the system suitable for the contents selling system can be constructed. That is, by providing the memory card of this embodiment, the recording medium can be reused for recording / reproducing / erasing a plurality of kinds of contents a plurality of times, and the price of the recording medium itself is shared by the plurality of contents. Therefore, the distribution price of the content can be reduced. Further, due to the widespread use of memory cards, the manufacturing cost of the memory card main body is reduced, and it becomes possible to download contents in advance and distribute the memory card itself, which has a limited amount of reproduction, as a sample to users for free.

Further, since counting is performed by closing the memory card, it is difficult to trick the counting.
That is, since the content reproduction amount or the number of reproductions is counted in the memory card, the count processing mechanism is finer than the count in the external processing device, and it is difficult to disassemble and adjust the count in an attempt to deceive it. large.

As described above, according to the present embodiment, the same effect as that of the first embodiment is obtained, and further, the amount of reproduction or the number of times of reproduction of the downloaded content is limited, and the limitation is imposed. Since there is a high degree of certainty, it is possible to realize a business that distributes contents at low cost. Furthermore, by setting the amount of playback or the number of playbacks of the content by the user, the distributor allows the download of the content at a price according to the time, so that there is a range of pricing of the content according to the needs of the user. Is possible.

The distributor can allow the content to be downloaded with the reproduction amount or the number of reproductions desired by the user, and can charge the fee according to the reproduction amount, so that the user can be satisfied and this function is provided. Can be more competitive than no distributor system.

(Modification of Second Embodiment) In this modification, the content provider downloads the content to the memory card in advance. The user downloads the decryption key to the memory card when the user purchases the memory card or after the purchase. The user can then play the memory card with a limited playing time. In this modification, it takes communication time to download content via a communication line such as the Internet, and thus it may take a long time to download. On the other hand, in this modification, since the content is downloaded to the memory card in advance, the user does not need to download the time, and the user can easily obtain the memory card with the downloaded content. . Since the data amount of the decryption key is extremely small compared to the content, the time required for downloading is extremely short.

It is to be noted that downloading the content to the memory card in advance is not limited to the content provider, and the user can download the content to the memory card in a short time with a dedicated download machine having a high-speed communication line. May be done. Of course, in this modified example, since a memory card with a security function is used, the content does not have a decryption key on the memory card,
Even if downloaded, it cannot be played back and the copyright of the content is protected.

(Third Embodiment) This embodiment also provides a technique for automatically erasing contents. That is, in the memory card of the first embodiment or the second embodiment, even after the reproduction end of the content, the reproduction remaining data amount count data becomes “0”, and the encrypted data exists. A lot of so-called disposable contents that cannot be used will remain in the SD card. Since the file size of the decryption key data and the reproduction residual data amount count data is small, there is no problem, but the encrypted data is often a huge amount of data, and it is preferable that the data is erased when it becomes disposable.

When writing new data due to the characteristics of the non-volatile memory device in the memory card, it is not possible to overwrite the old data. Therefore, when old data is not used and new data (content) is written in that area. In order to do this, it is necessary to delete the data beforehand. Therefore, check the free space of the memory card before downloading using the Internet, and if there is not enough free space for the content you are about to download, delete unnecessary content beforehand. It is preferable to set.

If the erasing process is not performed before the download, and the content is downloaded on the Internet, the erasing work will be started before the downloading work, and the internet connection time will be longer accordingly. I will end up.

Next, the system for automatically erasing the disposable contents according to the present embodiment will be described with reference to the system conceptual diagram of FIG. As shown in FIG. 14, the SD memory card 121 is connected to the SD card reproducing device 122. Here, the user inputs the content automatic deletion setting request 123 to the SD card reproducing device 122. In the SD card reproducing device 122, the content automatic erasing circuit 124 receives the content automatic erasing setting request 123.
Here, the SD memory card 121 has a card interface controller 125, a memory core 126, and a protect memory area 127. A disposable content generation signal is transmitted from the card interface controller 125 to the SD memory card reproducing device 122. In response to this signal, in the SD memory reproducing device 122, if the automatic content deletion setting is made, SD
A content deletion request is transmitted to the memory card 121.

Card interface controller 12
The memory core 12 receives this content erasing request,
6, the memory core 126 performs an erasing process. Further, the card interface controller 125 issues a decryption key erasing instruction to the protected memory area 127,
The protected memory area 127 erases the decryption key attached to the specific content.

Next, the procedure for automatically erasing the disposable contents according to the present embodiment will be described with reference to the flowchart of FIG. As shown in FIG. 15, the user inputs a content automatic deletion request 130 to the content reproduction device 122 at any timing, and content automatic deletion setting 131 is performed.

At the time of reproducing the content, the decryption key is submitted 132 from the protected memory core 127 to the card interface controller 125.

Card interface controller 12
5 transfers the decryption key 133 to the content reproduction device 122, and sets the counter 134 of the reproducible data capacity. The content reproduction device 122 makes a data request 135 of encrypted content to the card interface controller 125. Next, the card interface controller 125 determines 136 whether the counter value is 1 or more.

When the counter value is 1 or more, request transfer 1
37 to the memory core 126. When the counter value is not 1 or more, the content reproduction apparatus 122 makes a determination 138 as to whether or not automatic erasure is performed. In the case of automatic erasing, the card interface controller 125 makes a request 139 to erase the encrypted content and the decryption key to the memory core 126. In the memory core 126, the encrypted content and the decryption key are erased, and the state is transmitted to the content reproduction device 122. Content reproduction device 1
At 22, the process ends 141.

If the content reproduction device 122 does not perform automatic deletion, the reproduction limit excess report 142 is issued.
Then, the processing ends 141.

When the counter value is 1 or more, the request transfer 137 is received, and the memory core 126 submits the encrypted content 143 to the card interface controller 125. The card interface controller 125 tells the content reproduction device 122 that
The transfer 144 of the encrypted content is performed, and the countdown 145 of the counter is performed. The content reproduction device 122 decrypts the encrypted content 146, reproduces the content 146 to the user, and reproduces the content.
A data request 135 of the encrypted content is made to 2.

Here, since the card interface controller 125 sometimes checks the content of the reproduction remaining data amount count data, when the count data "0" is found, a disposable content deletion request or an automatic deletion request is sent from the external device. If so, unnecessary content data will be automatically deleted by sending a signal to clear the encrypted data of the corresponding content. Further, if the unnecessary data is erased before the internet connection, the internet connection time can be shortened. That is, the countdown controller checks the content of the reproduction residual data count data when a reproduction request is made.

Thus, according to the present embodiment, the disposable content erasing request can be freely set while checking the power condition of the device, so that it is desirable to suppress the battery consumption of the reproducing apparatus or continuously enjoy the content. Sometimes you can put off work.

Furthermore, if the disposable contents are automatically erased when they are no longer needed, it is convenient because the waiting time for erasing becomes unnecessary when storing new contents on the Internet or the like. It eliminates the need to delete unnecessary contents.

Further, the work of clearing the data before downloading new contents is not required, and the work time is shortened.

The above embodiments can be implemented in combination.

[0122]

According to the present invention, it is possible to provide a small memory card having high security by counting the reproduction state of contents.

Further, according to the present invention, it is possible to count the contents according to the amount of reproduced data, and to provide the contents distribution system and the contents distribution method suitable for the mechanism of contents sales.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a memory card according to first to third embodiments of the present invention.

FIG. 2 is a conceptual diagram showing the contents of a decryption key according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing a content reading procedure from the SD card according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram of a reproducible frequency countdown circuit according to the first embodiment of the present invention.

FIG. 5 is an operation waveform diagram of the reproducible frequency countdown circuit according to the first embodiment of the present invention.

FIG. 6 is a conceptual diagram showing the contents of a decryption key according to the second embodiment of the present invention.

FIG. 7 is a flowchart showing a procedure for writing content to an SD card according to the second embodiment of the present invention.

FIG. 8 is a flowchart showing a content reading procedure from an SD card according to the second embodiment of the present invention.

FIG. 9 is a configuration diagram of a reproducible frequency countdown circuit according to a second embodiment of the present invention.

FIG. 10 is an operation waveform diagram of the reproducible frequency countdown circuit according to the second embodiment of the present invention.

FIG. 11 is a configuration diagram of an example of a content distribution system according to a second exemplary embodiment of the present invention.

FIG. 12 is a configuration diagram of another example of the content distribution system according to the second exemplary embodiment of the present invention.

FIG. 13 is a flowchart showing a content distribution method according to the second embodiment of the present invention.

FIG. 14 is a conceptual diagram of a system for automatically erasing contents according to the third embodiment of the present invention.

FIG. 15 is a flowchart showing an automatic content deletion procedure according to the third embodiment of the present invention.

FIG. 16 is a conceptual diagram of a system for writing contents to a conventional SD memory card.

FIG. 17 is a conceptual diagram showing the contents of a conventional decryption key.

FIG. 18 is a conceptual diagram of a system for reading contents from a conventional SD memory card.

[Explanation of symbols]

1, 121 SD memory card 2, 102 interface unit 3, 126 memory core 4 interface driver 5 security processing unit 6, 125 card interface controller 7 memory core interface 10, 50 content name 11, 51 decryption data 12,52 copy status data 13 Reproduction Count Limit Data 14 Reproducible Count Data 15 Content Reproduction Device 40, 90 Inverter 41, 91 OR Circuit 42 Synchronous 4-bit Up / Down Binary Counter 43, 44, 93, 94 D Type Flip-Flop 53 Reproduction Capacity Limit Data 54 Reproduction Data of possible data capacity 55 Content storage address data 56 Content download device 92 Synchronous 26-bit up / down binary counter 100 Request approval / disapproval Part 101 Content supplying part 103 Encryption key supplying part 104 Provider 105 Content provider system 106, 110 Accepting part 107 Certainty determining part 108 Permitting part 111 Price providing part 122 SD playback device 123 Content automatic erasing request 124 Content automatic erasing circuit 127 Protect Memory area

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G06K 17/00 G06K 17/00 LT 19/00 19/00 R 19/10 QF term (reference) 5B014 EB05 FB03 GD05 GD23 GD35 5B017 AA03 BB10 CA14 CA16 5B035 AA13 BB09 BC00 CA11 CA29 5B058 CA23 CA25 KA01 KA04 KA31 KA35 5B065 BA09 CC08 PA04 PA16

Claims (8)

[Claims] 1. An interface for inputting and outputting contents to and from the outside, an interface driver for driving the interface, a card interface controller for inputting and outputting signals to and from the interface driver, and contents controlled by the card interface controller. It includes a security processing unit that supplies an encryption key to the card interface controller when there is a reproduction request, and a binary counter that is controlled by this security processing unit and the card interface controller and counts the reproduction amount in response to a content reproduction request. The memory core interface and this memory core interface writes, reads, and erases content and inputs content playback requests. Record the regeneration amount for each content in the case that the memory card to which the playback request and having a memory core and outputting the encrypted content to the memory core interface if not exceeding the amount of renewable. 2. An interface for inputting / outputting contents to / from the outside, an interface driver for driving the interface, a card interface controller for inputting / outputting signals to / from the interface driver, and contents controlled by the card interface controller. The security processing unit that supplies the encryption key to the card interface controller when a playback request is made, and the security processing unit and the card interface controller control it. A memory core interface that includes a binary counter to calculate and this memory core interface writes, reads, and erases content, and When a content playback request is input, the number of playable times for each content is recorded, and if the playback request circuit does not exceed the number of playable times, the memory core outputs the encrypted content to the memory core interface. And a memory card. 3. An interface for inputting / outputting content to / from the outside and inputting a content automatic erasing signal, an interface driver for driving the interface, and a card interface controller for inputting / outputting signals to / from the interface driver, A security processing unit which is controlled by the card interface controller and supplies an encryption key to the card interface controller when a content reproduction request is made, and a security processing unit which is controlled by the security processing unit and the card interface controller and reproduces the content reproduction request. A memory core in that includes a binary counter that counts the amount and outputs an erase request for encrypted content and an encryption key when an automatic content erase request is input. Interface, this memory core interface writes, reads, and erases content, records the playback amount for each content when a content playback request is input, and when the playback request does not exceed the reproducible amount. A memory card, comprising: a memory core that outputs encrypted content to a memory core interface, and that erases the encrypted content and the encryption key when a request to automatically erase the encrypted content and the encryption key is received. 4. A content availability request means for accepting a content supply request from a user and determining whether the request should be permitted, and a content to be stored in a memory card when the content is available, in response to the result of the request availability determination means. And a cryptographic key supply means for receiving a cryptographic key for decrypting the content-attached content data to the memory card when the supply is possible, in response to the determination result of the request propriety determination means. Characteristic content distribution system. 5. A request acceptance / rejection determining means for accepting a content decryption encryption key supply request from a user and determining whether or not the request should be permitted, and a request acceptance / rejection determining means for determining whether or not the request is acceptable. And a cryptographic key supply means for supplying a cryptographic key for decrypting content with reproducible amount data to the memory card. 6. A means for receiving a specification request and a reproducible amount request of a content to be downloaded from a user, a means for providing a supply price according to the specified content and a reproducible amount to the user, and A content distribution system, comprising a cryptographic key supply means for receiving a download confirmation instruction and supplying a decryption key with a reproducible amount data designated to a memory card. 7. A means for accepting a content price payment method designating signal from a user, a means for judging the certainty of a particular payment method received, and the above-mentioned method when the certainty judgment means determines that the certainty is secure. The content distribution system according to any one of claims 4 to 6, further comprising permission means for operating the encryption key supply means. 8. A step of accepting a request for specifying a content to be downloaded and a request for a reproducible amount from the user, a step of providing the user with the specified content and a supply price according to the reproducible amount, and from the user Receiving a download confirmation instruction from the user and downloading the content and the designated decryption key with the reproducible amount data to the memory card.