WO2001069842A1

WO2001069842A1 - Contents reproducing device

Info

Publication number: WO2001069842A1
Application number: PCT/JP2001/002003
Authority: WO
Inventors: Takashi Tsunehiro; Kunihiro Katayama; Nagamasa Mizushima; Takashi Totsuka; Hiroyuki Mano; Kazuo Nakamura; Shigeo Todoroki; Toshiaki Hioki; Takahisa Hatakeyama
Original assignee: Hitachi,Ltd.; Nippon Columbia Co.,Ltd.; Sanyo Electric Co.,Ltd.; Fujitsu Limited
Priority date: 2000-03-14
Filing date: 2001-03-14
Publication date: 2001-09-20
Also published as: TW515950B; AU2001241131A1

Abstract

A license key provided for each element of contents data is stored in a key-only storing device provided separately from a contents storing device; the key-only storing device performs an authentication processing on a communicating partner, and, when authenticated, sends a license key corresponding to contents data to be reproduced to a reproducing device using an encrypted communication, whereby the reproducing device decodes the contents data to be reproduced using the license key and reproduces it.

Description

TECHNICAL FIELD The present invention relates to a technology for permitting only a rightful person to reproduce content data such as audio data and video data, and in particular, can reproduce a large amount of content data. The present invention relates to technology suitable for a simple stationary content reproducing apparatus. BACKGROUND ART In recent years, attempts have been made to distribute content data such as audio data and video data via a network. For example, a dedicated memory card is prepared, attached to a dedicated terminal installed at a store, etc., and the desired content data is downloaded to the memory card using an online system. Alternatively, a dedicated memory card is attached to a personal terminal such as a mobile phone, and the content is delivered from the content distribution center to the memory card using the Internet. When playing back content, the memory card storing the content data is attached to a dedicated playback device and played back. DISCLOSURE OF THE INVENTION Now, a system comprising the above-mentioned dedicated memory force and a playback device In this case, since content can be easily copied, it is necessary to protect the content creator by providing a copy protection function on a dedicated memory card for storing the content. .

However, a memory card cannot store a large amount of content overnight because of its limited capacity. In some cases, users may want to keep a collection of content that is not currently being used. In this case, if the memory card is provided with a copy protection function, the user must purchase a new memory card every time the memory card becomes full of content data, which imposes an economic burden. large.

In addition, when the user wants to play back the content data stored as a collection, the user finds a memory card storing the content data to be played from a large number of memory cards, and uses a dedicated playback device. Must be attached to Each time the memory card storing the content to be played changes, the memory card attached to the playback device must be changed.

Such a system consisting of a memory card with a copy protection function and a playback device is suitable for portable use, but for example, a stationary type that can enjoy content playback overnight at home. Not suitable for

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for reproducing a large amount of content data without exchanging a memory card while protecting the content creator. Is to do.

In order to solve the above problems, the content reproducing apparatus of the present invention reproduces content data encrypted with a different key for each content or each group of the data. The key for decrypting the encrypted content data, which is prepared for each content data group or the data group, is a content storage for storing the encrypted content data. It is stored in storage means with a calculation function provided separately from the means.

Here, the key storage unit with the calculation function has an authentication unit for authenticating the communication partner, and performs encryption communication when the reproduction unit of the content reproduction device is authenticated as the communication partner by the authentication unit. The key corresponding to the encrypted content to be reproduced is transmitted to the reproducing means by using the key. In addition, the reproducing means uses the encrypted content data to be reproduced, read from the content storing means, by using a key transmitted from the key storing means with calculation function using cryptographic communication. Decrypt and play.

In the present invention, since the content data stored in the content storage means is encrypted, it cannot be decrypted and reproduced without the corresponding key. Therefore, it is not necessary to provide a special function such as a copy protection function in the content storage means, so that a large-capacity hard disk device or the like which is generally commercially available can be used as the content storage means. For this reason, a large amount of content data can be stored.

In addition, since a corresponding key is required to decrypt the content data stored in the content storage means, if the key is not stored in the key storage unit with a calculation function, the content data is not stored. Cannot be played. Therefore, only the rightful right holder (the person who has the corresponding key) can be permitted to reproduce the content data overnight, and the content creator can be protected.

Further, in the present invention, the decryption of the encrypted content data is performed by the reproducing means for reproducing the content data. Then, the key storage unit with the calculation function, when authenticating that the transmission destination of the key is the reproduction unit, sends the key to the reproduction unit using encrypted communication. By doing so, the possibility of the key leaking to the outside can be further reduced, and the security can be improved. In general, the size of the key for decrypting the encrypted content data is significantly smaller than the size of the key of the encrypted content data. For this reason, even if a memory card having a copy protection function as described in the related art, which is configured to be attachable to the content reproducing apparatus, is used as the key storage means with a calculation function, Can store a large number of keys corresponding to a large amount of content in a storage device, thus preventing frequent occurrences of having to change memory cards when changing the content to be played back. In addition, it is possible to provide a content reproducing apparatus suitable for a stationary type in which content data can be reproduced in a house. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a schematic configuration of a content reproducing apparatus to which one embodiment of the present invention is applied.

FIG. 2 is a diagram showing a schematic configuration of the key storage device 14 shown in FIG. FIG. 3 is a diagram showing a schematic configuration of the audio reproducing device 18 shown in FIG.

FIG. 4 is a diagram showing a schematic configuration of the video playback device 19 shown in FIG. FIG. 5 is a diagram showing an example of an overview of a content reproducing apparatus to which an embodiment of the present invention has been applied.

FIG. 6 is a flowchart for explaining the playback operation of the content playback device to which the first embodiment of the present invention has been applied.

FIG. 7 is a sequence diagram for explaining an example of data exchange between the key storage dedicated device 14 and the audio playback device 18 / video playback device 19 in the flow shown in FIG. FIG. 8 is a flow chart for explaining an operation when a license key is obtained from the memory card 30 connected to the content reproduction device to which the first embodiment of the present invention is applied. .

FIG. 9 is a sequence diagram for explaining an example of a data exchange between the dedicated key storage device 14 and the memory card 30 in the flow shown in FIG.

FIG. 10 shows an operation when the license key is transferred from the key storage device 14 of the content reproduction device to which the embodiment of the present invention is applied to the memory card 30 connected to the content reproduction device. It is a flow diagram for explanation. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, one embodiment of the present invention will be described.

FIG. 1 is a diagram showing a schematic configuration of a content reproducing apparatus to which an embodiment of the present invention is applied.

In FIG. 1, CPU 11 comprehensively controls each section of the content reproducing apparatus. The memory 12 is composed of ROM and RAM. R〇M stores a program for the CPU 11 to control each part of the content reproducing apparatus in an integrated manner. The RAM functions as a work area for the CPU 11.

The content storage device 13 is composed of a large-capacity storage device such as a hard disk device, for example, and content such as encrypted audio data and video data is associated with the content name. Stored.

The dedicated key storage device 14 is an encrypted content prepared for each content. Stores a key (hereinafter referred to as license key) for decrypting content.

The communication device 15 is connected to a mobile phone or a stationary phone, and distributes, for example, encrypted content data and a license key via a network such as an online system or the Internet. It is used to access a content distribution center (not shown) and obtain an encrypted content data license key.

The input device 16 is composed of, for example, various buttons and a touch panel, and receives a reproduction instruction from a user, an instruction to obtain content data, and a license key.

The display device 17 is composed of, for example, a liquid crystal panel, and displays a list of the content names of the encrypted content data stored in the content storage device 13 and encrypts the playback target. Displays the content name of the content data.

The audio reproducing device 18 reads out the encrypted audio data to be reproduced from the content storage device 13 and decrypts and reproduces it using the corresponding license key to obtain an audio signal. Then, the video playback device 19 outputs the audio signal to a stereo connected to the content playback device. The video playback device 19 reads the encrypted video data to be played back from the content storage device 13 and outputs the read video signal. The video signal is obtained by decrypting and reproducing using the license key corresponding to. Then, the video signal is output to a monitor connected to the content reproducing apparatus.

The card connection device 20 connects the memory card 30 and obtains an encrypted content data or a license key from the memory card 30. The memory card 20 is encrypted. Or send encrypted content data or license keys. The interface 21 controls transmission and reception of data between the CPU 11 and the memory 12 and other devices constituting the content reproducing apparatus.

Next, among the devices constituting the present content playback device, the key storage dedicated device 14, the audio playback device 18 and the video playback device 19 will be described in further detail.

First, the key storage device 14 will be described.

FIG. 2 is a diagram showing a schematic configuration of the key storage dedicated device 14.

As shown in the figure, the key storage device 14 is composed of CPU 14 1 and memory 1

4, a flash memory 144, and an I / O circuit 144 for transmitting and receiving data to and from each section of the content reproducing apparatus via the interface 21.

The CPU 141 controls the components of the key storage device 14 in an integrated manner. Further, the CPU 141 has an authentication function and an encryption / decryption function. The memory 144 is composed of ROM and RAM. The ROM stores a program for the CPU 141 to control each part of the dedicated key storage device 14 as a whole, and a program for implementing the authentication function and the encryption / decryption function. The RAM functions as a work area of the CPU 141. The license key is stored in the flash memory 144 in association with the content name of the content to be decrypted. Here, the license key should be stored in a so-called tamper resistant area (TRM: Tamper Resistant Module) in order to strengthen security. Note that, in place of the flash memory 144, another nonvolatile memory such as FRAM and EPROM can be used.

Each part constituting the dedicated key storage device 14 shown in FIG. 2 may be built on one chip, for example, or may be made up of a plurality of chips. When using multiple chips, the key storage It is preferable to take measures to prevent a signal between chips from being stolen from the outside of the device 14.

Next, the audio reproducing device 18 will be described.

FIG. 3 is a diagram showing a schematic configuration of the audio reproducing device 18.

As shown in the figure, the audio playback device 18 transmits and receives data to and from each section of the content playback device via an encryption / decryption circuit 181, a decoder circuit 182, and an interface 21. And an I / O circuit 184 for performing the operation. The encryption / decryption circuit 18 1 obtains the license key corresponding to the encrypted audio data to be reproduced from the key storage device 14, and uses this key to generate the content storage device 1. Decrypt the encrypted audio data to be reproduced read from step 3. The decoder circuit 182 expands the audio data decoded by the decoding circuit 181 as necessary and reproduces the audio data to obtain an audio signal. Then, the audio signal is output to stereo.

Next, the video playback device 19 will be described.

FIG. 4 is a diagram showing a schematic configuration of the video playback device 19.

As shown in the figure, the video playback device 19 reproduces the present content via a decoding circuit 191, a decoder circuit 1992, a frame buffer 1993, and an interface 21. It has a 1/0 circuit 194 for transmitting and receiving data to and from each part of the device.

The encryption / decryption circuit 191 obtains the license key corresponding to the encrypted video data to be reproduced from the key storage device 14 and uses this key to transmit the license key from the content storage device 13. It decrypts the read encrypted video data to be reproduced. The decoder circuit 182 uses the frame buffer 193 to expand and reproduce the video data decoded by the encryption / decryption circuit 181 as necessary, and reproduce the video signal. obtain. And the video signal Output to monitor.

Next, the memory card 30 used by being attached to the present content reproducing apparatus will be described.

The schematic configuration of the memory card 30 is the same as the key storage device 14 shown in FIG. However, the memory card 30 stores not only the license key but also the encrypted content. That is, the memory card 30 is mounted on a dedicated terminal installed in, for example, a store, and allows a user to use an online system to obtain a desired encrypted content and its license key. The user obtains or encrypts the desired encrypted content data and its license key from the content distribution center by using the Internet or by attaching it to a personal terminal such as a mobile phone. Or it can be used to obtain it.

Here, FIG. 5 shows an example of an overview of a content reproducing apparatus to which the present embodiment is applied. As shown in the figure, the content reproducing apparatus has a stationary shape suitable for enjoying content at home. Here, reference numeral 41 denotes a play button, a stop button, a play content selection button, and the writing of content data and a license key to the content storage device 13 and the key storage device 14, and a card connection device 30. An operation panel including various setting buttons for moving to a memory card 20 connected to the PC. Reference numeral 42 denotes a receiving unit for receiving an instruction from a remote controller 50 having the same various buttons as the operation panel 41. Reference numeral 43 denotes a display panel, which displays a list of content names of the content stored in the content storage device 13 and a content name of the encrypted content to be reproduced. Or display. Reference numeral 44 denotes a slot for mounting the memory card 30. Although not shown, a monitor 51 and a stereo Terminals are provided for connecting the phone 52, the mobile phone 53 or the phone.

Next, the operation of the content reproduction device of the present embodiment will be described. First, the operation in the case where the content is reproduced overnight will be described. FIG. 6 is a flow chart for explaining a reproducing operation of the content reproducing apparatus to which the present embodiment is applied. This flow is, for example, when the user uses the input device 16 to display a list of the content names of the content data stored in the content storage device 13 displayed on the display device 17. It starts when the user selects the content to be played and inputs the playback instruction.

First, the CPU 11 reproduces the content reproduction instruction received from the user via the input device 16 and reproduces the type of the content data (audio data / video data). The data is transmitted to the audio reproducing device 18 / video reproducing device 19 (S1001).

The audio decryption circuit 18 1/19 1 of the audio playback device 18 / video playback device 19 which receives the playback instruction from the CPU 11 1 sends its own authentication data and the encrypted content to be played back. A license key transmission instruction including the identification information (for example, the name of the content) for reproducing the content is transmitted to the key storage device 14 (S1002).

When receiving the license key transmission instruction for reproducing the content data, the CPU 14 1 of the key storage dedicated device 14 performs verification using the authentication data included in the instruction (S 1003). ). For example, it is checked whether or not the authentication data indicates that the device is a video / video playback device registered in the dedicated key storage device 14 in advance. If it is authenticated that the transmission source of the instruction is the audio playback device 18 / video playback device 19 (in the case of Yes in S104), the identification information included in the instruction is used. It is checked whether or not the license key for the identified content is stored in the flash memory 144 (S1005). If the license key is stored (Yes in S106), the license key is read out from the flash memory 144, and the audio playback device 1 which is the transmission source of the instruction is transmitted using encrypted communication. 8 / Send to the video playback device 19 (S1008).

If it is not possible to authenticate that the transmission source of the instruction is the audio playback device 18 / video playback device 19 in S104, and if the desired license key is stored in the flash memory 1 in S106, If it is not stored in 43, the CPU 14 of the key storage device 14 informs the CPU 11 accordingly. In response, the CPU 11 performs a predetermined error process such as displaying an error on the display device 17 (S1007).

By the way, the encryption / decryption circuit 18 1/19 1 of the audio playback device 18 / video playback device 19 which has transmitted the license key transmission instruction for content data playback receives a license from the key storage dedicated device 14. When the sense key is received, the encrypted content data to be reproduced is read out from the content storage device 13 (S109). Then, it is decrypted with the license key and passed to the decoder circuit 182/192. The decoder circuit 18 2/19 2 expands the content data received from the encryption / decryption circuit 18 1/19 1 as necessary, reproduces it to obtain audio / video data, and sends it to the stereo / monitor. Output (S1010).

Next, an example of an exchange of data between the key storage dedicated device 14 and the audio reproduction device 18 / video reproduction device 19 in the mouth shown in FIG. 6 will be described.

FIG. 7 is a sequence diagram for explaining an example of data exchange between the key storage dedicated device 14 and the audio playback device 18 / video playback device 19 in the flow shown in FIG. The decryption circuit 18 1/191 of the audio playback device 18 / video playback device 19 determines its own authentication data and the encrypted content to be played back in S102 of FIG. Evening identification information and the media class secret key K _PMC and the media class public key K paired in advance. _A license key transmission instruction including the _MC is created and transmitted to the key storage dedicated device 14 (T1001).

In response to this, the CPU 14 1 of the key storage device 14 authenticates the audio playback device 18 and the video playback device 19 in S 1004 to S 1007 in FIG. It is confirmed that the requested license key is stored in the memory 143 (T1002). Then, the CPU 14 1 generates a session key K _S1 (T ₁₀₀₃₎ , encrypts this with the media class public key K _QMC included in the license key transmission instruction, and To the audio playback device 18 / video playback device 19, which is the source of the transmission (T1004).

In response to this, the encryption / decryption circuit 18 1/191 of the audio playback device 18 / video playback device 19 has a media class that holds the encrypted session key K _S1 in advance. Decryption is performed using the secret key K _PMC to obtain a session key K _S1 (T1005). Then, a random number K _S2 is generated (T 1 0 6), encrypted with the session key K _{S 1} , and transmitted to the key storage device 14 (T 1 0 7) o

In response to this, CPU 1 4 1 key storage dedicated device 1 4, the random number K _S2 encrypted, decrypted by the session key K _{S 1,} to obtain a random number _{K S2 (T 1 00 8)} . Then, the license key K _e being requested to transmit and encrypted by the random number K _S2, and transmits to the Odo reproducing apparatus 1 8 / video reproducing apparatus 1 9 which is the source of the license key transmission instruction (T 1 0 0 9).

In response, audio playback device 18 / video playback device 19 Three

13

Goka circuit 1 8 1/1 9 1, the encrypted license key K _c is decrypted using the random number K _{S 2,} to obtain a license key _{K e (T 1 0 1 0} ).

The operation for reproducing the content data has been described above. Next, an operation when a license key is obtained from the memory card 30 will be described.

FIG. 8 is a flowchart for explaining the operation when the license key is obtained from the memory card 30 connected to the content reproduction apparatus to which the present embodiment is applied. This flow is performed, for example, in a state where the memory card 30 is attached to the present content reproducing apparatus, and the user uses the input device 16. The memory card 30 displayed on the display device 17 is stored in the memory card 30. It is started when the user selects the content corresponding to the license key to be obtained from the list of content names corresponding to the license key in question, and inputs a license key acquisition instruction.

First, upon receiving a license key acquisition instruction from the user via the input device 16, the CPU 11 transmits the fact to the key storage device 14 (S 200 1) o

The CPU 14 of the dedicated key storage device 14 that has received the license key acquisition instruction from the CPU 11 transmits its own authentication data and identification information of the license key to be obtained (for example, content that can be decrypted with the key). ) Is transmitted to the memory card 30 connected to the card connection device 20 (S2002).

Upon receiving the license key transmission instruction for obtaining the license key, the CPU of the memory card 30 performs verification using the authentication data included in the instruction (S2003). For example, it is checked whether or not the authentication data indicates that it is a key storage device registered in the memory card 30 in advance. Then, the transmission source of the instruction is the key storage dedicated device 14. (In the case of Yes in S204), it is determined whether the license key specified by the identification information included in the instruction is stored in the memory card 30 or not. Examine (S205). If it is stored (Yes in S2006), the license key is read out and transmitted to the dedicated key storage device 14 which is the transmission source of the instruction using the encrypted communication (S2 0 0 8). Then, the transmitted license key is erased from the memory card 30 (S209).

Note that if it is not possible to authenticate that the transmission source of the instruction is the dedicated key storage device 14 in S 2004, and that the desired license key is stored in the memory card 30 in S 2006. If not, the CPU with memory card 30 informs CPU] 1. In response to this, the CPU 11 performs predetermined error processing such as displaying an error on the display device 17 (S207).

Now, the CPU 14 1 of the key storage device 14 that has transmitted the license key transmission instruction for obtaining the license key receives the license key from the memory card 30 connected to the card connection device 20. This is stored in the flash memory 144 in association with, for example, the content name of the content data that can be decrypted with the key (S210).

Next, an example of data exchange between the key storage device 14 and the memory device 30 in the flow shown in FIG. 8 will be described.

FIG. 9 is a sequence diagram for explaining an example of data exchange between the key storage dedicated device 14 and the memory card 30 in the flow shown in FIG.

In S202 of FIG. 8, the CPU 141 of the key storage device 14 determines its own authentication data, the identification information of the license key to be obtained, and the media class secret key K ′ held in advance. Media class public key paired with _PMC Κ ' ₀ CT / JP01 / 02003

Fifteen

_A license key transmission instruction including the _MC is created, and this is transmitted to the memory card 30 (T2001).

In response to this, the CPU of the memory card 30 is required to authenticate the key storage device 14 and to request the memory card 30 from S204 to S207 in FIG. Confirm that the license key is stored (T202). Then, the CPU of the memory _{card 30} generates a session key K _sl (T ₂₀₃ ), and encrypts it with the media class public key K ′ _0MC included in the license key transmission instruction. It is transmitted to the key storage device 14 which is the transmission source of the instruction (T20004).

In response to this, the CPU 14 1 of the key storage device 14 decrypts the encrypted session key K _s i with the media class secret key K ′ _P M _c that holds the session key K _s i in advance. Obtain the key K _{S 1} (T 2 0 5). Then, a random number K _{S 2} is generated (T 2 0 6), and this is _stored in a session with a _{previously stored} media unique private key Κ, _{Ρ Μ} and a pair of media unique public key Κ ′ 0 _対 . The data is encrypted with the key K _S1 and transmitted to the memory card 30 (T207).

In response to this, the memory card 3 0 of the CPU, the encrypted random number K _{S 2} and media-specific public key K _'0M, decrypted by session key K _{S 1,} the random number K _S2 and media-specific Obtain the public key _K'0M ( _T2008 ). Then, 'encrypted with _0MC, further this random number K' the license key K _c which is requested to send media § unique public key K encrypted with _S2, the key storage that is the source of the license key transmission instruction The data is transmitted to the dedicated device 14 (T209).

In response to this, the CPU 14 1 of the key storage dedicated device 14 decrypts the encrypted license key Kc using the random number K _{S 2} and the media-specific secret key K ′ _PM , and obtains the license key K _c Get (T2 0 10).

The operation when the license key is obtained from the memory card 30 has been described above. Next, an operation when the license key stored in the key storage dedicated device 14 of the present content reproducing apparatus is moved to the memory card 30 will be described.

FIG. 10 shows an operation when the memory card 30 connected to the content playback device is moved from the key storage device 14 of the content playback device to which the present embodiment is applied. It is a flowchart for the description. This flow is, for example, a key storage device that is displayed on the display device 17 by the user using the input device 16 in a state where the memory card 30 is mounted on the content reproducing device. Start by selecting the content corresponding to the license key to be moved from the list of content names corresponding to the license key stored in 14 and inputting the license key transfer instruction. When receiving the license key movement instruction from the user via the input device 16, the CPU 11 transmits the effect to the memory card 30 (S 3001).

The CPU of the memory card 30 that has received the license key transfer instruction from the CPU 11 transmits its own authentication data and the identification information of the license key to be moved (for example, the content of the content that can be decrypted with the key). A license key transmission instruction for moving the license key including the name is transmitted to the key storage dedicated device 14 (S3002).

Upon receiving the license key transmission instruction for moving the license key, the CPU 1441 of the key storage device 14 performs verification using the authentication data included in the instruction (S3003). ). For example, it is determined whether or not the authentication data indicates that the memory card 30 is registered in the dedicated key storage device 14 in advance. Then, if it is authenticated that the transmission source of the instruction is the memory card 30 (in the case of Yes in S304), the license specified by the identification information included in the instruction Key is a flash memo It is checked whether it is stored in the memory 144 (S 305). If it is stored (Yes in S3006), the license key is read out. It is transmitted to the memory card 30 that is the transmission source of the instruction by using cryptographic communication (S 3 0 8). Then, the transmitted license key is deleted from the flash memory 144 (S3009).

If the sender of the instruction cannot be authenticated to be the memory card 30 in S 304, and the desired license key is stored in the flash memory 144 in S 300 6 If not, the CPU 14 1 of the key storage device 14 informs the CPU 11 accordingly. In response to this, the CPU 11 performs predetermined error processing such as displaying an error on the display device 17 (S3007).

When the CPU of the memory card 30 that has transmitted the license key transmission instruction for moving the license key receives the license key from the key storage device 14, the CPU that can decrypt the license key with the key, for example. It is stored in the memory card 30 in association with the content name of the content data (S31010). In addition, between the key storage dedicated device 14 and the memory card 30 in the port shown in FIG. This data exchange is the exchange of the operations of the key storage device 14 and the memory card 30 in the sequence diagram shown in FIG.

The operation when the license key is moved to the memory card 30 has been described above.

In addition, using a mobile phone / stationary phone connected to the communication device 15, a content delivery center (not shown) is connected via an online system or a network such as an internet connection. The operation of obtaining a license key may be the same as a general download over the network. However, only those who have legitimate rights can obtain the license key. Authentication process between the dedicated key storage device 14 and the content distribution center to download the license key only when the content distribution center has authenticated the key storage dedicated device 14. It is preferable to allow In addition, the download of content data to the content storage device 13 may be performed by, for example, copying the content stored in the memory card 30 and storing it in the content storage device 13. Or using a mobile phone / stationary phone connected to the communication device 15 to access the content via a network such as an online system or Internet connection. It may be obtained from a distribution center (not shown) and stored in the content storage device 13. In any case, the content is encrypted and cannot be decrypted or played without a corresponding license key.

Hereinabove, one embodiment of the present invention has been described.

In this embodiment, since the content stored in the content storage device 13 is encrypted, it cannot be decrypted and reproduced without the corresponding license key. Therefore, it is not necessary to provide a special function such as a copy protection function in the content storage device 13, and a generally available large-capacity hard disk device or the like can be used as the content storage device 13. . Therefore, it is possible to store a large amount of content overnight.

In addition, since a corresponding license key is required to decrypt the content data stored in the content storage device 13, the license key must be stored in the key storage device 14. The content day cannot be played. Therefore, it is possible to permit only a rightful right holder (a person who has a corresponding license key) to reproduce the content data overnight, thereby protecting content authors and the like. Further, in the present embodiment, the decryption of the encrypted content data is performed by the audio playback device 18 / video playback device 19 for playing back the content overnight. Then, if the key storage dedicated device 14 authenticates that the license key transmission destination is the audio playback device 18 / video playback device 1, the key storage dedicated device 14 uses the encryption key to transmit the license key using encryption communication. Video playback device 18 / video playback device 19. By doing so, the possibility of the license key leaking to the outside can be further reduced, and the security can be improved.

In addition, in the present embodiment, when the license key transmission destination is the memory card 30, the key storage device 14 deletes the transmitted license key from the stored contents of the key storage device 14. I am trying to do it. That is, the key storage device 14 is provided with a license key copy protection function. In this way, the likelihood of unauthorized copying of the license key can be reduced.

In general, the key data size is significantly smaller than the data size of the encrypted content data. Therefore, even when the storage unit of the key storage device 14 is constituted by the flash memory 144, many license keys can be stored in the flash memory 144. Therefore, it is possible to provide a content reproducing apparatus suitable for a stationary type in which content data can be reproduced in a house.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the gist.

For example, the above embodiment has been described taking as an example a case where the encrypted content data is stored in the content storage device 13 which is a storage device such as a hard disk device. However, the present invention is not limited to this. The encrypted content file is D It may be provided in a form stored in a portable storage medium such as a VD or a CD. In this case, in the present embodiment, a reading device that reads encrypted content data from the portable storage medium may be provided instead of the content storage device 13.

Further, in the above embodiment, the key storage dedicated device 14 may be configured to be freely attachable. For example, a memory card 30 may be used as the key storage device 14, and the key storage device 14 may be attached to the card connection device 20. Alternatively, a slot dedicated to the key storage device 14 may be provided in the present content reproduction device, and the key storage device 14 may be attached to this slot. As described above, since the key size is significantly smaller than the encrypted content size, many license keys can be stored in the key storage dedicated device 14. . For this reason, it is possible to prevent a situation in which the key storage dedicated device 14 has to be replaced frequently when the content to be reproduced is changed. Therefore, it is possible to provide a content reproducing apparatus suitable for a stationary type in which content data is reproduced in a house.

Further, in the above embodiment, the license key is prepared for each encrypted content, but the present invention is not limited to this. For example, a license key for decrypting the encrypted content data belonging to the group may be prepared for each group with a plurality of encrypted content groups as one group.

As described above, according to the present invention, it is possible to reproduce a large amount of content without replacing a memory card while protecting the content creator and the like.

Claims

The scope of the claims

1. A content playback device that plays back encrypted content data,

Content storage means for storing the encrypted content, and a key for decrypting the encrypted content data or the content provided for each group of the content. A key storage unit with a calculation function provided separately from the content storage unit; and a reproduction unit for decrypting and reproducing the encrypted content data,

The key storage means with a calculation function,

An authentication unit for authenticating a communication partner; and when the reproducing unit is authenticated as a communication partner by the authentication unit, the reproducing unit encrypts a reproduction target using encryption communication. Sends the key corresponding to the content data

The reproducing means,

Decrypting and playing back the encrypted content to be played back read out from the content storage means using a key transmitted from the key storage means with calculation function using encrypted communication;

Content playback device characterized by the following.

2. The content reproducing apparatus according to claim 1, wherein

The key storage means with a calculation function is configured to be freely attachable to the present content reproducing apparatus.

Content playback device characterized by the following.

3. The content reproducing apparatus according to claim 1, wherein

A connection unit for connecting a storage medium with a calculation function in which a key for decrypting the encrypted content is stored,

The key storage means with a calculation function,

Storing a key transmitted using cryptographic communication from the storage medium with a calculation function connected to the connection means.

Content playback device characterized by the following.

4. The content reproducing apparatus according to claim 3, wherein

The key storage means with a calculation function,

When the storage unit with the calculation function connected to the connection unit is authenticated as a communication partner by the authentication unit, the key held by the storage unit is read out by using the cryptographic communication to perform the calculation. When sending to a storage medium with functions, the transmitted key must be deleted from the stored contents

Content playback device characterized by the following.

5. A content playback device that plays back encrypted content data,

Content reading means for reading the encrypted content data to be reproduced from a portable storage medium storing the encrypted content data;

A key storage unit with a calculation function for storing a key for decrypting the encrypted content data or a content prepared for each group of the data,

Playback means for decrypting and playing back the encrypted content overnight; The key storage means with a calculation function,

An authentication unit that authenticates a communication partner, and when the playback unit is authenticated as a communication partner by the authentication unit, the playback unit encrypts the playback target using encrypted communication. Send the key corresponding to the content overnight,

The reproducing means,

The encrypted content, which is read from the storage medium via the content reading means and is to be played back, is transmitted to the key transmitted by the cryptographic communication from the key storage unit with a calculation function. A content reproducing apparatus, which decodes and reproduces the content by using the content reproducing apparatus.

6. The content reproducing apparatus according to claim 5, wherein

The key storage means with a calculation function is configured to be freely attachable to the content reproducing apparatus.

Content playback device characterized by the following.

7. The content reproducing apparatus according to claim 5, wherein

A connection unit for connecting a storage medium with a calculation function in which a key for decrypting the encrypted content is stored;

The key storage means with a calculation function,

Content playback device characterized by the following.

8. The content reproducing apparatus according to claim 7, wherein

The key storage means with a calculation function, When the storage medium with a calculation function connected to the connection means is authenticated as a communication partner by the authentication means, the key held by the authentication medium is read out using cryptographic communication to execute the calculation. When sending to a storage medium with functions, the transmitted key must be deleted from the stored contents

Content playback device characterized by the following.

9. A content playback device that plays back the encrypted content

Content storage means for storing the encrypted content data, and a key for decrypting the encrypted content data or the content data prepared for each data group; Connection means for connecting a key storage device with a calculation function;

Playback means for decrypting and playing back the encrypted content data; and

The reproducing means,

The encrypted content data to be reproduced, read from the content storage unit, is transmitted from the key storage device with a calculation function connected by the connection unit using cryptographic communication. Decrypting and playing with a key

Content playback device characterized by the following.

10. A content playback device that plays back encrypted content data,

Content reading means for reading the encrypted content data to be reproduced from the portable storage medium storing the encrypted content data; Connecting means for connecting a key storage device with a calculation function for storing a key for decrypting encrypted content data or a content provided for each group of the data; and

Playback means for decrypting and playing back the encrypted content overnight;

The reproducing means,

The encrypted content data to be played back, read from the storage medium via the content reading means, is encrypted by the key storage device with calculation function connected by the connection means. Decrypting and playing with the key transmitted using

Content playback device characterized by the following.

1 1. A key storage device with a calculation function that is used by being attached to a content playback device that decrypts and plays back encrypted content, and that encrypts the content or the data. Key storage means for storing a key for decrypting the content data prepared for each group, authentication means for authenticating a communication partner,

When the content reproducing apparatus is authenticated as a communication partner by the authentication means, a key corresponding to the encrypted content to be reproduced is read out from the key storage means, and encrypted communication is performed. Communication means for transmitting to the content reproduction device.

A key storage device with a calculation function, characterized in that:

1 2. A content playback device that plays back encrypted content

Content storage means for storing the encrypted content data; A decryption key provided separately from the content storage means for storing a key for decrypting the decoded content or a content data prepared for each group of the content. Key storage means for recording, and reproduction means for decrypting and reproducing the encrypted content data,

Key storage means for recording the decryption key,

An authentication unit that authenticates a communication partner, and when the playback unit is authenticated as a communication partner by the authentication unit, the playback unit encrypts the playback target using encrypted communication. Send the key corresponding to the content data,

The reproducing means,

Decrypting the encrypted content data to be played back, read from the content storage means, using a key transmitted using encryption communication from the key storage means for recording the decryption key; To play

A content reproducing device characterized by the following.