JP3621682B2 - Digital broadcasting apparatus and digital broadcasting method, digital broadcasting receiving apparatus, digital broadcasting receiving method, and digital broadcasting receiving system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a digital broadcasting device and a digital broadcasting method, a digital broadcasting receiving device and a digital broadcasting receiving method, and a digital broadcasting receiving system, and more particularly to an improvement in a system for providing a service for providing contents via the Internet in conjunction with the digital broadcasting. .
[0002]
[Prior art]
As is well known, at present, services that provide content to users through Internet communication linked to digital broadcasting tend to be put into practical use. FIG. 6 schematically shows a system for realizing such a digital broadcast-linked Internet content providing service.
[0003]
In FIG. 6, the digital broadcast wave transmitted from the broadcast station 11 is received by the digital broadcast receiver 12, so that a program is provided to the user. This provided program service includes access information [Web server address, URL (Uniform Resource Locator, etc.)] to the linked Web servers 13 and 14.
[0004]
For this reason, the digital broadcast receiver 12 can take in the content linked to the digital broadcast from the Web server 13 by accessing the Web server 13, for example, via the Internet 15 based on the received access information. Become.
[0005]
Such a linked service between digital broadcasting and Internet communication has been developed for the purpose of providing a wider variety of services to users by linking broadcasting content and Web content on the Internet. .
[0006]
This type of linked service has great advantages for broadcasters, such as being able to handle a variety of services by using a standard infrastructure called the Internet, and further reducing operational costs. However, there is a problem that sufficient security for communication data cannot be secured.
[0007]
For example, in the case of a service that involves registering personal information of a user on a Web server, if a malicious person leaks or alters personal information and the user's rights are violated, Reliability is severely impaired and its social impact is immeasurable.
[0008]
In general, a standard protocol called HTTP (Hyper Text Transfer Protocol) is used for data exchange between the digital broadcast receiver and the Web server. As a technique introduced as a solution to the security problem in HTTP communication, there is a technique called TLS (Transport Layer Security) or SSL (Secure Sockets Layer).
[0009]
This TLS implements secure communication using a public key infrastructure (PKI). In other words, this TLS establishes a reliable third party organization called a certification authority (CA) station to authenticate the web server, and the digital broadcasting receiver communicates with the web server authenticated by the CA station. Allow access only. A digital signature is added to the communication data between the digital broadcast receiver and the Web server, and encryption processing is performed to prevent spoofing, falsification, wiretapping, and the like.
[0010]
That is, in FIG. 6, the Web server 13 requests the CA station 16 to issue a certificate (server certificate). Then, the CA station 16 issues a server certificate digitally signed with its own public key to the Web server 13.
[0011]
Similarly, when the Web server 14 requests the CA station 16 to issue a server certificate, the CA station 16 issues a server certificate digitally signed with its own public key to the Web server 14.
[0012]
The CA station 16 publicly discloses its own public key, and the digital broadcast receiver 12 incorporates the public key of the CA station 16 in advance.
[0013]
When the digital broadcast receiver 12 accesses the Web server 13 via the Internet 15, the server certificate is transmitted from the Web server 13. Thereby, the digital broadcast receiver 12 evaluates the digital signature of the received server certificate using the public key of the CA station 16 incorporated in advance.
[0014]
When the reliability of the server certificate has been confirmed in this way, the digital broadcast receiver 12 determines the encryption procedure based on the encryption specification described in the server certificate of the Web server 13, and the Web server 13 Encrypted communication starts with. The same applies when the digital broadcast receiver 12 accesses the Web server 14.
[0015]
As for detailed technical information on HTTP and TLS (SSL), HTTP is published in RFC (Request For Comments) 2616, and TLS is published in RFC2246.
[0016]
FIG. 7 shows details of the broadcast station 11, the digital broadcast receiver 12, the Web server 13, and the CA station 16 described above. First, the server certificate of the Web server 13 and the public key of the CA station 16 held by the digital broadcast receiver 12 used in TLS will be described.
[0017]
The Web server 13 requests the CA station 16 to issue a server certificate. In this case, the Web server 13 generates a key pair of an arbitrary server private key 13a and a public key, and sends it to the CA station 16 including the generated public key in the server certificate issuance request.
[0018]
The CA station 16 that has received the server certificate issuance request creates a server certificate by digitally signing the public key of the Web server 13 with the CA station private key 16a. Issue to the server 13. The issued server certificate is held in the Web server 13 as server certificate data 13b.
[0019]
Further, the CA station 16 publicly discloses a CA station public key corresponding to the CA station private key 16a. The digital broadcast receiver 12 holds the CA station public key as CA station public key data 12a in advance.
[0020]
In the broadcast station 11, the video 11a, the audio 11b, and the data broadcast content 11c are multiplexed by the encoder 11d and transmitted as a digital broadcast wave from the sending device 11e. The server address 11f of the Web server 13 that provides communication content linked to the broadcast program is added to the data broadcast content 11c.
[0021]
In the digital broadcast receiver 12, the digital broadcast wave received by the receiving device 12b is separated into video 12d, audio 12e, and data broadcast content 12f by the decoder 12c. Among these, the video 12d and the audio 12e are output to a playback device (not shown) and presented to the user.
[0022]
The data broadcast content 12f is supplied to the browser 12g. The browser 12g extracts the server address 11f included in the data broadcast content 12f and outputs it to the communication device 12h. The communication device 12 h creates HTTP request data corresponding to TLS based on the input server address 11 f and transmits the HTTP request data to the Internet 15.
[0023]
HTTP request data corresponding to this TLS is received by the communication device 13c of the Web server 13. The communication device 13c takes in the server certificate data 13b and returns it as HTTP data to the communication device 12h of the digital broadcast receiver 12 via the Internet 15.
[0024]
The communication device 12h that has received the HTTP response data evaluates the digital signature added to the input server certificate by using the CA station public key data 12a. If the digital signature of the server certificate is not correct, communication is interrupted assuming that the Web server 13 is an unreliable server.
[0025]
If the digital signature of the server certificate is correct, the communication device 12h determines that the Web server 13 is a reliable server. Then, the communication device 12h transmits the TLS communication parameters necessary for starting the TLS session using the public key described in the server certificate to the communication device 13c of the Web server 13 via the Internet 15.
[0026]
As a result, a handshake for TLS secure communication is performed between the communication device 13c of the Web server 13 and the communication device 12h of the digital broadcast receiver 12.
[0027]
As described above, when the encryption procedure of communication data is determined and a secure HTTP communication path is established, the communication device 13c of the Web server 13 encrypts the communication content generated by the content generation device 13d, and the digital broadcast receiver 12 communication devices 12h.
[0028]
The communication device 12h of the digital broadcast receiver 12 decodes the received communication content. The decrypted communication content is played back by the browser 12g, output as a broadcast-linked content to a playback device (not shown), and presented to the user.
[0029]
When the digital broadcast receiver 12 transmits user information to the Web server 13 based on the communication content, the user data is encrypted by the communication device 12 h of the digital broadcast receiver 12 and stored in the Web server 13. Sent.
[0030]
In TSL communication, the reliability of the server certificate of the Web server 13 is evaluated (server authentication) using the CA station public key of the digital broadcast receiver 12, and data encryption is performed using the public key of the server certificate. Thus, secure communication can be realized. In this case, the precondition is that “the server certificate issued by the CA station 16 is always reliable”.
[0031]
However, there are cases where the reliability of the server certificate itself is lost. As described above, the server public key presented by the server certificate has a paired server private key. The server private key is strictly stored on the Web server side and should not be leaked to the outside.
[0032]
However, in the unlikely event that the server private key is obtained by a malicious person, the person uses the server private key to start the TLS session described above from the digital broadcast receiver side. There is a possibility that the TLS communication parameters encrypted with the server public key transmitted to the Web server side can be decrypted. This significantly reduces the reliability of TLS encrypted data.
[0033]
A server certificate revocation list (CRL) is used as a mechanism for dealing with a situation where a server certificate becomes untrustworthy. The server certificate revocation list is a database of server certificates that can no longer be trusted, and is used to invalidate the validity of the server certificate.
[0034]
With reference to FIG. 7, the server certificate revocation operation based on this server certificate revocation list will be described. That is, when the server certificate issued by the CA station 16 is revoked, the CA station 16 creates server certificate revocation data in which the ID of the server certificate is registered, and performs a digital signature with the CA station private key 16a. A server certificate revocation list is issued and published on the Internet 15.
[0035]
The digital broadcast receiver 12 takes in the server certificate revocation list from the communication device 12h and stores it in the server certificate revocation list holding device 12i.
[0036]
The digital broadcast receiver 12 verifies whether the server certificate transmitted from the Web server 13 is registered in the server certificate revocation list read from the server certificate revocation list holding device 12i during TLS server authentication. To do. If it is registered, the TLS session is interrupted with the reliability of the Web server 13 being rejected, and the TLS session is continued only when it is not registered.
[0037]
By using the server certificate revocation list, it is possible to reliably verify the reliability of the server certificate, the communication content transmitted from the Web server side that is authenticated by the server is safe, and the operation of the communication content When user information is transmitted to the Web server, it is ensured that the user information is handled safely.
[0038]
Details of the TLS server certificate and server certificate revocation list (X.509) are disclosed in RFC 2459.
The basis for determining the reliability of a Web server in TLS is server certification by a CA station. Therefore, the existence of a reliable CA station is essential. The broadcaster selects a reliable CA station, and the manufacturer needs to incorporate the public key and server certificate revocation list of the CA station selected by the broadcaster when the digital broadcast receiver is shipped.
[0039]
The selected CA station updates and publishes the server certificate revocation list in case the server certificate issued by itself is revoked or the private key of the CA station itself expires due to expiration or leakage. The CA public key must be revoked, the new CA public key released, the server certificate revocation list and the CA public key distributed to all digital broadcast receivers, and so forth.
[0040]
The same applies to PCs (Personal Computers) that are the mainstream of current Internet-connected devices. However, in the case of a PC, a user can obtain software from the Internet and install or upgrade the software. It is done normally. For this reason, the update, release, distribution, etc. of the server certificate revocation list and CA public key can be handled in the same manner as the upgrade of the PC software.
[0041]
On the other hand, for example, a broadcast receiving system such as a television receiver does not assume that software (receiver function) is installed or upgraded. In addition, it is considered that many users (viewers) have a sense of resistance to an operation that upgrades software (receiver function).
[0042]
For this reason, as a broadcaster, it is necessary to consider a system that manages and maintains the server certificate revocation list and the CA public key without depending on the user.
[0043]
It is a burden factor on productivity that the manufacturer needs to write the CA public key to the digital broadcast receiver at the time of shipment. Furthermore, it is necessary to consider that the number of registered server certificate revocation lists increases each time a Web server revoked in the course of TLS operation is added, and the data gradually grows. That is, it is necessary to secure a large storage capacity for the server certificate revocation list data on the digital broadcast receiver side, which increases the cost of the digital broadcast receiver.
[0044]
As described above, the maintenance problem regarding the server certificate and the problem of the productivity and cost increase of the digital broadcast receiver are major obstacles in the operation of the broadcast-linked Internet communication service by TLS. .
[0045]
[Problems to be solved by the invention]
In the broadcast-linked Internet communication service by TLS, there are problems of operation of the CA station including maintenance of the server certificate revocation list and the CA station public key, and the server certificate revocation list and CA station public key for the digital broadcast receiver. As a result, the problem of high productivity and high costs arises due to the maintenance, which is a barrier to the introduction and operation of the broadcast-linked Internet communication service by TLS.
[0046]
As a publicly known example, Japanese Patent Laid-Open No. 2001-282748 discloses a centralized management for a plurality of distribution companies by collectively managing content data and encryption keys provided from content holders by a security management organization. A technique for providing and managing content data and an encryption key is disclosed.
[0047]
In JP 2001-325233 A, a registration authority terminal registers a user and transmits a user ID necessary for authentication and an encryption key necessary for decrypting digital data to the user via a network. A technology is disclosed in which a sales company terminal transmits encrypted digital data to a user via a network.
[0048]
However, in any of the known examples, there is no description about solving the problems related to the maintenance and management of the server certificate described above.
[0049]
Therefore, the present invention has been made in consideration of the above circumstances, and is an extremely good digital broadcasting apparatus that can reduce the burden on the maintenance and management of server certificates and can contribute to the introduction and operation of a broadcast-linked Internet communication service. Another object of the present invention is to provide a digital broadcast method, a digital broadcast receiving apparatus, a digital broadcast receiving method, and a digital broadcast receiving system.
[0050]
[Means for Solving the Problems]
The digital broadcasting apparatus according to the present invention is
An issuance means for receiving a certificate issuance request including a server public key from the server, digitally signing the server public key with its own broadcasting station private key, creating a server certificate, and outputting to the server;
Transmission means for transmitting program data, access information for accessing a server that provides content linked to the program data via the Internet, and a broadcasting station public key for evaluating the digital signature of the server certificate; Is provided.
[0051]
The digital broadcasting method according to the present invention is
An issuance step of receiving a certificate issuance request including a server public key from the server, creating a server certificate by digitally signing the server public key with its own broadcasting station private key, and outputting to the server;
A transmission step of transmitting program data, access information for accessing a server providing content linked to the program data via the Internet, and a broadcasting station public key for evaluating a digital signature of a server certificate; It is made to have.
[0052]
Furthermore, the digital broadcast receiving apparatus according to the present invention provides:
Receiving means for receiving program data, access information for accessing a server providing content linked to the program data via the Internet, and a broadcasting station public key;
Based on the access information received by the receiving means, a server certificate digitally signed with a broadcast station private key is obtained from a server accessed via the Internet, and the digital signature of the server certificate is broadcast station public key And an evaluation means for evaluating using the above.
[0053]
In addition, the digital broadcast receiving method according to the present invention includes:
A receiving step of receiving program data, access information for accessing a server that provides content linked to the program data via the Internet, and a broadcast station public key;
Based on the access information received in this receiving step, a server certificate digitally signed with a broadcast station private key is obtained from a server accessed via the Internet, and the digital signature of the server certificate is broadcast station public key And an evaluation step of evaluating using the method.
[0054]
Furthermore, a digital broadcast receiving system according to the present invention provides a broadcast station that broadcasts program data, a digital broadcast receiver that receives program data broadcast from the broadcast station, and content linked to the program data, A broadcast receiver with a server accessible via the Internet,
A server issues a certificate issuance request including a server public key to the broadcasting station, causes the broadcasting station to create a server certificate by digitally signing the server public key with its own broadcasting station private key, and Issuing means for outputting;
Transmission means for transmitting together with program data from the broadcast station, access information for accessing the server via the Internet, and a broadcast station public key for evaluating the digital signature of the server certificate;
The digital broadcast receiver receives the access information and broadcasting station public key transmitted by the transmission means, allows the server to be accessed via the Internet based on the access information, and obtains a server certificate from the accessed server, Evaluation means for evaluating the digital signature of the server certificate by using the public key of the broadcasting station is provided.
[0055]
According to the configuration, method, and system as described above, it is possible to eliminate the need for the operation of the CA station and the need to use the server certificate revocation list as in the prior art. It is possible to reduce the burden associated with document maintenance and management, and to effectively promote the introduction and operation of digital broadcasting-linked Internet communication services.
[0056]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 schematically shows a system for realizing a digital broadcast-linked Internet content providing service described in this embodiment.
[0057]
In FIG. 1, a digital broadcast wave transmitted from a broadcast station 17 is received by a digital broadcast receiver 18 so that a program is provided to the user. The provided program service includes access information (Web server address, URL, etc.) to the linked Web servers 19 and 20.
[0058]
For this reason, the digital broadcast receiver 18 can capture content linked to the digital broadcast from the Web server 19 by accessing, for example, the Web server 19 via the Internet 21 based on the received access information. Become.
[0059]
Here, when the Web server 19 requests the broadcast station 17 to issue a certificate (server certificate), the broadcast station 17 issues a server certificate digitally signed with its own public key to the Web server 19. To do.
[0060]
Similarly, when the Web server 20 requests the broadcast station 17 to issue a certificate, the broadcast station 17 issues to the Web server 20 a server certificate digitally signed with its own public key. Therefore, it is not necessary to install the CA station 16 as in the prior art.
[0061]
First, the broadcasting station 17 sends out the public key of the broadcasting station 17 together with program data linked to digital broadcasting / Internet communication. Then, the digital broadcast receiver 18 receives digital broadcast / Internet communication linked program data and the public key of the broadcast station 17.
[0062]
The digital broadcast receiver 18 accesses the Web server 19 linked to the program data via the Internet 21. Then, the Web server 19 transmits a server certificate to the digital broadcast receiver 18.
[0063]
The digital broadcast receiver 18 evaluates the digital signature of the server certificate using the public key of the broadcast station 17, and when the reliability of the server certificate is confirmed, starts secure HTTP communication with the Web server 19 and TLS. To do. The same applies when the digital broadcast receiver 18 accesses the Web server 20.
[0064]
FIG. 2 shows the details of the broadcast station 17, the digital broadcast receiver 18, and the Web server 19 described above. That is, the Web server 19 requests the broadcast station 17 to issue a server certificate. In this case, the Web server 19 generates a key pair of the server private key 19a and the server public key, and transmits the key pair including the public key in the server certificate issuance request to the broadcasting station 17.
[0065]
Upon receiving the server certificate issuance request, the broadcasting station 17 creates a server certificate by digitally signing the public key of the Web server 19 using the broadcasting station private key 17a, and the server certificate is sent to the Web Issue to server 19. The Web server 19 holds the issued server certificate as server certificate data 19b.
[0066]
In the broadcast station 17, the video 17b, the audio 17c, and the data broadcast content 17d are multiplexed by the encoder 17e and transmitted as a digital broadcast wave from the transmission device 17f.
[0067]
The data broadcast content 17d is added with a server address 17g of a Web server 19 that provides communication content linked to a broadcast program, and a broadcast station public key 17h.
[0068]
In the receiver 18, the digital broadcast wave received by the receiver 18a is separated into a video 18c, audio 18d, and data broadcast content 18e by the decoder 18b. Among these, the video 18c and the audio 18d are output to a playback device (not shown) and presented to the user. In addition, the broadcast station public key 17h is separated from the data broadcast content 18e and held as broadcast station public key holding data 18f.
[0069]
On the other hand, the data broadcast content 18e is supplied to the browser 18g. The browser 18g extracts the server address 17g included in the input data broadcast content 18e, and outputs it to the communication device 18h as Web server access data. The communication device 18 h creates HTTP request data corresponding to TLS based on the input Web server access data and transmits the HTTP request data to the Internet 21.
[0070]
The HTTP request data corresponding to the TLS is received by the communication device 19c of the Web server 19 via the Internet 21. The communication device 19c takes in the server certificate data 19b and returns it as HTTP data to the communication device 18h of the digital broadcast receiver 18 via the Internet 21.
[0071]
The communication device 18h of the digital broadcast receiver 18 that has received the HTTP response data reads the broadcast station public key 17h from the held broadcast station public key holding data 18f, and transmits it from the Web server 19 using the broadcast station public key 17h. Evaluate the digital signature attached to the signed server certificate.
[0072]
If the digital signature of the server certificate is not correct, the communication device 18h determines that the Web server 19 is an unreliable server and interrupts communication.
[0073]
If the digital signature of the server certificate is correct, the communication device 18h determines that the Web server 19 is a reliable server, and starts TLS communication using the public key described in the server certificate.
[0074]
Then, the communication device 19c of the Web server 19 encrypts the communication content generated by the content generation device 19d and transmits it to the communication device 18h of the digital broadcast receiver 18.
[0075]
The communication device 18h of the digital broadcast receiver 18 decodes the received communication content. The decrypted communication content is played back by the browser 18g, is output as a broadcast-linked content to a playback device (not shown), and is presented to the user.
[0076]
When the digital broadcast receiver 18 transmits user information to the Web server 19 based on the communication content, the user data is encrypted by the communication device 18 h of the digital broadcast receiver 18, and the Web server 19. Sent to.
[0077]
In the broadcasting station 17, it is possible to easily change the broadcasting station public key 17h held in the digital broadcasting receiver 18 via the digital broadcasting wave. For this reason, the broadcasting station 17 changes the broadcasting station key pair 17i composed of the broadcasting station public key 17h and the broadcasting station secret key 17a for each program, and uses the changed broadcasting station public key 17h to the Web server 19. By issuing a server certificate, the validity period of the server certificate can be shortened.
[0078]
When the reliability of the server certificate is lost, the Web server 19 can suppress the spread of damage as much as possible by stopping the provision of the broadcast-linked service in which the server certificate is valid.
[0079]
Therefore, it is not necessary to use the server certificate revocation list described in the conventional system. Moreover, unlike the CA station public key of the conventional system, it is very easy to change the broadcast station public key, so the convenience of the broadcast station in the operation of the broadcast-linked communication content service is improved.
[0080]
Further, it is not necessary to incorporate a server certificate revocation list in advance in the digital broadcast receiver. In addition, it is not necessary to secure a storage area for the server certificate revocation list in the digital broadcast receiver, resulting in a great merit in the productivity and cost of the digital broadcast receiver.
[0081]
According to the above-described embodiment, since the data certifying the reliability of the broadcast-linked Web server included in the broadcast data is transmitted, the broadcast-linked content Web server can be operated without operating the CA station in the conventional system. Reliability can be ensured.
[0082]
3 and 4 show another embodiment of the present invention. 3 and 4, the same parts as those in FIG. 2 are denoted by the same reference numerals.
[0083]
That is, the Web server 19 sends the content Ct linked to the broadcast to the broadcast station 17. The broadcast station 17 generates a content ID (Id) that is identification information for the content Ct by the content ID generation device 17j, adds the content Ct and the content ID (Id) by the adder 17k, and obtains an added output Ct + Id.
[0084]
This added output Ct + Id is subjected to irreversible function conversion processing by the digest function processing device 17l and converted into a digest value M (Ct + Id), and then is added to the middle of the key pair generated by the key generation device 17n by the encryption device 17m. And the digital signature S = E [M (Ct + Id)].
[0085]
The digital signature S of the content Ct and the content ID (Id) is output to the synthesizing device 19e of the Web server 19, and synthesized with the content Ct to become Ct + S, and is supplied to the communication device 19c.
[0086]
In the broadcast station 17, the video 17b, the audio 17c, and the data broadcast content 17d are multiplexed by the encoder 17e and transmitted as a digital broadcast wave from the transmission device 17f.
[0087]
The data broadcast content 17d includes the server address 17g of the Web server 19 that provides communication content linked to the broadcast program, the public key Pk in the key pair generated by the key generation device 17n, and the content ID (Id). Added.
[0088]
In the digital broadcast receiver 18, the digital broadcast wave received by the receiving device 18a is separated into video 18c, audio 18d, and data broadcast content 18e by the decoder 18b. Among these, the video 18c and the audio 18d are output to a playback device (not shown) and presented to the user.
[0089]
Further, the server address, the public key Pk, and the content ID (Id) are separated from the data broadcast content 18e, and are held in the server address holding device 18i, the public key holding device 18j, and the content ID holding device 18k, respectively.
[0090]
The server address held in the server address holding device 18i is output to the communication device 18h as access data to the linked Web server 19. The communication device 18h sends the input access data to the Internet 21 as HTTP request data corresponding to TLS.
[0091]
This HTTP request data is received by the communication device 19c of the linked Web server 19. The communication device 19c of the Web server 19 returns the digitally signed content data Ct + S as an HTTP response to the communication device 18h of the digital broadcast receiver 18 via the Internet 21.
[0092]
The HTTP response data received by the communication device 18h of the digital broadcast receiver 18 is separated into content data Ct and digital signature data S by the separation device 18g1 constituting the browser 18g.
[0093]
The digital signature data S is input to the decryptor 18g2, decrypted by the public key data Pk stored in the public key storage device 18j, and input to one input terminal of the comparison device 18g3.
[0094]
On the other hand, the content data Ct is supplied to the adder 18g4 and the content processing device 18g5. The content data Ct is added to the content ID (Id) taken out from the content ID holding device 18k by the adder 18g4 to become Ct + Id.
[0095]
This addition output Ct + Id is digest-processed by the digest function processing device 18g6 to become a message digest M (Ct + Id), and is input to the other input terminal of the comparison device 18g3.
[0096]
The decrypted data of the digital signature data S and the message digest M (Ct + Id) are compared by the comparison device 18g3, and the comparison result is output to the control device 18g7.
[0097]
When the decrypted data of the digital signature data S is equal to the message digest M (Ct + Id), the control device 18g7 permits the content processing procedure 18g5 to process the content Ct and presents it to the user.
[0098]
Further, when the decrypted data of the digital signature data S and the message digest M (Ct + Id) are different, the control device 18g7 prohibits the content processing procedure 18g5 from processing the content Ct and disables the presentation to the user. .
[0099]
As described above, according to the embodiment shown in FIGS. 3 and 4, the digital signature data S added to the content transmitted by the linked Web server is used as the public key Pk transmitted as broadcast data. By verifying with the content ID (Id), the reliability and safety of the content can be evaluated.
[0100]
The broadcast station 17 can switch the content ID in units of content, and can sufficiently ensure the reliability of the digital signature of the content.
[0101]
FIG. 5A shows a modification of the content ID generation device 17j of the broadcast station 17. That is, a plurality (three in the illustrated case) of content ID generators 17j1, 17j2, 17j3 are provided, and the content IDs generated by the content ID generators 17j1, 17j2, 17j3 are multiplexed by the ID multiplexer 17j4. I am trying to send it out.
[0102]
In this case, in the content ID holding device 18k of the digital broadcast receiver 18, as shown in FIG. 5 (b), the plurality of multiplexed content IDs are separated by the ID separation device 18k1, and each separated content ID is separated. By holding the holding devices 18k2, 18k3, and 18k4, it is possible to efficiently authenticate a plurality of content IDs.
[0103]
Here, in each of the above-described embodiments, the data broadcast content including the access information to the Web server that provides the communication content linked to the broadcast program is broadcast using the practical channel of the broadcast station. For example, if a broadcasting station has a dedicated download channel, it may be broadcast using the download channel.
[0104]
According to each of the above-described embodiments, first, it is not necessary to operate the CA station. Also, unlike the CA station public key, it is very easy to change the broadcast station public key, so that the operation cost of the broadcast station in the operation of the broadcast-linked communication content service can be reduced. Furthermore, it is not necessary to embed a server certificate revocation list in advance in the digital broadcast receiver or to secure a storage area for the server certificate revocation list, thereby improving the productivity of the digital broadcast receiver and reducing the cost. Can do.
[0105]
The present invention is not limited to the above-described embodiments, and can be variously modified and implemented without departing from the scope of the invention.
[0106]
【The invention's effect】
As described above in detail, according to the present invention, a very good digital broadcasting apparatus and digital broadcasting method that can reduce the burden related to server certificate maintenance management and contribute to the promotion and introduction of broadcast-linked Internet communication services. A digital broadcast receiving apparatus, a digital broadcast receiving method, and a digital broadcast receiving system can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram schematically showing a system for realizing a digital broadcast-linked Internet content providing service according to an embodiment of the present invention.
FIG. 2 is a block configuration diagram shown for explaining details of a broadcast station, a digital broadcast receiver, and a Web server in the embodiment.
FIG. 3, showing another embodiment of the present invention, is a block diagram showing the details of a broadcasting station and a Web server.
FIG. 4 is a block diagram showing the details of a digital broadcast receiver according to another embodiment.
FIG. 5 is a block configuration diagram shown for explaining a modification of the content ID generation device and the content ID holding device according to the other embodiment.
FIG. 6 is a block diagram schematically showing a system that realizes a digital broadcasting-linked Internet content providing service that is currently considered.
FIG. 7 is a block diagram showing details of a broadcasting station, a digital broadcasting receiver, a Web server, and a CA station in the system.
[Explanation of symbols]
11 ... Broadcasting station
12 ... Digital broadcast receiver,
13: Web server,
14 ... Web server,
15 ... Internet,
16 ... CA station,
17 ... Broadcasting station,
18 ... Digital broadcast receiver,
19 ... Web server,
20 ... Web server,
21 ... Internet.

Claims (18)

An issuance means for receiving a certificate issuance request including a server public key from a server, creating a server certificate by digitally signing the server public key with its own broadcasting station private key, and outputting the server certificate to the server;
Transmission means for transmitting program data, access information for accessing a server providing content linked to the program data via the Internet, and a broadcasting station public key for evaluating a digital signature of the server certificate A digital broadcasting apparatus comprising: Adding means for adding identification information to the content generated by the server, converting means for performing irreversible function conversion processing on the output of the adding means, and encrypting by using the private key of the broadcasting station for the output of the converting means Issuing means comprising an output means for generating a digital signature by performing a digitization process and outputting the digital signature;
Program data, access information for accessing a server that provides content linked to the program data via the Internet, identification information added to the content, and a digital signature of the content to which the identification information is added A digital broadcast apparatus comprising: a transmission means for transmitting a broadcast station public key for evaluation. The digital broadcasting apparatus according to claim 2, wherein the issuing means multiplexes and adds a plurality of identification information to the content generated by the server. An issuance step of receiving a certificate issuance request including a server public key from a server, creating a server certificate by digitally signing the server public key with its own broadcasting station private key, and outputting to the server;
A transmission step of transmitting program data, access information for accessing a server providing content linked to the program data via the Internet, and a broadcasting station public key for evaluating the digital signature of the server certificate And a digital broadcasting method. An addition step of adding identification information to the content generated by the server, a conversion step of performing an irreversible function conversion process on the output of the addition step, and an encryption using the broadcasting station secret key for the output of the conversion step A digital signature is created by performing a digitization process, and an output process comprising an output process for outputting to the server;
Program data, access information for accessing a server that provides content linked to the program data via the Internet, identification information added to the content, and a digital signature of the content to which the identification information is added A digital broadcasting method comprising: a transmitting means for transmitting a broadcasting station public key for evaluation. 6. The digital broadcasting method according to claim 5, wherein the issuing step includes a step of multiplexing and adding a plurality of pieces of identification information to the content generated by the server. Receiving means for receiving program data, access information for accessing a server providing content linked to the program data via the Internet, and a broadcasting station public key;
Based on the access information received by the receiving means, a server certificate digitally signed with a broadcasting station private key is obtained from a server accessed via the Internet, and the digital signature of the server certificate is obtained from the broadcasting station A digital broadcast receiving apparatus, comprising: evaluation means for evaluating using a public key. Receiving means for receiving program data, access information for accessing a server providing content linked to the program data via the Internet, identification information added to the content, and a broadcast station public key;
Based on the access information received by the receiving means, the content that has been added with the digital signature by the broadcasting station private key is acquired from the server accessed via the Internet and is added to the content. A digital broadcast receiving apparatus comprising: evaluation means for evaluating the digital signature using the identification information and the broadcast station public key. The evaluation means includes
Decrypting means for decrypting the digital signature obtained via the Internet using the broadcasting station public key received by the receiving means;
Adding means for adding the content acquired via the Internet and the identification information received by the receiving means;
Conversion means for performing irreversible function conversion processing on the output of the addition means;
9. The digital broadcast receiving apparatus according to claim 8, further comprising a comparing means for comparing the output of the converting means and the output of the decoding means. 9. The digital broadcast receiving apparatus according to claim 8, wherein the evaluation unit separates and holds a plurality of pieces of identification information multiplexed on content acquired via the Internet. A receiving step of receiving program data, access information for accessing a server that provides content linked to the program data via the Internet, and a broadcast station public key;
Based on the access information received in the receiving step, a server certificate digitally signed with a broadcasting station private key is obtained from a server accessed via the Internet, and the digital signature of the server certificate is obtained from the broadcasting station A digital broadcast receiving method comprising: an evaluation step of evaluating using a public key. A receiving step for receiving program data, access information for accessing a server providing content linked to the program data via the Internet, identification information added to the content, and a broadcast station public key;
Based on the access information received in this receiving step, the content that has been added with the digital signature by the broadcast station private key is acquired from the server accessed via the Internet, including the identification information, and added to the content. A digital broadcast receiving method comprising: an evaluation step of evaluating the digital signature using the identification information and the broadcast station public key. The evaluation step includes
Decrypting the digital signature obtained via the Internet using the broadcasting station public key received in the receiving step;
An adding step of adding the content acquired via the Internet and the identification information received in the receiving step;
A conversion step of performing an irreversible function conversion process on the output of the addition step;
13. The digital broadcast receiving method according to claim 12, further comprising a comparison step of comparing the output of the conversion step and the output of the decoding step. 13. The digital broadcast receiving method according to claim 12, wherein the evaluation step includes a step of separately holding a plurality of pieces of identification information multiplexed on the content acquired via the Internet. A broadcast station that broadcasts program data, a digital broadcast receiver that receives program data broadcast from this broadcast station, and contents linked to the program data are provided, and the digital broadcast receiver is accessible via the Internet Server and
The server issues a certificate issuance request including a server public key to the broadcast station, and causes the broadcast station to create a server certificate by digitally signing the server public key with its own broadcast station private key. Issuing means for causing the server to output;
Transmission means for transmitting access information for accessing the server via the Internet together with the program data from the broadcast station and a broadcast station public key for evaluating the digital signature of the server certificate;
The digital broadcast receiver is caused to receive the access information and the broadcast station public key transmitted by the transmission means, and the server is accessed via the Internet based on the access information, and the accessed server from the accessed server A digital broadcast receiving system comprising: an evaluation unit that obtains a server certificate and evaluates a digital signature of the server certificate using the broadcast station public key. A broadcast station that broadcasts program data, a digital broadcast receiver that receives program data broadcast from this broadcast station, and contents linked to the program data are provided, and the digital broadcast receiver is accessible via the Internet Server and
The broadcast station is allowed to add identification information to the content provided from the server, perform an irreversible function conversion process on the content to which the identification information is added, and output the function conversion process output to its own broadcast station private key. Issuing means for carrying out encryption processing using the to create a digital signature and outputting to the server;
Combining means for causing the server to add a digital signature output from the communication means to the content provided by the server;
Transmission means for transmitting access information for accessing the server via the Internet, identification information added to the content, and a broadcast station public key together with the program data from the broadcast station,
The digital broadcast receiver is made to receive the access information, the identification information and the broadcast station public key transmitted by the transmission means, and the server is accessed via the Internet based on the access information. Evaluation means for acquiring the digital signature added content from a server and evaluating the digital signature added to the content using the identification information and the broadcast station public key. Digital broadcast receiving system. The evaluation means includes
Decryption means for decrypting the digital signature obtained via the Internet using the received broadcast station public key;
Adding means for adding the content acquired via the Internet and the received identification information;
Conversion means for performing irreversible function conversion processing on the output of the addition means;
17. The digital broadcast receiving system according to claim 16, further comprising comparison means for comparing the output of the conversion means and the output of the decoding means. The issuing means multiplexes and adds a plurality of identification information to the content provided by the server,
17. The digital broadcast receiving system according to claim 16, wherein the evaluation unit separates and holds a plurality of pieces of identification information multiplexed on content acquired via the Internet.

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