JP5145703B2 - Distribution system and distribution method - Google Patents

Description

The present invention relates to a plurality of terminals, to a delivery system and a delivery how to distribute the cryptographic key.

  In the operation of the video distribution system, security measures such as copyright protection and unauthorized viewing prevention for the video content are required. Patent Document 1 discloses an encryption method in which video content data is encrypted using an encryption key that is changed in units of seconds and multicast distribution is performed. In a video distribution system, an encryption key distribution server that distributes an encryption key to a large number of users is usually provided separately from a video distribution server that distributes video distribution contents. Furthermore, in a large-scale video distribution system in which the number of viewing users reaches 100,000 units, a plurality of encryption key distribution servers are provided, and the load on each encryption key distribution server is distributed.

By the way, in a video distribution system including a plurality of encryption key distribution servers, there is a problem that a mechanism for preventing double viewing is complicated. Double viewing refers to a user who has only one viewing license making a viewing request to each of a plurality of encryption key distribution servers, and receiving video keys from each of them to reproduce video content on a plurality of viewing terminals. In order to prevent such double viewing, the encryption key distribution server that distributes the encryption key to each user at that time is always grasped so that no other encryption key distribution server distributes the encryption key to the user. It is necessary to provide a device such as a viewing control server for performing control.
JP 2003-174441 A

  However, providing a viewing control server that performs such complex control is only redundant in terms of data management in that user information regarding each user needs to be shared between the viewing control server and a plurality of encryption key distribution servers. Therefore, it is necessary to transfer the user information between the viewing control server and the encryption key distribution server every time the user information is updated, and the load on the viewing control server and the encryption key distribution server is greatly increased. There is a problem that the performance is reduced.

  An object of the present invention is to provide a video distribution system that realizes double viewing prevention and does not significantly increase the load on a server such as a viewing control server or an encryption key distribution server.

Delivery system that by the present invention, the plurality of terminals contents encrypted is made are delivered, a plurality of servers, each of which distributes the encryption key corresponding to the encryption of delivery stop processing unit and the encryption key a first encryption key distribution server and the second encryption key distribution server including delivery system and a delivery stop means respectively, first generated based on the viewing request of content from one of said plurality of terminals An encryption key distribution server allocating unit that receives one request signal and allocates the first encryption key distribution server to the one terminal as an allocated encryption key distribution server, and the distribution stop processing unit included in the first server includes : , wherein one distributes the encryption keys used by the terminal, and sends a distribution stop request signal designating said one terminal to the second encryption key distribution server, included in the second encryption key distribution server Previous Encryption key distribution stop means receives the distribution stop request signal, characterized in that you stop the delivery of encryption keys used in the one terminal.
The distribution method according to the present invention is a server that distributes an encryption key corresponding to the encryption to a plurality of terminals to which the encrypted content is distributed, a distribution stop processing means and an encryption key distribution stop means A distribution method in a distribution system including a first encryption key distribution server and a second encryption key distribution server, each including encryption key distribution server allocation means in the system, wherein the encryption key distribution server allocation The means receives a first request signal generated based on a content viewing request from one of the plurality of terminals, and sets the first encryption key distribution server as the assigned encryption key distribution server to the one terminal. An encryption key distribution server allocating step, wherein the distribution stop processing means included in the first encryption key distribution server is a cipher used in the one terminal. And a distribution stop processing step of transmitting a distribution stop request signal specifying the one terminal to the second encryption key distribution server, the encryption key distribution stop means included in the second encryption key distribution server Includes an encryption key distribution stop step of receiving the distribution stop request signal and stopping distribution of an encryption key used in the one terminal.

According to the onset bright, it is possible to realize a dual view prevention has never allowed to increase greatly server load, such as viewing control server or encryption key distribution server.

  Embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows an embodiment of the present invention, and shows the overall configuration including a video distribution system. The video distribution system 100 is a system that multicasts video content such as movies to each of the plurality of viewing terminals 10a to 10c via a video distribution network 90 such as the Internet. Each of the viewing terminals 10a to 10c is a device used by a user, and is a video reproduction device such as a television connected to an STB (Set Top Box) or the like. In this figure, only three viewing terminals 10a to 10c are shown for ease of explanation, but the present invention assumes a viewing terminal with a scale of 100,000 more.

  In this embodiment, the video content is encrypted and distributed by the video distribution server 60 using an encryption key called TEK (Traffic Encryption Key). This encryption key called TEK is encrypted by each of the encryption key distribution servers 50a to 50c using an encryption key called KEK (Key Encryption Key) and distributed to each of the viewing terminals 10a to 10c.

  The video distribution system 100 includes at least one viewing control server 30, at least one load distribution server 40, a plurality of encryption key distribution servers 50 a to 50 c, and at least one video distribution server 60. In the figure, only three encryption key distribution servers 50a to 50c are shown for ease of explanation, but the present invention may include four or more encryption key distribution servers.

The viewing control server 30 is a server that authenticates the user in response to a viewing request from the user and supplies a cash-in request message for requesting creation of user information related to the user to the load distribution server 40. The viewing control server 30 is a server that performs normal user authentication and transfers the cashin request to the encryption key distribution server, and a configuration used in a conventional existing system can be used as it is. The HTTP protocol that enables normal Web distribution via the video distribution network 90 is used for data communication between each of the viewing terminals 10 a to 10 c and the viewing control server 30. In response to the cash-in request supplied from the network, a load balance (Load Balance) based on the expected load amount for each of the viewing terminals 10a to 10c, for example, traffic is appropriately sent to the encryption key distribution servers 50a to 50c. One of the encryption key distribution servers 50a to 50c is allocated to the viewing terminal so as to be distributed over the server, and the cash-in request is transferred to the allocated allocation encryption key distribution server. In this form, the load distribution server 40 is provided separately from the viewing control server 30, and the load distribution function can be easily provided to an existing system.

  Each of the plurality of encryption key distribution servers 50a to 50c responds to the transferred cashin request with an encryption key for decrypting video content toward the viewing terminal of the user corresponding to the request, for example, the viewing terminal 10a. Is a server that distributes via the video distribution network 90 using the TCP protocol. The video distribution server 60 is a server that distributes video content to a plurality of viewing terminals 10a to 10c via the video distribution network 90 using the RTP protocol for IP broadcast distribution by the multicast method.

  FIG. 2 shows the configuration of the encryption key distribution server shown in FIG. Here, one encryption key distribution server 50 having a common configuration is shown as a representative of each of the encryption key distribution servers 50a to 50c shown in FIG. The encryption key distribution server 50 includes a communication control unit 51, an encryption key generation unit 52, an encryption key distribution unit 53, a user information management unit 54, an encryption key database 58, and a user information database 59.

  The communication control unit 51 has functions of realizing data communication via the local network 20 and realizing data communication including encryption key distribution via the video distribution network 90. The TCP protocol is used for message communication such as a cashin request performed between the load distribution server 40 and the key distribution servers 50a to 50c and encryption key distribution for the viewing terminals 10a to 10b.

  The encryption key generation unit 52 has a function of sequentially generating and updating an encryption key corresponding to each of video contents for each of a plurality of channels as time passes and storing the encryption key in the encryption key database 58. As an encryption key generation algorithm, for example, a technique such as DES (Data Encryption Standard) is used. The encryption key distribution unit 53 has a function of distributing the encryption key stored in the encryption key database 58 to the viewing terminal of the user assigned to the encryption key via the communication control unit 51. The encryption key distribution timing is, for example, every 30 to 1 hour.

  The user information management unit 54 has a function of generating user information in response to a cash-in request supplied via the communication control unit 51 and storing and storing the user information in the user information database 59. The user information management unit 54 also has a function of deleting user information corresponding to a user designated for deletion from the user information database 59 in response to a user information deletion request which is a distribution stop request from another encryption key distribution server. Prepare. In this case, the user information to be deleted is user information generated and stored in response to a previous cash-in request. Therefore, if there is no user information corresponding to the user designated for deletion, the deletion is not performed.

  FIG. 3 shows a configuration example of the user information database shown in FIG. Here, the user information database 59 includes user information pieces 591 to 59n (n is a positive number) for each of a plurality of users who receive video content distribution. Each of the user information pieces 591 to 59n includes a user ID, viewable channel information, a channel address, a viewable expiration date, a ticket, a viewing channel, and a KEK (Key Encryption Key).

  The user ID is an ID for identifying the user. A plurality of viewable channel information are multicast videos that are permitted to be viewed and are held in plural. The channel address is a multicast distribution destination address. The viewable time limit is the date and time when viewing is possible. The ticket is a ticket for communication between the viewing terminal and the key distribution server, and is updated for each viewing request. The viewing channel is the channel address that the viewing terminal is currently viewing. KEK is an encryption key used when distributing an encryption key (TEK) for decrypting multicast video from the key distribution server to the viewing terminal.

  FIG. 4 shows a configuration example of the encryption key database shown in FIG. Here, the encryption key database 58 includes a plurality of encryption key arrays 581 to 58m (m is a positive number). Each of the encryption key arrays 581 to 58m stores, for example, 4 encryption keys (TEK) 1 to 4 corresponding to the channel numbers, and is updated every 30 minutes to 1 hour, for example. Each of the encryption keys 1 to 4 is generated by an encryption generation algorithm such as DES. If one encryption key distribution server distributes four encryption keys having a key length of 32 bytes to 100,000 users, the data of the encryption key extending to 32 bytes × 4 × 100,000 to 30 minutes to 1 It is necessary to deliver every hour.

  FIG. 5 shows a processing procedure in the video distribution system according to the present invention. Here, the processing procedure is such that the viewing terminal 10, the viewing control server 30, the load distribution server 40, the three encryption key distribution servers 50a to 50c, and the video distribution server 60 operate in cooperation. Executed.

  First, the viewing terminal 10 transmits a user ID and password to the viewing control server 30 to make a viewing request (step S1). In response to the viewing request, the viewing control server 30 performs user authentication (step S2). Next, in the case of authentication OK, the viewing control server 30 makes a cash-in request including the user ID related to the user, viewable channel information, and the viewable time limit to the load distribution server 40 (step S3). . In response to the cashin request, the load distribution server 40 assigns one of the three encryption key distribution servers 50a to 50c, here, as an example, the encryption key distribution server 50a (step S4). Next, the cash-in request is transferred to the assigned encryption key distribution server 50a (step S5).

  In response to the transferred cash-in request, the encryption key distribution server 50a generates user information based on the cash-in request, stores it in the user information database, and holds it (step S6). If user information has already been stored in the user information database for the user, the user information is replaced with newly generated user information. That is, as for the cash-in request, the subsequent cash-in request becomes valid. The user information is generated in association with the user ID, and includes information such as a channel address, a multicast distribution destination address, a ticket, a viewing channel, and KEK (Key Encryption Key).

  Next, the encryption key distribution server 50a transmits a cashin response including the generated ticket to the viewing control server 30 (step S7). The viewing control server 30 returns a viewing response including the received ticket and the address of the encryption key distribution server 50a to the viewing terminal 10 (step S8). Since the cache-in response and the viewing response are performed prior to processing related to user information deletion described later, there is no delay in the response time for the viewing terminal 10.

  In response to reception of the transmitted ticket and the address of the encryption key distribution server 50a, the viewing terminal 10 presents the ticket to the address of the encryption key distribution server 50a and requests an encryption key for video content decryption. Can do. The encryption key distribution server 50a starts distributing an encryption key (TEK) for decrypting the video content (step S13).

  On the other hand, the encryption key distribution server 50a transmits a user information deletion request regarding the user to the encryption key distribution server 50b (step S9). In response to the user information deletion request, the encryption key distribution server 50b deletes the user information of the user ID from its own user information database (step S10). Also, the encryption key distribution server 50a transmits a user information deletion request including a user ID corresponding to the user to the encryption key distribution server 50c (step S11). In response to the user information deletion request, the encryption key distribution server 50c deletes the user information of the user ID from its own user information database (step S12). As a result, even if the viewing terminal 10 requests encryption key distribution to the encryption key distribution server 50b or 50c other than the assigned encryption key distribution server 50a, there is no user information of the user ID (non-retention) Therefore, key distribution is not stopped and double distribution is not performed. Further, since the user information deletion request is made after a cash-in response to the viewing terminal, there is no response delay to the viewing terminal.

  The viewing terminal 10 receives the video content that is multicast from the video distribution server 60, and reproduces it while decrypting it using the encryption key distributed from the encryption key distribution server 50a (step S14).

  FIG. 6 shows an analysis result of an increase in load caused by a user information deletion request between encryption key distribution servers. When the present invention is implemented, there is an advantage that only the encryption key distribution server assigned to the user needs to hold the user information to be generated in response to the viewing request from the user. The disadvantage is the increase in communication of information deletion requests. Therefore, hereinafter, the load increase rate of the encryption key distribution server is estimated.

  A simulation for estimating the load increase rate is performed by installing software that simulates the operation of the encryption key distribution server in a configuration in which the server group such as each encryption key distribution server is a workstation and the viewing terminal is a personal computer. It was. As a simulation condition, it is assumed that one user views the viewing contents of one channel for 30 minutes. The number of encryption key distribution servers is three.

  In the simulation result shown in FIG. 6, when the time required for all the requests is totaled, a result of total time: 0.011 + 0.519 + 0.012 + 0.011 + 0.006 = 0.559 [sec] is obtained.

  On the other hand, when the present invention is implemented, one encryption key distribution server in response to a cache-in request needs to make a user information deletion request to the other two encryption key distribution servers. Since the time required for the user information deletion request is almost the same as the viewing end request in terms of processing, the time required for the viewing end request is extra for the other two encryption key distribution servers. That is, it is estimated that the total time in the present invention is 0.006 × (3-1) + 0.011 + 0.519 + 0.012 + 0.011 + 0.006 = 0.571 [sec]. Therefore, an analysis result of a load ratio of the conventional and the present invention: 0.571 / 0.559 × 100 = 102 [%] is obtained.

  In the above analysis results, the load increase rate when the present invention is implemented is 2%. This result is a result of a simple shortest viewing sequence, and in consideration of the fact that channel setting and TEK request are actually repeated, and that the user information deletion request is made only at the time of a cache-in request, the load increase rate is It is estimated to be smaller than 2%.

  In the above embodiment, a mode is shown in which only the encryption key distribution server assigned to the user holds user information to be generated in response to a viewing request from the user, and double viewing for the same user is restricted. . Further, in a large-scale video distribution system in which the number of users is 100,000 units, it is disadvantageous to retain user information redundantly because it is necessary to secure a large amount of capacity. In addition, by storing the user information only in the encryption key distribution server, this disadvantage can be avoided by a slight increase in load. Further, the present invention has an advantage that the mechanism and procedure for restoring the consistency of user information when a failure occurs in the encryption key distribution server or the viewing control server can be simplified.

It is a block diagram which shows the Example of this invention and shows the whole structure containing a video delivery system. It is a block diagram which shows the structure of the encryption key delivery server shown in FIG. It is a figure which shows the structural example of the user information database shown in FIG. It is a figure which shows the structural example of the encryption key database shown in FIG. It is a sequence diagram which shows the process sequence in the video delivery system by this invention. It is a figure which shows the analysis result of the load increase which generate | occur | produces by making a user information deletion request between encryption key distribution servers.

Explanation of symbols

10, 10a to 10c Viewing terminal 20 Local network 30 Viewing control server 40 Load distribution server 50, 50a to 50c Encryption key distribution server 51 Communication control unit 52 Encryption key generation unit 53 Encryption key distribution unit 54 User information management unit 58 Encryption key database 59 User Information Database 60 Video Distribution Server 90 Video Distribution Network 100 Video Distribution System 581-58m Encryption Key Array 591-59n User Information Piece

Claims (6)

A first encryption key that is a server that each distributes an encryption key corresponding to the encryption to a plurality of terminals to which encrypted content is distributed, each including distribution stop processing means and encryption key distribution stop means A distribution system including a distribution server and a second encryption key distribution server,
An encryption key that receives a first request signal generated based on a content viewing request from one of the plurality of terminals, and that assigns the first encryption key distribution server to the one terminal as an assigned encryption key distribution server Including distribution server allocation means,
The distribution stop processing means included in the first encryption key distribution server includes:
Distributing an encryption key used in the one terminal, and transmitting a distribution stop request signal designating the one terminal to the second encryption key distribution server;
The encryption key distribution stop means included in the second encryption key distribution server includes:
A video distribution system that receives the distribution stop request signal and stops distribution of an encryption key used in the one terminal. The distribution stop processing unit newly generates and holds a user information piece corresponding to the one terminal, starts distribution of the encryption key based on the content of the generated user information piece,
The encryption key distribution stop means deletes the user information piece when it is held by itself, and stops the distribution of the encryption key toward the one terminal based on the non-holding of the user information piece. The video distribution system according to claim 1, wherein:   The encryption key distribution server assigning means assigns the first encryption key distribution server to the assigned encryption key distribution server based on an expected load amount of the first encryption key distribution server and an expected load amount of the first encryption key distribution server. The video distribution system according to claim 1, wherein the video distribution system is assigned to the one terminal. A first encryption key, which is a server that each distributes an encryption key corresponding to the encryption to a plurality of terminals to which the encrypted content is distributed, each including distribution stop processing means and encryption key distribution stop means A system including a distribution server and a second encryption key distribution server, and a distribution method in a distribution system including encryption key distribution server allocation means in the system,
The encryption key distribution server assigning means includes
An encryption key that receives a first request signal generated based on a content viewing request from one of the plurality of terminals, and that assigns the first encryption key distribution server to the one terminal as an assigned encryption key distribution server Including a distribution server assignment step,
The distribution stop processing means included in the first encryption key distribution server includes:
Including a distribution stop processing step of distributing an encryption key used in the one terminal and transmitting a distribution stop request signal designating the one terminal to the second encryption key distribution server;
The encryption key distribution stop means included in the second encryption key distribution server includes:
A distribution method comprising: an encryption key distribution stop step of receiving the distribution stop request signal and stopping distribution of an encryption key used in the one terminal. The distribution stop processing step newly generates a user information piece corresponding to the one terminal, stores the user information piece in the second encryption key distribution server, and based on the content of the generated user information piece, Deliver the encryption key,
The encryption key distribution stop step deletes the user information piece when the user information piece is stored in the second encryption key distribution server, and distributes the encryption key used in the one terminal. The distribution method according to claim 4 , wherein the distribution method is stopped. The encryption key distribution server assigning step is configured such that the first encryption key distribution server is assigned to the assigned encryption key distribution server based on an expected load amount of the first encryption key distribution server and an expected load amount of the first encryption key distribution server. 5. The distribution method according to claim 4 , wherein the distribution method is assigned to the one terminal.

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