JP5455722B2 - Copyright protection device and copyright protection method - Google Patents

Description

  Embodiments described herein relate generally to a copyright protection device and a copyright protection method for obtaining a scramble key for decrypting encrypted content.

  There is an IPTV service (IP broadcast) that distributes content using an Internet protocol (IP). The content is encrypted and distributed, and the encrypted content is decrypted and reproduced when there is a right to reproduce.

  Patent Document 1 discloses a system in which a plurality of devices connected to a home network respectively download content from a Web server and reproduce the content under the restriction of the license downloaded from the license server.

  Also, in Patent Document 2, a server generates control information based on time information attached to content and distributes the control information to a terminal device, and the terminal device controls content playback based on the received control information. A control system is disclosed.

JP 2004-362546 A JP 2005-160032 A

  Generally, rather than determining whether a license is valid for each device, it is easier to determine whether the license is valid for one device, and sending the result of the determination to another device reduces the overall system load. it is conceivable that.

  However, consider an IPTV service in which pay broadcasting and free broadcasting are mixed, the scramble key is different for each channel, and the scramble key is updated every few seconds. In this case, it is necessary for one device to determine whether the license is valid every few seconds for all channels being received. Further, since the scramble key is transmitted in an encrypted state, it is necessary to decrypt the scramble key encrypted every few seconds for all channels being received. Therefore, the load on one device is concentrated.

  In Cited Document 1, a plurality of devices connected on the home network are taken as an example. However, there are applications in which a plurality of processors are provided in one apparatus, and each processor plays and records content. The same applies to the device to be executed. That is, a plurality of processors are provided in the apparatus, an application that performs a process of determining whether the license is valid is executed by one processor, and an application that performs a process of decrypting the scramble key is executed by another processor. In this case, the load on the application that performs the process of determining whether the license is valid is concentrated.

  An object of the present invention is to determine whether a license is within the expiration date based on time information acquired from a server, and to generate a scramble key for decrypting encrypted content when the license is within the expiration date An object of the present invention is to provide a copyright protection device and a copyright protection method capable of reducing the load on the application.

  A copyright protection device according to an example of the present invention includes a storage unit, a first processor that executes a first application that accesses the storage unit, and a second processor that executes a second application that accesses the storage unit. The first application includes a process for storing license data including a first work key and first expiration date data corresponding to the first encrypted content acquired from the first server in the storage unit; And a process of transmitting the time data acquired from the second application to the second application, wherein the second application scrambles the first encrypted content and the first encrypted content from the third server. Receiving a first stream including first control data including a first encrypted scramble key obtained by encrypting the key; When the first control data is received, the current time is calculated based on the time data transmitted from the first application, and the first expiration date data stored in the storage unit and the calculation The first control using the first work key stored in the storage unit when it is determined that it is within the expiration date and the processing for determining whether the expiration date is within the expiration date And a process of obtaining a first scramble key obtained by decrypting the first encrypted scramble key included in the data.

  A copyright protection method according to an example of the present invention includes license data including a first work key and first expiration date data corresponding to a first encrypted content from a first server by a first application executed by a first processor. And the license data is stored in the storage unit by the first application, the time data is acquired from the second server by the first application, and the second application is executed by the second processor from the first application. The first encrypted scramble key obtained by encrypting the first scramble key and the first scramble key for decrypting the first encrypted content and the first encrypted content from the third server by the second application. Receiving a stream including first control data including When the first control data is received, the second application calculates a current time based on the time data, and the second application stores the first expiration date data stored in the storage unit and the second application Based on the calculated time data, it is determined whether it is within the expiration date, and when it is determined that it is within the expiration date, the first work key stored in the storage unit by the second application is used. And obtaining a first scramble key obtained by decrypting the first encrypted scramble key included in the first control data.

  According to the present invention, it is possible to efficiently decrypt encrypted content by a plurality of applications.

The block diagram which shows the structure of the copyright protection apparatus concerning one Embodiment of this invention. The flowchart which shows the procedure of the process regarding the license data and time data which are performed by the master application after starting a copyright protection apparatus concerning one Embodiment of this invention. The flowchart which shows the procedure of a process when the slave application receives time data from a master application concerning one Embodiment of this invention. The flowchart which shows the procedure which acquires the scramble key for decoding the encrypted content which the copyright protection apparatus received from the content server concerning one Embodiment of this invention. The block diagram which shows the structure of the copyright protection system concerning one Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing an IPTV copyright protection system using a copyright protection apparatus according to an embodiment of the present invention.

  IPTV here refers to a copyright protection device that receives information such as a work key and a license expiration date as license data from a license server via a network in accordance with a predetermined copyright protection standard. The encrypted content (scrambled content) is received from the content server by multicast, and the encrypted scramble key in the ECM (Entitlement Control Message) packet (control data) included in the stream constituting the encrypted content is the work key. The TV service is characterized in that the encrypted content is decrypted (descramble) using the decrypted scramble key. An example of the IPTV copyright protection standard is Marlin (http://www.marlin-community.com/). Note that the above-mentioned license expiration date is a time limit for allowing decryption of encrypted content.

  The copyright protection apparatus 100 includes a master CPU 101, a memory 102, one or more slave CPUs 111, a memory 112, a network controller 121, a nonvolatile memory (storage unit) 130, a real-time clock (RTC) 141, and the like.

  The master CPU 101 is a processor, and executes various application programs such as a master application 103 loaded into a memory 102 from a storage device such as a hard disk drive (HDD).

  The slave CPU 111 is a processor, and executes various application programs such as the slave application 113 loaded into the memory 112 from a storage device such as a hard disk drive (HDD). Note that there may be a plurality of slave CPUs 111, and various application programs may be executed by each slave CPU 111.

  The master CPU 101 can access the memory 102, but cannot access the memory 112. The slave CPU 111 can access the memory 112 but cannot access the memory 102.

  Each of the master CPU 101 and the slave CPU 111 is composed of one or more CPU cores.

  The network controller 121 communicates with the content server 11 or the license server 12 via the Internet 10 in response to a command sent from the master application 103 or the slave application 113, and acquires data from the server that performed the communication. The acquired data is sent to the application that sent the command.

  The nonvolatile memory 130 stores license data 131 (to be described later) by the master application 103. The slave application 113 can access the nonvolatile memory 130 and can read the license data 131.

  The RTC 141 is a clock module that measures time (date and time), and operates with a battery dedicated to the RTC 141 even during a period in which the apparatus 100 is powered off.

  Both the master application 103 and the slave application 113 acquire a scramble key by decrypting an encrypted scramble key sent together with one or more encrypted contents received from the content server 11 by multicast using a work key, and the acquired scramble key The encrypted content is stored in an HDD (hard disk drive, storage unit) 150.

  In addition, both the master application 103 and the slave application 113 have a function of decrypting one or more encrypted contents received from the content server 11 by multicast or stored in the HDD 150 using a scramble key and playing the decrypted contents. . The reproduced video of the content is displayed on the display device 160. The multicast stream reception format may be a format that the master application 103 and the slave application 113 receive independently from the network, or a format that the master application 103 receives from the network and transfers to the slave application 113 via the inter-CPU connection bus. But you can. The inter-CPU connection bus is a general purpose bus.

  As an advantage of decrypting encrypted content by a plurality of applications, for example, by providing the master application 103 with a viewing function and the slave application 113 with a recording function, a plurality of back programs can be recorded simultaneously while viewing an IPTV program. . In addition, by providing both the master application 103 and the slave application 113 with a viewing function, it is possible to view a plurality of IPTV programs at the same time using a multi-window.

  The general-purpose bus is, for example, Ethernet (registered trademark). In this embodiment, the connection bus between CPUs is a general-purpose bus in order to emphasize the effect of encryption of time data acquired from the license server, but a dedicated bus may be used.

  The master application 103 acquires license data and time data used for determining the expiration date of the license from the license server 12. The license data includes the expiration date data of the license for each channel, the work key used for decrypting the scramble key, and the tier bit which is the contract existence data for each channel. The acquisition of time data from the license server 12 prevents the time of the RTC 141 in the copyright protection device 100 from being changed by a malicious user and using the scramble key illegally beyond the expiration date of the license. Because. The ECM packet includes a scramble key and channel data being received, which are encrypted with the work key.

  The license data 131 stored in the non-volatile memory 130 describes the expiration date of almost all services (channels and programs) in the IP broadcast. The expiration date of all services (channels, programs) in the license data 131 may be different for each service, and the master application 103 detects that the expiration date of any service expires and updates the license data 131.

  Next, a procedure of processing related to the license data 131 and time data executed by the master application 103 after the copyright protection apparatus 100 is activated will be described with reference to the flowchart of FIG.

  The master application 103 tries to read the license data stored in the nonvolatile memory 130 (step S11). The master application 103 determines whether the license data has been read (step S12). When there is no license data 131 in the nonvolatile memory 130 and the license data 131 cannot be read (No in step S12), the master application 103 displays an IPTV service registration screen on the display screen of the display device 160. (Step S13). A “registration” button is displayed on the IPTV service registration screen.

  When the “register” button is pressed by the user operating the remote controller or the like, the master application 103 detects that the “register” button has been operated (step S14). The master application 103 acquires license data and time data from the license server 12 (step S15). Then, the master application 103 writes the license data 131 to the nonvolatile memory 130 (step S16), and reads the license data 131 from the nonvolatile memory 130 (step S17).

  Then, the master application 103 encrypts the time data acquired in step S15 (step S18), and transmits the encrypted time data to the slave application 113 via the inter-CPU connection bus. When transmitting time data to a plurality of slave applications 113, the time data may be transmitted simultaneously to a plurality of slave applications 113 by broadcast, or may be sequentially transmitted to individual slave applications 113 by unicast. Any method can be used for encrypting time data as long as the encryption key can be shared between the master application 103 and the slave application 113. For example, there is a method in which each application holds a secret shared key.

  If it is determined in step S12 that the license data 131 has been read (Yes in step S12), the master application 103 sets the license expiration date because the time data has not been acquired from the license server 12. Time is acquired from the RTC 141 inside the copyright protection system as a temporary time for determination (step S20). Even if the time of the RTC 141 is falsified, the temporary time is only used for determining whether or not the license is acquired at the time of activation, and the master application 103 receives time data from the license server 12 as described later even if license acquisition is unnecessary. Therefore, the temporary time is not used for determining the license expiration date performed at a predetermined timing.

  Subsequently, the master application 103 determines whether the expiration date has passed by comparing the expiration date with the time acquired from the RTC 141 (step S21). When it is determined that the expiration date has passed (Yes in step S21), the master application 103 sequentially executes the processes from step S15.

  When the copyright protection apparatus 100 is temporarily stopped in a state where the license data 131 is written in the nonvolatile memory 130 and the copyright protection apparatus 100 is activated again, the license expiration date has already passed at the time of activation. (Yes in step S21) or near the expiration date (Yes in step S22). Therefore, when the copyright protection apparatus 100 is activated, the master application 103 reads the license data 131 from the non-volatile memory 130, and when the expiration date is about to expire or is about to expire, a license is acquired from the license server 12.

  When it is determined that the expiration date has not passed (No in step S21), the master application 103 determines whether the expiration date is approaching (step S22). For example, when the license data is acquired, the master application 103 acquires the next license acquisition time from the license server 12 as one of the license information, and when the time has passed the next license acquisition time, it is determined that the expiration date is about to expire. Alternatively, it may be determined that the expiration date is about to expire when the master application 103 passes a certain time before the expiration date set independently from the license server.

  When it is determined that the expiration date is approaching (Yes in step S22), the master application 103 sequentially executes the processing from step S15. When it is determined that the expiration date is not approaching (No in Step S22), the master application 103 determines whether or not a preset update cycle has passed (Step S23). When it is determined that the time data update cycle has not passed (No in step S23), the master application 103 sequentially executes the processing from step S22. If it is determined that the time data update period has passed (Yes in step S23), the master application 103 acquires time data from the license server (step S24). If time data is acquired, the process from step S18 will be performed sequentially.

  In this way, processing related to the license data 131 and time data executed by the master application 103 is performed.

  In order to prevent the expiration date of the license from being erroneously determined due to a time lag, it is necessary to acquire time data from the license server 12 more frequently than the license data update cycle. The master application 103 transmits the time data acquired from the license server 12 to the slave application 113 without writing the time data in the nonvolatile memory 130. Although the nonvolatile memory 130 has a lifetime with respect to the number of times of writing, by not writing time data to the nonvolatile memory 130, writing to the nonvolatile memory 130 can be minimized and the lifetime of the nonvolatile memory 130 can be extended. In particular, this is effective when the nonvolatile memory 130 is constituted by a flash memory (in particular, a multi-value flash memory).

  In addition, when the master application 103 writes license data to the nonvolatile memory 130, if the license data is encrypted, the nonvolatile memory 130 is illegally analyzed or a general purpose bus is connected to the application and the nonvolatile memory 130. Even if the general-purpose bus is illegally analyzed in a configuration in which the bus is interposed, unauthorized acquisition of license data can be prevented.

  Next, a processing procedure when the slave application 113 receives time data from the master application 103 will be described with reference to the flowchart of FIG.

  When the slave application 113 receives the encrypted time data (Yes in step S31), the slave application 113 decrypts the encrypted time data and acquires the time data acquired from the license server by the master application 103 (step S32). ). The slave application 113 reads the work key in the license data 131 and the license expiration date from the nonvolatile memory 130 (step S33).

  Next, a scramble key acquisition method for the copyright protection apparatus 100 to decrypt the encrypted content received from the content server 11 will be described with reference to the flowchart of FIG.

  For example, when the master application 103 detects an ECM packet in the multicast stream received from the content server 11 (Yes in step S41), the master application 103 presents the time data acquired from the license server 12 and the current time from the acquisition time. Time is calculated (step S42). The master application 103 determines whether the current time is within the validity period stored in the license data 131 read from the nonvolatile memory 130 (step S43).

  If it is within the validity period (Yes in step S43), the master application 103 is included in the received tier bit included in the ECM packet decrypted with the work key stored in the license data 131 and the license data. To determine whether or not there is a contract for the channel being received (step S44). If it is determined that there is a contract for the channel being received, the master application 103 acquires the scramble key by decrypting the encrypted scramble key included in the ECM packet with the work key read from the nonvolatile memory 130 (step S45). If the master application 103 caches the license data 131 in the memory 102 in step S17, the cached license data 131 may be used in steps S44 and S45, so that the frequency of access to the nonvolatile memory 131 can be reduced. . In the above description, the operation of the master application has been described, but the same applies to the slave application 113.

  Since the copyright protection apparatus 100 and the license server operate with independent RTCs, the master application 103 / slave application 113 will shift in time (time) when operated for a long time. In order to eliminate the synchronization of time (time), the master application 103 acquires the time from the license server 12 in a cycle set in advance in the copyright protection device 100 even if the license is within the expiration date. Even when the copyright protection apparatus 100 is activated, it is considered that it corresponds to the update cycle. When the master application 103 acquires time data from the license server 12, the master application 103 encrypts the time data and transmits it to the slave application 113.

  In the above description, the license acquisition operation for one IPTV service has been described. However, when an area for writing license data is prepared for each IPTV service in the nonvolatile memory 130 and the master application 103 transmits time data to the slave license. If the IPTV service type and time data are transmitted in association with each other and the master application 103 and the slave application 113 manage the time for each IPTV service, one copyright protection device 100 can handle a plurality of different IPTV services. Can do.

  In the present embodiment, a case where one application operates on one CPU is described. However, even when a plurality of applications operate on one CPU, the application is executed from the license server 12 by the master application 103 in the same procedure. Acquired license data can be read.

  By writing the license data 131 to the nonvolatile memory 130 and transmitting time data for determining the expiration date from the master application 103 to the slave application 113, the load on the master application can be reduced.

  In the above embodiment, an example in which the master application 103 and the slave application 113 are executed in one apparatus 100 has been described. However, the master application 103 and the slave application 113 may be executed in different apparatuses.

  FIG. 5 shows an example configuration in which the master application 103 and the slave application 113 are executed by different apparatuses.

  As shown in FIG. 5, a first copyright protection device 100 </ b> A and a second copyright protection device 100 </ b> B are connected to the Internet 10 via a hub (HUB) 200. The first copyright protection device 100A includes a master CPU 101, a memory 102, a network controller 121A, a nonvolatile memory 130, a real-time clock (RTC) 141A, and the like. The second copyright protection device 100B includes a slave CPU 111, a memory 112, a network controller 121B, a real time clock (RTC) 141B, and the like.

  The main CPU 101 is a processor, and executes various application programs such as a master application 103 loaded into a memory 102 from a storage device such as a hard disk drive (HDD).

  The network controllers 121A and 121B communicate with the content server 11 or the license server 12 via the Internet 10 in response to a command sent from the master application 103 or the slave application 113, and acquire data from the server that performed the communication. . The acquired data is sent to the application that sent the command.

  The first copyright protection device 100A and the second copyright protection device 100B are connected to the Internet 10 via the switching hub 200. In addition, the first copyright protection device 100A and the second copyright protection device 100B can communicate via the switching hub 200.

  Note that the slave application 113 can access the nonvolatile memory 130 via the switching hub 200 and acquire the license data 131. The slave application 113 accesses the non-volatile memory 130 from the lower layer of the communication protocol with respect to the master application 103, so that no load is applied to the master CPU 101 (master application 103). That is, the slave can acquire the license data without imposing a burden on the master CPU 101 (master application 103).

  The first copyright protection device 100A is executed by, for example, a set top box or a home server, and the second copyright protection device 100B is realized by, for example, a television or a hard disk drive recorder.

  In the above embodiment, the case where the license server 12 provides the license data and the time data has been described. However, the server that provides the license data and the time data may be different.

  Also, the above description has been made on the license acquisition operation for one IPTV service. However, when an area for writing license data is prepared in the nonvolatile memory for each IPTV service, and the master application transmits time data to the slave application. If the IPTV service type and time data are transmitted in association with each other and the master application and slave application manage the time for each IPTV service, one copyright protection device can handle a plurality of different IPTV services.

  In the above-described embodiment, a case where one application operates on one CPU is described. Even when a plurality of applications operate on one CPU, the application is a master application and the license server is processed in the same procedure. The license acquired from can be read.

  In the above embodiment, each of the content server 11 and the license server 12 is a single server, but a content server and a license server may be provided for each service (channel, program) in the IPTV service. .

  In the above embodiment, the case where there is one content server (content service provider) that provides the IPTV service has been described. However, there may be a plurality of content servers that provide the IPTV service. In this case, since the license data differs depending on the content server, the master application 103 acquires the license server and time data from the license server corresponding to each content server. Also, the master application 103 and the slave application 113 can acquire encrypted contents from different servers, respectively, and can acquire a license key corresponding to each encrypted content. When the master application 103 acquires time data from the license server, the master application 103 manages the time data in association with the license server (or content server), and manages the time data associated with the license server (or content server) as a slave. Transmit to the application 113.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

  DESCRIPTION OF SYMBOLS 10 ... Internet, 11 ... Content server, 12 ... License server, 100 ... Copyright protection apparatus, 101 ... Master CPU, 102 ... Memory, 103 ... Master application, 111 ... Slave CPU, 112 ... Memory, 113 ... Slave application, 121 DESCRIPTION OF SYMBOLS ... Network controller, 130 ... Non-volatile memory (memory | storage part), 131 ... License data, 141 ... Real time clock, 150 ... Hard disk drive (2nd memory | storage device), 160 ... Display apparatus.

Claims (6)

A storage unit;
A first processor that executes a first application that accesses the storage unit;
A second processor that executes a second application that accesses the storage unit;
The first application acquires from the second server a process of storing license data including the first work key and the first expiration date data corresponding to the first encrypted content acquired from the first server in the storage unit. Processing to send time data to the second application,
The second application receives from the third server the first encrypted content and first control data including a first encrypted scramble key obtained by encrypting a first scramble key for decrypting the first encrypted content. A process of receiving a first stream including the first stream, and when the first control data is received, a current time is calculated based on time data transmitted from the first application, and stored in the storage unit A process for determining whether it is within the expiration date based on one expiration date data and the calculated time, and a first work key stored in the storage unit when it is determined that it is within the expiration date Performing a process of obtaining a first scramble key obtained by decrypting the first encrypted scramble key included in the first control data using Copyright protection apparatus according to claim.   The copyright protection apparatus according to claim 1, wherein the second application executes a process of storing the first encrypted content and the first scramble key in a storage unit different from the storage unit.   The copyright according to claim 1, wherein the second application executes a process of reproducing the first content obtained by decrypting the first encrypted content using the first scramble key. Protective device.   The copyright protection according to claim 1, wherein the first application executes a process of encrypting the time data and a process of transmitting the encrypted time data to the second application. apparatus. The license data includes a second work key and second expiration date data corresponding to the second encrypted content,
The first application includes second control data including a second encrypted scramble key obtained by encrypting the second encrypted content and the second scramble key for decrypting the second encrypted content from the third server; A process of receiving a second stream including: a process of calculating a current time based on time data acquired from the second server when the second control data is received; and A process for determining whether it is within the expiration date based on the second expiration date data and the calculated time, and when it is determined that it is within the expiration date, the second stored in the storage unit A process of acquiring the second scramble key obtained by decrypting the second encrypted scramble key included in the second control data using two work keys. Copyright protection apparatus according to claim 1, characterized in Rukoto. The first application executed by the first processor acquires license data including the first work key corresponding to the first encrypted content and the first expiration date data from the first server,
The license data is stored in a storage unit by the first application,
Obtaining time data from the second server by the first application;
Sending the time data from the first application to a second application executed by a second processor;
A first control data including a first encrypted scramble key obtained by encrypting the first scramble key for decrypting the first encrypted content and the first encrypted content from a third server by the second application; Receive the stream,
When receiving the first control data, the second application calculates the current time based on the time data,
Determining whether it is within the expiration date based on the first expiration date data stored in the storage unit by the second application and the calculated time data;
When it is determined that it is within the expiration date, the first encryption scramble key included in the first control data is decrypted by using the first work key stored in the storage unit by the second application. A copyright protection method, comprising: obtaining a first scramble key obtained by

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