Receiving device, terminal device, control method, and transmitting device

Abstract

The present invention relates to a reception device, a terminal device, a control method, and a transmission device, configured so that it is possible to more easily make encoded content delivered on differing paths viewable. The reception device provided comprises: a reception unit that receives first encoded content delivered via a first transmission path; a first decoding unit that uses a first key included in a first message delivered via the first transmission path to decode the first encoded content; and a control unit that controls the operation of the reception unit and the first decoding unit. The first message is encoded with a second key included in a second message delivered via the first transmission path. The control unit controls so that the second key is provided to a second decoding unit that decodes second encoded content delivered via a second transmission path. The present invention is applicable, for example, to a television receiver.

Description

Technical Field

[0001] The present technology relates to a receiving device, a terminal device, a control method, and a transmitting device, and more particularly to a receiving device, a terminal device, a control method, and a transmitting device that can more easily make encrypted content distributed via different paths viewable.

Background Art

[0002] In recent years, with the spread of mobile devices such as smartphones and tablet terminals, mobile devices have been used as second screen terminals for television receivers. In digital broadcasting, technologies for protecting content such as a conditional access system (CAS) are adopted (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When using a second screen terminal and decrypting encrypted content distributed via a different path from a television receiver, it is necessary to support a conditional access system (CAS) on the second screen terminal side. Therefore, there has been a demand to more easily make encrypted content distributed via different paths viewable.

[0005] The present technology has been made in view of such a situation, and enables more easily making encrypted content distributed via different paths viewable.

Means for Solving the Problems

[0006] The receiving device according to one aspect of the present technology includes a receiving unit that receives first encrypted content distributed via a first transmission path, a first decryption unit that decrypts the first encrypted content using a first key included in a first message distributed via the first transmission path, and a control unit that controls the operations of each unit. The first message is encrypted with a second key included in a second message distributed via the first transmission path, and the control unit is a receiving device that controls to provide the second key to a second decryption unit that decrypts second encrypted content distributed via a second transmission path.

[0007] According to a control method of one aspect of the present technology, a receiving device decrypts first encrypted content distributed via a first transmission path using a first key included in a first message distributed via the first transmission path, and controls to provide a second key included in a second message distributed via the first transmission path to a second decryption unit that decrypts second encrypted content distributed via a second transmission path, and the first message is encrypted with the second key.

[0008] In the receiving device and the control method according to one aspect of the present technology, the first encrypted content distributed via the first transmission path is decrypted using the first key included in the first message distributed via the first transmission path, and control is performed so that the second key included in the second message distributed via the first transmission path is provided to the second decryption unit that decrypts the second encrypted content distributed via the second transmission path. Further, the first message is encrypted with the second key.

[0009] A terminal device according to an aspect of the present technology includes a holding unit that holds a second key provided from a receiving device having a first decryption unit that decrypts first encrypted content distributed via a first transmission path, a receiving unit that receives second encrypted content distributed via a second transmission path, and a second decryption unit that decrypts the second encrypted content using a first key included in a first message distributed via the second transmission path. The first message is encrypted with the second key, and the first key is obtained by decrypting the first message using the second key held by the holding unit.

[0010] A control method according to an aspect of the present technology is a control method in which a terminal device holds a second key provided from a receiving device having a first decryption unit that decrypts first encrypted content distributed via a first transmission path, decrypts second encrypted content distributed via the second transmission path using a first key included in a first message distributed via the second transmission path, the first message is encrypted with the second key, and the first key is obtained by decrypting the first message using the held second key.

[0011] In a terminal device and a control method according to an aspect of the present technology, a second key provided from a receiving device having a first decryption unit that decrypts first encrypted content distributed via a first transmission path is held, and second encrypted content distributed via the second transmission path is decrypted using a first key included in a first message distributed via the second transmission path. Further, the first message is encrypted with the second key, and the first key is obtained by decrypting the first message using the held second key.

[0012] The transmission device according to one aspect of the present technology includes a generation unit that generates a first message including a first key for decrypting second encrypted content distributed via a second transmission path, and a transmission unit that transmits the first message via the second transmission path. The first message is encrypted with the same second key as the first message including the first key for decrypting the first encrypted content distributed via the first transmission path.

[0013] In the transmission device according to one aspect of the present technology, a first message including a first key for decrypting second encrypted content distributed via a second transmission path is generated, and the first message is transmitted via the second transmission path. Further, the first message is encrypted with the same second key as the first message including the first key for decrypting the first encrypted content distributed via the first transmission path.

[0014] Note that the receiving device, the terminal device, and the transmission device according to one aspect of the present technology may be independent devices or internal blocks constituting one device.

Brief Description of Drawings

[0015]

Figure 1

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[0016] <1. First Embodiment>

[0017] (System Configuration) FIG. 1 shows a first example of the configuration of a content distribution system to which the present technology is applied.

[0018] In FIG. 1, the content distribution system includes a transmitting-side (broadcasting station side) device composed of a broadcast transmission device 10 and a stream server 20, and a receiving-side device composed of a receiving device 30 and a second screen terminal device 40.

[0019] The broadcast transmission device 10 transmits broadcast content as a broadcast signal via a broadcast transmission path according to a predetermined broadcast method. The broadcast content is a broadcast program produced by each broadcasting station, and includes, for example, a paid broadcast program such as PPV (Pay Per View). The broadcast method conforms to the standards of digital broadcasts such as terrestrial digital television, broadcasting satellite (BS: Broadcasting Satellite) or communication satellite (CS: Communications Satellite), or cable television (CATV) using a cable.

[0020] The stream server 20 transmits communication content via the network 90 according to a predetermined communication method. The stream server 20 is provided by a broadcasting station or the like. The communication content includes various programs such as broadcast programs produced by each broadcasting station. The network 90 is a communication transmission path including communication networks such as the Internet, intranet, and mobile phone network.

[0021] The receiving device 30 is a device such as a television receiver having a function corresponding to a predetermined broadcasting method. The receiving device 30 receives and processes a broadcast signal transmitted from the broadcast transmitting device 10 via a broadcast transmission path, enabling viewing of broadcast content. Further, the receiving device 30 has a function corresponding to a predetermined communication method and communicates with other devices such as the second screen terminal device 40.

[0022] The second screen terminal device 40 is a device such as a mobile device like a smartphone or a tablet terminal having a function corresponding to a predetermined communication method. The second screen terminal device 40 is used as the second screen terminal of the receiving device 30. The second screen terminal device 40 receives and processes data transmitted from the stream server 20 via the network 90, enabling viewing of communication content. Further, the second screen terminal device 40 communicates with other devices such as the receiving device 30.

[0023] Note that the transmitting-side devices including the broadcast transmitting device 10 and the stream server 20 can exchange various data via a predetermined network. The receiving-side devices including the receiving device 30 and the second screen terminal device 40 are used at the user's home or the like and can communicate with each other via a predetermined wireless communication or the like.

[0024] In the content distribution system shown in FIG. 1, a conditional access system (CAS) is adopted, and content is protected according to a predetermined content rights protection method. Hereinafter, content encrypted using CAS is referred to as encrypted content. In the content distribution system shown in FIG. 1, audio data and video data included in an AV stream are encrypted by a device on the transmitting side using a scramble key (Ks), while the encrypted audio data and video data are decrypted by a device on the receiving side using the scramble key (Ks).

[0025] Also, the device on the transmitting side distributes an EMM (Entitlement Management Message) as related information of the identification unit of the device on the receiving side and an ECM (Entitlement Control Message) as related information common to each device on the receiving side to the device on the receiving side at a predetermined interval. That is, the EMM is an individual message, and the ECM is a common message. An example of the configuration of the EMM and ECM is shown in FIG. 2.

[0026] The EMM is composed of an encrypted part and an unencrypted part. In the EMM, the encrypted part is encrypted by a device key (Kd), and a work key (Kw) is arranged therein. In addition to the work key (Kw), information such as a work key ID (KwID) and device key update information may be arranged in the encrypted part. Information such as a device ID, protocol number, business entity identification, and update number can be arranged in the unencrypted part.

[0027] The ECM is composed of an encrypted part and an unencrypted part. In the ECM, the encrypted part is encrypted using the work key (Kw), and a scramble key (Ks) is arranged therein. Information such as a protocol number, business entity identification, and work key ID (KwID) can be arranged in the unencrypted part.

[0028] In the receiving device, the EMM and ECM distributed from the transmitting device are acquired at a predetermined timing. First, in the receiving device, the work key (Kw) is acquired by decrypting the encrypted part of the EMM using the device key (Kd). Then, in the receiving device, the scrambling key (Ks) is acquired by decrypting the encrypted part of the ECM using the work key (Kw). Then, in the receiving device, the encrypted data of the AV stream distributed from the transmitting device is decrypted using the scrambling key (Ks).

[0029] Note that the work key (Kw) distributed by the EMM has a longer update interval than the scrambling key (Ks) and is updated, for example, about once a month. The scrambling key (Ks) distributed by the ECM is updated in a short time such as about one second. The device key (Kd) is held in advance by the receiving device 30. Here, the case where the device key (Kd) is used as the key for decrypting the encrypted part of the EMM is shown, but the device key (Kd) can also be said to be an individual master key (Km) for each receiver managed by a key management center or the like.

[0030] Figure 3 shows an example of the detailed configuration of the receiving device of the content distribution system in Figure 1.

[0031] In Figure 3, the receiving device 30 includes a control unit 300, a tuner 301, a descrambler 302, a demultiplexer 303, a CAS system 304, a decoder 305, an output unit 306, and a communication unit 307.

[0032] The control unit 300 has a processor such as a CPU (Central Processing Unit). The control unit 300 is a central control device that controls the operations of each unit and performs various arithmetic processes.

[0033] The tuner 301 demodulates the broadcast signal received by an antenna (not shown) and supplies the resulting multiplexed stream to the descrambler 302.

[0034] The descrambler 302 processes the multiplexed stream supplied from the tuner 301, decrypts the encrypted data of the AV stream using the scrambling key (Ks) from the CAS system 304, and supplies the decrypted multiplexed stream to the demultiplexer 303.

[0035] The demultiplexer 303 separates the audio data and video data included in the multiplexed stream supplied from the descrambler 302 and supplies them to the decoder 305. Also, the demultiplexer 303 supplies the control information included in the multiplexed stream to the control unit 300 or the CAS system 304. The control information includes information such as channel selection information and messages.

[0036] The CAS system 304 has functions related to the CAS. The CAS system 304 performs CAS-related processing using information such as messages supplied from the demultiplexer 303 in accordance with the control from the control unit 300.

[0037] When the EMM is supplied, the CAS system 304 decrypts its encrypted part using the device key (Kd) and obtains the work key (Kw). The CAS system 304 holds the obtained work key (Kw) in a holding unit (such as an internal memory) and supplies it to the communication unit 307. Also, when the ECM is supplied, the CAS system 304 decrypts its encrypted part using the work key (Kw) and obtains the scrambling key (Ks). The CAS system 304 supplies the obtained scrambling key (Ks) to the descrambler 302.

[0038] The decoder 305 has an audio decoder and a video decoder compliant with a predetermined decoding method. The decoder 305 decodes the audio data supplied from the demultiplexer 303 and supplies it to the output unit 306. The decoder 305 decodes the video data supplied from the demultiplexer 303 and supplies it to the output unit 306.

[0039] The output unit 306 has a display and a speaker. The output unit 306 outputs sound (voice) corresponding to the audio data supplied from the decoder 305 from the speaker. The output unit 306 displays video corresponding to the video data supplied from the decoder 305 on the display.

[0040] The communication unit 307 has a communication module compliant with a predetermined communication method. The communication unit 307 communicates with other devices such as the second screen terminal device 40 by a predetermined communication method according to the control from the control unit 300. The communication unit 307 transmits the work key (Kw) supplied from the CAS system 304 to the second screen terminal device 40.

[0041] The communication methods include wireless communications such as wireless LAN (Local Area Network), short-range wireless communications such as Bluetooth (registered trademark), cellular communications such as LTE-Advanced and 5G, and wired communications such as Ethernet (registered trademark).

[0042] In FIG. 3, the second screen terminal device 40 has a control unit 400, a communication unit 401, a work key holding unit 402, a communication unit 403, a decoding unit 404, a decoder 405, and an output unit 406.

[0043] The communication unit 401 has a communication module compliant with a communication method such as wireless LAN or short-range wireless communication. The communication unit 401 communicates with other devices such as the receiving device 30 by a predetermined communication method according to the control from the control unit 400.

[0044] The work key holding unit 402 has a semiconductor memory such as a RAM (Random Access Memory). When the work key (Kw) transmitted from the receiving device 30 (its communication unit 307) is received by the communication unit 401, the work key holding unit 402 stores and holds the work key (Kw) supplied from the communication unit 401.

[0045] The communication unit 403 has a communication module compliant with a communication method such as a wireless LAN. The communication unit 403 communicates with other devices such as the stream server 20 via the network 90 by a predetermined communication method according to the control from the control unit 400.

[0046] The communication unit 403 receives the ECM transmitted from the stream server 20 and supplies it to the work key holding unit 402. The work key holding unit 402 uses the held work key (Kw) to decrypt the encrypted part of the ECM from the communication unit 403 and supplies the resulting scramble key (Ks) to the decoding unit 404.

[0047] The communication unit 403 supplies the AV stream transmitted from the stream server 20 to the decoding unit 404. The decoding unit 404 decrypts the encrypted data of the AV stream supplied from the communication unit 403 using the scramble key (Ks) from the work key holding unit 402 and supplies the resulting audio data and video data to the decoder 405.

[0048] The decoder 405 has an audio decoder and a video decoder compliant with a predetermined decoding method. The decoder 405 decodes the audio data supplied from the decoding unit 404 and supplies it to the output unit 406. The decoder 405 decodes the video data supplied from the decoding unit 404 and supplies it to the output unit 406.

[0049] The output unit 406 has a display and a speaker. The output unit 406 outputs sound corresponding to the audio data supplied from the decoder 405 from the speaker. The output unit 406 displays video corresponding to the video data supplied from the decoder 405 on the display.

[0050] Note that the configurations of the receiving device 30 and the second screen terminal device 40 shown in FIG. 3 are merely examples, and other components may be added or some of the components may be deleted. For example, in the second screen terminal device 40 shown in FIG. 3, the communication unit 401 and the communication unit 403 are configured separately, but they may be configured as one communication unit. In FIG. 1, only one set of the receiving device 30 and the second screen terminal device 40 is illustrated, but actually, a set of the receiving device 30 and the second screen terminal device 40 is provided for each user.

[0051] (Sequence flow) FIG. 4 shows a first example of a sequence representing the interaction between the devices constituting the content distribution system of FIG. 1 in chronological order. In the sequence of FIG. 4, the direction of time is from the upper side to the lower side.

[0052] FIG. 4 shows the data flow of the interaction between the transmitting devices consisting of the broadcast transmission device 10 and the stream server 20 and the receiving devices consisting of the receiving device 30 and the second screen terminal device 40.

[0053] In the receiving device 30, the application A1 and the CAS platform P1 are operating, and the flow of their operations is shown in FIG. 4. The application A1 and the CAS platform P1 operate in cooperation with the respective components of the receiving device 30 shown in FIG. 3.

[0054] In the second screen terminal device 40, the application A2 and the CAS platform P2 are operating, and the flow of their operations is shown in FIG. 4. The application A2 and the CAS platform P2 operate in cooperation with the respective components of the second screen terminal device 40 shown in FIG. 3.

[0055] Application A1 is a resident application pre-installed in the receiving device 30. Application A2 is an application for watching broadcast programs or the like, and is installed in the second screen terminal device 40 according to the user's operation. The CAS platforms P1 and P2 are provided by the CAS system 304 of the receiving device 30, and operations related to the CAS are performed.

[0056] The sequence in FIG. 4 is divided into three phases: a device connection phase (S1) performed among receiving-side devices before watching a program, a broadcast program viewing phase (S2) performed when watching broadcast content, and a communication program viewing phase (S3) performed when watching communication content.

[0057] In the device connection phase (S1), the broadcast transmission device 10 transmits the EMM via the broadcast transmission path (S11). The EMM transmitted from the broadcast transmission device 10 is received by the receiving device 30.

[0058] In the receiving device 30, the application A1 acquires the received EMM. The CAS platform P1 holds a working key (Kw) obtained by decrypting the encrypted part of the acquired EMM with the device key (Kd) (S12).

[0059] In the receiving device 30 and the second screen terminal device 40, the applications A1 and A2 perform predetermined processing on each other, are connected according to a predetermined communication method, and device authentication is performed (S13). Here, by connecting to and authenticating the CAS system 304 of the receiving device 30, the second screen terminal device 40 encrypts the communication path between the receiving device 30 and the second screen terminal device 40.

[0060] In the receiving device 30, the CAS platform P1 transmits the work key (Kw) held in the process of step S12 to the second screen terminal device 40. The work key (Kw) transmitted from the receiving device 30 is received by the second screen terminal device 40 and held in the CAS platform P2 (S14). Here, contract information may be transmitted and held together with the work key (Kw).

[0061] In this way, in the device connection phase (S1), the second screen terminal device 40 connects to the CAS system 304 of the receiving device 30 and is authenticated, so that secure communication is performed between the receiving device 30 and the second screen terminal device 40, and a common work key (Kw) is held respectively.

[0062] Next, in the broadcast program viewing phase (S2), the broadcast transmission device 10 transmits the ECM via the broadcast transmission path (S21). The ECM transmitted from the broadcast transmission device 10 is received by the receiving device 30. The ECM is included in the multiplexed stream. The encrypted part of the ECM is encrypted using the work key (Kw).

[0063] In the receiving device 30, the application A1 acquires the received ECM and injects (inputs) it into the CAS platform P1 (S22). The CAS platform P1 notifies the application A1 of the scramble key (Ks) obtained by decrypting the encrypted part of the ECM using the work key (Kw) held in the device connection phase (S12 of S1) (S23). When decrypting the encrypted part of the ECM, a determination process using contract information may be performed, and the scramble key (Ks) may be acquired according to the contract status.

[0064] The broadcast transmission device 10 transmits the AV stream of the broadcast content via the broadcast transmission path (S24). The AV stream transmitted from the broadcast transmission device 10 is received by the receiving device 30. The AV stream is included in the multiplexed stream. The encrypted data included in the AV stream is encrypted using the scramble key (Ks).

[0065] In the receiving device 30, the application A1 decrypts the encrypted data included in the AV stream using the scrambling key (Ks) from the CAS platform P1. In the receiving device 30, the decrypted audio data and video data are decoded, and the audio and video of the broadcast content are output. As a result, the user can view broadcast content such as a broadcast program.

[0066] As described above, in the broadcast program viewing phase (S2), when the user views the broadcast content, the encrypted data of the AV stream distributed via the broadcast transmission path is decrypted. At the time of this decryption, the scrambling key (Ks) obtained by decrypting the encrypted part of the ECM distributed via the broadcast transmission path with the working key (Kw) held in the device connection phase (S1) is used.

[0067] Next, in the communication program viewing phase (S3), in response to a viewing request from the second screen terminal device 40, the stream server 20 transmits an ECM as a common message via the network 90 (S31, S32). The ECM transmitted from the stream server 20 is received by the second screen terminal device 40. The encrypted part of the ECM as a common message is encrypted using the same working key (Kw) as in the broadcast program viewing phase (S2).

[0068] In the second screen terminal device 40, the application A2 acquires the received ECM and injects (inputs) it into the CAS platform P2 (S33). The CAS platform P2 notifies the application A2 of the scrambling key (Ks) obtained by decrypting the encrypted part of the ECM using the working key (Kw) held in the device connection phase (S14 of S1) (S34). Note that at the time of decrypting the encrypted part of the ECM, a determination process using the contract information held in the process of step S14 may be performed.

[0069] The stream server 20 transmits the AV stream of the communication content to the second screen terminal device 40 via the network 90 (S35). The AV stream transmitted from the stream server 20 is received by the second screen terminal device 40. The encrypted data included in the AV stream is encrypted using the same scrambling key (Ks) as in the broadcast program viewing phase (S2).

[0070] In the second screen terminal device 40, the application A2 decrypts the encrypted data included in the AV stream using the scrambling key (Ks) from the CAS platform P2. In the second screen terminal device 40, the audio data and video data are decoded, and the audio and video of the communication content are output. Thereby, the user can view communication content such as a broadcast program.

[0071] Thus, in the communication program viewing phase (S3), when the user views the communication content, the encrypted data of the AV stream distributed via the communication transmission path is decrypted. In this decryption, the scrambling key (Ks) obtained by decrypting the encrypted part of the ECM distributed via the communication transmission path based on the work key (Kw) held in the device connection phase (S1) is used.

[0072] In other words, in the communication program viewing phase (S3), when the second screen terminal device 40 connects to the stream server 20, the communication transmission path is encrypted by the work key (Kw) held in the device connection phase (S1). Also, the stream server 20 encrypts the communication content using the scrambling key (Ks). Thereby, secure communication is performed between the stream server 20 and the second screen terminal device 40.

[0073] In the above description, in the communication program viewing phase (S3), the case where the scramble key (Ks) used for encrypting the communication content is the same as the scramble key (Ks) included in the encryption section of the ECM distributed via the broadcast transmission path has been shown. However, not limited to the same scramble key (Ks), a scramble key (Ks') generated by a different algorithm may be used.

[0074] As described above, in this technology, the receiving device 30 such as a television receiver causes the second screen terminal device 40 used as a second screen terminal to hold the working key (Kw) obtained by decrypting the EMM as an individual message distributed via the broadcast transmission path. Thus, in the second screen terminal device 40, the ECM as a common message distributed via the communication transmission path is decrypted using the held working key (Kw). Then, in the second screen terminal device 40, the encrypted content distributed via the communication transmission path can be decrypted using the scramble key (Ks) obtained by decrypting the ECM as a common message.

[0075] Also, in this technology, the transmitting device which is the stream server 20 (or the broadcast transmission device 10) has a generation unit that generates an ECM as a common message including a scramble key (Ks) for decrypting the encrypted content distributed via the communication transmission path (or the broadcast transmission path), and a transmission unit that transmits the ECM as the common message via the communication transmission path (or the broadcast transmission path). The same working key (Kw) as that of the common message (ECM) including the scramble key (Ks) for decrypting the encrypted content distributed via the broadcast transmission path (or the communication transmission path) is encrypted in the ECM as the common message.

[0076] That is, the second screen terminal device 40 holds the working key (Kw) of the CAS system 304 built in the receiving device 30, and decrypts the encrypted content with the scramble key (Ks) obtained using the working key (Kw), enabling viewing of communication content such as broadcast programs.

[0077] In the second screen terminal device 40, since the scrambling key (Ks) can be obtained using the work key (Kw) from the CAS system 304 of the receiving device 30, it is possible to more easily make the encrypted content viewable without implementing a dedicated signal processing circuit such as a dedicated CAS system or descrambler for making the encrypted content viewable.

[0078] Note that since the key information (work key (Kw)) required by the CAS system cannot be written in advance in the application A2 installed in the second screen terminal device 40, in the device connection phase (S1), the receiving device 30 writes the key information (work key (Kw)) to the second screen terminal device 40.

[0079] Viewing of encrypted content such as a broadcast program is managed for each CAS system 304 (including, for example, a B-CAS card) of the receiving device 30. Therefore, in order to make the encrypted content viewable on the second screen terminal device 40, a system for managing contract information such as a CAS system ID is generally required separately. However, by using this technology, the encrypted content can be made viewable more easily without using such a system. Also, when viewing encrypted content on a second screen terminal such as a smartphone or tablet terminal, it is generally necessary for the broadcasting station to perform authentication by a CAS server separately from the broadcast CAS system. However, by using this technology, the encrypted content can be made viewable more easily without using such authentication.

[0080] When the user (viewer) views encrypted content such as a broadcast program using the second screen terminal device 40, procedures such as registration for viewing become unnecessary. Since such procedures can be omitted, the user can increase the opportunity to view encrypted content such as a broadcast program using the second screen terminal device 40.

[0081] <2. Second Embodiment>

[0082] (System Configuration) FIG. 5 shows a second example of the configuration of a content delivery system to which the present technology is applied.

[0083] In FIG. 5, compared with the configuration shown in FIG. 1, as devices on the transmission side, in addition to the broadcast transmission device 10 and the stream server 20, a license server 50 is provided. In the configuration shown in FIG. 5, parts corresponding to the configuration shown in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0084] The receiving device 30 is a device such as a television receiver having a function corresponding to a predetermined broadcast system and a function corresponding to a predetermined communication system. The receiving device 30 receives a license transmitted from the license server 50 via the network 90 and transmits (transfers) it to the second screen terminal device 40.

[0085] The license server 50 distributes a license via the network 90 in accordance with a predetermined communication system. The license is a license for making encrypted content viewable. An example of the configuration of the license is shown in FIG. 6.

[0086] The license is composed of an encrypted part and a non-encrypted part. In the license, the encrypted part is encrypted using the master key (Km), and information such as a license key and an expiration date is arranged therein. Information such as an ID for identifying the CAS platform and an ID for identifying the license can be arranged in the non-encrypted part.

[0087] In the receiving device, the EMM, ECM, and license distributed from the transmitting device are acquired at a predetermined timing. First, in the receiving device, the work key (Kw) is acquired by decrypting the encrypted part of the EMM using the device key (Kd). Then, in the receiving device, a determination process is performed to compare the reference license key obtained by decrypting the encrypted part of the ECM using the work key (Kw) with the license key obtained by decrypting the encrypted part of the license using the master key (Km).

[0088] For example, in this determination process, it is determined whether the current time arranged in the encrypted part of the ECM is within the expiration date arranged in the encrypted part of the license, and whether the reference license key and the license key match. When it is determined that the determination condition is satisfied, the scramble key (Ks) arranged in the encrypted part of the ECM is acquired. In this example, by using the current time of the ECM, even when the time measured by the receiving device is not accurately measured, the expiration date can be reliably determined.

[0089] In the receiving device, the encrypted data of the AV stream distributed from the transmitting device is decrypted using the scramble key (Ks) acquired according to the determination process.

[0090] (Sequence flow) FIG. 7 shows a second example of a sequence representing the communication between the devices constituting the content distribution system of FIG. 5 in chronological order.

[0091] In FIG. 7, the data flow of the communication between the transmitting devices composed of the broadcast transmission device 10, the stream server 20, and the license server 50 and the receiving devices composed of the receiving device 30 and the second screen terminal device 40 is shown. In the receiving device 30, the application A1 and the CAS platform P1 are operating. In the second screen terminal device 40, the application A2 and the CAS platform P2 are operating.

[0092] Similar to the sequence in FIG. 4, the sequence in FIG. 7 is divided into three phases: a device connection phase (S101), a broadcast program viewing phase (S102), and a communication program viewing phase (S103).

[0093] In the device connection phase (S101), in steps S111 to S113, similar to steps S11 to S14 in FIG. 4, secure communication is performed between the receiving device 30 and the second screen terminal device 40, and a common work key (Kw) is held by each.

[0094] In the second screen terminal device 40, when the application A2 is instructed to view a broadcast program or the like by an operation from the user, it notifies the application A1 of the receiving device 30 of the instruction regarding the viewing. In the receiving device 30, the application A1 transmits a license request to the license server 50 via the network 90 in accordance with the viewing instruction from the application A2 (S115).

[0095] The license server 50 generates a license in response to the request from the receiving device 30 and transmits it to the receiving device 30 via the network 90 (S116). The encrypted part of the license has information such as a license key and an expiration date, and is encrypted with the master key (Km).

[0096] The receiving device 30 receives the license transmitted from the license server 50 and transmits (transfers) it to the second screen terminal device 40 (S116). The license transmitted from the receiving device 30 is received by the second screen terminal device 40 and held by the CAS platform P2 (S117). The CAS platform P2 can obtain information such as the license key and the expiration date arranged therein by decrypting the encrypted part of the license using the master key (Km) held in advance.

[0097] In this way, in the device connection phase (S101), secure communication is performed between the receiving device 30 and the second screen terminal device 40, and the license from the license server 50 is retained.

[0098] In the broadcast program viewing phase (S102), processing for viewing broadcast content is performed. In the broadcast program viewing phase (S102), since steps S121 to S124 are the same as steps S21 to S24 in the broadcast program viewing phase (S2) of FIG. 4, the description thereof is omitted.

[0099] Next, in the communication program viewing phase (S103), the stream server 20 transmits an ECM as a common message via the network 90 in response to a viewing request from the second screen terminal device 40 (S131, S132). The ECM transmitted from the stream server 20 is received by the second screen terminal device 40.

[0100] In the second screen terminal device 40, the application A2 acquires the received ECM and injects (inputs) it into the CAS platform P2 (S133).

[0101] The CAS platform P2 decrypts the encrypted part of the ECM injected from the application A2 using the working key (Kw) retained in the device connection phase (S101), and performs a determination process of comparing the reference license key arranged therein with the license key of the license retained in the device connection phase (S101). In this determination process, when the current time of the ECM is within the validity period of the license and the reference license key and the license key match, the scramble key (Ks) is read from the encrypted part of the ECM. The CAS platform P2 notifies the application A2 of the scramble key (Ks) (S134).

[0102] The stream server 20 transmits the AV stream of the communication content to the second screen terminal device 40 via the network 90 (S135). The AV stream transmitted from the stream server 20 is received by the second screen terminal device 40.

[0103] In the second screen terminal device 40, the application A2 decrypts the encrypted data included in the AV stream using the scrambling key (Ks) from the CAS platform P2. In the second screen terminal device 40, the audio data and video data are decoded, and the audio and video of the communication content are output. Thereby, the user can view communication content such as a broadcast program.

[0104] In this way, in the communication program viewing phase (S103), when the user views the communication content, the encrypted data of the AV stream distributed via the communication transmission path is decrypted. In this decryption, the scrambling key (Ks) obtained by decrypting the encrypted part of the ECM distributed via the communication transmission path based on the work key (Kw) and the license held in the device connection phase (S101) is used.

[0105] In the sequence of FIG. 7, the case where the determination process using the license is performed in the communication program viewing phase (S103) is illustrated, but the determination process using the license may be performed in the broadcast program viewing phase (S102). Also, in the sequence of FIG. 7, the case where the receiving device 30 transfers the license from the license server 50 to the second screen terminal device 40 is illustrated, but the second screen terminal device 40 may directly receive the license transmitted from the license server 50 via the network 90.

[0106] As described above, in the present technology, since the receiving device can perform determination processing using the license distributed from the license server 50, for example, when distributing a paid broadcast program such as PPV as encrypted content, it is possible to easily determine whether the receiving device is a viewable device.

[0107] <3. Third Embodiment>

[0108] (System Configuration) FIG. 8 shows a third example of the configuration of the content distribution system to which the present technology is applied.

[0109] In FIG. 8, compared with the configuration shown in FIG. 1, as the receiving device, the second screen terminal device 40 is removed, and only the receiving device 30 is provided. In the configuration shown in FIG. 8, the parts corresponding to those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0110] In FIG. 8, the receiving device 30 is a device such as a television receiver, a smartphone, or a tablet terminal having functions corresponding to a predetermined broadcast method and a predetermined communication method. The receiving device 30 receives and processes the broadcast signal transmitted from the broadcast transmission device 10 via the broadcast transmission path, and makes the broadcast content viewable. Further, the receiving device 30 receives and processes the data transmitted from the stream server 20 via the network 90, and makes the communication content viewable.

[0111] FIG. 9 shows an example of the detailed configuration of the receiving device 30 in FIG. 8. In the configuration shown in FIG. 9, the parts corresponding to those shown in FIG. 3 are denoted by the same reference numerals. That is, the receiving device 30 in FIG. 9 is provided with a work key holding unit 311, a communication unit 312, a decoding unit 313, and a decoder 314 in addition to the control unit 300 to the output unit 306 compared with the receiving device 30 in FIG. 3.

[0112] The work key holding unit 311 stores and holds the work key (Kw) supplied from the CAS system 304. The communication unit 312 receives the ECM transmitted from the stream server 20 and supplies it to the work key holding unit 311. The work key holding unit 311 decrypts the encrypted part of the ECM from the communication unit 312 using the held work key (Kw), and supplies the resulting scramble key (Ks) to the decoding unit 313.

[0113] The communication unit 312 supplies the AV stream transmitted from the stream server 20 to the decoding unit 313. The decoding unit 313 decrypts the encrypted data of the AV stream supplied from the communication unit 312 using the scramble key (Ks) from the work key holding unit 311, and supplies the resulting audio data and video data to the decoder 314.

[0114] The decoder 314 has an audio decoder and a video decoder compliant with a predetermined decoding method. The decoder 314 decodes the audio data supplied from the decoding unit 313 and supplies it to the output unit 306. The decoder 314 decodes the video data supplied from the decoding unit 313 and supplies it to the output unit 306.

[0115] Note that the configuration of the receiving device 30 shown in FIG. 9 is an example, and other components may be added or some of the components may be deleted. For example, in the receiving device 30 shown in FIG. 9, the decoder 305 and the decoder 314 are configured separately, but they may be configured as one decoder.

[0116] (Sequence flow) FIG. 10 shows a third example of a sequence representing the interaction between the devices constituting the content distribution system of FIG. 8 in chronological order.

[0117] In FIG. 10, the flow of data exchanged between the transmitting devices consisting of the broadcast transmission device 10 and the stream server 20 and the receiving device 30 consisting of the receiving device 30 is shown. In the receiving device 30, the application A1 and the CAS platform P1 are operating.

[0118] After the pre-view phase (S201) that is performed before viewing the program, similar to the sequence of FIG. 4, a broadcast program viewing phase (S202) and a communication program viewing phase (S203) are performed in the sequence of FIG. 10.

[0119] In the pre-view phase (S201), the application A1 holds a working key (Kw) obtained by decrypting the encrypted part of the EMM transmitted from the broadcast transmission device 10 with the device key (Kd) (S211, S212).

[0120] Next, in the broadcast program viewing phase (S202), the application A1 of the receiving device 30 injects the ECM transmitted from the broadcast transmission device 10 into the CAS platform P1 (S221, S222). The CAS platform P1 of the receiving device 30 notifies the application A1 of a scrambling key (Ks) obtained by decrypting the encrypted part of the ECM using the working key (Kw) held in the pre-view phase (S201) (S223).

[0121] In the receiving device 30, the application A1 decrypts the encrypted data included in the AV stream transmitted from the broadcast transmission device 10 using the scrambling key (Ks) from the CAS platform P1 (S224). In the receiving device 30, the decrypted audio data and video data are decoded, and the audio and video of the broadcast content are output. Thereby, the user can view broadcast content such as a broadcast program.

[0122] Next, in the communication program viewing phase (S203), the application A1 of the receiving device 30 injects the ECM as a common message transmitted from the stream server 20 into the CAS platform P1 (S231 to S233). The CAS platform P1 of the receiving device 30 notifies the application A1 of a scrambling key (Ks) obtained by decrypting the encrypted part of the ECM using the working key (Kw) held in the pre-view phase (S201) (S234).

[0123] In the receiving device 30, the application A1 decrypts the encrypted data included in the AV stream transmitted from the stream server 20 by using the scramble key (Ks) from the CAS platform P1 (S235). In the receiving device 30, the decrypted audio data and video data are decoded, and the audio and video of the communication content are output. Thereby, the user can view communication content such as a broadcast program.

[0124] As described above, in this technology, in the receiving device 30 having functions corresponding to a predetermined broadcast system and a predetermined communication system, by holding the working key (Kw) of the CAS system 304, the scramble key (Ks) obtained by using the working key (Kw) is used to decrypt the encrypted content distributed via the communication transmission path, making it possible to view communication content such as a broadcast program. Thereby, it is possible to more easily make the encrypted content viewable without implementing a dedicated CAS system or a dedicated signal processing circuit such as a descrambler for making the encrypted content distributed via the communication transmission path viewable.

[0125] <4. Modification Example>

[0126] In the above description, as a mechanism for protecting content, a conditional access system (CAS) is described as an example. However, any other system for encrypting and protecting content may be adopted. In the above description, as a path through which encrypted content is distributed, a broadcast transmission path and a communication transmission path are described as an example. However, any other combination of different paths may be adopted. Also, even when both use the broadcast system (or communication system), if the paths for distributing the encrypted content are different, the present technology can be applied.

[0127] In the configuration shown in FIGS. 1 and 5 described above, the case where one second screen terminal device 40 is provided for one receiving device 30 has been exemplified, but a plurality of second screen terminal devices 40 may be provided. At this time, in the second and subsequent second screen terminal devices 40, the same processing as that of the first second screen terminal device 40 is performed.

[0128] The second encrypted content (communication content) decrypted by the second screen terminal device 40 used as the second screen terminal of the receiving device 30 such as a television receiver can be the same program as the first encrypted content (broadcast content) decrypted by the receiving device 30 or related programs (programs produced by the same or different broadcasting stations, etc.). Further, the second encrypted content (communication content) may be information related to the first encrypted content (broadcast content) (including information such as images and texts).

[0129] <5. Configuration of Computer>

[0130] The series of processes described above can be executed by hardware or by software. When the series of processes are executed by software, the program constituting the software is installed in a computer.

[0131] FIG. 11 shows an example of the hardware configuration of a computer that executes the series of processes described above by a program.

[0132] In a computer, a CPU (Central Processing Unit) 1001, a ROM (Read Only Memory) 1002, and a RAM (Random Access Memory) 1003 are interconnected by a bus 1004. An input / output interface 1005 is further connected to the bus 1004. An input unit 1006, an output unit 1007, a storage unit 1008, a communication unit 1009, and a drive 1010 are connected to the input / output interface 1005.

[0133] The input unit 1006 consists of a keyboard, a mouse, a microphone, etc. The output unit 1007 consists of a display, a speaker, etc. The storage unit 1008 consists of a hard disk, a non-volatile memory, etc. The communication unit 1009 consists of a network interface, etc. The drive 1010 drives a removable storage medium 1011 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory.

[0134] In the computer configured as described above, the CPU 1001 loads and executes the programs recorded in the ROM 1002 and the storage unit 1008 via the input / output interface 1005 and the bus 1004 into the RAM 1003, whereby the above-described series of processes are performed.

[0135] The program executed by the computer (CPU 1001) can be recorded and provided, for example, on a removable storage medium 1011 as a package medium or the like. Also, the program can be provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital satellite broadcasting.

[0136] In the computer, the program can be installed in the storage unit 1008 via the input / output interface 1005 by mounting the removable storage medium 1011 on the drive 1010. Also, the program can be received by the communication unit 1009 via a wired or wireless transmission medium and installed in the storage unit 1008. Additionally, the program can be installed in advance in the ROM 1002 and the storage unit 1008.

[0137] In this specification, the processing performed by a computer according to a program does not necessarily need to be performed in chronological order along the order described as a flowchart. That is, the processing performed by a computer according to a program includes processing that is executed in parallel or individually (for example, parallel processing or object-based processing). Further, the program may be processed by one computer (processor) or may be distributedly processed by a plurality of computers. Furthermore, the program may be transferred to a remote computer and executed.

[0138] In this specification, a system means a collection of a plurality of components (devices, modules (parts), etc.), and it does not matter whether all the components are in the same housing. Therefore, a plurality of devices housed in separate housings and connected via a network, and one device in which a plurality of modules are housed in one housing are both systems.

[0139] Note that the embodiments of the present technology are not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present technology. For example, the present technology can take a configuration of cloud computing in which one function is shared and jointly processed by a plurality of devices via a network.

[0140] The effects described in this specification are merely illustrative and not restrictive, and there may be other effects.

[0141] Note that the present technology can take the following configuration.

[0142] (1) a receiving unit that receives first encrypted content distributed via a first transmission path; a first decryption unit that decrypts the first encrypted content using a first key included in a first message distributed via the first transmission path; a control unit that controls the operations of each unit and The first message is encrypted with a second key included in a second message distributed via the first transmission path. The control unit controls so that the second key is provided to a second decryption unit that decrypts second encrypted content distributed via a second transmission path. Receiving device. (2) The second decryption unit is provided in a terminal device. The terminal device further includes a communication unit that exchanges data with the terminal device. The communication unit transmits the second key to the terminal device. The receiving device according to (1) above. (3) The first encrypted content and the second encrypted content are encrypted with the same or different first keys. The receiving device according to (1) or (2) above. (4) The second message is encrypted with a third key. The control unit acquires the second key obtained by decrypting the second message using the third key. The receiving device according to any one of (1) to (3) above. (5) The receiving unit receives the second message via the first transmission path. The control unit controls so that the second key obtained by decrypting the received second message using the third key is held in the holding unit and provided to the second decryption unit. The receiving device according to (4) above. (6) The receiving unit receives the first message via the first transmission path. The first decryption unit decrypts the first encrypted content using the first key obtained by decrypting the received first message using the held second key. The receiving device according to (5) above. (7) The control unit controls so as to provide the license distributed via the second transmission path to the terminal device. The receiving device according to (2) above. (8) When communicating with the terminal device, the communication unit exchanges encrypted data. The receiving device according to (2) or (7) above. (9) Further comprising the second decoding unit The receiving device according to (1) above. (10) The first transmission path is a broadcast transmission path, The second transmission path is a communication transmission path, The first message is a common message, The second message is an individual message, The first key is a scramble key, The second key is a work key The receiving device according to any one of (1) to (9) above. (11) The first encrypted content and the second encrypted content are the same or related programs. The receiving device according to any one of (1) to (10) above. (12) The receiving device Decodes the first encrypted content distributed via the first transmission path using the first key included in the first message distributed via the first transmission path, Controls so that the second key included in the second message distributed via the first transmission path is provided to the second decoding unit that decodes the second encrypted content distributed via the second transmission path, The first message is encrypted with the second key Control method. (13) A holding unit that holds the second key provided from a receiving device having a first decoding unit that decodes the first encrypted content distributed via the first transmission path, A receiving unit that receives second encrypted content distributed via a second transmission path, A second decryption unit that decrypts the second encrypted content using a first key included in a first message distributed via the second transmission path and comprises The first message is encrypted with the second key, The first key is obtained by decrypting the first message using the second key held in the holding unit Terminal device. (14) The first encrypted content and the second encrypted content are encrypted with the same or different first keys The terminal device according to (13) above. (15) The receiving unit receives the first message via the second transmission path, The second decryption unit decrypts the second encrypted content using the first key obtained by decrypting the received first message using the second key held The terminal device according to (13) or (14) above. (16) The holding unit holds a license provided from the receiving device, The second decryption unit decrypts the second encrypted content using the first key obtained according to the determination process using the first message and the license The terminal device according to (15) above. (17) Further comprising a communication unit for data exchange with the receiving device, The communication unit receives the second key transmitted from the receiving device, The holding unit holds the received second key The terminal device according to any one of (13) to (16) above. (18) The first transmission path is a broadcast transmission path, The second transmission path is a communication transmission path, The first message is a common message, The first key is a scramble key, The second key is a work key The terminal device according to any one of (13) to (17). (19) The first encrypted content and the second encrypted content are the same or related programs The terminal device according to any one of (13) to (18). (20) A terminal device holds a second key provided from a receiving device having a first decryption unit that decrypts first encrypted content distributed via a first transmission path, uses the first key included in the first message distributed via the second transmission path to decrypt the second encrypted content distributed via the second transmission path, The first message is encrypted with the second key, By decrypting the first message using the held second key, the first key is obtained Control method. (21) A generation unit that generates a first message including a first key for decrypting second encrypted content distributed via a second transmission path, a transmission unit that transmits the first message via the second transmission path and includes The first message is encrypted with the same second key as the first message including the first key for decrypting the first encrypted content distributed via the first transmission path Transmission device. (22) The first encrypted content and the second encrypted content are encrypted with the same or different first keys The transmission device according to (21). (23) The first transmission path is a broadcast transmission path or a communication transmission path, The second transmission path is a communication transmission path or a broadcast transmission path, The first message is a common message, The first key is a scrambling key, The second key is a work key The transmission device according to (21) or (22). (24) The first encrypted content and the second encrypted content are the same or related programs The transmission device according to any one of (21) to (23). (25) The transmission device generates a first message including a first key for decrypting second encrypted content distributed via a second transmission path, transmits the first message via the second transmission path, the first message is encrypted with the same second key as the first key included in the first encrypted content distributed via the first transmission path Transmission method.

Explanation of symbols

[0143] 10 Broadcast transmission device, 20 Stream server, 30 Receiver, 40 Second screen terminal device, 50 License server, 90 Network, 300 Control unit, 301 Tuner, 302 Descrambler, 303 Demultiplexer, 304 CAS system, 305 Decoder, 306 Output unit, 307 Communication unit, 311 Work key holding unit, 312 Communication unit, 313 Decryption unit, 314 Decoder, 400 Control unit, 401 Communication unit, 402 Work key holding unit, 403 Communication unit, 404 Decryption unit, 405 Decoder, 406 Output unit, 1001 CPU

Claims

1. A receiving unit that receives first encrypted content distributed via a first transmission path; A first decryption unit that decrypts the first encrypted content using a first key included in a first message distributed via the first transmission path; A control unit that controls the operations of each unit and comprising: The first message is encrypted with a second key included in a second message distributed via the first transmission path, The control unit controls so that the second key is provided to a second decryption unit that decrypts second encrypted content distributed via a second transmission path Receiving device.

2. The second decryption unit is provided in a terminal device, The receiving device further includes a communication unit that exchanges data with the terminal device, The communication unit transmits the second key to the terminal device The receiving device according to claim 1.

3. The first encrypted content and the second encrypted content are encrypted with the same or different first keys The receiving device according to claim 1.

4. The second message is encrypted with a third key, The control unit acquires the second key obtained by decrypting the second message using the third key The receiving device according to claim 1.

5. The receiving unit receives the second message via the first transmission path, The control unit controls such that the second key obtained by decrypting the received second message using the third key is held in a holding unit and provided to the second decryption unit The receiving device according to claim 4.

6. The receiving unit receives the first message via the first transmission path, The first decryption unit decrypts the first encrypted content using the first key obtained by decrypting the received first message using the held second key The receiving device according to claim 5.

7. The control unit controls so that a license distributed via the second transmission path is provided to the terminal device The receiving device according to claim 2.

8. When communicating with the terminal device, the communication unit exchanges encrypted data The receiving device according to claim 2.

9. Further comprising the second decryption unit The receiving device according to claim 1.

10. The first transmission path is a broadcast transmission path, The second transmission path is a communication transmission path, The first message is a common message, The second message is an individual message, The first key is a scrambling key, The second key is a work key The receiving device according to claim 1.

11. A receiving device, using a first key included in a first message distributed via a first transmission path, decrypts first encrypted content distributed via the first transmission path, controls to provide a second key included in a second message distributed via the first transmission path to a second decryption unit that decrypts second encrypted content distributed via a second transmission path, The first message is encrypted with the second key Control method.

12. A holding unit that holds a second key provided from a receiving device having a first decryption unit that decrypts first encrypted content distributed via a first transmission path; A receiving unit that receives second encrypted content distributed via a second transmission path; A second decryption unit that decrypts the second encrypted content using a first key included in a first message distributed via the second transmission path comprising: The first message is encrypted with the second key, The first key is obtained by decrypting the first message using the second key held by the holding unit Terminal device.

13. The first encrypted content and the second encrypted content are encrypted with the same or different first keys The terminal device according to claim 12.

14. The receiving unit receives the first message via the second transmission path, The second decryption unit decrypts the second encrypted content using the first key obtained by decrypting the received first message using the second key held The terminal device according to claim 12.

15. The holding unit holds a license provided from the receiving device, The second decryption unit decrypts the second encrypted content using the first key obtained according to a determination process using the first message and the license The terminal device according to claim 14.

16. further comprising a communication unit that exchanges data with the receiving device, The communication unit receives the second key transmitted from the receiving device, The holding unit holds the received second key The terminal device according to claim 12.

17. The first transmission path is a broadcast transmission path, The second transmission path is a communication transmission path, The first message is a common message, The first key is a scramble key, The second key is a work key The terminal device according to claim 12.

18. A terminal device, holds a second key provided from a receiving device having a first decoding unit that decodes first encrypted content distributed via a first transmission path, uses a first key included in a first message distributed via a second transmission path to decode second encrypted content distributed via the second transmission path, the first message is encrypted with the second key, the first key is obtained by decrypting the first message with the held second key Control method.

19. A generation unit that generates a first message including a first key for decrypting second encrypted content distributed via a second transmission path, a transmission unit that transmits the first message via the second transmission path and is provided with, the first message is encrypted with the same second key as the first message including the first key for decrypting the first encrypted content distributed via the first transmission path Transmission device.

20. The first encrypted content and the second encrypted content are encrypted with the same or different first keys The transmission device according to claim 19.

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