KR20060111823A - Entitlement management message transmitting system and method thereof in use of out of band - Google Patents

Abstract

An EMM(Entitlement Management Message) transmitting system using an OOB(Out Of Band) channel and a method thereof are provided to perform bi-directional communication with a CAS(Conditional Access System) client by transmitting an EMM in real time and feedback information about success/failure/error with respect to the transmission of the EMM. In an EMM transmitting system using an OOB, a CAS server(210) transmits an EMM related to an entitlement of a CAS client(230) through an OOB channel(240), and transmits an ECM(Entitlement Control Message) related to a key allotted to the CAS client(230) through an IB(In Band) channel. A broadcasting stream encryption device(220) encrypts the ECM generated in the CAS server(210), modulates the ECM to be suitable for the transmission through the IB channel, and transmits the ECM to the IB channel.

Description

EMM transmission system and method using the out-of-band channel {ENTITLEMENT MANAGEMENT MESSAGE TRANSMITTING SYSTEM AND METHOD THEREOF IN USE OF OUT OF BAND}

1 is a view showing the configuration of an EMM transmission system according to the prior art.

2 illustrates an EMM transmission system using an out-of-band channel according to the present invention.

Figure 3 is a block diagram showing the configuration of a CAS server according to the present invention.

4 is a block diagram showing a broadcast stream encoding apparatus according to the present invention.

5 is a flowchart illustrating an EMM transmission method using an out-of-band channel according to the present invention.

6 is a diagram showing an EMM transmission system using a mobile communication network according to a first embodiment of the present invention.

7 illustrates a header of an EMM transmitted from a CAS server to an I / F server according to the first embodiment of the present invention.

8 illustrates a header of an EMM transmitted from an I / F server to an OTA server according to the first embodiment of the present invention.

9 illustrates an EMM transmission system using an IP-based network according to a second embodiment of the present invention.

10 is a block diagram showing an IP-based network according to a second embodiment of the present invention.

11 is a diagram showing a header of an EMM transmitted from a CAS server to an IP packet routing server according to a second embodiment of the present invention.

* Explanation of Codes on Major Parts of Drawings *

210: CAS server 220: broadcast stream encoding apparatus

230: CAS client 240: OOB channel

250: mobile communication network 260: IP based network

The present invention relates to a CAS (Conditional Access System), and more particularly, to an EMM transmission system and method using an out-of-band channel.

As communication and digital technologies have advanced dramatically, digital broadcasting technologies have been developed and commercialized. In the conventional analog broadcasting, only one piece of information can be loaded on one radio wave, and thus, when there is video information and audio information, the corresponding information has to be transmitted through different radio waves. In addition, in analog broadcasting, only a broadcast provider can receive information unilaterally sent, but the viewer cannot send information to the broadcast provider. On the contrary, since digital broadcasting provides broadcast information in a digital form, a plurality of video or audio information can be loaded in one radio wave, and the information can be compressed without degrading broadcast quality. In addition, it is easy to control information using a computer, and bi-directionally enables the viewer to send information to a broadcast provider.

Digital broadcasting is a core technology of the multimedia age combining broadcasting, communication, and computers. Recently, digital broadcasting is rapidly being digitalized not only in satellite broadcasting and cable television but also in conventional terrestrial broadcasting. The core of such digital broadcasting lies in the above-mentioned bidirectionality and the pay broadcasting service based on the above-mentioned bidirectionality. Pay broadcasting service is the most important function as a profit model of the digital broadcasting service provider, thereby providing an environment in which various types of services can be provided by not only the broadcasting service provider but also individual content providers. In order to implement a pay broadcasting service, it is necessary to use a conditional access system (CAS) in which only authorized subscribers can use digital broadcasting.

CAS encrypts broadcast content and sends it to the receiving terminal via cable, satellite, terrestrial and Internet, etc., and the content is sent if the receiver has the right to use the content (that is, paid for the content). It is a technology that enables a paid broadcast service by decoding and using. The CAS transmits an Entitlement Management Message (EMM) used for subscriber authentication to limit the reception of the viewer to the receiving terminal, and the receiving terminal uses the information included in the EMM to watch the digital broadcasting content received through subscriber authentication. .

Hereinafter, this will be described in more detail with reference to the accompanying drawings.

1 is a view showing the configuration of an EMM transmission system according to the prior art.

As shown in FIG. 1, a CAS that generates an EMM associated with a subscriber viewing qualification and a rating for a pay channel at predetermined intervals, and transmits the EMM to a CAS client to be described later through the broadcast stream encoding apparatus 120 and a broadcasting network. (Conditional Access System) server 110; And a CAS client 130 for receiving the broadcast signal and the EMM transmitted through the broadcast stream encoding apparatus 120 and the broadcast network, and interpreting the EMM to display only the broadcast signal corresponding to a rating.

Here, the CAS client 130 includes a smart card (not shown) for storing subscriber information in advance and setting and changing a rating by receiving an EMM.

The EMM transmission method according to the prior art configured as described above will be described.

First, the CAS server 110 generates an EMM including a smart card number and its changes and broadcasts it to all the CAS clients 130 through the broadcast stream encoding apparatus 120 and the broadcast network. That is, the CAS server 110 manages the user's viewing qualifications, viewing ratings for paid channels, etc. through the EMM. At this time, the EMM is a message (EMM) associated with the information on the channel viewing eligibility of the user of the CAS client 130 and the ratings of the paid channel (EMM) and a message related to the key information that can decode the scramble of the paid channel Entitlement Control Message (ECM). In this case, the EMM may include key information for decrypting the scramble of the pay channel.

Therefore, after receiving the EMM transmitted from the broadcasting network, the CAS client 130 parses the ECM and matches the key information of the embedded smart card until it matches the viewing qualification and the paid channel through the EMM. The ratings are managed.

However, since the EMM is sent to all CAS clients approximately once every one to thirty minutes, when a CAS client belonging to a shaded area fails to receive the EMM, the EMM is timely given a changed viewing qualification and a rating for the paid channel. There was a problem.

An object of the present invention is to provide an EMM transmission system and method using an out-of-band channel that can transmit an Entitlement Management Message (EMM) of a pay broadcasting service through a secondary channel, rather than through a broadcast channel.

In order to achieve the above object, the EMM transmission system using the out-of-band channel according to the present invention, the Entitlement Management Message (EMM) associated with the Entitlement (Entitlement) of the CAS (Conditional Access System) client OOB (Out of Band) channel A CAS (Conditional Access System) server for transmitting an Entitlement Control Message (ECM) associated with a key assigned to each CAS client through an in-band channel; And a broadcast stream encoding apparatus for encrypting the ECM generated by the CAS server, modulating the ECM appropriately for transmission through the IB channel, and then transmitting the IB channel.

Here, the OOB channel is characterized in that the mobile communication network.

In addition, the OOB channel is characterized in that the IP-based network.

On the other hand, the EMM transmission method for the out-of-band channel according to the present invention, a) CAS (Conditional Access System) server generates an Entitlement Management Message (EMM) through the subscriber key and the viewing credentials message, encrypts it to OOB (Out) transmitting to a CAS client through a channel of Band); b) After the CAS server encodes the subscriber key and the control word (CW), the CAS server generates an Entitlement Control Message (ECM) based on the encoded subscriber key and the CW, and encrypts the generated ECM through an encoder to perform the broadcast. Transmitting to a stream encoding apparatus; And c) synchronizing the encrypted ECM with the CW, and transmitting the scrabble A / V stream to the CAS client through an IB channel based on the encrypted ECM and CW. It is done.

Here, the OOB channel is characterized in that the mobile communication network.

In addition, the OOB channel is characterized in that the IP-based network.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and preferred embodiments. Like reference numerals refer to like or similar elements throughout the drawings.

2 is a diagram illustrating an EMM transmission system using an out-of-band channel according to the present invention.

As shown in FIG. 2, the system includes a CAS (Conditional Access System) server 210, a broadcast stream encoding apparatus 220, an in-band (IB) channel, an out-of-band (OBB) channel ( 240) and CAS client (230).

The CAS server 210 transmits the EMM related to the entitlement of the CAS client 230 through the OOB channel 240, and sends the ECM related to the key assigned to each CAS client 230 through the IB channel. send.

The IB channel is a channel for scrambled A / V stream and ECM to be transmitted in a broadcasting center (not shown) and transmitted in MPEG2 TS (Transport Stream) type. For example, broadcast channels such as satellite broadcast channels, terrestrial broadcast channels, and the like can be given.

The OOB channel 240 means a secondary channel other than the IB channel, and the EMM generated by the CAS server 210 is transmitted. For example, a mobile communication network or an IP-based network may be mentioned. By transmitting the EMM through the OOB channel 240 as described above, it is possible to reduce the waste of bandwidth and transmit the EMM to each client in real time, compared to the conventional method of transmitting the EMM, ECM, and A / V streams all through the IB channel. Can be.

The broadcast stream encoding apparatus 220 synchronizes the ECM generated by the CAS server 210, modulates it for transmission through the IB channel, and transmits the same through the IB channel. Preferably, the data is transmitted in the MPEG2 TS type.

The CAS client 230 receives a key related to authentication from the CAS server 210 and is authenticated to use the broadcast channel to receive the corresponding broadcast channel. That is, the CAS client 230 receives the EMM from the CAS server 210 through the OOB channel 240, and then through the EMM, the CAS client 230 decodes the CW included in the ECM and decrypts the decrypted CW. The scrambled A / V stream is descrambled to display a corresponding broadcast channel. The CAS client 230 includes a personal digital assistant (PDA), a hand-held PC, a code division multiple access (CDMA) phone, a global system for mobile (GSM) phone, a wideband CDMA (WCDMA) phone, and an MBS. (Mobile Broadband System) It consists of a terminal such as a phone.

3 is a block diagram showing the configuration of a CAS server according to the present invention.

As shown in FIG. 3, the CAS server 210 includes a key generator 211, a viewer qualification generator 216, an encoder 212, an ECM generator 213, an encoder 214, and an EMM generator 215. It includes.

The key generator 211 generates a key used to encrypt the CW and used by the CAS client 230 to decrypt the CW.

The entitlement generator 216 generates an entitlement message (eg, in the case of a new subscription or a change of service) that records each viewing entitlement for a specific broadcast channel transmitted to the CAS client 230, and the CAS. When key authentication is performed in the client 230, only the viewable broadcast channel recorded in the viewing qualification message is displayed.

The encoder 212 receives the CW used to scramble the A / V stream from the broadcast stream encoder 220 and encrypts the CW.

The ECM generator 213 receives the ID of the key and the serial number of the key from the key generator 211, which will be described later, receives the encrypted CW from the encoder 214, and generates an ECM to broadcast stream encoding apparatus 220. To pass.

The encryptor 214 encrypts the ECM and EMM so that information of the ECM and EMM is not exposed to the outside during transmission.

The EMM generator 215 receives the key from the key generator 211 and receives the viewing qualification message from the viewer qualification generator 216 to generate the EMM. In this case, the EMM includes information on a broadcast channel allowed for subscriber authentication and use of the CAS client 230.

4 is a block diagram showing a broadcast stream encoding apparatus according to the present invention.

As shown in FIG. 4, the broadcast stream encoding apparatus 220 includes a CW generator 221, a synchronizer 222, and a scrambler 223.

The CW generator 221 generates a control word (CW) to scramble the A / V stream provided to the CAS client 230, and the CW is randomly generated and periodically changed.

The synchronizer 222 synchronizes the ECM transmitted from the CAS server 210 and the CW generated by the CW generator 221.

The scrambler 223 scrambles the A / V stream which is a broadcast stream through CW. Scramble is a process of encrypting a bit string of an A / V stream, in order to prevent unauthorized users from playing the A / V stream.

An EMM transmission method using an out-of-band channel according to the present invention configured as described above will be described with reference to FIG. 5.

First, the CAS server 210 includes subscriber keys assigned for each CAS client 230 to identify the CAS client 230, and each CAS client 230 includes its own subscriber key. Accordingly, the CAS server 210 generates an EMM through the subscriber key and the viewing credentials message assigned to the CAS client 230, encrypts the EMM, and converts the encrypted EMM through the OOB channel 240 to the CAS client 230. (S501).

On the other hand, CAS server 210 encodes the subscriber key and CW and transmits to the ECM generator (213). Subsequently, an ECM is generated based on the encoded subscriber key and CW, and the generated ECM is encrypted by the encoder 214 and transmitted to the broadcast stream encoding apparatus 220 (S502).

Meanwhile, the CW generated by the C / W generator is transmitted to the synchronizer 222, and the synchronizer 222 transmits the encrypted ECM to the scrambler 223 by synchronizing the CW with the scrambler 223. After scrambled the encrypted ECM and A / V stream based on CW, it transmits to the CAS client 230 in the form of MPEG2 TS through the IB channel (S503).

Meanwhile, the CAS client 230 receiving the EMM through the OOB channel 240 decrypts the EMM through a key stored in a smart card (not shown) to confirm the viewer's qualification and key ID. Subsequently, the encrypted ECM and the scrambled A / V stream are received through the IB channel to check whether the key ID included in the encrypted ECM matches the key ID decrypted through the EMM.

If the above-described key ID matches, the CAS client 230 decrypts the CW included in the ECM using the key ID. Subsequently, the scrambled A / V stream is descrambled using the CW to display a broadcast channel corresponding to the viewing qualification.

Hereinafter, specific examples of an EMM transmission system using an out-of-band channel according to the present invention will be described with reference to the accompanying drawings.

(First embodiment)

6 is a diagram showing the configuration of an EMM transmission system using a mobile communication network according to a first embodiment of the present invention. Here, the encrypted EMM is transmitted through the mobile communication network 250 instead of the IB channel. Accordingly, since the mobile communication network 250 is the same, detailed description thereof will be omitted.

As shown in FIG. 6, the mobile communication network 250 includes an I / F (Interface) server and an OTA server 252.

The CAS server 210 adds a header as shown in FIG. 7 to transmit the EMM through the mobile communication network 250. The header includes identifier information (Message id) indicating that the EMM, CAS client 230 information (Client id) to be transmitted, mobile carrier information (Teleco id) where the OTA server 252 is located, and the movement of the CAS client 230. Contains a telephone number (Teleco No).

The I / F server 251 serves as a message interpretation server between the CAS server 210 and the OTA server 252 of the mobile communication network 250, and provides information that can be managed by classifying sessions for each mobile carrier. Included, and repackaged in a format that can be received by the OTA server 252 and transmitted to the OTA server 252 of each mobile communication company.

In addition, the I / F server 251 includes a separate management module (not shown) for success / failure / error information for EMM transmission from the OTA server 252 to each CAS client 230. The CAS server 210 receives the feedback of the success / failure / error of the EMM transmission through the Callback URL of the SMS transmitted to the CAS client 230 and transmits the feedback to the CAS server 210 using the management module. Is the basis for the decision on whether to retransmit the EMM.

Accordingly, the I / F server 251 receives the EMM with the header added from the CAS server 210, and transmits the EMM to the OTA server 252 in the form as shown in FIG.

The OTA server 252 is a server built for each mobile communication company, and processes the EMM into various types of messages such as SMS and transmits the same to the CAS client 230.

Second Embodiment

9 is a diagram illustrating a configuration of an EMM transmission system using an IP-based network according to a second embodiment of the present invention. Here, the encrypted EMM is transmitted through the IP-based network 260 instead of the IB channel. Accordingly, since the IP-based network 260 is the same, detailed description thereof will be omitted.

10 is a diagram illustrating a configuration of an IP based network according to a second embodiment of the present invention.

As shown in FIG. 10, the IP-based network 260 includes an IP packet routing server 261, a listening server 262 and other IP-based network equipment.

The IP packet routing server 261 performs the function of delivering the EMM from the CAS server 210 to the CAS client 230, and the listening server 262 has a form such as a web server and the CAS client 230. The request message for the CAS server 210 is received and processed.

For example, when there is no key information or viewing qualification information necessary for a program and / or a package that a subscriber can watch, the subscriber is transmitted to the CAS server 210 through the listening server 262 and retransmitted.

In this case, in order to transmit the EMM through the IP-based network 260, a header as shown in FIG. 11 must be added to the EMM. The header must include source IP address information and destination IP address information.

While the present invention has been described in detail with reference to preferred embodiments, those skilled in the art will recognize that various modifications or changes can be made without departing from the spirit and scope of the invention.

As described above, according to the present invention, by using the out-of-band channel, the bandwidth of the IB channel can be reduced, and the EMM can be transmitted in real time.

In addition, according to the present invention, by using the out-of-band channel to transmit the EMM in real time and feedback the information on the success / failure / error for the EMM transmission there is an effect that can perform bidirectional communication for the CAS client.

Claims (22)

An Entitlement Management Message (EMM) related to Entitlement of a Conditional Access System (CAS) client is transmitted through an Out of Band (OOB) channel, and an Entitlement Control Message (ECM) related to a key assigned to each CAS client. A CAS (Conditional Access System) server to transmit through an in-band channel; And EMB transmission system using an out-of-band channel characterized in that it comprises a broadcast stream encoding apparatus for encrypting the ECM generated by the CAS server, and then modulated to transmit on the IB channel, and then transmitted to the IB channel. The method of claim 1, wherein the CAS client, After receiving the EMM from the CAS server through the OOB channel, the CW (Control Word) included in the ECM is decoded through the EMM, and the corresponding scrambled A / V stream is descrambled using the decoded CW to broadcast the broadcast. EMM transmission system using an out-of-band channel, characterized in that for displaying the channel. The method of claim 1 or 2, wherein the CAS server, A key generator for generating a key used for encrypting and decrypting CW (Control Word); An entitlement generator (Entitlement) generator for generating a view entitlement message recording each view entitlement for a specific broadcast channel transmitted to the CAS client; An encoder which receives the CW and encodes the CW; An ECM generator for generating an ECM by receiving a key from the key generator and receiving the encoded CW; An EMM generator for generating the EMM by receiving the key from the key generator and receiving a viewer qualification message from the viewer qualification generator; And EMM transmission system using an out-of-band channel, characterized in that for encrypting the ECM and EMM so that the information of the ECM and EMM is not exposed to the outside during transmission. The apparatus of claim 1 or 2, wherein the broadcast stream encoding apparatus comprises: A CW generator for generating a CW for scrambled A / V stream provided to the CAS client; A synchronizer for synchronizing the CW generated by the CW generator with the ECM transferred from the CAS server; And EMM transmission system using an out-of-band channel, characterized in that it comprises a scrambler to scramble the A / V stream through the CW. Sends an Entitlement Management Message (EMM) related to Entitlement of a Conditional Access System (CAS) client through a mobile communication network, and sends an Entitlement Control Message (ECM) related to a key assigned to each CAS client. A conditional access system (CAS) server through a Band channel; And EMB transmission system using an out-of-band channel characterized in that it comprises a broadcast stream encoding apparatus for encrypting the ECM generated by the CAS server, and then modulated to transmit on the IB channel, and then transmitted to the IB channel. The method of claim 5, wherein the CAS client, After receiving the EMM from the CAS server through the mobile communication network, the CAS client decodes the CW (Control Word) included in the ECM through the EMM, and descrambles the scrambled A / V stream using the decoded CW. EMM transmission system using an out-of-band channel, characterized in that for displaying the corresponding broadcast channel. The method of claim 5, wherein the mobile communication network, An OTA (Over the Air) server for processing the EMM into various types of messages such as SMS and transmitting the same to the CAS client; And It acts as a message interpretation server between the CAS server and the OTA server, and includes information that can manage the sessions for each mobile carrier, and repackaged in a format that can be received by the OTA server EMM transmission system using an out-of-band channel characterized in that it comprises an I / F (interface) server for transmitting to the OTA server of the mobile communication company. The method of claim 7, wherein the I / F server, EMM transmission system using an out-of-band channel comprising a management module for managing the success / failure / error information for the EMM transmission from the OTA server to each CAS client. The method according to any one of claims 5 to 8, wherein the CAS server, In order to transmit an EMM through the mobile communication network, identifier information (Message id) indicating the EMM, CAS client information (Client id) to be transmitted, mobile communication company information (Teleco id) where the OTA server is located, and mobile communication of the CAS client EMM transmission system using an out-of-band channel, characterized in that for adding the header information including a telephone number (Teleco No) to the EMM. Sends an Entitlement Management Message (EMM) related to Entitlement of a Conditional Access System (CAS) client over an IP-based network, and sends an Entitlement Control Message (ECM) related to a key assigned to each CAS client. A conditional access system (CAS) server through an in-band channel; And EMB transmission system using an out-of-band channel characterized in that it comprises a broadcast stream encoding apparatus for encrypting the ECM generated by the CAS server, and then modulated to transmit on the IB channel, and then transmitted to the IB channel. The method of claim 10, wherein the CAS client, After receiving the EMM from the CAS server through the IP-based network, the CAS client decodes the CW (Control Word) included in the ECM through the EMM, and decodes the scrambled A / V stream using the decoded CW. EMM transmission system using an out-of-band channel, characterized in that the descrambled to display the corresponding broadcast channel. The method of claim 10, wherein the IP-based network, An IP packet routing server performing a function of delivering an EMM from the CAS server to the CAS client; And And a listening server that receives a request for a request for the CAS server and transmits the request to the CAS server when there is no key information or viewing qualification information necessary for the viewable program and / or package of the CAS client. EMM transmission system using an out-of-band channel. The method according to any one of claims 10 to 12, wherein the CAS server, EMM transmission system using an out-of-band channel, characterized in that for adding the EMM over the IP-based network, the header information including source IP address information and destination IP address information to the EMM. a) a CAS (Conditional Access System) server generating an Entitlement Management Message (EMM) through a subscriber key and a viewing credentials message, encrypting it, and transmitting the encrypted Entitlement Management Message (EMM) to a CAS client through an Out of Band (OOB) channel; b) After the CAS server encodes the subscriber key and the control word (CW), the CAS server generates an Entitlement Control Message (ECM) based on the encoded subscriber key and the CW, and encrypts the generated ECM through an encoder to perform the broadcast. Transmitting to a stream encoding apparatus; And c) the broadcast stream encoding apparatus synchronizing the encrypted ECM to the CW, and then transmitting the scrambled A / V stream to the CAS client through the IB channel based on the encrypted ECM and the CW. EMM transmission method using an out-of-band channel. The method of claim 14, wherein the OOB channel is EMM transmission method using an out-of-band channel, characterized in that the mobile communication network. The method of claim 14 or 15, wherein the step a) comprises: a-1) transmitting, by the CAS server, to the I / F (Interface) server by including header information in the EMM for managing sessions for each mobile communication company; a-2) the I / F server repackaging the EMM and header information in a format that can be received by an OTA server of each mobile communication company and transmitting the EMM and header information to the OTA server; And a-3) an EMM transmission method using an out-of-band channel, wherein the OTA server processes the EMM and header information into various types of messages and sends them to the CAS client. The method of claim 16, wherein step a-3) EMM transmission method using an out-of-band channel characterized in that the OTA server processes the EMM and header information in the SMS form. The method of claim 16, wherein the header information, EMM transmission method using the out-of-band channel, characterized in that it comprises the identifier information indicating that the EMM, CAS client information to be transmitted, the mobile communication company information that the OTA server is located and the mobile communication telephone number of the CAS client. The method of claim 14, wherein the OOB channel is EMM transmission method using an out-of-band channel, characterized in that the IP-based network. 20. The method of claim 14 or 19, wherein step a) comprises: a-1) the CAS server adding header information for IP-based network transmission to the EMM and transmitting the header information to an IP packet routing server; a-2) transmitting, by the IP packet routing server, to the CAS client through at least one or more IP-based network equipment. The method of claim 20, a-3) transmitting the EMM using the out-of-band channel, wherein the CAS client transmits a packet message containing success / failure / error information on the EMM reception to the CAS server through a listening server. Way. The method of claim 19, wherein the header information, An EMM transmission method using an out-of-band channel comprising source IP address information and destination IP address information.

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