KR100886153B1 - Conditional access system and method for synchrozing thereof - Google Patents

Abstract

A conditional access system and a synchronizing method thereof are provided to minimize the disconnection phenomenon by providing a conditional access software of the next version to a terminal in advance a next version software while receiving a broadcasting signal in the synchronization of a terminal. A head end creates program designation information by which a conditional access software for a specific channel broadcasting can be downloaded, then is transmitted to a terminal(S510). A terminal judges whether or not the received program designation information is a program which requires the change of the version of the conditional access software(S520). If so, the terminal downloads the changed conditional access software according to the program designation information(S530). A broadcasting program is available on service by executing the conditional access software based on the point when the version of the software is changed(S540).

Description

Restriction system and its synchronization method {CONDITIONAL ACCESS SYSTEM AND METHOD FOR SYNCHROZING THEREOF}

The present invention relates to a reception restriction system. More particularly, the present invention relates to a reception restriction system, and more particularly, to minimize the delay time before the reception restriction software, which is required for the next time, can be broadcasted again at a changed time point. A reception restriction system and a synchronization method thereof.

In general, a conditional access system (CAS, hereinafter referred to as "CAS") refers to a content security solution that allows only qualified subscribers to watch a corresponding channel in a pay TV system.

The CAS performs a scrambling process for video and data contents, and encrypts and decrypts restricted words and configuration keys. The headend sends scrambled content to prevent unauthorized recipients from accessing it. Then, the receiver recovers by descrambling the scrambled content.

Most CAS uses the same key as the scrambling key and the descrambling key. This is called a restriction word.

The receiver transmits the restriction word used by the scrambler of the server for descrambling. For security, the receiver encrypts the control word using an authentication key and transmits it through the qualification restriction message. The authentication key is again encrypted using the subscriber's private key, the subscriber's private key, and then sent via a credential management message.

In the subscriber management system managing customer information, the subscriber management system generates only the entitlement management message and the entitlement control message according to the subscriber's subscription and withdrawal. Then, the subscriber authentication system performs a function of receiving a broadcast channel subscribed to by a new subscriber or an unsubscribed subscriber no longer receiving a broadcast by a qualification control message. The subscriber secret key is embedded in the smart card and distributed to the subscriber through the subscriber management system. When the receiver receives the entitlement control message and the entitlement management message, the key decryption process is performed in the reverse order performed by the server after checking the message. First, the authentication key is decrypted with the subscriber secret key embedded in the smart card. It then decrypts the control word with the decrypted authentication key and uses it for descrambling.

In order to prevent market monopoly by certain major CAS vendors and to eliminate the need for content users or pay-TV service providers to replace the set-top box itself due to changes or additions to the system, the software download-based CAS is an interoperable system. Is being presented.

Software downloading-based CAS decodes the encryption key inside the entitlement management message and the entitlement control message from the existing CAS, downloads the bytecode of the module to extract the control word through the network, and executes class loading on the set-top box.

In particular, in an IPTV system that provides hundreds of channels and various programs within one channel, various content providers can suggest different CAS requirements for each channel or program in one channel.

The conventional download-based CAS focuses only on how to download the reception restriction software through the broadcasting network, and executes the newly downloaded reception restriction software when the update is needed.

However, the conventional CAS has a delay in converting the reception restriction software required to run the reception restriction software provided by one or more vendors in one set-top box as the number of channels increases, the diversification of contents, and the demand for CAS are diversified. There was a problem that occurred. As a result, a disconnection phenomenon of the broadcast program occurs, and the user has no problem but to receive a broadcast service in which a disconnection phenomenon occurs while watching a broadcast.

The present invention has been made in view of the above problems, and it is possible to minimize the delay time until the reception can be received again at the changed time by pre-downloading the reception restriction software that will be required later in the reception restriction system. It is an object of the present invention to provide a reception restriction system and a synchronization method thereof.

It is another object of the present invention to provide a reception restriction system and a synchronization method thereof in which a reception reception software according to a vendor change is downloaded in advance in one channel so that broadcast reception is possible according to a vendor change point.

It is still another object of the present invention to provide a reception restriction system and a synchronization method thereof in which a reception restriction software according to a version change is downloaded in advance in one channel so that broadcast reception can be performed at a point in time when a version is changed.

In order to achieve the above object, a headend according to an aspect of the present invention limits the viewing of a broadcast program so that a subscriber can watch a specific channel broadcast only to a subscriber. A program designation information generating unit for generating program designation information for downloading the restriction software in advance; And a multiplexer for packetizing the program designation information to be transmitted to a broadcast receiving terminal.

In addition, the terminal according to another aspect of the present invention for achieving the above object in the terminal for receiving a broadcast from the head end of the reception restriction system for restricting the viewing of the broadcast program to service a specific channel broadcast only to the subscriber, the specific A demultiplexer for parsing and outputting program designation information for pre-downloading reception restriction software for channel broadcasting; And a controller configured to control the overall operation to execute the reception restriction software in response to a broadcast that is previously downloaded and changed according to the parsed program designation information.

In addition, the reception restriction system according to another aspect of the present invention for achieving the above object in the reception restriction system for restricting the viewing of the broadcast program to watch a specific channel broadcast only to subscribers, A headend transmitting program designation information for pre-downloading reception restriction software and serving the specific channel broadcast; And a terminal configured to receive the broadcast while executing the reception restriction software in response to a broadcast that is previously downloaded and changed according to the program designation information.

In addition, the synchronization method of the reception restriction system according to another aspect of the present invention for achieving the above object in the synchronization method of the reception restriction system to limit the viewing of the broadcast program so that only the subscriber can watch a specific channel broadcast, Generating program designation information for allowing a headend to download the reception restriction software for the specific channel broadcast in advance and transmitting the same to the terminal; And downloading, by the terminal, the reception restriction software in advance in response to the program designation information, and receiving a broadcast in response to a broadcast that is changed.

According to the above-mentioned problem solving means, the present invention provides the terminal with the information of the next version of the reception restriction software in advance when the one reception restriction software needs to be replaced according to the version change, and the terminal prepares the next version of the reception restriction software in advance. By making it possible, there is an effect of minimizing the interruption during broadcast reception and providing a service quality that can be satisfied by the user in synchronization between the transmitter and the terminal.

In addition, even if the channel is fixed but other reception restriction software should be applied to a specific program, the delay time from the start of the program to the execution of new reception restriction software is also transmitted to the terminal in advance. Minimize the effect.

The reception limiting system and the synchronization method thereof according to the present invention download a reception limiting software for a broadcast program that requires a version change of the reception limiting software or a broadcast program to which the reception limiting software of another system should be applied to a specific program, thereby replacing the reception limiting software. The technical point is to reduce the delay time.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail, focusing on the parts necessary to understand the operation and action according to the present invention.

In the following description, specific details of the reception restriction system of the present invention and its synchronization method are presented to provide a more general understanding of the present invention, and the present invention may be easily implemented without these specific details and also by modification thereof. It will be apparent to those of ordinary skill in the art.

Hereinafter, a reception restriction system and a synchronization method according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing the configuration of a reception restriction system of the present invention.

Referring to FIG. 1, the CAS 100 of the present invention includes a head end 10 and a terminal 20 (set top box).

The head end 10 transmits broadcast programs of various channels. The headend 10 also provides the terminal 20 with reception restriction software. In addition, the headend 10 transmits program specific information (PSI) for requesting the terminal 20 to change the reception restriction software according to the broadcast program. In addition, the headend 10 includes a program designation information generation unit 11 for generating program designation information for pre-downloading the reception restriction software for a specific channel broadcast, and packetizes the program designation information to the broadcast receiving terminal. Receipt management message (EMM: Entitlement Management Message), including a multiplexer 13 to transmit, and a control word and encryption keys encrypted to reproduce broadcast content of a specific channel broadcast and reception restriction Provides EMM / ECM generators 15a and 15b for generating a message (ECM: Entitlement Control Message, hereinafter referred to as " ECM ") and transmitting it to the multiplexer 13, and a reception restriction software program to the terminal 20. Program download servers 17a and 17b. Here, the program designation information may be a program map table (PMT: Program Map Table. ).

The terminal 20 receives and plays a broadcast program to be played back from the headend 10. In addition, the terminal 20 receives program designation information from the headend 10, accesses the program download server, and downloads the reception restriction software in advance. In addition, the terminal 20 parses and outputs program designation information for pre-downloading reception restriction software for a specific channel broadcast, or receives a control word encrypted to play a broadcast program from a headend and transmits it to the controller. The demultiplexer 21 for reproducing the channel broadcast, and the control unit 23 for controlling the overall operation to execute the reception restriction software in response to the broadcast which is previously downloaded by changing the reception restriction software according to the parsed program designation information. And a descrambler 25 which receives a control word according to the reproduction of the broadcast program from the controller 23 and descrambles the channel broadcast.
Meanwhile, in the above-described embodiment and in FIG. 1, the transmission and reception from the headend 10 to the terminal 20 are described and illustrated as being performed by the multiplexer 13 and the demultiplexer 21. 13 and a receiver (not shown) connected to the demultiplexer 21 are obvious to those skilled in the art, and the above-described embodiment and FIG. 1 are described. It is outlined for the convenience and improvement of understanding.
For the same reason, throughout this specification, including claims, the multiplexer 13 is used to mean components encompassing multiplexers and transmitters, and the demultiplexer 21 is meant to refer to components encompassing receivers and demultiplexers.

An operation of the reception restriction system will be described with reference to FIG. 1.

First, in order to identify the download-based reception restriction software in the terminal 20, a reception restriction software identifier including a reception restriction software vendor identifier, a reception restriction software system identifier, and a version number is provided.

In the case of DVB, since the reception restriction system 100 is registered and used by the vendor, the reception restriction software identifier may be configured as the reception restriction software system identifier and the version number by combining the system identification of the reception restriction software vendor and the reception restriction software. have.

The terminal 20 parses the PSI from the demultiplexer 21 to find the PID of the EMM and the ECM packet, and transmits the EMM and the ECM to the controller 23. Then, the controller 23 transfers the EMM and the ECM to the corresponding reception restriction software CAS A and CAS B, acquires a control word, and then transfers the obtained control word to the descrambler 25. The descrambler 25 then descrambles the A / V using the control word.

On the other hand, the control unit 23 reduces the delay time required to replace the reception restriction software by receiving the reception restriction script of the program designation information from the headend 10 and downloading the necessary reception restriction software in advance.

Next, the program designation information of the present invention will be described in detail with reference to the accompanying drawings.

2 is an exemplary diagram for explaining the program designation information of the present invention.

Referring to FIG. 2, first, information related to reception restriction is provided to PMT and CAT in the form of a reception restriction descriptor among program designation information. The PMT and CAT present in the program designation information include a plurality of reception restriction descriptors.

In the MPEG2 specification, the CAP of the CAC in the PMT indicates the PID of the ECM, and the CA PID of the CAC in the CAT indicates the PID of the EMM.

Such a reception restriction descriptor includes a CAS system ID information and a reception restriction PID information field, and there is a private section in which a user can additionally write information.

In the present invention, a private section, which is a user-defined part, is used to provide information of reception restriction software required next.

The private section contains an ON / OFF information field that indicates whether the present restriction software is currently being used in the user defined portion of the restriction statement included in the CAT, the version of the current restriction software and the download server address information field, and the following: It consists of the version information of the reception restriction software, the download server address information, and the reception restriction software version change countdown information fields.

One such reception restriction descriptor has information of one reception restriction software.

The current and next are distinguished according to the version change, and include information fields for presenting the address of the version and the download server for the current reception restriction software and the address of the version and the download server for the next reception restriction software. The CAS version change countdown information field informs the time of change to the next version of the reception restriction software.

Therefore, information about reception restriction software corresponding to systems of different vendors is represented through a plurality of reception restriction descriptors in CAT. In order to indicate the reception restriction software for the current EMM and ECM among the plurality of reception restriction descriptors, the reception restriction software application ON / OFF field is displayed as ON.

3A is an exemplary diagram for describing a synchronization operation of the reception limiting system of the present invention. 3A illustrates an embodiment of synchronization according to a system change of the reception restriction software in one channel.

Referring to FIG. 3A, the current channel is in a state where a conditional access service is applied to a conditional access system A, and a conditional access system B is applied to a specific program.

To this end, the PSI generation unit 11 includes not only the reception restriction descriptor for the reception restriction software A, but also the reception restriction descriptor for the reception restriction software B in the CAT before a predetermined time (eg, several tens of minutes) before the program is broadcast. Transfer to 20. In this case, the structure of the reception restriction descriptor transmitted from the PSI generation unit 11 to the terminal 20 is as shown in FIG. 3B.

In addition, the CAS applied ON / OFF field in the reception restriction descriptor for the reception restriction system A is turned ON, and the CAS applied ON / OFF field in the reception restriction descriptor for the reception restriction system B is displayed as OFF. do.

At this time, since the terminal 20 hardly knows the exact time of changing from the reception restriction software A to the reception restriction software B, at the overlapping time point, the terminal 20 processes both the EMM and the ECM for the reception restriction software A and the EMM and the ECM for the reception restriction software B. do.

Thus, the descrambler 25 receives two control words (CW: " CW " hereinafter) to take the correct one out of the two.

4A is an exemplary diagram for describing a synchronization operation of the reception limiting system of the present invention. 4A illustrates an embodiment of synchronization according to a version change in one channel.

Referring to FIG. 4A, the current channel is applying the reception restriction service of the version 1.1 of the reception restriction system A. After a specific time, the channel is serviced by the reception restriction system of the version 1.2.

To this end, the PSI generation unit 11 includes the next reception restriction software version and the download server address in the reception restriction descriptor for the reception restriction software A in the CAT and transmits it to the terminal 20 from a predetermined time (for example, several tens of minutes) to be updated. do. In this case, the structure of the reception restriction descriptor transmitted from the PSI generation unit 11 to the terminal 20 is as shown in FIG. 4B.

As the version change time of the conditional access software is imminent, the CAS version change countdown information field inside the conditional access descriptor for the conditional access system A becomes less and less, and becomes '0' at the time of the change.

Since the terminal 20 does not know exactly when to change, at the time of overlapping, it processes both the EMM and ECM for version 1.1 and the EMM and ECM for version 1.2, and sends two CWs to the descrambler to take the correct one. .

5A and 5B are flowcharts illustrating a synchronization method of a reception restriction system of the present invention.

5A and 5B, the headend 10 generates program designation information for pre-downloading the reception restriction software for the specific channel broadcast and transmits it to the terminal 20 (S510).

At this time, the headend 10 determines whether there is a version change of the reception restriction software (S610).

As a result of the determination, if there is a version change, the headend 10 transmits the changed program designation information for allowing the receiving terminal to change the reception restriction software version according to the version change of the reception restriction software (S620).

That is, the current CAS version and the current CAS download server address information field are set, and program designation information in which the next CAS version and the next CAS download server address information field are set is transmitted.

However, as a result of the determination, if the version is not changed, the headend 10 may change to the reception restriction software of the other system when the reception restriction software of the corresponding system whose system is changed is applied to a specific program among the broadcast programs. The changed program designation information is transmitted (S630).

That is, the CAS application information field is turned on in the reception restriction descriptor corresponding to the current channel, and the current CAS version and the current CAS download server address information field are set. The CAS application information field is turned OFF in the reception restriction descriptor corresponding to the specific broadcast program, and the current CAS version and the current CAS download server address information field are set and transmitted.

Then, the terminal 20 determines whether the received program designation information is program designation information for requesting a version change of the reception restriction software (S520).

If the determination result is requested to change the version of the reception restriction software, the terminal 20 downloads the reception restriction software whose version is changed according to the program designation information (S530).

Thereafter, the terminal 20 executes the reception restriction software in accordance with a time point when the version of the reception restriction software is changed to service the broadcast program (S540).

However, if it is determined that the download of the reception restriction software corresponding to the specific program is requested, the terminal 20 downloads the reception restriction software of another system according to the program designation information (S550).

Thereafter, the terminal 20 executes the reception restriction software corresponding to the specific program to service the broadcast program (S560).

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

1 is a block diagram showing the configuration of a reception restriction system of the present invention.

2 is an exemplary diagram for explaining program designation information of the present invention.

Figure 3a is an exemplary diagram for explaining the synchronization operation of the reception restriction system of the present invention.

3B is an exemplary view showing a reception restriction descriptor in the operation of FIG. 3A.

Figure 4a is an exemplary view for explaining the synchronization operation of the reception restriction system of the present invention.

4B is an exemplary view showing a reception restriction descriptor in the operation of FIG. 4A.

5A and 5B are flowcharts illustrating a synchronization method of a reception restriction system of the present invention.

Claims (15)

In the headend of the software-based reception restriction system that restricts the reception of the broadcast program to allow subscribers to watch the broadcast program, A program designation information generation unit for generating program designation information including a reception restriction descriptor to which at least current reception restriction software information, next reception restriction software information, and countdown information have been added, from a predetermined time before the scheduled replacement time of the reception restriction software; Multiplexer for transmitting the program designation information to the broadcast receiving terminal Including; And the countdown information indicates a remaining time until a replacement time point of the reception limiting software. The method of claim 1, An EMM / ECM generation unit for generating and encrypting a control word for decoding broadcast content, generating an entitlement management message (EMM) and an entitlement restriction message (ECM), and delivering the entitlement management message to the multiplexer; And a program download server for providing a reception restriction software program to the broadcast receiving terminal. The method of claim 1, wherein the program designation information generating unit, And program designation information including a first reception restriction descriptor for allowing the receiving terminal to change the reception restriction software version according to the version change of the reception restriction software. The method of claim 3, wherein the first reception restriction descriptor, A head comprising system identification information of the reception restriction software, current reception restriction software version information, current reception restriction software download server address information, next reception restriction software version information, next reception restriction software server address information, and countdown information. End. The method of claim 1, wherein the program designation information generating unit, When reception restriction software of another system is to be applied according to the broadcast program, program designation information including a plurality of second reception restriction descriptors including current and next reception restriction software information for each broadcast program is generated. Headend. The method of claim 5, wherein the second reception restriction descriptor, And a current reception restriction software download server address information and next reception restriction software version information, next reception restriction software download server address information, countdown information, and current application information. A terminal for receiving a broadcast from a headend of a software-based reception restriction system that restricts reception of a broadcast program to allow a subscriber to watch a broadcast program. A demultiplexer for parsing program designation information transmitted from the headend and outputting current reception restriction software information, information of a next reception restriction software, and countdown information indicating a remaining time until a replacement scheduled time; According to the parsed program designation information, the next reception restriction software is downloaded in advance before the replacement scheduled time, and each control word is acquired using both the current reception restriction software and the next reception restriction software at the replacement scheduled time. Control Terminal comprising a. The method of claim 7, wherein And a descrambler configured to descramble a channel broadcast by receiving a control word according to the reproduction of the broadcast program from the controller. The method of claim 8, wherein the descrambler, At the time of the replacement, the terminal receives both the control word by the processing of the current reception restriction software and the next reception restriction software from the controller, and descrambles using the control word among them. The method of claim 7, wherein the next reception restriction software information, And a download server address and a version of the reception restriction software to be used after the scheduled replacement time. The method of claim 10, wherein the control unit, And accessing the download server indicated by the download server address to download the next reception restriction software to an out-of-band channel. A software-based reception restriction system that restricts reception of a broadcast program so that only a subscriber can watch the broadcast program. A headend for transmitting program designation information including a reception restriction descriptor including a next reception restriction software information and a countdown information indicating the replacement scheduled time from a predetermined time before a replacement time of the reception restriction software; The next reception restriction software is downloaded in advance before the scheduled replacement time by referring to the reception restriction descriptor in the program designation information, and at the replacement scheduled time, at least two control words are used by using both the current reception restriction software and the next reception restriction software. Terminal to acquire and use the appropriate one among them Reception restriction system comprising a. A method for synchronizing a software-based reception restriction system that restricts reception of a broadcast program so that only a subscriber can watch the broadcast program. If replacement of the reception restriction software in the terminal is necessary, the program designation includes at least one version of the reception restriction software and one or more reception restriction descriptors to which information on the replacement timing point is added, at least before a predetermined time of the replacement scheduled date. Generating information, Transmitting the program designation information to the terminal a plurality of times until a replacement scheduled time; Method of synchronizing the reception restriction system comprising a. The method of claim 13, wherein the generating step, If the replacement is necessary according to the version change of the reception restriction software, program designation information including at least one version of the next reception restriction software, a download server address, and one reception restriction descriptor to which replacement time information is added is generated. If different reception restriction software is to be applied for each broadcast program, program designation including two or more reception restriction descriptors including current and next reception restriction software, download server address, replacement scheduled time information, and current application information, respectively; Generating information Method of synchronizing the reception restriction system characterized in that. The method of claim 13, Receiving the program designation information; Analyzing the reception restriction descriptor in the program designation information to determine when to replace the reception restriction software, a version of the next reception restriction software, and a download server address; Before the replacement time point, accessing the download server to receive the next reception restriction software; At the time of the replacement, acquiring at least two control words using both the current reception restriction software and the next reception restriction software to select and use a suitable one. Method for synchronizing the reception restriction system further comprising.

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