WO2024035279A1

WO2024035279A1 - Encrypting and descrambling virtual channel service content

Info

Publication number: WO2024035279A1
Application number: PCT/RU2023/050045
Authority: WO
Inventors: Дмитрий Геннадьевич РОЗОВ; Максим Станиславович САМСОНОВ
Original assignee: Общество с ограниченной ответственностью "Цифра"
Priority date: 2022-08-12
Filing date: 2023-03-06
Publication date: 2024-02-15

Abstract

A system and method for encrypting virtual channel service content and descrambling same comprises, on a transmit side, an EPG server equipped with means for generating service metadata, scheduling events on virtual channels and selecting content events from linear broadcasting channels, said events being broadcast consecutively within the framework of the service and simultaneously with the corresponding broadcast of the event by the linear channel. In addition, a CAS subsystem of the service is equipped with means for generating control words CW encrypted with session keys, as well as means for generating ECM and EMM messages containing same, for each linear and virtual channel, or groups thereof, and establishing access rights to a broadcast of said virtual channels of the service and of the linear transmission channels, wherein the same content event broadcast by different channels is encrypted with a common control word encrypted with different session keys for each linear and virtual channel, or groups thereof, and a receive side is equipped with means for processing EMM and ECM messages to establish access rights to each content event, as well as with means for descrambling content using a CW.

Description

ENCRYPTION AND DESCRAMBLING OF VIRTUAL CHANNEL SERVICE CONTENT

Purpose and scope

The group of inventions relates to the field of satellite broadcasting and can be used in its organization and the creation of dedicated “virtual” television channels.

Prior Art

Digital television systems are often characterized by the presence of a large number of mainly audiovisual channels, which the user can switch and display according to his desire (provided he has the appropriate access rights to each channel). Therefore, the choice of various materials that can be viewed at any time is very extensive, which provides the user with the opportunity to personalize television to a certain extent “for themselves.” However, for most users, keeping track of all the content on offer, categorizing it precisely according to their tastes, and scheduling ("programming") the output of programs of interest to them is either too difficult or not suited to their inclinations.

In addition, broadcast advertising materials, which are a significant (and often vital) source of income for a broadcaster, are usually of interest only to a relatively small part of television viewers. At the same time, targeted delivery of advertising materials to the relevant target groups is often difficult (and in most conventional digital television systems, completely impossible) and ineffective.

Publication US20060156341 (Samsung Electronics Co Ltd, 2005) discloses a virtual channel generating device solution comprising a virtual channel setting module for setting any one channel from a plurality of channels as a virtual channel per user; and a virtual channel processing module for registering a program selected by a user who has installed the virtual channel in a list of programs associated with the virtual channel. A virtual channel can be set for each user, so that a program to suit every taste can be viewed, even if multiple users are using the same TV, with minimal manual input required via the remote control or the TV's built-in selection buttons.

US20040205815 (Microsoft Technology Licensing LLC) discloses a solution in which an implementation associates a virtual channel with each of one or more recorded programs. A guide is being generated Virtual Channel Preview to display various virtual channels and their associated recorded programs. When you select a virtual channel, a preview of the recorded program associated with the virtual channel starts. In another implementation, the virtual channel preview guide includes program identifiers, each of which corresponds to a recorded program, and includes virtual channel identifiers, each of which is associated with a different program identifier. The virtual channel preview guide also includes a selectable control, such as a program ID or virtual channel ID, that can be selected to trigger a preview of the recorded program. In addition, the virtual channel preview guide includes a preview to display a preview of the recorded program.

From the publication of the patent for the invention RU 2541923 (VIAXESS (FR), 2011), a solution to the method of transmitting and receiving multimedia content is known, according to which the method contains the stages of: encrypting the control word CWt using the transmitter using the working key and the executable code of the encryption algorithm, contained in the virtual mother card, to obtain the Enlarged Image cryptogram (opens in a separate window), generate an ECM message (entitlement management message) containing the Enlarged Image cryptogram (opens in a separate window), using the executable syntax constructor code within the virtual mother card and transmitting the specified ECM message to the terminal device, receiving the ECM message using the terminal device, locating the Large Image cryptogram (opens in a separate window) in the received ECM message through executable syntax analyzer code, and then decrypting the Large Image cryptogram (opens in a separate window) ) using the working key and decryption algorithm. This solution is aimed at increasing the security of data transmission through multi-level encryption. The disadvantages of this solution include the limited possibilities of applying this solution to individual multimedia objects, without the possibility of forming a virtual channel based on existing linear channels without increasing the transponder capacity.

The closest solution to the solution under study is the technology for forming user channels disclosed in patent publication US20090320072 (Microsoft Corporation, 2008). The technology is a system and method for generating a virtual channel in an electronic program guide. Scheduling commands, which are customizable by the user, specify the content that should be presented for selection in the virtual channel. Scheduling instructions are executed in order of priority. The virtual channel is populated with content descriptions based on the execution of instructions planning. After the virtual channel is initially filled with content, broadcast intervals are defined in the virtual channel. In one embodiment, each broadcast interval is filled with different content based on the broadcast interval setting set by the user. In another embodiment, each broadcast interval remains an empty schedule entry on the virtual channel.

The disadvantages of the above analogues and the prototype include the need for the formation and use of a virtual channel to increase the used transponder capacity, to organize the recording of the content of the virtual channel and the presence of an additional storage device for storing the recorded content, as well as the need for the content reproduced as part of the virtual channel to be completely descrambled , both within the virtual channel and outside it. In addition, known solutions are built, mostly based on user preferences, i.e. is formed on the client device, which complicates the process of forming this kind of individual channel, and also reduces the protection of the recorded content. Thus, known solutions for organizing a virtual channel require significant complication of the broadcasting system while reducing the level of content protection and increasing the risk of providing unauthorized access to programs of linear broadcast channels. The limitations of known solutions are especially significant when it comes to organizing a virtual channel based on high-quality content. In this case, in addition to the significantly increasing above-mentioned technical problems, the cost of the solution for the broadcast operator also increases significantly, incl. due to the need to significantly expand the transponder capacity (due to the high bitrate of the content), as well as increasing the risks of losing control over expensive content (piracy).

The essence of the invention

The technical problem solved by the claimed group of inventions is to eliminate the problems inherent in the prior art.

The technical result achieved by the claimed invention is to expand the operational capabilities of the broadcasting system by expanding the capabilities of broadcasting content without increasing the transponder capacity and memory capacity of the transmitting and client parts, while simultaneously increasing the level of content protection.

The claimed technical result is achieved by using a system for encrypting the content of the virtual channel service and descrambling it, including at least an EPG server for the electronic program of television programs formed on the transmitting side and connected to each other and to the multiplexer by communication lines, equipped with means for generating a schedule of linear content events broadcast channels, and a conditional access subsystem CAS, including an encrypting device equipped with means of encryption and access control to the encrypted content of linear channels, and the multiplexer is equipped with at least means formation of a transport stream broadcasting linear channels, characterized in that

- the EPG server is additionally equipped with tools for generating metadata of virtual channels, and scheduling virtual channels based on the formation of a thematic selection of content events of linear broadcast channels, selected according to parameters preset for each virtual channel and broadcast within the virtual channels of the service sequentially in time, with a setting for each sample content events of the identifier of each corresponding virtual channel in the schedule of which the content event is included and usage marks of each content event within each corresponding virtual channel;

- and the CAS subsystem contains hardware-software transmitting and receiving parts, where the transmitting part includes an SMS subscription management system connected to the billing system, equipped with means for generating CW control words with encryption of their session keys, as well as means for generating ECM and EMM messages containing them, for each linear and virtual channel of the service or their group, with the establishment of access rights to broadcast the specified specified virtual channels of the service and linear broadcast channels, in the schedule of the event of the linear channel as part of the virtual channel and its suspension at the end of the event., and one and the same content event broadcast by different channels is encrypted with a common control word, encrypted with different session keys for each linear and virtual channel or their group, and the receiving part is equipped with means for processing EMM and ECM messages to set access rights to each content event, receive and decrypting CW-based descrambling keys of each content event included in each service virtual channel, respectively, as well as CW-based descrambling means.

In one of the possible embodiments of the claimed solution, the CAS conditional access subsystem can be equipped with content encryption tools so that the same broadcast event is encrypted with a common control word, which in turn is additionally encrypted with different session keys for each linear and virtual channel or their groups. In this case, the CAS conditional access subsystem can be equipped with content encryption tools in accordance with the DVB CSA algorithm.

In another possible embodiment of the claimed solution, the transport stream at the output of the multiplexer is an MPEG-2 transport stream and includes at least: linear broadcast channels, the content of which is also used as part of virtual channels; basic and additional metadata of the virtual channel service; Linkage handle; MPEG-2 transport stream service tables including: RMT program structure table; CAT conditional access table; NIT network information table; TDT date and time table; BAT table of program groups. In another embodiment, the virtual channel metadata can be generated with the ability to broadcast in one service on one transponder, and provided with service information with a link to the virtual channel metadata service with the ability to detect the metadata service in the transport stream. In this case, the service information can be provided with a Linkage descriptor added to the network information table of the NIT stream, making it possible to provide virtual channel service to the end user without a user feedback channel. Moreover, the service information of the Linkage descriptor may include at least: parameters for broadcasting SNT virtual channel metadata, a service identifier with virtual channel metadata, and a version of the virtual channel metadata format.

In a possible embodiment, the receiving part may include at least a tuner/demodulator that restores the incoming encrypted transport stream in the input signal modulated by the multiplexer and transmits it to the input of the CAS module cryptomodule, equipped with a conditional access system library installed in hardware and software, integrated into receiving device (STB) for descrambling linear and virtual channels in accordance with subscriptions, providing the ability to descramble an incoming encrypted transport stream and transmit it to the input of the main CPU processor, configured to provide the ability to decrypt an incoming encrypted transport stream, through a built-in security system implemented in software - in hardware, and based on a pre-installed software and hardware algorithm, processing of data, providing the end user with audio-video output of the content of channels in the user interface module, while the CPU is equipped with a sectional filter of commands for setting virtual channel rights, a handler of EMM type messages corresponding virtual channel and the ability to send a command to set the rights and session keys of the service’s virtual channel. Whereas, the cryptomodule can be paired with a SmartCard smart card or equipped with a built-in smart card emulator SmartCard emulator containing keys and access rights to content

In accordance with any possible embodiment of the claimed solution, the transmitting part of the CAS subsystem may at least include means for generating EMM and ECM messages, connected by feedback lines to a means of encrypting CW control words with session keys, and one of the inputs of the generating means The ECM messages are connected to the output of the EMM message generation means, and the other two inputs are connected via feedback lines to the EPG server and the SCS synchronizer of the CW generation processes, the output of which is connected to the MUX multiplexer connected to the transport stream encryption means with C\U keys (scrambler) , connected to a means for modulating the transport stream and transmitting it to the receiving part, while the second input of the generating means The message EMM is connected to the SMS subscription management system connected to the billing system.

The claimed technical result is also achieved by using the method of encrypting content and generating data implemented in the above-mentioned system for descrambling the service for providing virtual channels, including sequentially performed stages in which at least:

- form, according to preset criteria on the EPG server of the transmitting party, a directory of virtual service channels containing at least the name of the channels and their position number in the list of broadcast channels, and a schedule of events of virtual service channels by arranging a selection of content events of linear broadcast channels broadcast within virtual channels of the service sequentially in time and simultaneously with the corresponding broadcast of the linear channel event, setting for each sampling event the identifier of the corresponding virtual channel and marking the use of the event in its composition, with the subsequent generation of metadata for each virtual channel.

- receive and encrypt control words generated by the scrambler of the conditional access subsystem, generate session keys and ECM and EMM messages containing them ECM and EMM messages of linear broadcast channels and virtual channels of the service system, and encrypt the same event broadcast as part of the linear and virtual channels carry out a common control word additionally encrypted with various session keys for each linear and virtual channel or their group with setting access rights to broadcast the event of a linear channel specified in the schedule as part of a virtual channel and its suspension at the end of the event, and transmit metadata files of the virtual channel service to the input multiplexer, where they form a transport stream by embedding service metadata into the transport stream of content of linear broadcast channels and transmit it to the input of the client device.

In one of the possible embodiments of the claimed solution, the group of inventions additionally carry out on the transmitting part of the CAS server the generation, storage, application and automatic updating on a schedule of session keys of CAS technology packages used to control access to broadcast events of linear channels through a virtual channel.

In this case, in another possible embodiment, the transmitting part of the CAS server additionally generates EMM messages with access control commands and session keys for technology packages of virtual channels, ensuring control of subscriber access to the content of the virtual channel service in modes in accordance with data on existing subscriptions, received from the billing system and/or free access of subscribers with authorized equipment and activation functionality of virtual channels according to parameters preset in the system.

It is also possible to implement the claimed solution, in which, when forming an MPEG-2 transport stream using a multiplexer, additional service information is built into the transport stream, which is subsequently transmitted to the input of the client device, which is a Linkage descriptor in the network information table (NIT), providing dynamic detection by the client device metadata of the virtual channel service in the transport stream, and on the client device, discovering the service with the metadata in the transport stream through said Linkage descriptor without a user feedback channel.

According to the claimed solution of the group of inventions, in any embodiment, it is possible, when generating a schedule of virtual channels of the EPG service by the server, when sampling events for a virtual channel broadcast by different linear broadcast channels intersect in time, an event with an earlier broadcast time is added to the schedule, and during the absence displaying events of linear broadcast channels, a technological event pre-installed in the service system is added to the virtual channel schedule.

The claimed technical result is also achieved by using a method for descrambling the encrypted content of a virtual channel service, which includes stages sequentially carried out by a virtual channel service processing algorithm installed in the receiving part of the CPU in hardware and software, including at least:

- detection of a service with metadata of virtual channels in the transport stream;

- filtering and processing EMM and ECM messages with commands for setting rights and session keys for accessing events included in virtual channels, as well as decoding control words for decrypting content events included in virtual channels;

- obtaining metadata of virtual channels and adding virtual channels in the STB user interface based on their parameters in the list of linear channels;

- creating a schedule of virtual channels and displaying it in the corresponding user interface module;

- processing the installation of rights and keys of a virtual channel from a stream;

- based on confirmed access rights, playback of the content of a virtual channel by automatically switching to a linear broadcast channel that broadcasts content events according to the schedule of the selected virtual channel, decoding the content of the linear broadcast channel broadcast as part of the selected virtual channel using control words if they are successfully decrypted; Moreover, in one of the possible embodiments of the claimed solution of the group of inventions, in the mode of automatic switching to a content event of a linear channel as part of a virtual service channel, the main CPU processor in a software and hardware manner generates and sends a request to the cryptomodule to descramble the corresponding content, and the cryptomodule initiates an appeal to a smart card or a smart card emulator built into the cryptomodule to decrypt the control word for descrambling the content of the virtual channel and configures the elementary streams for the descrambler in accordance with the information in the RMT service table for receiving ECM messages, and also sets the CW control words received from smart cards, providing the ability to decrypt the incoming encrypted stream using a built-in security system.

It is obvious that both the previous general description and the following detailed description are given for example and explanation only and are not intended to be limiting of the claimed group of inventions.

Any feature relating to one aspect of the invention may be applied to other aspects of the invention in any suitable combination. In particular, features of aspects of methods can be applied to aspects of systems and devices, and vice versa.

Brief description of drawings

Below, by way of illustrative examples only, preferred features of the invention will be described with reference to the accompanying graphical figures: FIG. 1 is a general diagram of a broadcast network; Fig.2 is an example of generating a schedule with setting a technological break mark: a) one virtual channel; b) two virtual channels; Fig.3 - general diagram of the transmitting part of the CAS; Fig.4 is a generalized diagram of a client device; Fig.5 - logic for controlling subscriber access to virtual channels, where SK is the session key; CWi (SKp - i-ordinal control word CWi encrypted with i-ordinal session key SKi; CP ID - CAS package identifier; Fig.6 - process of detecting a metadata file; Fig.7 - operation of the virtual channel service on the client device when interacting with the user; Fig.8 - switching according to the virtual channel schedule.

It should be noted that the accompanying drawings illustrate only a portion of some of the most preferred embodiments of the invention and should not be construed as limiting its contents, which include other embodiments thereof.

Feasibility of the invention.

The claimed group of inventions relates to the field of organizing satellite broadcasting, namely to a system and method for encrypting content and generating data for descrambling the service of providing virtual channels to the end user.

As part of the description of an example of the implementation of the stated solution, the following terms and abbreviations are used:

AC (Access Criteria) - access criterion, information necessary for the access control message generator (ECMG) to generate an access control message (ECM);

CAS (Conditional Access System) - access restriction system; SOD;

CW (Control Word) - control word/control words: data object used for scrambling (low-level operational key that carries out the scrambling and descrambling process. CW changes with a frequency of 10 to 20 s);

CWG (Control Word Generator) - control word generator;

DVB (Common Scrambling Algoritm) - a unified scrambling algorithm;

ECM (Entitlement Control Message) - a message that controls access rights;

ECMG (Entitlement Control Message Generator) - ECM message generator;

EMM (Entitlement Management Message) - a message granting access rights;

EMMG (Entitlement Management Message Generator) - EMM message generator;

ES (Elementary Stream) - elementary stream of video data (sound data, special data) of digital broadcast television;

MPEG (Motion Pictures Expert Group) - a group of video and audio data compression standards;

MUX (Multiplexer) - multiplexer, a device designed to combine several data streams of a digital television signal into a single stream with the addition of service bits;

PID (Packet Identifier) - packet type identifier;

SAS (Subscriber Authorization System) - a system for granting authorization to a subscriber (subscriber authorization system): a system that ensures the organization, ordering and delivery of data for the generation of messages granting access rights (EMM) and ECM messages;

SCR (SCR DVB Compliant Scrambler; scrambler) - a scrambler corresponding to DVB technology: a device designed to transform the structure of a digital telecommunication signal, without changing the symbol rate of this signal, in order to bring its properties closer to the properties of a random signal;

SMS (Subscriber Management System) - a subscriber administration (management) system: a subscriber information recording system containing a database of subscribers, subscriber decoders, services (services) to which subscribers have subscribed, settlements with subscribers and payment accounting, received from subscribers; TS (Transport Stream) - transport data stream of digital broadcast television; TP;

Multiplex (multiplex) - transport stream at the output of the transport multiplexer;

As follows from the diagrams shown in Fig. 1-8 example implementation, the service system for providing virtual channels to the end user (virtual channel service) consists of functionally interconnected transmitting 1 (operator) and receiving 2 (client) sides, where the transmitting side includes 3 communication lines connected to each other and to the multiplexer an electronic program program server 4 (EPG server) and a conditional access subsystem 5 CAS (CAS subsystem), including a conditional access server 6 CAS (CAS Server) and an encrypting device 7, in particular, as shown in the diagram of Fig. 1, a scrambler (Scrembler ; SCR), equipped with means of encryption and providing access to encrypted content of linear channels. As the receiving side 2, a client device is used - a digital satellite receiver 8 (set-top box, STB), equipped with at least a tuner/demodulator 18 (Tuner/Demodulator), which receives the input MPEG-2 transport stream signal and transmits it after processing to the input of the crypto module 19 (C AS module), which is responsible for descrambling the incoming coded stream, the input of which is connected to the input of the main processor 23 (CPU), which processes the data and transmits the audio-video signal presented to the end user by the user interface and channel content, to audio-video output. According to the claimed solution, the EPG server input is connected to external control systems, in particular, control of algorithms preinstalled in the EPG server memory for implementing the claimed solution by entering the necessary data by the operator, and/or head equipment systems in automatic mode. In this case, one of the EPG server outputs is connected to the first input of the CAS subsystem, and the second is connected to one of the multiplexer inputs. The second input of the CAS subsystem supplies audio/video content of the satellite broadcasting system. As noted above, in the generalized implementation diagram of the claimed solution, presented in the diagram of Fig. 1, the AS Server and the scrambler are connected to each other via a feedback line and are equipped with outputs connected to the corresponding inputs of the multiplexer.

The functional connection between the transmitting and client parts of the virtual channel service provision system is provided by a data transmission channel, which uses a satellite signal (Transport Stream; TS), MPEG-2 transport stream (ISO/IEC standard 13818-1, ETSI TS 102 154), generated by the transmitting side multiplexer and received by the client device.

The modules, subsystems, equipment and hardware or structural elements and devices included in the virtual channel service system are equipped with hardware, structural and/or software And hardware that provides the functionality of the specified elements of the virtual channel service system in accordance with the stated solution. The specified design and hardware means do not go beyond the generally accepted design solutions for the specified system elements. At the same time, their functionality, directly or indirectly, being in the constructive or functional unity of the system elements, is regulated by specified software and hardware algorithms, preinstalled in the memory of the programmable hardware of the satellite broadcasting system to the end user, controlling the hardware and design of the virtual channel service system.

The EPG electronic television program server (EPG server; EPG server), as part of the transmitting side of the virtual channel service system, is a server equipped with a memory unit (not shown in the diagram), which initially stores the program schedule for all operator channels, and is equipped with means for generating an event schedule content of linear broadcast channels, metadata and schedule of virtual channels of the service. Moreover, the schedule of each of the virtual channels of the service is formed in the form of a layout of a sample of content events of linear broadcast channels, selected according to criteria preset for each virtual channel and broadcast within the virtual channels of the service sequentially in time, with the identifier of the corresponding virtual channel and mark set for each sampling event using the event as part of it. To generate the specified selection of EPG events, the server provides the generation of metadata for virtual channels, including basic data: their name, position in the general list of channels, program schedule, as well as additional data, for example, logos, virtual channel icons and banners. At the same time, the EPG server also implements the formation and generation of service metadata and carousels for broadcasting metadata.

In the general case of implementing a virtual channel service solution, the CAS conditional access subsystem within the stated solution consists of a transmitting and receiving part. According to the diagram shown in Fig. 3 example of the implementation of the claimed solution, the transmitting part of the CAS interacts with the EPG server 4, the billing system 16, the multiplexer 3, as well as the receiving part 2 of the CAS and the virtual channel service system as a whole, providing protection and rules for user access to the content of linear and virtual channels for encryption account and provision of access to encrypted content of linear broadcast channels (linear channels) and virtual service channels, based on the schedule of virtual channels received from the EPG.

As follows from the embodiment of the claimed solution presented in the diagram in Fig. 3, the CAS subsystem on its transmitting side can be conditionally divided into a server part 5 and a part located on the head equipment 17. This division is more convenient for identifying the functional connections of the elements of the CAS subsystem, however , for a specialist in the field It is clear from the art that the CAS solution can be implemented with a different distribution of system elements included in the server part or head-end equipment, as well as using a different distribution of subsystem elements used in the art.

In accordance with the presented implementation example, the server part of the C AS subsystem is connected to the billing 16 system through the SMS 13 subscription management system, the output of which is connected to one of the inputs of the EMMG 9 generator, designed to generate EMM messages that form the right of access to the content of linear and virtual channels service, the second input of which is connected via feedback lines to an encryptor 14 (Encryptor), designed to encrypt CW control words and session keys. Encryptor 14, in the example implementation under consideration, is implemented on the basis of a specialized cryptoprocessor, which allows cryptographic operations to be performed in hardware in a secure mode. The second input of the Encryptor, also via feedback lines, is connected to the second message generator ECMG 11, designed to generate ECM control messages, the second and third inputs of which are connected to the EPG server 4 and the generator EMMG 9, respectively. In this case, the generator ECMG 9 is connected via feedback lines through the synchronizer SCS 12 with the control word generator 10, the scrambler SCR 7 and the transport stream multiplexer MUX 3 (multiplexer), referred to in the diagram of Fig. 3 as the part associated with the head equipment.

Since multiplexer 3 generates a single transport stream from all input data, including insertion into the transport stream of linear channels and virtual channels of EMM messages received from EMMG 9, the input of multiplexer 3 is also connected to the outputs of the EMMG 9 generator and EPG 4 server, and the output is connected to the second input of the scrambler SCR 7, which provides encryption of the transport stream with CW keys using the Common Scrambling Algorithm (CSA) and, in turn, is connected to the modulator 15 (Modulator), the output data of which is transmitted to the receiving device.

To implement the tasks of providing a virtual channel service, the transmitting part of the CAS implements the assembly of ECM and EMM messages that are sent to subscribers (end users, receiving equipment used by end users in the content broadcast system) to decrypt the secure transport stream, subject to a valid subscription. Thus, C AS allows you to manage subscriber access to its services for the implementation of service services. To control access, the transmitting part of the CAS performs the following actions:

1. At the first start, EMMG generates initial values of session keys, saves them in the CAS database and transmits them to ECMG to encrypt CW control words (step - si, Fig.3).

2. The SMS subscription management system receives from the billing system, processes and stores data on subscriber subscriptions to channel packages (step s2, Fig. 3), including: - a unique identifier of the subscriber’s smart card, used by the billing system and the CAS subsystem to identify the subscriber and address commands transmitted in EMM messages;

- a unique channel package identifier used by the billing system and the CAS subsystem to identify the set of channels to which access is granted within the framework of a given subscription.

- subscription start date and time used by CAS to control subscriber access to viewing a given channel package.

- subscription expiration date and time used by CAS to control subscriber access to viewing a given channel package.

3. To generate and distribute rights and session keys according to current subscriptions, the EMMG generator, with the frequency specified in its settings, generates and sends a corresponding request to the SMS subscription management system, which responds with a list of current data (step s3, Fig. 3).

4. The EMMG generator sends requests to encrypt session keys (sk) to Encryptor, which encrypts them and returns them in encrypted form (sk') to EMMG (step s4, Fig. 3), and EMMG generates and transmits them to the multiplexer (MUX ) EMM messages (EMMs(sk'), Fig.3) according to the protocol of the DVB-Simulcrypt standard (ETSI TS 103 197) (step-sS, Fig.3), which at least contain:

- identifier of the CAS technology package, which is used to control access to channels.

- subscribers’ rights to access channel packages in accordance with current subscriptions.

- identifier and value of session keys necessary for decrypting CW control words in the ECM message for channel descrambling.

5. At the next stage, the EMMG generator generates new session keys (sk) according to a schedule, which it saves in the CAS database and transmits to ECMG for CW encryption by analogy with step 1 (si Fig 3), starting a new cycle.

6. At the same time, when the scrambler changes at a given interval, usually 10-20 seconds, CW, upon request from the SCS synchronizing component (step s7, Fig.3), the ECMG generator transmits (step s8, Fig.3) the keys to Encryptor ( sk) to encrypt the CW, and then the ECMG packs the session key-encrypted control words (CW) into the ECM message and returns the ECM message (ECMs(CW'), FIG. 3) to the SCS in response to its request (step s9, FIG. H) for transmission to the scrambler and MUX (step -slO, Fig.3) messages containing data necessary directly for descrambling encrypted channels by STB equipment:

- control words encrypted with session keys s(CW');

- identifiers of the session key instance (sk), which encrypts copies of the current CW; - identifier of the CAS technology package, subscription to which determines access rights to view channels of the corresponding channel package through access to the session key.

Thus, the subsystem C AS is equipped with means of encrypting CW control words, generating and encrypting session keys, as well as generating ECM and EMM messages containing them, for each linear and virtual channel of the service system or their group, with the same content event broadcast different channels, performed by an encrypted common control word, encrypted with different session keys for each linear and virtual channel or their group.

According to the claimed invention, the ECM generator (ECMG), which is part of the transmitting part of the CAS, implements the assembly of ECM messages upon request of the head equipment (SCS). At the same time, the CW required to decrypt the channels from the transport stream on the receiving side is transmitted to the ECM in encrypted form.

In this case, the EMM generator (Entitlement Management Message Generator, EMMG) implements the assembly of EMM messages with access control commands to channel packets on the receiving side. The EMM must contain the rights (information about access rights to content) and session keys necessary to decrypt the CW. In accordance with the specified schedule, EMMG polls SMS and initiates the collection of EMM messages. The received EMMs are transmitted to the head equipment (MUX) using the DVB-Simul crypt standard protocol with the organization of cyclic distribution with repetitions of commands in the transport stream. According to the claimed invention, the MMG also generates and updates the necessary session keys in accordance with a given schedule.

In accordance with the claimed solution, the multiplexer (Multiplexer) of the transmitting part is equipped with means for generating a transport stream by embedding into it at least the content of linear broadcast channels, a schedule of content events, and commands for accessing encrypted content. In this case, the formation of a transport stream (Broadcast Stream) is carried out by embedding into the transport stream media content received as input from the broadcast operator, a service metadata file, additional metadata, commands for accessing encoded content, and additional service information. According to the claimed invention, the transport stream at the output of the multiplexer is preferably an MPEG-2 transport stream and includes at least: linear broadcast channels, the content of which is also used as part of virtual channels; basic and additional metadata of the virtual channel service; if necessary, Linkage descriptor; MPEG-2 transport stream service tables including: PAT program relationship table; RMT program structure tables; CAT conditional access table; NIT network information table; TDT date and time table; BAT table of program groups.

The transmitting part of CAS operates 24/7 offline and supports automatic and manual backup capabilities CAS data using standard means. The keys are stored only in encrypted form, and to encrypt CW and session keys, a specialized hardware device is used - Encryptor, implemented on the basis of a cryptoprocessor, which allows cryptographic operations to be performed in hardware in a secure mode. Only databases with limited access are used to store accounts. Actually, the installation of CAS and the CAS server is carried out on a protected operating system and local network, respectively, with limited access to the CAS software and hardware, which ensures proper control over the security of the encryption subsystem and the operation of the virtual channel service.

The receiving side of the claimed virtual channel service system, according to the presented example implementation (Fig. 4), is equipped with a client device STB 8, made in the form of a digital satellite receiver, equipped with at least a tuner/demodulator 18 that receives the input signal MPEG-2 transport stream , cryptomodule 19, designed to enable decryption of the incoming encrypted transport stream. In one of the embodiments of the claimed invention, the cryptomodule is equipped with a sectional filter of commands for setting the rights of a virtual channel, an EMM message handler corresponding to the virtual channel, with the ability to send commands to set the rights and session keys of the virtual channel. In this case, the crypto module is connected to the main processor CPU 23, which processes data and provides the end user with audio-video output of the content of linear broadcast channels and virtual service channels in the user interface module. In another embodiment, the main processor CPU of the client device is configured to provide the ability to decrypt the incoming encrypted transport stream, through a built-in security system, and perform data processing, providing the end user with audio-video output channel content in the user interface module, wherein the CPU is equipped with a sectional a command filter for setting the rights of a virtual channel, an EMM message handler corresponding to the virtual channel and the ability to send a command to set the rights and session keys of a virtual channel.

The process of encrypting content and generating data for descrambling the encrypted content of the service providing virtual channels actually begins with the process of forming virtual channels of the service, since at this stage the data structure for their encryption and the conditions for their descrambling when using the virtual channel service by the user is laid down. The process of generating virtual channel service content itself is not the subject of the claimed solution and is considered in this example of the feasibility of the invention solely for the purpose of explaining the essence of the claimed solution and achieving the stated technical result by its application. The process of forming virtual service channels is carried out through the sequential execution of the following stages of their formation, transmission and broadcast.

At the first stage of the formation of virtual channels of the service, on the EPG server, equipped with means for generating a schedule of events for the content of linear broadcast channels, in the user interface in a software-hardware manner, through an operator or in automatic mode, a directory of virtual channels is formed, containing at least basic data, including the name of the channel and the position number in the list of channels, as well as additional, but not mandatory, data for each of the channels, for example, a channel logo for displaying it in the user interface module of the client device as an identification feature of the channel, a banner for displaying during technology breaks, for example , intended for its use when there is no broadcast of a linear channel in the virtual channel schedule. The directory of virtual channels is created, stored and edited exclusively on the EPG server. Its adjustment from the client device is not available.

The formation of a selection of events that should be added to the schedule of the generated virtual channels can also be carried out in software and hardware, both manually and automatically. At the same time, as events (transmissions) as units of content of a linear and/or virtual channel, for example, films, advertising blocks, talk shows, cartoons, TV series, sporting events, news, educational and/or educational programs can be accepted, static images, etc. As a scheduling unit, any event is characterized by the date and time of its start and end, as well as a set of metadata indicating the original broadcast channel in the system.

The operator manually generates a selection of virtual channel events in accordance with the selection of hardware and software images of events corresponding to the virtual channel topic specified by the operator, or, for example, based on the results of an analysis of content consumption. According to the provided selection of linear channel transmissions, through the web interface, for the corresponding event, a mark is set for the use of this event as part of a virtual channel and the identifier of a specific virtual channel to the schedule of which the event should be added. In this case, the same event can be marked for adding to the schedule of several scheduled virtual channels. In turn, the automatic formation of a selection does not require the direct participation of the operator; information about the programs is added to the metadata file automatically in software and hardware, based on the results of searching for events in the web interface according to preset criteria. The search is carried out according to the specified parameters in the appropriate form of the EPG server web interface. For example, specific linear channels, event genres, keywords, etc. can be used as parameters for creating a selection of events. After completing the formation of the schedule on the EPG server, the generation of metadata is initiated by selecting the corresponding algorithm pre-installed in the software and hardware in the user interface of the EPG server and based on data pre-installed or manually specified by the operator. The EPG server is equipped with tools for generating, based on the specified algorithm, two types of metadata of virtual service channels: basic metadata and additional metadata, where:

- the main metadata represents the schedule of each of the virtual channels with a directory of virtual channels, where the schedule for each of the virtual channels consists of events broadcast as part of linear broadcast channels, marked in a preset way when forming a selection of virtual channel events.

- additional metadata is graphical data, at least including a technological break banner installed in pauses between adjacent broadcasts of virtual channel events, and a channel logo, etc. additional information perceived in the form of a screensaver or a static image (logo).

In this case, the main metadata at least contains event parameters, including description, start and end times of the event, parameters of the linear broadcast channel in the SNT transport stream (Service ID, Network ID, Transport Stream ID), on which the virtual channel event is broadcast, identifier virtual channel, and parameters of the virtual channels, including the name of the virtual channel, position in the channel list, links to each of the additional metadata files with their binding to the virtual channel, for example, in the form of a "dvb:" URL (see ETSI TS 102 851), that is, links to a specific file in a separately broadcast service.

Technological interruptions in the broadcasting of a virtual channel can be caused, for example, due to the existing time difference between the end of one event (transmission) and the start of broadcasting of the next event (transmission), since these events may belong to different linear broadcast channels, or are spaced apart in time broadcast schedule of one linear channel. The diagram in Fig. 2 shows examples of creating a virtual channel schedule, including setting a technological break mark (Fig. 2a). As follows from the example presented in the diagram of Fig. 2a), event 1 broadcast on a linear channel from 13:00 to 14:00 of one day, event 2 broadcast on a linear channel from 14:30 to 15:00 can be added to the virtual channel schedule the same day. The time interval that occurs between events in the period from 14:00 to 14:30 is marked in the schedule with a technological break (Fig. 2a)). When generating the schedule, the suppression of events by time is also taken into account (Fig. 2a)). When events overlap, the event that starts earlier is added to the schedule. For example (Fig. 2, a)), for one virtual channel the operator marked the events of linear channels from 13:00 to 14:00, from 13:30 to 14:30, while the algorithm preinstalled on the EPG server for generating a schedule of virtual channels and their metadata, will add an event from 13:00 to 14:00 to the schedule of this virtual channel. The next event that can be added to the schedule of this virtual channel must have an event start time only after the end of broadcasting of the first event. In any case, when generating a schedule of virtual channels, during the absence of display of events of linear channels of the generated sample of events for their broadcast within the virtual channel, the algorithm preinstalled in the memory of the EPG server adds a separate event to the schedule of the virtual channel, with the type of technological break. The event type is added by means of pre-installed software and hardware means for generating metadata and scheduling virtual channels of the EPG server, when generating a metadata file in the corresponding parameter, for example, as presented in the example implementation of the claimed invention in Table 1. In this case, as can be seen from the table In example 1, for an event of the “technological break” type, the list of necessary parameters specified in the metadata file differs from the list of necessary parameters of linear channel events broadcast as part of the service’s virtual channels.

A description of the metadata file information parameters and their content in the metadata file is given in the table below.

Table 1.

Description of virtual channel metadata file parameters

As a result of generation, the main metadata is a file in JSON format, the additional metadata is an archive containing all the necessary graphic data files.

When the data of virtual channels changes on the EPG server, for example, when updating the schedule, changing banners, etc., the necessary data is re-generated and subsequently transmitted to the components of the transmitting side in the CAS and to the input of the multiplexer.

The generated metadata is formed in a manner known from the prior art, using the appropriate preinstalled software and hardware of the EPG server, into streams and transmitted to the input of the multiplexing device. The file containing the main metadata of the virtual channel service is transmitted as a data carousel stream (ETSI TR 101 202). An archive containing additional metadata is formed and transmitted as an object carousel stream (ETSI TR 101 202). The carousel method is a mandatory method of broadcasting data in a transport stream to ensure that data is delivered to the client device, taking into account the cyclic repetition of data in the stream.

At the next stage, the generated virtual channel schedule is transferred from the EPG server to the conditional access subsystem C AS.

For subsequent descrambling of linear channels as part of virtual channels, using an algorithm preinstalled on the EPG server in software and hardware, the main metadata (generated schedule of virtual channels) is transmitted to the remote access subsystem, to the CAS server, simultaneously with the transmission of the main metadata to the input multiplexer. The main metadata, as stated earlier, necessarily contains the following information: channel parameters (including SNT parameters of linear channels used as part of the service’s virtual channels), date/time of the start and end of linear channel events.

Based on the data received from the CAS subsystem and the audio-video content arriving at the input of the head equipment subsystem, the SCR scrambler encrypts the content and generates data for broadcast channels and content in the conditional access subsystem C AS (Fig3) corresponding to DVB-Simul crypt standards (ETSI TS 103 197), according to the DVB CSA (Digital Video Broadcasting Common Scrambling Algorithm) algorithm.

The encryption/decryption (scrambling/descrambling) process discussed above in accordance with the stated solution in the general process of organizing a virtual channel service is carried out as follows.

An open (unencrypted) transport stream (TS) is supplied to the input of the encrypting device (scrambler, SCR), which, in addition to additional information, contains audio and video content of linear satellite broadcast channels. The scrambler, using a control word generator (not shown in the diagrams of Fig. 3), implemented in hardware and software, generates control words (CW) used to encrypt the transport stream. The functional component of the CAS server - the EMM message generator (EMMG) (Fig. 3) transmits the generated session key (OrKey, in the diagram of Fig. 3 - sk), used for encryption/decryption of the CW. The scrambler transmits the CW to the CAS server functional component, to the ECM message generator (ECMG) (Fig. 3) for subsequent generation of an ECM message containing encrypted CW control words. In turn, the CW control words are encrypted using session keys to subsequently generate an ECM message containing the encrypted CW control words. The content of the transport stream is encrypted using CW control words and adding ECM messages. Thus, the encryption of the same event broadcast by different channels is carried out with a common control word, encrypted with different session keys for each linear and virtual channel or their group, and the metadata files of the virtual channel service are transmitted to the input of the multiplexer. EMMG generates EMM messages containing service data, access rights information, and specialized commands. The generated EMM messages are also transmitted to the input of the multiplexer, where they form a transport stream by embedding service metadata into the transport stream of the content of linear broadcast channels. As a result, at the output of the multiplexer, in the context of the transmitting part of the conditional access subsystem, an encrypted transport stream is obtained containing ECM and EMM messages in accordance with the DVB standard (ETSI TS 102 470-1), which are transmitted to the input of the client device for receiving and decrypting the secure transport stream at the receiving part satellite broadcasting systems, subject to a valid subscription. So CAS Together with the head equipment, it allows you to manage subscriber access to your services for the implementation of pay television services.

On the client device, decryption of the encrypted content is carried out using a crypto module and a smart card. The smart card stores session keys and access rights recorded by the crypto module after receiving the EMM from the transport stream. At the request of the system, the cryptomodule checks the session key stored on the smart card with a specific ECM message. A positive comparison result confirms the relevance of the session key and its subsequent use to calculate the CW and, as a result, decrypt the encrypted content.

According to the claimed invention, to ensure access to encrypted content only within the virtual channel service, the above-mentioned conditional access system of the claimed solution ensures the following actions:

- processing the list of virtual channels and their schedules.

- generation and storage of a separate set of session keys for access to the encrypted content of virtual channels.

- encryption of CW control words with an additional session key of the virtual channel.

- generation and distribution of EMM with virtual channel session keys.

Restriction of access to content, both linear and virtual channels, can be carried out not only by the time frame of broadcasting the event broadcast on these channels, but also, as stated earlier, by the availability of access rights to view the content, determined by the user’s subscription to the virtual channel service. To take this circumstance into account, according to the stated solution, the transmitting part of the CAS server additionally generates EMM messages with access control commands and session keys for technology packages of virtual channels, ensuring control of subscriber access to the content of the virtual channel service in modes in accordance with data on existing subscriptions received from the billing system. A technological package of virtual channels is understood as a group of channels combined by the operator into packages with different access rights, for example, the “Children’s”, “Sports” package, etc. Such packet aggregation is possible for both linear and virtual channels. Accordingly, access rights to virtual channels within a technology package can be configured both at the channel level as such and at the package level.

However, it is also possible to implement another embodiment of the stated solution, for example, when implementing marketing campaigns, when free access is provided for subscribers who have authorized equipment and activation of the functionality of virtual channels according to the parameters of promotions carried out using virtual channels preset in the system. Thus, the claimed solution makes it possible to provide, within the framework of a virtual channel formed on the transmitting side, without user participation, local access to selected events of a linear broadcast channel if there is a subscription or other authorized access to the virtual channel, regardless of the presence or absence of access rights to the linear channel or a group of linear channels whose events are included in the virtual channel.

After processing the received schedule, the EMM message generator generates a set of session keys for accessing virtual channel events, different from session keys for accessing linear broadcast channels. The control words are additionally encrypted with the generated session keys of the virtual channel. Thus, the same content is scrambled (encrypted) using several session keys: one of which is used to descramble content outside the service, the other is used to descramble the same content when it is played within the virtual channel of the service.

Next, the encrypted data stream for descrambling is transmitted from the CAS subsystem to the input of the multiplexer, where the transmission of EMM messages from the CAS server, necessary for descrambling the events specified in the schedule within the virtual channel, is sequentially checked at two levels: a) availability of access to the virtual channel in accordance with subscription. It is controlled by the EMM with a command to set rights and a session key to access the virtual channel by subscription in accordance with its set duration; b) having access to specified broadcast programs that are included in the virtual channel. It is controlled by inserting into the ECM of a given channel a copy of the CW, encrypted with the session key of the virtual channel only for the duration of the broadcast of the program included in the virtual channel. Sending commands to suspend access to transmission is not required.

The multiplexer is configured to embed data received from the EPG server and subsystem C AS into the TS transport stream. For metadata received from the EPG server, the service broadcast parameters - SNT - are set manually or automatically in software and hardware, for example, through the CAS subsystem interface. For broadcasting metadata, a separate service is allocated as part of the transport stream: for the main metadata and for additional metadata, a separate package (PID) is allocated to simplify the search for the required metadata component.

Since, within the framework of the provided service, the formation of a virtual channel does not require copying the content of a linear broadcast channel and/or any recording of individual events included in the virtual channel in the memory block of the hardware of the transmitting and/or receiving side, and the broadcast of virtual channel events is carried out by organizing limited access to a linear broadcast channel for the period of its broadcast and not has extensions to access to a linear channel outside the framework of an event broadcast simultaneously over linear and virtual channels, metadata broadcasting in one service, according to the considered example implementation, is carried out on only one transponder, which allows the transponder to save capacity used for metadata broadcasting.

To detect a service with metadata, in this case, service information is used with a link to the service with metadata, which is a Linkage descriptor (ETSI EN 300 468 VI .14.1). The Linkage descriptor is added in the graphical interface of the multiplexing device to the stream’s network information table - NIT (Network Information Table, ETSI EN 300 468). The location of the descriptor in the stream is determined by the fact that the NIT table on all transponders of the operator contains the same set of data.

Among the service information contained in the Linkage descriptor, there are metadata broadcast parameters (SNT), service identifier and metadata format version.

An example representation of the Linkage descriptor structure is given below in Table 2

table 2

The Linkage descriptor specifies the following parameters available for editing:

1. Transport Stream ID, Original Network ID, Service ID - metadata file broadcast parameters (SNT).

2. Data Bytes - a string of hexadecimal data containing:

1. signature (four bytes) - service identifier (used directly to match the descriptor with the service),

2. json_format_version - version of the metadata file format (for the ability to update the service without backward compatibility).

Using the Linkage descriptor allows you to create a virtual channel service without user feedback, which provides additional protection for content when it is possible to view it as part of virtual channels.

The transport stream generated in accordance with the claimed invention at the output of the MPEG-2 multiplexer contains at least:

- linear channels, the audio-video content of which will be used as part of virtual channels;

- service with metadata of virtual channels (main and additional metadata); - Linkage descriptor for service discovery with virtual channel metadata;

- MPEG-2 transport stream service tables (according to the EN 300 468 standard), among which are necessarily present:

- RMT (Program Map Table) - program structure table. Included in the stream for each TV program and contains the PID of the TV program components - video, sound, synchronization. In addition, the PMT contains the PID of the ECM message of the conditional access system if the program contains encrypted elementary streams.

- CAT (Condition Access Table) - conditional access table. Contains individual PIDs of all EMM messages.

- NIT (Network Information Table) - network information table. Contains parameters of the data transmission system.

- TDT (Time Data Table) - date and time table. It is a source of reliable time for the client device, allowing you to schedule virtual channels.

- BAT (Bouquet Association Table) - table of program groups. Contains information that allows the client device in this solution to find the corresponding operator channels and related service information.

Next, the TS transport stream arrives at the client device (Fig. 4) of the receiving part of the service. Processing of the TS transport stream and virtual circuit service metadata by the client device is carried out as follows.

The role of the client device, as previously noted, is the digital satellite receiver STB 8, equipped with at least a tuner/demodulator 18 that receives the input signal MPEG-2 transport stream, a cryptomodule 19 C AS module 20, responsible for descrambling the incoming encrypted stream, and the main processor CPU 23, which processes the data and transmits the audio-video signal provided to the end user by the user interface and channel content to the audio-video output (“HDMI”). Also installed in the receiver is a smart card 22 or a built-in emulator of a smart card 21 as part of a cryptomodule 19, then simply a “smart card” containing keys and access rights to content. At the same time, the cryptomodule 19 implements a sectional filter (not shown in the diagram of Fig. 4) for commands to set the rights of a virtual channel, an EMM message type handler corresponding to the virtual channel and sending a command to set rights and a session key of the virtual channel to the smart card. If there are no errors, the operation of the virtual channel service on the STB is carried out by the CPU as follows, where:

- detection of a service with metadata of virtual channels in the transport stream; - filtering and processing ECM and EMM messages with commands for setting rights and session keys for accessing events included in virtual channels, as well as decoding control words for decrypting content events included in virtual channels;

- playback of the content of a virtual channel by automatically switching to a linear broadcast channel that broadcasts the content of the current event according to the schedule of the selected virtual channel, decoding the content of the linear broadcast channel broadcast as part of the selected virtual channel using control words if they are successfully decrypted;

- processing the installation of rights and keys of a virtual channel from a stream; displaying a placeholder banner during technology breaks on a virtual channel.

Discovery of service metadata in the transport stream (Fig. 6) is carried out primarily by the STB CPU by processing the corresponding table in the incoming transport stream (NIT) with the detection of the linkage descriptor and checking its validity. Based on the descriptor of the SNT service parameters available in the linkage, the corresponding metadata is loaded into the TS.

Thanks to the broadcasting of service metadata on each of the incoming signal transponders, the presence of a satellite signal at the STB antenna input is sufficient to form a virtual channel.

After the CPU loads the metadata, the user interface displays the virtual channel with the name, position and logo defined in the metadata and displayed in the corresponding user interface module along with the name of the virtual channel. In the additional user interface module, along with linear channels, the display of a virtual channel schedule is implemented, for familiarization and support of functionality implemented for linear channels.

When the CPU is detected in the incoming transport stream of a new version of the metadata, the metadata is updated on the STB, starting with the download of the metadata.

The operation of the virtual channel service on the client device when interacting with the user (Fig. 7, 8) is carried out as follows.

The operation of the service, after the user has chosen to view a virtual channel, for example, by selecting a channel in the list by pressing a button on the remote control, largely consists of displaying the content of the selected virtual channel (automatic switching according to a schedule) with descrambling of the corresponding content. When choosing to view a virtual channel, CPU STB automatically turns on content according to a schedule: switching to a linear channel according to SNT parameters if the current event is broadcast on a linear channel, or displaying a banner received as part of the metadata if the current event is a technological break. Subsequent operation of the virtual channel service is carried out according to the received schedule: upon completion of the current event, it switches to the SNT of another linear channel if the next event is broadcast on a linear channel, or displays a banner received as part of additional metadata if the next event is a technological break.

After automatic switching (Fig. 7) to a specific linear channel as part of a virtual one, the main processor makes a request to the cryptomodule to descramble the corresponding content. The cryptomodule initiates an appeal to the smart card to decrypt the control word to descramble the content of the virtual channel, configures the elementary streams for the descrambler in accordance with the information in the RMT service table (Program Map Table) to receive ECM messages and sets the CW control words received in the descrambler from a smart card, or through a main processor configured to provide the ability to decrypt an incoming encrypted stream through a built-in security system.

According to the claimed solution, in the virtual channel viewing mode, the CPU of a digital satellite receiver can automatically turn on the broadcast of the content of a linear broadcast channel according to a schedule by switching to a linear broadcast channel according to SNT parameters if the current event is broadcast on a linear broadcast channel, or displaying a banner received as part of the metadata virtual channel if the current event is a technological event.

Thus, the linear channel is descrambled for the duration of the event broadcast when it is played back within the virtual channel service, while the content of the linear channel outside the virtual channel service remains encrypted.

To support this virtual channel model, CAS provides access only for specified TV programs in virtual channel operating mode. Wherein:

1. Access to virtual channel TV programs when viewing the source channel remains closed (in the absence of a valid subscription). That is, all TV programs when watching a regular channel remain unavailable if you do not have a subscription.

2. Subscriptions to source channels do not affect the list of TV programs available in the virtual channel. Only the TV shows specified in the channel schedule remain available in the virtual channel (regardless of the presence of subscriptions to the source channels). 3. Changing the settings of a TV program through a virtual channel automatically affects the CAS access control logic: when adding a TV program to a virtual channel, access is provided in accordance with the broadcast schedule of the TV program (for the duration of the broadcast in the stream). To do this, the ECMG encrypts a copy of the CW broadcast channel using the session key of this virtual channel during the broadcast of the TV program in the virtual channel (Fig. 5). As a result, STB subscribers with a valid subscription to this virtual channel have the technical ability to decrypt CW and open the channel during the broadcast of a TV program.

- when a TV program is deleted from a virtual channel, access is blocked due to the fact that ECMG stops using the session key of the virtual channel when encrypting CW.

- when changing the broadcast schedule of a TV program from a virtual channel, the availability time of the channel content is shifted in accordance with the new start/end time. This is also controlled by ECMG by using the session key of the virtual channel strictly in accordance with the current broadcast schedule of the virtual channel.

4. Support for access control of several virtual channels simultaneously is implemented with the following capabilities:

- include the same broadcast channel in several virtual channels.

2- add several TV programs broadcast at the same time (having overlap) to the virtual channel.

The claimed group of inventions also allows:

1) Expand the list of channel packages without broadcasting multiple copies of channels (which are included in several channel packages).

2) Flexibly and safely limit access to individual TV programs (according to the conditions of copyright holders, rules for distributing content in services, and other restrictions).

3) Provide access to television programs only within a virtual channel. CAS provides access to TV shows within broadcast channels only if you have a valid subscription to the corresponding channel packages.

4) Manage access to virtual channels through subscriptions from the billing system, and in bulk to all authorized devices when activating access to the virtual channel function (all or only specified devices).

Thus, to support complex scenarios for using the system and the method of encrypting descrambling content of the virtual channel service, the CAS subsystem is involved in the following operations of organizing the virtual channel service as follows:

- organization of a virtual channel, including: creation; activation; changing parameters (names); shutdown (temporary suspension); removal . - creating a virtual channel schedule, including: creation; change settings; deletion.

When creating a virtual channel, the CAS server receives a request from the EPG server to create a new virtual channel and checks the values of the virtual channel parameters (external identifier, status, name and description) for correctness. And also, in some cases, it checks the correctness of the external service identifier of the billing system that controls access to this virtual channel. In case of incorrect values, the CAS server returns an error (code and text description of the error) to the EPG server. At the same time, the CAS server stores information about the new virtual channel with reference to the service that controls access (optional) in the CAS database, and also creates in it a new technological package for controlling access to this virtual channel (Fig. 5). Generates and stores in the CAS database the first session key for CW encryption when controlling access to this virtual channel and returns a response to the EPG server with the status of successful creation of the virtual channel.

As a result of successful creation of a virtual channel, the CAS server becomes ready to process commands from the billing system to add, change (start and end dates) and delete subscriptions to this virtual channel, as well as process commands from the EPG server to add, change and delete a broadcast schedule virtual channel and managing access to the virtual channel for subscribers in accordance with billing system subscriptions. Access individually for subscribers under subscriptions from the billing system can be realized using session keys of the technology package that controls access to this virtual channel (Fig. 5).

When switching service channels on the receiving side:

- when switching from a linear channel to a virtual channel, the receiving part of the CAS receives and processes a request from the receiver software to descramble a content event in virtual channel mode. If the subscriber has valid access rights to the CAS technology package for the virtual channel (by subscription at the session key level), and the global availability of the TV program for viewing in the virtual channel (at the CW level), the CW is decrypted and the transport stream descrambling process is initialized (Fig. 5).

- when switching from one virtual channel to another virtual channel, the logic similar to switching a linear channel to a virtual channel is performed.

- when switching from a virtual channel to a regular broadcast (linear) channel, on which the content event added to the virtual channel from which the switch is being broadcast is broadcast, the receiving part of the CAS receives and processes a request from the receiver software to descramble the TV program in regular channel mode. If the subscriber does not have valid access rights to the CAS technology package, it is for a regular broadcast channel that the descrambling, even if you have valid rights to descramble the channel through the virtual circuit.

Thus, to support the functionality of virtual channels, the transmitting part of the CAS implements:

1. Receiving, processing and storing subscriptions to virtual channels from the billing system.

2. Receiving and processing requests for encryption of transport stream (CW) scrambling keys from the head equipment of the broadcast station in accordance with DVB-Simulcrypt standards (ETSI TS 103 197).

3. Receiving, processing and storing a list of virtual channels (and their parameters) from the EPG server.

4. Receiving, processing and storing TV broadcast schedules for virtual channels from the EPG server.

5. Generation, storage, application and automatic scheduled change of session keys of CAS technology packages used to control access to broadcast television programs via a virtual channel.

6. Generating ECM messages taking into account the TV broadcast schedule for virtual channels. To control the fundamental accessibility to individual TV programs via virtual channels (the ability to decrypt CW with a session key issued for access via a virtual channel).

7. Generating EMM messages with access control commands and session keys for technology packages of virtual channels. To control subscriber access to virtual channels in two modes:

- individually in accordance with subscriptions received from the billing system. To provide subscribers with services based on virtual channels through paid subscriptions.

- globally for all subscribers who have authorized equipment and activated the functionality of virtual channels. To optimize the EMM bitrate when carrying out mass marketing campaigns using virtual channels.

At the receiving part of the CAS, as part of the virtual channel service, the encrypted transport stream is descrambled and access to content is controlled as follows:

1. through the CAS Library installed in software and hardware (CAS software (algorithm) integrated into the receiving device (STB) for descrambling channels in accordance with subscriptions) implements:

- filtering and processing of EMM messages with commands for setting rights and session keys for access to TV programs included in virtual channels.

- receiving and processing requests from the receiver software to descramble television programs of virtual channels. - filtering and processing of ECM messages - to receive and decrypt the descrambling keys of television programs (CW) included in the virtual channels. In this case, CW decryption and descrambling of the TV program is performed only when the requested TV program is included in this virtual channel. And also if you have the necessary access rights and session keys (issued by subscription). See Figure 4.

- initialization of descrambling of a given channel using CW in case of successful decryption.

- transmission to the receiver software of information about subscriptions to virtual channel services and the current status of access to them.

2. The software of the built-in or external smart card implements in a secure hardware environment:

- decryption and storage of subscriber rights to access the channel package, as well as session keys if there are valid rights (subscriptions to the channel package).

- decryption and delivery to the CW library for descrambling of a given channel, subject to valid viewing rights.

The modules, blocks and other components have been described above in terms of their features and the functions they provide, together with optional and preferred features. With the information provided and the characteristics and description given, the practical implementation of these features and specific implementation details can be determined by the developer. For example, certain modules could be implemented using software, and some or all components could be implemented using specialized hardware.

The modules and components described above are merely illustrative examples. The invention can be implemented in a variety of ways and, in particular, some components can be integrated with others that perform similar functions, or some components can be omitted in simplified implementations. Hardware and software implementations of each of the described functions can be combined in any combination, both between several components and for each individual component.

It will be appreciated that the functions performed by hardware, computer software, and the like are performed on or using electrical and similar signals. Software implementations may be stored in ROM or may be hardcoded into flash memory.

It is clear that the present invention has been described above using purely illustrative examples of possible embodiments, and various changes in implementation details are possible without departing from the scope of the present invention. Each of the features disclosed in the description and (where appropriate) in the claims and drawings may be implemented either independently or in any suitable combination.

The claimed solution of the group of inventions provides a simple solution for expanding the operational capabilities of a satellite broadcasting system by expanding the capabilities of broadcasting content without increasing the transponder capacity and memory capacity of the transmitting and client parts, while simultaneously increasing the level of content protection by forming virtual channels, the broadcast of content of which does not require prior recording of the content linear broadcast channels, by forming a broadcast schedule for a virtual channel by forming a sample of content events of linear broadcast channels, selected according to criteria preset for each virtual channel and broadcast within the virtual channels of the service sequentially in time and ensuring broadcasting of the content of the virtual channel by securely switching to the one broadcast in in accordance with the virtual channel schedule, the content of linear channels is broadcast at the specified time.

Claims

32

CLAIM

L A system for encrypting the content of a virtual channel service and descrambling it, including at least one formed on the transmitting side, connected to each other and to a multiplexer by communication lines, an EPG server for the electronic program of television programs, equipped with means for generating a schedule of events for the content of linear broadcast channels, and a conditional access subsystem CAS, including an encrypting device equipped with means of encryption and access control to the encrypted content of linear channels, and the multiplexer is equipped with at least means for generating a transport stream of broadcast linear channels, characterized in that the EPG server is additionally equipped with means for generating metadata of virtual channels, and scheduling virtual channels based on the formation of a thematic sampling of content events of linear broadcast channels, selected according to parameters preset for each virtual channel and broadcast within the virtual channels of the service sequentially in time, with the setting for each sampling content event of the identifier of each corresponding virtual channel in the schedule of which it is included a content event and usage flags for each content event within each corresponding virtual channel;

- and the CAS subsystem contains hardware-software transmitting and receiving parts, where the transmitting part includes an SMS subscription management system connected to a billing system, means for generating CW control words with encryption of their session keys, as well as means for generating ECM and EMM messages containing, for each linear and virtual channel of the service or their group, with the establishment of access rights to broadcast the specified virtual channels of the service and linear broadcast channels, and the same content event broadcast by different channels is performed with an encrypted common control word, encrypted with different session keys for each linear and virtual channel or group thereof, and the receiving part is equipped with means for processing EMM and ECM messages to set access rights to each content event, receive and decrypt descrambling keys based on the CW of each content event included in each virtual channel of the service, respectively, and CW-based descrambling facilities.

2. The system according to claim 1, characterized in that the CAS conditional access subsystem is equipped with content encryption means so that the same broadcast event is encrypted with a common control word, which in turn is additionally encrypted with different session keys for each linear and virtual channel or their groups. 33

3. The system according to claim 2, characterized in that the CAS conditional access subsystem is equipped with content encryption tools in accordance with the DVB CSA algorithm.

4. System by and. 1, characterized in that the transport stream at the output of the multiplexer is an MPEG-2 transport stream and includes at least: linear broadcast channels, the content of which is also used as part of virtual channels; basic and additional metadata of the virtual channel service; Linkage handle; MPEG-2 transport stream service tables including: RMT program structure table; CAT conditional access table; NIT network information table; TDT date and time table; BAT table of program groups.

5. The system according to claim 1, characterized in that the metadata of virtual channels is generated with the possibility of broadcasting in one service on one transponder, and is equipped with service information with a link to the service with metadata of virtual channels with the ability to detect the service with metadata in the transport stream.

6. The system according to claim 8, characterized in that the service information is equipped with a Linkage descriptor added to the network information table of the NIT stream, making it possible to provide virtual channel service to the end user without a user feedback channel.

7. The system according to claim 9, characterized in that the service information of the Linkage descriptor includes at least: parameters for broadcasting SNT virtual channel metadata, a service identifier with virtual channel metadata, and a version of the virtual channel metadata format.

8. The system according to claim 1, characterized in that the receiving part includes at least a tuner/demodulator that restores the incoming encrypted transport stream in the input signal modulated by the multiplexer and transmits it to the input of the CAS module cryptomodule, equipped with a system library installed in hardware and software conditional access integrated into the receiving device (STB) for descrambling linear and virtual channels in accordance with subscriptions, providing the ability to descramble the incoming encrypted transport stream and transmit it to the input of the main CPU processor, designed to provide the ability to decrypt the incoming encrypted transport stream, using the built-in a security system implemented in hardware-software, and based on a pre-installed hardware-software algorithm, processing data, providing the end user with audio-video output of the content of channels in the user interface module, while the CPU is equipped with a sectional filter of commands for setting virtual channel rights, an EMM message type handler, corresponding to the virtual channel and the ability to send a command to set the rights and session keys of the service virtual channel.

9. The system according to claim 8, characterized in that the cryptomodule is interfaced with a SmartCard smart card or is equipped with a built-in SmartCard emulator containing keys and access rights to content

10. The system according to any one of claims 1 to 9, characterized in that the transmitting part of the CAS subsystem at least includes means for generating EMM and ECM messages, connected by feedback lines to a means of encrypting CW control words with session keys, and one of the inputs of the ECM message generating means is connected to the output of the EMM message generating means, and the other two inputs are connected via feedback lines to the EPG server and the SCS synchronizer of CW generation processes, the output of which is connected to the MUX multiplexer connected to the transport stream encryption means with C keys U (scrambler) connected to a means for modulating the transport stream and transmitting it to the receiving part, while the second input of the means for generating EMM messages is connected to the SMS subscription management system connected to the billing system.

11. A method for encrypting content and generating data for descrambling a virtual channel service, comprising sequential steps in which at least:

- form, according to preset criteria on the EPG server of the transmitting party, a directory of virtual service channels containing at least the name of the channels and the number of their position in the list of broadcast channels, and a schedule of events of the virtual channels of the service by arranging a selection of content events of linear broadcast channels broadcast within virtual channels of the service sequentially in time and simultaneously with the corresponding broadcast of the linear channel event, setting for each sampling event the identifier of the corresponding virtual channel and marking the use of the event in its composition, with the subsequent generation of metadata for each virtual channel.

- receive and encrypt control words generated by the scrambler of the conditional access subsystem, generate session keys and ECM and EMM messages containing them for linear broadcast channels and virtual channels of the service system, and encryption of the same event broadcast as part of the linear and virtual channels is carried out by a common control word additionally encrypted with various session keys for each linear and virtual channel or their group with setting access rights to broadcast the event specified in the schedule of a linear channel as part of a virtual channel and stopping it at the end of the event, and transmit metadata files of the virtual channel service to the input of the multiplexer, where form a transport stream by embedding service metadata into the transport stream of content of linear broadcast channels and transmit it to the input of the client device.

12 The method according to claim 11, characterized in that the transmitting part of the CAS server additionally generates, stores, uses and automatically updates on a schedule session keys of CAS technology packages used to control access to broadcast events of linear channels through a virtual channel.

13. The method according to claim 11, characterized in that the transmitting part of the CAS server additionally generates EMM messages with access control commands and session keys for technology packages of virtual channels, ensuring control of subscriber access to the content of the virtual channel service in accordance with data on existing subscriptions received from the billing system and/or free access of subscribers who have authorized equipment and activation of the functionality of virtual channels according to parameters preset in the system.

14. The method according to claim 11, characterized in that when forming an MPEG-2 transport stream using a multiplexer, additional service information is built into the transport stream, which is subsequently transmitted to the input of the client device, which is a Linkage descriptor in the network information table (NIT), providing dynamic detection the client device having metadata of the virtual channel service in the transport stream, and at the client device discovering the metadata service in the transport stream through said Linkage descriptor without a user feedback channel.

15. The method according to any of claims 11-14, characterized in that when generating a schedule of virtual channels of the EPG service by the server, when sampling events for a virtual channel broadcast by different linear broadcast channels intersect in time, an event with an earlier broadcast time is added to the schedule, and When events of linear broadcast channels are not displayed, a technological event preset in the service system is added to the virtual channel schedule.

16. A method for descrambling encrypted content of a virtual channel service, comprising stages sequentially carried out by a virtual channel service processing algorithm installed in the receiving part of the CPU in software and hardware, including at least:

- filtering and processing EMM and ECM messages with commands for setting rights and session keys for accessing events included in virtual channels, as well as decoding control words for decrypting content events included in virtual channels; 36

- based on confirmed access rights, playback of the content of a virtual channel by automatically switching to a linear broadcast channel that broadcasts content events according to the schedule of the selected virtual channel, decoding the content of the linear broadcast channel broadcast as part of the selected virtual channel using control words if they are successfully decrypted;

17. The method according to claim 16, characterized in that in the mode of automatic switching to a content event of a linear channel as part of a virtual service channel, the main CPU processor generates in software and hardware a request to the cryptomodule to descramble the corresponding content, and the cryptomodule initiates a call to the smart card or a smart card emulator built into the cryptomodule to decrypt the control word for descrambling the content of the virtual channel and configures the elementary streams for the descrambler in accordance with the information in the RMT service table for receiving ECM messages, and also installs the CW control words received from the smart card into the descrambler cards, providing the ability to decrypt the incoming encrypted stream using a built-in security system.