RU2825320C2 - System and method for managing virtual channel service - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention relates to satellite broadcasting for organizing and creating dedicated "virtual" television channels. Disclosed is a system and a method for controlling a service for providing virtual channels, where CAS subsystem comprises transmitting and receiving parts. Transmitting part includes an SMS subscription management system connected to a billing system which collects and stores actual information on access rights to end user subscriptions; means for generating control words with their session keys encryption; SCR synchronizer of processes of generation of control words, as well as messages ECM and EMM containing them, for each linear and virtual channel of service or their group, with setting of rights of access to broadcast of specified in schedule event of linear channel as part of virtual channel and its suspension at the end of event. Receiving part CAS crypto module is at least equipped with linear and virtual channels descrambling library in accordance with conditional access system subscriptions, to enable descrambling of the incoming encrypted transport stream and its transmission to the input of the main processor (CPU).

EFFECT: broader operational capabilities of the broadcasting system due to broader capabilities of broadcasting content without increasing the amount of memory of the client part, transponder capacity and with simultaneous increase in the level of content protection.

18 cl, 8 dwg

Description

Purpose and scope of application

The group of inventions relates to the field of satellite broadcasting and can find application 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 that the user can switch and display at will (provided that he has the appropriate access rights to each channel). Therefore, the choice of various materials that can be viewed at any given time is very wide, which allows the user to personalize television to a certain extent. However, for most users, keeping track of all the materials offered, classifying them accurately according to their tastes, and scheduling ("programming") the output of programs of interest to them is either too difficult or does not correspond to their inclinations.

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

In the publication US20060156341 (Samsung Electronics Co Ltd, 2005), a solution of a device for generating a virtual channel is disclosed, comprising a virtual channel setting module for setting any one channel of a plurality of channels as a virtual channel per user; and a virtual channel processing module for registering a program selected by the user who has set 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 for any taste can be viewed even if several users use the same television, with minimal manual input required via a remote control or built-in selection buttons of the television.

Publication US20040205815 (Microsoft Technology Licensing LLC) discloses a solution according to which, in an implementation, a virtual channel is associated with each of one or more recorded programs. A virtual channel preview guide is generated for displaying various virtual channels and their associated recorded programs. In the case of selecting a virtual channel, a preview of the recorded program associated with the virtual channel is started. 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 identifier or a virtual channel identifier, which can be selected to start a preview of the recorded program. In addition, the virtual channel preview guide includes a preview for displaying a preview of the recorded program.

From the publication of the patent for invention RU 2541923 (VIAKSESS (FR), 2011) a solution is known for a method for transmitting and receiving multimedia content, according to which the method comprises the steps of: encrypting the control word CWt using a transmitter using a working key and an executable code of the encryption algorithm contained in the virtual motherboard to obtain the cryptogram Enlarged image (opens in a separate window), generating an ECM message (rights management message) containing the cryptogram Enlarged image (opens in a separate window), using the executable code of the syntax designer in the virtual motherboard and transmitting the said ECM message to the end device, receiving the ECM message using the end device, determining the location of the cryptogram Enlarged image (opens in a separate window) in the received ECM message using the executable code of the syntax analyzer and, then, decrypting the cryptogram Enlarged image (opens in a separate window) using the working key and decryption algorithm. This solution is aimed at increasing the security of data transmission due to multi-level encryption. The disadvantages of this solution include limited possibilities of using this solution for individual multimedia objects, without the ability to form a virtual channel based on existing linear channels without increasing the transponder capacity.

The closest to the solution under study is the technology for generating 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 instructions, which are configured by the user, indicate content that should be presented for selection in the virtual channel. Scheduling instructions are executed in order of priority. The virtual channel is filled with content descriptions based on the execution of scheduling instructions. After the virtual channel is initially filled with content, broadcast intervals are determined 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 in the virtual channel.

The disadvantages of the above-mentioned analogs and prototype include the need to increase the transponder capacity used for the formation and use of a virtual channel, 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 complete descrambling of the content reproduced as part of the virtual channel, both as part of the virtual channel and outside it. In addition, the known solutions are built, in most cases, based on the user's preferences, i.e., it is formed on the client device, which complicates the process of forming such an individual channel, and also reduces the protection of the recorded content. Thus, the known solutions for organizing a virtual channel require significant complication of the broadcasting system with a decrease in the level of content protection and an increase in the risk of unauthorized access to the programs of linear broadcasting channels. The limitations of the 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 noticeably increasing technical problems mentioned above, the cost of the solution for the broadcasting operator also increases significantly, incl. due to the need for a significant expansion of transponder capacity (due to the high content bitrate), as well as increased risks of losing control over expensive content (piracy).

The essence of the invention

The present invention is aimed at eliminating the problems inherent in the prior art.

The technical result achieved by the claimed invention is the expansion of the operational capabilities of the broadcasting system, due to the increase in the security of access to the broadcast content of the linear and virtual channels of the service while expanding the capabilities of broadcasting content without increasing the memory capacity of the client (receiving) part, transponder capacity, with a simultaneous increase in the level of content protection.

The claimed technical result is achieved by using a virtual channel service provision management system, which includes at least a transmitting and receiving party, where the transmitting party includes at least an EPG server of an electronic television program guide, connected to each other and to a multiplexer by communication lines, equipped with means for generating a schedule of events for the content of linear broadcast channels, and a conditional access subsystem CAS, which includes a conditional access server and an encryption device, equipped with means for encrypting and providing access to encrypted content of linear channels, and the multiplexer is equipped with means for generating a transport stream, which includes at least the content of linear broadcast channels, a schedule of content events, commands for accessing encrypted content, and the receiving party includes a client device - a digital satellite receiver, equipped with means for receiving, processing transport stream data, and decrypting content, characterized in that it is additionally equipped with means for managing the virtual channel provision service, wherein:

- the CAS subsystem contains transmitting and receiving parts implemented in a software and hardware manner, where the transmitting part includes an SMS subscription management system connected to a billing system implementing the collection and storage of current information on the rights of access to end-user subscriptions; means for generating control words with their encryption by session keys, an SCR synchronizer for the processes of generating control words, as well as ECM and EMM messages containing them, for each linear and virtual channel of the service or their group, with the installation of access rights to the broadcast of a linear channel event specified in the schedule as part of a virtual channel and its suspension upon completion of the event,

- and the CAS module cryptomodule of the receiving part is at least equipped with a software and hardware installed library for descrambling linear and virtual channels in accordance with the subscriptions of the conditional access system, with the provision of the possibility of descrambling the incoming encrypted transport stream and its transmission to the input of the main processor CPU.

In one embodiment of the invention, the receiving part is additionally provided with a smart card (SmartCard), coupled with a crypto module or a built-in smart card emulator (SmartCard emulator) as part of the crypto module, containing keys and access rights to content, coupled with section filters and the main processor CPU via feedback lines.

In one embodiment, the invention includes ECM and EMM message generators, as well as key stores, including smart card keys and session keys, and EMM messages ready for broadcasting in a transport stream.

In one embodiment of the invention, the main processor CPU is provided with software and hardware for detecting service metadata in a transport stream decrypted by means of a cryptomodule and adding virtual service channels in the user interface of the receiving part based on their parameters in the list of linear channels, forming 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 transport stream and reproducing the content of a virtual channel based on them by automatically switching to a linear broadcast channel broadcasting the content of the current event in accordance with the formed schedule of the virtual channel.

In one embodiment of the invention, the conditional access subsystem CAS is provided with content encryption means such 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 group.

In one embodiment of the invention, the conditional access subsystem CAS is provided with means for encrypting content according to the DVB CSA algorithm.

In one embodiment of the invention, the incoming transport stream 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 descriptor; MPEG-2 transport stream service tables including: PMT program structure table; CAT conditional access table; NIT network information table; TDT date and time table; BAT program group table.

In one embodiment of the invention, the service information is provided with a Linkage descriptor added to the network information table of the NIT flow, ensuring the possibility of providing the virtual channel service to the end user without a user feedback channel.

In one embodiment of the invention, the Linkage descriptor service information includes at least: parameters for broadcasting the SNT virtual channel metadata, an identifier of the service with the virtual channel metadata, and a version of the virtual channel metadata format.

In one embodiment of the invention, the invention is distinguished in that the main processor CPU is designed to provide the ability to decrypt the incoming encrypted transport stream, by means of a built-in security system, implemented in a software and hardware manner based on a software and hardware installed algorithm for controlling the descrambling and processing of encrypted transport stream data by means of software and hardware implemented section filters and a library built into the cryptomodule for descrambling linear and virtual channels in accordance with the subscriptions of the conditional access system.

The technical result is also achieved by using a method for managing a service for providing a virtual channel service, which includes sequentially carried out by means of software and hardware installed on the transmitting part of the service, at least:

- generation of initial session key values at the first launch of EMMG, and their storage in the CAS database and transmission to ECMG for encryption of CW control words;

- receiving SMS, processing and storing data on subscriber subscriptions to channel packages from the billing system, including unique subscriber smart card identifiers and channel package identifiers;

- sending SMS requests via EMMG and receiving data on current subscriptions for sending rights and session keys according to subscriptions, requests for encryption of session keys in Encryptor, with subsequent encryption of session keys and their return to EMMG and generation and transmission to the EMM multiplexer of a message that contains the identifier of the CAS technological package used to control access to channels; subscriber access rights to channel packages according to current subscriptions; identifier and value of session keys required for decrypting CW in ECM for descrambling channels:

- EMMG generates new session keys on schedule, saves them in the CAS database and transfers them to ECMG for CW encryption;

- generation of ECMG with transmission to the scrambler of ECM messages upon request from the synchronizing component of the head-end equipment (SCS), where the ECM message contains data directly necessary for descrambling closed channels by the STB equipment: transport stream (CW) descrambling keys encrypted with session keys; identifiers of the session key instance with which copies of the current CW are encrypted; identifier of the CAS technological package, subscription to which determines access rights to viewing channels of the corresponding channel package by means of access to the session key;

- and on the receiving side, detection is carried out in the transport stream of the service with the metadata of virtual channels;

- filtering and processing EMM and ECM messages with commands for setting rights and session keys for access to events included in virtual channels, as well as decryption of control words for decryption of content events included in virtual channels;

- processing of virtual channel metadata, including at least the name of the channels and their position number in the list of broadcast channels, as well as the schedule of events of the service's virtual channels, generated on the transmitting part of the service in the form of a selection of events of the content of the linear broadcast channels, broadcast within the framework of the service's virtual channels sequentially in time and simultaneously with the corresponding broadcast of the linear channel event, with the installation for each event of the selection of the identifier of the corresponding virtual channel and a mark of the use of the event in its composition;

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

- formation of a schedule of virtual channels and its display 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 the virtual channel by automatically switching to a linear broadcast channel that broadcasts the content 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 in the event of their successful decoding.

In one embodiment of the invention, when forming an MPEG-2 transport stream by means of a multiplexer, additional service information is embedded into the transport stream, subsequently transmitted to the input of the client device, which is a Linkage descriptor in the network information table (NIT), ensuring dynamic detection by the client device of the metadata of the virtual channel service in the transport stream, and on the client device, detection of the service with the metadata in the transport stream is carried out by means of the said Linkage descriptor without a user feedback channel.

In one embodiment of the invention, when generating a schedule of virtual channels of the EPG service by the server, when events of the selection broadcast by different linear broadcast channels intersect in time for a virtual channel, an event with an earlier broadcast time is added to the schedule, and for the time when events of the linear broadcast channels are not displayed, a technological event preset in the service system is added to the schedule of the virtual channel.

In one embodiment of the invention, the decryption of the corresponding content after automatic switching to a linear broadcast channel broadcasting a content event as part of a virtual service channel, the configuration of elementary streams of the transport stream for the descrambler in accordance with the information of the PMT service table for receiving ECM messages and the installation of control words in the descrambler are carried out by means of a main processor designed to ensure the possibility of decrypting the incoming encrypted stream by means of a built-in security system.

In one embodiment of the invention, decryption of the encoded content is carried out by means of a cryptomodule and a smart card or a smart card emulator built into the cryptomodule, which ensures storage of OpKey session keys and access rights to virtual service channels and content events, recorded by means of the cryptomodule after receiving an EMM message from the transport stream.

In one embodiment of the invention, descrambling of linear and virtual channels in accordance with subscriptions and with the provision of the possibility of descrambling the incoming encrypted transport stream and its transmission to the input of the main processor CPU is carried out by means of a conditional access system library installed in a software and hardware manner in the cryptomodule, implementing:

- filtering and processing EMM messages with commands for setting rights and session keys for access to events included in virtual channels;

- receiving and processing requests for descrambling virtual channel events generated by the main processor using a pre-installed software algorithm;

- filtering and processing ECM messages to receive and decrypt descrambling keys for events of linear channels included in the virtual channels and in the presence of the necessary access rights and session keys corresponding to the subscription;

- initialization of descrambling of a given virtual channel using CW descrambling keys in case of their successful decryption;

- transmission to the user interface of the receiving part of the service of information about subscriptions to the services of the virtual channel service and the current status of access to them.

In one embodiment of the invention, in the mode of automatic switching to the event of the content of the linear channel as part of the virtual channel of the service, by means of the main processor CPU, a request is generated and sent in a software and hardware manner to the cryptomodule for descrambling the corresponding content, and by means of the cryptomodule, an appeal to the smart card or the smart card emulator built into the cryptomodule is initiated for decrypting the control word for descrambling the content of the virtual channel and the elementary streams for the descrambler are configured in accordance with the information of the service table PMT for receiving ECM messages, and control words CW received from the smart card are installed in the descrambler, ensuring the possibility of decrypting the incoming encrypted stream by means of the built-in security system.

In one embodiment of the invention, the following is carried out by means of a software and hardware algorithm built into a smart card or built into a cryptomodule of a smart card emulator:

- decryption and storage of subscriber rights to access the package of linear and virtual service channels;

- decryption and storage of session keys if there are valid rights to the channel package;

- decoding and output to the CW library for descrambling of a given channel, provided that the viewing rights are valid. It is obvious that both the previous general description and the following detailed description are given only as an example and explanation and are not limitations 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 may be applied to aspects of systems and devices, and vice versa.

Brief description of the drawings

Preferred features of the invention will be described below, solely by way of illustrative examples, with reference to the accompanying graphic figures:

Fig. 1 - generalized diagram of the broadcasting network;

Fig.2 - an example of forming a schedule with the installation of a technological break mark: a) one virtual channel; b) two virtual channels;

Fig.3 - general diagram of the CAS transmitting part;

Fig.4 - generalized diagram of the receiving part of the virtual channel service;

Fig.5 - logic for controlling subscriber access to virtual channels, where SK is a session key; CW _i (SK _i) is the i-th ordinal control word CW _i encrypted with the i-th ordinal session key SK _i ; CP ID is the CAS packet identifier;

Fig.6 - the process of detecting a metadata file;

Fig.7 - operation of the virtual channel service on the receiving part of the virtual channel service;

Fig.8 - switching according to the virtual channel schedule.

It should be noted that the accompanying drawings illustrate only a part of some of the most preferred embodiments of the invention and cannot be considered as limitations of its content, which also includes other embodiments of it.

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.

In the context of the description of an example of the implementation of the claimed solution, the following terms and abbreviations are used:

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

CAS (Conditional Access System) - access restriction system;

CW (Control Word) - control word/control words: a 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 Algorithm) - 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 (audio data, special data) of digital broadcast television;

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

MUX (Multiplexer) – a multiplexer, a device designed to combine several streams of digital television signal data 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 formation of messages granting access rights (EMM) and ECM messages;

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

SMS (Subscriber Management System) - subscriber administration (management) system: a system for recording subscriber information, containing a database of subscribers, subscriber decoders, services subscribed to by subscribers, settlements with subscribers and recording payments received from subscribers;

TS (Transport Stream) - transport stream of digital broadcast television data; TP;

Multiplex - transport stream at the output of a transport multiplexer.

The claimed invention relates to the implementation of the receiving part of the system for providing the virtual channel service. The general solution of the service system, as well as the implementation of its transmitting part, is not the subject of consideration of the present invention and is considered within the framework of the description of the claimed solution for a better understanding of the essence of the claimed group of inventions related to the system for processing the transport stream and metadata of the receiving part of the virtual channel service.

As follows from the example of implementation shown in the diagrams of Figs. 1-8, the system of the service of providing virtual channels to the end user (the virtual channel service) consists of a transmitting 1 (operator) and a receiving 2 (client) side functionally connected to each other (Fig. 1), where the transmitting side includes an electronic television program guide server 4 (EPG server) and a conditional access subsystem 5 CAS (CAS subsystem), connected to each other and to the multiplexer 3 by communication lines, including a conditional access server 6 CAS (CAS Server) and an encryption device 7, in particular, as shown in the diagram of Fig. 1, a scrambler (Scrembler; SCR), equipped with means for encryption and providing access to the encrypted content of the linear channels. The receiving side 2 is a client device - a digital satellite receiver 8 (set-top box, STB), equipped with at least a tuner/demodulator 18 (Tuner/Demodulator), receiving the input signal of the MPEG-2 transport stream and transmitting it after processing to the input of the cryptomodule 19 (CAS module), responsible for descrambling the incoming coded stream, the input of which is connected to the input of the main processor 23 (CPU), which processes data and transmits the audio-video signal, presented to the end user by the user interface and the content of the channels, to the audio-video output. According to the claimed solution, the EPG server input is connected to external control systems, in particular, control of the algorithms for implementing the claimed solution preinstalled in the EPG server memory 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 - to one of the multiplexer inputs. The second input of the CAS subsystem is used to feed audio/video content of the satellite broadcasting system. As noted above, in the generalized implementation scheme of the claimed solution, shown in the diagram in Fig. 1, the CAS 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 (receiving) parts of the virtual channel service provision system is provided by a data transmission channel, which is a satellite signal (Transport Stream; TS), MPEG-2 transport stream (ISO/IEC standard 13818-1, ETSI TS 102 154), formed by the multiplexer of the transmitting side 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 ensure the functional capabilities of the said elements of the virtual channel service system in accordance with the declared solution. The said structural and hardware do not go beyond the generally accepted structural solutions of the said elements of the system. At the same time, their functional capabilities, directly or indirectly, being in the structural or functional unity of the system elements, are regulated by specified software and hardware algorithms pre-installed in the memory of the programmable hardware of the satellite broadcasting system to the end user, controlling the hardware and structural means of the virtual channel service system.

The server of the electronic program guide of television programs EPG (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), initially storing the program schedule for all the operator's channels, and equipped with means for generating a schedule of events of the content of linear broadcast channels, metadata and a schedule of virtual channels of the service. Moreover, the schedule of each of the virtual channels of the service is generated as a composition of a sample of events of the content of linear broadcast channels, selected according to the criteria preset for each virtual channel and broadcast within the virtual channels of the service sequentially by time, with the installation for each event of the sample of the identifier of the corresponding virtual channel and a mark of the use of the event in its composition. To generate the specified sample of events, the EPG server ensures the formation of metadata of virtual channels, including basic data: their name, position in the general list of channels, program schedule, as well as additional data, such as, for example, logos, icons of virtual channels 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 the solution of the virtual channel service, the conditional access subsystem CAS within the framework of the claimed solution consists of a transmitting and receiving part. According to the example of implementing the claimed solution presented in the diagram of Fig. 3, the transmitting part of the CAS interacts with the EPG server 4, the billing system 16, the multiplexer 3, as well as the receiving 2 part of the CAS and the virtual channel service system as a whole, ensuring protection and rules for user access to the content of linear and virtual channels due to encryption and providing access to the 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 subdivided into a server 5 part and a part placed on the head equipment 17. In this case, the server part of the CAS subsystem is connected to the billing 16 system through the SMS subscription management system 13, the output of which is connected to one of the inputs of the EMMG generator 9, intended for generating EMM messages that form the right of access to the content of the linear and virtual channels of the service, the second input of which is connected via feedback lines to the encryptor 14 (Encryptor), intended for encrypting control words CW and session keys. Encryptor 14, in the considered example of implementation, is implemented on the basis of a specialized cryptoprocessor, which allows cryptographic operations to be performed by hardware in a secure mode. The second input of the Encryptor is also connected via feedback lines to the second message generator ECMG 11, intended for forming control ECM 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 to the control word generator 10, the scrambler SCR 7 and the multiplexer MUX 3 of the transport stream (multiplexer), referred to in the diagram of Fig. 3 as the part associated with the head equipment.

Since multiplexer 3 forms 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 generator EMMG 9 and EPG 4 of the server, and the output is connected to the second input of scrambler SCR 7, which ensures encryption of the transport stream with CW keys using the Common Scrambling Algorithm (CSA) algorithm and, in turn, is connected to modulator 15 (Modulator), the output data of which are transmitted to the receiving device.

To implement the tasks of providing the 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 broadcasting system) to decrypt the protected transport stream, provided that there is a valid subscription. Thus, the CAS allows you to manage subscriber access to its services for the implementation of the service. To manage access, the transmitting part of the CAS performs the following actions:

1. At the first launch, EMMG generates initial values of session keys, saves them in the CAS database and transmits them to ECMG for encryption of control words CW (step s1, 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 identifier of a channel package 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.

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

- the date and time of the end of the subscription, used by CAS to control the subscriber's access to viewing a given package of channels.

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

4. The EMMG generator sends requests for encryption of session keys (sk) to the Encryptor, which encrypts them and returns them in encrypted form (sk') to the EMMG (step - s4, Fig. 3), and the EMMG generates and transmits to the multiplexer (MUX) EMM messages (EMMs(sk'), Fig. 3) according to the protocol of the DVB-Simulcrypt standard (ETSI TS 103 197) (step - s5, Fig. 3), which at least contain:

- identifier of the CAS technology package used to control access to channels;

- rights of access of subscribers to channel packages in accordance with current subscriptions;

- identifier and value of session keys required to decrypt CW control words in ECM message for channel descrambling.

5. At the next stage, the EMMG generator generates new session keys (sk) according to the schedule, which it saves in the CAS database and transmits to ECMG for CW encryption in the same way as in step 1 (s1 Fig. 3), starting a new cycle.

6. At the same time, when the scrambler changes the CW at a given interval, usually 10-20 seconds, upon request from the synchronizing component SCS (step s7, Fig. 3), the ECMG generator transmits (step s8, Fig. 3) to the Encryptor the keys (sk) for encrypting the CW, and then the ECMG packs the control words (CW') encrypted with the session keys into ECM messages and returns the ECM message (ECMs(CW'), Fig. 3) to the SCS in response to its request (step s9, Fig. 3) for transmission to the scrambler and MUX (step s10, Fig. 3) messages containing the data directly necessary for descrambling the encrypted channels by the STB equipment:

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

- identifiers of the session key instance (sk) with which copies of the current CW are encrypted;

- identifier of the CAS technology package, the subscription to which determines the access rights to viewing channels of the corresponding channel package through access to the session key.

Thus, the CAS subsystem is equipped with means for 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, whereby 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 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 at the request of the head-end equipment (SCS). In this case, the CW required for decrypting channels from the transport stream on the receiving side are transmitted in encrypted form to the ECM.

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

In accordance with the claimed solution, the multiplexer of the transmitting part is provided with means for forming a transport stream by embedding therein at least the content of the linear broadcast channels, the schedule of content events, and a command for accessing the encrypted content. In this case, the formation of the transport stream (Broadcast Stream) is carried out by embedding into the transport stream the media content received at the input from the broadcast operator, the service metadata file, additional metadata, commands for accessing the 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, a Linkage descriptor; MPEG-2 transport stream service tables including: PAT program relationship table; PMT program structure tables; CAT conditional access table; NIT network information table; TDT date and time table; BAT table of program groups.

The CAS transmitting part operates in a 24-hour autonomous mode and supports automatic and manual backup of CAS data using standard tools. Keys are stored only in encrypted form, and a specialized hardware device, Encryptor, is used to encrypt CW and session keys. It is implemented on the basis of a cryptoprocessor, which allows cryptographic operations to be performed by hardware in a secure mode. Only databases with limited access are used to store accounts. Actually, the CAS and CAS server are installed on a secure 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.

In accordance with the claimed invention, the receiving part (side) of the claimed virtual channel service system, according to the presented example of implementation (Fig. 4), is provided with a client device STB 8, implemented, for example, in the form of a digital satellite receiver, provided with at least a tuner/demodulator 18, receiving an input signal MPEG-2 transport stream, a cryptomodule 19, implemented with the possibility of decrypting the incoming encrypted transport stream. In one of the embodiments of the claimed invention, the cryptomodule is provided with a section filter for commands for setting the rights of the virtual channel, a processor of EMM messages corresponding to the virtual channel, with the possibility of sending a command for setting the rights and session keys of the virtual channel. In this case, the cryptomodule is connected to the main processor CPU 23, which processes data, providing the end user with the content of the linear broadcast channels and virtual service channels in the user interface module to the audio-video output. In another embodiment, the main processor CPU of the client device is designed to provide the ability to decrypt the incoming encrypted transport stream, by means of a built-in security system, and to process data, providing the end user with the audio-video output of the content of the channels in the user interface module, while the CPU is equipped with a section filter for commands for setting the rights of the virtual channel, a handler for EMM messages corresponding to the virtual channel and the ability to send a command for setting the rights and session keys of the virtual channel.

The process of encryption of content and generation of data for descrambling of encrypted content of the service of provision of virtual channels actually begins with the process of formation of virtual channels of the service, since at this stage the structure of data for their encryption and conditions of their descrambling when using the service of virtual channels by the user is laid down. The process of formation of content of the service of virtual channels itself is also not the subject of the claimed solution and is considered in this example of feasibility of the invention solely for the purpose of explaining the essence of the claimed solution and achievement of the claimed 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 broadcasting.

At the first stage of forming the virtual channels of the service, on the EPG server, equipped with the means of forming the schedule of events of the content of the linear channels of broadcasting, in the user interface in a software and hardware way, by means of the operator or in automatic mode, a directory of virtual channels is formed, containing at least the 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, the channel logo for displaying it in the module of the user interface of the client device as an identification feature of the channel, a banner for displaying during technological breaks, for example, intended for its use when the schedule of the virtual channel does not include the broadcast of the linear channel. The directory of virtual channels is created, stored and edited exclusively on the EPG server. Its correction from the client device is not available.

Formation of a selection of events that should be added to the schedule of the virtual channels being formed can also be implemented in a software and hardware manner, both manually and automatically. In this case, as events (programs) as a unit of content of a linear and/or virtual channel, for example, films, advertising blocks, talk shows, cartoons, series, sports events, news, educational and/or training programs, static images, etc. can be accepted. As a unit of the schedule, any event is characterized by the date and time of its beginning 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 events by the software and hardware image that correspond to the virtual channel topic specified by the operator, or, for example, based on the results of content consumption analysis. According to the provided selection of linear channel programs, a mark of the use of this event as part of the virtual channel and the identifier of a specific virtual channel, to the schedule of which the event should be added, are set for the corresponding event via the web interface. In this case, the same event can be marked for adding to the schedule of several planned virtual channels. In turn, automatic generation of a selection does not require the direct participation of the operator, information about the programs is added to the metadata file by the software and hardware image automatically, based on the results of the event search in the web interface using preset criteria. The search is performed by the specified parameters in the corresponding form of the EPG server web interface. For example, specific linear channels, event genres, keywords, etc. can be used as parameters for generating a selection of events.

After the schedule formation is completed, the EPG server initiates the generation of metadata by selecting the corresponding pre-installed software and hardware algorithm in the EPG server user interface and based on the data pre-installed or specified manually by the operator. The EPG server is equipped with the means of generating, based on the specified algorithm, two types of service virtual channel metadata: basic metadata and additional metadata, where:

- the main metadata is 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 the linear broadcast channels, marked in a predetermined manner when forming a selection of events for the virtual channel.

- additional metadata are graphic 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 splash screen or static image (logo).

In this case, the main metadata, at least, contain the parameters of the events, including the description, the start and end time of the event, the 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, the identifier of the virtual channel, and the parameters of the virtual channels, including the name of the virtual channel, the position in the list of channels, links to each of the additional metadata files with their binding to the virtual channel, for example, in the form of "dvb:" URL (see ETSI TS 102 851), that is, links to a specific file in a separately broadcast service.

Technological breaks in the broadcasting of a virtual channel may be caused, for example, by the existing time difference between the end of one event (program) and the beginning of the broadcasting of the event (program) following it, since the said events may belong to different linear broadcasting channels or are spaced out in time in the broadcasting schedule of one linear channel. The diagram in Fig. 2 shows examples of forming a virtual channel schedule, including with the installation of a technological break mark (Fig. 2a). As follows from the example shown in the diagram in Fig. 2a), event 1 broadcast on the linear channel from 13:00 to 14:00 of one day, event 2 broadcast on the linear channel from 14:30 to 15:00 of the same day can be added to the virtual channel schedule. The time interval between events from 14:00 to 14:30 is marked in the schedule with a technological break (Fig. 2a). When generating the schedule, time intersections of events are also taken into account (Fig. 2a). When events intersect, the event that starts earlier is added to the schedule. For example (Fig. 2a), for one virtual channel the operator has marked events of linear channels from 13:00 to 14:00, from 13:30 to 14:30, while the algorithm for generating the schedule of virtual channels and their metadata pre-installed on the EPG server will add the 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 the start time of the event following only after the end of the broadcast of the first event. In any case, when generating the schedule of virtual channels, for the time of absence of display of events of linear channels of the generated sample of events for their broadcasting within the virtual channel, the algorithm preset 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 preset software hardware means of forming metadata and schedule of virtual channels of the EPG server, when generating the metadata file in the corresponding parameter. In this case, for the event of the type "technological break" the list of necessary parameters specified in the metadata file will differ from the list of necessary parameters of events of linear channels broadcast as part of the virtual channels of the service.

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

When changing the data of virtual channels on the EPG server, for example, when updating the schedule, changing banners, etc., the necessary data is re-generated and then transferred 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, 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 (Data carousel, ETSI TR 101 202). The archive containing additional metadata is formed and transmitted as an object carousel stream (Object carousel, ETSI TR 101 202). The carousel method is a mandatory method of broadcasting data in a transport stream to ensure the guarantee of data delivery to the client device, taking into account the cyclic repetition of data in the stream.

At the next stage, the generated schedule of virtual channels is transferred from the EPG server to the conditional access subsystem CAS.

For subsequent descrambling of linear channels as part of virtual channels, using the algorithm pre-installed on the EPG server in a software and hardware manner, the main metadata (generated schedule of virtual channels) are transmitted to the remote access subsystem, to the CAS server, simultaneously with the transmission of the main metadata to the input of the multiplexer. The main metadata, as indicated earlier, necessarily contain the following information: channel parameters (including SNT parameters of linear channels used as part of the virtual channels of the service), date/time of the beginning and end of events of linear channels.

Based on the data received from the CAS subsystem and the audio-video content arriving at the input of the head equipment subsystem, the content is encrypted and the data of the broadcast channels and content is generated in the CAS conditional access subsystem (Fig. 3) corresponding to the DVB-Simulcrypt standards (ETSI TS 103 197), according to the DVB CSA (Digital Video Broadcasting Common Scrambling Algorithm) algorithm, using the SCR scrambler.

The above-considered process of encryption/decryption (scrambling/descrambling) in the general process of organizing the virtual channel service is carried out as follows.

An open (unencrypted) transport stream (TS) is fed to the input of the encryption device (scrambler, SCR), which, in addition to additional information, contains audio and video content of linear satellite broadcasting channels. The scrambler, by means of a control word generator (not shown in the diagrams in Fig. 3), implemented in a software and hardware manner, generates control words (CW) used for encryption of the transport stream. The functional component of the CAS server – the EMM message generator (EMMG) (Fig. 3) transmits the generated session key (OpKey, in the diagram in Fig. 3 – sk), used for encryption/decryption of the CW. The scrambler transmits the CW to the functional component of the CAS server, to the ECM message generator (ECMG) (Fig. 3) for subsequent generation of the ECM message containing the encrypted CW control words. In turn, the CW control words are encrypted using the session keys for subsequent generation of the ECM message containing the encrypted CW control words. The transport stream content is encrypted using CW control words and adding ECM messages. Thus, encryption of the same event broadcast by different channels is performed by a common control word encrypted with different session keys for each linear and virtual channel or their group, and the virtual channel service metadata files are transmitted to the input of the multiplexer. EMMG generates EMM messages containing service data, information on access rights and specialized commands. The generated EMM messages are also transmitted to the input of the multiplexer, where the transport stream is formed by embedding the service metadata into the transport stream of the linear broadcast channel content. 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 according to the DVB standard (ETSI TS 102 470-1), which are transmitted to the input of the client device for receiving and decrypting the protected transport stream on the receiving part of the satellite broadcasting system, subject to the presence of a valid subscription. Thus, CAS, together with the head-end equipment, allows managing subscriber access to its services for the implementation of pay television services.

According to the claimed invention, the decoding of the coded content is performed on the client device by means of a crypto module and a smart card. The smart card stores session keys and access rights recorded by means of the crypto module after receiving the EMM from the transport stream. At the system request, the crypto module checks the session key stored on the smart card with a certain ECM message. A positive comparison result confirms the relevance of the session key and its subsequent use for calculating the CW and, as a consequence, decoding the coded content.

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

- processing the list of virtual channels and their schedule;

- 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.

Access to the content of both linear and virtual channels can be restricted not only by the time frames of the broadcast of the event transmitted via these channels, but also, as indicated earlier, by the availability of access rights to view the content determined by the subscription of the user of the virtual channel service. To take this circumstance into account, the transmitting part of the CAS server additionally generates EMM messages with access control commands and session keys for technological packages of virtual channels with the provision of subscriber access control to the content of the virtual channel service in modes in accordance with the data on current subscriptions received from the billing system. A technological package of virtual channels is understood to be a group of channels combined by the operator into packages with different access rights, for example, the package "Children's", "Sports", etc. Such package unification is possible for both linear and virtual channels. Accordingly, access rights to virtual channels within the framework of a technological package can be configured both at the level of the channel as such and at the level of the package.

However, it is possible to implement another version of the declared solution, for example, when implementing marketing campaigns, when free access is provided to subscribers who have authorized equipment and activation of the functionality of virtual channels according to the parameters of campaigns pre-set in the system, carried out using virtual channels.

Thus, the claimed solution allows for local access to selected events of a linear broadcast channel within the framework of a virtual channel formed on the transmitting side, without the participation of users, in the presence of a subscription or other authorized access to the virtual channel, regardless of the presence or absence of access rights to the linear channel or group of linear channels, the events of which are included in the virtual channel.

After processing the received schedule, the EMM message generator generates a set of session keys for access to virtual channel events, different from the session keys for access to linear broadcast channels. 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 is transmitted for descrambling from the CAS subsystem to the input of the multiplexer, where the data received from the EPG server and the CAS subsystem are configured to be embedded in the TS transport stream. For metadata received from the EPG server, the service broadcast parameters – SNT are set manually or automatically in a hardware-software manner, for example, via the CAS subsystem interface. A separate service is allocated as part of the transport stream for metadata broadcasting: a separate packet (PID) is allocated for the main metadata and for additional metadata 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 the linear broadcast channel and/or any recording of individual events included in the virtual channel in the memory unit of the hardware of the transmitting and/or receiving party, and the broadcasting of events of the virtual channel is carried out by organizing limited access to the linear broadcast channel for the period of its broadcasting and does not extend to access to the linear channel outside the framework of an event broadcast simultaneously on the linear and virtual channels, the broadcasting of metadata in one service, according to the example of implementation under consideration, is carried out only on one transponder, which allows the transponder to save the capacity used for broadcasting metadata, without increasing the memory volume of the client (receiving) part with a simultaneous increase in the level of content protection and the implementation of the virtual channel service.

In this case, service information with a link to the service with metadata is used to detect the service with metadata, which is a Linkage descriptor (ETSI EN 300 468 V1.14.1). The Linkage descriptor is added to the flow network information table - NIT (Network Information Table, ETSI EN 300 468) in the graphical interface of the multiplexing device. The location of the descriptor in the flow is determined by the fact that the NIT table on all the operator's transponders contains the same set of data.

The service information contained in the Linkage descriptor includes 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

Original Network ID 263 Transport Stream ID 601 Service ID 123 Linkage type 0x82 Data Bytes 56 5f 43 68 00 00 00 01

The following parameters are set in the Linkage descriptor and are available for editing:

1. Transport Stream ID, Original Network ID, Service ID - parameters for broadcasting the metadata file (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 (to enable service updates 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 implementing the ability to view it as part of virtual channels.

Thus, the transport stream formed 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 virtual channel metadata (basic and additional metadata);

- Linkage descriptor for service discovery with virtual channel metadata;

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

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

- 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) – a table of date and time. It is a source of reliable time for the client device, allowing to create a schedule of virtual channels.

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

The transport stream TS generated in the above manner in the virtual channel service system arrives at the client device (Fig. 4) of the receiving part of the service, where, by means of the system for processing the transport stream of the virtual channel service metadata, its final processing is carried out in accordance with the claimed invention for subsequent presentation to the user. The processing of the transport stream TS and the virtual channel service metadata at the receiving part of the service is carried out as follows.

As previously noted, the digital satellite receiver STB 8 is used as the client device in the embodiment under consideration, equipped with at least a tuner/demodulator 18 ("Tuner/Demodulator"), receiving the input signal MPEG-2 transport stream, a cryptomodule 19 of a CAS module 20 ("CAS module"), responsible for descrambling the incoming encrypted stream and a main processor CPU 23, processing data and transmitting an audio-video signal, provided to the end user by the user interface and channel content, to the audio-video output ("HDMI"). Also, a smart card 22 ("SmartCard") or a built-in smart card emulator 21 ("SmartCard emulator") as part of the cryptomodule 19, hereinafter simply "smart card", containing keys and access rights to the content, is preferably installed in the receiver. In this case, the receiving part is equipped with the following, coupled with the cryptomodule 19, for example, implemented (built-in) in it, and the main processor CPU 23, implemented in a software and hardware manner (not shown in the diagram in Fig. 4):

- a section filter in EMM messages of the transport flow of commands for setting rights and session keys for access to each virtual channel of the subscription service,

- a means of detecting and descrambling in ECM messages of the transport stream copies of the CW descrambling keys of each included in the virtual transmission channel of the linear broadcast channel, encrypted with the session key of the virtual channel for the duration of the broadcast of the linear channel as part of the virtual service channel.

As a result of processing by the implemented section filters of EMM messages, a command for setting rights and a session key for each virtual channel of the service are sent to the smart card via the crypto module. In the absence of errors, the operation of the virtual channel service on the STB is carried out by the CPU as follows, where the following is carried out:

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

- filtering and processing of ECM and EMM messages with commands for setting rights and session keys for access to events included in virtual channels, as well as decryption of control words for decryption of content events included in virtual channels;

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

- formation of a schedule of virtual channels and its display in the corresponding user interface module;

- reproduction 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 in the event of their successful decoding;

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

- display of a placeholder banner during technological breaks on a virtual channel.

The use of the receiving part of the service, as part of the processing system of the transport stream and metadata generated on the transmitting part of the service, coupled with the cryptomodule of the smart card (external smart card) or the smart card emulator built into the cryptomodule, allows, by means of the built-in software and hardware algorithm, to implement:

- decryption and storage of subscriber rights to access the package of linear and virtual service channels;

- decryption and storage of session keys if there are valid rights to the channel package;

- decoding and output to the CW library for descrambling of a given channel if there are valid viewing rights.

This ensures secure storage of keys without additional load on the receiving system, and also increases the reliability of using the virtual channel service.

In this case, in a preferred embodiment of the claimed invention, the cryptomodule of the receiving part of the service can also be equipped with a software and hardware installed library of the conditional access system, implementing:

- filtering and processing EMM messages with commands for setting rights and session keys for access to events included in virtual channels;

- receiving and processing requests for descrambling virtual channel events generated by the main processor using a pre-installed software algorithm;

- filtering and processing ECM messages to receive and decrypt descrambling keys for events of linear channels included in the virtual channels and in the presence of the necessary access rights and session keys corresponding to the subscription;

- initialization of descrambling of a given virtual channel using CW descrambling keys in case of their successful decryption;

- transfer to the user interface of the receiving part of the service of information about subscriptions to the services of the virtual channel service and the current status of access to them

Descrambling of linear and virtual channels in accordance with subscriptions and with the provision of the ability to descramble the incoming encrypted transport stream and transmit it to the input of the main CPU, controlled in this way by means of the conditional access system library, also increases the security of using the service and the relevance of processing access data to the service channels and the content broadcast by them.

The detection of service metadata in the transport stream (Fig. 6) is primarily performed by the STB CPU by processing the corresponding table in the incoming transport stream (NIT) with detection of the linkage descriptor and checking its validity. According to the SNT service parameters in the linkage descriptor, the corresponding metadata are 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 loading the CPU 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 virtual channel name. In the additional user interface module, along with the linear channels, the virtual channel schedule is displayed for review and with support for the functionality implemented for the linear channels.

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

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 selected to view a virtual channel, for example, by selecting a channel in the list by pressing a button on the remote control, mostly consists of displaying the content of the selected virtual channel (automatic switching according to the schedule) with descrambling of the corresponding content.

When selecting viewing of a virtual channel, the CPU STB automatically switches on the content according to the schedule: switching to a linear channel according to the 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, switching to the SNT of another linear channel is carried out if the next event is broadcast on a linear channel, or displaying a banner received as part of additional metadata if the next event is a technological break.

After automatic switching (Fig. 7) to a certain linear channel within the virtual channel, 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 for descrambling the content of the virtual channel, configures the elementary streams for the descrambler in accordance with the information in the PMT service table (Program Map Table) to receive ECM messages and installs the CW control words received from the smart card or by means of the main processor, which is designed to ensure the ability to decrypt the incoming encrypted stream by means of the built-in security system.

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

This results in the linear channel being descrambled for the duration of the event broadcast when it is played within the virtual channel service, while the linear channel content outside the virtual channel service remains encrypted.

To support this virtual channel model, CAS provides access only to specified TV programs in the virtual channel mode. In this case:

1. Access to the virtual channel's TV programs remains closed when viewing the source channel (if there is no active subscription). That is, all TV programs remain unavailable when viewing a regular channel if there is no subscription.

2. Subscriptions to source channels do not affect the list of TV programs available in the virtual channel. Only TV programs specified in the channel schedule remain available in the virtual channel (regardless of subscriptions to source channels).

3. Changing the TV program settings via 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 TV program broadcast schedule (for the duration of the stream broadcast). For this purpose, ECMG encrypts a copy of the CW of the broadcast channel using the session key of this virtual channel for the duration of the TV program broadcast in the virtual channel (Fig. 5). As a result, STB subscribers with an active subscription to this virtual channel have the technical ability to decrypt the CW and open the channel during the broadcast of the TV program.

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

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

- add several TV programs broadcast at the same time (with overlapping) to a 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 restrict access to individual TV programs (according to the terms of copyright holders, rules for distributing content in services, and other restrictions).

3) Provide access to TV programs only within the virtual channel. CAS provides access to TV programs within the broadcast channels only if there is a valid subscription to the corresponding channel packages.

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

Thus, in order to support complex scenarios of using the system and the method of encryption of descrambling of the content of the virtual channel service, the CAS subsystem participates in the following operations of organizing the virtual channel service as follows:

- organization of a virtual channel, including: creation; activation; changing parameters (name); disabling (temporary suspension); deletion,

- formation of a virtual channel schedule, including: creation; changing parameters; 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 virtual channel parameter values (external identifier, status, name and description) for correctness. And also, in some cases, checks the correctness of the external identifier value of the billing system service that controls access to this virtual channel. In case of incorrect values, the CAS server returns an error to the EPG server (code and text description of the error). In this case, the CAS server saves information about the new virtual channel with a link to the service that controls access (optional) in the CAS database, and also creates a new technological package in it for managing access to this virtual channel (Fig. 5). Generates and saves in the CAS database the first session key for CW encryption when managing access to this virtual channel and returns to the EPG server a response 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 to process commands from the EPG server to add, change and delete the broadcast schedule of the virtual channel and to manage access to the virtual channel for subscribers in accordance with the subscriptions of the billing system. Access individually for subscribers by subscriptions from the billing system can be implemented using session keys of the technological package that manages 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 CAS receiving part receives and processes a request from the receiver software to descramble the content event in the virtual channel mode. If the subscriber has valid access rights to the CAS technological package for the virtual channel (by subscription at the session key level), and the TV program is globally available 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 is similar to switching a linear channel to a virtual channel.

- when switching from a virtual channel to a regular broadcast (linear) channel, on which a content event added to the virtual channel from which switching is performed is broadcast, the CAS receiving part receives and processes a request from the receiver software to descramble the TV program in the regular channel mode. If the subscriber does not have valid access rights to the CAS technological package specifically for the regular broadcast channel, descrambling is refused, even if there are valid rights to descramble the channel through the virtual channel.

Thus, to support the functionality of virtual channels, the transmitting part of 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 headend equipment of the broadcasting 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 technological packages used to control access to broadcast television programs via a virtual channel.

6. Generating ECM messages taking into account the broadcast schedule of TV programs for virtual channels. For managing 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 technological packages of virtual channels. To control subscriber access to virtual channels in two modes:

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

- globally for all subscribers with authorized equipment and activation of virtual channel functionality. To optimize the EMM bitrate when conducting mass marketing campaigns using virtual channels.

At the receiving end of the CAS, within the virtual channel service, descrambling of the encrypted transport stream and control of access to the content is performed as follows:

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

- filtering and processing 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 for descrambling TV broadcasts of virtual channels.

- filtering and processing of ECM messages - to receive and decrypt the keys for descrambling TV programs (CW) included in the virtual channels. In this case, decryption of CW and descrambling of a TV program is performed only when the requested TV program is included in this virtual channel. And also in the presence of the necessary access rights and session keys (issued by subscription). See Fig. 4.

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

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

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 a channel package, as well as session keys if there are valid rights (subscriptions to a channel package).

- decoding and output to the CW library for descrambling of a given channel if there are valid viewing rights.

This results in the linear channel being descrambled for the duration of the event broadcast when it is played within the virtual channel service, while the linear channel content outside the virtual channel service remains encrypted.

To support this virtual channel model, CAS provides access only to specified TV programs in the virtual channel mode. In this case:

1. Access to the content of the virtual channel remains closed when viewing the source channel (if there is no active subscription). That is, all TV programs remain unavailable when viewing a regular channel if there is no subscription.

2. Subscriptions to source channels do not affect the list of TV programs available in the virtual channel. Only TV programs specified in the channel schedule remain available in the virtual channel (regardless of subscriptions to source channels).

3. Changing the TV program settings via 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 TV program broadcast schedule (for the duration of the stream broadcast). For this purpose, ECMG encrypts a copy of the CW of the broadcast channel using the session key of this virtual channel for the duration of the TV program broadcast in the virtual channel (Fig. 5). As a result, STB subscribers with an active subscription to this virtual channel have the technical ability to decrypt the CW and open the channel during the broadcast of the TV program.

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

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

- add several TV programs broadcast at the same time (with overlapping) to a 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 restrict access to individual TV programs (according to the terms of copyright holders, rules for distributing content in services, and other restrictions).

3) Provide access to TV programs only within the virtual channel. CAS provides access to TV programs within the broadcast channels only if there is a valid subscription to the corresponding channel packages.

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

The modules, units, 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 descriptions given, the practical implementation of these features and the specific implementation details can be determined by the developer. For example, certain modules could be implemented using software, and some or all of the components could be implemented using specialized hardware.

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

It is understood 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 "hardwired" into flash memory.

It is obvious that the present invention has been described above using only illustrative examples of possible embodiments of its implementation, and various changes in the details of implementation are possible without leaving the scope of the present invention.

Each of the features disclosed in the description and (where appropriate) in the claims and graphic figures 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, due to expanding the capabilities of broadcasting content without increasing the memory capacity of the client part of the service, transponder capacity and with a simultaneous increase in the level of content protection by forming virtual channels, the broadcasting of the content of which does not require preliminary recording of the content of the linear broadcasting channels, as well as due to a secure process of forming virtual channels of the service on the receiving part and providing access to them and the content of the linear channel broadcast within each of them corresponding to the schedule with multi-level access control, ensuring switching to the content of the linear channels broadcast in accordance with the schedule of the virtual channel only at the broadcasting time specified for each content event within the linear channel.

Claims (40)

1. A system for managing the service of providing a virtual channel service, including at least a transmitting and receiving side, where the transmitting side includes at least an EPG server of an electronic television program guide, connected to each other and to a multiplexer by communication lines, equipped with means for generating a schedule of events of the content of linear broadcast channels, and a conditional access subsystem CAS, including a conditional access server and an encryption device, equipped with means for encryption and providing access to encrypted content of linear channels, and the multiplexer is equipped with means for generating a transport stream, including at least the content of linear broadcast channels, schedules of content events, commands for access to encrypted content, and the receiving side includes a client device - a digital satellite receiver, equipped with means for receiving, processing transport stream data and decrypting content, characterized in that it is additionally equipped with means for managing the service of providing virtual channels, wherein: - the CAS subsystem contains a transmitting and receiving part implemented in a software and hardware manner, where the transmitting part includes an SMS subscription management system connected to a billing system implementing the collection and storage of current information on the rights of access to end-user subscriptions; means for generating control words with their encryption by session keys, an SCS synchronizer for the processes of generating control words, as well as ECM and EMM messages containing them, for each linear and virtual channel of the service or their group, with the installation of access rights to the broadcast of a linear channel event specified in the schedule as part of a virtual channel and its suspension upon completion of the event, - and the CAS module cryptomodule of the receiving part is at least equipped with a software and hardware installed library for descrambling linear and virtual channels in accordance with the subscriptions of the conditional access system, with the provision of the possibility of descrambling the incoming encrypted transport stream and its transmission to the input of the main processor CPU. 2. The system according to item 1, characterized in that the receiving part is additionally equipped with a smart card (SmartCard), coupled with a cryptomodule or a built-in smart card emulator (SmartCard emulator) as part of the cryptomodule, containing keys and access rights to content, coupled with section filters and the main processor CPU via feedback lines. 3. The system according to item 2, characterized in that it includes ECM and EMM message generators, as well as key storage, including smart card keys, and session keys, and EMM messages ready for broadcasting in the transport stream. 4. The system according to item 1, characterized in that the main processor CPU is equipped with software and hardware for detecting service metadata in the transport stream decrypted by means of the cryptomodule and adding virtual channels of the service in the user interface of the receiving part based on their parameters in the list of linear channels, forming a schedule of virtual channels and displaying it in the corresponding module of the user interface, processing the installation of rights and keys of the virtual channel from the transport stream and reproducing the content of the virtual channel based on them by automatically switching to the linear channel of broadcasting the content of the current event in accordance with the formed schedule of the virtual channel. 5. The system according to item 1, characterized in that the conditional access subsystem CAS is equipped with means for encrypting content 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 group. 6. The system according to item 2, characterized in that the conditional access subsystem CAS is equipped with means for encrypting content according to the DVB CSA algorithm. 7. The system according to claim 1, characterized in that the incoming transport stream 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 descriptor; MPEG-2 transport stream service tables including: PMT program structure table; CAT conditional access table; NIT network information table; TDT date and time table; BAT program group table. 8. The system according to item 3, characterized in that the service information is provided with a Linkage descriptor added to the network information table of the NIT flow, ensuring the possibility of providing the virtual channel service to the end user without a user feedback channel. 9. The system according to item 4, characterized in that the Linkage descriptor service information includes, at least: parameters for broadcasting the metadata of the SNT virtual channels, an identifier of the service with the metadata of the virtual channels, and a version of the format of the metadata of the virtual channels. 10. A system according to any one of paragraphs 1-9, characterized in that the main processor CPU is designed to provide the ability to decrypt the incoming encrypted transport stream by means of a built-in security system implemented in a software and hardware manner based on an installed software and hardware algorithm for controlling descrambling and processing of encrypted transport stream data by means of software and hardware implemented section filters and a library built into the cryptomodule for descrambling linear and virtual channels in accordance with the subscriptions of the conditional access system. 11. A method for managing the service of providing a virtual channel service, which includes sequentially carried out by means of software and hardware installed on the transmitting part of the service, at least: - generation of initial session key values at the first launch of EMMG and their storage in the CAS database and transmission to ECMG for encryption of CW control words; - receiving SMS, processing and storing data on subscriber subscriptions to channel packages from the billing system, including unique subscriber smart card identifiers and channel package identifiers; - sending SMS requests via EMMG and receiving data on current subscriptions for sending rights and session keys according to subscriptions, requests for encryption of session keys in Encryptor, with subsequent encryption of session keys and their return to EMMG and generation and transmission to the EMM multiplexer of messages that contain the identifier of the CAS technological package used for channel access control; subscriber access rights to channel packages according to current subscriptions; identifier and value of session keys required for decryption of CW in ECM for channel descrambling; - EMMG generates new session keys on a schedule, saves them in the CAS database and transfers them to ECMG for CW encryption; - generation of ECMG with transmission to the scrambler of ECM messages upon request from the synchronizing component of the head-end equipment (SCS), where the ECM message contains data directly necessary for descrambling closed channels by the STB equipment: transport stream (CW) descrambling keys encrypted with session keys; identifiers of the instance of the session key with which copies of the current CW are encrypted; identifier of the CAS technological package, subscription to which determines access rights to viewing channels of the corresponding channel package by means of access to the session key, and on the receiving side, detection is carried out in the transport stream of the service with the metadata of virtual channels; - filtering and processing EMM and ECM messages with commands for setting rights and session keys for access to events included in virtual channels, as well as decryption of control words for decryption of content events included in virtual channels; - processing of virtual channel metadata, including at least the name of the channels and their position number in the list of broadcast channels, as well as the schedule of events of the service's virtual channels, generated on the transmitting part of the service in the form of a selection of events of the content of the linear broadcast channels, broadcast within the framework of the service's virtual channels sequentially in time and simultaneously with the corresponding broadcast of the linear channel event, with the installation for each event of the selection of the identifier of the corresponding virtual channel and a mark of the use of the event in its composition; - adding virtual channels in the STB user interface based on their parameters in the list of linear channels; - formation of a schedule of virtual channels and its display 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 the virtual channel by automatically switching to a linear broadcast channel that broadcasts the content 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 in the event of their successful decoding. 12. The method according to item 11, characterized in that when forming an MPEG-2 transport stream by means of a multiplexer, additional service information is embedded into the transport stream, subsequently transmitted to the input of the client device, which is a Linkage descriptor in the network information table (NIT), ensuring dynamic detection by the client device of the metadata of the virtual channel service in the transport stream, and on the client device, detection of the service with the metadata in the transport stream is carried out by means of the said Linkage descriptor without a user feedback channel. 13. The method according to any of paragraphs 11, 12, characterized in that when generating a schedule of virtual channels of the EPG service by the server, when events of the selection broadcast by different linear broadcast channels intersect in time for a virtual channel, an event with an earlier broadcast time is added to the schedule, and for the time when events of linear broadcast channels are not displayed, a technological event preset in the service system is added to the schedule of the virtual channel. 14. The method according to item 11, characterized in that the decryption of the corresponding content after automatic switching to a linear broadcast channel that broadcasts a content event as part of a virtual service channel, the configuration of elementary streams of the transport stream for the descrambler in accordance with the information of the PMT service table for receiving ECM messages and the installation of control words in the descrambler are carried out by means of a main processor designed to ensure the possibility of decrypting the incoming encrypted stream by means of a built-in security system. 15. The method according to item 11, characterized in that the decryption of the encoded content is carried out by means of a cryptomodule and a smart card or a smart card emulator built into the cryptomodule, which ensure the storage of OpKey session keys and access rights to virtual service channels and content events, recorded by means of the cryptomodule after receiving the EMM message from the transport stream. 16. The method according to paragraph 11, characterized in that the descrambling of linear and virtual channels in accordance with subscriptions and with the provision of the possibility of descrambling the incoming encrypted transport stream and its transmission to the input of the main processor CPU is carried out by means of a conditional access system library installed in a software and hardware manner in the cryptomodule, implementing: - filtering and processing EMM messages with commands for setting rights and session keys for access to events included in virtual channels; - receiving and processing requests for descrambling virtual channel events generated by the main processor using a pre-installed software algorithm; - filtering and processing ECM messages to receive and decrypt the descrambling keys for events of linear channels included in the virtual channels and in the presence of the necessary access rights and session keys corresponding to the subscription; - initialization of descrambling of a given virtual channel using CW descrambling keys in case of their successful decryption; - transmission to the user interface of the receiving part of the service of information about subscriptions to the services of the virtual channel service and the current status of access to them. 17. The method according to item 16, characterized in that in the mode of automatic switching to the event of the content of the linear channel as part of the virtual channel of the service, by means of the main processor CPU, a request is generated and sent in a software and hardware manner to the cryptomodule for descrambling the corresponding content, and by means of the cryptomodule, an appeal to the smart card or the smart card emulator built into the cryptomodule is initiated to decrypt the control word for descrambling the content of the virtual channel and the elementary streams are configured for the descrambler in accordance with the information of the PMT service table for receiving ECM messages, and the control words CW received from the smart card are installed in the descrambler, ensuring the possibility of decrypting the incoming encrypted stream by means of the built-in security system. 18. The method according to paragraph 17, characterized in that by means of a software and hardware algorithm built into the smart card or built into the cryptomodule of the smart card emulator, the following is carried out: - decryption and storage of subscriber rights to access the package of linear and virtual service channels; - decryption and storage of session keys if there are valid rights to the channel package; - decoding and output to the CW library for descrambling of a given channel if there are valid viewing rights.