CZ330799A3 - Apparatus for repeated generation of message set - Google Patents

Abstract

The invention mostly includes a conventional digital television system (2000) for transmitting compressed digital signals. The multiplexer (2004) accepts a variety of additional entries signals, assembles one or more transport streams and transmits compressed digital signals to transmitter (2008) transmitter center via link (2010). Transmitter (2008) broadcasts electromagnetic signals through uplink (2012) where they are electronically processed and broadcast over theoretical downlink (2016) to terrestrial receiver (2018). The signals received by the receiver (2018) are transmitted to an integrated receiver / decoder (2020) connected end user device (2022). ReceiverDecoder (2020) decodes compressed MPEG-2 a signal to a signal for a television device (2022). System (3000) of the conditional access is connected to the multiplexer (2004) aprijimačenVdekodérern (2O20) is partly located in the transmitting center and partly in the receiver / decoder (2020). This system allows end users to access from one or more digital broadcasts broadcasters. Smart card, capable of decoding messages concerning one or more television programs by the broadcaster, the end user may be buy commercial offers either in the subscription mode or in pay-per-view mode.

Description

. Technical field

The present invention relates to a transmitting system, a conditional access system for a transmitting system, a transmitting and receiving system, a signal generating device (including messages), corresponding methods and signals for use with said systems, devices and methods.

BACKGROUND OF THE INVENTION

In particular, but not exclusively, the present invention relates to a mass market broadcast system having some or all of the following advantageous features. It is an information broadcast system, preferably a radio and / or television broadcast system.

• It is a satellite system (although it could be used for cable or terrestrial transmission).

It is a digital system, preferably using MPEG, particularly preferably MPEG-2, a compression system for

2O data / signal transmission.

• Provides interactivity.

Again, in particular, but not exclusively, the present invention relates to a subscriber authorization system (SAS, or else a subscriber authorization system) forming part of a conditional access system for a broadcast system. Preferably, SAS means any device, apparatus or system for authorizing users to have access to a conditional access system, regardless of the intended use. The SAS system could be used with radio and / or television broadcasting

3 ₀ system, but equally could be used to authorize users, for example, in computer networks, parking places and so on. Preferably, the SAS also has the function of generating appropriate authorization messages.

The function of known subscriber authorization systems is to manage access rights to television programs available as commercial offers and sold according to various modes of commercialization (constant charge mode, pay or order mode, pulse mode). According to these rights and according to the information received from the subscriber control system (SMS, or also the subscriber management system), SAS creates so-called Authorization Control Messages (EMMs), which are transmitted by the message transmitter via the multiplexer to the subscriber receiver / decoder for authorization. .

In the known system, the message transmitter does not have the ability to sense or control what it transmits to the multiplexer. Thus, it has been found feasible according to the present invention that it is possible for the message transmitter to be able to transmit two EMMs to be received and decoded by the receiver / decoder in short. In such circumstances, it is possible that if the EMMs are insufficiently separated, the receiver / decoder will be unable to sense and decode correctly the other of the EMMs. This can cause serious authorization problems.

In its first aspect, the present invention aims to solve this and other problems.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provided a message set recreating device comprising:

means for generating a plurality of messages;

means for repeatedly randomizing the order of the messages to form a plurality of sets of such messages, such that the messages of each set are in random order; and means for transmitting a plurality of message sets.

By repeatedly randomizing the sequence of messages, the chance that two messages will be transmitted only abbreviated after a certain number of repetitions can be reduced to a negligible extent.

Preferably, the reporting means comprises means for storing the generated messages and, if so, the random distribution means is preferably arranged to produce each of said set of messages by selecting the messages in random order from said storage means. This can be a particularly effective way of putting the present invention into practice, since the messages do not then have to be re-created each time the order of the messages is randomly distributed.

For easy access, the storage means is preferably arranged to store messages in at least a two-dimensional array. Additional dimensions may be added, for example, to represent the different operators for which messages can be created.

Preferably, the apparatus further comprises means associated with the output means for varying the rates at which a plurality of message sets are transmitted. In this way, any bit rate entered from the multiplexer can be considered.

For the same reason, the device preferably further comprises means associated with the memory means for evaluating the size of the messages stored in the memory means and means associated with the output means for changing the rate at which a plurality of message sets are transmitted depending on said message size.

Preferably, the message generating means and the random distribution means are connected via a FIFO device (first in, first out). Because these two components can be a long distance away, providing a FIFO device can enable them to operate independently in the event of one of them failing. For the same reason, the output means preferably comprises means for storing at least one of the message sets so that it can again operate effectively in a stand-alone mode.

A plurality of output means may be provided, in which case the apparatus preferably further comprising a multiplexer for receiving a plurality of message sets transmitted by said plurality of output means.

The present invention also relates to an access control system for a transmitting and receiving system, the access control system including at the transmitting end of the device as described above and at the receiving end of the device for receiving said messages.

The message may be an authorization message for transmission to the receiving device. Furthermore, the entitlement message may be an EMM or an ECM. In a preferred embodiment, the output means comprises an EMM inserter for introducing the EMM into the data stream to be transmitted.

The present invention further relates to a transmission and reception system comprising an access control system as described above; the system may be designed for digital broadcasting of television programs.

The present invention also relates to a method of recreating a set of messages, comprising:

generating a number of messages;

repeatedly randomizing the order of the messages to form a plurality of sets of these messages so that the messages in each set are in random order; and forwarding a plurality of message sets.

Preferably, the method comprises the step of storing the messages generated in the message generation step, and in the random distribution step, preferably each said set of messages is created by selecting the messages in random order.

The present invention also relates to a method of controlling user access to a transmitting and receiving system, comprising at the transmitting end a method of re-creating a set of messages 15 as described above, and at the receiving end a step of receiving said messages. Preferably, the message is an authorization message for receipt through the receive step.

Another aspect of the present invention will now be discussed. Typically, when transmitting a digital bitstream, the information is transmitted as a digital data packet and an identifier for that packet; wherein the identifier has a length of at least two bytes.

According to the present invention, the output means 25 mentioned above is preferably arranged to transmit a plurality of sets as a digital signal comprising a packet (particularly preferably a plurality of packets) of digital data and an identifier for the packet, the identifier having a length of less than two bytes. less). This can result in reduced bandwidth requirements.

This feature is provided independently. Thus, according to a second aspect of the present invention, there is provided a digital signal generating apparatus comprising a digital data packet and an identifier for that packet, comprising:

means for creating a data packet; and means for generating an identifier; whereas:

the means for generating an identifier is arranged to produce an identifier having a length of less than two bytes.

The identifier may include an identity parameter and a length parameter, in which case preferably these parameters are each 4 bits long for ease of implementation.

Preferably, the digital value of the length parameter 15 is not proportional to the actual length of the packet. This may allow a greater range of the actual packet length than the digital value of the length parameter. In addition, the device may include means for storing a lookup table that provides connections or relationships between the digital value of the length parameter and the actual length of the packet.

This aspect of the present invention also relates to a transmitting and receiving system comprising, at the transmitting end of a device as described above, and at the receiving end of a device for receiving said signal.

In addition, in the method of the above description, a plurality of messages may be transmitted as a digital signal comprising a digital data packet and an identifier for the packet, the identifier having a length of less than two bytes.

In its independent method implementation, the second aspect of the present invention relates to a method for generating a digital signal comprising a digital data packet and an identifier for the packet, the method comprising:

creating a data packet; and creating an identifier; the identifier has a length of less than two bytes.

Preferably, the identifier includes an identity parameter and a length parameter. Also preferably, the digital value of the length parameter is not directly proportional to the actual length of the packet.

A second aspect of the present invention also relates to a digital signal comprising:

digital data packet; and an identifier for the packet; and wherein:

the identifier is less than two bytes in length.

Preferably, the identifier includes an identity parameter and a length parameter 20, wherein the identity and length parameters each have 4 bits in length and the digital value of the length parameter is not directly proportional to the actual length of the packet.

The third aspect of the present invention will be discussed in the following description. Conventional broadcast systems are usually subject to severe bandwidth constraints.

Therefore, preferably, if the transmitting and receiving system of the above description additionally comprises means for transmitting data, it also includes means for generating a control command representing data characteristics, and the output means comprises means for retransmitting a plurality of variable rate message sets and changing the repeat rate. speed in response to a control command.

This feature is independently provided according to the third aspect of the present invention. According to this third aspect of the present invention, there is provided a broadcast system comprising:

means for transmitting data; means for generating a control command representing data characteristics; and Ιθ means for retransmitting a variable rate message; said transmitting means for transmitting the message being arranged to change the repetition rate in response to the control command.

By changing the repetition rate in response to the control command, the bandwidth can be allocated dynamically for specific messages.

In a preferred embodiment of the invention, the data is signals representing events in a program (preferably events in a digital television or radio program) and the control command generating means is arranged to produce a command that represents the transmission time of a particular event in the program. This aspect is particularly relevant to pay-per-view (PPV) events, where viewers' entitlements to authorization to watch a particular PPV event will generally vary according to the proximity of the broadcast of that event.

The control command can be created by a program transmitter, possibly via a so-called Program Channel Service Channel (SPB).

Preferably, said transmission means for transmitting messages is arranged to change the repetition rate in the vicinity of the event transmission time. Advantageously, said message transmitting means is also arranged to increase the repetition rate before the event transmission time and also to increase the repetition rate during the event transmission time.

For example, for a particular PPV program event, the increased rate may begin perhaps 30, 20, 15, 10, or 5 minutes before the event broadcast time, and may continue up to about 10, half, three quarters, or even throughout the event. The lower rate may be one transmission every 30 or 15 minutes, while the increased rate may be one transmission every 2 or one minute or every 30 seconds. Of course, the actual speed may not be exactly at the above intervals; however, intermediate intervals are also possible, wherein the lower speed may be slower than once every 30 minutes and the increased speed may be faster than once every 30 seconds.

A third aspect of the present invention also relates to a transmitting and receiving system comprising, at the transmitting end, a system as described above and at the receiving end of a device for receiving transmitted data and messages.

This aspect also relates to a broadcasting method comprising:

data transmission;

generating a control command representing data characteristics; and retransmitting a message with a variable repeater 30 at a rate that changes in response to the control command.

Preferably, the data is signals representing program events, and the control message represents the transmission time of a particular program event.

Preferably also, the repetition rate is varied near the event transmission time. Particularly preferably, the repetition rate is increased before and also, preferably, during the event transmission time.

In conventional conditional access systems, problems may arise as a result of a failure of the connection between SMS and SAS due to the fact that these resources may be remote by a certain physical distance.

According to a fourth aspect of the present invention, there is provided a conditional access system for providing conditional access to subscribers, the system comprising:

Subscriber Control System (SMS); and a subscriber authorization system (SAS) associated with the subscriber control system, said authorization system including means for generating subscriber refresh commands and means for authorizing subscriber recovery depending on the commands.

By inserting the means for generating subscription renewal orders into the SAS, rather than the SMS as previously, the exchange of commands between the SAS and the SMS can be minimized. Thus, the ability to cooperate with SAS and SMS can also be reduced.

A fourth aspect of the present invention also relates to a conditional access system for providing conditional access to subscribers, the system comprising:

a subscriber control system for managing subscribers, including a subscriber information database and means for generating (preferably from this database) a stop command that a particular connection is to be stopped; and a subscriber authorization system for authorizing subscribers coupled to the subscriber control system and configured to receive a stop command; wherein the subscriber authorization system comprises means for generating a subscriber renewal command for each subscriber depending on the stop command for that subscriber, and means for authorizing the subscriber renewal depending on the subscriber renewal orders.

Preferably, the subscriber control system comprises means for generating (again preferably from said database) a start command 5 that a connection is to be initiated, and the means for generating subscriber renewal commands of the subscriber authorization system is arranged to generate each subscriber renewal command in further dependency thereon. start command. Therefore, SAS can handle not only renewing existing subscribers, but also initial connection and authorization of new subscribers.

The subscriber authorization system may also include a subscriber information database, preferably in this case also including means for updating the information in that database as a function of the information in the subscriber control system database. This can protect against the failure of the connection between SMS and SAS.

For the same reason, a first in first first out (FIFO) device is placed between the means for generating subscriber refresh commands and the means for authorizing refresh to equalize the flow of the command and to ensure that no command is lost in the event of failure.

The authorization renewal means may include output means for passing authorization entitlement messages to the authorization renewal participants. In a preferred embodiment, the messages are EMMs.

The subscriber authorization system may be able to provide special rights (such as free access for a limited period of time) to new subscribers. This can give the system some versatility and adaptability.

The present invention also relates to a conditional access system for a transmitting and receiving system, the system comprising at the transmitting end a system as described above, and further comprising at the receiving end a device for receiving said messages.

The present invention further relates to a transmission and reception system comprising a conditional access system as described above. This system is usually designed to broadcast digital TV and radio programs.

Preferred features of the present invention will be described in the following description purely by way of example embodiments with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows the overall architecture of a digital television system according to a preferred embodiment of the present invention;

Figure 2 shows the architecture of a conditional access system in a digital television system;

Giant. 3 illustrates the structure of an authorization control message (EMM) used in the conditional access system;

Giant. 4 is a schematic hardware diagram of a subscriber authorization system (SAS) according to a preferred embodiment of the present invention;

Giant. 5 is a schematic diagram of an SAS architecture;

Giant. 6 is a schematic diagram of a subscriber control system serving channel forming part of a SAS;

Giant. 7 illustrates a flow chart of a procedure for automatically reconnecting subscriber connections as implemented by SAS;

Giant. 8 is a schematic diagram of a subscriber connection group bitmap used in the automatic refresh procedure;

Giant. 9 illustrates an EMM structure that is used in an automatic refresh procedure;

Fig. 10 shows in detail the structure of the EMM;

Fig. 11 shows a schematic diagram of a command centralized serving channel when used to receive commands directly over communication serving channels;

Fig. 12 schematically illustrates a portion of Fig. 2 showing one embodiment of the present invention;

Fig. 13 shows a schematic diagram of a command centralized service channel when used to receive commands from a subscriber authorization system for a request for a query;

14 is a schematic diagram of communication service channels; FIG.

Fig. 15 illustrates how the transmission cycle rate of EMMs is varied according to the timing of the PPV event;

Fig. 16 is a schematic diagram of a message transmitter used to transmit EMMs;

FIG.17 is a schematic diagram illustrating a method of storing EMMs in a message transmitter;

Fig. 18 shows a schematic diagram of a smart card;

Fig. 19 shows a schematic diagram of the arrangement of the zones in the memory of the smart card; and

20 is a schematic diagram of a description of a PPV event.

DETAILED DESCRIPTION OF THE INVENTION

An overview of the digital television broadcasting and receiving system 1000 according to the present invention is shown in Fig. 1. The invention includes a mostly conventional digital television system 2000 that uses the known MPEG-2 compression system to transmit compressed digital signals. More specifically, the MPEG-2 compressor 2002 at the broadcast center receives a digital signal stream (usually a video signal stream).

The compressor 2002 is coupled to the multiplexer and encoder 2004 via a link 2006. The multiplexer 2004 receives a plurality of additional input signals, assembles one or more transmit streams, and sends compressed digital signals to the transmitter center 2003 of the broadcast center over the 2010 link. including telecommunication lines. Transmitter 2008. transmits electromagnetic signals via uplink 2012 to satellite transponder 2014, where these signals are electronically processed and transmitted via theoretical downlink 2016 to terrestrial receiver 2018, typically in the form of a parabolic antenna owned or rented by the end user. The signals received by receiver 2018 are transmitted to an integrated receiver / decoder 2020 owned or rented by the end user and associated with the end user television equipment 2022. The receiver / decoder 2020 decodes the compressed MPEG-2 signal into a television signal for the television device 2022.

The conditional access system 3000 is coupled to the multiplexer 2004 and the receiver / decoder 2020 and is located partly in the broadcast center and partly in the decoder. This system allows the end user to access digital television broadcasts from one or more broadcasters. A smart card capable of decoding commercial offerings messages (i.e., one or more television programs sold by the broadcaster) can be inserted into the receiver / decoder 2020. Using the decoder 2020 and the smart card, the end user can purchase broadcast events either in subscription or pay-per-view mode.

Also connected to the multiplexer 2004 and the receiver / decoder 2020 is an interactive system 4000, which is again located partially in the broadcast center and partly in the decoder, and which allows the end user to interact with various applications via modem return channel 4002.

The conditional access system 3000 will be described in more detail below.

It can be seen from Figure 2 that the conditional access system 3000-5 includes a subscriber authorization system (SAS) 3002. The SAS 3002 is connected to one or more subscriber control systems (SMS) 3004, with one SMS 3004 being for each broadcast provider , via an appropriate TCP-IP connection 3006 (although other connection types could alternatively also be used). Alternatively, the SMS 3004 barley could be shared between two broadcast providers, or one broadcast provider could use two SMS 3004 and the like.

First coding units in the form of encryption units

3008, using the parent smart cards 3010, are associated with the SAS 3002 connection 3012. The second coding units again in the form of encryption units 3014 using the parent smart cards 3016, are associated with the multiplexer 2004 by the connection 3018. The receiver / decoder 2020 receives the daughter smartcard 3020 Receiver / Decoder

2020 is connected directly to SAS 3002 via communication service channels 3022 via modem return channel 4002. SAS 3002 transmits, among other information, login rights to daughter smart card 3020 as required.

Smart cards contain secret information from one or more commercial operators, the parent smart card encodes different types of messages, and daughter smart cards decode those messages if they are authorized to do so.

The first and second encryption units 3008 and 3014 include a frame, an electronic VME card with software stored on an EEPROM, up to 20 electronic cards, and one smart card 3010 and 3016 respectively for each electronic card, one (card).

3016) for encoding ECMs and one (card 3010) for 15 EMM encoding.

The operation of this conditional access system 3000 of the digital television system will now be described in more detail below with reference to various components

2o digital television system 2000 and conditional access system 3000.

Multiplexer and encoder

As shown in Figures 1 and 2, in the 25 broadcast center, the digital video signal is first compressed (or reduced in bit rate) using the MPEG-2 compressor 2002. This compressed signal is then transmitted to the multiplexer and encoder 2004 over the 2006 connection to be multiplexed with other data, such as additional compressed data.

The encoder generates a control word used in the encoding process and included in the MPEG-2 stream in the multiplexer 2004. The control word is internally generated and allows the integrated receiver / decoder 2020 of the end user to decode the program.

Access criteria that indicate how the program is commercialized are also added to the MPEG-2 stream. The Program may be commercialized by any one of a number of subscription modes and / or one of a number of pay-per-view modes (PPVs) or events. In the subscription mode, the end user subscribes (participates) to one or more commercial offers or files, giving him the right to watch each channel within those files.

In a preferred embodiment, up to 960 commercial offers can be selected from the channel set. In pay-per-view mode, the end-user is equipped with the option to purchase events as desired. This can be achieved either by pre-ordering the event in advance (order mode) or by purchasing the event once it is broadcast (pulse mode). In a preferred embodiment, all users are subscribers, whether or not they are watching in subscription or PPV mode, but of course, PPV viewers may not be necessary subscribers.

Both the control word and the access criteria are used to build an Authorization Control Message (ECM); which is a message transmitted in connection with one coded program; wherein the message includes a control word (which allows program decoding) and access criteria of the transmitted program. The access criteria and the control word are transmitted to the second encryption unit 3014 via the 3018 connection. In this unit, the ECM is generated, encoded, and transmitted to the multiplexer and encoder 2004.

Each service transmitted by the broadcaster includes a number of separate components in the data stream;

for example, a television program includes a video component, an audio component, a subtitle component, and so on. Each of these service components is individually coded and encrypted for subsequent transmission to the response 2014. A separate ECM message ¹⁰ is required in conjunction with each coded service component.

Broadcasting of programs

The multiplexer 2004 receives electrical signals 25 including coded EMMs from the SAS 3002, coded message

ECM from the second encryption unit 3014 and compressed programs from the compressor 2002. The multiplexer 2004 encodes the programs and transmits the encoded programs, the encoded EMMs, and the encoded ECMs as electrical signals to the transmitter center 2008 of the broadcast center.

Transmitter 2008 sends electromagnetic signals towards satellite transponder 2014 via uplink 2012.

Receiving programs. ,

The satellite transponder 2014 receives and processes the electromagnetic signals transmitted by the transmitter 2008 and sends these signals to the terrestrial receiver 2018, usually in the form of a parabolic antenna owned or leased by the end user, via the downlink 2016. The signals received by the terrestrial receiver 2018 are transmitted to the 2020 owned or rented by the end user and associated with the end user television equipment 2022. The receiver / decoder 2020 demultiplexes the signals to obtain coded programs with encrypted EMMs and with encrypted ECMs.

If the program is not encoded, that is, no ECM in the MPEG-2 stream has been transmitted, the receiver / decoder 2020 decompresses the data and converts the signal into a video signal for transmission to the television device 2022.

If the program is coded, the receiver / decoder 2020 extracts the corresponding ECM from the MPEG-2 stream and forwards the ECM to the end user's smart card 3020. This is inserted into the slot in the receiver / decoder box 2020. The daughter card 3020 controls whether the end user has the right to decode the ECM and access the program. If not, a negative state is passed to the receiver / decoder 2020 to indicate that the program cannot be decoded. If the end user has the appropriate rights, it is

2Q, the ECM is decoded and the control word is extracted. The decoder 2020 can then decode the program using this control word. The MPEG-2 stream is decompressed and converted to a video signal for subsequent transmission to the television device 2022.

Subscriber Control System (SMS)

Subscriber Control System (SMS) 3004 includes a database 3024 that manages, inter alia, all end-user sets, commercial offers (such as tariffs and advertisements), subscriptions, PPV details, and end-user consumption and authorization data. SMS 3004 may be physically remote from SAS 3002.

Each SMS 3004 transmits messages to the SAS 3002 via a corresponding link 3006 that includes modifications or 5 generation of Authorization Control Messages (EMMs) to be transmitted to end users.

SMS 30Q4 also sends messages to SAS 3002. which do not include any modification or generation of EMMs, but only include an end-user status change (regarding authorization granted to the end user when ordering products or a value to be charged to the end user).

As described in the description below, the SAS 3002 sends messages (typically requiring information such as consultation information or billing information) to the SMS 3004, so it is clear that the communication between the two components is two-way.

Authorization Control Messages (EMM)

An EMM is a message assigned only to an individual end-user (subscriber) or group of end-users (as opposed to an ECM that is assigned to only one scrambled program or set of scrambled programs if 25 are part of the same commercial offering). Each group can contain a given number of end users. This grouping organization aims to optimize bandwidth utilization; that is, access to a single group can enable more end users to be reached.

Various specific types of EMMs are used in the practice of the present invention. Individual EMMs are assigned to individual subscribers and are typically used to provide pay-per-view services; these messages containing the group identifier and the location of the subscriber in the group. The so-called group EMM subscriber messages are assigned to groups, say, 256 individual subscribers, and are usually used to manage certain subscriber services. This EMM has a group identifier and a subscriber group bitmap. EMMs are assigned to entire audiences and can, for example, be used by an operator to provide certain free (free) services. An audience is the total of subscribers having smart cards that contain the same operator identifier (OPI). Finally, a specific EMM is addressed to a specific smart card identifier.

The structure of a typical EMM will be described below with reference to Fig. 3. The EMM, which is implemented as a series of digital data bits, basically includes a header 3060, an EMM itself 3062, and a signature 3064.

Header 3060 further includes a type identifier 3066 for identifying whether the message is individual, group, audience, or any other type message, identifier 3068 that indicates the length of the EMM, an additional address 3070 for the EMM, operator identifier 3072, and key identifier 3074. Of course, the EMM 3062 itself varies considerably according to its type. Finally, the signature 3064, which is typically 8 bytes long, provides a certain number of checks against damaging the remaining data in the EMM.

Subscriber Authorization System (SAS)

The messages generated by the SMS 3004 are forwarded via the connection 3006 to the subscriber authorization system (SAS) 3002, which further generates messages confirming the receipt of the messages generated by the SMS

3004 and passes these confirmations to SMS 3004.

As shown in FIG. 4, at the hardware level of the SAS, the computer 3050 (preferably a DEC computer) associated with one or more data and command keyboards 3052 in a known manner comprises one or more 10 ' VDU) 3054 for displaying output information and data storage means 3056. A certain backup (redundancy) in the hardware can be provided.

At the software level, the SAS operates, preferably 15 on a standard VMS operating system, according to a software scheme whose architecture will now be described in reference with reference to Fig. 5; it should be understood that software could alternatively be implemented in hardware.

2θ In the SAS overview, the 3100 Subscriber Chain area for providing subscription rights and renewal rights automatically includes monthly, the 3200 pay-per-view chain for granting rights for PPV events, and the 3300 EMM loader for relaying EMMs generated by the Subscriber Chain areas, and of the PPV chain, to the multiplexer and encoder 2004, and thus to fulfill the MPEG stream of the EMM. If other rights are to be granted, such as File Payments Rights (PPEs) when downloading computer software to a user's personal computer, other similar areas are also created.

One function of the SAS 3002 is to manage access rights to television programs available as commercial offerings in subscriber mode or sold as PPV events according to various modes of commercialization (e.g., order mode, pulse mode). creates EMM messages for the subscriber.

The subscriber chain area 3100 includes a command interface (C1) 3102, a subscriber technical management (STM) service channel 3104, a message generator (MG) 3106, and an encryption unit 3008.

The PPV chain area 3200 includes an authorization service channel (AS) 3202, a relational (relational) database 3204 for storing relevant details for end users, a local Black List database (list of 15 defaulters), database database service channels 3206, a command centralized service channel (OCS) 3207. Program Channel (SPB) Service Channel 3208, Message Generator (MG) 33210, the function of which is essentially the same as the Message Generator function for the Subscriber Chain Region and will therefore not be further described herein, and Encryption Unit 3008 .

EMM inserter 3300 includes a plurality of transmitters 3302,

3304, 3306 and 3308 messages (ME) and software multiplexers (SMUX)

3310 and 3312. In a preferred embodiment of the present invention, two ME 3300 and 3304 are used for the message generator 3106, and two more ME 3306 and 3308 for the message generator 3210. ME 3302 and 3306 are associated with SMUX 3312. while ME 3304 and 3308 are associated with SMUX 3312.

Each of the three main SAS components (the subscription chain region, the PPV chain region, and the EMM bootloader) will now be described in some detail.

Subscriber chain area

First, the subscriber chain area 3100 in which command interface 3102 is intended to assign messages from SMS 3004 to STM server 3104 and also to OCS 3206, and from OCS 3206 to SMS 3004, will be described. direct commands or batch files containing commands. This interface performs parsing of messages coming from STM server 3104 and is able to transmit correct messages when an error occurs in the message (out-of-range parameter, missing parameter, and so on). This interface further monitors incoming commands in text form in the tracking file 3110 and also in binary form in the playback (repeating) file 3112 to be able to play (repeat) a series of commands. Tracking may be disabled and file size may be limited.

In the following description, a detailed discussion of STM service channel 3104 will be made with reference in particular to FIG. . As shown in the figure, the commands are passed to the message generator 3106, although in a different format than the format in which these commands are passed to the STM server 3104. For each command, the STM server 3104 is arranged to send an acknowledgment message to Cl 3102 only when the relevant row2 has already been successfully processed and sent to MG 3106.

The STM server 3104 includes a subscriber database 3120 in which all relevant subscriber related parameters (smart card number, commercial offer, status, group and location in that group, and the like) are stored. This database 3120 performs semantic checks on the commands transmitted by the C1 3102 relative to the contents of the database 3120 and updates the database 3120 when the commands are valid.

STM server 3104 further manages first in-out (FIFO) buffer 3122 between STM server 3104 and MG 3106 as well as a backup FIFO disk 3124. The purpose of these FIFO elements is to average the flow of commands from C1 3102 if MG 3106 is not capable of responding for some time for any reason. These FIFO elements can also ensure that in the event of a STM server 3104 or MG 3106 collision, no command is lost because the STM server 3104 is arranged to empty (i.e., send to the MG 3106) its FIFO element when restarted. FIFO elements are implemented as files.

The STM server 3104 in its memory core includes an auto-refresh server 3126 that automatically creates a refresh and, if required by the operators, free rights. In this context, the creation of renewals can be considered to include the creation of rights for the first time, although it is clear that the creation of new rights is initialized in SMS 3004. As will be seen, these two things can be treated with roughly the same commands and EMMs.

The fact that the STM server 3104 is separate from SAS 3002 and the automatic renewal server inside SAS 3002 rather than (in known systems) in SMS 3004 is a particularly important feature, as this can significantly reduce the number of commands that must be transmitted from the SMS 3004 to SAS 3002 (taking into account that SMS and SAS may be in different locations and operated by different operators). In fact, the two main commands required from SMS 3004 are only commands that a new subscription should be started and that the existing subscription should be stopped (for example in case of non-payment). By minimizing the exchange of commands between SMS 3004 and SAS 3002, the possibility of failing transmission of commands in connection 3006 between the two elements is also reduced; and also the design of the SMS 3004 need not generally take into account the features of the conditional access system 3000.

The automatic refresh is implemented as outlined in the flowchart of Figure 7. In order to reduce bandwidth and since a large percentage of all refreshes are standard, the refresh is implemented in subscriber groups; in preferred embodiments of the invention there are 256 individual participants per group. The flowchart begins with the start step 3130 and proceeds to step 3132, in which the monthly activation of the refresh function is performed (although it should of course be understood that other refresh rates are also possible). With a monthly renewal frequency, rights are granted to the end user for the current month and the entire following month, at the end of which they will cease to be valid unless renewed.

In step 3134, subscriber database 3120 is accessed with respect to each group and each individual within that group to determine whether rights for a particular individual should be restored.

At step 3136, as shown in FIG. 8, a group subscription bitmap $ is constructed according to the contents of the subscriber database 3120. This bitmap includes group identifier 3138 (in this case group 1-G1) and 256 individual subscriber zones 3140. The individual bits in this bitmap are set to 1 or zero depending on whether or not a particular subscriber is to have his rights restored. A typical binary data set is shown in the figure.

At step 3142, appropriate commands, including a group subscription bitmap, are passed to message generator 3106. In step 3143, the message generator 3106 sets the obsolescence date to indicate to the smart card dates beyond which a particular subscriber EMM is no longer valid; usually this date is set as the end of the following month.

In step 3144, the message generator 3106 generates appropriate EMMs for the subscriber group from commands and requests the encryption unit 3008 to encrypt these EMMs, and the encrypted EMMs are then forwarded to the EMM loader 3300, which in step 3146 introduces these EMMs into the data stream. MPEG-2.

Step 3148 indicates that the above procedure is repeated for each group. Finally, the process is terminated at exit step 3150.

In fact, the flow chart described above with reference to FIG. 7 relates specifically to the renewal of a subscription. STM channel 3104 also manages free audience rights and new subscribers in a similar manner.

In the case of free audience rights available for specific programs or groups of such programs, these rights are created through the STM server 3104, which then commands the message generator 3106 to create appropriate EMM audience reports (for the entire audience) with a date of obsolescence after that number of days (or weeks). The MG 3106 calculates the exact date of obsolescence based on the command from STM server 3104.

As regards new entrants, they are processed in two stages. First, when purchasing a smart card to the receiver / decoder 2020 (if requested by the operator), the subscriber acquires free rights for a given period of time (usually several days). This is achieved by creating a bitmap for the subscriber that contains the relevant obsolescence date. The subscriber then hands over the application to the operator managing the subscriber (in SMS). Once this application has been processed, the SMS will deliver to SAS a start order for that particular subscriber. Upon receiving this start order at SAS, the STM instructs MG to assign a unique address to this new subscriber (with a certain group number and location in that group) and to create a special so-called EMM commercial subscription subscription message (compared to the more common EMM subscription group message) , which is being used for renewal) to secure that particular rights participant until the end of the following month.

From this point on, the renewal of the new subscriber can proceed automatically as described above. Through this two-stage process it is possible to grant new subscribers rights until the SMS issues a stop command.

It should be noted that the commercial offer subscription EMM is used for new subscribers and for reactivation of existing subscribers. The group subscription EMM is used for renewal and stopping purposes.

As can be seen from FIG. 9, a typical custom EMM (i.e., ignoring header and signature) subscription that is generated by the above-described procedure includes the following main part, in particular typically 256 bits of the subscription bitmap 3152 (or subscriber group). 128 bits of control encryption keys 3154 for encrypting the message

EMM, 64 bits of each used encryption key 3156 to enable smart card 3020 to decrypt the control word to provide access to broadcast programs, and 16 bits of obsolescence data 3158 to indicate the data beyond which the smart card 5 will ignore this EMM. In fact, in a preferred embodiment of the invention, three used keys are provided, one set for the current month, one set for the following month, and one set for recovery purposes in the event of a system failure.

More specifically, the custom group subscription EMM message has all of the above components except for the control encryption keys 3154. The custom commercial subscription subscription message (which is for a single subscriber) includes, instead of the complete subscriber group bitmap 3152, the group identifier followed by the location in that group. and then the control encryption keys 3154 and the three used keys 3156 followed by the relevant obsolescence date 3158.

The message generator 3106 is used to convert the commands issued by the STM by the service channel 3104 to EMMs for transmission to the message transmitter 3302. As seen in FIG. 5, MG

3106 first creates its own EMMs and forwards them to the encryption unit 3008 for encryption relative to the control and used keys. CU 3008 completes EMM signature 3064 (see Fig.

3) and passes the EMM back to MG 3106, where the 3060 header is added.

Therefore, the EMMs that are transmitted to the message transmitter 3302 are full EMMs. The message generator 3106 also determines the start and stop times and the transmission speed of the EMMs, and passes this information as appropriate commands together with the EMMs to the message transmitter 3302. MG 3106 generates a given EMM only once; the element that carries out its cyclic transmission is ME 3302.

Referring again to FIG. 5, the report generator 3106 includes its own EMM database 3160 that stores the EMM for the duration of the relevant EMM. This 15 EMM message is deleted as soon as its transmission time has expired. This database 3160 is used to ensure consistency between the MG 3106 and the ME 3302, so that, for example, when the end user is excluded (stopped), the ME 3302 will not continue to transmit refresh. In this context, the MG 3106 calculates the relevant operations and sends them to ME 3302.

When creating an EMM, the MG 3106 assigns a unique identifier to the EMM. When the MG 3106 forwards the EMM to the ME 3302, it also forwards this unique identifier (ID) for the EMM. This allows the identification of a specific EMM in both MG 3106 and ME 3302.

Also, with respect to subscriber chain region 3100, message generator 3106 includes two FIDO memories 3162 and 3164, one for each of the relevant message transmitters 3302 and 3304 in the EMM loader 330, for storing encrypted EMMs.

Because region 3100 of the subscriber chain and loader 330

The EMMs can be spaced a considerable distance, allowing the use of these FIFO memories allows complete continuity in EMM transmission, even if links 3166 and 3168 fail between the two elements.

Similar FIFO memories are used in the 3200 pay-per-view chain.

One particular feature of the message generator 3106 in particular and the conditional access system 3000 generally relates to the manner in which it limits the length of the EMM 3062 itself by mixing the length parameter and the space saving identifier θ. This will be described in the following description with reference to Fig. 10, which illustrates an exemplary EMM (in fact the PPV EMM, which is the simplest EMM). The length reduction occurs in Pid (packet or parameter identifier) 3170. It includes two parts, the ID 3172 and the length parameter 3174 for the packet (needed to identify the beginning of the next packet). The entire Pid 3170 is expressed in just one byte of information, where 4 bits are reserved for the ID and four bits are reserved for the length parameter. Because 4 bits are not sufficient for

Defining a length in a truly binary manner, using a different relationship between the bits and the actual length, which relationship is represented in the lookup table stored in the memory area 3178 in the message generator 3106 (see FIG. 5). The relationship is usually as follows

0000-0

0001 - 1

0010 = 2

0011 = 3

0100 = 4

0101 = 5 0110 = 6 0111 = 7 1000 = 8 1001 = 9 1010 - 10 1011 = 11 1100 = 12 1101 = 16 1110 = 24 1111 - 32

It should be noted that the length parameter is not directly proportional to the actual length of the packet; the relationship is partially more quadratic rather than linear. This allows a greater range of packet length.

Pay Per View Chain Area

Referring to the pay-per-view chain area 3200, as shown in more detail in FIG. 5, the authorization server 3202 has a command centralized server 3207 on its client requesting information about each subscriber connecting to the communication server 3022 for the client. to purchase a PPV product.

If the subscriber is known from AS 3202, a set of transactions takes place. If the subscriber is authorized for the order, AS 3202 creates an invoice (account) and sends it to OCS 3207. Otherwise, AS 3202 signals to OCS 3207 that the order is not authorized.

Only at the end of this set of transactions, AS 3202 updates the end-user relational database 3204 via database service channels (DBAS) 3206 if at least one transaction has been authorized; which optimizes the number of database accesses.

The criteria by which AS 3202 authorizes purchases are stored in a database accessed via DBAS processes. In one embodiment of the invention, the database is the same as the database that the STM enters.

Depending on the consumer profile, authorization may be denied (PPV_disabled, Casino_disabled ..). These types of criteria are updated by STM 3104 on behalf of SMS 3004.

Other parameters, such as limits allowed for purchases (either credit card, automatic payment, or the number of authorized purchases made per day) are also checked.

In case of credit card payment, the card number is checked against the local black list (list of debtors or uncovered cards) stored in the local black list database 3205.

If all verifications are successful, then AS: 1. Creates an invoice (account) and sends it to OCS, which completes this invoice and saves it in a file, which is later sent to SMS for processing (current customer billing; and

2. Updates the database, mainly to set new purchase limits.

This check-and-create-invoice mechanism $ if-OK is applied to every command that a subscriber can request during one session (it is possible to order, for example, 5 movies (shows) per session).

It should be noted that the AS has limited information concerning the participant compared to what it has at its disposal

SMS. For example, the AS does not have a subscriber's name or address. On the other hand, AS has a subscriber's smart card number, a consumer's consumer category (so different orders can be made for different subscribers), and different flags that indicate, for example, whether the subscriber can buy on credit or is excluded or stolen card. Using a limited amount of information can help limit the time required to authorize a particular subscriber request.

The main purpose of DBAS 3206 is to enhance database performance in terms of AS 3202 through parallel approaches (so there is little point in defining an arrangement with only one DSAS 320 6). The AS 3202 parameter specifies how much DBAS 3206 should join. A given DBAS 3026 can be associated with only one AS

3202.

OCS 3207 mainly works with PPV commands and works in several modes.

First, OCS 3207 works to process commands issued by SMS 3004, such as product recovery (for example, if an invoice is already stored by SMS 3004, the invoice is not created by OCS 32071, the wallet is updated in smart card 3020. and the connection is canceled / updated.

The different steps in this procedure are: 1. Identification of relevant subscriber (using AS 3202);

2. In the case of validity, create corresponding commands to the message generator to send the appropriate EMM message. The commands can be:

product orders, wallet updates, clearing connections.

Note that these operations do not involve creating billing information, as billing is already known from SMS. These operations are adapted to purchase free products.

Secondly, the OCS 3207 handles commands received from subscribers via communication service channels 3022. These commands can be received either via a modem connected to the receiver / decoder 2020, or via voice activation via telephone 4001, or via key activation via MINITEL, PRESTEL or similar system if available.

Third, OCS 3207 handles callbacks issued from SMS. These last two modes of operation will now be discussed in more detail below.

In the second type of mode described above, the OCS 3207 operates with commands received directly from the end user (subscriber) via communication service channels 3022.

These commands include product orders (for example, for a specific PPV event), subscriber modifications required by a participant, and resetting the parent code (the parent code is a code through which parents can restrict access to certain programs or program classes).

The manner in which these commands are processed will now be described in more detail with reference to FIG. 11.

Product orders placed by a participant include the following steps: 1. Via AS 32Q2, a caller ID that makes a call through CS 3022 and orders a specific product;

2. Verifying the validity of the caller's request, again using AS 3202 (where the order is placed using the receiver / decoder 2020, this is achieved by verifying the details of the smart card 3020);

3. Determination of purchase price;

4. Verifying that the price has not exceeded the caller's credit line and the like;

5. Receipt of partial invoice from AS 3202;

6. Complete additional fields in the invoice to create a complete invoice;

7. Adding a complete invoice to the billing information memory file 3212 for later processing; and

Send the corresponding commands to the PPV message generator 3210 to generate relevant EMMs.

EMMs are either transmitted on modem line 4002 when a consumer has placed a product order using the receiver / decoder 2020 (more details will be described later) or are transmitted. One exception is when there is some modem connection failure {when the consumer places an order using a receiver / decoder

2020); in these circumstances, the EMMs are airborne.

Subscriber modification required by subscriber includes:

1. Caller identification (using AS 3202);

2. Send information to command interface 3102; wherein said C1 3102 further forwards this information to SMS 3004; and

3. Via C1 3102, the OCS 3207 then receives a response from SMS 3004 (regarding price modification if modification is possible).

If the modification was requested using the decoder receiver 2020, the OCS 3207 generates an acknowledgment to the SMS 3004. Otherwise, for example, in the case of a telephone or MINITEL system, the subscriber is asked for confirmation and this reply is sent to the SMS 3004 via OCS 3207 and Cl 3102.

Parent code reset includes:

1. Caller identification (using AS 3202); and

2. Sending a command to the MG 3210 to generate a suitable EMM message bearing the appropriate reset password.

In the case of a parental code reset, for security reasons, the code reset command is not allowed to come from the receiver / decoder 2020. Such a command can only come from SMS 3004, telephone and MINITEL or the like. Thus, in this particular case, EMMs are transmitted only over the air, never on a telephone (modem) line.

From the above examples of the different modes of operation of the OCS 3207, it should be understood that the user can have direct access to SAS 3002, and in particular to OCS 3207 and AS 3202, by communicating service channels 3022 directly connected to SAS 3002 and more precisely with OCS 3207. This important feature is associated with a reduction in the time it takes a user to transmit his command to SAS 3002.

This feature is further illustrated with reference to Fig. 12, from which it can be seen that the end user set-up control box (STB) and in particular its receiver / decoder 2020 has the ability to communicate directly with the communication service channels 3022 associated with SAS 3002. Instead of making the connection from the end user to the communication service channels 3022 of the SAS 3002 system via SMS 3004, this connection is made directly with the SAS 3002.

In fact, as mentioned above, two direct connections are made.

The first direct connection is through a voice link over the 4001 and a suitable telephone line (and / or MINITEL or similar, where available), while end users still have to enter a series of voice commands or numeric codes, but time is still saved comparison with communication via SMS 3004.

A second direct connection is made from the receiver / decoder 2020 and data entry is achieved automatically by the end user inserting their own daughter smart card 3020, releasing that end user from having to enter relevant data, further reducing the time needed and reducing the likelihood of errors in performing this assignment.

Another important feature that follows from the above description is associated with limiting the time it takes for the resulting EMM to be sent to the end user to initiate tracking of the selected product by that end user.

v. '.

by.

In a broader sense, and with reference to Fig. 12, this feature is again achieved by ensuring that the end-user receiver / decoder 2020 has the ability to communicate directly with communication service channels 3022 associated with SAS 3002.

As described in the foregoing description, the integrated receiver / decoder 2020 is coupled directly to the communication service channels 3022 via a modem return channel 4002 so that commands from the decoder 2020 are processed by SAS 3002, messages (including EMMs) are generated and then sent back directly to When communicating between the CS 3022 and the receiver by the decoder 2020, a protocol is used (as described below) so that the CS 3022 receives an acknowledgment of receipt of the relevant EMM message, adding reliability to the procedure.

For example, in the order mode, the SAS 3002 receives messages from the end user via a smart card and a decoder 2020 via its modem and via a telephone line 4002.

requesting access to a specific event / product, and returning a suitable EMM via a telephone line 4002 and a modem to the decoder 2020, wherein the modem and the decoder are preferably located together in the setup control box (STB). Thus, this is achieved without the need to transmit an EMM in the MPEG-2 data stream via the compressor 2002 and through the multiplexer and encoder 2004, uplink 2012, satellite transponder 2014 and data downlink 2016 to allow the end user to watch the selected event / product. In this way, it is possible to save substantially on the required time and bandwidth. The factual reliability is also assured by the fact that once the subscriber has already paid for their purchase, the EMM arrives at the receiver / decoder 2020.

In the third type of operation mode of the OCS 3207 as described above, the OCS 3207 works with callbacks issued by the SAS 3002 system. This is illustrated with reference to Fig. 13. Typical callbacks are intended to ensure that the receiver / decoder 2020 calls back to SAS 3002 via modem return channel 4002 with the information SAS 3002 requires from receiver / decoder 2020.

As instructed by the command interface 3102, the message generator 3106 in the subscriber chain generates an EMM feedback message and sends it to the receiver / decoder 2020. This EMM message is encrypted for security reasons by the encryption unit 3008. The EMM may contain a time / date at which the receiver / decoder 2020 should activate and make a callback to itself without being explicitly prompted; The EMM may also typically include telephone numbers that the terminal must dial, the number of additional attempts after unsuccessful calls, and the delay between two calls.

Upon receipt of the EMM, or at a specified time-date, the receiver / decoder 2020 connects to the communication service channels 3022. The OCS 3207 first identifies the caller using the AS 3202 and verifies certain details such as the smart card operator and subscriber details. The OCS 3207 then asks the smart card 3020 to send various encrypted information (such as the relevant number of sessions when the session was monitored, how many times a subscriber is allowed to watch the session again, the manner in which the session was monitored, number of usable units remaining, ). This information is decrypted by the PPV string message generator 3210, again using the encryption unit 3008. The OCS 3207 adds this information to the feedback information file 3214 for later processing and forwarding to the SMS 3004. This information is encrypted for security reasons. The whole procedure is repeated until the smart card no longer contains anything to read.

One particularly advantageous feature of this callback arrangement is that before the smart card is read (i.e. immediately after the caller identification using the AS 3202 as described above), the SAS 3002 system checks that the receiver / decoder 2020 is genuine and genuine, rather than being a pirated version or a computer simulation. Such control is performed as follows. The SAS 3002 generates a random number that is received by the receiver / decoder 2020. encrypted and then returned to the SAS 3002. The SAS 3QQ2 decrypts this number. If the decryption is successful and the original random number is obtained, it can be concluded that the receiver / decoder 2020 is genuine, and the procedure continues.

Otherwise, the procedure is interrupted.

Other features that may occur during a callback are deleting outdated sessions on the smart card or filling the wallet (this latter feature is also described in the description below, Smart Card).

Also in conjunction with pay-per-view chain region 3200, a description of communication service channels 3022 is now provided below. At the hardware level, these channels preferably include a parallel DEC Four processor. At the software architecture level, as shown in Figure 14, communication service channels are quite common in many respects.

One particular difference from conventional designs results from the fact that service channels must serve both receivers / decoders 2020 and voice communication with conventional 4001 telephones as well as possibly with MINITEL or similar systems.

In the following description, it will be noted that two command-centered service channels 3207 are shown in FIG.

(such as OCS1 and OCS2). Naturally, any desired number can be used.

The communication serving channels include two main serving channels CS1 and CS2 as well as a number of front serving channels, for example the front serving channels Front 1 and Front 2; whereas, although the figure shows two front service channels, usually 10 or 12 can be provided per main service channel. Also, although the figure shows two main service channels CS1 and

C52 and two front service channels Front 1 and Front 2, any number of these channels could be used. Usually, some redundancy is desirable.

CS1 and CS2 main service channels are connected to 5 command centered OCS1 and OCS2 service channels via 3230 high-level TCP / IP connection, while main services C51 and CS2 are connected to Front 1 and Front 2 front service channels through another 3232 TCP / IP connection .

As illustrated, they include the main service channels

CS1 and CS2 service channels for 3ENDR (transmission), RECVR (reception), VTX (MINITEL, PRESTEL or the like), VOX (voice communication), and TRM 'communication with receiver / decoder). These service channels are connected to the BUS to communicate signals to the front service channels.

The main service channels CS1 and CS2 communicate directly with the receivers / decoders 2020 through their modem return channels 4002 using a common public network pro-X25. The relatively low-level protection between communication service channels 3022 and receiver / decoders 2020 is in one preferred embodiment based on the international CCITT protocol of the V42 standard, which provides reliability by having error detection and retransmission functions and utilizing a checksum program for retransmission integrity check. An escape mechanism is also provided to prevent the transmission of illegal characters.

On the other hand, voice telephony communication is conducted via leading communication service channels, each capable of, say, 30 simultaneous voice transmissions from 3234 connections to the local telephone network via a high-speed T2 (E1) standard ISDN telephone line.

The three specific functions of the software part of the communication service channels (which could, of course, be implemented entirely in hardware) are: first, to change the relatively low-level protocol information received from the receiver / decoder to the information output of the relatively high-level protocol to the OCS; ) or to control the number of concurrent connections, and thirdly to create multiple concurrent channels without any mixing. In this latter aspect, the communication serving channels play a role of a form of multiplexer, wherein the interactions in a particular channel are defined by a given session identifier that is actually used throughout the communication chain.

Finally, as far as the pay-per-view chain area 3200 is concerned, and again referring to Fig. 5, the program transmitter service channel 3208 (SPB) is connected to one or more program transmitters 3250 (which could typically be located remotely from SAS 3002) for receiving program information. SPB 3208 filters information corresponding to PPV events (sessions) for further use.

A particularly important feature is that the filtered program event information 25 is transmitted via SPB 3208 to the MG 3210, which further sends a pseudo instruction (control command) to the ME 3306 or 3308 to change the EMM cycling rate under the circumstances; this is done so that the ME finds all messages

EMM with the relevant Session Identifier and changes the transmission cycle rate assigned to these EMMs. This feature could be understood as dynamic bandwidth allocation for specific EMMs. EMM cycling is discussed in more detail in the description below in the section dealing with the EMM loader.

The circumstances in which the transmission cycle rate is varied will now be described with reference to Figure 15, which demonstrates how the 3252 cycle rate is increased briefly (say 10 minutes) before a particular PPV program event until the end of that event from a slow cycle speeds,

Let's say once every 30 minutes, at a fast cycle rate, say once every 30 seconds or every 1 minute, to meet the anticipated increased user demand for PPV events at these times. In this way, the bandwidth can be allocated dynamically according to the assumed claims of L5 users. This can help reduce overall bandwidth requirements.

The cycle speed of other EMMs may also be varied. For example, the cycle speed of EMMs related to

The subscription 20 may be changed by a multiplexer and an encoder 2004 transmitting a suitable pseudo instruction regarding the bit rate.

EMM loader

With respect to the EMM inserter 3300, details of the message transmitters 3302 to 3308 that form part of the EMM inserter 3300 and act as output means of the message generator will now be described with reference to Fig. 16. Their function is to receive EMMs and transmit them cyclically (in the form of a carousel) via the corresponding links 3314 and 3316 to the software multiplexers 3310 and 3312 and thus to the hardware multiplexers and encoders 2004. In response, the software multiplexers and encoders 2004 create a global bit rate pseudoinstruction to control the overall cycle rate of the EMMs; to do so, ME 3302 to 3308 take into account various parameters such as cycle time, EMM size, and so on. EMM_X and EMM_Y show EMM message groups for X and Y, while EMM_Z are other EMM messages for either X operator or Y operator.

θ Further description proceeds by way of an exemplary embodiment of one of the message transmitters; it should be noted that the remaining MEs work in a similar way. The ME operates under MG pseudoinstruction, which mainly controls the start of transmission and the end time and transmission rate, as well as the session number if the EMM is a PPV EMM. With respect to the transmission rate, in a preferred embodiment, the relevant pseudoinstruction may take one of five values from very fast to very slow. Numeric values are not specified in the pseudoinstruction, but the ME rather assigns θ pseudoinstruction to the actual numeric value that is delivered through the appropriate part of the SAS. In a preferred embodiment, the 5 transmission rates have the following values:

1. very fast - everybody 30 seconds 2. fast - every minute 3. medium - everybody 15 Dec minutes 4. slowly - everybody 30 minutes 5. very slowly - everybody 30 minutes

The ME has first and second databases 3320 and 3322. The first database 3320 is for those EMMs that have not yet reached their broadcast date; these messages are stored in chronological file series in this database 3320. Second database

3322 is for immediate broadcast EMMs. In the event of a system failure, the ME is arranged to be able to re-read the relevant saved file and perform a corrective broadcast. All files stored in databases 3320 and 3322 are updated to MG requests when MG needs to maintain consistency between incoming pseudo instructions and EMMs already sent to the ME. EMMs that are currently being transmitted are also stored in 3324 direct access memory (RAM).

The combination of EIEO memories 3162 and 3164 in the message generator and databases 3320 and 3322 in the message transmitter means that the two components can operate in a stand-alone mode if the link 3166 between them is temporarily broken; The ME can then still send EMMs.

The software multiplexers (SMUX) 3310 and 3312 form the interface between the ME transmitters and the hardware multiplexers 2004.

In a preferred embodiment, each of them receives EMMs from two MEs, although generally there is no limitation regarding the number of MEs that can be associated with one SMUX. SMUXs gather EMMs and then forward them to the appropriate hardware multiplexer according to the EMM type. This is necessary because hardware multiplexers take different types of EMMs and place them at different locations in the MPEG-2 stream. SMUX also transmit global pseudo-instructions regarding bit rate from hardware multiplexers to ME transmitters.

One particularly important feature of ME is that it transmits EMMs in random order. The reason for such an arrangement is as follows. The message transmitter does not have the ability to scan or control the content of what it sends to the multiplexer. Thus, it is possible that it can transmit two EMMs to be received and decoded by the receiver / decoder 2020, in short mode. In such circumstances, it is further possible that if the EMMs are insufficiently separated, the receiver / decoder and the smart card will be unable to read and decode the other of these EMMs correctly. Cyclic EMM broadcasting in random order can solve this problem.

The way in which random distribution is achieved will now be described with reference to Fig. 17; in a preferred embodiment, the necessary software logic is implemented in the ADA machine language. A particularly important part of random distribution is the correct storage of EMMs in databases 3320 and 3322 (which are used for backup purposes) and in RAM 3324. For a particular transmission and operator cycle speed, EMMs are stored in a two-dimensional array via 3330 (going from to Z) and count at 3332 (going from 0 to N). The third dimension is added via the 3334 cycle rate, so that as many two-dimensional fields as used by the transmission cycle rate are created. In a preferred embodiment, 25 is used 256 levels and usually 200 or 300 EMMs in each level; and 5 transmission cycle rates are used. The last dimension of the array is added by the existence of different operators; there are as many three-dimensional fields as there are operators. Storing data in this way can allow for fast retrieval if the MG requests the deletion of an EMM.

EMMs are stored according to a checksum algorithm (otherwise known as a one-way checksum function). It works on a modeling approach, so that successive levels are filled before a higher number is used in the level, and the number of EMMs in each level remains roughly constant. In this example, 256 levels are considered. When the MG sends an EMM with an identifier (ID) of 1 to the ME, this EMM is assigned level 1 and occupies the first number at level 3332 for level 3330. An EMM with ID 2 is assigned level 2 and so on up to level 256.

The EMM with ID 257 is again assigned level 1 (based on the modulo function) and occupies the second number in the first level and so on.

Search for a specific EMM message, for example, when 1 × 5 ^times via MG is required to delete that specific message

EMM, is performed by reversing the above procedure. The checksum algorithm is applied to the ID of the EMM to obtain a level, then a number is found at that level.

The actual random distribution occurs when the EMMs are cyclically released from RAM 3324 using the random distribution means 3340 that is implemented in the hardware and / or software of the message transmitter. The search is direct and again based on a checksum algorithm. First, a random number (in the above example, first in the range of 1 to 256) is selected to determine a certain level to be used. Second, another random number is selected to determine a certain number in the level. This additional random number is selected based on the total number of EMMs at that level. Once the EMM has been selected and transmitted, it is moved to the second identical memory area in RAM 3324 again using the checksum function. Thus, the first area decreases in size as EMMs are transmitted to the extent that when the entire level is used, the area is deleted. Once the first memory area is completely empty, it is replaced by the second memory area before the new EMM broadcasting round and vice versa.

In the above process, after two or three cycles of transmission of the EMMs chances of any two EMMs ¹ 0 intended for the same end user will be transmitted in short, statistically insignificant.

At regular intervals, while the EMMs are stored, the center computer 3050 calculates the number of bytes in memory and calculates from this value the bit rate of transmission given by the global bit rate instruction from the multiplexer and the software multiplexer.

In the above description, backup databases 3320 and 3322 have been mentioned. In fact, these databases are preferably sequential file memories containing a backup version of what is contained in RAM 3324. In the event of a message transmitter failure and subsequent restart, or more generally, when the ME is restarted (restarted) for any reason, a connection is established between the RAM and the databases through which EMMs are loaded into the RAM. This can eliminate the risk of losing EMMs in the event of a system failure.

For PPV EMMs, storage is similar to that described above in connection with subscriber messages

EMM, with the level typically corresponding to the operator and the level number corresponding to the session number.

Smart card

The daughter or subscriber smart card 3020 is schematically illustrated in Fig. 18 and includes an 8-bit microprocessor 110, such as the Motorola 6805 microprocessor, having an input / output bus coupled to a standard contact field 120, which in use is coupled to the corresponding contact field in the reader. a card device in the receiver / decoder 2020, wherein the card reader is of conventional design. The microprocessor 110 is also provided with bus connections with preferably masked ROM 130, RAM 140, and EEPROM 150. The smart card complies with standard protocols ISO 7816-1, 7816-2, and 7816-3, which determine certain physical parameters of the smart card, the position of the contacts on the chip, and certain communications between the external system (and in particular the receiver / decoder 2020) or the smart card respectively and which will therefore not be described in detail in this description. One function of microprocessor 110 is to manage the memory in the smart card as described below.

The EEPROM 150 includes certain dynamically generated operator zones 154, 155, 156 (operator ID) and dynamically generated data zones, which will now be described with reference to FIG. 19.

As shown in FIG. 19, the EEPROM 150 includes a permanent 8-byte permanent card ID (or manufacturer) zone 151 containing a permanent ID of the subscriber smart card specified by the smart card manufacturer.

3020.

When the smart card is reset, the microprocessor 110 outputs a signal to the receiver / decoder 2020, which signal includes the conditional access system identifier used by the smart card and data generated from the data stored in the smart card, including the card ID (identifier). This signal is stored by the receiver / decoder 2020, which then uses this stored signal to check if the smart card is compatible with the conditional access system used by this receiver / decoder 2020.

The EEPROM 150 also includes a random number generator permanent zone 152 that includes a program for generating pseudo-random numbers. These random numbers are used for splitting transactions of output signals generated by the smart card 3020 and sent back to the transmitter.

A 144-byte permanent control zone 153 is formed below the random zone 152 of the random number generator. This permanent control zone 153 is a specific operator zone utilized by the V ROM 130 program to dynamically create (and remove) zones 154, 155, 156 ... as described in more detail below. Permanent control zone 153 contains smart card privileges for creating or deleting zones.

The Dynamic Zone Creation and Removal Program operates in response to specific EMMs to create (or remove) zones that are transmitted by the SAS 3002 and received by the receiver / decoder 2020 and transmitted to the subscriber smart card 3020. operator that specific control keys are to be assigned to the control zone. This prevents one operator from deleting zones related to another operator.

Below the control zone 153 is a series of operator ID zones 154, 155, 156 for operators 1, 2 and N. Typically, at least one operator ID zone will be preloaded into the EEPROM of the subscriber smart card 3020.

Uživatelθ user can decode programs broadcast by this operator. However, additional operator ID zones may subsequently be dynamically created using the permanent control zone 153 in response to the transaction output signal generated via the smart card.

3020 by the end user (subscriber) as will be in more detail

L5, described may.

Each operator zone 154, 155, 156 includes an identifier of the group to which the smart card 3020 belongs and the location of the smart card within that group.

This allows the smart card (along with other smart cards in its group) to respond to the broadcast of a group EMM subscriber having a group address (but not the location of the smart card in the group) as well as individual (or subscription to commercial offers)

2 ^ EMM addressed only to this smart card within the group.

There can be 256 member smart cards in each such group, and thus this feature substantially limits the bandwidth required for EMM transmission.

To further reduce the bandwidth required to transmit EMM group subscription messages, the group data in each operator zone 154, 155, 156 and all similar zones in the EEPROM of the smart card 3020 and other daughter smart cards is continuously updated to allow a particular smart card to be changed. its location in each group to fill any gaps created, for example, by deleting a member of the group. The gaps are filled by SAS 3002. Because there is a list of these gaps in STM server 3104.

In this way, segmentation is severely limited and the number of members in each group is maintained at or near the value of 256 members.

Each operator zone 154, 155, 156 is associated with one or more operator data objects (operator data objects) stored in the EEPROM 150. As shown in Fig. 19, a series of dynamically generated operator data objects 157 to 165 are located below the ID zones operator. Each of these objects is marked with:

a) an identifier i, 2, 3 ... N corresponding to the corresponding operator 1, 2, 3 ... N, as shown in its left part in Fig. 19;

(b) an ID indicating the type of object; and

c) a data zone reserved for the data, as shown in the right part of each relevant operator data object in Fig. 19.

It should be understood that each operator is associated with a similar set of data objects, so that the following description of the data type in the data objects of operator 1 is also applicable to data objects of all other operators. It will also be apparent that the data objects are located in contiguous physical areas of the EEPROM and that their order is not essential.

Deleting data objects creates a gap 166 in the smart card, that is, a certain number of bytes that the previously deleted objects 5 occupied are not occupied now. The number of bytes or space thus released is denoted by:

(a) identifier 0; and

b) ID (identifier) indicating that these bytes

XOs are free to receive an object.

The next data object created fills this gap, which is indicated by the identifier 0. In this way, the limited storage capacity (4 kilobytes) of the EEPROM 150 is effectively used.

If it now relates to a set of data objects associated with each operator, examples of these data objects will be described below.

The data object 157 includes an EMM key used to decode the encoded EMMs received by the receiver / decoder 2020. This EMM key is permanently stored in the data object 157. This data object 157 can be created before the smart card is distributed 3020 and / or can be dynamically created, when a new one is created

2 ^ operator zone (as described above).

The data object 159 includes ECM keys that are sent by the corresponding operator (in this case, operator 1) to allow the end user to decode a particular set of programs to which he subscribed (which he subscribed to). New ECM keys are sent every month together with a ΞΜΜ group subscription (renewal) message that restores the overall end user's right to watch broadcasts from (in this case) the operator 1. Using a separate EMM and ECM keys allows viewing rights to be purchased in different ways (in this case through subscription and individually (pay per view)), and also increases security. Pay Per View Mode (PPV) will be described in more detail below.

Because new ECM keys are transmitted periodically, it is

It is essential to prevent the user from using the old ECM keys, for example, by turning off the receiver / decoder or resetting the clock to expire the old ECM key so that the timer in the receiver / decoder 2020 could be skipped. Therefore, the operator zone 154 includes

L5 area (usually having a size of 2 bytes) containing the date of obsolescence of ECM keys. The smart card 3020 is arranged to compare this date to the current date contained in the received ECMs and to prevent decoding if the current date is later than the date of obsolescence. The obsolescence date is transmitted via EMMs as described above.

The data object 161 includes a 64-bit subscriber bitmap that is an accurate representation of the broadcast programs of the operator to which the subscriber subscribes

5 subscribed. Each bit represents a program and is set to 1 if it is subscribed and to 0 if it is not subscribed.

The data object 163 includes a plurality of units that can be used by the consumer, in PPV mode for purchase, of immediate broadcast viewing rights, for example, in response to free samples or other advertising. The data object 163 also includes a limit value that can be set, for example, to a negative value to allow credit to the consumer. The units may be purchased, for example, by credit and via modem return channel 4002, or, for example, by using a voice service channel in combination with a credit card. A specific event can be billed as a single unit or a certain number of units.

The data object 165 includes a description of the PPV event as shown in reference to the table 167 shown in Fig. 20.

Table 167 describing the PPV event includes session ID 168 identifying the session to be monitored (corresponding to program and time and date of transmission) session mode 169 indicating how purchase watch rights are purchased (e.g., in order mode), session index 171 and session tracking 171 .

With regard to receiving a program in PPV mode, the receiver / decoder 2020 determines whether the program is a program sold in PPV mode. If so, then the decoder 2020 checks, using the items stored in Table 167 describing the PPV event, whether the session ID for this program is stored there.

If the session ID is stored here, the control word is removed from the ECM.

If the session ID is not stored here, then a specific application receiver / decoder 2020 will display a message to the end user indicating that the user has the right to watch the session at the cost of, say, 25 units as read from the ECM or can connect to the communication service channels 3022 to buy the event. When using units, if the end user answers yes (via remote control unit 2026 (see Figure 2)), the decoder 2020 sends the ECM to the smart card, the smart card reduces the purse content in the smart card 3020 by 25 units, writes session ID 168, session mode 169, session index 170, and session tracking 171 into table 167 describing the PPV event, and extracts and decrypts the control word from the ECM.

In the order mode, the EMM will be passed to the smart card 3030 so that the smart card writes the session ID 168, the session mode 169, the session index 170 and the session tracking 171 to the PPV event description table 167 using this EMM.

Session index 170 can be set to differentiate ~

one broadcast from another. This feature allows authorization to be given to a subset of transmissions, for example, 3 times out of 5 transmissions. As soon as an EMM with a session index different from the current session index 170 stored in the table 167 describing the PPV event is transmitted to the smart card, the number of session tracking 171 is reduced by one. When session tracking 171 reaches zero, the smart card refuses to decrypt the ECM with a session index other than the current session index.

The initial value of session tracking depends only on the manner in which the broadcaster wishes to define the event to be observed; session tracking for a given event can have any value.

The microprocessor 110 in the smart card implements a counting and comparison program for detecting when the program monitoring limit has already been reached.

All components of Session ID 168, Session Mode 169, Session Index $ 170, and Session Tracking 171 in Table 167 describing

The PPV event can be removed from the smart card using the reverse procedure as described above.

Each receiver / decoder 2020 includes an identifier that can either uniquely identify this receiver / decoder or identify its manufacturer or classify it in some other way to allow it to work only with a specific individual smart card, a class of smart cards manufactured by the same or the corresponding manufacturer or any other class of smart cards that are intended for use solely with this class of receivers / decoders.

In this way, receivers / decoders 2020 supplied to a consumer by a single broadcasting provider are protected against the use of unauthorized daughter cards 3020.

In addition or alternatively to this first acknowledgment of cooperation between the smart card and the receiver, the EEPROM of the smart card 3020 could include a field or bitmap describing the categories of receivers / decoders 2020 with which it can operate. These categories could be specified either during the production of the 3020 smart card or through a specific EMM.

The bitmap stored in the smart card 3020 typically includes a list of up to 80 receivers / decoders, each identified by a corresponding receiver / decoder ID with which the smart card can be used. Each receiver / decoder is associated with level 1 or 0, which indicates whether or not the smart card can be used with that receiver / decoder. The program in the receiver / decoder memory 2024 searches for the receiver / decoder identifier in the bitmap stored in the smart card. If this identifier is found and the value associated with this identifier is 1, then this smart card is activated, if not, then the smart card will not work with this receiver / decoder.

In addition, if, usually due to an agreement between operators, it is desirable to authorize the use of other smart cards in a particular receiver / decoder, special EMMs will be sent to these smart cards to change their bitmaps via the transponder 2014.

Each broadcaster may differentiate its subscribers according to a predetermined criterion. For example, a certain number of participants may be classified as VIPs. Thus, each broadcaster may divide its subscribers into a number of subgroups, each subgroup

2 includes any number of participants.

A subgroup to which a subscriber belongs is set up in SMS 3004. Furthermore, the SAS 3002 sends an EMM message to the subscriber, which writes information (typically about 1 byte) regarding the subgroup to which the subscriber belongs to the relevant operator data zone, say zone 154. EEPROM in the smart card. Further, as the events are transmitted by the broadcaster, an EMM, typically 256 bits, is transmitted with the event, which EMM indicates which of the subsets of subscribers can follow the event.

If, according to the information stored in the operator zone, the subscriber does not have the event tracking rights as determined by the ECM, program tracking is denied.

This arrangement can be used, for example, to disconnect all of the smart card operator in certain geographical areas during the transmission of a program, especially 0 ¹ program on sporting events taking place in this geographical area. In this way, football clubs and other sports can sell broadcast rights outside their location, while at the same time preventing local fans from watching the event on TV. In this way, local fans are encouraged to buy tickets and attend events.

Each of the features associated with zones 151-172 is considered to be a separate invention independent of dynamic zone formation.

It should be understood that the present invention has been described above purely by way of example, and that modifications of particular details may be made within the scope of the invention.

Each feature described in the description and (where appropriate) in the claims and drawings may be formed independently or in any suitable combination.

In the aforementioned preferred embodiments, certain features of the present invention have been implemented using computer software. However, it will be obvious to those skilled in the art that any of these features can be realized using hardware. Moreover, it should be understood that functions performed by hardware, computer software and the like are performed on or using electrical and similar signals.

At this point reference is made to parallel patent applications of the same applicant having the same filing date and the following titles: generation and transmission of signals (representative mark: 73142 / PT), smart card for use with a coded broadcast signal receiver and receiver (representative mark: 73143 / PT), Transmitting and receiving system and conditional access system (Representative mark: 73145 / PT), Downloading a computer file from a transmitter via a receiver / decoder to a computer (Representative mark: 73146 / PT), Broadcasting and receiving television programs and other data (shortcut tag:

73147 / PT), Method of uploading data to an MPEG receiver / decoder and an MPEG broadcasting system for its implementation (Representative mark: 73148 / PT), Computer memory organization (Representative mark: 73149 / PT), Method of developing and testing a control program (Representative mark : 73150 / PT), Selection of slots from the transmitted data stream (representative mark: 73151 / PT), Access control system (representative mark: 73152 / PT), Data processing system (representative mark: 73153 / PT), Transmitting and receiving system, receiver / decoder and remote control unit (Representative brand: 73154 / PT). Descriptions of these documents are incorporated herein by reference. The list of applications contains the present application.

Claims (7)

PATENT CLAIMS CLAIMS 1. A message set recreating device comprising: means for generating a plurality of messages; means for repeatedly randomizing the order of the messages to form a plurality of sets of such messages, such that the messages of each set are in random order; and output means for transmitting a plurality of message sets. The apparatus of claim 1, wherein the message generating means comprises a memory means for storing the generated messages. The apparatus of claim 2, wherein the random distribution means is configured to generate each set of messages by selecting the messages in random order from the storage means. 4. A device according to claim 2 or 3, wherein the memory means is configured for 2Q storing messages in at least a two-dimensional array. The apparatus of any preceding claim, further comprising means coupled to the output means for varying the rate at which a plurality of message sets are transmitted. A device according to any one of claims 2 to 6 4, further comprising means associated with the memory means for evaluating the size of the messages stored in the memory means, and means associated with the output means for changing the rate at which a plurality of message sets are transmitted depending on said message size. Device according to any one of the preceding claims, characterized in that the formation means 5 and the random distribution means are connected via a first-in-first-out (FIFO) type device. Device according to any one of the preceding claims, characterized in that the outlet 10, the means comprises means for storing at least one of the message sets. The apparatus of any preceding claim, wherein a plurality of output means is provided, and further comprising a multiplexer for receiving a plurality of message sets transmitted by said plurality of output means. 10. An access control system for a transmitting and receiving system comprising: a 2θ at the transmitting end of the device according to any of the preceding claims, and at the receiving end of the device for receiving said messages. The access control system of claim 10, characterized in that said message 25 is an authorization message for transmission to the receiving device. 12. A transmission and reception system comprising an access control system according to claim 11. 13. A method of recreating a set of messages comprising: generating a number of messages; - repeated random distribution of message order for 5 forming a plurality of sets of such messages, such that the messages in each set are in random order; and forwarding a plurality of message sets. The method of claim 13, comprising the step of storing the messages generated in the composing step, wherein in the random distribution step, each set of messages is generated by selecting the messages in random order. A method of controlled user access to broadcast a 25 of a receiving system comprising at the transmitting end a method of re-creating message sets according to claim 13 or 14, and at the receiving end a step of receiving said messages. A method according to claim 15, characterized by 20 -. wherein the message is an authorization message for receipt through the receive step. 17. A device substantially as described and illustrated in the accompanying drawings, in particular in FIGS. 16 and 17 A device according to any one of claims 1 to 18 9, characterized in that the output means is arranged to transmit a plurality of message sets in the form of a digital signal comprising a digital data packet and an identifier for the packet, the identifier having a length of less than two bytes. An apparatus for generating a digital signal comprising a digital data packet and an identifier for the packet comprising 5; means for creating a data packet; and means for generating an identifier; characterized in that: the identifier building means is configured to produce an identifier having a length of less than two bytes. 20. The apparatus of claim 18 or 19, wherein the identifier includes an identity parameter a 15 length parameter. 21. The apparatus of claim 20, wherein the identity parameter and the length parameter each have 4 bits in length. The apparatus of claim 20 or 21, wherein the digital value of the length parameter is not directly proportional to the actual length of the packet. The device of any one of claims 20 to 22. characterized in that it further comprises means for storing a lookup table providing a relationship between the digital value of the length parameter and the actual length of the packet. A transmitting and receiving system comprising at the transmitting end a device according to 24. any of claims 18 to 23 and at the receiving end of a device for receiving said signal. A method according to any one of claims 13 to 25 16, characterized in that a plurality of messages 5 are transmitted in the form of a digital signal comprising a digital data packet and an identifier for the packet, the identifier having a length of less than two bytes. A method for producing a digital signal comprising 10 is a digital data packet and an identifier for the packet, the method comprising: creating a data packet; and creating an identifier; characterized in that: The identifier has a length of less than two bytes. 27. The method of claim 25 or 26, wherein the identifier includes an identity parameter and a length parameter. The method of claim 27, wherein the digital value of the length parameter is not directly proportional to the actual length of the packet. A digital signal comprising: a digital data packet; and 25 identifier for this packet; and characterized in that: the identifier is less than two bytes in length. 30. The signal of claim 29, wherein the identifier includes an identity parameter and a length parameter. The signal of claim 30, wherein the identity parameter and the length parameter each have 4 bits in length. 32. The signal of claim 30 or 31, wherein the digital value of the length parameter is not directly proportional to the actual length of the packet. 33. A device substantially as described and illustrated in the accompanying drawings, in particular in FIG. 10. A transmission and reception system according to claim 1 12, further comprising means for transmitting data and means for generating a control command representative of the data characteristic, the output means comprising retransmitting a plurality of variable repeat rate message sets and changing said repeat rate in response to the control command. 35. A broadcast system comprising: means for transmitting data; means for generating a control command representing data characteristics; and means for retransmitting a variable rate message; said transmitting means for transmitting the message being arranged to change the repetition rate in response to the control command. 36. The system of claim 34 or 35, wherein the data is signals representing program events, and the means for generating a control command is arranged to produce a command representing the transmission time of a particular program event. 37. The system of claim 36, wherein said transmitting means for transmitting messages is configured to change the repetition rate near the event transmission time. 38. The system of claim 36 or 37, wherein said transmitting means for transmitting The IQ message is arranged to increase the repetition rate before the event transmission time. 39. The system of claim 36, 37 or 38, wherein said transmitting means for transmitting messages is arranged to increase 15 repetition rate during the event transmission time. A transmitting and receiving system comprising at the transmitting end a system according to any one of claims 35 to 39 and at the receiving end of the device. 2Q for receiving broadcast data and messages. 41. A method of broadcasting comprising: data transmission; generating a control command representing 25 data characteristics; and retransmitting a message at a variable rate that varies in response to the control command. 42. The method of claim 41, wherein the data signals represent a program event and the control message represents the transmission time of a particular program event. 43. The method of claim 42, wherein the repetition rate varies near the event transmission time. 44. The method of claim 42 or 43, wherein the repetition rate is increased before the event is transmitted. The method of claim 42, 43 or 44, wherein the repetition rate is increased during the event transmission time. 46. A broadcast system substantially as described and illustrated in the accompanying drawings, in particular in FIGS. 5 and 15. 47. A conditional access system for providing conditional access to subscribers, comprising: participant management system; and a subscriber authorization system coupled to the subscriber control system, said authorization system including means for generating subscriber refresh commands and means for authorizing subscriber refresh depending on the commands. 48. A conditional access system for providing conditional access to subscribers, comprising: a subscriber control system for managing subscribers, including a subscriber information database and means for generating a stop command that a particular connection is to be stopped; and a subscriber authorization system for authorizing subscribers coupled to the subscriber control system and configured to 5 receiving a stop command; wherein said subscriber authorization system comprises means for generating a subscriber renewal command for each subscriber depending on the stop command for that subscriber, and means for authorizing subscriber renewal according to the subscriber 10 on subscription renewal orders. 49. The conditional access system of claim 48, characterized in that the subscriber control system comprises means for generating a start command that a connection is to be initiated, and the means for generating subscriber renewal commands of the subscriber authorization system is arranged to generate each subscriber renewal command further depending on the start command. The conditional access system of claim 47, 48 or 49, wherein the subscriber authorization system comprises a subscriber information database. 51. The conditional access system of claim 48 or 2 5 49, characterized in that the subscriber authorization system comprises a subscriber information database and means for updating information in that database as a function of the information in the subscriber control system database. A conditional access system according to any one of claims 47 to 51, characterized in that a device of the type 5 first in first first out (FIFO). 53. The conditional access system of any one of claims 47 to 52, wherein the means for authorizing renewal includes output means for transmitting the authorization entitlement messages to subscribers. 54. The conditional access system of any one of claims 47 to 53, wherein the subscriber authorization system is capable of providing special rights to new subscribers. A conditional access system for a transmitting and receiving system, comprising at the transmitting end a system according to any one of claims 47 to 54, and further comprising at the receiving end a device for receiving said messages. 56. A transmission and reception system comprising a conditional access system according to any one of claims 47 to 54. 57. A conditional access system substantially as described herein and illustrated in the accompanying drawings, in particular in Fig. 5, Fig. 6 or Fig. 7.