MXPA05006345A

MXPA05006345A - Method for access control in digital pay television.

Info

Publication number: MXPA05006345A
Application number: MXPA05006345A
Authority: MX
Inventors: Dauvois Jean-Luc
Original assignee: Canal Plus Technologies
Priority date: 2002-12-17
Filing date: 2003-12-16
Publication date: 2005-08-26
Also published as: WO2004057871A2; CN1726714A; EP1574059A2; AU2003302182A8; FR2848764A1; KR20050090399A; AU2003302182A1; WO2004057871A3; BR0317347A; JP2006510323A

Abstract

The invention concerns a method for controlling access, in digital pay television, to data contained in the signal received by a subscriber receiving station (21) comprising steps which consist in transmitting first right allocation control messages (ECM) enabling proposal to subscribers of an on-demand operation mode and second right allocation management messages (EMM) to a user device (26), generating in the user device an access authorization signal (CW), wherein first right allocation control messages are transmitted having a parameterable profile content enabling at least one service or one programme to be authorized during a time slot based on the profile of a specific subscriber, so as to ensure an interactivity between the content of said first messages and the content of the user's device in terms of subscription for the subscriber.

Description

METHOD FOR THE CONTROL OF ACCESS IN DIGITAL TELEVISION OF PAYMENT TECHNICAL FIELD The present invention relates to a method for access control in the pay digital television field.

DESCRIPTION OF THE PREVIOUS TECHNIQUE The techniques used in pay television are based on two independent mechanisms: on the one hand, in a mixture / encryption of video and / or audio signals, on the other hand, in a function of commercial authorization which is transmitted as security messages to a decryptor module (with control access). Encryption can be easily applied to a stream of digital bits. All bits can be encrypted using, for example, a block cipher. Encryption is used for analog transmissions. Using such a decryption method, the signal format is changed, the synchronization signals are erased and transmitted separately in an encrypted form. The audio signal can be converted into a digital signal after being encrypted. The encrypted digital audio signal can be inserted into the video signal. The transmitted data is mixed or encrypted using a control word ("CW") or a key. The control word or password changes after a short period. To send new keys to the station that the subscriber receives, authorization control messages (ECM) and authorization management messages (EMM) are used. These two messages, ECM and EMM, can be sent through the station that receives the subscriber to a smart card. The ECM messages contain information, which allows the station receiving the subscriber to decrypt the video and / or audio signals. The decryption data is returned to the latter in a way that allows decryption only if the user is authorized to access the current television program. When a user is represented by a smart card, access authorization is indicated by the title data stored on said card. EMM messages contain information that can be used to update the user's title data.

For example, modifying the data stored on the smart card. The ECM and EMM messages have a digital signature field, which ensures the integrity of the message (for example, a Hash code). This prevents users from being able to modify the content of their messages. An ECM message is transmitted with the transmitted encrypted signal. This comprises three fields. The first field contains the access parameters. These parameters define the conditions under which access to the television program is allowed. This field makes possible, for example, an affine evaluation (an additional personal identification code is then required by the decoder) and a geographical masking (a film may not be available in all European countries.) The second field contains a control word in encrypted form The last field contains a data integrity check An EMM message usually contains four fields Each EMM message begins with an address field to select a receiver or receivers There are two address modes, one for the individual station and the other for a group of such stations The second field contains an authorization for a given user The third change contains the service keys in an encrypted form The last field contains a check for data integrity. The EMM messages can also be used to send a command to the decoder. The result of an explicit request from the user to the service provider. These messages are usually individual. EMM messages are not transmitted synchronously with the television service to which they apply. They are transmitted in advance, in order to allow an authorized user to have access to a given program. Any network can be used to transmit these messages to the receiver; the mail or broadcast modem. To increase the probability that an EMM message has been received by the user, to renew a subscription, for example, the last one is sent several times. EMM messages are thus organized cyclically, according to a given period for transmission. The duration of such a period is the main parameter for determining the maximum waiting time to obtain an authorization for a user who has disconnected his receiving station for a long time. A prior art article, entitled "Functional model of a conventional access system" (8301 EBU Review Technical, 1995, No. 266), describes a functional model of a conditional access system for use in digital television. Such a conditional access system comprises a combination of mixing and encryption to prevent any unauthorized reception, mixing makes it possible to make images, sound and unintelligible data, encryption protects the secret codes that have been transmitted with the mixing signal, in order to allow the decryptor to work. After deciphering, any flaw in the images or sound must be imperceptible; it is said to you conditional access system must be transparent. The generation, transmission and use of authorization management messages (EMs) by the subscriber authorization system are illustrated in the single figure. The subscriber authorization system (SAS) and a control word generator (CW) are connected to an operator transmission station 12, each by means of an encryption circuit, 13 and 14. This transmission station of the operator 12, receives image signals I, sound signals S and data signals D, which travel successively through a multichannel 15, a mixer 16, a modulator 17 and a transmitter 18. When receiving the signals transmitted by said transmitter 18, or transmitted, for example, by means of a satellite 20, the station 21 receiving the subscriber, which successively comprises a receiver 22, a demodulator 23, a mixer 24, a demultiplexer 25, delivers image signals I ', signals of sound S 'and data signals D'. A conditional access subsystem, for example, a smart card 28, which comprises two description circuits 27 and 28, and a security processor 29 (secret codes) is connected to this station 21 that the subscriber receives. The decryption requires the possession of a decryptor, a decryption circuit and a current service key. The description requires the use of authorization management messages (EMMs) for the current program, which usually use secret keys stored in the smart card 26. In the field of digital television, a demand mode of consumption can be offered to consumers. Subscribers This consumption mode can be used to view a service, for example, show a movie, in the subscription mode with a reservation shown in an operation of the type of "payment required per view / payment per time". But such a consumer payment can not be used to obtain promotion offers directly to a subscriber, or even authorize a service in an objective way, for example to watch a given movie during a certain time window, according to the profile of a subscriber determined, in order to address a certain section of a subscriber, population, without having to send validation after the authorization management messages (EMM) of devalidation The object of the invention is to solve such problem by providing a new mode of consumption, which makes it possible to authorize a service in an objective manner, and remotely, according to a given subscriber profile, without placing any severe restrictions on the operator's transmission station.

SUMMARY OF THE INVENTION Therefore, the present invention provides a method of controlling access, in digital pay television, for the information contained in a signal received by a station that receives a subscriber, this method comprises the steps of: transmitting two types of messages, by means of this station that receives the subscriber, to a user device, first the authorization control messages that contain the information to allow this station that receives the subscriber, decode the signal and offer the subscribers a method of operation, upon request, second authorization management messages, which contain information to allow updating of the user's authorization data; generating in the user's device an access authorization signal, to allow the decoding of said signal by the station that receives the subscriber, if the user is authorized to access the information contained in the latter, Characterized because the messages of the first mode are transmitted with a programmable profile content, making it possible to authorize at least one service or a program during a certain time window, according to the profile of a given subscriber, in order to produce a certain interactivity between the content of These first messages and the content of the user's device, in terms of subscription for the subscriber. The method of the invention advantageously makes it possible to: - make promotion offers, with a reduction in the number of authorization handling messages (EMM) transmitted; carry out a "profile" (taking into account the profile of the subscriber) easily; - fight against piracy. This method makes it possible, specifically, to fight against a certain type of system piracy, which consists, for a given subscriber, at a certain moment, in the request for a maximum subscription offer after receiving the validation authorization management message. (EMM), which requests the base subscription, while blocking the subsequent authorization management messages (EMM), which include, in particular, the EMM cancellation message.

BRIEF DESCRIPTION OF THE DRAWINGS The only figure illustrates a prior art digital television signal transmitting system.

DETAILED DESCRIPTION OF PARTICULAR MODALITIES In the method of the invention, which operates in a system, as illustrated in the figure, the authorization control messages (ECM) have a programmable profile content, which is used to produce certain interactivity between the content of such ECM messages and the content of the smart card, in terms of subscription for the subscriber. It is thus possible for the subscribers the benefit of a first offer 01 and a second offer 02, to be able to benefit from a third offer 03, under the control of ECM messages, for the duration of a movie, for example. If it is later desired to no longer make such a promotion offer, the condition of the ECM messages is removed. Such a feature allows a view of certain services, according to the profile of the subscribers, without having to send a large number of EMM authorization management messages first. It also makes it possible to ensure that subscribers have a certain benefit profile of a reduced price. For example, a subscriber who has paid for authorizations of the Pl and P2 programs and a commercial offer 01, can pay a program for sale with two tokens or coupons, while the other users have to pay four tokens or coupons. Such a feature also makes it possible to fight against system piracy. According to the method of the invention, a daily temporary offer is assigned for each service or each program. When a subscriber requires access to a program, for example, a movie shown, rather than having access to its permanent offer, this provides access to a temporary offer. Thus, if, after a short time, for example the same day, this subscriber requires a maximum subscription offer, then he makes a change in his mind and, in order not to pay, requests the basic subscription, usually he will send a EMM authorization handling cancellation message. If the latter then uses a "blocker" of these EMM messages, to block the latter, he can then continue to access the required service or the required program exempt from charges for two months, for example. On the other hand, with the method of the invention, since the offer is temporary, the following day, for example, the subscriber will no longer have access to the service, or to the program, even if he has used an "EMM blocker". For subscribers who have requested and confirmed their maximum offers, however, it is necessary to send an EMM cancellation message with the permanent offer of this service, or of this program.

Exemplary Modality of the Method of the Invention with conditional contents Such conditional contents of the EMM messages make it possible to work using the functions AND, OR, IF, ELSE and NOT (AND, OR, IF, ALSO and NOT) or the map fields of bits, which represent the geographical address and / or address of the subscription. They also make it possible to produce a conditional operation between the numbers of the program, for example, a purchase of a program, or another program that has already been purchased. Such conditional operation mode appears in the form of a sequence, for example. YES (offer 01) Y (offer 02) Y (NO offer 03) The purchase program Pl in the "payment required by sight" mode offered for 50 coupons. ALSO Purchase program Pl in the "payment required by view" mode offered by 70 coupons ALSO Purchase Program Pl, in the "payment required by view" mode, offered for 70 coupons. END .with conditional bitmap Conditional mechanisms can be used to offer a subscriber an additional purchase of vision possibilities, for example. YES (((offer 01)? (/ Offer 03) O (offer 04))) OR (offer 02)) Vision of a possible program. END .with fight against system piracy Conditional mechanisms can be used to fight against the aforementioned type of piracy, for example: on the day SI ((temporary offer 05) 0 (permanent offer 01)) see a possible program - END - on the day up to +1 ((temporary offer 06) 0 (the permanent offer see this possible FIN program.

Claims

CLAIMS 1. A method of controlling the access, in pay digital television, to the information contained in a signal received by a station that receives a subscriber, this method includes the steps: of transmitting two types of messages, through this station receiving the subscriber, to a user device, first authorization control messages (ECM), containing information, to allow this station receiving the subscriber to decode the signal and offer the subscribers a mode of operation, upon request, second authorization management messages (EMM), which contains information to allow the updating of user authorization data; to generate, in the user's device, an authorization signal (C) of the access, to allow the decoding of said signal by the station that receives the subscriber, if the user is authorized to access the information contained in the latter, characterized because the first authorization control messages (ECM) are transmitted and have a programmable profile content, which make it possible to authorize at least one service or a program, during a certain time window, according to the profile of a given subscriber, with In order to produce a certain interactivity between the content of these first messages (ECM) and the content of the user's device, in terms of subscription for the subscriber.
2. The method, as claimed in claim 1, wherein the user's device is a smart card.
3. A method to control the access, in digital television by pay, to the information contained in a signal received by a station that receives the subscriber, this method includes: a transmission of the two types of messages, by means of this station that receives the subscriber, to a user device, first authorization control messages, containing information to allow through the station receiving the subscriber, to decode the signal and propose to the subscribers to decode the signal and offer subscribers a mode of operation at your request, second authorization management messages, which contain information to allow updating of the user authorization data, At least one of the first authorization control messages has a programmable profile content, which makes it possible to authorize at least one service or a program, during a certain time window, according to the profile of the determined subscriber, in order to to produce some interactivity between the content of these first messages and the content of the user's device, in terms of subscription for the subscriber.
4. A method for controlling the access, in digital pay television, to the information contained in a signal received by a station that the subscriber receives, this method comprises: reception in a user's device, by means of the station that receives the subscriber , of two types of messages: first authorization control messages, which contain information to allow the station receiving the subscriber to decode the signal and propose to the subscribers to decode the signal and offer the subscribers a mode of operation, to their request, second authorization management messages, containing information, to allow updating of the authorization data of the user, generation in the user's device of an access authorization signal, to allow the decoding of said signal by the station received by the subscriber, if the user is authorized to access the information contained in the last ma; At least one of the first authorization control messages has a programmable profile content, which makes it possible to authorize at least one service or a program, during a certain time window, according to the profile of a given subscriber, in order to to produce some interactivity between the content of these first messages and the content of the user's device, in terms of the subscription for the subscriber.
5. A system for controlling the access, in digital television by payment, to the information contained in a signal received by a station that the subscriber receives, this method comprises: an operator transmission station, to transmit two types of messages, by way of this subscriber station, to a user device, first authorization control messages, which contain information to allow this station receiving the subscriber, decode the signal and propose to the subscribers to decode the signal and offer the subscribers a mode of operation, on request, second authorization management messages, containing information, to allow updating of the user authorization data, at least one of the first authorization control messages, having a programmable profile content, makes possible authorize at least one service or program, during a certain window of time, according to the perf il of a given subscriber, in order to produce some interactivity between the content of those first messages and the content of the user's device, in terms of subscription for the subscriber.
6. A system for controlling access, in digital pay television, to the information contained in a signal received by a station that receives the subscriber, this method comprises: at the subscriber station, a user's device, which receives two types of messages : first authorization control messages, containing information to allow this station receiving the subscriber to decode the signal and propose to the subscribers to decode the signal and offer the subscribers a mode of operation, upon request, second authorization management messages , which contain information to allow updating of the authorization data of the user, on the user's device, a subsystem of conditional access, which allows the generation of an access authorization signal, to allow the decoding of said signal by the station received by the subscriber, if the user is authorized to access the information In the last, at least one of the first authorization control messages, has a programmable profile content, which makes it possible to authorize at least one service or a program, during a certain time window, according to the profile of a subscriber determined, in order to produce a certain interactivity between the content of these first messages and the content of the user's device, in terms of the subscription by the subscriber.