MXPA98005517A - Digital coupons for television of p - Google Patents

Abstract

Selectively transmitted, for promotional purposes, digital coupons in a communication network to the subscribers' terminals. Subscribers automatically receive coupon credits when they satisfy or cover the previously established conditions of the digital coupons. In particular, pay-per-view programming, free programming or reduced-price programming can be provided when a subscriber acquires a given number of pay-per-view programs at a regular price. The terminals maintain an updated balance of the coupon credits available and inform the subscriber, via a user interface, of the available balance. Subscribers can be rewarded by giving them coupons for viewing commercial messages and coupons can be redeemed immediately by pay-per-view programs. With an optional feedback capability, data can be retrieved from the terminal's usage pattern and analyzed by program service providers to determine the effectiveness of promotions and to gather other demographic and individual data. The integrity of the scheme is ensured with encryption techniques

Description

DIGITAL COUPONS FOR PAY TELEVISION BACKGROUND OF THE INVENTION The present invention relates to communications networks, such as cable television, satellite television and computer networks in which services are available for the payment of a fee. In particular, an apparatus and method are presented to allow users of services, such as pay television, to obtain credits when they watch particular programs. The invention allows service providers to transmit credit information in the form of "digital coupons" to the terminals of individual subscribers to promote particular programs and reward spectator constancy. Satellite and cable television networks are well known where video services are available for a fee. Also known are computer network services such as CompuServe, Prodigy, America Online, Knight-Ridder Information Service and others, where you can have access to databases, banking and purchasing services and can communicate email and similar, all for a fee. In the past, some networks have provided services based on a free trial. For example, during promotional periods P1449 / 98MX that last one or two days, for example, improved programming services such as movie channels or sports, can be seen by subscribers who would normally have to pay an additional fee to receive this programming. In most cases, this is done by placing the full service in the? Class class of promotional coding mode where the programs are not encrypted, that is, clean, or using fixed keys that are known for all the terminals the subscribers. For example, in a broadcasting environment, service providers do not know which existing customer or new potential customer is trying to access a particular service. Even if you could have a feedback, for example, using a telephone line or an upstream route, there would be too many customer transactions going in and out of services for the service provider to analyze them in a useful way. Consequently, the service should usually be placed in a coding mode that allows free access by anyone, including new potential customers and even existing clients, or at least a defined large group. In addition, a prolonged period of free service time is usually necessary to effectively promote services, since P1449 / 98MX different programs that are made available during the free preview will attract different interest groups, both demographic and by age of the viewers. For example, some viewers may prefer to watch action movies, while others prefer to watch comedies. In this way, it is necessary to provide a wide variety of free programming over an extended period of time to effectively encourage viewers to subscribe to the enhanced programming services for an additional, monthly fee. During the free advance period, renewal fees and new subscriptions can be reduced to further motivate the client, since the client can otherwise wait until after the free advance period to order the new services that, to In turn, they can overload the call handling capacity of the service provider's subscription center. Additionally, several programs can be offered on a pay-per-view basis (PPV), individually or a la carte, where the subscriber pays a fee to view an individual program. The customer can either call the subscription center in advance to have a specific authorization or authorization for an individual program to be sent to the customer's terminal, or the customer P1449 / 98MX can arrange to have a certain amount of monetary credit, downloaded to the client's terminal. With the selection of the PPV program, the amount of pre-paid credit in the terminal is reduced. This PPV can be offered in fixed times or alternating times with the so-called Next Video on Demand (NVOD, for its acronym in English Next Video On-Demand)). Also, the programs can be distributed essentially immediately with the Video on Demand (VOD, for its acronym in English). In systems with VOD system, the program can be distributed on request to a specific subscriber when that subscriber communicates a purchase signal to a video server located in a main section of the cable television system. The purchase signal can be communicated, for example, through a channel available upstream in a cable television network, or via a telephone line. Several marketing techniques have been used to encourage subscribers to purchase pay-per-view programs. The PPV is usually more profitable for the service provider than the subscription services. These marketing techniques include providing the subscriber with a credit in their monthly report, when the subscriber acquires a predetermined number of PPV programs, or spends a predetermined amount of money in P1449 / 98MX PPV programs. 0 a paper coupon can be sent to the subscriber, which the subscriber can later send by mail to the network billing department to obtain a discount after the subscriber has covered the pre-conditions for the reimbursement of the coupon. For example, the paper coupon may authorize the subscriber a credit of half the price of a PPV program when a PPV program is purchased at the regular price. While these marketing techniques can be effective, some subscribers may become accustomed to receiving paper coupons and other discounts on their monthly report and then may object to paying higher fees when these discounts are not offered. In other words, they will only buy if they get a coupon. It would be desirable to reward subscribers after they have covered some predetermined conditions. Additionally, it is not easy to selectively select groups of subscribers or individual subscribers, without doing the full, free service or inspecting the effectiveness of these promotions. In addition, the effectiveness of conventional promotions can be reduced because the discounting by the subscriber is delayed, typically for a number of weeks due to delays in the billing cycle. Additionally, P1449 / 98MX paper coupons are difficult to organize and manage and are easily lost. Accordingly, it would be desirable to provide a method and apparatus for allowing selective selection of programming service promotions to particular subscribers or groups of subscribers without placing services in the free mode, or using paper coupons. The system must allow subscribers to receive an immediate credit when a predetermined pattern of use has been covered. The system must reward the subscriber's record and encourage subscribers to purchase additional program services, such as PPV programs and / or additional service levels, such as enhanced programming services. The system must also organize the credits in a way that allows the subscriber to take a quick inventory and must inform the subscriber when a service is available through the promotion. The system should allow flexibility as to how the credits can be used, for example, with respect to the variety of shows, times and dates in which the programming can be accessed. In addition, it would be desirable to provide a system to inspect the success of these promotions, obtain feedback on TV usage habits by P1449 / 98MX part of the subscriber and determine the audience (for example, the size of the audience) - of the particular programs. The system must employ cryptographic techniques to frustrate unauthorized persons (eg, pirates) who attempt to tamper with the system for illicit gain. The present invention provides a system having the above and other advantages.

SUMMARY OF THE INVENTION According to the present invention, an apparatus and a method are presented to allow users of services such as pay television to obtain credits when they watch particular programs. The invention allows program service providers to transmit credit information in the form of "digital coupons" to the terminals of individual subscribers to promote particular programs and reward spectator constancy. A communication system according to the present invention includes a controller for transmitting the program services to a plurality of subscriber terminals via a communication channel. The program service may include television programs that are broadcasted or transmitted continuously in a program P1449 / 98MX default, pay-per-view programs that require the specific selection of the user and either a purchase made locally or remotely, the next video on request, which is a payment per event offered at alternate moments of the Broadcasting, and on-demand video services, are transmitted only in response to a user's request, or other electronic information such as computer programs. The communication channel can include a cable plant and / or a satellite link, by way of example, program services can be selectively retrieved by subscriber terminals, for example, a subscriber can select to view a program in particular, by entering the corresponding channel using an on-screen interface, for example, the electronic program guide (EPG, for its acronym in English), and a remote control unit, or by transmitting a purchase order for either PPV or on-demand video programming The controller can distribute the digital coupon information in the terminals together with the program service data using any available technique, such as multiplexing by frequency or time. digital allows -.- terminals to obtain credits when they recover programs P1449 / 98 X, as defined by the preconditions of the digital coupon information. For example, the subscriber can receive a credit for a free PPV program when the precondition of purchasing five PPV programs at regular price has been met. The terminal automatically tracks the balance of the coupon credits as the coupons are awarded and reimbursed. The credits are usable in obtaining services from programs at a reduced charge (for example, at a discount or free). Each terminal includes a processor that inspects a usage pattern (for example, usage history) of the terminal to determine if the preconditions of the digital coupon information have been met. For example, the usage pattern may indicate that the programs have been retrieved by the terminal within the last month, or some other period, or the length of time that would be a particular program, or program service (eg, channel). The terminal can simply grant coupons based on the acquisition of a PPV program, or based on the amount of time spent watching a commercial. The keys are granted in this way when there is a correlation between the usage pattern and the preconditions of the digital coupon information. A user interface such as a graphical user interface (for example on-screen display) P1449 / 98MX can be provided to allow the subscriber to selectively reimburse the credits.For example, the user may have a variety of options from which he chose, where a cash balance and / or a coupon balance are refunded in whole or in parts. The user interface can also be used to obtain a confirmation of the user's involvement, for example, to verify that the user is still viewing a program, it may be periodically required to provide some kind of control input as the program is displayed. When program services include individual programs that can be recovered individually by the terminals, such as a PPV scheme, the credits of the coupons are granted as when the usage pattern indicates that a terminus has recovered a particular number of these individual programs, or a particular amount of charges. This allows a coupon credit to be granted, if one has had access to a PPV program. One or more coupons can be reimbursed in order to have access to a program. To allow program service providers and advertisers to obtain and analyze terminal usage data, a use pattern accounting center that is associated with a network controller can be provided. The accounting center of P1449 / 98MX usage pattern can receive the terminal usage pattern data via a communication link, such as an upstream path in the channel on which the services of the programs are transmitted, or a telephone network. This is especially useful for determining the audience of ads or commercials, where the cost of running the ad in a program is often a function of the estimated video audience. Additionally, the network controller can control the distribution of the information of the digital coupons to the terminals based on the data received from the usage pattern. In this case, the network controller can distribute the digital coupons directly to the terminal in a similar manner as with other authorizations such as subscription authorizations, PPV authorizations, and credit information. For example, subscribers who demonstrate a preference for sports programs may receive information from digital coupons that provide discounts for future special sports events. The controller can thus distribute different information of the digital coupons to the different terminals of the subscribers, based on the usage pattern data or other demographic or individual data that have been compiled by other means. The P1449 / 98MX information from digital coupons can provide different preconditions to obtain the same credits, or the same preconditions to obtain different credits. For example, it is possible to reward favored subscribers such as those who acquired relatively more programming by providing favored subscribers with more coupons than other less favored subscribers, when the conditions of use are met. Various cryptographic techniques can also be used to prevent unauthorized access to digital coupons. A corresponding subscriber terminal and method are also presented.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram of a communication system according to the present invention. Figure 2 is a block diagram of a subscriber terminal according to the present invention. Figure 3 is a block diagram illustrating a decryption hierarchy for use in accordance with the present invention.

P1449 / 98 X Figure 4 is an on-screen display for a user interface in accordance with the present invention. Figure 5 is another on-screen display for a user interface according to the present invention. Figure 6 is still another on-screen display for a user interface in accordance with the present invention. Figure 7 is a flow chart illustrating a method for providing digital coupons in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION A method and apparatus are presented to allow users of program services, such as television, to pay for credits when viewing particular programs. The invention allows the program service providers to transmit the credit information in the form of "digital coupons" to the terminals of the individual subscribers to promote the particular programs and reward the constancy of the viewer. The digital coupons can be generated locally in the terminals based on the criteria sent by the service providers, or P1449 / 98MX transmits indirectly as an authorization by the service provider. Figure 1 is a block diagram of a communication system according to the present invention. The system includes a transmission end, generally shown at 110, a channel 120, and a receiving end, generally shown at 130. The television end 110 includes a central controller 130 communicating with a command processing function of PPV 115, an accounting function of the usage patterns data in terminals 125, an encryptor / multiplexer / modulator 150, a function of the information of the digital coupons 135, a function of the data of the program services 140, and a function of the control data 145. The receiving end 130 includes a number of terminals including terminal 1 (160) to terminal N (170), which receive information from the digital coupons, data from the program services , and control data via a connection port 124 and route 122. Each terminal has an associated display such as a television to display the program service data. For example, "terminal N" 170 has an associated display 180. In the example shown, terminals 160,. . ., 170 are able to communicate with P1449 / 98MX the PPV command processing function 115 and the usage pattern data accounting function 125 via channel 120. For example, in a cable television network, this upstream communication can be provided on a channel (for example, RF spectrum) that is separated from the channels on which the program service data is communicated. A frequency division multiplexing end can be used to achieve this goal. Alternatively, a time division multiplexing scheme, or terminals 160, can be used. . . 170 may communicate with the PPV command processing function 115 and the usage pattern function 125, via a separate communication link such as a telephone network. Furthermore, as discussed in greater detail below, the present invention can be implemented without the function of processing the PPV commands and / or the function 125 of accounting for the usage pattern. The channel 120 can comprise coaxial cable, fiber optic and / or a wireless link -.tal as a satellite or broadcast link. The transmission end 110 of the system can be a main section or RF section of the cable television system, a satellite link center, a broadcasting center, in a manner Example P1449 / 98MX. The function 135 of the digital coupon information comprises a memory for storing the information of the digital coupons according to the present invention. The information of the digital coupons communicated by terminals 160,. . . 170 at the receiving end 130 of the system. In addition, when terminals 160,. . . 170 are addressable, the information of the digital coupons can be directed to the individual terminals and / or to the groups of terminals, for example, according to the demographic data. Alternatively, the information of the digital coupons of a route that is separated from that of the program services can be transmitted. _ The digital coupon information provides the credits that the terminals can use for a number of purposes. For example, the information and digital coupons can provide a discount when the terminals order one or more PPV programs through the PPV order processing function 115. As an example, if a terminal orders five PPV programs within a normal billing site, the digital coupon credit may allow the terminal to order a sixth PPV program without a charge. 0, for signals that order PPV programs infrequently, the P1449 / 98MX digital coupon credit can allow the terminal to order a PPV program at half price. The digital coupon can be generated automatically based on the program's coupon criteria, established by the service provider. This has the advantage of not requiring direct involvement by the service provider. This is also suitable for broadcasting environments where the return path does not exist, is slow, or is not established for interactive transactions. Alternatively, digital coupon information allows terminals to access enhanced program services at a reduced charge, or at no charge, that allows terminals to access other information, such as a computer program, or computer game, an electronic book, a musical composition, a guide to on-screen television programs, reviews of restaurant films, or other information or educational material, for example, information on digital coupons may allow a terminal access ~ an enhanced movie channel for two days with each PPV purchase, or download a computer video game, or earn one hour of free time connected to a computer database. use like this in P1449 / 98MX is hereby intended to cover television, multimedia, and other audio and / or video signals as well as computer programs or virtually any other information that can be accessed and / or communicated by the terminals via the channel 120. The term "credit" is used herein to indicate that terminals are disproportionate with a benefit such as a reduced or deferred charge when they access and / or obtain program services via the channel that is distributed to the subscriber by another medium (for example, mail). Terminals 160,. . . 170 do not realize the credit that is offered with the digital coupon information until the terminals cover certain preconditions. Each terminal includes a means to inspect several factors that define the terminal usage pattern data during a predefined time, including, for example, the number of purchased PPV programs, the number of PPV charges, either, and for what duration, the terminal has been tuned to a particular program or program service, if the terminal has recently updated one or more enhanced program services and if a promotional period is in effect. The promotional period may apply to individual terminals, such as those of new subscribers, or selected groups of terminals, or to all P1449 / 98MX terminals. Therefore, an inspection means in the terminals inspects the above factors to determine if the use pattern of the terminal corresponds to the preconditions of the digital coupon information. Optionally, in a "return or report return" function, the usage pattern data is periodically transmitted from the terminals to the function 125 of accounting for the usage pattern data, for example, via the correction mouth 124 and channel 120, or alternatively, a telephone network. For example, the usage data can be transmitted daily, weekly or monthly. These usage pattern data provide valuable information for program service providers and advertisers, which can be used to better select individual subscribers and groups of subscribers with products and services with which they will be doubly interested. In addition, the usage pattern data allows interested parties (for example, promoters and advertisers) to determine the effectiveness of the various promotions. For example, when the digital coupon information provides a PPV program at half the price to subscribers who order the PPV infrequently, the success rate of the PPV P1449 / 98MX program can be determined from the usage pattern data in function 125. As another example, when information from digital coupons provides two free days of access to one of a number of enhanced services, available from programs , the improved, selected service of programs can be inspected and the subscriber can subsequently be offered a digital coupon that allows him to update the improved service, selected from programs, for example, at half the normal charge of the first month. Various other marketing strategies may be used with the present invention to improve the income and goodwill of the customer. For example, a subscriber can be given credit in coupons for a free pay-per-view movie on his birthday. In addition, the balance of the digital coupons can be adjusted according to lotteries or other contests or games. For example, subscribers may be allowed to enter a lottery for additional coupons if they spend a certain amount of money or if the subscriber can play interactive games of chance where the prices and losses are determined in terms of the coupons. However, even if the usage pattern data is not reported back to function 125, the inspection means in the terminal can determine if the data of the P1449 / 98MX use pattern satisfy the preconditions of digital coupon information. Preferably, this is done in a secure manner to prevent counterfeiting by pirates, as discussed in further detail below. The controller 130 causes the information of the digital coupons of the function 135 to be encrypted and multiplexed in the encryptor / mux / modulator 150 together with the data of program services and the function 140 and the control data of the function 145. - - The data of the program services may comprise the video and / or audio data that is stored locally in the storage medium and / or that is received from an external source such as a satellite link. Alternatively, the program service data may comprise computer programs or other electronic information. The control data includes cryptographic data that is used to generate work keys in the terminals to decode the received data. Typically, one or more enhanced program services are communicated with the basic program services on channel 120. Both basic and enhanced program services can be accessed with the possession of the appropriate group key or keys. The group key or group keys are distributed as part of a message from P1449 / 98MX authorization management (EMM). The position of the key or group keys together with the appropriate authorization control data allows the terminals to retrieve the program keys from the program data sent by the service provider by sending Authorization Control Messages (ECM). The program keys allow the derivation or decryption of the work keys used to encrypt the programming signal in the uplink or main section, and to decrypt the program signals in the downlink or section of the consumer decoder. The term "recover" is used herein to indicate that a program service is received at a terminal and is retrieved for use (eg, display) by the subscriber. The control data included in an Authorization Control Message (ECM) is used to control access to a particular program service (ie, channel). The ECM control data sends the terminal the authorization that needs to be held by the terminal in order to be authorized for access and retrieve the services of particular programs. Typically, the ECM message that distributes the control data information is also used to distribute the program key information. Therefore, the ECM message does not P1449 / 98MX defines only the parameters of the program but also distributes a key or precursor key (for example, pre-key). The ECM control data may additionally include the data to provide the terminals with the cost to order a PPV program. These control data can additionally indicate the cost, in terms of the number, the type of coupons required to access the program, along with other details that list what number of coupons is required for a discount, and so on. Figure 2 is a block diagram of a subscriber terminal according to the present invention. The elements with "similar numbering correspond to the elements of Figure 1. A demultiplexer / demodulator 205 of the terminal 170 receives the data of the program services, the information of the digital coupons and the control data of the route 122 and the connection port 124. Demultiplexing and demodulation are performed using conventional techniques.The encrypted data of the program services are provided to a decryption processor 212 and a switch 218 via lines 210 and 214, respectively, while the encrypted data of control and information of the digital coupons are provided to a P1449 / 98MX secure processor 220 via line 230. Encrypted program services are decrypted by decryption processor 212 to provide a clear signal at output 216 of the decryption processor. The secure processor 220 may receive the encrypted information from the digital coupons of the decryption processor 212. The decryption processor 212 may use a conventional decryption scheme, such as that described in Gilhousen, et al., US Patent No. 4,613,901 entitled "System of Signal Encryption and Distribution to Control the Selective Encryption and Remote Decoding of Television Signals "or Bennett et al., US Patent No. 4,864,615 entitled" Reproducing Secure Keys When Using Distributed Key Generation Data ", both incorporated herein by reference. The decryption processor requires work keys (WK) to decrypt the signals input to it via line 210. The work keys are generated by the secure processor 220 in response to the control signals received via line 230. The fixed instructions for the secure processor are stored in the read only memory (ROM) 224. The secure processor 220 is also provided with a random access memory P1449 / 98MX (RAM) 222. A secure portion of the RAM 222 maintains the unit-specific keys and / or sends for the use of the decryption of a monthly group key, as discussed in further connection with Figure 3. A user interface 226 allows a viewer to select to view program services on a television (TV) 180. If a user is authorized to receive the selected service by subscription, individual purchase (for example, payment by event), or In accordance with a digital coupon credit, the secure processor 220 will operate the switch 218 to couple the decrypted output 216 of decryption 212 to the TV 180 via the user interface 226. Otherwise, the user interface and the TV will only receive the encrypted signal via line 214 and switch 218. Corro will be appreciated by those skilled in the art, switch 218 may alternatively be configured to provide a noisy channel (e.g., a message f ijo) the user, or no signal at all, in case the user is not authorized to access the selected service. The secure processor 220 inspects the programming that is selected by the user via the user interface 226 to determine whether the user has satisfied the preconditions to obtain the credit of the digital coupons. For example, if the digital coupon P1449 / 98MX provides a credit for a free PPV program when five PPV programs are purchased at regular price, the secure processor will record each occurrence of an acquisition of a PPV program. The RAM 222 can be used to store the corresponding data. The usage pattern data thus includes the data that relates to the preconditions of the digital coupons but may include other selections as well. A communication interface 230 such as a data mode is provided to allow the terminal to transmit purchase orders for VOD programming and certain types of programming that require authorization from the service provider for the acquisition to function 115 of - PPV order processing of Figure 1. PPV acquisitions processed locally by the terminal and located internally to the terminal can be sent to the PPV processing function for billing purposes. The interface 230 also allows the terminal 170 to transmit the data of the form of use to the function 125 of accounting for the usage pattern of Figure 1. The terminal receives the control data in the form of a Management Message. Authorization (EMM) that provides an initial balance of the money credit for terminal 170. In this case, when a user orders PPV programs, for example, the total credit balance of P1449 / 98MX money is decreased by the cost of the programs. The EMM message originating from the service provider may or may not distribute an initial or additional credit of coupons to the terminal. Typically, coupon credit is generated when preconditions are made to obtain credit for digital coupons. The credit balance of the coupons can be adjusted immediately. As an illustration, it is assumed that the initial credit balance is $ 40, and each PPV program costs $ 5. Then, the credit balance will successively fall to $ 35, $ 30, $ 25, $ 20 and $ 15 after the first five programs are purchased. At this time, the data of the form of use satisfy the preconditions of the information of the digital coupons, and the balance of the coupon credits is increased by one. Alternatively, the credit balance of the coupons is increased by one in each PPV acquisition. When the terminal tunes to the sixth program, the terminal receives an Authorization Control Message (ECM) for the program. The terminal uses ECM to determine the different ways in which the program can be accessed. The ECM will also distribute the cost of money and the cost of coupons, if the program is available by coupons. The terminal will automatically determine if the P1449 / 98MX terminal has a coupon or coupons, or not, to acquire the program. If so, the program is automatically offered to the viewer, or it is suggested to the viewer to purchase the program using money or coupons. When choosing the coupon option, the next order for a PPV program is provided - free, and the coupon credit field is decreased appropriately. In this way, the balance remains at $ 15. Alternatively, the terminal is charged for the sixth program, but the secure processor increases the credit balance for the cost, so there is no absolute change in the credit balance. The secure processor may provide a display in the user interface 226 that informs the viewer that the preconditions of the digital coupon information have been satisfied. Of course, it is possible that the coupon credits accumulate when the corresponding preconditions are met, but the credits are not made, that is, they are not charged. The credits can be held in the terminal for a predetermined time. Such as two or three months, or deferred. The secure processor can inform the subscriber if the credits are close to expiration. --- r As described in further detail below in conjunction with Figures 4-6, the viewer P1449 / 98MX can ask the user interface 226 to determine the credit balance along with other related information. Figure 3 is a Jaloques diagram illustrating a decryption hierarchy for use with the present invention. An encrypted program pre-key is entered via terminal 340 to a decryption function 344 that also receives a monthly group key via terminal 342. The program pre-key is unique to each encrypted program offering (e.g. television program) that is available for decryption. The group key is changed periodically, for example, once Cell month. The decryption function 344 decrypts the encrypted program pre-key to provide a program pre-key that is used as an input to a unidirectional function 348. The other input to the unidirectional function 348 comprises various attributes of programs and coupons, including access requirements, such as cost of coupons and money, for the corresponding program. The access requirements must be met to obtain the authorization to see the program. Program attributes and coupons are entered via terminal 346, and the unidirectional function processes the program pre-key and program attributes to provide a key to P1449 / 98MX program. The output of the program key from the unidirectional function 348 is used as an input to another unidirectional function 352 which also receives, via the terminal 350, an initialization vector (IV) representative of time. The initialization vector processing and the program key by a unidirectional function 352 generates the work keys required by the decryption processor 212 of Figure 2 to decrypt the program service 'selected by an authorized user. A further description of the generation of the various keys, including the work keys (provided in a "key stream"), can be found in the Bennett et al. Patent, mentioned above. Optionally, the information of the digital coupons and the program services can be encrypted according to a common, cryptographic key. This could allow an authenticated file, for example, that represents a coupon image, which is sent to the decoders. The coupon could be subsequently reimbursed as an authentic image by transmitting the coupon from the decoder to the program service provider or other accounting center. Figure 4 is a screen display for P1449 / 98MX the user interface according to the present invention. The display 400 can be called as part of a graphical user interface (GUI) that allows a user to select channels and control other features such as volume and the like. These interfaces are well known in the art. The display 400 can be controlled by a portable remote control, or a signaling device, a voice command or other available means. For example, a user may select a PPV program such as a movie from a graphical user interface that causes the display 400 to appear. The display 400 includes a field 410 that informs the user that it is not currently subscribed to the selected program . That is, the user must order the program. Field 420 informs the user that he has different options when ordering a schedule. Fields 430-460 represent the options. A field 440 represents a first option, wherein the movie can be purchased as a pay-per-event-impulse program (IPPV) with the cost deducted from the available balance of the cash credit. The user is informed in this way of the cash cost of the film and the available balance of the credit in cash. The program can be acquired while there is a credit balance of cash P1449 / 98MX enough. A field 450 presents a second option, where the program can be acquired using only digital coupons. The user is informed of the cost of coupons for the film and the available balance of the coupon credit. The program can be purchased while there is a sufficient credit balance of coupons. Digital coupons are referred to here as "TV" coupons. A 46U field represents a third option, where the program can be acquired using a combination of cash and digital coupons. The user is informed of the cost of the film using both coupons and cash, and the available balance of the credit in cash and the credit balance of coupons. While a combination of cash / coupons is provided in field 460, it will be understood that other combinations may also be provided. Actually, the coupons can be assigned to an effective value for this purpose, In another option, not shown, a subscriber can order a PPV program for a discount if the subscriber is willing to make the commercial messages appear, that of another - mode would not be present. For example, a commercial message using teletext can appear in the button portion of the screen when you watch a PPV movie, or, with a DOV, the P1449 / 98MX PPV film chosen can have periodic business message intermediates when the discount program is selected, whereas the commercial ones would not be provided otherwise. Figure 5 is another on-screen display for a user interface according to the present invention. Here, the display 500 provides the credit number information in ^ coupons that have been accumulated while viewed in different channels. For example, the various program service providers can provide viewers with coupons based on the number of hours that service provider sees per week, and / or what programs they viewed. Fields 510 and 530 list the various program service providers, while fields 520 and 450 list the number of coupon credits that have been accumulated, for example for the service provider, Home Box Office (HBO), there is a balance of four coupons. In this way, program service providers can compete to feed the audience. For example, when a new program is launched, additional coupons can be provided. Additionally, coupons can be accumulated based on the time of day or day of the week the programs are viewed. In addition, the service providers of programs that are available P1449 / 98MX can commonly grant coupons to encourage the hearing of their programs. Figure 6 is still another on-screen display for a user interface in accordance with the present invention. The display 600 provides an example of the variety of items that the subscriber may select using the digital coupons of the present invention. In addition, each of the program service providers, along with other interested parties, can offer their own articles. A field 610 indicates that the particular display 600 is that of the service provider, Cable New Network (CNN). A field 620 indicates the current credit balance in coupons, while a field 630 indicates the items that can be obtained, field 640 indicates the number of coupons needed to obtain each item. In this way, the user p > You can reimburse digital coupons for a variety of items, including additional programs, which can be communicated to or accessed by the terminal, as as non-programming items that can be distributed to the user's home, for example, by mail. Some items may not require any digital coupon. For example, a field 650 describes the product information that can be communicated to the terminal of the P1449 / 98MX subscriber or distribute to the subscriber's home at no cost. However, when the subscriber requests product information, the usage pattern data is updated and can be subsequently provided to the use accounting function 125 of the use pattern of Figure 1, where it can be used for marketing purposes . Figure 7 is a flow chart illustrating a method for providing digital coupons in accordance with the present invention. The flowchart describes a modality where an initial credit balance is provided in cash to a terminal, for example, on a monthly basis. Then, the user wants to see the programming such as the PPV programming that has an associated cost, the cost is deducted from the credit balance in cash. Additionally, when the user satisfies the preconditions of the digital coupon information as determined by the usage pattern data, a credit balance is accumulated in coupons. The credit balance in coupons can be used to purchase the additional services of programs instead of cash, or optionally, to pay for the cost of programs already acquired. In the latter case, coupon credits can be assigned to a cash value. In block 705, the controller in the transmitter distributes an initial credit balance in cash to the P1449 / 98MX terminals. The account distributed to each terminal can be different and can be based, for example, on the previous shopping habits. In block 710, the controller distributes the information of the digital coupons to the terminals. Again, different terminals can receive different coupon data according to demographic and similar factors. In block 720, the usage pattern in the terminal is inspected and recorded. In particular, events that satisfy the preconditions of digital coupons are recorded, while other data illustrating user data are also recorded. The preconditions of the digital coupons can account for a variety of events, such as if the subscriber has acquired a given number N of PPV programs in the last M days (block 722), in which case a coupon credit is granted digital "1" - in block 724. It will be appreciated that different types and amounts of coupons can be granted according to the particular precondition that satisfies the viewer. For example, some credits on coupons may be more valuable than others, or they may be reimbursed for different benefits. In block 726, if it is. determines that the subscriber has acquired X $ of PPV programs in the last Y days, a credit "2" of coupons is granted P1449 / 98MX digital in block 728. In block 730, the subscriber has seen an "infocomercial" during a number Z minutes, a digital coupon "3" is granted in block 732. An "infocomercial" is a commercial message that has the duration and format of a regular program, for example, such as half an hour or more, and in general accumulates a relatively small audience. For marketing purposes, it is desirable to reward the viewers to see the infocomerciales even if there is no charge to see the program. Optionally, credit can be charged in coupons only for the first time the program is viewed, thus the additional credits in coupons are not granted for repeated views of the same program. In block 734, if the subscriber has been upgraded from a basic programming level to a programming level, improved, or at an improved, higher programming level, a digital coupon "4" is granted in block 736. In block 738, if a promotional period is in progress, a digital coupon "5" is granted in block 740. This promotional period would apply in general to all subscribers. In block 750, the total amount of credits in coupons is determined. In block 760, if the credit balance in coupons is above zero, then in block 770, the user is suggested by the interface of P1449 / 98 X user (for example, each time the television is tuned) select from the various options that are available in the digital coupons refund. For example, the subscriber can order the PPV programming for a discount or no charge, access the improved programming for a predetermined period of time, or simply go through and take advantage of the options available at another time. The various options have been discussed above in greater detail in conjunction with Figures 4-6. In addition to the periodic suggestions described above, a user - will also have the ability to access the refund and coupon menu at any time via the remote control. In block 780, the balance of the digital coupons is adjusted by the number of coupons reimbursed in block 770, and the inspection of the use pattern of the terminal continues in block 720. It is noted that it is possible to verify that the user is actually viewing a particular program by requiring some kind of subscriber involvement. For example, to verify that a subscriber has seen an infocommercial during Z minutes, the terminal can - require the subscriber to enter an order to the user interface. The user interface can provide a message, "want to continue" to which the subscriber must respond to P1449 / 98MX satisfy the preconditions of digital coupons. An internal timer inside the terminal can be stopped until a response is received. For subscribers who see infocomerciales and similars, to ensure that only a group of coupons are granted per program, the field CUPON_REGISTRO_DURACIÓN as discussed later in Table 3 is provided to indicate a duration in which the program record of the infocomercial is stored in the terminal. This prevents the same subscriber from obtaining repeated coupons for the same infocomercial that is running over and over again, while allowing the same program ID to be used repeatedly for the infocomercial. The data distribution syntax discussed later in Tables 1-4 may be used in accordance with the present invention. Tables 1-3, respectively, describe data fields that can be used when digital coupons are distributed to terminals using an EMM, an IPPV ECM purchase link, and a program re-key ECM. Table 4 describes the data fields that can be used with all distribution methods. It should be noted that the syntax shown is for illustration only and that other data distribution systems can be substituted.

P1449 / 98MX TABLE 1 TABLE 2 P1449 / 98MX TABLE 3 P1449 / 98MX TABLE 4 P1449 / 98MX To thwart piracy, only digital coupons can be offered to subscribers with PPV account, impulse, established where there is a capacity for return or return of report. This can be done by using a bit as an indicator in either the EMM group key or the program key re-ECM. The report return characteristic discussed above in conjunction with the data usage function 125 of the usage pattern of Figure 1 allows the service providers and the network controller to inspect the audience size for different programs. The use of digital coupons can therefore allow service providers to detect the patterns of the audience during a broad section of programs, and not just improved shows. In other words, the shows that are only available through PPV could be available through coupons. In the following program distribution scenarios, it is assumed that there must be a real channel (ie, programs) that can be purchased with coupons. This can be enforced by shredding or separating program information to generate a program key as explained further below. For the P1449 / 98MX so much, you can see a program using digital coupons unless it is actually offered to coupon holders. However, pirates may try to alter the distribution of coupons. The main objective of the pirate is to defeat the system and provide false messages (for example, "simulation") to obtain digital coupons without having to make any of the pre-conditions of coupons. In accordance with the present invention, different ways to safely describe the field CUPON_CREDITO to the terminals are discussed. - There are three ways to distribute the digital coupons, that is, using a group re-key EMM, an IPPV acquisition package, or a program re-key ECM. The group re-key message technique can handle a distribution of coupons to a general population of terminals as well as provide a method that links to IPPV acquisitions. However, the IPPV acquisition link could be made independent of the distribution of the group re-key message. The description of coupons and the group re-key message can be mutually exclusive of the program re-key technique, since, with the program re-key technique, the network controller or the processing center PPV orders do not know how many coupons a subscriber could earn using the method where P1449 / 98MX generate the coupons internally through the terminal. In this way, the handling of the coupons based on the group re-key can not be handled as safely within a terminal since the coupons based on the group re-key are followed separately from the coupons in base to the re-key program. The direct distribution of coupons through an authorization management message (EMM) of group re-key is the most honest way to control the distribution of coupons to distributors. This approach is suitable for IPPV service providers who decide to reward individual subscribers based on, for example, the previous volume --- of acquisition, the service provider knows in this way which particular subscribers are receiving the digital coupons and for therefore, it can direct a specific unitary EMM to each one of the subscribers. Additionally, the group claim EMM approach is adequate to provide subscribers with digital coupons along with a designator that allows text message commercials. These on-screen displays carry advertising and can be coated on top of the video and audio displayed. As discussed previously, these subscribers are eager to see these commercials to obtain benefits P1449 / 98MX of digital coupons such as discounts on other programs. Again, service providers know exactly which subscribers agree to have text message commercials written to them, and can therefore provide them with the corresponding digital coupons through an EMM. In addition, using the data fields CUPON_CREDITO and VH_LIMITE, individual service providers can send digital coupons to individual subscribers. Each service provider is identified by the field VÍDEO_PROVEEDOR_ID. If a pirate wanted to synthesize a group key message with a false VIDEO_PROVEID_ID and CUPON_CREDIT, thus resulting in a bad group key, the pirate might be able to create false VIDEO_PROVEID_ID, CUPON_CREDIT pairs within the terminal. One solution to the above problem is to implement the use of EMM authentication. In particular, if for example the group re-key EMM used by a transmission satellite is separated. The separation is then encrypted to create an identification. A pirate can not produce a group re-key EMM, false without knowledge of the terminal's unit keys, and the hierarchy of the keys. In this case, the false message will be rejected without processing, although another way to authenticate a P1449 / 98MX message is to use public key cryptography to identify or encrypt the entire message. This can also prevent the generation of false messages. Additionally, a pirate can use "replay" attacks using legitimately constructed messages, in this case, a legitimate message is saved and delivered to a terminal months after the message was originally created and used first to be the new CUPON_CREDIT within from the terminal. To protect against this, the numbers of the group sequences can be increased. In addition, the pirate may try to repeat the message in the same month that it was generated. To protect against this, you can follow the new CUP0N_CREDIT0 during a particular month. At the end of the month you can add to the CUPON_CREDITO that was won in previous months. When the CUP0N_CREDIT0 field is sent to the terminal during the month in the group re-key EMM, it would be the pure coupon credit issued to a particular terminal. In addition, an additional field can be created, CUP0N_CREDIT0 can be created inside the terminal to handle the coupons from a service provider for that month. Another way to ensure against repeat attacks within the same month would be to sequence the same EMMs. Then, the decoder may be able to differentiate between the P1449 / 98MX new message and one that you have seen before ,. Another method would be to include a date / time parameter in the EMM. As with a sequence number, this field can be either forward or remain the same, but can not change to a past value. For each individual service provider, any new CUPON_CREDIT value must be authenticated, for example, in the group re-key message just as with the fields CUPON_CREDITO and VH_LIMITE since only the identification of the message or using public key cryptography is not will prevent these repetition attacks. In addition, each new coupon record must follow the sequence number that indicates when it was generated. When the time of the group key occurs, the group re-key EMM that was originally used to operate the coupon register will not be able to create additional coupons since the message will be old. At that time, this new credit coupon can be added to the old CUPON_CREDITO. If, during the next month, no new coupons are sent to the terminal, and all existing coupons are used, then the entire record of the coupons can be deleted. In a second method of distribution of digital coupons, the coupons are distributed through an IPPV purchase link. With each IPPV acquisition, a bit in the program re-key message allows a P1449 / 98MX service provider distributes one or more coupons automatically and instantly to subscribers without waiting to obtain a return report or perform a "tour" (eg, distribution) with coupons as the re-key method of group discussed above. If a subscriber does not have a coupon from a particular service provider before, a new record of coupons from service providers is made. The process of creating coupons is therefore linked -firmly to the actual acquisitions of IPPV programs. After the number of coupons has been increased, they can be reimbursed to the subscriber. "Typically, a service provider will offer digital coupons that can be reimbursed only for those service provider programs, however, groups of service providers can collaborate to provide if interchangeable coupons are desired. -pirata, a pirate may try to manipulate the number of coupons that are granted when the preconditions of the digital coupons are covered, for example, such as acquiring a number of IPPV programs.A possible solution uses a separation of DES with encryption ( for example, identification) or encryption by public key of the program's re-key message.

P1449 / 98 X number of coupons in the report of. return of IPPV, then the manipulation of the pirate of this field would cause a wrong cryptographic field. If the pirate knows the group's key, falsification could occur, but it could be detected if the use history information is used (for example, usage pattern data) to separate the value of the coupon and sent together in the return of the report. In addition, if a public key cryptography was used in the distribution of the program's re-key message, then even if the pirate knew the public key of the group, a message could not be synthesized yet, since the group's private key It would not be known. Cryptography by public key has a distinct advantage over secret key cryptography since the encrypted or private key of the group is not in the terminal. As a result, the examination of the BLIS and other attacks against the terminal can not reveal the key. In a third method of distribution according to the present invention, digital coupons are distributed in conjunction with long-running commercial programs known as "infocomerciales". Preferably, a subscriber is rewarded with digital coupon credits only after viewing the program for a specific amount of time. Additionally, to prevent the subscriber P1449 / 98MX simply tune the program and leave, it might be advantageous to require some kind of subscriber involvement such as a control entry that is requested for the user interface. A pirate may be able to alter the code in an unsecured processor to automatically provide the subscriber's control signal of involvement. However, the amount of time the program should be viewed, or at least tuned in, can be assured, to do this, there is no need to track the maximum time the program lasts since the infocomercial service provider is essentially paying to the subscriber to see the program. The field PROGRAM_PAYMENT_DURATION can be loaded in a regressive timer to give force to the minimum time requirement for use of the service provider of the digital coupons. The coupons are so issued when the timer counts down to zero, and the timer counts up only when the commercial info channel is tuned. Essentially, this joins the terminal to tune the infocomercial and send it tune to another channel. Additionally, the CUPON_REGISTRO_DURACION field is required to determine when the program record of the secure processor memory should be canceled.

P1449 / 98MX A pirate may attempt to manipulate the field in the re-key ECM of the program, which indicates how many coupons are to be granted when the infocomercial is seen. One possible solution is to use a separation of DES (for example, identification) or encryption by public key of the program's re-key message. Similar to other attacks described above, the identification of the program's re-key message makes it hard for the pirate to falsify the program's re-key message without knowledge of the g's secret key or private key. Also, if public key cryptography is used in the distribution of the program's re-key message, then even if the public key of the g was known by a pirate, a message could not be synthesized since the g private key It is not known. In another possible attack of the pirate, the pirate registers legitimate messages of the program, and repeatedly reproduces the messages to the terminal. The pirate can modify the terminal to provide control inputs directly on the chip or microcircuit via the user interface to increase the number of coupons maintained with the chip. One solution to this attack is to create and store a program record in memory. In particular, the field CUPON_CREDITO is used to authenticate the number of coupons granted. In addition to CUPON_PKG_ID P1449 / 98MX and CUPON_PROVEEDOR_ID, two duration timers are needed instead of one. A timer, CUPON_PAGO_DURACION, continues for how long the subscriber must tune the program before the vouchers are granted, and the other timer, CUP0N_REGISTRO_DURACION, continues when the program record can be expired from the memory. The amount of time a record should be retained may be, for example, two months. The distribution of program re-key messages by public key is a secure mechanism. A pirate would need to cryptographically search for the g's private key to alter the program's re-key messages. The private key of the g is not distributed to any part of the terminals in the network. The duration of distributed g public keys can be extended according to the threat of piracy, perceived. And, public and private g keys can be changed thh the distribution of the new EMMs. If there is a break in the system, the infocommercial feature can be abandoned simply by making the program's re-key ECMs with the issuing feature of coupons that it issues, or that it does not allow IPPV acquisitions with the coupons. - In the previous discussion, it was found that there are three different methods to distribute coupons to terminals.

P1449 / 98MX The first is based on g re-key EMM, and the second is firmly attached to IPPV authentication, and the third is based on the program's re-key ECM using the concept of "infocomercial". The g re-key method is similar to how the IPPV is implemented with only the given pure CUPON_CREDITO, and requiring a CUPON_DEBITO field that exists within the terminal for each -service provider with a CUPON_PROVEEDOR_ID. The IPPV acquisition link method is a hybrid between the g re-key method and the program re-key method since it takes advantage of the IPPV authentication that is already done and authenticates securely within the terminal, then it is distributed by a re-key ECM program with the parameter property set. Coupons that use this method can be distributed only thh a real acquisition of IPPV. With the re-key program method, the reimbursement of coupons can be linked or not to the report on the back of the history of use history. To audit the hearing, the coupon refund is attached to the return report since a communication link such as a telephone network is required. Therefore, it can be seen that the present P1449 / 98MX invention provides a system to transmit digital coupons to subscribers' terminals for various promotional purposes. By distributing and managing vouchers electronically, vouchers are more likely to be used by subscribers and the distribution and handling costs for promoters are significantly reduced. Subscriber constancy can be rewarded, while subscribers can also be selectively selected to try the programming in which they are likely to have a special interest. Subscribers can still be encouraged to watch commercial programming such as infocomerciales. Additionally, with an optional return report feature, data on the terminal's usage pattern can be retrieved and analyzed to determine the effectiveness of the promotions and to gather additional demographic and individual data. In addition, the integrity of the scheme can be assured with various encryption techniques. Although the invention has been described in conjunction with several specific embodiments, it will be appreciated by those skilled in the art that numerous adaptations and modifications may be made thereto without departing from the spirit and scope of the invention as set forth in the claims.

P1449 / 98MX For example, coupon credit balance accounting can be maintained by the network controller or another entity separate from the terminal. This accounting can be updated in real time as the balance of the coupons changes, or periodically, such as where an automatic report return capability is provided over the phone.

P1449 / 98 X

Claims (30)

NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property:

1. A communication system comprising: a controller for transmitting program services to a plurality of subscriber terminals via a communication channel; the services of programs that are adapted to be selectively retrieved by subscriber terminals; the controller is adapted to distribute the information of the digital coupons to the terminals via the communication channel; the information of the digital coupons allows the terminals to obtain credit when they recover a first particular service of the program services according to the preconditions of the information of the digital coupons; the terminals maintain a current credit balance obtained.

2. The system according to claim 1, wherein: P1449 / 98 X credits are usable in obtaining a second particular service from the program services at a reduced charge.

The system according to claim 1 or 2, further comprising: an inspection means for inspecting a usage pattern of a terminal selected from the terminals, to determine whether the preconditions of the information of the digital coupons have been satisfied; the usage pattern that is indicative of at least one of: (a) which of at least one of the first services of particular programs has been retrieved by the selected terminal; and (b) a duration during which at least one of the first services of [particular] programs has been retrieved by the selected terminal; where the credits are provided when there is a correlation between the use pattern and the preconditions of the information of the digital coupons.

The system according to one of the preceding claims, further comprising: a user interface - to selectively reimburse the credits according to a user input. - P1449 / 98MX

5. The system according to one of the claims, further comprising: a user interface for obtaining a confirmation of the user's involvement when a corresponding terminal of the terminals is recovering the first particular services of the program services. The system according to claim 3, wherein: the first particular services of the program services provide a plurality of individual programs that are adapted to be retrieved individually by the selected terminal; and the credits are provided when the usage pattern indicates that the selected terminal has recovered at least one of: (a) a predetermined number of the plurality of individual programs; and (b) a predetermined amount of charges incurred by the selected terminal in the recovery of at least one of the individual programs. The system according to one of the preceding claims, further comprising: a means operatively associated with the controller to encrypt the information of the coupons P1449 / 98MX digital and program services according to a common cryptographic key. The system according to claim 3, further comprising: an accounting center of the usage pattern that is operatively associated with the controller; the accounting center of the use pattern that is adapted to receive the information indicative of the use pattern of the terminal selected from the inspection means via a communication link; the controller that receives the information indicative of the usage pattern of the accounting center of the use pattern to control the distribution of the information of the digital coupons to the selected terminal. The system according to one of the preceding claims, wherein: the controller is adapted to distribute different information of digital coupons to different terminals of the plurality of subscriber terminals. 10. A subscriber terminal in a communication system, comprising: means for selectively recovering the program services received from a controller via a communication channel; P1449 / 98MX a means to receive the information of the digital coupons from the controller via the communication channel; the information of the digital coupons allows the terminal to obtain credits when it recovers the first services particular of the services of programs in accordance with the preconditions of the information of the digital coupons; and a means to maintain a current balance of the credits obtained. The terminal according to claim 10, wherein: the credits are usable-in obtaining the second particular services of the program services at a reduced charge. The terminal according to claim 11 or 12, further comprising: an inspection means for inspecting a usage pattern of the terminal to determine whether the preconditions of the information of the digital coupons have been satisfied; the usage pattern that is indicative of one of: (a) which of at least one of the first services of particular programs has been recovered by the terminal, and P1449 / 98MX (b) a duration during which at least one of the particular programs has been recovered by the terminal; the credit that is provided when there is a correlation between the use pattern and the preconditions of the digital coupons information. The terminal according to claim 12, wherein: the first particular services of the program services provide a plurality of individual programs that are adapted to be retrieved individually by the terminal; and the credits are provided when the usage pattern indicates that the terminal has retrieved at least one of: (a) a predetermined number of the plurality of individual programs; (b) a predetermined amount of charges incurred by the terminal and the recovery of at least one of the individual programs. The terminal according to claim 12, further comprising: a communication interface for communicating information indicative of the usage pattern of the inspection means to an accounting center - of the usage pattern, which is operatively associated with the - - driver, via a P1449 / 98MX communication link; the controller that receives the information indicative of the use pattern of the accounting center to control the distribution of the information of the digital coupons to the terminal; The terminal according to one of claims 10 to 12, further comprising: a means sensitive to a user interface to allow the interface to selectively reimburse the credits according to a user input. The terminal according to one of claims 10 to 15, further comprising: a means responsive to a user interface for obtaining a confirmation of the user's involvement when the terminal is recovering the first particular services and the program services. The terminal according to one of claims 10 to 16, wherein: the information of the digital coupons and the program services are encrypted according to a common cryptographic key. - 18. The terminal according to one of claims 10 to 17, further comprising: an authentication means for authenticating cryptographically the information of the coupons P1449 / 98MX digital. 19. The terminal according to claim 18, wherein: the authentication means authenticates the information of the digital coupons according to a group key. The terminal according to claim 18 or 19, wherein: the authentication means authenticates the information of the digital coupons according to a public key. The terminal according to one of claims 10 to 20, wherein: the program services include programs that are encrypted according to associated program re-keys; and at least one particular re-key of the program re-keys is communicated to the terminal to allow the terminal to decrypt and retrieve the associated program using the program re-key; and the information of the digital coupons is communicated to the terminal with the program re-keys. 22. A method for transmitting digital coupon information from a controller to a plurality of subscriber terminals in a communication network via P1449 / 98MX a communication channel, the network that is also used to communicate program services from the controller to the plurality of subscriber terminals, the program services that are adapted to be selectively retrieved by the subscriber terminals, which comprise the steps of: selecting at least one terminal selected from the terminals to receive the information of the digital coupons; distribute the information- from the digital coupons to the terminals via the communication channel; the information and the digital coupons that allow the terminals to obtain credits when the first particular services of the program services are recovered according to the preconditions of the information of the digital coupons; and maintain an existing balance of the credits obtained in the terminals. The method according to claim 22, wherein: the credits are usable in obtaining the second particular services of the program services at a reduced charge. The method according to claim 22 or 23, comprising the additional step of: P1449 / 98MX inspect a usage pattern of a terminal selected from the terminals, to determine if the conditions of the information or the digital coupons have been satisfied; the usage pattern that is indicative of at least one of: (a) when at least one of the first services of particular programs has been retrieved by the selected terminal; and (b) a duration during which at least one of the first services of particular programs has recovered by the selected terminal, and providing credits when there is a correlation between the usage pattern and the preconditions of the information of the digital coupons. The method according to claim 24, wherein the first particular services of the program services provide a plurality of individual programs that are adapted to be retrieved individually by the selected terminal, the method comprising the additional step of: providing credits when the usage pattern indicates that the selected terminal has recovered at least one of: (a) a predetermined number of the plurality P1449 / 98MX of individual programs; (b) a predetermined amount of charges incurred by the selected terminal in the recovery of at least one of the individual programs. The method according to claim 24 or 25, comprising the additional steps of: receiving information indicative of the usage pattern of the selected terminal of the inspection means via a communication link; and controlling the distribution of the information of the digital coupons to the selected terminal according to the information indicative of the usage pattern. The method according to one of claims 22 to 26, comprising the additional steps of: providing a user input to the terminals; and selectively reimburse the credits according to the user's input. The method according to one of claims 22 to 27, comprising the additional step of: obtaining a confirmation of the user's involvement when a corresponding terminal of the terminals is recovering the first particular services of the program services. 29. The method according to one of the claims P1449 / 98MX from 22 to 28, which includes the additional step of: encrypting the information of the digital coupons and the services of programs according to a common cryptographic key. 30. The method according to one of claims 22 to 29, comprising the additional step of: distributing different information of the digital coupons to different terminals of the plurality of subscriber terminals. P1449 / 98MX