HK1166382A - Concept for efficiently distributing authorisation access information - Google Patents

Abstract

The invention relates to a device (100) for controlling service access authorisation for a user device in relation to an access restricted service. Said device comprises a service authorisation access provider (101) that is designed to control, corresponding to an authorisation message (103) provided with a service-dependent user identification (102), a period of time during which the service authorisation access (104) is present exists and to deactivate (105) authorisation that allows the service authorisation access (104) to be extended or reactivated using the previous service-dependent user identification (102), if at least one predetermined duration (123) has elapsed since the end of the last authorised time interval (106) for which one service authorisation access (104) was determined by the device (100).

Description

Scheme for efficiently distributing access authorization information

Technical Field

The present invention relates to a scheme for efficiently distributing access authorization information for a digital rights management system or an access authorization system. The invention also relates to a device and a method for controlling service access authorization, a device and a method for providing authorization information and a system for controlling service access authorization.

Background

Digital rights management systems, also known as DRM systems, are methods for checking the use and distribution of digital media. Digital usage management is used in the field of digital cinema and sound recording, but also in software, electronic documents or electronic books. Digital rights management can allow its providers to check the usage of their data, with new payment means, such as by licensing and authorizing payment for the right to use the data, rather than payment for the data itself.

Authors and users often wish to check or restrict the spread and use of their intellectual property rights, even after the intellectual property rights are passed to others. Digital rights management systems can be used to support the use of data only within the limits of the individual rights-holders (i.e., licensees).

However, digital rights management systems also exist in many other fields, such as for companies to protect their files, which may also be referred to as company rights management systems.

A digital rights management system is a technical security means that can give the owner of the right to an information commodity a way to technically enable the user to use the owner's right based on a previously established usage protocol.

In addition, the digital rights management system is also able to manage digital content in a manner that is not just a pure flat-rate, but is also able to make individual licenses or charges based on frequency, time, and scope of use. On the one hand, it will limit the use without constraints, and on the other hand, some business models that are currently difficult to implement may be implemented on demand.

An example of a digital rights management system is the Open Mobile Alliance (Open Mobile Alliance) system (known as OMA DRM), which includes OMA DRM V version 1.0 (http:// www.openmobilealliance.org/Technical/release _ program/dry _ V1_0.aspx), OMA DRM V version 2.0 (http:// www.openmobilealliance.org/Technical/release _ program/dry _ V2_0.aspx) and OMA DRM V version 2.1 (http:// www.openmobilealliance.org/Technical/release _ program/dry _ V2_1.aspx), another example of a digital rights management system is the ETSI Standard EN50094 (known as EUROCRYPT) with the version BS 50094: 1993 or Eurocrypt BE EN 50094: 1993(http:// www.beuth.de/langzeige/BS + EN +50094/9799264. html). In addition, there are also many proprietary (proprietary) digital rights management systems, which are partly defined on open platforms.

The article "digital rights management" published in Wikipedia, encyclopedia, 2008, 23, 4 summarizes the digital rights management system and briefly introduces the "Faireplay" system of "Apple (Apple)" company under the terms of the program "ituestore" and the "Windows Media DRM" system of "Microsoft (Microsoft)" company.

The most popular digital rights management systems are apple's "Fairelay", "Microsoft (Microsoft)" corporation "Windows Media DRM" and OMA DRM, the open Mobile alliance standard. These systems are able to accurately set the authorization and for different audio and video files. For example, apple, a leader of this market, uses "Faireplay" for a program called "ITunes Store". Other providers of digital content are for example Napster or Musicload. The video providing service mainly employs a DRM system provided by microsoft corporation. The OMA DRM system is used for ring tones, images, and Mobile music and television transmission in almost every handset through the content providers Vodafone or T-Mobile. OMA DRM and Windows Media DRM are often used in combination to allow interoperability between cell phones and computers. The content providers Vodafone and T-Mobile mentioned here are for exemplary purposes only.

Digital rights management systems will play a more important role in the future in many fields, for example in the automotive field for protecting real-time or online navigation software, or in the field of embedded systems.

Digital rights management systems mainly use cryptographic methods to control access to digital content. This allows, for example, any digital content to be bound unambiguously to a license by encryption. Without a valid license belonging to the digital content, the user can purchase the device or the data carrier, but cannot access the content. The content management computer may, for example, manage the protected digital content and encrypt it for use in the digital rights management system so that the content is initially unreadable. The license management computer can generate a required license in association with each key for user authentication and content decryption based on the request. When a user wishes to access protected content, he can request the re-generation of the required license from the license management computer through the digital rights management controller. After the authenticity and integrity of the reproduction of the regenerated program has been successfully verified, the content can be decrypted, for example using a key contained in the license, so that readability can be restored and the content passed to the regenerated program.

Access authorization systems or access encryption systems (also known as Conditional Access (CA) systems) generally include systems employed in pay-tv or pay-video acquisition programs for encrypting and decrypting program content, which may also be used in other digital broadcast/radio systems and for vehicle assistance.

In order for the receiver to be able to decrypt the content, it requires, for example, a constantly changing control word. Having the receiver obtain this control word and therefore only addressing (address) a particular receiver is one of the tasks to access the authorization system.

For example, the provider may transmit a separate data packet as management information, also referred to as Entitlement Control Message (ECM), at the same time as the useful data. By means of these ECMs, a receiver with a corresponding authorization can calculate the control word valid at that time and transmit it to the content decoder. The content decoder is then able to decrypt the received content. On the receiver side, the access authorization system is mapped, for example, by an authorization card bound to the customer in the form of a smart card and a customer anonymous access authorization module. The module may filter these packets including the management information from the data stream and calculate the corresponding control words from the information given in connection with the authorization card. The logic of the access authorization system can be assigned to the module on the one hand and to the authorization card on the other hand. It is a common method to store customer-specific data on an authorization card and make it unreadable by third parties.

In addition to the information already present on the client authorization card, these methods also transmit management information, including management commands, via the input data stream. These management messages (also called entitlement management messages EMM) are used to specifically enable or disable the client card. This is a way of providing the customer with the right to make more or less of the respective package (offer package) without the customer needing to change the authorization card.

Examples of digital access authorization systems are the "Betacrypt" and "Betacrypt II" systems for digital pay-tv (which are developed as software called D-Box), the "Videoguard" system for pay-tv, broadband tv and mobile applications, and the "nagravion Aladin" system which provides access control methods for satellite and cable tv.

The digital pay video systems "video" and "nagravion Aladin" are mentioned in the article "conditional access" published in the web encyclopedia Wikipedia on 12.3.2008 and are briefly introduced in the related articles "nagravion" and "video" on 28.2008 and 20.4.2008. The article "conditional access system" published in Wikipedia 2007 at 12/21 mentions Betacrypt as another access authorization system, which has been replaced by the Betacrypt II system.

Since in a one-way broadcast system the receiver is usually not able to acknowledge the received information and cannot be switched on all the time, e.g. the entire information will have to be transmitted over and over to ensure a high reception quality. To guarantee a high security standard, the access authorization information may be securely encrypted, so that decryption without a valid access key would be either economically unfeasible or technically impossible. In addition, different individual access authorization systems may be independent of each other so as not to interfere with each other.

Digital rights management systems and access authorization systems allow service providers to distribute protected multimedia content to users in a closed group. The allocation can be made using different systems, for example by means of an analog or digital video or audio broadcasting system, by means of a mobile radio communication system, by means of an internet protocol system, or by means of a digital multimedia transmission system. DVB (digital video broadcasting) system, GSM (global system for mobile communications), IP (internet protocol) system, and DAB/DMB (digital audio/multimedia broadcasting) system, and other systems are commonly used.

The content may be encrypted prior to distribution of the content. Usage rules and keys may be distributed in the further management information. The content may be grouped according to service. For example, a user of a service is a group of people that can be managed on the transmitter side.

A user may access a service when the user has stored the required authorization in his device or in a secure component connected to the device, e.g. in an authorization card (chip card). The user may obtain authorization during the personalization process.

A common business model between service providers and service users is to use subscriptions (subscriptions) to manage access. The service authorization is valid for a certain period of time, and upon expiration, may be postponed if there is a persistent business relationship between the service provider and the service user. Said postponement (Vn) is for example realized by means of management information related to a certain service. The management information may include some of which a deferral period (start) is encoded_n，end_n) Such as an available deferral start time (start)_n) And a postponed end time (end)_n) And (5) encoding.

When a digital rights management system or an access authorization system is employed in an environment where multiple receivers are capable of receiving transmitted signals ("point-to-multipoint"), such as a digital broadcast system, the deferred information may be directed to multiple service users at the same time. This means that the postponement information needs to include an address area with a list of service subscribers that need to be postponed. For these users, the deferral time (e.g., 12 months and 31 days) and the deferral period (e.g., 3 months) may be the same.

When the subscription is not deferred, no deferred information is transmitted to the corresponding service user. The authorization of this user expires.

The end of the access grant typically coincides with the time at which the subscription expires.

A subscriber management system managing a plurality of subscriber (subscriber) data of a service user of a digital rights management system or an access authorization system typically requires personalized management for managing the subscriber data, wherein a service-dependent user identifier "i" is assigned to a user device having a device identifier "g" for a specific service having a service identifier "d", wherein the service-dependent user identifier may depend on the device identifier and the service identifier. This can be formulated as i ═ f (g, d), where "f ()" refers to the correlation function. Other associations may also be employed in the personalization.

The device identifier, the service identifier and the user identifier may be stored at a transmitting side in the subscriber management system.

The peripheral device knows, for example, the personalized device identifier assigned to it for the additional service. After personalizing a plurality of (e.g. n) services, the device may permanently (or temporarily) store a service-dependent user identifier list, wherein the list may be a number sequence (d) of n pairs of service identifiers and user identifiers with coefficients 1 to n₁，i₁)，…，(d_n，i_n)。

The service dependent user identifier is for example temporary for a period of time with a corresponding service authorization.

Disclosure of Invention

The invention aims to provide a scheme capable of efficiently distributing service access authorization information.

The above object is achieved by an apparatus for controlling service access authorization according to claim 1 or a method for controlling service access authorization according to claim 29, an apparatus for providing authorization information according to claim 9 or a method for providing authorization information (or referred to as authorization message) according to claim 30, or a system for controlling service access authorization according to claim 8.

Some embodiments of the invention are based on an apparatus for controlling service access authorization for a user equipment for an access limited service, wherein a time period during which access service authorization is valid is set in response to authorization information provided with a service dependent user identifier, wherein the setting may depend on a predetermined period of time that has elapsed since an end time of a last authorization period.

Some embodiments of the invention are additionally based on an apparatus for providing authorization information for a user equipment for an access restricted service, wherein the apparatus leaves a service dependent user identifier unused for at least a predetermined period after expiry of an authorization period for the user equipment with which the service dependent user identifier was last associated.

Some embodiments are based on the finding that the re-released user identifiers are re-allocated in a controlled manner, thereby limiting the required address space (i.e. the number i of potential service dependent user identifiers) and optimizing the grouping information for efficient user addressing in the long term when applicable. When the service dependent user identifier is represented by a sequence of bits, for example, the address space limitation may result in a smaller number of bits that must be transmitted for providing service access authorization, for example. If fewer bits are needed for transmitting the service dependent user identifier, also called service related user identifier, the information containing the service access authorization, otherwise called message, can be transmitted over a channel with a smaller bandwidth and the subscriber management system only needs to keep a smaller number of data sets for managing the service dependent user identifier.

The solution of the invention makes it possible to prevent, after the reassignment of the released user identifier, the user whose user identifier has been invalidated and is called the "original user" from accessing the content again using his device. In addition, the solution of the invention can prevent users who have deferred their subscription but whose peripherals have not received deferred information from being immediately excluded from further service usage. In other words, the inventive solution enables user satisfaction, which is also commonly referred to as "good user experience".

It is to be noted that the device cannot receive the postponed information when the device remains off for a long time or in a location where the reception quality is poor (for example, when the vehicle is parked in an underground parking lot or driven out of a vehicle for vacation in the case where the device is mounted on the vehicle).

A limitation of the ease of operation is predictable for a user who has postponed his subscription, but the device has no reception conditions for a long time and is therefore unable to receive postponed information. For these users, the device may be excluded from service usage. Such a user may then contact his service provider to obtain a new user identifier or to restore the disabling parameters and keys of the respective service in his device for the old user identifier for which he is still registered in the subscriber management system.

Drawings

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

FIG. 1a is a block circuit diagram of an apparatus for controlling service access authorization according to an embodiment of the present invention;

FIG. 1b is a block circuit diagram of an apparatus for controlling service access authorization according to another embodiment of the present invention;

FIG. 2a is a block circuit diagram of an apparatus for providing authorization information according to an embodiment of the present invention;

FIG. 2b is a circuit block diagram of an apparatus for providing authorization information according to another embodiment of the present invention

FIG. 3 is a flow diagram of a method for controlling service access authorization according to an embodiment of the invention;

FIG. 4 is a flow diagram of a method for providing authorization information according to an embodiment of the invention;

FIG. 5 is an example of a timing sequence for service deferral by deferral information;

FIG. 6a is an example showing a timing sequence of service deferrals, wherein not all deferral information belonging to a subscription is received;

FIG. 6b is another example showing a timing sequence of service deferrals, where there is a period of time between the first deferral information and the second deferral information during which no deferral information is received;

FIG. 7a is an example showing the timing of a service postponement, including postponement information, device restart time, and duration;

FIG. 7b shows an example of a timing sequence of a service deferral, the service deferral comprising first deferral information, second deferral information, and a duration;

fig. 8 is a block diagram of a system for controlling service access authorization in accordance with an embodiment of the present invention.

Detailed Description

Fig. 1a is a block circuit diagram of an apparatus 100 for controlling service access authorization for a user equipment for an access limited service according to an embodiment of the present invention. The apparatus 100 comprises a service access authorization provider 101, the service access authorization provider 101 being configured for determining a time period for which a service access authorization 104 is valid, the determination being responsive to an authorization information (or referred to as authorization message) 103 provided with a service dependent user identifier (or referred to as service related user identifier) 102. The service access authorization provider 101 is configured for disabling 105 the authorization allowing the service access authorization 104 to be postponed or resumed using the previous service dependent user identifier 102 when at least the predetermined period has elapsed since the apparatus 100 determined that the end time of the last authorization period 106 of the service access authorization 104. Another embodiment for disabling 105 the authorization allowing to postpone or restore the service access authorization 104 is shown in fig. 1 b.

Fig. 1b is a block circuit diagram of an apparatus 100 for controlling service access authorization for a user equipment for an access limited service according to another embodiment of the present invention. The apparatus 100 comprises a service access authorization provider 101, the service access authorization provider 101 receiving authorization information 103, the authorization information 103 comprising a service dependent user identifier 102 and an authorization period (or referred to as period) 106 or information describing the authorization period 106. The following 5 steps, represented by functional blocks 111, 112, 113, 114 and 115 respectively, are performed in the service access authorization provider 101 according to the authorization information 103.

In a first step 111, the service access authorization provider 101 receives authorization information comprising an authorization period 106.

In a second step 112, the service access authorisation provider 101 compares the received authorisation period 106 with the last authorisation period 107 existing in the device 100. A period 120 that has elapsed since the end time 121 of the last grant period 107 and the start time 122 of the grant period 106 is determined.

In a third step 113, the service access authorization provider 101 compares the elapsed period 120 with a predetermined period 123. If the elapsed period 120 is greater than or equal to the predetermined period 123, the service access authorization provider 101 will perform step 4a 114; if, however, the elapsed period 120 is less than the predetermined period 123, the service access authorization provider 101 will perform step 4b 115.

In step 4a 114, the deferred or restored authorization to use the previous service dependent user identifier 102 is disabled 105. In step 4b 115, the service access authorization 104 is deferred or restored and the authorization for deferral or restoration using the previous service dependent user identifier 102 is maintained.

The decision parameter determining the behavior of the apparatus 100 is a predetermined period 123, which is also referred to as "keep alive period (keep alive) or KAP. With this parameter, the device 100 controls whether to disable 105 or maintain authorization for deferral or recovery using the previous service dependent user identifier 102.

The apparatus 100 for controlling service access authorization may be employed on many different devices, such as devices for audio, video or multimedia services on pay-tv systems or pay-video systems or driving assistance systems, wherein the systems may be implemented on mobile or fixed-installed devices. In addition, the device 100 may be used for data services or multimedia services on a mobile phone, or for charging services and/or access controlled services on a portable or stationary computer with or without internet access functionality.

The determination of the elapsed period 120 may be in response to the time the device was powered on instead of the start time 122 of the authorization period 106. In this case, the elapsed period 120 is the period between the end time of the last authorization period 107 and the power-on time of the device 100. That is, for example, when the device 100 has been powered off since the end time 121 of the last authorization period 107 and is powered on only at a later time. It may happen that the device does not receive the deferred information transmitted by the service provider and at the same time the period 120 that has elapsed (since the last deferred information received) determines whether the user retains its service access authorization 104 and/or the authorization for deferred service access authorization using the previous service dependent user identifier 102.

The service access authorization provider 101, for example, receives authorization information 103 including enabling or deferral information and determines from the authorization information 103 an authorization period 106 having an authorization start time 122 and an authorization end time 124. The service access authorization provider 101 enables the service access authorization 104 when the authorization end time 124 is temporally after the current time measured by the device 100, i.e., when the service access authorization 104 is valid at the current time.

In another embodiment, the authorization information 103 comprises, in addition to the service dependent user identifier 102 and the authorization period 106, a device identifier, wherein the service access authorization provider 101 first checks and compares the device identifier received in the authorization information 103 with the device identifier of the peripheral on which the apparatus 100 is implemented before providing the authorization period 106, and if there is a match, reads the authorization period 106 from the authorization information 103.

The service access authorization provider 101 is configured to maintain an authorization allowing the service access authorization 104 to be postponed or restored using the previous service dependent user identifier 102. This is shown in step 4b 115. This means that after receiving the authorization information 104 and postponing and/or restoring the service access authorization 104, the period for postponing or restoring the authorization using the previous service dependent user identifier 102 is postponed from the end time of the period in which the service access authorization is valid by the predetermined period 123. The predetermined period 123 is also referred to as a lifetime or KAP. The predetermined period of time 123 is a characteristic parameter of the apparatus 100.

The service access authorization provider 101 is additionally configured to disable the service access authorization 104 after expiration of the authorization end time 121 when the device 100 does not establish authorization of the service access authorization 104 before the authorization end time 121 or at the authorization end time 121. This means that at the end time 121 of the last authorization period 107 the service access authorization 104 is disabled, even if the authorization for postponing or restoring the service access authorization using the previous service dependent user identifier 102 is maintained. Authorization for postponement or recovery using the previous service dependent user identifier 102 is maintained for another period corresponding to the predetermined period 123. Disabling 105 the authorization for postponement or recovery using the previous service dependent user identifier 102 may be achieved, for example, by erasing, disabling or preventing parameters or keys associated with the service access authorization 104 using the previous service dependent user identifier 102.

The apparatus 100 comprising the service access authorization provider 101 may for example be implemented as an electronic circuit. It may be a computer or part of a computer, or a circuit in a mobile phone, a fixed or portable computer, a navigation system, a driving assistance system or a satellite receiver.

Fig. 2a shows a block circuit diagram of an apparatus 200 for providing authorization information for a user equipment for an access limited service according to an embodiment of the invention. The apparatus 200 includes an identifier manager 201 and an authorization information generator 202. The authorization information generator 202 is configured to generate the authorization information 103, the authorization information 103 may be in the form of enabling information (or referred to as an enabling message) for enabling the service access authorization 104 or in the form of postponing information (or referred to as a postponing message) for postponing the service access authorization 104, and the enabling information 103 or the postponing information 103 is provided with the service dependent user identifier 102 provided by the identifier manager 201. After expiry of the authorization period 106, in which the service dependent user identifier 102 is last associated with the device, the identifier manager 201 is configured to leave the service dependent user identifier 102 unused for at least a predetermined period 123, and to release 204 said service dependent user identifier 102 to be reused by the authorization information generator 202 after expiry of the predetermined period 123.

The identifier manager 201 for example comprises three boxes with service dependent identifiers: the first box 205 comprises the relevant service dependent user identifier 102, wherein it is in the authorization period 106 of the user equipment; a second block 206 comprises the unused 203 service dependent user identifier 102, wherein the authorization period 106 of the user equipment has expired less than the predetermined period 123; and a third block 207 comprises the service dependent user identifier being released 204 for reuse.

The controller 208 in the identifier manager 201 controls which service dependent user identifier 102 the authorization information generator 202 is able to use. The controller 208 here controls the provision of the associated service dependent user identifier 102 of block 205 or the unused service dependent user identifier 102 of block 206 203 or the provision of the released 204 service dependent user identifier 102 of block 207 for reuse.

The authorization information generator 202 comprises a block 210 for generating enablement or deferral information comprising the service dependent user identifier 102 provided by the identifier manager 201. Thus, the apparatus 200 provides the authorization information 103 comprising the service dependent user identifier 102.

Fig. 2b shows a block circuit diagram of an apparatus 200 for providing authorization information for a user equipment for an access-restricted service according to another embodiment of the present invention. The authorization information generator 202 has the same settings as the authorization information manager 202 shown in fig. 2 a. The function of the controller 208 shown in fig. 2a will be explained in detail with reference to blocks 220, 221, 222 and 223 in fig. 2 b. The purpose of the identifier manager 201 is to provide a service dependent user identifier 102, which is illustrated by block 220. This may be done outside the identifier manager 201 or outside the apparatus 200.

The providing includes several functionalities. In block 221, it is checked for the service dependent user identifier 102 associated with the peripheral up to that time whether the authorization period 106, 107 to which the service dependent user identifier 102 relates has expired. If the authorization period 106, 107 (during which the previous user peripheral has access to the service) has not expired, the authorization period 106, 107 associated with the peripheral until then may be used to generate enable or defer information 103 for the previous user and/or the previous peripheral. However, if the authorization period 106, 107 has expired, the service dependent user identifier 102 will remain out of service for a predetermined period 123, as shown by block 222. The service dependent user identifier 102 may be used to update the authorization period of the previous peripheral before the expiration of the predetermined period 123 from the end time 121 of the authorization period 107.

In block 223, it is finally checked whether the predetermined period 123 has expired. If the predetermined period 123 has expired, the service dependent user identifier 120 may be used again, wherein the new user may then obtain authorization information 103 comprising the service dependent user identifier 102 previously associated with a different user. If the predetermined period 123 has not expired, the service dependent subscriber identifier 102 cannot be released to a different subscriber and/or a different peripheral. The identifier manager 102 then provides the other peripheral with another service dependent user identifier 102, the availability of which service dependent user identifier 102 can be checked, for example, in blocks 221, 222 and 223 and provided to the authorization information generator 202 when available, so that the authorization information generator can generate the authorization information 103 comprising the other service dependent user identifier 102.

The authorization information generator 202 may be configured to generate the authorization information 103, the authorization information 103 enabling or postponing for example audio, video or multimedia services on a pay-per-view video system or a driving assistance system on a mobile phone or a stationary device, or data services or multimedia services on a mobile phone, or access controlled and/or fee-based services on a portable or stationary computer with or without internet access functionality.

The authorization information generator 202 may further be configured to generate the authorization information 103 comprising the service dependent user identifier 102, wherein the service dependent user identifier 102 may be represented by a sequence of bits. The authorization information generator 202 may for example be configured to transmit the authorization information 103 comprising the service dependent user identifier 102 over a limited bandwidth information channel, otherwise referred to as a message channel. In addition, the authorization information generator 202 and the identifier manager 201 may be implemented as electronic circuits.

An efficient controller 208 results in an efficient distribution of service access authorization information. This is done by re-releasing the service dependent user identifier 102 for use by another user and/or another user peripheral after the predetermined period 123, while the service dependent user identifier 102 is still unused during the predetermined period 123. This reduces the number of service dependent user identifiers 102 required for identifying the service d on the device g. As the number of service dependent user identifiers 102 decreases, the authorization information 103 including the service dependent user identifiers 102 may be transmitted using a reduced bandwidth. In addition, only a small storage space is required to store user data on the subscriber management system.

The identifier manager 201 is further configured to release the service dependent user identifier 102 after the predetermined period 123 has expired so that other users or other peripherals can be reused. After the expiration of the subscription of the previous user of the user device with which the service dependent user identifier 102 was last associated, the service dependent user identifier 102 may be reused for a new subscription of another user or of the same user after the expiration of the predetermined period 123. The predetermined period 123 may for example comprise a value in the range of 3 days to 3 months, i.e. the predetermined period may be adjusted to an authorized period, as it typically occurs for subscription services in the field of pay tv or mobile phones, navigation systems, driving assistance systems or pay internet services, etc. The authorization information 103 may be directed to multiple receivers, for example. The transmission may be used, for example, on a system known as a "broadcast system". However, the authorization information 103 may also be provided to a group of users or transmitted to only a single user.

The enabling or postponing information 103 may also take a personalized form, i.e. the service dependent user identifier 102 depends on a device identifier or a service identifier of the device on which the service is running. In addition, the enabling or deferral information 103 may be grouped in such a way that the information (or called messages) 103 of the users to the same authorization period 106 are grouped together. This allows a clear representation of a subscriber management system where subscribers who have to be deferred at the same time receive deferred information at the same time, where only deferred information 103 needs to be sent to those users who need to be deferred. Using grouping, it is possible to keep managing the deferral information 103 in the subscriber management system at a clear level and to avoid unnecessary deferral information 103.

The authorization period 106 may be specified by a start time 122 and an end time 123 or by a start time 122 and a duration. However, other approaches may be used.

Fig. 3 is a flow chart of a method of controlling service access authorization for an access limited service. Method 300 includes steps 301, 302, 303, 304, 305, and 306.

In a first step 301, authorization information 103 comprising a service dependent user identifier 102 is received. A second step 302 follows, in which the authorization start time 122 and the authorization end time 124 can be read from the authorization information 103. A third step 303 follows, wherein the grant start time 122 is compared with the grant end time 121 of the last grant period 107 with the service access grant 104. In a following fourth step 304 it is checked whether the predetermined period 123 has elapsed between the authorization start time 122 and the authorization end time 121 of the last authorization period 107 or between the authorization end time 121 and the current time. If the predetermined period 123 has elapsed, a fifth step 305 is performed in which the authorization for postponement or resumption of use of the previous service dependent user identifier 102 is disabled 105. If the predetermined period 123 has not elapsed, a sixth step 306 is performed in which the authorization for postponement or resumption of use of the previous service dependent user identifier 102 can be maintained and the service access authorization 104 can be postponed or resumed.

Fig. 4 is a flow diagram of a method 400 of providing authorization information for access limited service control. After the method 400 starts 401, in a first step 402, the potential service dependent user identifier 102 is provided, wherein it is subsequently checked whether the potential service dependent user identifier 102 is to be actually used. In a second step 403 it is checked whether the authorization period 106, 107 of the peripheral associated with the service dependent user identifier 102 has expired. If it has expired, in a third step 404 it is commanded or determined not to use the service dependent user identifier 102 for the predetermined period 123 and/or not to use it for another peripheral of the peripherals associated so far with the service dependent user identifier 102. In a fourth step 405 it is checked whether the predetermined period 123 has expired. If the predetermined period has not expired the method 400 jumps back to the first step 402, in which the service related identifier 102 is provided, this time with a different service related identifier than in the previous check. If the predetermined period 123 has expired in the fourth step 405, in a fifth step 406 enabling or postponing information 103 comprising the service dependent user identifier 102 is generated and provided.

In a second step 402, the same fifth step 406 may be performed if the authorization period 106, 107 of the peripheral with which the service dependent user identifier 102 is associated has not yet expired. For this case, the enabling or postponing information 103 comprising the service dependent user identifier 102 may also be generated in a fifth step 406. The difference between the transition from the second step 403 to the fifth step 406 and the transition from the fourth step 405 to the fifth step 406 is that in the first case the enabling or postponing information 103 comprising the service dependent user identifier 102 is provided to the previous user, and in the second case the enabling or postponing information 103 comprising the service dependent user identifier 102 is provided to the new user, but the new user may also comprise the previous user.

FIG. 5 shows an embodiment in accordance with the inventionTiming diagram for service deferral by deferral information V_k 500、V_l 501、V_m502 and V_n503 to show the service postponement process. The end time of access grant 504 is defined by time end_n517, respectively. The service for which access authorization is available may be deferred using deferral information. In this embodiment, service subscriber receives deferral information V at time 505_k500, in which the postponement information V_k500 includes two parameters, start, for an access grant period_k510 and end_k511, indicating the time period included by the extension of the service access authorization. For example, if a service user has initiated or applied for its service access authorization to be postponed to time end (e.g., by paying a fee)_k511, it may be at time end_k511 receives the postponed message V in a period immediately before_l501, the postponement information V_l501 can defer the access authorization of the service user by a deferral message V_l501 by parameter start_l512 and end_l513, respectively. The service provider may repeatedly transmit the deferral information V shortly before the end of each subscription_l501 to allow service users to defer their service access authorization. Since the service user may not always have his device switched on or may be in a location with poor reception quality, the postponed information V may be sent several times in sequence shortly before the end of each subscription_l 501。

For example, if a service user defers its access authorization to time end_l513 and also postpones their subscription, the service provider may at time end_l513 shortly after the end of the transmission of the postponed information V to the service user_m502, service user uses the postponement information V_m502 may grant its service access from a time start_m514 extending to time end_m515. The service provider may be at time end when the subscription continues to be active_m515 transmitting additional postponement information V shortly before the end_n503 so that the service user can defer his service access authorization for a time period start_n516 to end_n517. For example, when subscribing to the time end as shown in FIG. 5_n517, where time end_n517 coincides with the end time of the access grant 504, the service provider will not transmit further deferral information to the service user and the service user's service access grant expires. In fig. 5, the respective service access authorization periods 520, 521, 522 and 523 are consecutive in time. However, this need not always be the case. For example, there may be a small period between time period 521 and time period 520 during which the service user does not have service access authorization, e.g., the user does not defer his subscription on time, and the deferral information 501 is only at time end of the first authorization period 520_k501, and then transmitted. However, fig. 5 also shows that the service user's service access authorization depends on the message transmitted to it by the service provider, and that the service user relies on deferral information 500, 501, 502 and 503 received from the service provider in order to defer his service access authorization. Without this deferral information, it would be impossible for a service user to maintain their service access authorization.

Fig. 6a is a timing diagram of service deferral according to a similar embodiment of the present invention, wherein not all deferral information belonging to a subscription is received. Unlike fig. 5, the postponement information V_l501 and V_l502 are not received. The consequence is that during the grant period 521 (i.e., from start)_l512 to end_l513) And a grant period 521 (i.e., from start)_m514 to end_m515) There is no service access authorization for the user. The predetermined period 123 is shown in fig. 6a and referred to as KAP600 or survival period, the predetermined period 123 corresponding to KAP 600.

Fig. 6a shows the case where the grant start times 122 and 516 are temporally prior to the last grant periods 107 and 520, respectively, being postponed by the predetermined periods 123 and 600, respectively. Thus, authorization to defer or resume service access authorization including a previous service dependent user identifier 102 may be maintained, and the service access authorization 104 may be at a time start_n516 are deferred or resumed. This can be seen in fig. 6a, where postponement information V is indicated_k500 authorization periodTime end of authorized end time of 520_k511 is postponed for a predetermined period KAP600, with the result that postponed information V is generated_nGrant start time start of grant period 523 of 503_nTime after 516. The service user may retain its previous service dependent user identifier 102 and defer or restore its service access authorization.

Fig. 6b shows a timing diagram of service postponement compared to fig. 6 a. In FIG. 6a the postponement information V_l501 and V_m502 are shown as not received and the two deferral messages are not shown in figure 6b, i.e. at V_k500 and V_n503 have not received a number of deferred messages in time. In fig. 6b, it is indicated that the lifetime or KAP corresponds to the predetermined period 123. This lifetime KAP is known to both the subscriber management system and the peripheral. The lifetime period may be notified by communication when enabled, or may be a fixed value or determined by known parameters.

When a user subscription has expired, the end of the survival period is waited for before the corresponding user identifier can be reused by the subscriber management system for a new subscription (e.g. for a different user or peripheral than the previous one).

When restarting the device (as detailed in FIG. 7 a) or when receiving a start time "start" based on an authorization_n"and authorization end time" end_n"deferral information Vn 503 for a certain authorization period 523, the peripheral may check whether the lifetime period, i.e. KAP, has expired. The survival period, KAP600, may be added to the end time end of the last stored authorization period 520_k511 (c).

If end_k511 and KAP600 are temporally at the restart of the device (or the restart time of the device) and/or postpone information V_nThe authorization start time start of the current authorization period 523 of 503_nThereafter, the KAP600 does not expire during the survival period. Delay information V in between_l 501 and V_m502 may not be received for one of the reasons discussed above. The peripheral can carry out delay. The subscriber management system has not yet reassigned the user identifier. The deferral information points to the previous user.

FIG. 6b shows an example of postponement information V_k500 and V_n503 is received; at time start_n516, survival period KAP600 not expired, i.e. formula (end)_k+KAP＜start_n) And (4) showing. Access authorization may be deferred.

It is possible to prevent users who have deferred their subscription but whose peripherals have failed to receive deferred information from being immediately excluded from further service usage, i.e. user satisfaction is guaranteed, which is often referred to as a good user experience.

FIG. 7a is an example showing the timing of a service postponement comprising postponement information V_k500. A device restart time T700 and a survival period KAP600, the survival period KAP600 will postpone the information V_kAuthorization end time end of authorization period 520 of 500_k511 are set within the range of the device restart time T700. As can be seen from this embodiment, the authorization end time end at the authorization period 520_kAfter 511 to the device restart time T700 a longer period has elapsed than the period provided by the survival period KAP 600. Here, the device restart time T700 represents the time when the apparatus 100 starts. Because by time T700 a period has elapsed longer than the period provided by the lifetime period KAP600, the peripheral must disable 105 its authorization to include the postponement or resumption of the previous service dependent user identifier 102. It will be appreciated that the service access authorization 104, including the previous service dependent user identifier 102, has been assigned to other users.

As shown in fig. 7a, if the authorization end time end of the last authorization period 520 is received_k511 and the time of the keep alive period KAP600 is generated in time before the time when the apparatus 100 is turned on or the device restart time T700, the keep alive period KAP600 has expired. The peripheral should disable its stored parameters and keys related to this service in a secure way. The user identifier has been allocated to another use by the subscriber management systemAnd (4) a user.

In the example according to fig. 7a, the received deferred information end is illustrated_k500, a step of; at the device reboot time T700, the KAP600 has expired during the survival period, which can be expressed by the following equation (end)_k+ KAP < T). The service parameters are disabled.

FIG. 7b shows an example of a timing sequence of service deferrals, comprising two deferral information V_k500 and V_n503 and its relationship to KAP600 during survival. In FIG. 7b, when the respective grant start times start are included_n516 postponement information V_n503 arrive, from the postponed information V_kEnd time end of the last authorization period 520 of 500_kThe initial survival period KAP600 has expired. In this case, the peripheral must also disable 105 its authorization to include the postponement or restoration of the previous service dependent user identifier 102.

When the information V is postponed, as shown in FIG. 7b_n503, if the authorization end time end of the last authorization period 520 is received_k511 and the time of the sum of the survival period KAP600 is the current postponing information V that has arrived in time_n503 authorized start time start_n516 before (or in time with postponement information V_n503), the survival period KAP600 has expired. The peripheral should disable its stored parameters and keys related to this service in a secure way. This may indicate that the deferred information has been directed to a new user. The user identifier 102 may also have been assigned to another user by the subscriber management system. This is shown in fig. 7 b. Received postponement information V_k500 and V_n503 denotes start at the start time_n516 survival period KAP600 has expired, which can be expressed by the formula (end)_k+KAP＜start_n) And (4) showing. Access authorization is not deferred.

Thus, a user whose identifier 102 has failed (also referred to as the original user) will be prevented from re-accessing content using their device after the published user identifier 102 is reassigned.

However, the inevitable fact is that those users who have deferred their subscription but whose devices are unable to receive for a long period of time are therefore unable to use the service. These users should contact the service provider to obtain new user identifiers or to recover disabled parameters and keys for the respective services in their devices, since in this case their original user identifiers 102 are also registered in the subscriber management system.

The above-described method of reassigning user identifiers 102 has a management effect on how the user identifiers 102 for which the question is released can be reassigned. This can limit the required address space in the long term and guarantee optimized packet information. This is not described in conventional digital rights management systems and access authorization systems (e.g. CA or DRM systems), but it can also be used in most systems on the server or user side, i.e. by a controlling computer or by a controlled computer.

The method of the present invention requires a peripheral device that operates as specified and a subscriber management system that operates as specified. The solution does not impose restrictions on the general business model. The present invention addresses the present needs and provides a reliable solution.

Fig. 8 is a block diagram of an embodiment of a system 800 for controlling service access authorization. The system comprises a device 200 for providing authorization information, a first device 100 for controlling service access authorization 104 and a second device 100 for controlling service access authorization 104.

The system 800 is used to first assign a predetermined service dependent user identifier 102 to a first device 100 for controlling service access authorization 104 and to assign it to a second device 100 for controlling service access authorization 104 after the predetermined service dependent user identifier 102 becomes available for reuse. In addition, the system is capable of enabling an authorization for deferring or recovering the service access authorization 104 using the predetermined service dependent user identifier 102 to be valid at most for one of the first device 100 for controlling the service access authorization 104 and the second device 100 for controlling the service access authorization 104, wherein the first device 100 for controlling the service access authorization 104 and the second device 100 for controlling the service access authorization 104 are connected to the device 200 for providing the authorization information 103 to receive the authorization information 103.

The system 800 may transmit the authorization information 103 in a wired or wireless manner, for example, via a digital video or audio broadcasting system, a mobile radio system, a circuit-switched or packet-switched voice or data network, or via an internet protocol system, a GSM, UMTS or CDMA system, a GSM system or a DSL system. The system 800 may also include a plurality of apparatuses 100 for controlling service access authorization 104. The system 800 may be an electronic circuitry and the authorization information 103 may be data information (or referred to as data information) which may be transmitted from the apparatus 200 for providing authorization information 103 to the first apparatus 100 for controlling the service access authorization 104 and the second apparatus 100 for controlling the service access authorization 104 and the further apparatus 100 for controlling the service access authorization.

The service dependent user identifier 102 may be represented by a sequence of bits, wherein the range of values of the service dependent user identifier 102 may for example comprise a range which is smaller than the product of the number of registered users in the system 800 and the number of registered services in the system 800. This means that the number of service dependent user identifiers 102 corresponding to the number of such services in the system 800, i.e. the number of services that a user can use, should be maintained for each user comprising a user equipment without reusing the service dependent user identifiers 102. When the system 800 is fully used, many service dependent user identifiers 102 will be assigned to each user when there is a service registration. The idea proposed by the present invention to reuse the service dependent user identifier 102 will not necessarily keep the maximum number of all possible combinations, but a smaller number will suffice.

The predetermined period 123 or the survival period KAP600 represents an important parameter of the method and system 800 of the present invention. For example, the KAP600 may be predetermined in the apparatus 200 for providing the authorization information 103 and transmitted to the first apparatus 100 and the second apparatus 100 when the service is enabled. However, the KAP600 may also be considered a fixed value for the system 800 or may be determined from known parameters of the system 800. Alternatively, in the system 800, the KAP600 is determined by one of the devices 100 and transmitted from the device to the other devices 100 and 200. Preferably, the system 800 may also assign the service dependent user identifier 102 in time and block the service dependent user identifier 102 for those users to which the service dependent user identifier 102 was last assigned to his user equipment after the service access authorization 104 expires to the predetermined period 123. In this way, the system 800 can prevent a user with an expired service access authorization 104 from accessing the service access authorization 104 of another user with the same service dependent user identifier 102 that has just been reassigned using still existing access data.

In a preferred embodiment, the system 800 is a cryptographic system capable of transmitting the authorization information 103 in an encrypted or partially encrypted manner, for example using a symmetric key, which may be performed using an AES (also referred to as advanced encryption standard) encryption algorithm, a DES (also referred to as data encryption standard) encryption algorithm. The system 800 may be, for example, a digital rights management system according to one of the OMA DRM, ETSI-EURORYPT, or ISMA standards, which have been described above.

The system 800 for controlling service access authorization may connect the device 200 to the first device 100 and the second device 100. The connection may be made through a computer network (e.g., ethernet or IP protocol), which may be implemented in a wired or wireless based manner. For example, the connection may be realized by a cable network of a cable operator, a radio relay system, a satellite radio system, a mobile radio system (e.g. a GSM system or a CDMA system of a UMTS system or a time division multiplex system). The connection may be implemented through a LAN network, a MAN network, a WLAN network, or through a fiber optic transmission network. In addition, the connection may be implemented through a power supply network (also referred to as a power line network) or through an ATM network or by means of a DSL method.

The scheme of the invention can be used for an access authorization system, a conditional access system or a digital rights management system DRM, can be implemented on a server side and can also be implemented on a client side, wherein the server side refers to the side of a control computer, and the client side refers to the side of a controlled computer. In the embodiment shown in fig. 8, the apparatus 800 may be considered, for example, to be on the server side (controlling computer side), and the first apparatus 100 and the second apparatus 200 for controlling the service access authorization 104 are located on the client side (i.e., belong to the controlled side).

Depending on the environment of use, the method of the invention may be implemented in hardware or software. The present invention may be implemented on a digital storage medium, in particular a compact disc or CD, using electronically readable control signals, which may assist a programmable computer system in performing the respective methods. In general, the invention can also be used in a computer program product, comprising program code stored on a machine-readable carrier, for performing the inventive method when said computer program runs on a computer. In other words, the invention can also be implemented as a computer program comprising program code for performing the inventive methods when the computer program runs on a computer.

Claims (31)

1. An apparatus (100) for controlling service access authorization for a user equipment for an access limited service, comprising:

a service access authorization provider (101), the service access authorization provider (101) being configured to set a time period for which a service access authorization (104) is valid in response to authorization information (103) provided with a service dependent user identifier (102), and the service access authorization provider (101) being configured to disable (105) an authorization allowing to postpone or restore the service access authorization (104) using a previous service dependent user identifier (102) when it is determined from the apparatus (100) that the end of a last authorization period (106) of the service access authorization (104) has passed at least a predetermined period (123).

2. The apparatus (100) of claim 1, wherein the service access authorization provider (101) is configured to provide service access authorization (104) for audio services, video services or multimedia services for a pay video system or a driving assistance system on a mobile or stationary mounted device, or data services on a mobile phone, or charging and/or access restricted services on a portable or stationary computer with or without internet access functionality.

3. The apparatus (100) according to claim 1 or 2, wherein the service access authorization provider (101) is configured to disable (105) the authorization allowing the postponement or resumption of the service access authorization (104) using the previous service dependent user identifier (102) in response to the apparatus (100) being powered on, when at least a predetermined period of time has elapsed since the apparatus (100) was powered on from the apparatus (100) when the end time (121) of the last authorization period (107) of the service access authorization (104) was determined.

4. The apparatus (100) of any one of the preceding claims, wherein the service access grant provider (101) is configured to determine the grant period (106) from the received enabling information or deferral information (103) when the device identifier matches the device identifier of the apparatus, and to enable the service access grant (104) when an end time (124) of the grant period (106) is temporally subsequent to a current time and when a period between a start time (122) of the grant period (106) and an end time (121) of a previous grant period (107) of the service access grant (104) determined by the apparatus (100) is shorter than a predetermined period (123), wherein the enabling information or deferral information (103) comprises the device identifier and the service dependent user identifier (102).

5. The apparatus (100) according to claim 4, wherein the service access authorization provider (101) is configured to defer or restore the authorization of the service access authorization (104) for a predetermined period of deferral (123) using the previous service dependent user identifier (102) when the apparatus (100) determines the service access authorization (104) due to the enabling information or deferral information (103).

6. The apparatus (100) of any of the preceding claims, wherein the service access authorization provider (101) is configured to disable the service access authorization (104) after expiration of an end time (124) of the authorization period (106) when the apparatus (100) does not determine a new service access authorization (104) at the end time (124).

7. The apparatus (100) according to any one of the preceding claims, wherein the service access authorization provider (101) is configured to disable (105) postpone or restore authorization for service access authorization using a previous service dependent user identifier (102) by clearing or disabling a parameter or key associated with the service access authorization (104) or with the previous service dependent user identifier (102) from reading or blocking the parameter or key.

8. The apparatus (100) according to any one of the preceding claims, wherein the service access authorization provider (101) is implemented as an electronic circuit.

9. An apparatus (200) for providing authorization information for a user equipment for access restricted services, comprising:

an authorization information generator (202); and

an identifier manager (201),

wherein the authorization information generator 202 is adapted to generate enabling information (103) for enabling the service access authorization (104) or postponing information (103) for postponing the service access authorization (104), the enabling information (103) or the postponing information (103) being provided with the service dependent user identifier (102) provided by the identifier manager (201), and

wherein the identifier manager (201) is configured to leave out (203) the service dependent user identifier (102) unused for at least the predetermined period (123) after expiry of the authorization period (106) for the user equipment with which the service dependent user identifier (102) was last associated, and to release (204) the service dependent user identifier (102) after expiry of the predetermined period (123) to enable reuse by the authorization information generator (202).

10. The device (200) according to claim 9, wherein the authorization information generator (202) is configured to generate information (103) for enabling or postponing audio services, video services or multimedia services or data services for driving assistance systems on mobile or stationary mounted devices or data services on mobile phones or for charging and/or access controlled services on portable or stationary computers with or without internet access functionality.

11. The apparatus (200) according to claim 9 or 10, wherein the authorization information generator (202) is configured to generate the authorization information (103) comprising one or more service dependent user identifiers (102), wherein the service dependent user identifiers (102) are represented by a bit sequence and the authorization information generator (202) is implemented as an electronic circuit, and the authorization information generator (103) is configured to transmit the authorization information (103) comprising the service dependent user identifiers (102) over a limited bandwidth information channel and the identifier manager (201) is implemented as an electronic circuit.

12. The apparatus (200) according to any of claims 9-11, wherein the identifier manager (201) is configured to release the service dependent user identifier (102) to be reusable by another user or another peripheral after expiration of the predetermined period (123).

13. The apparatus (200) according to any of claims 9-12, wherein the identifier manager (201) is configured to reuse the service dependent user identifier (102) for a new subscription of another user or of the same user after a predetermined period (123) has expired since the subscription has ended, after the subscription of the user device with which the service dependent user identifier (102) was last associated ends.

14. The apparatus (200) according to any of claims 9-13, wherein the identifier manager (201) is configured to assign values in the range of three days to three months to the predetermined period (123).

15. The apparatus (200) according to any of claims 9-14, wherein the authorization information generator (202) is configured to generate messages directed to a plurality of receivers.

16. The apparatus (200) according to any of claims 9-15, wherein the authorization information generator (202) is configured for personalizing the enabling information or deferral information (103) such that the service dependent user identifier (102) depends on a device identifier or a service identifier of a device on which the service is running, and the authorization information generator (202) is configured for grouping a plurality of enabling information or deferral information (103) in a way that information (103) of users of the same authorization period (106) are grouped.

17. The apparatus (200) according to any one of claims 9-16, wherein the authorization period (106) is specified by a start time (122) and an end time (123) or by a start time (122) and a duration.

18. A system (800) for controlling service access authorization (104) for an access limited service, comprising:

the apparatus (200) for providing authorization information according to any of claims 9-17;

the first device (100) for controlling service access authorization (104) according to any of claims 1-8; and

second device (100) for controlling service access authorization (104) according to any of claims 1-8,

wherein the system (800) is configured to first associate the predetermined service dependent user identifier (102) with the first device (100) for controlling service access authorization (104) and to associate the predetermined service dependent user identifier (102) with the second device (100) for controlling service access authorization (104) after it has been released for reuse;

the system (800) is configured to defer or restore authorization of the service access authorization (104) using the predetermined service dependent user identifier (102) at most valid in one of the first device (100) for controlling the service access authorization (104) and the second device (100) for controlling the service access authorization (104), wherein the first device (100) for controlling the service access authorization (104) and the second device (100) for controlling the service access authorization (104) are connected to the device (200) for providing authorization information (103) to receive the authorization information (103).

19. The system (800) of claim 18, wherein the system (800) is configured to transmit the authorization information (103) in a wired or wireless manner over a digital video or audio broadcasting system, a mobile radio system, a circuit-switched or packet-switched voice or data network, or an internet protocol system, a GSM, UMTS or CDMA system, a GSM system or a DSL system.

20. The system (800) according to claim 18 or 19, wherein the system (800) is configured to use the same predetermined period (123) for the device (200) for providing authorization information (103), the first device (100) for controlling the service access authorization (104) and the second device (100) for controlling the service access authorization (104), and wherein the system (800) is configured to transmit the predetermined period (123) when the service is enabled, or to set the transmission predetermined period (123) to a fixed amount of the system (800), or to determine the transmission predetermined period (123) from known parameters of the system (800).

21. The system (800) according to any of claims 18-20, wherein the means (200) for providing authorization information (103) is configured for providing a service dependent user identifier (102), the service dependent user identifier (102) comprising a range of values smaller than the product of the number of registered users in the system (800) and the number of registered services in the system (800).

22. The system (800) according to any of claims 18-21, wherein the identifier manager (201) of the apparatus (200) for providing authorization information (103) is configured for temporarily assigning the service dependent user identifier (102), and wherein the system (800) is configured for preventing the service dependent user identifier (102) of the user device with which the service dependent user identifier (102) was last associated after the service access authorization (104) expires to the expiration of the predetermined period (123).

23. The system (800) according to any of claims 18-22, wherein the system (800) is configured to employ an encryption algorithm to partially or fully encrypt the authorization information (103) with a key and to transmit the authorization information (103) in a partially or fully encrypted manner.

24. The system (800) of claim 23, wherein the system (800) is configured to transmit the authorization information (103) in a partially or fully encrypted manner using an encryption method.

25. The system (800) according to any one of claims 18-24, wherein the system (800) is configured to identify the authorization information (103) using electronic authentication or electronic signature.

26. The system (800) of claim 25, wherein the system (800) transmits the authorization information (103) with a message authentication code.

27. The system (800) according to any one of claims 18-26, wherein the authorization information (103) conforms to one of OMA DRM, ETSI-eurocpt, or ISMA standards.

28. The system (800) according to any of claims 18-27, wherein a user with an expired service access grant (104) is prevented from being able to access, through the still existing access data, a service access grant (104) of another user using the same service dependent user identifier (102) transmitted after the service access grant (104) has expired.

29. A method (300) for controlling service access authorization for an access limited service, the method (300) comprising:

determining a time period for which a service access authorization (104) is valid in response to authorization information (103) provided with a service dependent user identifier (102);

-disabling (105) delaying or resuming the authorization of the service access authorization (104) using the previous service dependent user identifier (102) when at least a predetermined period has elapsed since the end time of the last authorization period (107) of the service access authorization (104).

30. A method (400) for providing authorization information (103) for access to a restricted service, the method (400) comprising:

-generating authorization information (103) for enabling service access authorization (104) or deferral information (103) for deferring service access authorization (104), wherein the enabling information (103) or deferral information (103) is provided with a service dependent user identifier (102) provided by an identifier manager (201);

not using the service dependent user identifier (102) for at least a predetermined period (123) after expiry of an authorization period (106) for the user equipment with which the service dependent user identifier (102) was last associated; and

releasing the service dependent subscriber identifier (102) after expiration of the predetermined period (123) to generate new enabling information (103) or deferral information (103).

31. A computer program comprising a program code for performing the method according to claim 29 or 30 when the computer program runs on a computer.