Abstract:
The present invention relates to a method for providing content in a communication system. The method comprises encoding content to a first part and a second part. Furthermore, the method comprises protecting the second part of the content against unauthorised use. Furthermore, the method comprises transmitting the content to user equipment associated with an identity module. The present invention relates also to a method for obtaining content in user equipment in a communication system. The method comprises receiving content encoded to a first layer and a protected second layer. Furthermore, the method comprises requesting for opening the protection of the second layer, receiving opening means and opening the protection of the second layer using the opening means interacting with an identity module associated with the user equipment. Furthermore, a network element and user equipment are configured to execute the method.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention relates to communication systems, and more particularly, but not exclusively, to providing content in a communication system.  
       BACKGROUND OF THE INVENTION  
       [0002]     A communication system can be seen as a facility that enables communication sessions between two or more entities such as user terminal and/or other nodes associated with the communication system. Users of a communication system may be offered and provided numerous services, such as two-way or multi-way calls, data communication or multimedia services or simply an access to a network, such as the Internet. The services may be offered by an operator of the communication system or by an external service provider.  
         [0003]     Examples of communication systems may include fixed line communication systems, such as a public switched telephone network (PSTN), wireless communication systems, e.g. global system for mobile communications (GSM), general packet radio service (GPRS), universal mobile telecommunications system (UMTS), wireless local area network (WLAN) and so on, and/or other communication networks, such as an Internet Protocol (IP) network and/or other packet switched data networks. The IP Multimedia Subsystem (IMS) is an example of a system providing multimedia services. Various communication systems may simultaneously be concerned in a connection.  
         [0004]     An end-user may access a communication network by means of any appropriate user equipment (UE), for example a mobile terminal, such as a mobile station (MS), a cellular phone, a personal digital assistant (PDA) or the like, or other terminals, such as a personal computer (PC), or any other equipment operable according to a suitable network protocol, such as a wireless applications protocol (WAP) or a hypertext transfer protocol (HTTP). The user equipment may support, in addition to call and network access functions, other services, such as short message service (SMS), multimedia messaging service (MMS), electronic mail (email), Web service interface (WSI) messaging and voice mail. A mobile terminal may comprise an identity module, for example a subscriber identity module (SIM), a UMTS subscriber identity module (USIM) or a wireless identity module (WIM). The identity module is suitably a device allowing transfer of subscription data from one UE to another and may be shortly referred to as a subscriber. Respectively, a mobile station without the identity module may be referred to as a Mobile Equipment (ME).  
         [0005]     Using the MMS, or multimedia messaging, it is possible to provide various content services, such as news services, sound clips, video clips, and so on, from a server to UE. MMS typically employs Wireless Application Protocol (WAP) on a circuit switched or packet switched bearer. However, there may be numerous difficulties or drawbacks in providing content using the MMS. For example, the users may perceive as relatively high the charging of content services over wireless connections with relatively slow speeds. Small displays of some types of mobile stations may increase a threshold in ordering content provided using the MMS and render these services unattractive.  
         [0006]     A content provider may, for instance, attempt to attract users or customers by providing free samples or “teasers”. The free samples or teasers may provide only a part of the content or the entire content with a reduced quality. This should attract users to order a sample and to become keen on ordering the whole content or a better quality version, which are chargeable.  
         [0007]     To charge for content, a content provider may run a private charging procedure or may rely on a cellular network operator. Charging via a telephone bill with the aid of the network operator may be a preferred solution due to its ease and low running costs. The content provider may itself run a cellular network or the content provider may make a charging agreement with the network operator. Running a cellular network may not be feasible for many content providers. Having a charging agreement with the network operator competes with the interest of the network operator to provide the content services itself.  
         [0008]     If only a part of content is provided as a sample, the user may not be easily attracted to test the service at all, at least not more than once. Even if the full content with lower quality was first provided as a sample, the user may consider the gain from getting the content in better quality not worth the trouble of ordering and waiting for the full content to download.  
         [0009]     Patent Publication U.S. Pat. No. 5,933,498 presents an arrangement for controlling access and distribution of digital property, wherein protected rules are distributed with data and the access to the data is controlled by the protected rules. Patent publication U.S. Pat. No. 5,509,070 presents an arrangement where a computer program is delivered with a software tool, which provides password functionality bundled in the computer program. The arrangement of U.S. Pat. No. 5,509,070 works only with executable content since the digital rights management functionality is provided by the content itself. U.S. Pat. No. 5,509,070 separates content delivery from charging, which may suffice for charging computer programs that a user buys rarely, perhaps few times a year. However, separating the content delivery from the charging may not suit well for news clips or pieces of music or similar content services that a user is hoped to buy often, for example on a daily basis.  
       SUMMARY OF THE INVENTION  
       [0010]     In accordance with an aspect of the invention, there is provided a method for providing content in a communication system. The method comprises encoding content to a first part and a second part. Furthermore, the method comprises protecting the second part of the content against unauthorised use. Furthermore, the method comprises transmitting the content to user equipment associated with an identity module.  
         [0011]     In accordance with a further aspect of the invention, there is provided a method for obtaining content in user equipment in a communication system. The method comprises receiving content encoded to a first layer and a protected second layer. Furthermore, the method comprises requesting for opening the protection of the second layer, receiving opening means and opening the protection of the second layer using the opening means interacting with an identity module associated with the user equipment.  
         [0012]     In accordance with a further aspect of the invention, there is provided a network element in a communication system configured to encode content to a first part and a second part, to protect the second part of the content against unauthorised use and to transmit the content to user equipment associated with an identity module.  
         [0013]     In accordance with a further aspect of the invention, there is provided user equipment configured to receive content encoded to a first part and a second complementary part, to request for opening the second part, to receive opening means and to open the protection of the second part using the opening means interacting with an identity module associated with the user equipment. Embodiments of the invention allow delivering content in two parts, namely a first part, also called a basic part, and a second part, also called a complementary part, the second part being protected against unauthorised use. Both parts are delivered together so that only the first part may be used without specific restrictions and the rights for the second, protected part can be obtained, such as bought, separately. The user need not suffer any further download time on deciding to purchase the protected or locked portion. After the decision to purchase the locked portion is made, the locked portion may already be received or is being received so that only signalling for obtaining a key to use the locked portion may be needed. On slow communications links, this may provide significant advantages. Particularly, in case the content is delivered as a part of a subscribed service that sends regular updates this may be advantageous, as the initial longer content provision may go completely unnoticed to the user.  
         [0014]     The embodiments of any one aspect also apply to various other aspects of the invention as appropriate. In sake of briefness, the embodiments have not been repeated in connection with every aspect of the invention. A skilled reader will appreciate the advantages of the various aspects based on the advantages of an aspect of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     The invention will now be described in further detail, by way of example only, with reference to the following examples and accompanying drawings, in which:  
         [0016]      FIG. 1  shows an example of a system in which the embodiments of the invention may be implemented;  
         [0017]      FIG. 2  shows an exemplary authentication centre;  
         [0018]      FIG. 3  shows exemplary user equipment; and  
         [0019]      FIG. 4  shows a signalling chart illustrating an embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0020]     FIGS.  1  to  3  show an exemplary system  1 , wherein  FIG. 1  shows a block diagram of the system  1  as a whole and  FIGS. 2 and 3  show block diagrams of exemplary authentication centre (AuC)  22  and user equipment (UE)  12 , respectively.  
         [0021]     System  1  includes a communication network (CN)  10 , User Equipment (UE)  12  and a Service Provider (SP)  14 . The UE  12  comprises a Mobile Equipment (ME)  16  and a Subscriber Identity Module (SIM)  18 . The CN  10  comprises an Authentication, Authorisation and Accounting server (AAA)  20 , an MMS Service Centre (MMSC)  34 , a WAP Gateway (GW)  36  and a WAP origin server  38 .  
         [0022]     The AAA server  20  comprises an Authentication Centre (AuC)  22 , an embodiment of which is shown more in detail in  FIG. 2 . The AuC  22  is capable of issuing authentication codes, such as GSM triplets  24  each consisting of a challenge (RAND)  26  and two data items derivable from the RAND  26 , namely Signed RESponse (SRES)  28  and a session key (K c )  30 . These two items, SRES and K c , are derivable by particular encryption algorithms (A 3   227  and A 8   228 ) from a shared secret K i    32  specific to the particular subscriber represented by the SIM  18  of the UE  12 . Only the SIM  18  and the AuC  22  should know the shared secret K i    32 , as the operation of the AAA  20  depends upon K i  and the algorithms A 3  and A 8  not leaking to other parties.  
         [0023]     The AuC comprises a database  221  comprising the shared secrets K i    32  of n+1 subscribers presented as fields k i,1 , k i,2 , k i,3 , . . . k i,n , k i,n+1 . The AuC  22  also comprises a Central Processing Unit (CPU)  222 , a memory (MEM)  223  containing a Random Access Memory (RAM)  224  as a work memory and a Read Only Memory (ROM) or non-volatile i.e. persistent memory  225 . The AuC  22  also comprises an Input/Output (I/O) block  226  and authentication algorithms A 3   227  and A 8   228  either common for the n+1 subscribers as depicted in  FIG. 2  or, alternatively, separately for each subscriber in respective fields of the database (not shown). The ROM  225  comprises computer code or software for controlling the CPU  222 . The CPU is connected to the memory  223 , the I/O  226  and the database  221 . Under operation, the AuC  22  is capable of obtaining GSM triplets or other authentication code for a given subscriber as identified by a subscriber specific identifier, such as an International Mobile Subscriber Identification (IMSI), and of yielding, responsively, GSM triplets  24 .  
         [0024]     The GW  36  may be a packet and/or circuit switched data enabled gateway such as a GPRS Support Node that supports WAP 1.1 User Agent Profile (UAProf) and hence can store a UAProf. The UAProf provides an advantageous capability for the UE  12  to inform the CN  10  of capabilities of the UE and/or user preferences including a new attribute referred hereinafter as refinement DRM attribute. The refinement DRM attribute is suited to advice the CN  10  of the UE  12  supporting particular digital rights management procedure illustrated with further detail in this exemplary description.  
         [0025]     User equipment according to an embodiment of the invention is shown in  FIG. 3 . The UE  12  may contain a Mobile Equipment (ME) part  16  and a SIM  18  in a manner known, for instance, from GSM telephones or mobile stations. The ME  16  comprises a radio transceiver  161  coupled with a Central Processing Unit (CPU)  162 . The CPU  162  is further connected with a User Interface (UI)  166  and a memory (MEM)  163 . The memory  163  contains a Random Access Memory (RAM) or work memory  164  and a Read Only Memory (ROM)  165 . The ROM is typically a non-volatile or persistent memory suitable for long-term storing of data, such as operating system and computer program code (software) for controlling the operation of the CPU  162 . The CPU has further an access to the SIM  18  as illustrated by a direct connection. It should be understood that the normal Application Specific Integrated Circuits (ASIC) and other normal hardware implementation not necessary to understand the present invention have been omitted. For example, normally there would be an ASIC next to each processor. It should also be understood that any of the blocks presented might be provided within a common chip.  
         [0026]     The SIM  18  comprises the authentication functions used in the mobile communication systems, such as the GSM, UMTS or CDMA 2000. Particularly, the SIM  18  may comprise a shared secret K i    181 , any algorithms necessary to authenticate the SIM with a GSM operator, such as A 3   182  or A 8   183 , and a processor  184 , such as a Digital Signal Processor DSP, that suitably controls the operation of the SIM  18 . The processor  184  is connected to the shared secret K i    181 , algorithms  182  and  183  (either hardwired or software code representing the shared secret and/or algorithms) and memory  185 .  
         [0027]     In a normal operation, the CPU  162  controls the operation of the ME  16  so that it communicates as specified in the respective telecommunications standards such as GSM, UMTS or CDMA 2000. When implementing the present invention, the CPU  162  may receive signals requiring co-operation with the SIM  18 . In such a case, the CPU  162  will signal with the SIM  18  that will use its own processor and secret data in order to respond to the CPU  162  with an authentication code, such as a GSM triplet comprising a challenge RAND  26  with respective SRES  28  and session key K c    30 , as described in connection with  FIG. 2 .  
         [0028]     It should be appreciated that  FIGS. 1-3  only present exemplifying embodiments whereas numerous variations are available in the technical implementation of the invention only limited by the appended claims. For instance, the communication network  10  in  FIG. 1  may be a GSM network. Alternatively, the network may be another Time Division Multiple Access (TDMA) based network such as a Personal Digital Communication (PDC) network, a Code division Multiple Access (CDMA) based network, such as an IS-95 or a Wideband CDMA (W-CDMA) network, or any other appropriate communication network. In an embodiment, the communication network  10  is provided at least in part by an Internet Protocol (IP), network. The SIM may be, but need not be, a detachable module. In an alternative, similar challenge-response capability may be built into the UE  12 . The WAP Origin server  38  may be contained in the CN  10  as shown in  FIG. 1 . In an alternative, the WAP Origin server  38  may be distributed and accessible to the WAP Gateway, for instance, via the service provider  14 .  
         [0029]      FIG. 4  shows a signalling chart illustrating an embodiment of the invention performed using Multimedia Messaging Service (MMS) presently supported by various mobile telecommunication networks, such as various GSM, GPRS and UMTS networks.  FIG. 4  illustrates some major signals exchanged in the system  1  of  FIG. 1 . The process exemplified by  FIG. 4  may split in two stages: delivery of the content with partial protection in stage  1  and obtaining the rights to use the whole content including the protected part in stage  2 .  
         [0030]     Stage  1  may begin either on user instruction or it may be based on a preordered service that may invoke new content delivery on predetermined intervals or on meeting certain criteria (such as a goal being made in a soccer match). A user invoked case is described in the following. On instruction of a user, the UE  12  initiates a process for obtaining desired content. The UE  12  will attach to a communication network service, such as a GPRS service, and provides a UAProf or Capability and Preference Information (CPI) data to the gateway  36  in signal  201 . This signal contains an attribute refinement DRM in addition to the normal UAProf contents. The UAProf is based on Wireless Application Protocol (WAP) discussed in the Wireless Application Group User Agent Profile Specification WAG UAPROF version 10 Nov. 1999. The User Agent Profile (UAProf) specification extends WAP 1.1 to enable the end-to-end flow of a User Agent Profile (UAProf), also referred to as Capability and Preference Information (CPI), between the WAP client (i.e. User Agent in the MMS terms or User Equipment), the intermediate network points, and an origin server  38  (such as content provider&#39;s server). This UAProf or CPI may include, but is not limited to, hardware characteristics (screen size, colour capabilities, image capabilities, manufacturer, and so on), software characteristics (operating system vendor and version, support for Mobile station application Execution Environment (MExE), list of audio and video encoders, and so on), application and/or user preferences (browser manufacturer and version, markup languages and versions supported, scripting languages supported, and so on), WAP characteristics (Wireless Markup Language (WML) script libraries, WAP version, WML deck size, and so on), and network characteristics (bearer characteristics such as latency and reliability, and so on).  
         [0031]     The same WAG UAPROF specification further discloses in paragraph 5.1 “Client Device” that the CPI consists of information gathered from the device hardware, active user agent software, and user preferences. In many cases, much of this information must be pre-installed directly on the device, possibly in the firmware. For instance, the device may publish a single Uniform Resource Identifier (URI) that points to default device capability information made available by the device manufacturer. Similarly, the user agent may publish a single URI that points to default software information made available by the software developer. Hence, existing MMS environment may support conveying various data to the MMS network.  
         [0032]     Armed with the UAProf, the GW  36  is ready to serve the refinement DRM attribute to any WAP content server, such as the WAP origin server  38  providing news, ring-tone, gaming or other service related content. Signal  202  may represent a request for content, such as a so-called GET method using, for example, the HTTP. The UE  12  may request for content from the origin server  38  by means of the GET method. Responsive to signal  202 , the origin server  38  may request and obtain the refinement DRM attribute from the WAP gateway, signals  203  and  204  respectively. The DRM attribute (and other UAProf data) may also be provided before the signal  202 , for instance, as part of opening a Wireless Session Protocol (WSP) session with the origin server.  
         [0033]     Once the origin server  38  has received a request to the content and the refinement DRM attribute, the origin server  38  may be prepared to provide the content in a form wherein a first part is ready for use and a second part is protected by a cryptographic measure such as encryption with a code that will be provided only against a predetermined condition, such as a payment. Signal  205  may provide the origin server  38  with the identification of the UE  12 , such as IMSI, from the GW  36  in case the identification of the UE  12  is not yet known by the origin server  38 . Signal  206  may then provide the identification to the AAA server  20 . The AAA server verifies that the origin server  38  is approved or trusted by the operator and responds to the origin server  38  with signal  207  containing an authentication code, such as one or more GSM triplets  24 .  
         [0034]     The origin server  38  then organises, either internally or using an external sub-service provider, the content being provided in a two-part format supported by the UE  12  as indicated by the UAProf. The Origin server  38  also organises the protection of the second part by the authentication code, for example at least with one or more item of the triplet other than the challenge RAND, either internally or using an external protection sub-service provider. In an alternative, the origin server  38  can invoke organising the data in two parts already before the signal  207 . In an embodiment, the origin server  38  may store the data in a two-part form in order to accelerate its operation and reduce processing load.  
         [0035]     In a preferred embodiment of the invention, the delivery of the content is arranged using the WAP browser. However, it may equally be preferred to subscribe to a service that provides regularly new content, e.g. a news service or a music club, wherein the user need not actively retrieve data but is, instead, provided with a push-type delivery mechanism or the like. The MMS is particularly suitable for this, as an efficient and versatile standard with a substantial user base.  
         [0036]     In signal  208 , the origin server  38  may despatch to the MMSC  34  by means of the MMS the two-part content addressed to the subscriber identified by the SIM  18 .  
         [0037]     The MMSC  34  may next exchange typical MMS signalling  209 ,  210  including MMS notification (signal  209 ), MMS notification acknowledgment and MMS retrieve request (signal  210 ) before the MMSC  34  actually delivers the two-part content to the UE  12  in a MMS retrieve response in signal  211 . The two-part content is now only partly usable by the UE  12 . The first, i.e. the basic, part may be used without restrictions and the second, i.e. the complementary, part only by opening the protection. In order to facilitate the purchase of the protected second part, the MMS retrieve response carrying the two part content in signal  211  may contain a new media component comprising purchase data sufficient for the UE  12  to obtain the challenge that enables the SIM  18  of the UE  12  to obtain the necessary credentials to decode the second part for the own use of the UE  12 . The purchase data preferably contain use limitations such as the number of allowed use, whether further delivery is allowed and to which group or how many times delivery is allowed or the period of such allowance and also suitably the price of the purchase. Once the user of the UE  12  desires to use the second, protected part, for instance, to get a ring-tone entirely or to enable taking into use a ring-tone in the UE  12 , the user may invoke the stage  2  of the content provision process as shown in the  FIG. 4 .  
         [0038]     The UE  12  may send a signal  212  to the content provider, such as the origin server  38 , requesting opening the second part. The content provider responsively invokes a charging process with the AAA  20  represented by signals  213  to  215  wherein the content provider signals a UE  12  specific security item (signal  213 ) verifying that the subscriber or SIM  18  has approved the transaction together with the price being charged, the AAA  20  sends an OK signal  214 , or a not OK signal, and the origin server  38  acknowledges with signal  215 .  
         [0039]     After a successful charging process, i.e. when signal  214  was OK, the origin server  38  sends a signal  216  carrying the challenge  26  to the UE  12 . In the UE  12 , the ME  16  receives the challenge  26  and passes the challenge to the SIM  18 . The SIM  18  derives the response and the session key (SRES, K c ) of the GSM triplet  24  and uses one or both of them to decode the second part of the content. The decoding may contain decryption. In that case, only a UE comprising the particular SIM  18  can decode the second part with the data provided by the origin server  38 . Even if another UE were able to capture the data exchange between the-origin server  38  and the UE  12 , only the first part would be usable.  
         [0040]     The description above is only a streamlined example and various other signals may be provided or some of the signals above can be omitted. For instance, if so desired, the UE  12  may be requested to prove the desire to purchase the content using its SIM cryptography before the AAA server  20  can proceed with signals  213  to  215 . This may be performed by the ME  16  computing a RAND equivalent hash code out of the purchase data, feeding the RAND equivalent hash code to the SIM  18 , receiving a corresponding SRES and K c , sending the SRES to the origin server  38 , the content server  38  passing the SRES and the purchase data to the AAA  20 , the AAA computing the RAND equivalent code and comparing respective SRES with the received SRES and if matching, accepting the transaction and charging the subscriber&#39;s normal telecommunications account. As a further security measure, the AAA  20  may subsequently return a hash code of the K c  for the equivalent RAND to the UE  12  via the origin server  38  thus ensuring to the UE  12  that the origin server  38  indeed has access to its own AAA server  20  and not just fabricating data to conclude the shared secret of the SIM  18 . This aforementioned further verification process also allows the normal telecommunications operator to store the transaction details for subsequent use in case the service provider would fail to provide the content as promised by advertising, for instance.  
         [0041]     The user equipment is preferably configured such that it allows forwarding the content over a cellular network in a protected state, namely with the unprotected first layer and the protected second layer. If the content proves to be interesting, the content may be transmitted to further user equipment. In the further user equipment, the protected second layer may be decrypted as explained above.  
         [0042]     Preferably, the user equipment should not be able to store the unprotected, such as decrypted, content, but only to open the second layer to a volatile memory. Preferably, any transmission, such as infrared (IR) or Bluetooth (BT) transmission, is prevented while the second layer is presented in an unprotected state. If the user equipment was allowed to store the unprotected content, the content could be copied to a PC or transmitted over a local link.  
         [0043]     In an embodiment, the UE  12  may be trusted to obey any use restrictions imposed by the purchase data such as only present the content for a predetermined number of times, period of time or to only pass it to a set number of other users (zero to any integer) and after that preferably delete any data allowing the unprotection of the second part. This may be advantageous for both the telecommunications operator and the content provider, even if the purchase would not follow. The telecommunications operator may get data transfer revenues and a chance to receive an offer. Each time content is delivered a user may choose to pay. The higher the frequency of content delivery, the higher the number of paid deliveries may be even when assuming that only a small portion of all deliveries results in a purchase. It may also be in the interests of both the telecommunications operator and the content provider to encourage or at least allow local copying of the content with the second part being protected. First, the ability to further share the content may encourage to obtain the content in the first place, particularly when the users are getting accustomed to the new data services. Second, the sharing the content may provide the best possible promotion to the service, free recommendation from a happy user.  
         [0044]     Whilst the UE  12  may be trusted not to share the content as unprotected, a small portion of fraudulently redistributed content may have little effect in business where the content expires shortly, such as news and sports commentary. In an embodiment, the service provider&#39;s copyright notice may provide an efficient tool to enforce any illegal content redistributors to stop infringing acts.  
         [0045]     The configuration of the user equipment may be based on an add-on software or middleware, such as a Java program, or by ROM-based integrated software. In configuration of accessing the identity module, it should be ensured that other applications are not allowed to access an encryption engine of the identity module, for example to prevent various brute-force attacks by the other applications.  
         [0046]     The use of the identity module in locking and unlocking the protected second layer of the content that is originally delivered entirely with only a small transmission fee may make the provision of cheap content very appealing. It may reduce the psychological threshold to order such content, since the charging may be performed via a telephone bill. The charge for the content is separated from the charge for the transmission so that the user may have absolute transparency to the costs and see two small fees rather than one larger.  
         [0047]     Embodiments of the invention may provide new means of delivering content services to user equipment. A unique auto-symbiotic business relationship between the content provider, operator and user may be created in which a true win-win-win can be met. The user only may have to pay in form of slightly longer downloading times and associated costs as the entire content is always downloaded. However, the same extra downloading may benefit simultaneously the operator of the network. The downloading of the entire content may make it very attractive to actually unlock the full content or enhancement layer since the provision of high quality content can then take place in a matter of seconds rather than minutes. The use of the identity module and capability negotiation may provide an optimised experience with individual encryption such that other legitimate terminals are unable to use the content.  
         [0048]     Although the invention has been described in the context of particular embodiments, various modifications are possible without departing from the scope and spirit of the invention as defined by the appended claims. It should be appreciated that whilst embodiments of the present invention have mainly been described in relation to mobile user equipment such as mobile terminals, embodiments of the present invention may be applicable to other types of user equipment that may access communication networks. Furthermore, the communication system may be any appropriate communication system, even if reference has mainly been made to mobile communication systems.