Generic key-decision mechanism for gaa

[0001] The invention relates to a generic mechanism for an application server which determines which of the GAA (Generic Authentication Architecture) keys will allow easy integration of additional application servers by extending the existing USS (User Security Settings) standard.

2. Description of the Related Art [0002] Pre-authorization (i.e. bootstrapping) in 3GPP (Third Generation Project Partnership) of GAA (Generic Authentication Architecture) is based on the AKA (Authentication and Key Agreement Protocol). Depending on the mobile terminal, for example a mobile phone and the Integrated Circuit Card (UICC) of the UMTS (Universal Mobile Telecommunications System) or the subscriber's identity module entered into the mobile terminal, the GAA (Generic Authentication Architecture) 3GPP might have the following keys: Ks int NAF, Ks_ext_NAF and KsNAF. Currently, the number of services using GAA is quite small and determining which key to use, in the case of a given smart card or subscriber identity module, can be entered directly on the NAF server (Network Application Function), which offers the user a given service. However, this type of server introduction is not scalable enough or easy to manage in the event of changes, such as new uses and changes or upgrades of existing services, or the user obtaining a new smart card. NAF changes or updates require manual configuration, which is extremely difficult if the NAF is not in the user's or subscriber's home network, but in a third party network.

[0003] The key Ks int NAF is used to secure the HTTPS (Hypertext Transport Protocol) between the smart card or subscriber identity module and the NAF application server. The application can be present on a smart card or subscriber identity module, and the mobile terminal can only be used as a modem. This mechanism can serve as an alternative to current OTA SMS configuration messages to download new updates or other types of SAT applications.

[0004] Currently, the only application of the Ks int NAF key is MBMS (Multimedia Broadcast / Multicast Service). In MBMS, NAF is configured according to the definition in TS33.246 3GPP specification, attached here as Annex A, the content of which has been introduced by reference. In MBMS, the choice of which key to use is defined based on the description of specific keys in the TS33.246 specification. Therefore, in this case, no key selection mechanism is required because the key is entered directly into NAF, which offers the MBMS service to the user.

[0005] A further state of the art is: 3GPP DRAFT; S3-030729, "UE triggered unsolicited push from BSF to NAFs" NOKIA and 3GPP TS 33.220 version 6.4.0 release 6; Generic bootstrapping architecture (GAA); ETSI TS 133 220.

Summary of the Invention [0006] The invention is defined in the appended claims.

[0007] According to an embodiment of the invention, a method of providing a generic mechanism for a web application server is provided. The method includes receiving a request from the user equipment to provide authorization information for the network application function. The method includes specifying a generic authorization architecture key to integrate additional network application servers by extending the existing user security standard. The method further includes providing authorization information for the functions of the web application.

[0008] According to an embodiment of the invention, a device is provided that provides a generic mechanism for a network application server. A receiving means for receiving a request from the user equipment to provide authorization information for the function of the web application. A determining agent for determining the generic authorization architecture key to integrate additional web application servers by extending the existing user security standard. The first delivery means to provide authorization information for the functions of the web application.

[0009] According to an embodiment of the invention, a device is provided that provides a generic mechanism for a network application server. The receiver receives requests from the user equipment to provide authorization information for the function of the network application. The determining unit defines the key of the generic authorization architecture to integrate additional web application servers by extending the existing user security settings standard. The delivery unit provides authorization information for the functions of the web application.

Brief description of the drawings [0010] The accompanying drawings, which have been introduced here for further explanation of the invention, form part of the description and present examples of the embodiment of the invention, and together with the description explain the advantages and principles of the invention, in which:

FIG. 1A shows a device providing a generic mechanism for a network application server, according to an embodiment of the invention;

FIG. IB illustrates an example network architecture in which the function of the network application is in a visited network, according to an embodiment of the invention;

FIG. 2 illustrates a device providing a generic mechanism for a network application server, according to an embodiment of the invention;

FIG. 3 illustrates a method providing a generic mechanism for a network application server according to an embodiment of the invention; and

-3FIG. 4 illustrates a method providing a generic mechanism for a network application server according to another embodiment of the invention.

Shortcut table [0011]

3GPP - 3^rd Generation Partnership Project [third generation partner project]

3GPP2 - 3^rd Generation Partnership Project 2 [3rd generation partner project] ACM —Address Complete Message

AKA - Authentication and Key Agreement [key authorization and agreement]

Auth -Authentication [authorization]

AUTHR —Authentication Response [authorization reaction]

AVP - Attribute-Value-Pair [attribute-value-pair]

BS —Base Station [base station]

BSC —Base Station Controller [base station controller]

BSF —Bootstrapping Server Function [bootstrapping server function]

BTS —Bas e station Transceiver Subsystem [base station transceiver subsystem]

CK - Confidentiality Key [confidential key]

CM - Cellular Message [cell message]

GAA - Generic Authentication Architecture [generic authorization architecture]

GBA - Generic Bootstrapping Architecture [generic bootstrapping architecture]

GBA U - GBA with UICC-based enhancements [BGA with improvements based on UICC]

GUSS - GBA User Security Settings [GBA user security settings]

HSS - Home Subscriber Server [home subscriber server]

HTTP - Hypertext Transport Protocol [protocol for sending hypertext documents]

HTTPS - Secured Hypertext Transport Protocol [secured protocol for sending hypertext documents]

IK - Integrity Key [integration key]

IMS —IP Multimedia Subsystem [IP multimedia subsystem]

IMSI — International Mobile Subscriber Identity [international identity of a mobile subscriber]

-4IP — Internet Protocol

ISIM - IMS SIM card [SIMIMS card]

Kc - Ciphering Key [encryption key]

Ki —Individual Subscriber Authentication Key [individual subscriber authorization key]

Ks - Key Material

KsintNAF - Derived key in GBAU which remains on UICC [A7wcz resulting in GBAU, which remains on UICC]

Ks_ext_NAF - Derived key in GBA U [result key in GBA U]

KsNAF — Derived Key in GBA ME [result key in GBAME]

MAP —Mobile Application Part [part of the mobile application]

MBMS - Multimedia Broadcast / Multicast Service

ME - Mobile Eqipment [mobile equipment]

MIN —Mobile Identification Number [mobile authorization number]

MNO - Home Mobile NetWork Operator [home mobile network operator]

MO —Mobile Originated [mobile]

NAF - Network Application Function

NE - Network Element [network element]

OTA — Over The Air

PDSN —Packet Data Service Node [packet data service node]

PLC — Private Long Coda [long private code]

PLCM -PLC Mask

PSTN —Public Switched Telephone Network

RAN — Radio Access Network [radio network]

RAND —Random Challenge Data

SAT —SIM Application Toolkit

SIM —Subscriber Identity Module [subscriber identity module]

SMS —Short Message Service [short message services]

UE - User Eąuipment [user equipment]

UICC - UMTS Integrated Circuit Card [UMTS integrated card]

-5UMTS - Universal Mobile Telecommunications System [universal mobile telecommunications system]

USIM —Universal SIM card [universal SIM card \

USS - User Security Settings [user security settings]

Ub —Bootstrapping air interface (from UE to BSF) [wireless bootstrapping interface (from UE to BSF)]

Zh —HSS interface from BSF [HSS interface from BSF]

Detailed Description of Preferred Embodiments [0012] 3GPP is the proposed authorization infrastructure (3GPP TS 33.220, incorporated herein as Annex B, the content of which is incorporated by reference). This infrastructure can be used to run the application functions on the network side and on the user side to communicate in situations where the network side and user side could not otherwise connect. This function is called "application security bootstrapping" or more generally simply "bootstrapping".

[0013] The general principle of bootstrapping is that the generic BSF (bootstrapping server function) allows user equipment (UE) to authorize and reconcile session keys. Such authorization may be based on AKA (authentication and key agreement). By launching AKA, the mobile terminal and the network authorize each other and agree on the keys, primarily the confidentiality key (CK) and the integrity key (IK). After authorization, UE and NAF (network application function), which can also be called a service provider, can support some application-specific protocol in which message authorization is based on session keys agreed between UE and BSF.

[0014] The bootstrapping function is not dependent on any particular function of the network application. The server implementing the bootstrapping function must have operator confidence and be able to support authorization vectors. The functions of the web application can be supported by the operator's home network, visited network or third party network.

[0015] FIG. IA illustrates an example network architecture according to an embodiment of the invention. The network architecture includes user equipment (UE) 100, at least one network application function (NAF) 102, bootstrapping server function (BSF) 104 and home subscriber system (HSS) 106. BSF 104 and HSS 106 are part of the mobile home network operator (MNO) 108. UE 100 connects to MNO 108 according to well-known mobile communication techniques.

[0016] NAF 102 is located in the network element, under the control of MNO 108, for example BSF can also be located in the network element and be controlled by MNO 108. Thus, for practical reasons, each NAF 102 and BSF 104 can be considered as network element.

[0017] As shown in FIG. IA, UE 100 communicates with NAF 102 via interface Ua 110. UE 100 communicates with BSF 104 via interface Ub 112. NAF 102 communicates with BSF 104 via interface Zn 114. BSF 104 communicates with HSS 106 via interface Zh 116.

[0018] NAF 102 can be provided in another separate network. For example, as shown in FIG. IB, an example network architecture is located in NAF 102 in a visited network. In the event that the UE 100 has contacted the NAF 102, which is served in a different network than the home network, the NAF 102 visited will use the Diameter proxy (D-Proxy) 118 of the NAF network to communicate with the subscriber's BSF (i.e. home BSF) 104 . NAF 102 communicates with BSF 104 via the Zn 114 interface to D-Proxy 118 and via the Zn '120 interface to BSF 104. The D-Proxy 118 function can be introduced as a separate network element or be part of any network element (NE) in a visited network that supports the Diameter proxy function (an example of this type of NE is the BSF of the network to which the visited NAF 102 or AAA server belongs).

[0019] In FIG. IA and IB, the principle of bootstrapping is that the UE 100 and bootstrapping function authorize each other, for example, using the AKA protocol and agree on a master shared secret. Then, the main shared secret is used to obtain one or more specific secrets of common network application functions that are used between the UE 100 and specific network application functions (NAFs). The NAF secret key is generated independently for each function of the web application. Upon completion of the bootstrapping task, UE 100 and the network application function can run a specific protocol in which message security will be based on keys generated during mutual authorization between the UE 100 and the bootstrapping server function. Thus, the keys can be used to authorize and protect integrity and to ensure confidentiality. The web application function may then acquire a specific common NAF secret resulting from the main shared secret established between the user equipment and the bootstrapping server function.

[0020] The Ub 112 communication interface supports bootstrapping authorization and key reconciliation protocol to ensure mutual authorization and key agreement between UE 100 and BSF 104. The protocol may be based, for example, on 3GPP AKA.

[0021] The Zh 116 interface allows BSF 104 to provide all required authorization information and subscriber profile information from HSS 106. The Ua 110 interface supports any application-specific protocol that is secured using a specific common NAF secret resulting from a main common secret between the EU 100 a BSF 104, based on the protocol provided by the Ub 112 interface. The Zn 114 interface is used by NAF 102 to obtain a specific common NAF secret that results from the main common secret agreed in the protocol supported on the Ub 112 interface with BSF 104. The Zn 114 interface can also be used to obtain information about a subscriber profile from BSF 104.

[0022] The message sent from BSF 104 to NAF 102 contains bootstrapping information. Bootstrapping information may include a transaction identifier, a specific NAF common secret, and optional subscriber profile information ("profnaf" or "any USS specified for NAF [any NAF specific USSs]"). The common specific NAF secret, designated as KsNAF, is established between UE 100 and BSF 104 and can be modified for specific use in communication between UE 100 and a specific NAF. Ks NAF results from Ks using the parameters specified in 3GPP TS 33.220 Annex B (Annex A). Fr is the main common secret, and Fr NAF is the specific common secret of NAF. The bootstrapping information sent to each NAF is thus unique for a given NAF, according to the specific common secrets of the NAF Account for such NAF.

[0023] A set of all user security settings GUSS includes a specific BSF information element and a set of all application-specific USS. A set of all user security settings (USS), i.e.GUSS, is stored in the HSS. In the case where the subscriber has multiple subscriptions, i.e. many ISIM or USIM applications on UICC, HSS will contain one or more GUSS that can be mapped to one or several identities, e.g. IMPI (IP Multimedia Private Identity) and IMSI (International Mobile Subscriber Identity).

[0024] The introduction of a new case for two specific common NAF secrets in GB AU, where one is used on UICC (KsintNAF) and the other on mobile equipment (Ks_ext_NAF). This case requires some "decision logic" regarding which key to use, ie Ks int NAF or Ks_ext_NAF. The introduction of new services to this kind of "logic" should be possible without reconfiguring the smart card mounted on the mobile terminal. If NAF supports more than one type of key, all types of security-level attacks should be prevented. This attack could be based on the fact that NAF would be deceived and would use a lower security key instead of requiring Ks int NAF.

[0025] According to an embodiment of the invention, a generic mechanism is provided for the application server that allows to find out which of the GAA (Generic Authentication Architecture) keys will allow easy integration of additional application servers by extending the existing USS (User Security Settings) standard. AVP (Attribute-Value-Pairs) are defined in 3GPP TS 29.109, Zn GAA interface of Bootstrapping-InfoRequest / Answer messages, attached here in the form of Annex C, the content of which has been introduced by reference, and additional new Diameter AVP are defined in 3GPP TS 29.229 , attached here as Annex D, the content of which has been introduced by reference.

[0026] The generic mechanism can be introduced in the form of an invariant value or by locally configuring the use of the key directly in the software in each NAF during configuration of the NAF (locally in the NAF), in the form of the invariant use of the key in the BSF (BSF instructs passing only the key to the NAF), providing

-8 additional fields in the user security settings (USS), stored in the Home Subscriber Server (HSS), which are sent to BSF and / or using AVP saved in BSF, which informs about key usage. If BSF will provide only key keys to NAF, NAF will not have information on the security quality communicated and the type of key it uses.

[0027] The 3GPP standard and existing User Security Settings (USS) can be extended and used to show which key to use. This would allow the user's home operator full and flexible control, especially in the case where the service is offered by a third party NAF and the service is settled by the home operator.

[0028] According to an embodiment of the invention, there are at least two possible embodiments. In a first embodiment of the invention, the USS may indicate the type of smart card or secure environment that the user has. In addition, the first embodiment provides information on whether the Universal SIM (USIM) card, the IMS SIM card (ISIM) supports GBA U or not. In the first embodiment, there may be a flagged field that indicates whether the card or secure environment supports GBA U.

[0029] In a second embodiment of the invention, the USS may include one or two flagged authorization fields that are transmitted in the USS of the existing 3GPP TS 29.109 specification, attached herein as Annex D, the content of which is incorporated herein by reference. In the first flagged field, if the field is present and informs about the use of a shared secret based on UICC (Ks int NAF) it is mandatory. The second flagged field may be an optional field in which, if the second flagged field is present, it informs about the use of a shared secret based on ME (Ks_ext_NAF or KsNAF) usage.

[0030] If the mobile subscriber is provided in the form of a home operator having a new subscriber identity module, the USS can be easily updated to require the safer KsintNAF key from now on. Both alternatives provide protection against attacks, i.e. the Ks_ext_NAF key is used instead of the more secure Ks int NAF.

[0031] FIG. 2 shows a device 150 providing a generic mechanism for a network application server, according to an embodiment of the invention. The device 150 includes a receiving unit 152 that receives requests from the user equipment to provide authorization information for the function of the network application. The device 150 further includes a determining unit 154 that specifies a generic authorization architecture key to integrate additional network application servers by extending the existing user security settings standard. The device 150 also includes a first delivery unit 156 that provides authorization information for the functions of the network application.

[0032] FIG. 3 illustrates a method providing a generic mechanism for a network application server according to an embodiment of the invention. During step 200, the method receives a request from the user equipment to provide authorization information for the network application function. During step 210, the method specifies a generic authorization architecture key to integrate additional network application servers by extending the existing user security standard. During step 220, authorization information for the functions of the web application is provided. According to an embodiment of the invention, the USS may inform what type of smart card the user has or what type (i.e. Ks_ext_NAF or Ks int NAF) of the common secret should be used. During step 230, the method determines whether the Universal SIM (USIM) card, IMS SIM (ISIM) card or other secure environment supports GBA U or not. In the first embodiment, there may be a flagged field that indicates whether the card or secure environment supports GBA U.

[0033] FIG. 4 illustrates a method providing a generic mechanism for a network application server according to another embodiment of the invention. During step 300, the method receives a request from the user equipment to provide authorization information for the function of the network application. During step 310, the method specifies a generic authorization architecture key to integrate additional web application servers by extending the existing user security standard. During step 320, authorization information for the functions of the web application is provided. According to an embodiment of the invention, the USS may inform what kind of smart card or secure environment the user has or what kind of shared secret should be used. During step 330, the method determines whether the USS contains one or two flagged fields carried in the Authorization header of the existing 3GPP TS 29.109 specification, attached here as Annex C. In the first flagged field, if the field is present and informs about the use of a shared secret based on UICC (Ks int NAF) it is mandatory. The second flagged field may be an optional field in which, if the second flagged field is present, it indicates the use of a shared secret based on ME (Ks_ext_NAF or KsNAF).

[0034] If a new application server has been configured in the operator's network, it does not need to know which key to use for a given user or whether the user will be equipped with a new SIM card in the near future. NAF will then obtain the necessary information on key selection from BSF.

[0035] According to an embodiment of the invention, a new AVP may be used to show the type of key used. For example, the new AVP may indicate whether the generated key is Ks int NAF or another type of key. The new AVP will inform you if the card or secure environment supports GB AU or, alternatively, which key to use. Depending on the flag, NAF may use a shared secret key based on UICC (Ks int NAF). That is, AVP informs that the card or secure environment supports GB AU or AVP only informs about the use

-10KsintNAF. NAF will then require the use of this key instead of another one with a lower security level.

[0036] For a network server in a secure environment, for example for a smart card, the client may be located on the UICC (Integrated Circuit Card) of the UMTS (Universal Mobile Telecommunications System) system, and the application will also be in a secure environment. It will usually be a Java application, XML application, C ++ application, Perl application or Visual Basic application or other similar applications. Then, UICC can also act as an application server offering a network service towards other entities, one of which can be located in another trusted domain, e.g. the second secure phone area, and Ks int NAF can be used to secure communication between network service entities. NAIC-based NAF will assume the role of WSP (Web Service Provider) as outlined in ID-WSF (Liberty Alliance Web Service Framework Specification) http.7 /<a href="http://www.proiectliberty.org/resources/specifications.php%c2%b7_UICC_mo%c5%bce_dzia%c5%82a%c4%87_jako_dostawcaus%c5%82ug_sieciowych_zgodnych_z_Liberty_Alliance_dostarczaj%c4%85c_jednostce_%c5%bc%c4%85daj%c4%85cej_(tj._klientaus%c5%82ugi_sieciowej)_wa%c5%bcne_informacje,_kt%c3%b3re_mog%c4%85_by%c4%87_autoryzowane/zabezpieczone_zapo%c5%9brednictwem_Ks_int_NAF._Pozosta%c5%82e_klucze_bazuj%c4%85ce_na_GAA_wykorzysta%c4%87_mo%c5%bcna_ponadtow_ramach_us%c5%82ug_sieciowych_dla_identyfikacji_i_bezpiecze%c5%84stwa_komunikacji._Ponadto,TS24.109_3GPP_okre%c5%9bla_interfejs_bootstrapping_(Ub)_i_interfejs_funkcji_aplikacji_sieciowej(Ua),_za%c5%82%c4%85czone_tutaj_w_postaci_Za%c5%82%c4%85cznika_E,_kt%c3%b3rego_tre%c5%9b%c4%87_wprowadzona_jest_przezodniesienie._TS29.109_3GPP_okre%c5%9bla_interfejsy_Zh_i_Zn_w_oparciu_o_protok%c3%b3%c5%82_Diameter(diameter_protocol),_za%c5%82%c4%85czone_tutaj_w_postaci_Za%c5%82%c4%85cznika_F,_kt%c3%b3rego_tre%c5%9b%c4%87_wprowadzona_jestprzez_odniesienie">www.proiectliberty.org/resources/specifications.php· UICC can act as a Liberty Alliance compliant network service provider by providing the requesting entity (i.e. network service client) with important information that can be authorized / secured via Ks int NAF. Other GAA-based keys can also be used as part of network services for communication identification and security. In addition, TS24.109 3GPP defines the bootstrapping interface (Ub) and the web application function interface (Ua), attached here as Annex E, the content of which is incorporated by reference. TS29.109 3GPP defines Zh and Zn interfaces based on the Diameter (diameter protocol) protocol, attached here as Annex F, the content of which is entered by reference</a>.

[0037] The invention provides the subscriber's home operator with full control over the level of security used. Updating user security settings in case the user has a new UICC can be centralized in the Home Service Server (HSS) and you will not need to update all NAF separately. Decision logic can be located on HSS or BSF controlled by the user. In addition, security attacks are not possible for new applications.

[0038] The above description relates to a specific embodiment of the invention. It will be appreciated that modifications of the described embodiments are possible using some or all of the functions.

Prepared and verified

Grażyna Palka Patent Attorney