Method for authenticating a subscriber in a local network, home authentication center and UICC application
By exporting the local key in the home authentication center and performing local authentication in the UICC application, security and synchronization problems in 3GPP authentication are solved, and secure authentication and high security are achieved within the local E-UTRAN network.
Patent Information
- Application Number
- CN202210632531.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Priority Date
- 2015-09-04
- Filing Date
- 2016-07-05
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2036-07-05
AI Technical Summary
In the 3GPP authentication, the existing technology relies on the shared key between the home HSS and the local network, and there are security issues and synchronization issues. The attacker may obtain physical access to the local HSS, resulting in authentication failure and security risks.
An authentication scheme is proposed that does not require instant communication between local and home networks. By storing subscriber keys in the home authentication center, derives local keys, and performing local authentication in UICC applications, using keys specific to each local network. Ensure high safety and control.
It realizes secure authentication within the local E-UTRAN network, avoids the sharing of keys between multiple local networks, improves security and control, and ensures high reliability and uniqueness of authentication.
Smart Images
Figure CN114866518B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method of authenticating a subscriber within a local network without requiring online communication between the local network and the subscriber's home network.
[0002] A local network is defined as a network that is different from the home network in which the subscriber is registered.
[0003] The present invention also relates to an authentication center and UICC application of a Home Subscriber Server (HSS) hosted by a home operator. Background Art
[0004] 3GPP addresses new scenarios where an operator's subscribers should be authenticated within the local E-UTRAN network (4G) without communication with the home network. This scenario is for business use or for public safety, especially when the macro network is not available.
[0005] Operators are interested in maintaining control of the authentication of their subscribers within a local network. Subscribers should not be allowed to be authenticated within a local network that is deployed without an agreement with the subscriber's home operator.
[0006] Solutions that rely on one unique key shared between the Home HSS, the UICC application and all local networks to authenticate a subscriber within any local network may have security issues in situations where the Local HSS will be hosted in an environment that is less secure than the Home HSS. In such a scenario, it may happen that an attacker may have physical access to the Local HSS and retrieve the unique key used to authenticate the subscriber. As a result, all other local networks that use the same key to authenticate the subscriber will be known.
[0007] In the case of 3GPP authentication, there may also be synchronization issues with the use of a sequence number (SQN) mechanism. Using the same SQN within different local networks that are not connected for synchronization may in some scenarios end up with desynchronization of the UICC. Authentication may then fail and additional procedures may be necessary.
[0008] Therefore, further alternative and advantageous solutions are desirable in the art. Summary of the invention
[0009] The present invention aims to propose a novel scheme for authentication in which no on-the-fly communication between the local and home networks takes place.
[0010] The present invention is defined in its broadest sense as a method comprising the following preliminary steps, directed to a Home Authentication Centre (AuC) of a Home Subscriber Server (HSS) hosted in a home network:
[0011] - a subscriber key (Kmacro) for each subscriber is stored in the Home Authentication Centre, which has a key derivation function (KDF) and is specific to the authentication of that subscriber within any local network agreed with the Home Operator,
[0012] – derive local keys from the subscriber key, one for each local network the subscriber is authorized to access,
[0013] - provisioning each local network the subscriber is authorized to access with its own local key,
[0014] – provisioning subscriber keys and key derivation functions (KDF) to subscriber’s UICC applications,
[0015] – provisioning the subscriber’s UICC application with an algorithm to perform local authentication,
[0016] The method further comprises the following steps: when authentication is required in a given local network, for the UICC application:
[0017] – receiving a network identifier,
[0018] – derive local keys in the subscriber’s UICC application using the network identifier of the local network, the key derivation function and the subscriber’s keys,
[0019] - Use the derived local key in the algorithm to perform local authentication in the local network.
[0020] The present invention relies on the generation of local keys both in the operator's network and in the user equipment of the operator's subscribers to perform AKA authentication of the subscriber within the local E-UTRAN network.
[0021] The home network sends the local key to any local E-UTRAN network where the subscriber is authorized to be present and can be locally authenticated thanks to AKA authentication.One local key is specific to only one local network.
[0022] The present invention allows operators to continue to use the AKA algorithm to authenticate their subscribers within the local network. This thus allows the home operator to maintain control within the local network. Authentication only occurs if the local authentication center AuC and the user equipment are provisioned with keys provided by the home operator. The use of local keys specific to only one local network provides a high level of security. This feature is important in situations where the local authentication center AuC would be more vulnerable than the home authentication center AuC, which is included in the one of the local HSS. If an attacker has access to one local authentication center AuC, the retrieved local keys cannot be used for authentication within other local networks.
[0023] The present invention also has the advantage of allowing local authentication based on symmetric keys. This further ensures that UICC-based authentication will occur when the subscriber is within the local network. Because AKA-based authentication should be hosted in the UICC, credential-based solutions can be hosted in the terminal part of the user equipment.
[0024] The authentication method used in the local network (ie AKA authentication using AUTN, RAND) may be a standard method and does not require modification in the local network or in the UICC.
[0025] The UICC will only contain an additional file or dedicated application storing the new subscriber key and all derived local keys for all local networks.
[0026] An associated OTA service is advantageously implemented to update the list of authorized local networks.
[0027] According to an advantageous feature, the method comprises as a preliminary step the steps of: for the authentication center, supplying the UICC application of the subscriber with a list of identifiers of local networks to which the subscriber is authorized to access, and, when authentication is required in a given local network, for the UICC application, a step of checking the presence of the identifier of the local network in the list.
[0028] With this feature it is necessary for the UICC application to also contain a list of authorized local networks in which the subscriber is to be authorized to exist.
[0029] According to an advantageous implementation, once the local key has been derived by the UICC application, the method further comprises a step of storing the local key for the local network and a step of checking the existence of the stored local key against an identifier of the local network.
[0030] This feature avoids repeated key derivation every time the UICC enters the local network.
[0031] According to a specific implementation, the authentication process uses a serial number mechanism, which further includes the following steps: for the authentication center and for the UICC application, while deriving local keys, a local serial number array is associated with each derived local key.
[0032] Such serial number arrays are typically associated with some standard authentication process. The present invention is fully compatible with such standards.
[0033] The invention also relates to an authentication centre of a home subscriber server hosted in a home network, said authentication centre storing subscriber keys for each subscriber application, said subscriber keys being specific to the authentication of the subscriber within any local network agreed with the operator of the home network, said authentication centre having a key derivation function to derive local keys from the subscriber keys, one for each local network to which the subscriber is authorized to access, said authentication centre having provisioning resources to provision each local network to which the subscriber is authorized to access with its own local keys, and provisioning the subscriber's UICC with its own subscriber keys, a key derivation function (KDF) and an algorithm to perform local authentication.
[0034] Such an authentication center enables the implementation of the present invention on the home network side.
[0035] The present invention relates at least to a UICC application provided with a subscriber key dedicated for authentication of a subscriber within any local network having an agreement with a home network, a key derivation function (KDF) and an algorithm for performing local authentication, the UICC application being further adapted to receive a network identifier from the local network and to use the network identifier, the key derivation function and the subscriber key to derive a local key in the UICC application of the subscriber, the UICC application being further adapted to use the derived local key in the algorithm to perform local authentication in the local network.
[0036] Such a UICC application enables the implementation of the present invention on the user equipment side.
[0037] To the accomplishment of the foregoing and related ends, the one or more embodiments comprise the features hereinafter fully described and particularly pointed out in the claims. BRIEF DESCRIPTION OF THE DRAWINGS
[0038] The following description and drawings set forth certain illustrative aspects in detail and indicate only a few of the various ways in which the principles of the embodiments may be employed. Other advantages and novel features will become apparent from the following detailed description when considered in conjunction with the accompanying drawings, and the disclosed embodiments are intended to include all such aspects and their equivalents.
[0039] · Figure 1 represents an environment in which the present invention is implemented;
[0040] · Figure 2 Functional diagram showing the exchanges between entities of the method according to the invention. DETAILED DESCRIPTION
[0041] For a more complete understanding of the present invention, the present invention will now be described in detail with reference to the accompanying drawings. The detailed description will illustrate and describe the contents that are considered as the preferred embodiments of the present invention. It should be understood that various modifications and changes in form or details can be easily made without departing from the spirit of the present invention. It is therefore intended that the present invention may not be limited to the exact form and details shown and described herein, nor to anything less than the entirety of the present invention disclosed herein and as claimed below. The same elements have been assigned the same reference numerals in different figures. For clarity, only those elements and steps that have been shown in the accompanying drawings and will be described that are useful for understanding the present invention.
[0042] Figure 1 Schematically shown is an environment comprising a home network HN and two local networks LN1 and LN2. Each of them has a corresponding Home Subscriber Server HSS, LHSS1 and LHSS2 and an Authentication Centre HAuC, LAuCl, LAuC2. The HSS is accessible to base stations in its corresponding local network.
[0043] It is to be noted here that the user equipment UE comprises a UICC with a UICC application and a mobile equipment ME, wherein the UICC application has an IMSIi associated to the user's subscription. IMSIi is an identifier of a subscriber for a specific UICC application. If there are several UICC applications in the UICC, each UICC application can have a dedicated IMSI. There is nothing to prevent having several UICCs in the UE.
[0044] The user equipment UEa and UEb have IMSI1 in the UICC application and IMSI2 in the UICC application respectively, the IMSIi originating from the home network HN. It is also noted here that the reference sign "IMSI" is used to refer to the identity of the subscriber according to UMTS terminology. Any other kind of identity is contemplated, such as IMPI (IMS) and others.
[0045] User equipment UEa and UEb are prone to enter into communication with a base station of a local network LNj, for example in a situation where UEa and UEb can no longer communicate with the normal network. In such a situation, the subscriber needs to be authenticated within the local network LNj without any contact with the home operator.
[0046] For this purpose, the invention proposes that the authentication center HAuC of the home network HN initially stores a subscriber key SMKi for each subscriber i, and possibly a random value RANDi to be optionally used in a derivation function. The subscriber key SMKi is dedicated to the authentication of the subscriber associated to the IMSIi in the UICC application within any local network agreed with the home operator HN.
[0047] According to the present invention, the authentication center AuC has a key derivation function to derive a local key from the subscriber key SMK. Thus, the local key LKi of each local network LNj that has reached an agreement with the home operator is obtained. LNj Then the local key LKi LNj Sent to the HSS of the local network LNj concerned, such as Figure 2 As shown above for the local network LN1. Send a local key LKi for each subscriber i that has access and is authorized to enter the local network LNj. The local authentication center LAuCj stores all these local keys LKi LNj .
[0048] In case of 3GPP AKA authentication, the AuC of the home HSS sends to the local HSS LHSSj an array of serial numbers (SQN) associated to each local key LK. It stores all these keys, one per subscriber, and in case of 3GPP AKA authentication, the local authentication center LAuC also contains an array of serial numbers (SQN) associated to each local key LK.
[0049] Then at the UICC of the user equipment UEa, in the UICC application with IMSI1, the subscriber key SMKi, the derivation function KDF, the algorithm for performing local authentication (e.g. 3GPPAKA authentication (Milenage)), and possibly the random value RANDi are provisioned. This step concludes the preliminary step PrS of the invention which necessitates a dedicated communication with the UICC of the subscriber IMSIi when it is in the domain of the home network.
[0050] Additionally, the UICC application contains a list of local networks LNj in which subscriber i is authorized. The operator of the home network may update this list of authorized local networks when a UE with a UICC containing a UICC application with IMSIi has been or is again in the territory of the home network.
[0051] Then, when the local network LN1 initiates a connection with the local network ( Figure 2 During mutual authentication of the UICC application with IMSI1 of the user equipment UEa in LN1 in the local network, the user equipment UEa receives the local network identifier Id(LN1), and the user equipment UEa provides the local network identifier Id(LN1) to the UICC application with IMSI1, such as the USIM.
[0052] When the identifier Id(LN1) is not in the list of authorized networks, authentication fails. When the identifier Id(LN1) is in the list of authorized networks, the corresponding local network key SMK1 is triggered LN1Selection and activation of the derivation function KDF to obtain the local key LK1 for the identified local network LN1 LN1 .
[0053] The invention can be implemented in such a way that the local HSS LHSS1 keeps the local key in memory if it has already been derived for the user equipment. In this case, when the network is listed, the UICC application then checks whether the local key was calculated before. In such a case, the derivation is not performed again and the stored local key associated to the network in question is used.
[0054] Otherwise, derivation is in fact triggered. Each local key is specific to one local network per subscriber. The derivation of the local key is linked to the identity IMSI1 of the subscriber and the identity Id(LN1) of the local network, thus: LK1 LN1 =KDF(SMK1,"local-aka",RAND1,IMSI1,Id(LN1)).
[0055] The obtained local keys may be stored depending on the implementation.In case of AKA based authentication, as specified by 3GPP, an array of sequence numbers (SQN) is associated to each local key LK.
[0056] Then, using the security authentication Aut(LK1 of LHSS1 of the local network LN1 LN1 ) using the local key LK1 LN1 . Preferably AKA authentication is used.
[0057] According to the present invention, the UICC application stores the following triples:
[0058] Id(LNj), LK1 LNj , SQNj, for as many j as there are networks of interest.
[0059] In the above detailed description, reference is made to the accompanying drawings which show by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Therefore, the above detailed description is not to be construed in a limiting sense, and the scope of the invention is limited only by the appended claims, appropriately interpreted, together with the full scope of equivalents to which the claims are granted.
Claims
1. A method of authenticating a subscriber (IMSIi) within a local network (LNj) comprising the following preliminary steps, directed to a Home Authentication Centre (HAuC) of a Home Subscriber Server (HSS) hosted in a Home Network (HN): – a Subscriber Key (SMKi) for each subscriber (IMSIi) is stored in the Home Authentication Centre (HAuC) which has a Key Derivation Function (KDF) and is specific to the authentication of that subscriber (IMSIi) within any Local Network (LNj) agreed with the Home Operator (HN), – Derivation of the local key (LKi) from the subscriber key (SMKi) LNj ), there is a local key (LKi) for each local network (LNj) that the subscriber (IMSIi) is authorized to access. LNj ), – Provision each local network (LNj) that the subscriber (IMSIi) is authorized to access with its own local key (LKi LNj ), – provisioning the subscriber key (SMKi) and key derivation function (KDF) to the UICC application of the subscriber (IMSIi), – Provisioning algorithms to perform local authentication for the UICC application of the subscriber (IMSIi), The method further comprises the following steps: When authentication is required in a given local network (LNj), for the UICC application: – receiving network identifier (Id(LNj)), – Use the network identifier (Id(LNj)) of the local network (LNj), the key derivation function (KDF) and the subscriber key (SMKi) to derive the local key (LKi) in the UICC application of the subscriber (IMSIi). LNj ), – Use the derived local key (LKi) in the algorithm LNj ) to perform local authentication in the local network (LNj), There is no instant communication between the local network and the home network during the authentication.
2. Method according to claim 1, comprising as preliminary step the steps of: for the Home Authentication Centre (HAuC), provisioning for the UICC application of the subscriber (IMSIi) a list of identifiers (Id(LNj)) of local networks which the subscriber (IMSIi) is authorized to access, and, when authentication is required in a given local network (LNj), for the UICC application, checking for the presence of the identifier (Id(LNj)) of the local network in the list.
3. The method according to claim 1, wherein: Once the local key (LKi LNj ) is derived by the UICC application, the method further comprising storing a local key (LKi) for the local network (LNj) LNj ) and checking the stored local key (LKi) against the identifier of the local network (Id(LNj)) LNj ) existence step.
4. The method according to claim 1, wherein: The authentication process uses a sequence number mechanism, which also includes the following steps: for the Home Authentication Center (HAuC) and for the UICC application, before deriving the local key (LKi LNj ), while associating the local sequence number array to each derived local key (LKi LNj ).
5. A Home Authentication Center (HAuC) of a Home Subscriber Server (HSS) hosted in a Home Network (HN), the Home Authentication Center (HAuC) storing a Subscriber Key (SMKi) for each Subscriber application, the Subscriber Key (SMKi) being dedicated for authentication of a Subscriber (IMSIi) within any Local Network (LNj) agreed with the operator of the Home Network, the Home Authentication Center (HAuC) having a Key Derivation Function (KDF) to derive a Local Key (LKi) from the Subscriber Key (SMKi) LNj ), one for each local network (LNj) that the subscriber (IMSIi) is authorized to access, the Home Authentication Center (HAuC) has provisioning resources to provision each local network (LNj) that the subscriber (IMSIi) is authorized to access with its own local key (LKi LNj ), and supplies the UICC application of the subscriber (IMSIi) with its own subscriber key (SMKi), key derivation function (KDF) and algorithms to perform local authentication, wherein the home authentication center (HAuC) is configured to derive a local key for a specific local network using the key derivation function (KDF) and the subscriber key (SMKi), wherein the local key derived by the authentication for the specific local network matches a local key derived by the UICC application for the specific network using the key derivation function (KDF) and the subscriber key (SMKi), There is no instant communication between the local network and the home network during the authentication.
6. UICC application equipment comprising a UICC application provided with a subscriber key (SMKi) dedicated for authentication of a subscriber (IMSIi) within any local network (LNj) having an agreement with the home network (HN), a key derivation function (KDF) and an algorithm for performing local authentication, The UICC application is further adapted to receive a network identifier (Id(LNj)) from a local network (LNj) and use the network identifier (Id(LNj)), a key derivation function (KDF) and a subscriber key (SMKi) to derive a local key (LKi) in the UICC application of the subscriber (IMSIi). LNj ), the UICC application is further adapted to use the derived local key (LKi LNj ) to perform local authentication in a local network (LNj), wherein the local key (LKi) derived for the local network (LNj) is applied by the UICC LNj) matches a local key derived by authentication using the key derivation function (KDF) and the subscriber key (SMKi), wherein no immediate communication occurs between the local network and the home network during the authentication.