A method for protecting confidentiality and / or integrity of a data communication channel of a slice

Abstract

The invention proposes a method 800 for protecting the confidentiality and / or the integrity of a data communication channel of a slice established between a user equipment 100 comprising a secure element 110 and a VPN server 117 cooperating with an authentication, authorization and accounting server AAA-S 104. The method comprises generating 802, at the secure element 110 and at the AAA-S 104, at least one secret key identical at the secure element 110 and at the AAA-S 104 after an EAP authentication procedure is completed between the mobile equipment 111 and the AAA-S 104. The method further comprises establishing 804 an interface between a user plane function (UPF) 115 of the HPLMN 300 and a UPF 114 of the VPLMN and exchanging 806 messages between the user equipment 100 cooperating with a VPN client 112 and the VPN server 117 by using a VPN using the at least one secret key.

Description

Technical Field

[0001] This invention relates to telecommunications, and more particularly to 5G network slicing. Background Technology

[0002] 5G network slicing is a network architecture that provides a way to partition a network to offer independent logical networks in terms of physical network resources and functionality. This can help operators (MNOs) provide differentiated services and quickly deploy new use cases.

[0003] Operators can use network slicing to logically allocate physical resources across one or more slices, where each slice can have different quality of service (QoS) and other performance characteristics, as well as configurations and policies to meet various use cases and possible service level agreements (SLAs).

[0004] For example, slices supporting mobile broadband users can require high data rates and traffic volumes, slices supporting Internet of Things (IoT) devices can optimize for high-density devices and power consumption, and slices supporting autonomous driving can provide high-reliability and low-latency communication.

[0005] Currently, 3GPP only defines slice authentication (see, for example, "5G; 5G Systems; Network Slice Specific Authentication and Authorization (NSSAA) Services; Phase 3 (3GPP TS 29.526 Revision 16.2.0, Version 16)").

[0006] Figure 1 This is an excerpt from the European Telecommunications Standards Institute (ETSI) standard TS 133 501 V16.3.0 (2020-08) entitled "5G; Security architecture and procedures for 5G systems (3GPP TS 33.501 revision 16.3.0 version 16)," which shows Figure 16.3-1 describing the "network slice-specific authentication and authorization process."

[0007] The diagram shows five entities: User Equipment (UE) 100, which consists of security elements (such as Universal Integrated Circuit Card (UICC)) that cooperate with Mobile Equipment (ME), AMF (Access and Mobility Management Function) 101, NSSAAF (Network Slice Specific Authentication and Authorization Function) 102, AAA-P (Authentication, Authorization and Accounting Agent) 103, and AAA-S (Authentication, Authorization and Accounting Server) 104.

[0008] exist Figure 1In this process, the following steps are performed (according to the above standard): At step (1), for single network slice selection assistance information (S-NSSAI) that requires network slice specific authentication and authorization, AMF 101 may trigger the start of the network slice specific authentication and authorization process based on changes in subscription information or triggered by AAA-S 104.

[0009] For example, if network slice-specific authentication and authorization is triggered as a result of the registration process, AMF 101 can determine, based on the UE 100 context in AMF 101, that for some or all S-NSSAIs undergoing network slice-specific authentication and authorization, UE 100 has already been authenticated after the registration process on the first access. Based on the result (e.g., success / failure) of the previously registered network slice-specific authentication and authorization process, AMF 101 can determine, based on network policy, whether to skip network slice-specific authentication and authorization for these S-NSSAIs during registration on the second access. If the network slice-specific authentication and authorization procedure corresponds to a re-authentication and re-authorization procedure triggered by UE100 re-authenticating and re-authorizing one or more S-NSSAIs due to AAA server-triggered re-authentication and re-authorization as described in Section 4.2.9.2 of TS 23.502, or a re-authentication and re-authorization procedure triggered by AMF 101 based on operator policy or subscription changes, and if the S-NSSAIs requiring network slice-specific authentication and authorization are included in the allowed NSSAIs for each access type, then AMF101 selects the access type to be used to perform the network slice-specific authentication and authorization procedure based on network policy.

[0010] At step 2, AMF 101 may request from UE 100 a user ID (interchangeably referred to as "EAPID") for authentication using the Extensible Authentication Protocol (EAP) for S-NSSAI in the Non-Access Stratum Mobility Management (NAS-MM) transport message that includes S-NSSAI.

[0011] At step 3, UE 100 provides the EAP ID for S-NSSAI along with S-NSSAI in the NAS-MM transmission message toward AMF 101.

[0012] At step 4, AMF 101 sends the EAP ID to NSSAAF 102, which provides an interface with AAA, in an NSSAAF 102_NSSAA_Authenticate request. This request may include the EAP ID response, the General Public Subscription Identifier (GPSI), and S-NSSAI.

[0013] At step 5, if AAA-P 103 exists (e.g., when AAA-S 104 belongs to a third party and the operator deploys an agent to that third party), NSSAAF 102 forwards the EAP ID response message to AAA-P 103. Otherwise, i.e., when AAA-P does not exist, according to ETSI 3GPP TS 33.501 revision 16.3.0 version 16 189 ETSI TS 133 501 V16.3.0 (2020-08), NSSAAF 102 forwards the message directly to AAA-S 104. NSSAAF 102 routes to AAA-S 104 based on S-NSSAI. NSSAAF 102 / AAA-P 103 forwards the EAP identity message along with S-NSSAI and GPSI to AAA-S 104. The AAA-S 104 stores the GPSI to create an association with the EAP ID in the EAP ID response message, allowing the AAA-S 104 to later use the EAP ID to revoke authorization or trigger re-authentication. The AAA-S 104 uses the EAP-ID and S-NSSAI to identify which UE 100 requested the slice authorization.

[0014] In steps 6-11, EAP messages are exchanged with UE 100. These steps may be performed once or multiple times.

[0015] At step 12, EAP authentication is completed. The EAP success / failure message, along with GPSI and S-NSSAI, is delivered to NSSAAF 102 / AAA-P 103.

[0016] At step 13, NSSAAF 102 sends an NSSAAF 102_NSSAA_Authenticate response to AMF 101. The authentication response may include EAP-success / failure messages, S-NSSAI, and GPSI.

[0017] At step 14, AMF 101 sends a NAS-MM transmission message to UE 100. The NAS-MM transmission message may include an EAP-success / failure message.

[0018] At step 15, based on the result of slice-specific authentication (EAP - success / failure), if it is necessary to deliver a new allowed NSSAI or a new rejected NSSAI to UE 100, or if it is necessary to reassign AMF 101, AMF 101 initiates a UE 100 configuration update procedure for each access type, as described in Clause 4.2.4.2 of TS 23.502.

[0019] However, this standardized solution offers no security, especially for private network use cases:

[0020] For businesses, security and privacy are two mandatory considerations when choosing a private network;

[0021] - In the field of aircraft, for example, LAS (Landing Assist Sensors) secure communication must be deployed to ensure the privacy and security of communication (commands) between the cockpit and control tower; and

[0022] In the military domain, several tactical isolation zones (bubble) (e.g., IOPS-isolated E-UTRAN operations for public safety) use their own security systems within the isolation zone but cannot communicate outside of it (e.g., to headquarters or another isolation zone). In the event of a breach of the isolation zone, previous communications to headquarters or another isolation zone can be decrypted (stored and decrypted later). To avoid this risk, communications outside the isolation zone must be protected with a key unknown to the isolation zone's core network (CN).

[0023] Therefore, it is desirable to provide a solution for providing end-to-end protection (encryption and / or integrity) between user equipment (UE) and endpoints, including security elements such as USIM (Universal SIM), UICC (Universal Integrated Circuit Card), eUlCC (Embedded UICC), or iUlCC (Integrated UICC)).

[0024] International Patent Application Publication No. WO2022067654A1 describes an apparatus, method, and system for key-based authentication for mobile edge computing networks.

[0025] International Patent Application Publication No. WO2022262975A1 describes a method for achieving end-to-end security of communication sessions between user equipment and a gateway. Summary of the Invention

[0026] The proposed invention offers a solution to this problem.

[0027] More specifically, this invention proposes a method for protecting the confidentiality and / or integrity of a slice of data communication channel established between a user equipment (UE) and a VPN (Virtual Private Network) server. The UE includes a secure element that cooperates with the mobile equipment, and the VPN server cooperates with an Authentication, Authorization, and Accounting (AAA-S) server. The UE roams through a Visited Public Land Mobile Network (VPLMN) and connects to a Home Public Land Mobile Network (HPLMN) via the VPLMN. The method includes: after completing an EAP authentication process between the mobile equipment and the AAA-S, generating at least one secret key identical at both the secure element and the AAA-S. The method also includes establishing an interface between the HPLMN's User Plane Function (UPF) and the VPLMN's UPF. Furthermore, after establishing the interface between the HPLMN's UPF and the VPLMN's UPF, the method includes exchanging messages between the UE and the VPN server, which cooperate with a VPN client, using the at least one secret key to protect the confidentiality and / or integrity of the data communication channel, via a VPN.

[0028] According to some example implementations, the session key (SK) is derived from the master key (MK). Slice_enc This is used to generate secret keys for confidentiality purposes.

[0029] According to some example implementations, the session key (SK) is derived from the master key (MK). Slice_int This is used to generate a secret key for integrity purposes.

[0030] According to some example implementations, the data communication channel is in the user plane.

[0031] According to some example implementations, multiple parameters that allow for the establishment of protections in terms of confidentiality and / or integrity are pre-configured in the user equipment (100) or security element, or configured by the UDM (Unified Data Management). The UDM sends multiple parameters to the user equipment or security element.

[0032] According to some example implementations, the method also includes configuring at least one of the following:

[0033] -The interface between UPF and VPN, and

[0034] - The interface between the base station (gNB) and the UPF of the VPLMN.

[0035] According to some example implementations, the method also includes configuring the radio interface between the ME and the gNB. Attached Figure Description

[0036] The invention will be better understood by reading the following description of preferred embodiments of the invention as non-exhaustive examples, wherein the accompanying drawings illustrate:

[0037] - Figure 1 This is an excerpt from ETSI standard TS 133 501 V16.3.0 (2020-08) entitled "5G; Security architecture and procedures for 5G systems (3GPP TS 33.501 revision 16.3.0 version 16)," showing a diagram (16.3-1) describing "network slice-specific authentication and authorization processes."

[0038] - Figure 2 Based on Figure 1 A signal flow diagram of the method according to the present invention;

[0039] - Figure 3 It is according to the invention for use in Figure 2 Signal flow diagram of the method for generating a shared secret between ME and AAA-S;

[0040] - Figure 4 This is a signal flow diagram of the method according to the invention, which illustrates an example of configuring safety parameters in mobile equipment from a UDM; and

[0041] - Figure 5 It is a method for protecting the confidentiality and / or integrity of data communication channels sliced ​​between user equipment and virtual private networks.

[0042] The invention will be better understood by reading the following description of these figures. Detailed Implementation

[0043] The term "network slice-specific authentication and authorization" refers to the process in 5G networks where a user's access to a specific network slice is verified and authorized based on the user's identity and the requirements of that slice. This process is typically managed by a dedicated function within the network infrastructure known as the "Network Slice-Specific Authentication and Authorization Function (NSSAAF)".

[0044] The term “private network” as used in this disclosure is equivalent to a non-public network (or NPN in the 3GPP specification), or sometimes referred to as a mobile private network (MPN).

[0045] exist Figure 2 In the middle, it indicates that it is related to Figure 1 The same entities as the entities (100 to 104).

[0046] Figure 2 Steps 2 and 3 in the middle Figure 1Steps 2 and 3 illustrated herein are identical (i.e., AMF 101 requests a user ID for EAP authentication for S-NSSAI from UE 100, and UE 100 provides the EAP ID for Single Network Slice Selection Assistance Information (S-NSSAI) along with S-NSSAI to AMF 101 via ME 111). S-NSSAI is used to support network slicing to uniquely identify network slices.

[0047] In this diagram, the complete system is represented by assuming that UE 100 does not connect directly to its home public land mobile network (HPLMN) 300, but instead connects to its home public land mobile network (VPLMN) 200. The configuration here is that UE 100 wants to connect to a private network managed by Enterprise 400 via VPLMN 200.

[0048] The entity represented in this diagram is:

[0049] - In VPLMN 200:

[0050] - UICC 110, which works in conjunction with ME 111, both constitute Figure 1 UE 100;

[0051] - VPN 112 connected to or integrated into ME 111;

[0052] -Base station (gNB) 113;

[0053] - Figure 1 AMF 101;

[0054] - User plane functionality (UPF) 114;

[0055] -In HPLM N300:

[0056] - Figure 1 NSSAAF 102;

[0057] - Figure 1 AAA-P 103;

[0058] -UPF 115;

[0059] -Data Network (DN) 116;

[0060] -In Enterprise 400:

[0061] -connected to Figure 1 VPN 117 of AAA-S 104.

[0062] gNB refers to a base station or next-generation node B in the 5G mobile communication standard. It acts as the radio access network for 5G devices, responsible for sending and receiving data between 5G devices and the core network.

[0063] As will be described in detail below, the present invention includes adding VPN servers 112 and 117 between UE 100 and AAA-S 104 in order to protect all communication between UE 100 and AAA-S 104.

[0064] The method of the present invention provides a method for protecting the confidentiality or integrity (or both) of data communication channels established between slices of data:

[0065] - User equipment 100, which includes a security element 110 that cooperates with mobile equipment 111, and

[0066] -VPN (Virtual Private Network) server 117, which works in conjunction with authentication, authorization and accounting server (AAA-S) 104.

[0067] This invention specifically relates to the protection of the user plane (U-Plane), which is the process of sending and receiving user data, which is the main signal used for communication.

[0068] The data communication channel is preferably located in the user plane.

[0069] After performing steps 2 and 3 as described above, at the UICC 110 and AAA-S 104 levels, the secret key can be generated or known in advance at step 500.

[0070] At step 501, the secret key is sent from UICC 110 to ME 111.

[0071] Then, standardized switching is performed between ME 111 and VPN 117:

[0072] -Establish a radio interface between ME 111 and gNB 113.

[0073] - Establish an N3 5G interface between gNB 113 and UPF 114.

[0074] -Establish an N9 5G interface between UPF 114 and UPF 115.

[0075] - Establish an N6 5G interface between UPF 115 and VPN 117.

[0076] The 5G N3 interface performs the role of transmitting user data from the RAN to the user plane, enabling the creation of both low-latency and high-latency services. It replaces the S1-U interface of the 4G Evolved Packet Core (EPC) and is key to supporting the new Control and User Plane Separation (CUPS) architecture with distributed user data processing. Testing and validating these interfaces is essential, but it presents a challenge.

[0077] The N9 interface is a special feature of the 5G core UPF, which means that two UPFs can be deployed in series and connected via an interface called N9.

[0078] In 4G networks, the SGi interface (defined by 3GPP) serves as the interface between the EPC and the public IP network. Importantly, services delivered through this interface can be identified by the user's IP address, enabling user and service differentiation. Therefore, the SGi interface can be considered a service gateway and a key enabler for new services, especially when combined with features such as deep packet inspection and policy-based service selection.

[0079] The N6 interface plays the same role in 5G networks, providing connectivity between the UPF and any other external (or internal) network or service platform, such as the Internet, public cloud, or private cloud.

[0080] Once the protocol is established, the present invention proposes to protect (steps 502 and 503) all data exchanged between ME111 and VPN server 117 via a secure VPN link 504.

[0081] Master key generation and session key export can be performed in ME 111 or UICC 110.

[0082] ME 111 utilizes the secret key SK for confidentiality. Slice_enc and / or the secret key SK used for integrity Slice_int To protect the data to be transmitted to AAA-S 104, and AAA-S 104 uses the same secret key SK Slice_enc and / or SK Slice_int To protect the data to be transmitted to ME 111.

[0083] Therefore, the confidentiality and integrity of communication are ensured within the scope of the user plane communication channel sliced ​​between the two entities.

[0084] This solution is based on at least one shared secret key (SK). Slice_enc and / or SK Slice_int ).

[0085] Furthermore, the present invention also proposes generating a derived session key (SK) at security element 110 (or at ME 111) and at AAA-S 104. Slice_enc Key and / or SK Slice_int The same secret key is generated, and this session key is derived from the master key MK and the parameter list. The parameter list may include one or more of the following:

[0086] • Tags, such as "Slice-Enc";

[0087] • Session ID;

[0088] •EAP-ID;

[0089] • Key type (e.g., encryption, integrity);

[0090] • Key size; and

[0091] • Algorithm type.

[0092] The master key MK is either the master session key (MSK) or the extended master session key (EMSK) as defined in RFC 3748 of EAP (Extensible Authentication Protocol).

[0093] This is Figure 3 The information is publicly available, including:

[0094] - At step 600, a master key is generated at AAA-S 104 and secure element 110;

[0095] - At step 601, AAA-S 104 and secure element 110 derive the secret key SK. Slice_enc and / or SK Slice_int ;

[0096] -Step 501 and Figure 2 The steps are the same as in step 501;

[0097] - In steps 502 to 504, a VPN link is established between VPNs 112 and 117.

[0098] Alternatively, the master session key (MSK) can be derived from the master key (MK), and then the SK can be derived from the master session key (MSK). Slice_enc and SK Slice_int .

[0099] VPNs 112 and 117 can be native VPNs. This has the following advantages: encryption of the sliced ​​user plane communication channels is "plug and play": no upper-layer application needs to be installed.

[0100] Furthermore, credentials can be securely protected outside the service network, and user credentials can be remotely managed by a credential manager.

[0101] Figure 4 This is a signal flow diagram used to configure security parameters in the ME from the UDM (Unified Data Management).

[0102] AMF is in the service network (VPLMN or HPLMN).

[0103] At step 700, the AMF sends a request to the UDM to obtain subscriber information based on TS 29.503, TS 23.501 and TS 23.502 (in the command Nudm_SubscriberDataManagement).

[0104] As described above, these parameters can be one of the following:

[0105] • Tags, such as "Slice-Enc";

[0106] • Session ID;

[0107] •EAP-ID;

[0108] • Key type (e.g., encryption, integrity);

[0109] • Key size; and

[0110] • Algorithm type.

[0111] These parameters can be pre-configured in the UE (UICC 110 or ME 111) or configured by the UDM 120.

[0112] At step 701, the UDM responds with security parameters such as key length, parameters, encryption algorithm, and required security encryption, for the ME to use to protect the data exchanged between VPNs 112 and 117.

[0113] At step 702, these security parameters are sent to ME 111 (UE parameter update) in a NAS-MM message, which then sends them to either user equipment 100 or security element 110.

[0114] Figure 5An example of a method 800 for protecting the confidentiality and / or integrity of a slice of data communication channel established between user equipment 100 and VPN (Virtual Private Network) server 117 is illustrated. User equipment 100 includes a security element 110 cooperating with mobile equipment 111, and VPN server 117 cooperating with authentication, authorization, and accounting server (AAA-S) 104. User equipment 100 roams through a visited public land mobile network (VPLMN) 200 and connects to a home public land mobile network (HPLMN) 300 via VPLMN 200.

[0115] At step 802, after the EAP authentication process is completed between mobile equipment 111 and AAA-S 104, at least one secret key identical to that at security element 110 and AAA-S 104 is generated. This is achieved by deriving the session key (SK) derived from the master key (MK). Slice_enc A secret key is generated for confidentiality by deriving the session key (SK) from the master key (MK). Slice_int This is used to generate a secret key for integrity purposes.

[0116] At step 804, an interface is established between the user plane function (UPF) 115 of HPLMN 300 and the UPF 114 of VPLMN.

[0117] At step 806, after establishing an interface between UPF 115 and UPF 114, messages are exchanged between user equipment 100 cooperating with VPN client 112 and VPN server 117 by using a VPN that uses at least one secret key to protect the confidentiality and / or integrity of the data communication channel.

[0118] In some implementations, the data communication channel is in the user plane.

[0119] In some implementations, multiple parameters that allow for protection in terms of confidentiality and / or integrity are pre-configured in the user equipment or security element 110, or configured by the UDM 120. The UDM 120 transmits the multiple parameters to the user equipment 100 or the security element 110.

[0120] In some implementations, the method further includes configuring at least one of the following:

[0121] -The interface between UPF 115 and VPN 117, and

[0122] - The interface between base station (gNB) 113 and UPF 114 of VPLMN 200.

[0123] In some implementations, the method also includes configuring the radio interface between the ME 111 and the gNB 113.

[0124] Various embodiments of the present invention may include one or more computer programs stored or otherwise embodied on a computer-readable medium, wherein the computer programs are configured to cause a processor or computer to perform one or more operations. A computer-readable medium storing, embodying, or encoding a computer program or similar language may be embodied as a tangible data storage device storing one or more software programs configured to cause a processor or computer to perform one or more operations. Such operations may be any steps or actions, as described herein. In some embodiments, any type of non-transitory computer-readable medium may be used to store and provide a computer with a computer.

Claims

1. A method (800) for protecting the confidentiality and / or integrity of a data communication channel established between slices of: - User equipment (100), the user equipment including a security element (110) cooperating with mobile equipment (111), and -VPN Virtual Private Network Server (117), which collaborates with Authentication, Authorization and Accounting Server AAA-S (104), The user equipment (100) roams through the visited public land mobile network (200) VPLMN and connects to the home public land mobile network (300) HPLMN through the VPLMN (200). The method (800) includes: - After the Extensible Authentication Protocol (EAP) authentication process is completed between the mobile equipment (111) and the AAA-S (104), at least one secret key identical to that at the security element (110) and the AAA-S (104) is generated (802) at the security element (110) and the AAA-S (104); - Establish an interface (804) between the user plane function (115) UPF of the HPLMN (300) and the UPF (114) of the VPLMN (200); as well as - After the interface is established, the VPN exchanges (806) messages between the user equipment (100) cooperating with the VPN client (112) and the VPN server (117) by using the VPN, and the VPN uses the at least one secret key to protect the confidentiality and / or integrity of the data communication channel.

2. The method (800) according to claim 1, wherein the session key (SK) is derived from the master key (MK). Slice_enc The secret key is generated for confidentiality purposes.

3. The method (800) according to claim 1, wherein the session key (SK) is derived from the master key (MK). Slice_int The secret key is generated for integrity purposes.

4. The method (800) according to any one of claims 1 to 3, wherein the data communication channel is in the user plane.

5. The method (800) according to any one of claims 1 to 4, wherein a plurality of parameters that allow the establishment of the protection in terms of confidentiality and / or integrity are pre-configured in the user equipment (100) or the security element (110), or configured by a UDM (120), wherein the UDM (120) transmits the plurality of parameters to the user equipment (100) or the security element (110).

6. The method (800) according to any one of claims 1 to 5, wherein the method (800) further comprises: Configure at least one of the following: -The interface between the UPF (115) and the VPN (117), and - The interface between the base station (113) gNB and the UPF (114) of the VPLMN (200).

7. The method (800) of claim 6, wherein the method (800) further comprises configuring a radio interface between the ME (111) and the gNB (113).

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