Centralized key generation for distributed nas in 6g

Abstract

Embodiments of the present disclosure design centralized key generation for distributed NAS (DNAS) in 6G. According to aspects of the present disclosure, a method includes establishing an anchor key in a user equipment (UE) and a network node supporting a security key management function (SKMF) after a successful primary authentication procedure; receiving, by the UE from the SKMF, a non-access stratum (NAS) message having a NAS module identifier (ID) of a network function (NF), a key set identifier (KSI), and scope or coverage information; and deriving, by the UE, a single parent key, wherein the scope information is used as an input parameter to derive a NAS integrity key and a NAS encryption key.

Description

Technical Field

[0001] The various example implementations generally involve apparatus, methods, and computer program products that support centralized key generation. Background Technology

[0002] Wireless networks offer significant advantages to user mobility. The ability to maintain connectivity while on the move not only benefits the user but also contributes to greater efficiency and productivity across society. As expectations for connection reliability, data speed, and low power consumption become more demanding, technologies for wireless networks must keep pace. Consequently, improvements to wireless networking technologies are receiving continuous attention. Summary of the Invention

[0003] According to various aspects of this disclosure, a method includes: establishing an anchor key in a user equipment (UE) after a successful master authentication process; receiving a non-access stratum (NAS) message from a network node supporting Security Key Management Function (SKMF), the NAS message having a NAS module identifier (ID) of the network function (NF), a key set identifier (KSI), and range or coverage information; and deriving a single parent key by the UE, wherein the range information is used as an input parameter to derive a NAS integrity key and a NAS encryption key.

[0004] On one hand, deriving a single parent key may include the UE deriving a single parent key based on the received range information and KSI.

[0005] On one hand, deriving a single parent key can include: the UE deriving a single parent key based on KSI without receiving NF range information; and the UE deriving the NAS integrity key and NAS encryption key based on the generated single parent key and range information.

[0006] On the one hand, NAS messages can be protected for integrity using NAS integrity keys.

[0007] According to various aspects of the present invention, a user equipment (UE) includes: at least one processor; and at least one memory storing instructions, which, when executed by the at least one processor, cause the UE to perform at least one of the methods described above.

[0008] According to various aspects of this disclosure, a processor-readable medium stores instructions that, when executed by at least one processor of a user equipment (UE), cause the UE to perform at least one of the methods described above.

[0009] According to various aspects of this disclosure, a method includes: establishing an anchor key in a Security Key Management Function (SKMF) and a User Equipment (UE) after a successful master authentication process; receiving a NAS key request including range information from a Network Function (NF) by the SKMF; and generating a single parent key by the SKMF, wherein the range information is used as an input parameter to derive a NAS integrity key and a NAS encryption key.

[0010] On one hand, generating a single parent key may include generating a single parent key by SKMF based on the received range information.

[0011] On one hand, deriving a single parent key can include: generating a single parent key by SKMF based on KSI without receiving NF range information; and generating a NAS integrity key and a NAS encryption key by SKMF based on the generated NAS parent key and range information.

[0012] In one aspect, the method may also include receiving a NAS key request with range information and a security algorithm ID from the NF by the SKMF.

[0013] In one aspect, the method may further include: verifying by the SKMF whether the NF is permitted to receive the requested range of NAS keys; and, upon successful verification, assigning a key set identifier (KSI) by the SKMF.

[0014] In one aspect, the method may also include: generating a single parent key by SKMF based on KSI.

[0015] In one aspect, the method may further include: generating a NAS integrity key and a NAS encryption key by SKMF based on a single parent key; or, if the range information is not used to generate a single parent key, generating a NAS integrity key and a NAS encryption key by SKMF using the range information as an input parameter.

[0016] In one aspect, the method may also include: SKMF sending the NAS integrity key, the NAS encryption key, and the KSI to NF.

[0017] According to various aspects of this disclosure, a network device includes at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the network device to perform at least one of the methods described above.

[0018] According to various aspects of this disclosure, a processor-readable medium stores instructions that, when executed by at least one processor of a network device, cause the network device to perform at least the method according to any one of the foregoing methods.

[0019] The independent claims provide the subject matter for several aspects. Additional aspects are defined in the dependent claims. Attached Figure Description

[0020] Some example implementation schemes will now be described with reference to the accompanying drawings.

[0021] Figure 1 This is a schematic diagram of an example embodiment of wireless networking between a network system and a user equipment (UE) according to one aspect of this disclosure; Figure 2 This is a schematic diagram of an example component of a network system according to one aspect of this disclosure; Figure 3 This is a schematic diagram illustrating an example of authorization and key generation for each type of network function (NF) according to one aspect of this disclosure; Figure 4 This is a schematic diagram of a request for a parent key generated according to one aspect of this disclosure; Figure 5 This is a schematic diagram of centralized NAS key generation for all NFs according to one aspect of this disclosure; Figure 6 This is a schematic diagram of NAS key generation for requesting multiple parent keys according to one aspect of this disclosure; Figure 7 This is a schematic diagram illustrating an example of NAS key generation based on one of the aspects explained in this disclosure, which requests a single parent key. Figure 8 This is a block diagram of an example component of a UE or network device according to one aspect of this disclosure. Detailed Implementation

[0022] This disclosure relates to centralized key generation.

[0023] In the following description, certain specific details are set forth in order to provide a thorough understanding of the disclosed aspects. However, those skilled in the art will recognize that the aspects can be practiced without one or more of these specific details or using other methods, components, materials, etc. In other instances, well-known structures associated with transmitters, receivers, or transceivers have not been shown or described in detail to avoid unnecessarily obscuring the description of the aspects.

[0024] Throughout this specification, the reference to "an aspect" or "aspect" means that a particular feature, structure, or characteristic described in connection with that aspect is included in at least one aspect. Therefore, the phrases "in an aspect" or "in one respect" appearing in various places throughout this specification do not necessarily refer to the same aspect. Furthermore, a particular feature, structure, or characteristic may be combined in one or more aspects in any suitable manner.

[0025] The embodiments described in this disclosure can be implemented in wireless networking devices, such as, but not limited to, devices utilizing Global Microwave Access Interoperability (WiMAX), Global System for Mobile Communications (GSM, 2G), GSM EDGE Radio Access Network (GERAN), General Packet Radio Service (GRPS), Universal Mobile Telecommunications System based on Basic Wideband Code Division Multiple Access (W-CDMA) (UMTS, 3G), High-Speed ​​Packet Access (HSPA), Long Term Evolution (LTE), Advanced LTE, Enhanced LTE (eLTE), 5G New Radio (5GNR), 5G Advanced, 6G (and above), and 802.11ax (Wi-Fi 6), and other wireless networking systems. The term "eLTE" here refers to LTE evolution connected to a 5G core. LTE is also referred to as Evolved UMTS Terrestrial Radio Access (EUTRA) or Evolved UMTS Terrestrial Radio Access Network (EUTRAN).

[0026] This disclosure may use the term "serving network device" to refer to a network node or network device (or part thereof) serving a UE. As used herein, the terms "transmitting toward," "sending to," "receiving from," and "cooperating with" (and variations thereof) include communication that may or may not involve communication through one or more intermediate devices or nodes. The term "acquiring" (and variations thereof) includes acquiring in a first instance or re-acquiring after a first instance. The term "connection" may refer to a physical connection or a logical connection.

[0027] This disclosure uses 6G as an example of a wireless network, and may use smartphones and / or extended reality headsets as examples of UEs. It is intended and should be understood that such examples are merely illustrative, and this disclosure can be applied to other wireless networks and user equipment.

[0028] Figure 1This is a diagram illustrating an example of wireless networking between network system 100 and user equipment (UE) 150. Network system 100 may include one or more network nodes 120, one or more servers 110, and / or one or more network devices 130 (e.g., test devices). Network node 120 will be described in more detail below. As used herein, the term "network apparatus" may refer to any component of network system 100, such as server 110, network node 120, network device 130, any of the foregoing components, and / or any other component of network system 100. Examples of network apparatus include, but are not limited to, apparatuses for implementing various aspects of 5G NR. This disclosure describes implementations related to 5G NR and 6G, as well as implementations relating to aspects defined by the 3rd Generation Partnership Project (3GPP). However, it is contemplated that implementations related to other wireless network technologies are included within the scope of this disclosure.

[0029] The following description provides further details of examples of network nodes. In a 6G network, a gNodeB (also known as a gNB) may include, for example, a node that provides user plane and control plane protocol termination toward the UE and is connected to the 6G core (6GC) via an interface, such as according to Section 3.2 of 3GPP TS 38.300 V 16.6.0 (2021-06), which is incorporated herein by reference.

[0030] gNB supports various protocol layers, such as Layer 1 (L1) - the physical layer, Layer 2 (L2) and Layer 3 (L3).

[0031] NR's Layer 2 (L2) is divided into the following sublayers: Media Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), and Service Data Adaptation Protocol (SDAP), among which, for example: The physical layer provides a transmission channel to the MAC sublayer. The oMAC sublayer provides logical channels to the RLC sublayer; The oRLC sublayer provides RLC channels to the PDCP sublayer; The oPDCP sublayer provides radio bearers to the SDAP sublayer; The oSDAP sublayer provides 6G Quality of Service (QoS) streams; The control channels include the Broadcast Control Channel (BCCH) and the Physical Control Channel (PCCH).

[0032] Layer 3 (L3) includes, for example, Radio Resource Control (RRC) according to Section 6 of 3GPP TS 38.300 V 16.6.0 (2021-06), which is incorporated herein by reference.

[0033] The gNB Central Unit (gNB-CU) includes, for example, logical nodes that host, the gNB's Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP), and Packet Data Convergence Protocol (PDCP) protocols, or the gNB's RRC and PDCP protocols, and controls the operation of one or more gNB Distributed Units (gNB-DUs). The gNB-CU terminates the F1 interface connected to the gNB-DU. The gNB-CU may also be referred to herein as a CU, Central Unit, Centralized Unit, or Control Unit.

[0034] A gNB Distributed Unit (gNB-DU) comprises, for example, a logical node that hosts the Radio Link Control (RLC), Media Access Control (MAC), and Physical (PHY) layers of a gNB or en-gNB, and its operation is partially controlled by the gNB-CU. One gNB-DU supports one or more cells. A cell is supported by only one gNB-DU. The gNB-DU terminates the F1 interface connected to the gNB-CU. The gNB-DU may also be referred to herein as a DU or Distributed Unit.

[0035] The gNB-CU-Control Plane (gNB-CU-CP) includes, for example, logical nodes that host the RRC and control plane portion of the PDCP protocol for the gNB-CU, such as for the en-gNB or gNB. The gNB-CU-CP terminates the E1 interface connected to the gNB-CU-User Plane (gNB-CU-UP) and the F1-C interface connected to the gNB-DU.

[0036] The gNB-CU-User Plane (gNB-CU-UP) includes, for example, logical nodes that host the user plane portion of the gNB-CU for the en-gNB, as well as the user plane portions of the PDCP and SDAP protocols for the gNB-CU. The gNB-CU-UP terminates the E1 interface connected to the gNB-CU-CP and the F1-U interface connected to the gNB-DU, for example, according to Section 3.1 of 3GPP TS 38.401 V 16.6.0 (2021-07), which is incorporated herein by reference.

[0037] As used herein, the term "network node" may refer to any one or any combination of gNB, gNB-CU, gNB-DU, gNB-CU-CP, or gNB-CU-UP.

[0038] RAN (Radio Access Network) nodes or network nodes (such as, for example, gNB, gNB-CU, or gNB-DU, or portions thereof) can be implemented using, for example, means having at least one processor and / or at least one memory having processor-readable instructions (“programs”) configured to support and / or provide and / or process CU and / or DU-related functionalities and / or features, and / or at least one protocol (sub-) layer (e.g., layer 2 and / or layer 3) of the RAN (Radio Access Network). Different functional divisions between central and distributed units are possible. The following will combine... Figure 4 Examples describing such devices and components.

[0039] The g NB-CU and g NB-DU portions can, for example, be co-located or physically separated. The g NB-DU can even be further divided into, for example, two parts, one including processing equipment and the other including an antenna. The Central Unit (CU) can also be referred to as a Baseband Unit / Radio Equipment Controller / Cloud-RAN / Virtual-RAN (BBU / REC / C-RAN / V-RAN), Open-RAN (O-RAN), or a portion thereof. The Distributed Unit (DU) can also be referred to as a Remote Radio Headend / Remote Radio Unit / Radio Equipment / Radio Unit (RRH / RRU / RE / RU), or a portion thereof. In the various example embodiments of this disclosure, a network node supporting at least one of the Central Unit functions or Layer 3 protocols of a radio access network can be, for example, a g NB-CU. Similarly, a network node supporting at least one of the Distributed Unit functions or Layer 2 protocols of a radio access network can be, for example, a g NB-DU.

[0040] A g NB-CU can support one or more g NB-DUs. A g NB-DU can support one or more cells, and therefore can support the serving cell for a user equipment (UE), or candidate cells for handover, dual connectivity and / or carrier aggregation and other procedures.

[0041] User equipment (UE) 150 may be or include wireless or mobile devices, devices having a radio interface for interacting with a RAN (Radio Access Network), smartphones, in-vehicle devices, IoT devices, or M2M devices, and other types of user equipment. Such a UE 150 may include: at least one processor; and at least one memory including program code; wherein the at least one memory and the computer program code are configured, together with the at least one processor, to cause the device to perform at least certain operations, such as, for example, an RRC connection to the RAN. Figure 4Examples of components of the UE are described below. In an implementation, UE 150 may be configured to generate messages to be transmitted to the RAN via radio (e.g., including a cell ID) (e.g., to reach and communicate with the serving cell). In an implementation, UE 150 may generate, transmit, and receive RRC messages containing one or more RRC PDUs (Packet Data Units). Those skilled in the art will understand the RRC protocol and other processes that the UE may perform.

[0042] Continue to refer to Figure 1 In an example of a 6G network, network system 100 provides one or more cells that define the coverage area of ​​network system 100. As described above, network system 100 may include a gNB of a 6G network, or may include any other means configured to control radio communications and manage radio resources within the cells. As used herein, the term "resource" may refer to radio resources such as resource blocks (RBs), physical resource blocks (PRBs), radio frames, subframes, time slots, subbands, frequency regions, subcarriers, beams, etc. In an implementation, network node 120 may be referred to as a base station.

[0043] Figure 1 Examples are provided, and only network system 100 and UE 150 are illustrated. Those skilled in the art will understand that network system 100 includes... Figure 1 Components not shown in the diagram, and it will be understood that other user equipment can communicate with network system 100.

[0044] Figure 2 yes Figure 1 A block diagram of example components of network system 100. A 6G network can be described as an example of network system 100, and the aspects described below should also be applicable to other types of network systems. The network system can be configured according to... Figure 1 The signals and connections shown operate to enable UE 150 to communicate with network system 100 via radio access network (RAN) 225. Additionally, the network system can be divided into user plane components and functions and control plane components and functions, as shown and described herein. Unless otherwise stated, the terms “component,” “function,” and “service” are used interchangeably herein and can refer to instructions executed by and implemented by one or more processors.

[0045] The following describes example functionality of the components. This example functionality is merely illustrative, and it should be understood that additional operations and functions can be performed by the components described herein. Furthermore, connections between components can be virtual connections over service interfaces, enabling any component to communicate with any other component. In this way, any component can act as a service "producer" for any other component acting as a service "consumer," providing services for network functions.

[0046] For example, a core network 210 is described in the control plane of the network system. The core network 210 may include an Authentication Server Function (AUSF) 211, an Access and Mobility Management Function (AMF) 212, and a Session Management Function (SMF) 213. The core network 210 may also include a Network Slice Selection Function (NSSF) 214, a Network Open Function (NEF) 215, a Network Repository Function (NRF) 216, and a Unified Data Management Function (UDM) 217, which may include a Unified Data Repository (UDR) 224.

[0047] Additional components and functions of the core network 210 may include application functions (AF) 218, policy control functions (PCF) 219, network data analysis functions (NWDAF) 220, analytical data repository functions (ADRF) 221, management data analysis functions (MDAF) 222, and operation and management functions (OAM) 223.

[0048] The user plane includes UE 150, Radio Access Network (RAN) 225, User Plane Function (UPF) 226, and Data Network (DN) 227. RAN 225 may include a combination of Figure 1 The RAN 225 describes one or more components, such as one or more network nodes. However, the RAN 225 may not be limited to such components. The UPF 226 provides connectivity for data transmitted through the RAN 225. For example, the UPF 226 identifies services from service providers, internet access, and third-party services.

[0049] AMF 212 handles connectivity and mobility tasks. AUSF 211 receives authentication requests from AMF 212 and interacts with UDM 217 to authenticate and verify network responses to determine successful authentication. SMF 213 performs Packet Data Unit (PDU) session management and manages session context with UPF 226.

[0050] NSSF 214 can select a Network Slice Instance (NSI) and determine the allowed Network Slice Selection Assistance Information (NSSAI). This selection and determination are used to set up AMF 212 to provide services to UE 150. NEF 215 ensures third-party access to network services to create private network services. NRF 216 acts as a repository for storing network functions to allow functions to register and discover each other.

[0051] UDM 217 generates authentication vectors for use by AUSF 211 and AMF 212 and provides user identity processing. UDM 217 can connect to UDR 224, which stores data associated with authentication, applications, etc. AF 218 provides application services (e.g., streaming services) to users. PCF 219 provides policy control functions. For example, PCF 219 can assist in network slicing and mobility management, as well as provide Quality of Service (QoS) and accounting functions.

[0052] NWDAF 220 collects data (e.g., from UE 150 and network systems) to perform network analytics and provide insights into the capabilities that leverage analytics when providing services. ADRF 221 allows consumers to store, retrieve, and remove data and analytics. MDAF 222 provides additional data analytics services for network functions. OAM 223 provides provisioning and management processing capabilities to manage elements in or connected to the network (e.g., UE 150, network nodes, etc.).

[0053] Figure 2 This is merely an example of a component of a network system, and variations are expected within the scope of this disclosure. In implementations, the network system may include... Figure 2 Other components not shown. In an implementation, the network system may not include... Figure 2 Each component is shown. In the implementation, the components and connections can be used with... Figure 2 The connections shown are implemented using different connections. These and other implementations are considered to be within the scope of this disclosure.

[0054] This disclosure relates to centralized key generation.

[0055] This disclosure addresses a technical problem of potential threats, in which the NAS module of NF A establishes a secure NAS channel on behalf of NF B and the NAS module on the UE.

[0056] This threat can also be prevented if the MM NF (NF A) can ensure that NAS packets are routed between the correct endpoints. For example, if the LMF is sending a secure NAS channel request to a NAS module on the UE with the SMF's module ID, the MMNF can detect this and block the request. However, the MMNF can also be dishonest. Furthermore, if there is no trusted MM NF transport hub at all, there is no way to know that authorization can be made. Therefore, it is better if message forwarding and security are completely decoupled.

[0057] The disclosed system and method provide a technical solution for deriving secure keys for protecting messages between NAS modules on the UE and in the 6G core network. This is achieved by binding the derived security keys to the characteristics of the modules involved. In this way, impersonation attacks, i.e., allowing one NAS module to impersonate another NAS module, can be prevented.

[0058] Figure 3 This is a diagram illustrating example operations for centralized key generation. These operations are performed by... Figure 3 The components shown at the top perform the function, including the UE and one or more network devices (e.g., network nodes, gNBs) that perform the SKMF function. Such components can be, for example, combined with... Figure 1 and Figure 2 The same component described above or otherwise.

[0059] The UE is configured to run several NAS modules. The NAS modules in the UE securely exchange messages with corresponding NAS modules in the core network. The UE is able to derive and use security keys specific to the modules used to protect messages between the NAS modules on the UE and the modules in the core network. One or more NAS modules can operate in the core network. NAS modules are typically implemented through network functions (NFs). The Security Key Management Function (SKMF) is configured to derive security keys used to protect messages between the NAS modules in the core and on the UE, and to transmit these keys to the NAS modules in the core. Depending on the authorization method used in the core network, the network apparatus may also include a network repository function that can authorize NFs and issue access tokens to NFs; it contains the results of the authorization. It is conceivable that sending messages between the NAS modules on the UE and in the core may involve other nodes used for message transmission.

[0060] At Operation 301, the User Equipment (UE), Non-Access Stratum (NAS) module, Security Key Management Function (SKMF), and Home Network (HN) perform a successful authentication process between the UE and Unified Data Management (UDM), and make the anchor key in the SKMF and UE available.

[0061] At operation 302a, the NAS module sends a key request to the SKMF, which includes a requested range that is a summary of all characteristics that can be used to distinguish the two different NAS modules. The SKMF receives the key request from the NAS module.

[0062] At Operation 302b, SKMF verifies that the NAS module is permitted to obtain the NAS key within the requested scope. SKMF authorizes the request.

[0063] At operation 302c, SKMF uses a range as input for key derivation to generate the NAS parent key. Figure 4 6 and 7) At operation 303a, the SKMF sends the NAS module parent key to the NF that has the NAS module. The NF with the NAS module receives the NAS module parent key from the SKMF.

[0064] At Operation 303b, the NAS module uses the parent key to derive the NAS integrity and encryption keys and prepares the setup message, signing it with the NAS key. The NAS message (first NAS SMC) is protected for integrity only and is not encrypted. This means that the content of the NAS SMC message, along with several other parameters listed in Appendix D of TS 33.501, is passed to the NIA (New Radio (NR) Integrity Protection Algorithm), such as: count, key (NAS integrity key), direction, and bearer for generating the NAS-MAC. This ensures that a man-in-the-middle attack cannot modify the NAS SMC message itself, and that it cannot be altered / tampered with and / or repudiated.

[0065] In Operation 303c, the NAS module sends a NAS Security Mode Command (SMC) setting, including the module identifier and range, to the UE. The UE receives the NAS SMC setting, including the module identifier and range, from the NAS module.

[0066] In operation 303d, the UE calculates the NAS key and verifies the integrity of the SMC message. Specifically, the UE stores the NAS key module identifier and range.

[0067] For example, the NAS module parent key is sent from the SKMF to the requesting NF. If the range used by the SKMF for key derivation differs from the range requested by the NF, the response also includes the actual range. The NAS module uses the received parent key to derive the NAS integrity key and the NAS encryption key. It also prepares an SMC establishment message (SMC command) and applies integrity protection using the NAS integrity key. A NAS SMC message is sent to the UE, including the KSI, module ID (e.g., assigned by the SKMF), and range. The range sent in this message is the same as the range used by the SKMF for key derivation. When the UE receives this message, it calculates the NAS parent key in the same way as with the SKMF. That is, the range is used as an input parameter for the KDF. The UE further derives the NAS integrity and encryption keys and verifies the integrity protection of the message. After successful verification, the NAS key is stored along with the module ID and range.

[0068] At operation 304a, the NAS module prepares the NAS content and encrypts and signs the content using the NAS key.

[0069] At operation 304b, the NAS module sends a NAS message to the UE, including the module identifier and encrypted content. The UE receives the NAS message, including the module identifier and encrypted content, from the NAS module.

[0070] In Operation 304c, the UE retrieves the NAS key and range, decrypts and verifies the content, and checks whether the content is within the range limits.

[0071] For example, the NAS module prepares to encrypt and protect NAS content using a NAS key. A NAS downlink message is sent to the UE, including the module ID, range, and encrypted content. When the UE receives the message, it retrieves the stored NAS key and range from the received module ID. The NAS content is decrypted, and the integrity protection is verified. Before executing the message content, the UE checks whether the content is within the range limits. If the check fails, the UE does not execute the message, triggering an error condition.

[0072] Figure 3 The operations described are merely examples, and variations are expected within the scope of this disclosure. In implementations, the operations may include... Figure 3 Other operations not shown. In the implementation, operations may not include... Figure 3 Each operation is shown. In the implementation, the operation can be correlated with... Figure 3 The different sequences shown are implemented. These and other implementations are considered to be within the scope of this disclosure.

[0073] Now for reference Figure 4There is a graph showing an example of requesting parent key generation. Specifically, the Security Key Management Function (SMKF) uses the Key Derivation Function (KDF) to compute the parent key used for the request. The Subscription Permanent Identifier (SUPI) is a globally unique 5G subscription permanent identifier assigned to each subscriber in the 5G system. The SUPI is defined as a SUPI type, which can indicate IMSI, Network Specific Identifier (NSI), Global Line Identifier (GLI), or Global Cable Identifier (GCI); and depends on the value of the SUPI type: IMSI; Network Specific Identifier (NSI), in the form of Network Access Identifier (NAI); Global Cable Identifier (GCI), in the form of NAI; Global Line Identifier (GLI), in the form of NAI.

[0074] After a successful master authentication process in each serving network, the SKMF receives the anchor key KSKMF or Ka from the AUSF. The SKMF will never transfer KSKMF or Ka to an entity outside the SKMF. Once the KMM NF is exported, KSKMF or Ka should not be deleted (unlike in 5G). The ABBA parameter is provided to the UE from the SKMF and is applied as an input parameter for other parent keys of the KMM NF, KSM NF, or NF with NAS modules. To support a flexible set of security features, the ABBA parameter is defined as security features change. To ensure forward compatibility, the ABBA parameter is a variable-length parameter. The SKMF should set the ABBA parameter to 0x0000. The UE should use the ABBA parameter provided by the SKMF to compute each parent key for NFs with NAS modules. The range contains all the characteristics that describe the NAS module and can be used to distinguish NAS modules. This can be the NF type, NF instance ID, or module ID, but can also be additional parameters such as slice ID or other domain IDs. The final range parameter used as input to the KDF is a concatenation of different parts of the range. The domain ID will be anything used to divide the network into smaller parts (i.e., domains). Domains can be associated with, for example, geographical regions. Different instances of NF can be deployed in each of these domains.

[0075] An NF can be any NF with a NAS module, such as an SM NF, MM NF, or LM NF.

[0076] The range used as input to the KDF can, for example, be exactly the range provided by the NF and authorized by the SKMF, or it can include additional parameters assigned by the SKMF, such as the module ID. If the range used as input to the KDF differs from the range requested by the NF, the SKMF needs to include that range in its key response to the NF. The NF type identifies the type of network function (e.g., SM NF type, MM NF type, and / or LM NF type). Since the NF type may not be unique, it is possible to add a random number to make it unique along with the NF type.

[0077] NF instance identification is a globally unique identifier for a set of equivalent and interchangeable NFs from a given network that provides distribution, redundancy, and scalability.

[0078] Using the NF instance identifier as part of the scope is particularly useful when the UE needs to communicate with several NAS modules of the same type. Note that the NF instance ID used in the context in which the NAS key is derived is not necessarily the same as the NF instance ID used in different contexts. In this case, the network topology (e.g., the number and distribution of NFs in the network) can be masked from the UE.

[0079] The module ID is an identifier used on the UE and in the core to deliver NAS messages to the correct terminating NAS module. Implementations of this invention may differ slightly depending on the definition and allocation of the module ID. For example, if the module ID is a combination of other parameters (such as NF type or instance ID), these parameters are sufficient as input to the KDF, and the module ID can be omitted.

[0080] If the instance ID, module ID, or any other ID is assigned by SKMF, this value needs to be included in the response to the request for NF, unless the value is part of the scope in any case.

[0081] KSI_kp1, KSI_kp2, ..., KSI_kpN are key set identifiers used to identify the key set for each network function.

[0082] KSI_kp1 is the key set identifier of the parent key of network function NF#1.

[0083] KSI_kp2 is the key set identifier of the parent key of network function NF#2.

[0084] KSI_kp3 is the key set identifier of the parent key of network function NF#3.

[0085] … KSI_kpN is the key set identifier of the parent key of network function NF#N.

[0086] Now for reference Figure 5 This illustrates a graph example of centralized NAS key generation for all network functions (NFs).

[0087] At Operation 501, the User Equipment (UE), Non-Access Stratum (NAS) module, Security Key Management Function (SKMF), and Home Network (HN) perform a successful authentication process, making the anchor key in the SKMF and UE applicable. The Mobility Management (MM) NF has a parent key obtained from the SKMF.

[0088] For example, the authentication process between the UE / USIM and UDM is successful, and the anchor key is applicable in the SKMF / UE. The MM NF has a parent key obtained from the SKMF. In all respects, only the MM NF can be provided with a parent key (derived from the SKMF). In this way, the MM NF can derive additional gNB keys. For any gNB handover (HO), the MM NF parent key can be used.

[0089] Operation 502a is similar to Figure 3 Operation 302a, in addition to including additional parameters for calculating the final security key in the message sent from NF to SKMF, such as the algorithm identifier ( Figure 6 and 7 In operation 502a, the NAS module sends a request for a NAS key to the SKMF, which includes an algorithm identifier. The SKMF receives the request for a NAS key from the NAS module, which also includes an algorithm identifier.

[0090] At Operation 502b, SKMF verifies that the NAS module is allowed to obtain the NAS key within the requested range.

[0091] At operation 502c, SKMF uses the range as input to generate NAS integrity and encryption keys.

[0092] At operation 503a, SKMF sends the NAS module integrity and encryption key to the NAS module. The NAS module receives the NAS module integrity and encryption key from SKMF.

[0093] At operation 503b, the NAS module prepares to establish a message and sign it using the NAS key.

[0094] At operation 503c, the NAS module sends a NAS Security Mode Command (SMC) setting, including the module identifier and range, to the UE. The UE receives the NAS SMC setting, including the module identifier and range, from the NAS module.

[0095] In Operation 503d, the UE calculates the NAS key, verifies the integrity of the message, and stores the NAS key module identifier and range.

[0096] At Operation 504a, the NAS module uses the NAS key to prepare NAS content and encrypt and sign it.

[0097] At operation 504b, the NAS module sends a NAS message to the UE, including the module identifier and encrypted content. The UE receives the NAS message, including the module identifier and encrypted content, from the NAS module.

[0098] In Operation 504c, the UE retrieves the NAS key and range, decrypts and verifies the content, and checks whether the content is within the range limits.

[0099] At operation 505, the NAS module and SKMF perform a key refresh or switch (HO), where the parent key is unavailable and the NAS module needs to obtain the key from SKMF each time.

[0100] The operation is described below from the UE's perspective. From this perspective, one approach could include: after a successful master authentication process, establishing an anchor key between the user equipment (UE) and a network node supporting Security Key Management Function (SKMF). Figure 5 Operation 501); The UE receives from the SKMF a NAS message containing a Network Functions (NF) Non-Access Stratum (NAS) Module Identifier (ID), Key Set Identifier (KSI), and range or coverage information (e.g., Figure 5 Operation 503d); and the UE derives a single parent key, where range information is used as input parameters to derive the NAS integrity key and NAS encryption key (e.g., Figure 5 (Operation 504c).

[0101] The following description of the operation is from the perspective of the network device. From this perspective, one approach may include: establishing an anchor key (e.g., after a successful master authentication process) in the Security Key Management Function (SKMF) and the User Equipment (UE). Figure 5 Operation 501); The SKMF receives a NAS key request, including range information, from the Network Function (NF) (e.g., Figure 5 Operation 503d); and a single parent key generated by SKMF, where range information is used as input parameters to derive the NAS integrity key and the NAS encryption key (e.g., Figure 5 (Operation 504c).

[0102] Now for reference Figure 6 The diagram illustrates the generation of a NAS key using multiple parent keys linked to the requesting NF. In each respect, multiple parent keys can be generated by linking multiple parent keys to the requesting NF via a range parameter. The parent keys will never be shared with the target NF that requested them. Instead, the NAS key is generated and shared with the requesting NAS entity. This can be achieved... Figure 3 and 5 It is used in operations 302a and 502a.

[0103] Now for reference Figure 7 The diagram illustrates the generation of a NAS key linked to a requesting NF using a single parent key. In all aspects, a single parent key can be generated (specific to all NFs requesting the NAS key from the SKMF). The parent key is not shared by the NAS modules. Instead, the NAS keys (int and enc keys) are computed using NF-specific ranges and sent to the NAS module requesting the NF. This can be done... Figure 3 and 5 It is used in operations 302a and 502a.

[0104] Now for reference Figure 8 This diagram illustrates a block diagram of example components of a UE or network device. The device includes an electronic storage device 810, a processor 820, a memory 850, and a network interface 840. The various components can be communicatively coupled to each other. The processor 820 can be and may include any type of processor, such as a single-core central processing unit (CPU), a multi-core CPU, a microprocessor, a digital signal processor (DSP), a system-on-a-hip (SoC), or any other type of processor. The memory 850 can be a volatile type of memory, such as RAM, or a non-volatile type of memory, such as NAND flash memory. The memory 850 includes processor-readable instructions executable by the processor 820 to cause the device to perform various operations, including those mentioned herein, such as... Figure 3 The operation.

[0105] Electronic storage device 810 can be and includes any type of electronic storage device used for storing data, such as hard disk drives, solid-state drives, and / or optical disks, as well as other types of electronic storage devices. Electronic storage device 810 stores processor-readable instructions for causing the device to perform its operations, and stores data associated with such operations, such as data related to the 5G NR standard and other data. Network interface 840 enables wireless networking technologies, such as 5G NR and / or other wireless networking technologies.

[0106] Figure 8 The components shown are merely examples, and those skilled in the art will understand that the apparatus includes other components not shown, and may include multiples of any of the components shown. These and other embodiments are considered to be within the scope of this disclosure.

[0107] Other implementations of this disclosure include the following examples.

[0108] Example 1.1 A user equipment (UE) for communication includes: Components for establishing an anchor key in the user equipment (UE) after a successful master authentication process; and A component for receiving Non-Access Stratum (NAS) messages by the UE from a network node supporting Security Key Management Function (SKMF), the NAS messages having a Network Function (NF) NAS Module Identifier (ID), Key Set Identifier (KSI), and range or coverage information; and A component for deriving a single parent key from the UE, wherein the range information is used as an input parameter to derive the NAS integrity key and the NAS encryption key.

[0109] Example 1.2 According to the User Equipment (UE) described in Example 1.1, deriving a single parent key includes: A component for the UE to derive the single parent key based on the received range information and the KSI.

[0110] Example 1.3 According to the user equipment (UE) described in Example 1.1, deriving a single parent key includes: A component for deriving a single parent key by the UE based on the KSI without receiving range information of the NF; and A component for the UE to derive the NAS integrity key and the NAS encryption key based on a single generated parent key and the range information.

[0111] Example 1.4 A user equipment (UE) according to Example 1.1, wherein the NAS messages are protected for integrity using a NAS integrity key.

[0112] Example 1.7 A network device for communication, comprising: A component used to establish anchor keys in the Security Key Management Function (SKMF) and User Equipment (UE) after a successful master authentication process; and Components for receiving NAS key requests, including range information, from the Network Function (NF) by the SKMF; and A component used to generate a single parent key from the SKMF, wherein the range information is used as an input parameter to derive the NAS integrity key and the NAS encryption key.

[0113] Example 1.8 A network apparatus according to Example 1.7, wherein generating a single parent key includes: A component used by the SKMF to generate the single parent key based on the received range information.

[0114] Example 1.9 A network apparatus according to Example 1.7, wherein deriving a single parent key includes: A component for generating a single parent key by SKMF based on KSI without receiving NF range information; and A component used by the SKMF to generate the NAS integrity key and the NAS encryption key based on the generated NAS parent key and the range information.

[0115] Example 1.10 The network device according to Example 1.7 further includes: A component used by SKMF to receive NAS key requests from NF, which include range information and security algorithm ID.

[0116] Example 1.11 The network apparatus according to Example 1.7 further includes: The component used by SKMF to verify whether the NF is allowed to receive NAS keys for the requested range, and A component used by the SKMF to assign a Key Set Identifier (KSI) upon successful verification.

[0117] Example 1.12 The network device according to Example 1.7 further includes: A component used by the SKMF to generate the single parent key based on the KSI.

[0118] Example 1.13 The network apparatus according to Example 1.7 further includes: A component used by the SKMF to generate the NAS integrity key and the NAS encryption key based on a single generated parent key; or A component used by the SKMF to generate the NAS integrity key and the NAS encryption key by using the range information as input parameters when the range information is not used to generate the single parent key.

[0119] Example 1.14 The network apparatus according to Example 1.7 further includes: The component used by SKMF to send NAS integrity key and NAS encryption key, as well as KSI, to NF.

[0120] The embodiments and aspects disclosed herein are examples of this disclosure and may be embodied in various forms. For example, although some embodiments herein are described as separate embodiments, each embodiment herein may be combined with one or more other embodiments herein. The specific structural and functional details disclosed herein should not be construed as limiting, but rather serve as the basis for the claims and as a representative basis for teaching those skilled in the art to apply this disclosure differently with virtually any suitable detailed structure. Throughout the description of the drawings, the same reference numerals may refer to similar or identical elements.

[0121] The phrases “in one aspect,” “in all aspects,” “in all dimensions,” “in some aspects,” or “in other aspects” may each refer to one or more of the same or different aspects under this disclosure. The phrase “multiple” may refer to two or more.

[0122] The phrases “in the implementation scheme,” “in the implementation scheme,” “in various implementation schemes,” “in some implementation schemes,” or “in other implementation schemes” can each refer to one or more of the same or different implementation schemes according to this disclosure. The phrase “A or B” means “(A), (B), or (A and B)”, and the phrase “at least one of A, B, or C” means “(A); (B); (C); (A and B); (A and C); (B and C); or (A, B, and C)”. Any method, program, algorithm, or code described herein can be translated into or expressed in a programming language or computer program. As used herein, the terms "programming language" and "computer program" each include any language used to specify instructions to a computer, and include (but are not limited to) the following languages ​​and their derivatives: assembly language, Basic, batch files, BCPL, C, C++, Delphi, Fortran, Java, JavaScript, machine code, operating system command languages, Pascal, Perl, PL1, Python, scripting languages, Visual Basic, meta-languages ​​that specify their own programs, and all first-, second-, third-, fourth-, fifth-, and more generation computer languages. Databases and other data schemas, and any other meta-languages, are also included. There is no distinction between languages ​​that are interpreted, compiled, or use compilation and interpretation methods. There is no distinction between compiled and source versions of a program. Therefore, a reference to a program in which a programming language can exist in more than one state (such as source, compiled, object, or linked) is a reference to any and all such states. A reference to a program can encompass the actual instructions and / or the intent of those instructions.

[0123] While various aspects of this disclosure have been shown in the accompanying drawings, they are not intended to be limited thereto, as the scope of this disclosure is intended to be as broad as would be permitted in the art, and similarly, when reading the specification. Therefore, the above description should not be construed as restrictive, but merely as an example of particular aspects. Other modifications within the scope and spirit of the appended claims will be contemplated by those skilled in the art. Furthermore, various implementations of this disclosure can be described with reference to the following provisions, and their features can be combined in any reasonable manner.

[0124] Clause 1. A method for communication, comprising: establishing an anchor key in a user equipment (UE) after a successful master authentication process; receiving a non-access stratum (NAS) message from a network node supporting a security key management function (SKMF), the NAS message having a NAS module identifier (ID), a key set identifier (KSI), and range or coverage information of a network function (NF); and deriving a single parent key by the UE, wherein the range information is used as an input parameter to derive a NAS integrity key and a NAS encryption key.

[0125] Clause 2. The method according to Clause 1, wherein deriving a single parent key comprises: the UE deriving the single parent key based on the received range information and the KSI.

[0126] Clause 3. The method according to Clause 1, wherein deriving a single parent key comprises: deriving the single parent key by the UE based on the KSI without receiving the range information of the NF; and deriving the NAS integrity key and the NAS encryption key by the UE based on the generated single parent key and the range information.

[0127] Clause 4. The method described in Clause 1, wherein the NAS message is protected for integrity using a NAS integrity key.

[0128] Clause 5. A user equipment (UE) for communication, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the UE to perform at least one method according to any one of Clauses 1 to 4.

[0129] Clause 6. A processor-readable medium storing instructions that, when executed by at least one processor of a user equipment (UE), cause the UE to perform at least the method according to any one of Clauses 1 to 4.

[0130] Clause 7. A method for communication, comprising: establishing an anchor key in a Security Key Management Function (SKMF) and a User Equipment (UE) after a successful master authentication process; receiving a NAS key request including range information from a Network Function (NF) by the SKMF; and generating a single parent key by the SKMF, wherein the range information is used as input parameters to derive a NAS integrity key and a NAS encryption key.

[0131] Clause 8. The method according to Clause 7, wherein generating a single parent key comprises: generating the single parent key by the SKMF based on the received range information.

[0132] Clause 9. The method described in Clause 7, wherein deriving a single parent key includes: The SKMF generates the single parent key based on the key set identifier KSI without receiving the range information of the NF; and the SKMF generates the NAS integrity key and the NAS encryption key based on the generated NAS parent key and the range information.

[0133] Clause 10. The method according to Clause 7 further includes: the SKMF receiving a NAS key request having range information and a security algorithm ID from the NF.

[0134] Clause 11. The method according to Clause 9 further comprises: the SKMF verifying whether the NF is permitted to receive NAS keys for the requested range, and, upon successful verification, the SKMF allocating the KSI.

[0135] Clause 12. The method according to Clause 9 further includes: generating the single parent key by the SKMF based on the KSI.

[0136] Clause 13. The method according to Clause 9 further comprises: the SKMF generating the NAS integrity key and the NAS encryption key based on the generated single parent key; or, if the range information is not used to generate the single parent key, the SKMF generating the NAS integrity key and the NAS encryption key using the range information as an input parameter.

[0137] Clause 14. The method according to Clause 7 further includes: the SKMF sending the NAS integrity key, the NAS encryption key, and the KSI to the NF.

[0138] Clause 15. A network device comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the network device to perform at least one method according to any one of Clauses 6 to 13.

[0139] Clause 16. A processor-readable medium storing instructions that, when executed by at least one processor of a network device, cause the network device to perform at least the method according to any one of Clauses 6 to 13.

Claims

1. A method for communication, comprising: After a successful master authentication process, an anchor key is established in the user equipment (UE). The UE receives a non-access stratum NAS message from a network node that supports the security key management function SKMF. The NAS message contains the NAS module identifier ID of the network function NF, the key set identifier KSI, and range or coverage information. as well as A single parent key is derived from the UE, wherein the range information is used as an input parameter to derive the NAS integrity key and the NAS encryption key.

2. The method of claim 1, wherein deriving a single parent key comprises: The UE derives the single parent key based on the received range information and the KSI.

3. The method of claim 1, wherein deriving a single parent key comprises: The UE derives the single parent key based on the KSI without receiving the range information of the NF; as well as The UE derives the NAS integrity key and the NAS encryption key based on the generated single parent key and the range information.

4. The method of claim 1, wherein the NAS message is protected for integrity using a NAS integrity key.

5. A user equipment (UE) for communication, comprising: At least one processor; as well as At least one memory storing instructions that, when executed by the at least one processor, cause the UE to perform at least the method according to any one of claims 1 to 4.

6. A processor-readable medium storing instructions that, when executed by at least one processor of a user equipment (UE), cause the UE to perform at least the method according to any one of claims 1 to 4.

7. A method for communication, comprising: Following a successful master authentication process, an anchor key is established in the Security Key Management Function (SKMF) and the User Equipment (UE). The SKMF receives a NAS key request, including range information, from the network function NF. as well as A single parent key is generated from the SKMF, wherein the range information is used as an input parameter to derive the NAS integrity key and the NAS encryption key.

8. The method of claim 7, wherein generating a single parent key comprises: The SKMF generates the single parent key based on the received range information.

9. The method of claim 7, wherein deriving a single parent key comprises: The SKMF generates the single parent key based on the key set identifier KSI without receiving the range information of the NF; as well as The SKMF generates the NAS integrity key and the NAS encryption key based on the generated NAS parent key and the range information.

10. The method of claim 7, further comprising: The SKMF receives a NAS key request with range information and a security algorithm ID from the NF.

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