WO2024171067A1

WO2024171067A1 - Network-based key identification with anonymous suci

Info

Publication number: WO2024171067A1
Application number: PCT/IB2024/051351
Authority: WO
Inventors: Vesa Lehtovirta; Helena VAHIDI MAZINANI
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2023-02-13
Filing date: 2024-02-13
Publication date: 2024-08-22
Anticipated expiration: 2025-08-13

Abstract

A method performed by a user equipment comprises performing a connectivity process with a first network node to generate a first key for use by the UE and the first network node; receiving a correlation identifier, and performing a security protocol process with the first network node using the first key, wherein performing the security protocol process comprises sending, to the first network node, the correlation identifier.

Description

NETWORK-BASED KEY IDENTIFICATION WITH ANONYMOUS SUCI

BACKGROUND

Figure (FIG.) 1 illustrates a process as described in 3GPP TS 33.501 for Registration/ Authentication and protocol data unit (PDU) Session establishment for trusted non- 3GPP access. As illustrated in FIG. 1, the process comprises the following.

0. The UE selects a PLMN and a TNAN for connecting to this PLMN by using the Trusted Non-3GPP Access Network selection procedure specified in TS 23.501 [2] clause 6.3.12. During this procedure, the UE discovers the PLMNs with which the TNAN supports trusted connectivity (e.g. "5G connectivity").

1. A layer-2 connection is established between the UE and the TNAP. In case of IEEE 802.11 [80], this step corresponds to an 802.11 [80] Association. In case of PPP, this step corresponds to a PPP LCP negotiation. In other types of non-3GPP access (e.g. Ethernet), this step may not be required.

2-3. An EAP authentication procedure is initiated. EAP messages shall be encapsulated into layer-2 packets, e.g. into IEEE 802.3/802. lx packets, into IEEE 802.11/802. lx packets, into PPP packets, etc. The UE provides a NAI that triggers the TNAP to send an AAA request to a TNGF. Between the TNAP and TNGF the EAP packets are encapsulated into AAA messages.

4-10. An EAP-5G procedure is executed as specified in clause 7.2.1with the following modifications:

- The EAP-5G packets shall not be encapsulated into IKEv2 packets. The UE shall also include a UE Id in the AN parameters, e.g. a 5G-GUTI if available from a prior registration to the same PLMN.

- A KTNGF as specified in clause Annex A.9 (equivalent to KNSIWF) is created in the UE and in the AMF after the successful authentication. The KTNGF is transferred from the AMF to TNGF in step 10a (within the N2 Initial Context Setup Request).

- The TNAP is a trusted entity. The TNGF shall generate the KTNAP as specified in Annex A.22 and transfers it from TNGF to TNAP in step 10b (within an AAA message).

- After receiving the TNGF key from AMF in step 10a, the TNGF shall send to UE an EAP-Request/5G-Notification packet containing the "TNGF Contact Info", which includes the IP address of TNGF. After receiving an EAP-Response/5G-Notification packet from the UE, the TNGF shall send message 10b containing the EAP-Success packet. 11. The common TNAP key is used by the UE and TNAP to derive security keys according to the applied non-3GPP technology and to establish a security association to protect all subsequent traffic. In case of IEEE 802.11 [80], the KTNAP is the Pairwise Master Key (PMK) and a 4-way handshake is executed (see IEEE 802.11 [80]) which establishes a security context between the WLAN AP and the UE that is used to protect unicast and multicast traffic over the air. All messages between UE and TNAP are encrypted and integrity protected from this step onwards.

NOTE 1 : whether step 11 is performed out of the scope of this document. The current procedure assumes the encryption protection over Layer-2 between UE and TNAP is to be enabled.

12. The UE receives IP configuration from the TNAN, e.g. with DHCP.

13. The UE shall initiate an IKE_INIT exchange with the TNGF. The UE has received the IP address of TNGF during the EAP-5G signalling in step 9b, subsequently, the UE shall initiate an IKE_AUTH exchange and shall include the same UE Id (i.e. SUCI or 5G- GUTI) as in the UE Id provided in step 5. The common Kripse is used for mutual authentication. The key Kripsec is derived as specified in Annex A.22.NULL encryption is negotiated as specified in RFC 2410 [81]. After step 13c, an IPsec SA is established between the UE and TNGF (i.e. a NWt connection) and it is used to transfer all subsequent NAS messages. This IPsec SA does not apply encryption but only apply integrity protection.

14. After the NWtp connection is successfully established, the TNGF responds to AMF with an N2 Initial Context Setup Response message.

15. Finally, the NAS Registration Accept message is sent by the AMF and is forwarded to UE via the established NWt connection.

16-18. The UE initiates a PDU session establishment. This is carried out exactly as specified in TS 23.502 [8] clause 4.12a.5. The TNGF may establish one or more IPSec child SA’s per PDU session.

19. User plane data for the established PDU session is transported between the UE and TNGF inside the established IPSec child SA.

The inventors have recognized various shortcomings of existing solutions, such as the following.

In current 3GPP specifications, including 3GPP TS 33.501, clause 7A.2.1 and 3GPP TS 23.502, clause 4.12a.2, it has been specified that when a User Equipment (UE) registers to 5^th Generation Core (5GC) via trusted non-3GPP access, it first performs authentication with 5GC via the non-3GPP access and Trusted Non-3GPP Gateway Function (TNGF) to get needed keys e.g., for the non-3GPP access, and local Internet Protocol (IP) address. The UE then sets up an IP Security (IPsec) tunnel to the TNGF and rest of the registration procedure is performed over the IPsec tunnel. The keys derived during the authentication are used to secure the IPsec tunnel.

Current specifications require that the UE initiates an IKE_AUTH exchange with the TNGF and provides its identity. The identity provided by the UE in the Internet Key Exchange version 2 (IKEv2) signalling should be the same as the UE Identifier (Id) (SUCI or 5^th Generation (5G)-Globally Unique Temporary Identity (GUTI) included in the Access Network (AN) parameters in the previous authentication run. This enables the TNGF to locate the TNGF key that was created before for this UE, during the authentication. The TNGF key is used for mutual authentication.

For trusted non-3GPP (N3GPP) access, the inventors have identified an issue with the identification of the key KTNGF in the case of using anonymous Subscription Concealed Identifier (SUCI) which is used with some Extensible Authentication Protocol (EAP) methods. Namely, when anonymous SUCI is used, the UE sends string “anonymous” or an empty string instead of the UE specific SUCI value during authentication. Therefore, this value cannot be used in the IKE_AUTH exchange for locating the correct TNGF key.

The following solutions have been proposed so far in 3GPP TR 33.858. The following also includes the clause numbers from the Technical Report (TR).

6.3 Solution #3: Use of anonymous SUCI in trusted non-3GPP access for SNPN

6.3.1 Introduction

This solution solves Key issue #1 in the case of using anonymous SUCI in trusted non- 3GPP access.

When introducing non-3GPP access in Standalone Non-Public Network (SNPN) it is assumed that most security procedures can be reused. However, the use of anonymous SUCI is only applicable to SNPNs so there are not yet any procedures specified for this case in relation to non-3GPP access.

In the current procedures for trusted non-3GPP access in clause 7A.2.1 of TS 33.501, it is specified to use the SUCI/GUTI to map the user to the correct KTNGF in step 13. When using anonymous SUCI, this is not a good solution since an anonymous SUCI is not unique. Instead, another identifier is needed. This solution proposes to use a hash of the key KTNGF as identifier in case anonymous SUCI is used during the authentication towards the SNPN.

This solution defines adaptations of existing procedures needed to support the use of anonymous SUCI in trusted access for SNPN. 6.3.2 Solution details

Procedures in clause 7A.2.1 of TS 33.501 are reused with the following exception:

In step 13, if the construction of SUCI as described in clause 6.12 of TS 33.501 cannot be used, then a new type of identifier is used. The new identifier is proposed to be a hash of the key KTNGF- (potentially using some additional input). It is proposed to send the new identifier using the IDi payload.

It is specified in section 3.5 of RFC 7296 that the ID payload used for transport of IDi can be used to transfer a key identifier by setting the ID Type to ID_KEY_ID. Support of this ID Type is mandatory. The RFC does not specify how such a key identifier is generated. The proposal here is thus to use a hash of the key KTNGF potentially using some additional input to create a key identifier.

6.5 Solution #5: Anonymous authentication during connection establishment in trusted non- 3GPP network access.

6.5.1 Introduction

This is a solution to KI#1.

When a UE accesses a trusted non-3gpp access network, it uses either SUCI or 5G-GUTI for identification. In case of a Non-Public Network (NPN) deployment, the UE might use an anonymous identifier when the EAP method supports its, as specified in TS 33.501 clause 1.5. The anonymous identifier will protect the identity of the UE and makes it impossible to differentiate between a group of UE’s using the same identifier namely the anonymous identifier. As the authentication and key derivation steps are independent of the IPsec establishment, the TNGF cannot link the authentication and derived key to a IKE_AUTH request - as the same identifier is used for multiple devices.

This solution provides a method to fill the gap caused by introducing the anonymous identifier which is standardised in 3GPP TS 33.501 clause 1.5. The solution proposes, that the TNGF creates a unique temporary identifier, shares it after authentication alongside other information necessary to establish the IPsec connection (e.g., TNGF address), to the UE. When the UE initiates the establishment of the IPSec channel, the UE uses the temporary identifier as identifier and thereby enables the TNGF to identify the correct key material (KTNGF) for the session.

The temporary identifier is only applicable when the anonymous identifier is used, therefore it’s proposed as an optional parameter.

6.5.2 Solution details

Procedures in clause 7A.2.1 of 3GPP TS 33.501 are reused with the following exception: - In step 9b, when an anonymous identifier has been used in step 5, transfer a unique temporary identifier, allocated by the TNGF, to the UE alongside the TNGF address.

- In step 13b, use the unique temporary identifier provided in step 9b as IDi, in case an anonymous identifier was used in step 5.

The allocation of a temporary identifier by the TNGF, distributed to the UE, enables the TNGF to identify the KTNGF which is used in the IKE_AUTH procedure in step 13b and c.

6.6 Solution #6: Trusted non-3GPP Access for SNPN

6.6.1 Introduction

This solution addresses key issue #1.

The normal trusted access procedures are used, only if the UE sends an anonymous SUCI, then the TNGF and the UE use the assigned IP address, which is unique within the TNGF, as identifier in the IDi according to RFC 7296.

6.6.2 Solution details

This solution reuses the trusted non-3GPP access authentication procedure in Public Eand Mobile Network (PLMN) scenarios in clause 7A.2.1 of 3GPP TS 33.501 with the following modifications:

If the UE sends an anonymous SUCI in step 5 of the above procedure, then the TNGF will use the IP address, which the TNGF assigns to the UE as unique identifier to bind the security key. In step 13, the UE shall include the ID_IPV4_ADDR or ID_IPV6_ADDR with the assigned IP address in the IDi. The TNGF uses the received IP address to locate the K_TIPSec for the connection.

SUMMARY

In some embodiments of the disclosed subject matter, method performed by a user equipment comprises performing a connectivity process with a first network node to generate a first key for use by the UE and the first network node, receiving a correlation identifier, and performing a security protocol process with the first network node using the first key, wherein performing the security protocol process comprises sending, to the first network node, the correlation identifier.

In certain related embodiments, the security protocol process is for setting up a security protocol between the UE and a communication network.

In certain related embodiments, performing the connectivity process comprises sending, to the first network node, an identifier for the UE. In certain variants, the identifier is one of an anonymous identifier; a Subscription Concealed Identifier, SUCI; an anonymous SUCI; and a 5^th Generation-Global Unique Temporary Identity, 5G-GUTI. In certain variants, the anonymous SUCI is an empty string.

In certain related embodiments, the correlation identifier is received in an encrypted and/or integrity protected message. In certain variants, the method further comprises decrypting and/or verifying the integrity of the encrypted and/or integrity protected message to determine the correlation identifier. In certain variants, the correlation identifier is received in an encrypted and/or integrity protected Non-Access Stratum, NAS, message. In certain variants, the NAS message is a Security Mode Command, SMC, Request message. In certain variants, the NAS message is received after a Security Mode Command, SMC, procedure is completed. In certain variants, the encrypted and/or integrity protected message is received from a second network node. In certain variants, the second network node is an Access and Mobility Management Function, AMF. In certain variants, the encrypted and/or integrity protected message is received from the first network node. In certain variants, the encrypted and/or integrity protected message is encrypted and/or integrity protected using a key of the first network node or a key derived from a key of the first network node.

In some related embodiments, performing the security protocol process comprises sending the correlation identifier to the first network node as an identifier for the UE.

In some related embodiments, the method further comprises receiving a different correlation identifier for a subsequent security protocol process with the first network node or another network node.

In some related embodiments, the connectivity process includes an Extensible Authentication Protocol, EAP, process.

In some related embodiments, the security protocol process is for establishing an Internet Protocol Security, IPSec, tunnel to the first network node.

In some related embodiments, the first network node is a Trusted Non-Third Generation Partnership Project Gateway Function, TNGF.

In some related embodiments, the first key is a K-TNGF key.

In some related embodiments, the connectivity process includes authenticating the UE to a 5^th Generation Core, 5GC.

In some embodiments of the disclosed subject matter, a method performed by a first network node comprises generating a correlation identifier, and sending the correlation identifier to a second network node or to a user equipment, UE. The correlation identifier is for use by the UE in performing a security protocol process.

In some related embodiments, the correlation identifier is sent to the UE. In some such embodiments, the correlation identifier is sent in an encrypted and/or integrity protected message. In some such embodiments, the method further comprises encrypting and/or integrity protecting the correlation identifier prior to sending the correlation identifier to the UE. In some such embodiments, the correlation identifier is sent in an encrypted and/or integrity protected Non- Access Stratum, NAS, message. In some such embodiments, the NAS message is a Security Mode Command, SMC, Request message. In some such embodiments, the NAS message is sent after a Security Mode Command, SMC, procedure is completed with the UE. In some such embodiments, the correlation identifier is encrypted and/or integrity protected with a key. In some such embodiments, the key is any of: a Non-Access Stratum, NAS, key; a key derived from a NAS key; a Security Anchor Function, SEAF, key; a key derived from a SEAF key; a Trusted Non-3^rd Generation Partnership Project Gateway Function, TNGF, key; or a key derived from a TNGF key. In some such embodiments, the first network node is a Trusted Non-3^rd Generation Partnership Project Gateway Function, TNGF, or an Access and Mobility Management Function, AMF.

In certain related embodiments, the correlation identifier is sent to the second network node. In certain related embodiments, the second network node is an Access and Mobility Management Function, AMF.

In certain related embodiments, the method further comprises performing a connectivity process with the UE to generate a first key for use by the UE and the first network node, associating the first key and correlation identifier, and performing a security protocol process with the UE, wherein performing the security protocol process comprises receiving, from the UE, the correlation identifier, and using the correlation identifier to retrieve the first key. In some such embodiments, the connectivity process includes an Extensible Authentication Protocol, EAP, process. In some such embodiments, the connectivity process includes authenticating the UE to a 5^th Generation Core, 5GC. In some such embodiments, performing the connectivity process comprises receiving, from the UE, an identifier for the UE. In some such embodiments, the identifier is one of an anonymous identifier; a Subscription Concealed Identifier, SUCI; an anonymous SUCI; and a 5^th Generation-Global Unique Temporary Identity, 5G-GUTI. In some such embodiments, the anonymous SUCI is an empty string.

In certain related embodiments, the security protocol process is for establishing an Internet Protocol Security, IPSec, tunnel between the UE and the first network node.

In certain related embodiments, the first key is a Trusted Non-Third Generation Partnership Project Gateway Function, TNGF, key.

In some embodiments of the disclosed subject matter, a method performed by a second network node comprises receiving a correlation identifier from a first network node, and sending the correlation identifier to a user equipment, UE, in an encrypted and/or integrity protected message. The correlation identifier is for use by the UE in performing a security protocol process. In some such embodiments, the correlation identifier is sent to the UE in an encrypted and/or integrity protected message. In some such embodiments, the method further comprises encrypting and/or integrity protecting the correlation identifier prior to sending the correlation identifier to the UE. In some such embodiments, the correlation identifier is sent in an encrypted and/or integrity protected Non-Access Stratum, NAS, message. In some such embodiments, the NAS message is a Security Mode Command, SMC, Request message. In some such embodiments, the NAS message is sent after a Security Mode Command, SMC, procedure is completed with the UE.

In certain related embodiments, the correlation identifier is encrypted and/or integrity protected with a key. In some such embodiments, the key is any of: a Non-Access Stratum, NAS, key; a key derived from a NAS key; a Security Anchor Function, SEAF, key; and a key derived from a SEAF key.

In certain related embodiments, the first network node is a Trusted Non-3^rd Generation Partnership Project Gateway Function, TNGF.

In certain related embodiments, the second network node is an Access and Mobility Management Function, AMF.

In some embodiments of the disclosed subject matter, a user equipment, UE, comprises a processor and a memory, wherein the memory contains instructions executable by the processor whereby said UE is operative to perform a method as described above.

In some embodiments of the disclosed subject matter, a network node comprises a processor and a memory, wherein the memory contains instructions executable by the processor whereby the network node is operative to perform a method as described above.

BRIEF DESCRIPITON OF THE DRAWINGS

The drawings illustrate various aspects of the described embodiments. In the drawings, like reference numbers indicate like features.

FIG. 1 illustrates a process as described in 3GPP TS 33.501 for Registration/ Authentication and protocol data unit (PDU) Session establishment for trusted non- 3GPP access.

FIG. 2 illustrates a non-roaming architecture for a 5G Core Network with trusted non- 3GPP access according to some embodiments of the disclosed subject matter. FIG. 3 illustrates a process for Registration/ Authentication and PDU Session establishment for trusted non-3GPP access according to some embodiments of the disclosed subject matter.

FIG. 4 illustrates a process for Registration/ Authentication and PDU Session establishment for trusted non-3GPP access according to some embodiments of the disclosed subject matter.

FIG. 5 illustrates a process for Registration/ Authentication and PDU Session establishment for trusted non-3GPP access according to some embodiments of the disclosed subject matter.

FIG. 6 illustrates an example of a communication system in accordance with some embodiments of the disclosed subject matter.

FIG. 7 shows a wireless device or UE in accordance with some embodiments of the disclosed subject matter.

FIG. 8 shows a network node in accordance with some embodiments of the disclosed subject matter.

FIG. 9 is a block diagram illustrating a virtualization environment in which functions implemented by some embodiments may be virtualized.

DETAILED DESCRIPTION

The following description presents various embodiments of the disclosed subject matter. These embodiments are presented as teaching examples and are not intended to limit the scope of the disclosed subject matter.

Certain aspects of the disclosure and their embodiments may provide solutions to the above or other challenges. The techniques described herein provide that when a device (e.g., UE) is establishing connectivity to a mobile network (e.g., 5GC) via an access network (e.g., a trusted non-3GPP access network (TNAN) and the UE sends an anonymous SUCI , e.g., in step 5 of Figure 7A.2.1-1 from clause 2.2.3 of 3GPP TS 33.501 to the network, the network generates a correlation identifier (ID), protects it with a key and sends it to the UE. The correlation ID is a reference to a key which the UE and the network (e.g., TNGF) can, in a later phase, use to secure communication (e.g., to establish IKE/IPSec in step 13 of Figure 7A.2.1-1).

There are several variants how this can be done. In one embodiment, the TNGF can generate the correlation ID, protect it with K-TNGF, and send it to the UE. In another embodiment the TNGF can generate the correlation ID and send it to the Access and Mobility Management Function (AMF). The AMF protects it with a Non-Access Stratum (NAS) key and sends it to the UE, e.g., in a protected NAS message. In another embodiment, the AMF can generate the correlation ID, protect it with a NAS key, and send it to the UE, and also send it to the TNGF. When the UE later sends the IKE_AUTH message in step 13 (see Figure 1), the UE includes the same correlation ID in the IDi field. The correlation ID allows the TNGF to locate the correct TNGF key and successfully perform IKE process.

While in the above embodiments the reception of the anonymous SUCI is a trigger to the network to generate the correlation ID, it will be appreciated that this trigger is not required for the correlation ID to be generated. That is, the solutions described herein can also be applied in the (generic) case where the UE sends a normal SUCI or a 5G-GUTI. Thus, reference in the following description to an anonymous SUCI should be not be considered limiting.

Thus, some embodiments provide that, when a device is establishing connectivity to a mobile network (e.g., 5GC) via an access network (e.g., trusted non-3GPP access network), the network (e.g., TNGF or AMF) generates a correlation identifier, protects it with a key and sends it to the UE. As noted above, these actions by the network of generating the correlation ID, protecting it with a key and sending it to the UE can be performed by a single network node, e.g. a TNGF or an AMF, or it can be performed collectively by multiple network nodes, e.g. a TNGF can generate the correlation ID send it to the AMF, and the AMF protects the correlation ID with a key and sends it to the UE.

When the UE later starts another security protocol or authentication run/process (e.g., IKE_AUTH exchange) with the network (e.g., TNGF), the UE sends the same correlation identifier in the security protocol or authentication run/process (e.g., in IKE_AUTH exchange) that it received from the network.

In some embodiments, the connectivity process may include an authentication run/process (e.g., EAP) which results in a key generated in the UE and network side (e.g., TNGF and/or AMF).

In some embodiments, the correlation ID may be generated by a first network node (e.g., TNGF) or second network node (e.g., AMF). In some embodiments, the TNGF can generate the correlation ID, protect it with a key (e.g. K-TNGF) and send it to the UE. In other embodiments, the TNGF can generate the correlation ID and send it to the AMF, and the AMF protects it with a key (e.g. a NAS key) and sends it to the UE. In yet other embodiments, the AMF can generate the correlation ID, protect it with a NAS key and send it to the UE.

In some embodiments, during the connectivity process the device (UE) may send an indication of an anonymous identifier (like an anonymous SUCI). The indication may trigger the generation of the correlation ID in the network.

The correlation identifier enables the network node (e.g., TNGF) to correlate two protocol runs. More specifically, the correlation identifier can help the network node (e.g., TNGF) to find the key which was generated during the first protocol run/process (e.g., EAP) and to use the key for successfully performing the second protocol run/process (e.g., IKE exchange).

Certain embodiments may provide one or more of the following technical advantage(s). The techniques provide that, for trusted N3GPP access, a correlation identifier is generated by the network, securely transferred to the UE, and is used by the UE and network to identify the correct key (e.g. K-TNGF) for the UE when the UE uses an anonymous SUCI, or other type of identifier, such as a regular SUCI or 5G-GUTI.

Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

An exemplary communication system to which the techniques described herein can be applied is shown in FIG. 2, which illustrates a process for non-roaming architecture for 5G Core Network with trusted non-3GPP access according to some embodiments of the disclosed subject matter.

As noted above, the techniques described herein provide that, when a device is establishing connectivity to a mobile network (e.g., 5GC) via an access network (e.g., trusted non-3GPP access network), the network (e.g., TNGF or AMF) generates a correlation identifier, protects it with a key and sends it to the UE. These actions by the network of generating the correlation ID, protecting it with a key and sending it to the UE can be performed by a single network node, e.g. a TNGF or an AMF, or it can be performed across multiple network nodes, e.g. a TNGF can generate the correlation ID send it to the AMF, and the AMF protects the correlation ID with a key and sends it to the UE.

Embodiment 1 : AMF generates correlation ID, protected with NAS key

An embodiment of the new techniques presented herein is illustrated in FIG. 3, which which illustrates a process for Registration/ Authentication and PDU Session establishment for trusted non-3GPP access.

1. A layer-2 connection is established between the UE and the TNAP. In case of

IEEE 802.11 [80], this step corresponds to an 802.11 [80] Association. In case of PPP, this step corresponds to a PPP LCP negotiation. In other types of non-3GPP access (e.g. Ethernet), this step may not be required. -3. An EAP authentication procedure is initiated. EAP messages shall be encapsulated into layer-2 packets, e.g. into IEEE 802.3/802. lx packets, into IEEE 802.11/802. lx packets, into PPP packets, etc. The UE provides a NAI that triggers the TNAP to send an AAA request to a TNGF. Between the TNAP and TNGF the EAP packets are encapsulated into AAA messages. -10. An EAP-5G procedure is executed as specified in clause 7.2.1with the following modifications:

- The EAP-5G packets shall not be encapsulated into IKEv2 packets. The UE shall also include a UE Id in the AN parameters or in Registration Request or both, e.g. a 5G- GUTI if available from a prior registration to the same PLMN or SUCI or an anonymous SUCI. Upon receiving a UE-Id the AMF generates a correlation ID. The AMF protects the correlation ID with a NAS key (or key derived from NAS key or K- SEAF or a key derived from K-SEAF) and sends the correlation ID to the UE (e.g., via the TNGF) in a protected NAS message (or another message). The correlation ID is confidentiality or integrity protected or both. When the UE receives the protected correlation ID, the UE unprotects the correlation ID. E.g., the UE verifies the integrity protection and/or decrypts the Correlation ID. The UE can then use the correlation ID to refer to the key (e.g., K-TNGF or K-TIPsec) to be used for running IKE/IPsec with the TNGF in step 13.

Example embodiments are as follows:

Option A, the AMF sends the Correlation ID in integrity protected Security Mode Command Request (SMC) in step 9a and 9b. The UE unprotects the correlation ID (e.g., as part of unprotecting the protected NAS message) and then uses the correlation ID in step 13.

The SMC Request is today only integrity protected. In an alternative aspect, the correlation ID can be also sent encrypted in the SMC.

Option B, after the SMC procedure has completed, the correlation ID can be sent in a separate integrity and/or confidentiality protected NAS message (e.g., DL NAS transport message with step 10a) from the AMF to the TNGF which forwards it to the UE in step 10b. The UE unprotects the correlation ID (e.g., as part of unprotecting the protected NAS message) and then uses the correlation ID in step 13.

In both options A and B above, the AMF also sends the correlation ID to the TNGF in step 10a in Initial context setup request. Alternatively, the AMF sends the correlation to the TNGF in step 9a. In both cases the correlation ID is sent both inside of the NAS message (to the UE) and outside of NAS message (to the TNGF). Sending outside of NAS message is not shown in figure above.

- After receiving the TNGF key from AMF in step 10a, the TNGF shall send to UE an EAP-Request/5G-Notification packet containing the "TNGF Contact Info", which includes the IP address of TNGF. After receiving an EAP-Response/5G-Notification packet from the UE, the TNGF shall send message 10b containing the EAP-Success packet.

11. The common TNAP key is used by the UE and TNAP to derive security keys according to the applied non-3GPP technology and to establish a security association to protect all subsequent traffic. In case of IEEE 802.11 [80], the KTNAP is the Pairwise Master Key (PMK) and a 4-way handshake is executed (see IEEE 802.11 [80]) which establishes a security context between the WLAN AP and the UE that is used to protect unicast and multicast traffic over the air. All messages between UE and TNAP are encrypted and integrity protected from this step onwards.

12. The UE receives IP configuration from the TNAN, e.g. with DHCP.

13. The UE shall initiate an IKE_INIT exchange with the TNGF. The UE has received the IP address of TNGF and correlation ID during the EAP-5G signalling, subsequently, the UE shall initiate an IKE_AUTH exchange and shall include the received a correlation ID as the IDi value in IKE_AUTH. The correlation ID is used by the TNGF to identify which KTNGF (or key derived from KTNGF such as KriPSec ) is used in the IKE_AUTH procedure. The common KriPSec is used for mutual authentication. The key Knpsec is derived as specified in Annex A.22. NULL encryption is negotiated as specified in

RFC 2410 [81]. After step 13c, an IPsec SA is established between the UE and TNGF (i.e. a NWt connection) and it is used to transfer all subsequent NAS messages. This IPsec SA does not apply encryption but only apply integrity protection. 14. After the NWtp connection is successfully established, the TNGF responds to AMF with an N2 Initial Context Setup Response message.

16-19. Although not shown in the figure, these steps are as described in Clause 7A.2.1 of 3GPP TS 33.501.

Embodiment 2: TNGF generates correlation ID, protected with NAS key

Another embodiment of the new techniques presented herein is illustrated in FIG. 4, which illustrates a process for Registration/ Authentication and PDU Session establishment for trusted non-3GPP access with additions for Embodiment 2. For the sake of brevity, the description of steps in FIG. 4 (the modified version of Figure 7A.2.1-1) that are consistent with Embodiment 1 and FIG. 3 above have been omitted, and the provided description relates to the differences between Embodiment 2 and Embodiment 1.

During the UE’s registration to 5GC via an access network (e.g., trusted non-3gPP access network) and when the TNGF receives SUCI, 5G-GUTI or an anonymous SUCI (e.g., in step 5), the TNGF generates a correlation ID. The TNGF sends the correlation ID to the AMF. The AMF protects the correlation ID with a NAS key (or key derived from NAS key or K-SEAF or a key derived from K-SEAF) and sends the correlation ID to the UE (e.g., via the TNGF) in a protected NAS message (or another message). The correlation ID is confidentiality or integrity protected or both. When the UE receives the protected correlation ID, the UE unprotects the correlation ID. E.g., the UE verifies the integrity protection and/or decrypts the Correlation ID. The UE can then use the correlation ID to refer to the key to be used for running IKE/IPsec with the TNGF in step 13. Example embodiments are as follows:

Option A: the TNGF sends the correlation ID to the AMF, for example in step 6b. The AMF then sends it to the UE in a protected SMC (e.g., in step 9). The UE then uses the Correlation ID in IKE in step 13.

Option B: the TNGF sends the Correlation ID to the AMF, for example in in step 6b or step 9d. The AMF then sends the correlation ID to the UE in a protected NAS message after the SMC procedure, e.g., in step 10 (e.g., in DL NAS transport). The UE then uses the Correlation ID in step 13.

Option C (not shown in FIG. 4): the TNGF sends the Correlation ID to the AMF, for example in step 9d. The AMF calculates a MAC for integrity protection of the Correlation ID using the NAS integrity key and NAS DL count. The AMF sends the MAC, DL count (or some LSB of DL count) and optionally the Correlation ID to the TNGF. The TNGF sends the MAC, DL count (or some LSB of DL count) and Correlation ID to the UE, e.g., in step 10. The UE will locate the NAS security context and verifies the MAC. The UE then uses the Correlation ID in step 13.

Embodiment 3: TNGF generates the correlation ID, protected with TNGF key

Another embodiment of the new techniques presented herein is illustrated respect to FIG. 5, which illustrates a process for Registration/ Authentication and PDU Session establishment for trusted non-3GPP access. For brevity the description of steps in FIG. 5 (the modified version of Figure 7A.2.1-1) that are consistent with Embodiment 1 and FIG. 3 above has been omitted, and the provided description relates to the differences between Embodiment 3 and Embodiment 1.

During the UE’s registration to 5GC via an access network (e.g., trusted non-3GPP access network) and when the TNGF receives SUCI, 5G-GUTI or an anonymous SUCI (e.g., in step 5), the TNGF generates the correlation ID.

The TNGF protects the correlation ID with TNGF key or a key derived from TNGF key. The correlation ID is either integrity or confidentiality protected or both. In more detail, the integrity protection can happen for example in the following way: MAC of the correlation ID is sent to the UE together with the correlation ID. The MAC is calculated using e.g., the correlation ID as input and KTNGF or a key derived from the KTNGF- Another example is to use authenticated encryption which provides both integrity and confidentiality protection.

When the UE receives the protected correlation ID, derives the same key which the TNGF used (this can happen also before the UE received the protected correlation ID) and the UE unprotects the correlation ID. I.e., the UE verifies the integrity protection (e.g., by verifying the MAC) and/or decrypts the correlation ID.

The UE can then use the correlation ID in step 13. While this Embodiment has elements in common with solution#5 in TR 33.858, the disclosed techniques protect the transmission of the correlation with Ktngf.

FIG. 6 illustrates an example of a communication system 6100 in accordance with some embodiments.

In the example, the communication system 6100 includes a telecommunication network 6102 that includes an access network 6104, such as a radio access network (RAN), and a core network 6106, which includes one or more core network nodes 6108. The access network 6104 includes one or more access network nodes, such as access network nodes 6110a and 6110b (one or more of which may be generally referred to as access network nodes 6110), or any other similar 3^rd Generation Partnership Project (3GPP) access node or non-3GPP access point (AP). The access network nodes 6110 facilitate direct or indirect connection of wireless devices (also referred to interchangeably herein as user equipment (UE)), such as by connecting UEs 6112a, 6112b, 6112c, and 6112d (one or more of which may be generally referred to as UEs 6112) to the core network 6106 over one or more wireless connections. The access network nodes 6110 may be, for example, access points (APs) (e.g. radio access points), base stations (BSs) (e.g. radio base stations, Node Bs, evolved Node Bs (eNBs) and New Radio (NR) NodeBs (gNBs)).

In some embodiments, the access network 6104 can be a Trusted Non-3GPP Access Network (TNAN), and the core network 6106 can be a 5GC. The network nodes 6110 in the TNAN 6104 can be Trusted Non-3GPP Access Points (TNAPs). Although not shown in FIG. 6, the TNAN 6104 can include a Trusted Non-3GPP Gateway Function (TNGF). The core network node(s) 6108 in the 5GC 6106 can include an Access and Mobility Management Function (AMF) and an Authentication Server Function (AUSF).

Unless otherwise indicated, the term ‘network node’ is used herein to refer to both (trusted non-3GPP) access network nodes 6110 and core network nodes 6108.

Example wireless communications over a wireless connection include transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 6100 may include any number of wired or wireless networks, network nodes, UEs, and/or any other components or systems that may facilitate or participate in the communication of data and/or signals whether via wired or wireless connections. The communication system 6100 may include and/or interface with any type of communication, telecommunication, data, cellular, radio network, and/or other similar type of system.

The wireless devices/UEs 6112 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and/or operable to communicate wirelessly with the network nodes 6110 and other communication devices. Similarly, the access network nodes 6110 are arranged, capable, configured, and/or operable to communicate directly or indirectly with the UEs 6112 and/or with other network nodes or equipment in the telecommunication network 6102 to enable and/or provide network access, such as wireless network access, and/or to perform other functions, such as administration in the telecommunication network 6102.

In the depicted example, the core network 6106 connects the access network nodes 6110 to one or more hosts, such as host 6116. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 6106 includes one more core network nodes (e.g. core network node 6108) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the wireless devices/UEs, access network nodes, and/or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 6108. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDE), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and/or a User Plane Function (UPF).

The host 6116 may be under the ownership or control of a service provider other than an operator or provider of the access network 6104 and/or the telecommunication network 6102, and may be operated by the service provider or on behalf of the service provider. The host 6116 may host a variety of applications to provide one or more services. Examples of such applications include the provision of live and/or pre-recorded audio/video content, data collection services, for example, retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

As a whole, the communication system 6100 of FIG. 6 enables connectivity between the wireless devices/UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and/or other suitable 2^nd Generation (2G), 3^rd Generation (3G), 4^th Generation (4G), 5^th Generation (5G) standards, or any applicable future generation standard (e.g. 6^th Generation (6G)); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and/or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and/or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

In some examples, the telecommunication network 6102 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network 6102 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 6102. For example, the telecommunications network 6102 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and/or Massive Machine Type Communication (mMTC)/Massive Internet of Things (loT) services to yet further UEs.

In some examples, the UEs 6112 are configured to transmit and/or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 6104 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 6104. Additionally, a UE may be configured for operating in single- or multi-radio access technology (RAT) or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e. being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UTRA (UMTS Terrestrial Radio Access) Network) New Radio - Dual Connectivity (EN-DC).

In the example illustrated in FIG. 6, the hub 6114 communicates with the access network 6104 to facilitate indirect communication between one or more UEs (e.g. UE 6112c and/or 6112d) and access network nodes (e.g. access network node 6110b). In some examples, the hub 6114 may be a controller, router, a content source and analytics node, or any of the other communication devices described herein regarding UEs. For example, the hub 6114 may be a broadband router enabling access to the core network 6106 for the UEs. As another example, the hub 6114 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 6110, or by executable code, script, process, or other instructions in the hub 6114. As another example, the hub 6114 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 6114 may be a content source. For example, for a UE that is a Virtual Reality VR headset, display, loudspeaker or other media delivery device, the hub 6114 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 6114 then provides to the UE either directly, after performing local processing, and/or after adding additional local content. In still another example, the hub 6114 acts as a proxy server or orchestrator for the UEs, in particular in if one or more of the UEs are low energy Internet of Things (loT) devices.

The hub 6114 may have a constant/persistent or intermittent connection to the network node 6110b. The hub 6114 may also allow for a different communication scheme and/or schedule between the hub 6114 and UEs (e.g. UE 6112c and/or 6112d), and between the hub 6114 and the core network 6106. In other examples, the hub 6114 is connected to the core network 6106 and/or one or more UEs via a wired connection. Moreover, the hub 6114 may be configured to connect to a Machine-to-Machine (M2M) service provider over the access network 6104 and/or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 6110 while still connected via the hub 6114 via a wired or wireless connection. In some embodiments, the hub 6114 may be a dedicated hub - that is, a hub whose primary function is to route communications to/from the UEs from/to the network node 6110b. In other embodiments, the hub 6114 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 6110b, but which is additionally capable of operating as a communication start and/or end point for certain data channels.

FIG. 7 shows a wireless device or UE 7200 in accordance with some embodiments of the disclosed subject matter.

As used herein, a UE refers to a device capable, configured, arranged and/or operable to communicate wirelessly with network nodes and/or other UEs. Examples of a wireless device/UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless camera, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle-mounted or vehicle embedded/integrated wireless device, etc. Other examples include any UE identified by the 3rd Generation Partnership Project (3GPP), including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and/or an enhanced MTC (eMTC) UE.

A wireless device/UE may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle- to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and/or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g. a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g. a smart power meter). The UE 7200 includes processing circuitry 7202 that is operatively coupled via a bus 7204 to an input/output interface 7206, a power source 7208, a memory 7210, a communication interface 7212, and/or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in FIG. 7. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

The processing circuitry 7202 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 7210. The processing circuitry 7202 may be implemented as one or more hardware-implemented state machines (e.g. in discrete logic, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 7202 may include multiple central processing units (CPUs). The processing circuitry 7202 may be operable to provide, either alone or in conjunction with other UE 7200 components, such as the memory 7210, to provide UE 7200 functionality. For example, the processing circuitry 7202 may be configured to cause the UE 7202 to perform the methods described herein.

In the example, the input/output interface 7206 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and/or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 7200. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g. a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

In some embodiments, the power source 7208 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g. an electricity outlet), photovoltaic device, or power cell, may be used. The power source 7208 may further include power circuitry for delivering power from the power source 7208 itself, and/or an external power source, to the various parts of the UE 7200 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 7208. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 7208 to make the power suitable for the respective components of the UE 7200 to which power is supplied.

The memory 7210 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable readonly memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 7210 includes one or more application programs 7214, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 7216. The memory 7210 may store, for use by the UE 7200, any of a variety of various operating systems or combinations of operating systems.

The memory 7210 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a Universal Subscriber Identity Module (USIM) and/or integrated SIM (ISIM), other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ The memory 7210 may allow the UE 7200 to access instructions, application programs and the like, stored on transitory or non- transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory 7210, which may be or comprise a device-readable storage medium.

The processing circuitry 7202 may be configured to communicate with an access network or other network using the communication interface 7212. The communication interface 7212 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 7222. The communication interface 7212 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g. another UE or a network node in an access network). Each transceiver may include a transmitter 7218 and/or a receiver 7220 appropriate to provide network communications (e.g. optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 7218 and receiver 7220 may be coupled to one or more antennas (e.g. antenna 7222) and may share circuit components, software or firmware, or alternatively be implemented separately.

In some embodiments, communication functions of the communication interface 7212 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) or other Global Navigation Satellite System (GNSS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and/or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, NR, UMTS, WiMax, Ethernet, transmission control protocol/internet protocol (TCP/IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 7212, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g. once every 15 minutes if it reports the sensed temperature), random (e.g. to even out the load from reporting from several sensors), in response to a triggering event (e.g. when moisture is detected an alert is sent), in response to a request (e.g. a user initiated request), or a continuous stream (e.g. a live video feed of a patient).

As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or controls a robotic arm performing a medical procedure according to the received input. A UE, when in the form of an loT device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are devices which are or which are embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door/window sensor, a flood/moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or VR, a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and/or software in dependence on the intended application of the loT device in addition to other components as described in relation to the UE 7200 shown in FIG. 7.

As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another UE and/or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation.

In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g. by controlling an actuator) to increase or decrease the drone’s speed. The first and/or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

FIG. 8 shows a network node 8300 in accordance with some embodiments of the disclosed subject matter. As used herein, network node refers to equipment capable, configured, arranged and/or operable to communicate directly or indirectly with a UE and/or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access network nodes such as APs (e.g. radio access points), base stations (BSs) (e.g. radio base stations, Node Bs, evolved Node Bs (eNBs) and NR NodeBs (gNBs)) TNAPs and/or TNGFs. Other examples of network nodes include, but are not limited to, core network nodes such as nodes that include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and/or a User Plane Function (UPF).

Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and/or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell/multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g. Evolved Serving Mobile Location Centers (E-SMLCs)), and/or Minimization of Drive Tests (MDTs).

The network node 8300 includes processing circuitry 8302, a memory 8304, a communication interface 8306, and a power source 8308, and/or any other component, or any combination thereof. The network node 8300 may be composed of multiple physically separate components (e.g. a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node 8300 comprises multiple separate components (e.g. BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the network node 8300 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g. separate memory 8304 for different RATs) and some components may be reused (e.g. a same antenna 8310 may be shared by different RATs). The network node 8300 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 8300, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 8300.

The processing circuitry 8302 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application- specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and/or encoded logic operable to provide, either alone or in conjunction with other network node 8300 components, such as the memory 8304, to provide network node 8300 functionality. For example, the processing circuitry 8302 may be configured to cause the network node to perform the methods described herein.

In some embodiments, the processing circuitry 8302 includes a system on a chip (SOC). In some embodiments, the processing circuitry 8302 includes one or more of radio frequency (RF) transceiver circuitry 8312 and baseband processing circuitry 8314. In some embodiments, the radio frequency (RF) transceiver circuitry 8312 and the baseband processing circuitry 8314 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 8312 and baseband processing circuitry 8314 may be on the same chip or set of chips, boards, or units.

The memory 8304 may comprise any form of volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or any other volatile or non-volatile, non-transitory device -readable and/or computer-executable memory devices that store information, data, and/or instructions that may be used by the processing circuitry 8302. The memory 8304 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and/or other instructions capable of being executed by the processing circuitry 8302 and utilized by the network node 8300. The memory 8304 may be used to store any calculations made by the processing circuitry 8302 and/or any data received via the communication interface 8306. In some embodiments, the processing circuitry 8302 and memory 8304 is integrated.

The communication interface 8306 is used in wired or wireless communication of signalling and/or data between network nodes, the access network, the core network, and/or a UE. As illustrated, the communication interface 8306 comprises port(s)/terminal(s) 8316 to send and receive data, for example to and from a network over a wired connection.

In embodiments where the network node 8300 is an access network node (e.g. a TNAP), the communication interface 8306 also includes radio front-end circuitry 8318 that may be coupled to, or in certain embodiments a part of, the antenna 8310. In embodiments where the network node 8300 is a core network node, or where the network node 8300 is a TNGF, the core network node may not include radio front-end circuitry 8318 and antenna 8310. Radio front-end circuitry 8318 comprises filters 8320 and amplifiers 8322. The radio front-end circuitry 8318 may be connected to an antenna 8310 and processing circuitry 8302. The radio front-end circuitry may be configured to condition signals communicated between antenna 8310 and processing circuitry 8302. The radio front-end circuitry 8318 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 8318 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 8320 and/or amplifiers 8322. The radio signal may then be transmitted via the antenna 8310. Similarly, when receiving data, the antenna 8310 may collect radio signals which are then converted into digital data by the radio front-end circuitry 8318. The digital data may be passed to the processing circuitry 8302. In other embodiments, the communication interface may comprise different components and/or different combinations of components.

In certain alternative embodiments, the access network node 8300 does not include separate radio front-end circuitry 8318, instead, the processing circuitry 8302 includes radio front-end circuitry and is connected to the antenna 8310. Similarly, in some embodiments, all or some of the RF transceiver circuitry 8312 is part of the communication interface 8306. In still other embodiments, the communication interface 8306 includes one or more ports or terminals 8316, the radio front-end circuitry 8318, and the RF transceiver circuitry 8312, as part of a radio unit (not shown), and the communication interface 8306 communicates with the baseband processing circuitry 8314, which is part of a digital unit (not shown).

The antenna 8310 may include one or more antennas, or antenna arrays, configured to send and/or receive wireless signals. The antenna 8310 may be coupled to the radio front-end circuitry 8318 and may be any type of antenna capable of transmitting and receiving data and/or signals wirelessly. In certain embodiments, the antenna 8310 is separate from the network node 8300 and connectable to the network node 8300 through an interface or port.

The antenna 8310, communication interface 8306, and/or the processing circuitry 8302 may be configured to perform any receiving operations and/or certain obtaining operations described herein as being performed by the network node. Any information, data and/or signals may be received from a UE, another network node and/or any other network equipment. Similarly, the antenna 8310, the communication interface 8306, and/or the processing circuitry 8302 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and/or signals may be transmitted to a UE, another network node and/or any other network equipment.

The power source 8308 provides power to the various components of network node 8300 in a form suitable for the respective components (e.g. at a voltage and current level needed for each respective component). The power source 8308 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 8300 with power for performing the functionality described herein. For example, the network node 8300 may be connectable to an external power source (e.g. the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 8308. As a further example, the power source 8308 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

Embodiments of the network node 8300 may include additional components beyond those shown in FIG. 8 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and/or any functionality necessary to support the subject matter described herein. For example, the network node 8300 may include user interface equipment to allow input of information into the network node 8300 and to allow output of information from the network node 8300. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 8300.

FIG. 9 is a block diagram illustrating a virtualization environment 9500 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 9500 hosted by one or more of hardware nodes, such as a hardware computing device that operates as an access network node, a TNAP, a TNGF, a wireless device/UE, or a core network node. Further, in embodiments in which the virtual node does not require radio connectivity (e.g. a TNGF or a core network node), then the node may be entirely virtualized.

Applications 9502 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment 9500 to implement some of the features, functions, and/or benefits of some of the embodiments disclosed herein.

Hardware 9504 includes processing circuitry, memory that stores software and/or instructions executable by hardware processing circuitry, and/or other hardware devices as described herein, such as a network interface, input/output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 9506 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 9508a and 9508b (one or more of which may be generally referred to as VMs 9508), and/or perform any of the functions, features and/or benefits described in relation with some embodiments described herein. The virtualization layer 9506 may present a virtual operating platform that appears like networking hardware to the VMs 9508.

The VMs 9508 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 9506. Different embodiments of the instance of a virtual appliance 9502 may be implemented on one or more of VMs 9508, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

In the context of NFV, a VM 9508 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs 9508, and that part of hardware 9504 that executes that VM, be it hardware dedicated to that VM and/or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 9508 on top of the hardware 9504 and corresponds to the application 9502.

Hardware 9504 may be implemented in a standalone network node with generic or specific components. Hardware 9504 may implement some functions via virtualization. Alternatively, hardware 9504 may be part of a larger cluster of hardware (e.g. such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 9510, which, among others, oversees lifecycle management of applications 9502. In some embodiments, hardware 9504 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signalling can be provided with the use of a control system 9512 which may alternatively be used for communication between hardware nodes and radio units.

Although the computing devices described herein (e.g. UEs, network nodes) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and/or software needed to perform the tasks, features, functions and methods disclosed herein. Determining, calculating, obtaining or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and/or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and/or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored on in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer- readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer- readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole, and/or by end users and a wireless network generally.

The foregoing merely illustrates certain principles of the disclosure. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in view of the teachings herein. It will thus be appreciated that those skilled in the art will be able to devise numerous systems, arrangements, and procedures that, although not explicitly shown or described herein, embody the principles of the disclosure and can be thus within the scope of the disclosure. Various exemplary embodiments can be used together with one another, as well as interchangeably therewith, as should be understood by those having ordinary skill in the art.

Claims

CLAIMS:

1. A method performed by a user equipment, comprising: performing a connectivity process with a first network node to generate a first key for use by the UE and the first network node; receiving a correlation identifier; and performing a security protocol process with the first network node using the first key, wherein performing the security protocol process comprises sending, to the first network node, the correlation identifier.

2. The method of claim 1, wherein the security protocol process is for setting up a security protocol between the UE and a communication network.

3. The method of claim 1 or 2, wherein performing the connectivity process comprises sending, to the first network node, an identifier for the UE.

4. The method of claim 3, wherein the identifier is one of an anonymous identifier; a Subscription Concealed Identifier, SUCI; an anonymous SUCI; and a 5^th Generation-Global Unique Temporary Identity, 5G-GUTI.

5. The method of claim 4, wherein the anonymous SUCI is an empty string.

6. The method of any of claims 1-5, wherein the correlation identifier is received in an encrypted and/or integrity protected message.

7. The method of claim 6, wherein the method further comprises: decrypting and/or verifying the integrity of the encrypted and/or integrity protected message to determine the correlation identifier.

8. The method of claim 7, wherein the correlation identifier is received in an encrypted and/or integrity protected Non-Access Stratum, NAS, message.

9. The method of claim 8, wherein the NAS message is a Security Mode Command, SMC, Request message.

10. The method of claim 8, wherein the NAS message is received after a Security Mode Command, SMC, procedure is completed.

11. The method of any of claims 7-10, wherein the encrypted and/or integrity protected message is received from a second network node.

12. The method of claim 11, wherein the second network node is an Access and Mobility Management Function, AMF.

13. The method of claim 7, wherein the encrypted and/or integrity protected message is received from the first network node.

14. The method of claim 13, wherein the encrypted and/or integrity protected message is encrypted and/or integrity protected using a key of the first network node or a key derived from a key of the first network node.

15. The method of any of claims 1-14, wherein performing the security protocol process comprises sending the correlation identifier to the first network node as an identifier for the UE.

16. The method of any of claims 1-15, wherein the method further comprises receiving a different correlation identifier for a subsequent security protocol process with the first network node or another network node.

17. The method of any of claims 1-16, wherein the connectivity process includes an Extensible Authentication Protocol, EAP, process.

18. The method of any of claims 1-17, wherein the security protocol process is for establishing an Internet Protocol Security, IPSec, tunnel to the first network node.

19. The method of any of claims 1-18, wherein the first network node is a Trusted Non-Third Generation Partnership Project Gateway Function, TNGF.

20. The method of claim 19, wherein the first key is a K-TNGF key.

21. The method of any of claims 1-20, wherein the connectivity process includes authenticating the UE to a 5^th Generation Core, 5GC.

22. A method performed by a first network node, comprising: generating a correlation identifier; and sending the correlation identifier to a second network node or to a user equipment, UE; wherein the correlation identifier is for use by the UE in performing a security protocol process.

23. The method of claim 22, wherein the correlation identifier is sent to the UE.

24. The method of claim 23, wherein the correlation identifier is sent in an encrypted and/or integrity protected message.

25. The method of claim 24, wherein the method further comprises: encrypting and/or integrity protecting the correlation identifier prior to sending the correlation identifier to the UE.

26. The method of claim 24 or 25, wherein the correlation identifier is sent in an encrypted and/or integrity protected Non-Access Stratum, NAS, message.

27. The method of claim 26, wherein the NAS message is a Security Mode Command, SMC, Request message.

28. The method of claim 26, wherein the NAS message is sent after a Security Mode Command, SMC, procedure is completed with the UE.

29. The method of any of claims 24-28, wherein the correlation identifier is encrypted and/or integrity protected with a key.

30. The method of claim 29, wherein the key is any of: a Non-Access Stratum, NAS, key; a key derived from a NAS key; a Security Anchor Function, SEAF, key; a key derived from a SEAF key; a Trusted Non-3^rd Generation Partnership Project Gateway Function, TNGF, key; or a key derived from a TNGF key.

31. The method of any of claims 23-30, wherein the first network node is a Trusted Non-3^rd Generation Partnership Project Gateway Function, TNGF, or an Access and Mobility Management Function, AMF.

32. The method of claim 22, wherein the correlation identifier is sent to the second network node.

33. The method of claim 32, wherein the second network node is an Access and Mobility Management Function, AMF.

34. The method of any of claims 22-33, wherein the method further comprises: performing a connectivity process with the UE to generate a first key for use by the UE and the first network node; associating the first key and correlation identifier; and performing a security protocol process with the UE, wherein performing the security protocol process comprises receiving, from the UE, the correlation identifier, and using the correlation identifier to retrieve the first key.

35. The method of claim 34, wherein the connectivity process includes an Extensible Authentication Protocol, EAP, process.

36. The method of claim 34 or 35, wherein the connectivity process includes authenticating the UE to a 5^th Generation Core, 5GC.

37. The method of any of claims 34-36, wherein performing the connectivity process comprises receiving, from the UE, an identifier for the UE.

38. The method of claim 37, wherein the identifier is one of an anonymous identifier; a Subscription Concealed Identifier, SUCI; an anonymous SUCI; and a 5^th Generation-Global Unique Temporary Identity, 5G-GUTI.

39. The method of claim 38, wherein the anonymous SUCI is an empty string.

40. The method of any of claims 34-39, wherein the security protocol process is for establishing an Internet Protocol Security, IPSec, tunnel between the UE and the first network node.

41. The method of any of claims 34-40, wherein the first key is a Trusted Non-Third Generation Partnership Project Gateway Function, TNGF, key.

42. A method performed by a second network node, comprising: receiving a correlation identifier from a first network node or the second network node, wherein the first network node is a Trusted Non-3^rd Generation Partnership Project Gateway Function, TNGF, and the second network node is an Access and Mobility Management Function (AMF); and sending the correlation identifier to a user equipment, UE, in an encrypted and/or integrity protected message; wherein the correlation identifier is for use by the UE in performing a security protocol process.

43. The method of claim 42, wherein the correlation identifier is sent to the UE in an encrypted and/or integrity protected message.

44. The method of claim 43, wherein the method further comprises: encrypting and/or integrity protecting the correlation identifier prior to sending the correlation identifier to the UE.

45. The method of claim 43 or 44, wherein the correlation identifier is sent in an encrypted and/or integrity protected Non-Access Stratum, NAS, message.

46. The method of claim 45, wherein the NAS message is a Security Mode Command, SMC, Request message.

47. The method of claim 45, wherein the NAS message is sent after a Security Mode Command, SMC, procedure is completed with the UE.

48. The method of claim 43, wherein the correlation identifier is encrypted and/or integrity protected with a key.

49. The method of claim 48, wherein the key is any of: a Non-Access Stratum, NAS, key; a key derived from a NAS key; a Security Anchor Function, SEAF, key; and a key derived from a SEAF key.

50. A user equipment, UE, comprising a processor and a memory, said memory containing instructions executable by said processor whereby said UE is operative to perform the method of any of claims 1-21.

51. A network node comprising a processor and a memory, said memory containing instructions executable by said processor whereby said network node is operative to perform the method of any of claims 22-49.