Privacy indicator for controlling authentication requests

Abstract

Techniques are provided for providing privacy features in a communication system. For example, a message can be provided from a user equipment to an element or function in a communication network that includes one or more privacy indicators, where privacy features for processing the message are determined based on the privacy indicators. The message can include an attach request that includes a subscription identifier for a subscriber associated with the user equipment, where the privacy indicators include a flag that indicates whether the subscription identifier in the attach request is privacy protected. As another example, an element or function in the communication network can determine privacy features supported by the communication network, and generate and send a message to the user equipment that includes one or more privacy indicators selected based on the determined privacy features. The privacy indicators can include an indication of whether the communication network is configured to process privacy protected subscription identifiers.

Description

[0001] This application is a divisional application of application for Letters Patent No. 201880040462.2, filed December 17, 2019 (entitled “Privacy Indicator for Controlling Authentication Requests”), which is incorporated by reference herein in its entirety. TECHNICAL FIELD

[0002] The field relates generally to communication systems, and more specifically, but not exclusively, to security within such systems. BACKGROUND

[0003] This section introduces aspects that can be helpful in facilitating a better understanding of the aspects of the present application. Accordingly, the statements of this section are to be read in light of this objective and are not to be understood as an acknowledgment of what the prior art is or is not.

[0004] Fourth generation (4G) wireless mobile communication technologies (also referred to as Long Term Evolution (LTE) technologies) were designed to provide high capacity mobile multimedia, particularly for human interaction, with high data rates. The next generation or fifth generation (5G) technologies aim not only at human interaction but also at machine type communication in so-called Internet of Things (IoT) networks.

[0005] While 5G networks are intended to support large scale IoT services (e.g., very large numbers of capability limited devices) and critical machine type communications (e.g., requiring high reliability), improvements to traditional mobile communication services are supported in the form of enhanced mobile broadband (eMBB) services, which aim to provide improved wireless Internet access for mobile devices.

[0006] In an example communication system, user devices (5G UEs in a 5G network or more generally UEs) such as mobile terminals (subscribers) communicate over an air interface with base stations or access points (referred to as gNBs in a 5G network or eNBs (evolved Node Bs) in an LTE network). Illustratively, the access points (e.g., gNBs / eNBs) are part of an access network of the communication system. For example, in a 5G network, the access network is referred to as a 5G system and is described in the 5G Technical Specification (TS) entitled “Technical Specification Group Services and System Aspects; System Architecture for the 5G System,” the disclosure of which is incorporated by reference herein in its entirety. In an LTE network, the access network is the Evolved Universal Terrestrial Radio Access Network (E-UTRAN). Generally, the access points (e.g., gNBs / eNBs) provide the UEs with access to a core network (CN), which then provides the UEs with access to other UEs and or data networks, such as a packet data network (e.g., the Internet).

[0007] Privacy is an important consideration in any communication system. Privacy is extensively mentioned in the 5G Technical Report (TR) 33.899, entitled "3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Study on the security aspects of the next generation system (Release 14)," the disclosure of which is incorporated by reference herein in its entirety. In particular, TR 33.899 considers subscription (UE) privacy as one of the most important security areas to be addressed in 5G networks. SUMMARY

[0008] Illustrative embodiments provide for controlling one or more privacy indicators of an authentication request in a communication system.

[0009] For example, in one embodiment, a method includes receiving, at an element or function in a communication network, a message from a user equipment of the communication network, the message including one or more privacy indicators, and determining one or more privacy features for processing the message based on the one or more privacy indicators.

[0010] The message can include an attach request including a subscription identifier for a subscriber of the communication network associated with the user equipment, the one or more privacy indicators including a flag indicating whether the subscription identifier in the attach request is privacy protected. The privacy protected subscription identifier can include at least a portion of a permanent subscription identifier of the subscriber.

[0011] In another embodiment, a method includes determining, at an element or function in a communication network, one or more privacy features supported by the communication network, generating, at the element or function in the communication network, a message including one or more privacy indicators selected based on the determined one or more privacy features, and sending, from the element or function in the communication network, the generated message including the one or more privacy indicators to a user equipment of the communication network.

[0012] The one or more privacy features can include a capability of the element or function in the communication network to process a privacy protected subscription identifier.

[0013] In another embodiment, a method includes determining, at a user equipment of a communication network, one or more privacy features for processing a message; adding one or more privacy indicators to the message based on the determined one or more privacy features; and sending the message with the one or more privacy indicators from the user equipment to an element or function in the communication network.

[0014] The message can include an attach request that includes a subscription identifier for a subscriber of the communication network associated with the user equipment, the one or more privacy indicators including a flag indicating whether the subscription identifier in the attach request is privacy protected.

[0015] In another embodiment, a method includes receiving, at a user equipment of a communication network, a message including one or more privacy indicators from an element or function of the communication network; and utilizing the one or more privacy indicators to determine one or more privacy features supported by the communication network.

[0016] The one or more privacy indicators can include an indication of whether the communication network is configured for processing privacy protected subscription identifiers. The method can further include refraining from sending an attach request to the element or function in the communication network in response to the one or more privacy indicators indicating that the communication network is not configured for processing privacy protected subscription identifiers.

[0017] While these and other techniques described herein can be applied to a variety of communication networks, they are particularly applicable to 5G and next generation communication networks.

[0018] These and other features and advantages of the embodiments described herein will be apparent from the accompanying drawings and from the detailed specific description. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A communication system in an illustrative embodiment is shown.

[0020] Figure 2 A more detailed view of a server location function and a home subscriber server in an illustrative embodiment is shown.

[0021] Figure 3 A message flow for a user equipment authentication procedure for a LTE network in an illustrative embodiment is shown.

[0022] Figure 4 A message flow for a user equipment authentication procedure for a 5G network in an illustrative embodiment is shown.

[0023] Figure 5 A message flow for a user equipment authentication procedure for a hybrid LTE / 5G network in an illustrative embodiment is shown.

[0024] Figure 6 A message flow for a user equipment authentication procedure for a 5G network in another illustrative embodiment is shown.

[0025] Figure 7 A message flow for a user accessing a 5G network via non-3GPP access in an illustrative embodiment is shown. DETAILED DESCRIPTION

[0026] Embodiments will be explained herein in connection with an example communication system and associated techniques for managing authentication requests in a manner that protects the privacy of a user's subscription identity. It should be understood, however, that the scope of the claims is not limited to the particular type of communication system and / or procedures disclosed. Embodiments can be implemented in various other types of communication systems using alternative procedures and operations. For example, although explained in the context of a wireless cellular system that utilizes 3GPP system elements such as the LTE Evolved Packet Core (EPC) and the 3GPP Next Generation System (5G), the disclosed embodiments can be adapted in a straightforward manner to various other types of communication systems including, but not limited to, WiMAX systems and Wi-Fi systems.

[0027] As noted above, the privacy of a subscription identifier has been an important issue for 2G / 3G / 4G networks when communicating over the air interface between a user equipment and a network access point. In order to address this important issue, efforts have been made in 5G networks. Even though down bidding attacks (e.g., an attacker impersonating a user equipment to negotiate a poor security capability with a network access point) can be unavoidable that force a 5G UE to attach to a lower generation network, it must be recognized that these privacy needs need to be addressed.

[0028] The above cited TR 33.899 describes several solutions to provide privacy over the air interface that can generally be grouped into three solution categories:

[0029] 1) a pseudonym solution based on a symmetric cipher system that requires a home subscriber server / function of a home network of the UE to map a varying pseudonym to a permanent subscription identifier of the UE;

[0030] 2) encryption of the permanent subscription identifier of the UE using a public key of a home network operator; and

[0031] 3) encryption of the permanent subscription identifier of the UE using a public key of a serving network operator.

[0032] Note that in one example, the International Mobile Subscriber Identity (IMSI) is the permanent subscription identifier (subscriber identity) of the UE. In one embodiment, the IMSI is fixed 15 digit length and consists of a 3 digit Mobile Country Code (MCC), a 3 digit Mobile Network Code (MNC), and a 9 digit Mobile Station Identification Number.

[0033] Also note that in LTE networks, the home subscriber server / function is referred to as the Home Subscriber Server (HSS), and in 5G networks, it is referred to as the User Data Management (UDM), which can also include the Authentication and Security Function (AUSF) and the Authentication Credential Repository and Processing Function (ARPF) as part of the UDM function.

[0034] While some illustrative embodiments are described herein from the perspective of the second category of solutions (i.e., the home network public key based solution), embodiments for the other two categories of solutions can also be implemented. See SA2 TS 23.502 and SA3 TR 33.899, the disclosures of which are incorporated by reference herein in their entirety.

[0035] In the home network public key based solution, the home operator provides its public key to all home network subscribers. They will use this public key to encrypt the user identity, which is the MSIN part of the IMSI, for example. Only the MSIN part needs to be encrypted, as the serving network needs the MNC+MCC to route to the correct home network. The home HSS can only decrypt the message as it has the private key corresponding to the public key. Once the IMSI is identified, the HSS / AuC (where the AuC is the authentication center part of the HSS) will create an authentication vector (AV) based on different shared root keys K between the user (subscriber) and the HSS / AuC. Similarly, in 5G networks, the UDM / ARPF creates the AV requested via the AUSF. For optimization reasons, the AUSF and UDM can be co-located.

[0036] The operator can have multiple HSS implementations in his network, which allows him to manage different groups of users in different HSSs / UDMs. As there are multiple HSSs, a Server Location Function (SLF) can be implemented in front of a group of HSSs. Note that the SLF can also be referred to as a Subscriber Location Function. The SLF analyzes the authentication request of a user received from the MME / AMF and routes it to the correct HSS.

[0037] By way of example only, the operation of an SLF is described in 3GPP TS 29.272, entitled "3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; Evolved Packet System (EPS); Mobility Management Entity (MME) and Serving GPRS Support Node (SGSN) related interfaces based on Diameter protocol (Release 14)," Section 8: "User identity to HSS resolution," the disclosure of which is incorporated by reference herein in its entirety. The SLF provides user identity (IMSI) to HSS resolution using a locally maintained subscriber profile database and routes Diameter messages containing user authentication requests to a selected HSS as a Diameter proxy. Note that in 5G, if the 5G core network protocol is different from Diameter, similar functionality will also be requested, e.g., using an http proxy. In the following description, it is assumed that the SLF covers both the Diameter-based routing agent (DRA) solution according to 4G and any other proxy-related solution depending on the protocol decision for the 5G core network.

[0038] In this context, it is recognized that if the home operator uses an SLF to split its subscriber group, the SLF will need to evaluate the received identifier first. Thus, in a 5G network with a permanent subscriber identity (e.g., IMSI) encrypted by one of several methods, the SLF will need to take over the decryption of the MSIN part of the IMSI. Further, the SLF needs to maintain a database of profiles of all subscribers with routing information, i.e., the profile should map the permanent identity (e.g., IMSI) of a subscriber to one of the HSSs in the network to forward the authentication request after decryption of the received (encrypted) IMSI. Thus, it is advantageous to perform the decryption of the encrypted IMSI at the SLF instead of in the HSS. Thus, instead of the HSS storing the private key, the SLF now needs to store and use the network private key. The SLF is placed in the home operator's domain and is considered to be trusted. Typically, it can be assumed that the SLF is in a large operator network. The use of the SLF simplifies the new privacy management for the HSS / UDM in 5G networks, up to the point that the HSS / UDM does not change at all to protect the subscription identifier on the air interface, but the SLF needs to perform the additional functionality of encrypted IMSI decryption and then perform the IMSI to HSS resolution.

[0039] Accordingly, the illustrative embodiments described herein address the problem of how the HSS / UDM or SLF can efficiently handle the newly introduced privacy feature, i.e., the received attach request needs to be decrypted first. If this problem is not addressed, the HSS / UDM or SLF will receive the request and try to process it, wasting unnecessary computing resources.

[0040] The privacy will depend on country-specific rules, thus, the HSS / UDM or SLF needs to be implemented to handle two cases of requests for authentication vectors, i.e., to process or forward a "normal" attach request (if the 5G UE does not apply privacy) or to process a "privacy" attach request.

[0041] In a first illustrative embodiment, if the 5G UE wants to protect its privacy, it adds an identity privacy flag (i.e., privacy indicator) to indicate that the MSIN is provided in encrypted form.

[0042] It is to be understood that in addition to being an "explicit" privacy indicator (such as a flag or field), the privacy indicator can alternatively be an "implicit" privacy indicator. An implicit privacy indicator refers to the privacy feature being conveyed to the network element / function by the UE via the algorithm used to encrypt the message. Thus, by the fact that the message is encrypted with a particular encryption algorithm, the network element / function receiving the message from the UE is informed of the privacy feature. This also applies to the null encryption scheme. In the null encryption scheme, the input is equal to the output and the SUPI (Subscription Permanent Identifier of the UE) is unencrypted, i.e. a format preserving scheme. It can be understood this way that the SUPI (or IMSI) is always encrypted, but if no privacy is "turned on", null encryption is used. Thus, the privacy indicator would implicitly reside in the algorithm scheme used (e.g. null encryption or an algorithm that actually encrypts the message).

[0043] It can be suggested that even without such a privacy indicator, the HSS or SLF would calculate after the first attempt to resolve the request and if encryption was done, attempt decryption. However, the key reason for having such an indication specified is that this saves processing time and requires less resources. Thus, in this first illustrative embodiment, the SLF makes a decision on the processing by looking at this flag. If the flag is not set, the SLF assumes that the provided IMSI is unencrypted, the IMSI to HSS resolution will be done and the authentication request will be forwarded to the correct HSS / UDM, i.e. compatibility with 4G operation is maintained. If the flag is set, the SLF will recognize that the provided IMSI is encrypted and using the network private key, the MSIN part is decrypted to form the real unencrypted IMSI, the IMSI to HSS resolution is performed and then the authentication request is forwarded to the correct HSS / UDM. If no SLF is used, the HSS / UDM can use the same principle. That is, the HSS / UDM has to check if the 5G UE has set the flag and then decide if decryption needs to be done.

[0044] This first illustrative embodiment can be applied to 5G UEs that attach to a 5G Core Network (CN) via a 5G RAN (Radio Access Network). However, as an emergency deployment scheme, 3GPP has identified that 5G UEs should attach to a 4G CN via a 5G RAN. If the UE sets the indicator, the 4G CN needs to be enhanced to understand the identity privacy flag or other privacy indicator.

[0045] From the network architecture point of view of the operator, with the evolution of 4G networks towards 5G, there is a need to support 4G and 5G access as well as core network for quite some time. This means that the current 4G HSS needs to be supported, while a new 5G HSS functionality to decrypt the encrypted MSIN is supported. According to embodiments, placing a SLF that is able to identify encrypted MSIN and decrypt it before routing the authentication request to the HSS helps to manage the coexistence of 4G and 5G in the operator network. It is advantageous to enhance the SLF to support the new identity 5G privacy feature rather than the HSS. If the HSS is enhanced, in a large network with multiple HSSs, all of them need to be updated and have the capability to decrypt the encrypted IMSI. Handling this case can be more cumbersome compared to addressing the problem in a single central node (e.g. SLF). Advantageously, in the case of the first illustrative embodiment, if the same feature is also deployed in 4G (by which the enhanced SLF is used to implement this feature), the hammering attack in 5G (to 4G) would be unfruitful.

[0046] In a second illustrative embodiment, another privacy identifier is provided that the operator can decide to add to e.g. network master information block (MIB) / system information block (SIB) broadcast to indicate to the 5G UE that the network will be able to handle privacy protected identifiers, e.g. a flag indicating that privacy is expected, can be handled or desired. Then, if this indicator is not sent, depending on the policy implemented / configured by the 5G UE, it is decided whether to attach to the network at all. The indicator on the 4G / 5G network side indicates the regulatory requirements per country / region, i.e. privacy is on / off. Note that while the UE is roaming in a visited network, the serving network needs to be adapted even if the UE authentication request from the visited network is forwarded to the home network (for which the identity privacy indicator has been described (first illustrative embodiment above)). The MME / SEAF (SEAF is the security anchor function) has to handle the enhanced initial attach message from the UE, form the UE authentication request message and route it to the home network for requesting the AV. If the subscription identifier is encrypted, the size of the message field for the encrypted IMSI can be different from the current 4G IMSI field (depending on the selected solution category).

[0047] Note that the access network can also indicate its availability and, if applicable, not to use its privacy. This information can be broadcast, e.g. as part of a SIB or other information block, or sent to each UE as an implicit request.

[0048] In a third illustrative embodiment, the UE is configured to manage a privacy indicator that can be set to prohibit 5G UEs from paging for IMSI paging. Thus, if a UE wants to attach to a network and the network requests its real identity, a privacy-configured 5G UE configured with such a privacy indicator will not answer.

[0049] Various network configurations can be employed to implement the privacy indicator in view of the above privacy indicator. Figures 1 to 7 Some of these network configurations are depicted. However, it is to be appreciated that embodiments are not limited to the network configurations described herein or hereafter. Figure 1 A communication system 100 is shown within which illustrative embodiments are implemented. It is to be appreciated that the elements shown in the communication system 100 are intended to represent the main functionality provided within the system, e.g., UE access functionality, mobility management functionality, serving gateway functionality, etc. As such, Figure 1 The blocks shown reference specific elements that provide the main functionality in LTE and 5G networks. However, other network elements can be used to implement some or all of the main functionality represented. Also, it is to be appreciated that not all of the functionality of LTE or 5G networks is depicted in Figure 1 Rather, functionality that is beneficial to explain the illustrative embodiments is depicted.

[0050] Accordingly, as shown, the communication system 100 includes a user equipment (UE) 102 that communicates with an access point (eNB / gNB) 104 via an air interface 103. The UE 102 can be a mobile station and such mobile stations can include, by way of example, a mobile phone, a computer, or any other type of communication device. In LTE-V2X implementations, one or more UEs can be deployed in a given vehicle. Thus, the term "user equipment" as used herein is intended to be broadly interpreted to encompass various different types of mobile stations, subscriber stations, or more generally communication devices, including examples such as a combination of a data card plugged into a laptop or other device (e.g., a vehicle). Such communication devices are also intended to encompass devices commonly referred to as access terminals.

[0051] In one embodiment, the UE 102 is comprised of a Universal Integrated Circuit Card (UICC) and a Mobile Equipment (ME). The UICC is the user-dependent part of the UE and contains at least one Universal Subscriber Identity Module (USIM) and the appropriate application software. The USIM securely stores an International Mobile Subscriber Identity (IMSI) number and its related key, which are used to identify and authenticate a subscriber to access a network. The ME is the user-dependent part of the UE and contains Terminal Equipment (TE) functionality and various Mobile Termination (MT) functionality.

[0052] The access points 104 are illustrative parts of the access network of the communication system 100. Such an access network can include, for example, an E-UTRAN or a 5G system (or hybrid) with multiple base stations and one or more associated radio network control functions. The base stations and radio network control functions can be logically separate entities, but in a given embodiment can be implemented in the same physical network element, such as, for example, a base station router or femto cellular access point.

[0053] In this illustrative embodiment, the access points 104 are operatively coupled to a mobility management function 106. In LTE networks, the function is typically implemented by a mobility management element (MME), while in 5G networks, the function is implemented by an access and mobility management function (AMF). While not explicitly shown, the SEAF can be implemented with an AME that connects the UE and the mobility management. As used herein, the mobility management function is an element or function in the CN part of the communication system that manages access and authentication operations with the UE, among other network operations (through the access points 104).

[0054] In this illustrative embodiment, the MME / AMF 106 is operatively coupled to an SLF 107. In the illustrative embodiment, the SLF 107 is configured as described above to respond to one or more privacy indicators set in messages received thereby. As described above, depending on the one or more privacy indicators, the SLF 107 can either decrypt the subscriber identity or simply forward the encrypted information to the appropriate home network of the UE 102. Thus, as shown, the SLF 107 is operatively coupled to a plurality of HSS / UDM 108-1, 108-2,... 108-N. These HSS / UDM represent the home networks of UEs that can be attached to the communication system 100. The SLF 107 is configured to provide UE information to the HSS / UDM 108.

[0055] The access points 104 are also operatively coupled to a serving gateway function 110 (e.g., a serving gateway (SGW) in LTE networks, and a session management function (SMF) in 5G networks), which is operatively coupled to a packet data network (PDN) gateway (PGW) 112. The PGW 112 is operatively coupled to a packet data network, such as the Internet 114. The MME / AMF 106 and SLF 107 can be considered part of the CN. The MME / AMF 106 and SLF 107 can also be part of the serving network. Further typical operations and functions of these network elements are not described here as they are not the focus of the illustrative embodiment and can be found in the appropriate 3GPP LTE or 5G literature.

[0056] It is to be understood that this particular arrangement of system elements is merely an example, and that in other embodiments, additional or alternative elements of other types and arrangements can be used to implement a communication system. For example, in other embodiments, the system 100 can include authentication elements, as well as other elements not explicitly described herein.

[0057] Accordingly, Figure 1 The arrangement is merely one example configuration of a wireless cellular system, and many alternative configurations of system elements can be used. For example, while Figure 1 Only a single UE, eNB / gNB, MME / AMF, SLF, SGW / SMF, and PGW element is shown in the embodiments, this is merely for simplicity and clarity of description. Of course, a given alternative embodiment can include a large number of such system elements, as well as additional or alternative elements of the type typically associated with conventional system implementations.

[0058] It is also noted that while Figure 1 While the system elements are shown as single functional blocks, the various sub-networks that make up the 5G network are divided into so-called network slices. A network slice (network partition) includes a series of functional sets (i.e., chains of functions) for each corresponding service type using network function virtualization (NFV) on a common physical infrastructure. For a given service (e.g., eMBB services, massive IoT services (e.g., V2X services), and mission-critical IoT services), a network slice is instantiated as needed. Thus, when an instance of a network slice or function is created, this network slice or function is instantiated. In some embodiments, this involves installing or enabling the network slice or function on one or more host devices of the underlying physical infrastructure. The UE 102 is configured to access one or more of these services via the eNB / gNB 104.

[0059] Figure 2 A more detailed view of the SLF 107 and one HSS / UDM 108 in the illustrative embodiment is shown. Figure 1 Each HSS / UDM 108 (108-1, 108-2,... 108-N) in the system 100 can be configured as shown. Figure 2 The SLF 107 includes a processor 200 coupled to a memory 202 and interface circuitry 204. The processor 200 of the SLF 107 includes an authentication processing module 210, which can be implemented at least in part in the form of software executed by the processor 200. The authentication processing module 210 performs authentication operations in connection with the processes described herein and illustrated in the later figures. The memory 202 of the SLF 107 includes an authentication storage module 212, which stores authentication and related data generated or otherwise used during authentication operations.

[0060] The HSS / UDM 108 includes a processor 220 coupled to a memory 222 and an interface circuitry 224. The processor 220 of the HSS / UDM 108 includes an authentication processing module 230, which can be implemented at least in part in the form of software executed by the processor 220. The authentication processing module 230 performs authentication operations in connection with the processes described later and herein. The memory 222 of the HSS / UDM 108 includes an authentication storage module 232 that stores authentication and related data generated or used during authentication operations.

[0061] The processors 200 and 220 of the respective SLF 107 and HSS / UDM 108 can include, for example, microprocessors, application specific integrated circuits (ASICs), digital signal processors (DSPs), or other types of processing devices, as well as portions or combinations of these elements.

[0062] The memories 202 and 222 of the respective SLF 107 and HSS / UDM 108 can be used to store one or more software programs executed by the respective processors 200 and 220 to implement at least some portions of the functionality described herein. For example, the authentication operations and other functionality described later and herein can be implemented in a straightforward manner using software code executed by the processors 200 and 220.

[0063] Accordingly, a given one of the memories 202 or 222 can be viewed as an example of what is more generally referred to herein as a computer program product or still more generally as a processor-readable storage medium having executable program code embodied therein. Other examples of processor-readable storage media can include, in any combination, magnetic or optical disks or other types of magnetic or optical media. Illustrative embodiments can include articles of manufacture that include such computer program products or other processor-readable storage media.

[0064] The memories 202 or 222 can more specifically include, for example, electronic random access memories (RAMs) such as static RAMs (SRAMs), dynamic RAMs (DRAMs), or other types of volatile or non-volatile electronic memories. The latter can include, for example, non-volatile memories such as flash memories, magnetic RAMs (MRAMs), phase change RAMs (PC-RAMs), or ferroelectric RAMs (FRAMs). The term "memory" as used herein is intended to be interpreted broadly and can additionally or alternatively encompass, for example, read only memories (ROMs), disk-based memories or other types of storage devices, as well as portions or combinations of these devices.

[0065] The interface circuitry 204 and 224 of the respective SLF 107 and HSS / UDM 108 illustratively include transceivers or other communication hardware or firmware that allow the associated system elements to communicate with each other in the manner described herein.

[0066] From Figure 2 As can be seen, the SLF 107 is configured for communication with the HSS / UDM 108 via its respective interface circuitry 204 and 224, and vice versa. Such communication involves the SLF 107 sending data to the HSS / UDM 108, and the HSS / UDM 108 sending data to the SLF 107. However, in alternative embodiments, other network elements can be operably coupled between the SLF and the HSS / UDM. The term "data" as used herein is intended to be broadly construed so as to encompass any type of information that can be sent between user equipment and a core network via base station elements, including but not limited to identity data, authentication data, control data, audio, video, multimedia, etc.

[0067] It will be appreciated, Figure 2 The particular arrangement of components shown is merely an example, and in other embodiments many alternative configurations can be used. For example, the user equipment and mobility management function can be configured to incorporate additional or alternative components and support other communication protocols.

[0068] Other system elements, such as the UE 102, eNB / gNB 104, MME / AMF 106, SGW / SMF 110, and PGW 112, can also be configured to include components such as processors, memories, and network interfaces, respectively. These elements need not be implemented on separate independent processing platforms, but instead can represent different functional parts of a single common processing platform, for example. Such a processing platform can additionally include at least portions of the eNB / gNB and associated wireless network control functions.

[0069] Figures 3 to 7 Message flows and network configurations are illustrated within which one or more of the above privacy indicators can be implemented. These message flows and network configurations are understood to be illustrative embodiments.

[0070] Figure 3 An advanced UE authentication procedure 300 in LTE using an unencrypted IMSI, SLF, and multiple HSSs is illustrated in accordance with one illustrative embodiment.

[0071] More specifically, Figure 3The UE 302, RAN 304, MME 306, SLF 308, HSS1 310-1, and HSS2 310-2 are shown. While only two HSSs are depicted, any number of HSSs can be implemented in accordance with the embodiments described herein. In Figure 3 Step 1 of the UE authentication procedure flow, the UE 302 sends an Attach Request (IMSI) to the MME 306 through the RAN 304. In step 2, the MME 306 then sends an Authentication Request (IMSI) to the SLF 308. In step 3, the SLF 308 selects a HSS based on IMSI mapping to the HSS. In step 4, the SLF 308 sends an Authentication Request (IMSI) to the selected HSS, which as shown is HSS1 310-1. Figure 3 In Figure 5 step 5, the HSS1 310-1 generates an authentication vector (AV) based on a root key. In step 6, the HSS1 310-1 sends an Authentication Response (AV) to the SLF 308, and in step 7, the SLF 308 sends the Authentication Response (AV) to the MME 306. The Authentication Response can include: a random challenge (RAND), an authentication token (AUTN), and a key set identifier (KSI). In step 9, the MME 306 sends an Attach Response to the UE 302 through the RAN 304.

[0072] Figure 4 A high level UE authentication procedure 400 in 5G using encrypted IMSI, SLF, and multiple UDMs is illustrated. According to one illustrative embodiment, performing IMSI decryption at the SLF instead of at the UDM helps to keep the core authentication functionality unchanged. As used herein, the acronym EAP refers to Extensible Authentication Protocol, and the acronym AKA refers to Authentication and Key Agreement.

[0073] More specifically, Figure 4 The UE 402, (R)AN 404, AMF 406, SLF 408, AUSF / UDM 410-1, and AUSF / UDM 410-2 are shown. While only two AUSF / UDMs are depicted, any number of AUSF / UDMs can be implemented in accordance with the embodiments described herein. In Figure 4In step 1 of the UE authentication process flow, UE 402 sends a registration request (encrypted IMSI) to AMF 406 via (R)AN 404. Note that by referring to the encrypted IMSI, this can refer to the normally encrypted portion of the IMSI, such as the MSIN, or all or other parts of the IMSI. In step 2, AMF 406 sends the authentication request (encrypted IMSI) to SLF 408. Step 3 includes sub-steps 3a and 3b. In step 3a, SLF 408 decrypts the encrypted IMSI. In one embodiment, SLF 408 decrypts the encrypted IMSI using a specified certificate. In step 3b, SLF 408 selects an HSS based on the IMSI mapping to a UDM. In step 4, SLF 408 sends the authentication request (IMSI) to the selected UDM, such as... Figure 4 As shown, this UDM is UDM410-1. In Figure 5 In step 6, UDM 410-1 generates an authentication vector (AV) based on the root key. In step 7, AUSF / UDM 410-1 initiates EAP AKA' authentication or EAP AKA* authentication (AKA* refers to an AKA with added home control). In step 8, AUSF / UDM 410-1 sends the authentication response (AV) to SLF 408, and in step 9, SLF 408 sends the authentication response (AV) to AMF 406. In step 9, AMF 406 sends the authentication request to UE 402 via (R)AN 404.

[0074] Figure 5 The illustration depicts process 500 for a hybrid core architecture of UDM and HSS supporting 4G LTE and 5G networks, according to an illustrative embodiment. IMSI decryption at the SLF facilitates the management of the two cores.

[0075] More specifically, Figure 5 UE 502, gNB 504, AMF / MME 506, SLF 508, AUSF / UDM 510-1 and 510-2, and HSS 512 are shown. Although only two AUSF / UDMs are depicted, any number of AUSF / UDMs can be implemented according to the embodiments described herein.

[0076] exist Figure 5In step 1 of the process, the UE 502 sends an Attach Request (encrypted IMSI) to the AMF / MME 506 through the gNB 504. Note that by reference to encrypted IMSI, this can mean the portion of the IMSI that is typically encrypted, e.g., the MSIN, or all or other portions of the IMSI. In step 2, the AMF / MME 506 then sends an Authentication Request (encrypted IMSI) to the SLF 508. Step 3 includes sub-steps 3a and 3b. In step 3a, the SLF 508 decrypts the encrypted IMSI. In one embodiment, the SLF 508 decrypts the encrypted IMSI using a prescribed credential. In step 3b, the SLF 508 selects a HSS based on IMSI mapping to the HSS. In step 4, the SLF 508 sends an Authentication Request (IMSI) to the selected HSS, HSS 512, through AUSF / UDM 510-1 and 510-2. In Figure 5 In step 6, the HSS 512 sends an Authentication Response (AV) to the SLF 508 through AUSF / UDM 510-1 and 510-2, and in step 7, the SLF 508 sends the Authentication Response (AV) to the AMF / MME 506. In step 8, the AMF / MME 506 sends an Attach Response to the UE 502 through the gNB 504.

[0077] Figure 6 Figure illustrates an advanced UE authentication procedure 600 in 5G using an encrypted IMSI, SLF, and multiple HSSs, according to an illustrative embodiment. Performing IMSI decryption at the SLF instead of at the UDM helps to keep the core authentication functionality unchanged.

[0078] More specifically, Figure 6 A UE 602, (R)AN 604, AMF 606, AUSF 608, SLF 610, and UDMs 612-1 and 612-2 are shown. While only two UDMs are depicted, any number of UDMs can be implemented in accordance with the embodiments described herein. In Figure 6In step 1 of the high-level UE authentication procedure flow, UE 602 sends a registration request (encrypted IMSI) to AMF 606 through (R)AN 604. Note that by reference to encrypted IMSI, this can mean the portion of the IMSI that is typically encrypted, e.g., the MSIN, or all or other portions of the IMSI. In step 2, AMF 606 then sends an authentication request (encrypted IMSI) to AUSF 608. In step 3, AUSF 608 sends an authentication request (encrypted IMSI) to SLF 610. In step 3a, SLF 610 decrypts the encrypted IMSI. In one embodiment, SLF 610 decrypts the encrypted IMSI using a provisioned certificate. In step 3b, SLF 610 selects an HSS based on IMSI mapping to UDM. In step 4, SLF 610 sends an authentication request (IMSI) to the selected UDM, which is UDM 612-1 as shown, and in step 5, UDM 612-1 generates an authentication vector (AV) based on the root key. In step 6, UDM 612-1 sends an authentication response (AV) to SLF 610, and in step 7, SLF 610 sends an authentication response (AV) to AUSF 608. In step 8, AUSF 608 initiates EAP AKA' authentication or EAP AKA* authentication. In step 9, AUSF 608 sends an authentication response to AMF 606. In step 10, AMF 606 sends an authentication request to UE 602 through (R)AN 604. Figure 6 Figure 5 In step 1 of the high-level UE authentication procedure flow, UE 602 sends a registration request (encrypted IMSI) to AMF 606 through (R)AN 604. Note that by reference to encrypted IMSI, this can mean the portion of the IMSI that is typically encrypted, e.g., the MSIN, or all or other portions of the IMSI. In step 2, AMF 606 then sends an authentication request (encrypted IMSI) to AUSF 608. In step 3, AUSF 608 sends an authentication request (encrypted IMSI) to SLF 610. In step 3a, SLF 610 decrypts the encrypted IMSI. In one embodiment, SLF 610 decrypts the encrypted IMSI using a provisioned certificate. In step 3b, SLF 610 selects an HSS based on IMSI mapping to UDM. In step 4, SLF 610 sends an authentication request (IMSI) to the selected UDM, which is UDM 612-1 as shown, and in step 5, UDM 612-1 generates an authentication vector (AV) based on the root key. In step 6, UDM 612-1 sends an authentication response (AV) to SLF 610, and in step 7, SLF 610 sends an authentication response (AV) to AUSF 608. In step 8, AUSF 608 initiates EAP AKA' authentication or EAP AKA* authentication. In step 9, AUSF 608 sends an authentication response to AMF 606. In step 10, AMF 606 sends an authentication request to UE 602 through (R)AN 604.

[0079] Figure 7 Figure 7 illustrates a procedure 700 for a UE to access a 5G network via non-3GPP access (WLAN) and authentication, according to an illustrative embodiment. As used herein, the abbreviation AN refers to access network, the abbreviation NAI refers to network access identifier, and the abbreviation SUPI refers to a UE's serialized unique product identifier.

[0080] More specifically, Figure 7 A UE 702, non-3GPP AN 704, AMF 706, AUSF 708, and UDM 710 are shown. In Figure 7 ​In step 1 of the procedure, the UE 702 sends a registration request to the AMF 706 over the non-3GPP AN 704. In step 2, the AMF 706 sends an authentication request (NAI, [EAP]) to the AUSF 708. The AUSF 708 decides the authentication type (e.g., EAP AKA’ authentication or EAP AKA* authentication) and acts as an EAP server and performs the EAP AKA’ authentication or EAP AKA* authentication. In step 3, the security material is retrieved from the UDM 710 based on the NAI. In step 4, the AUSF 708 sends an authentication response ([EAP]) to the AMF 706, which initiates the UE authentication in step 5. As shown, during the UE authentication, the AMF 706 sends an authentication request (SUPI, [EAP]) to the AUSF 708. Several authentication request messages can be needed between the UE 702 and the AUSF 708 (via the AMF 706) depending on the selected EAP authentication method. When the UE authentication is successful, the AUSF 708 sends an authentication response ([EAP], keys) to the AMF 706. The keys are what can be used by the AMF 706 to generate non-access stratum (NAS), control plane (CP), and user plane (UP) specific security keys.

[0081] The technology discussed herein provides for controlling one or more privacy indicators for authentication requests in a communication system. For example, such privacy indicators can be controlled (e.g., set) using one or more bits in an information element or flag sent to elements of the communication system. Further, methods and mechanisms are provided for resolving how a home network of a user equipment and other elements / functions in a core network (e.g., a server location function) effectively handle the one or more privacy indicators. Advantageously, the one or more privacy indicators conserve wasted computing resources in implementing them in one or more network configurations.

[0082] It is to be appreciated that the nomenclature of identifiers mentioned herein, e.g., IMSI, etc., is for illustration only. That is, identifiers of UEs can have different names or abbreviations in different protocols and standards used for different communication network technologies. Accordingly, the specific names or abbreviations given to such identifiers herein are not intended to limit the embodiments in any way.

[0083] As previously mentioned, embodiments are not limited to the LTE or 5G context, and the disclosed technology can be adapted in a straightforward manner to various other communication system contexts, including but not limited to other 3GPP systems and non-3GPP systems that employ identities (e.g., IMSIs or equivalents) in identity request procedures.

[0084] The processors, memories, controllers, and other components of the user equipment or base station elements of the communication systems disclosed herein can include known circuitry that is suitably modified to implement at least a portion of the identity request functionality described above.

[0085] As described above, embodiments can be implemented in the form of articles of manufacture comprising one or more software programs executed by processing circuitry of user equipment, base stations, or other elements of a communication system. Conventional aspects of such circuitry are well known to those skilled in the art, and therefore will not be described in detail herein. Similarly, embodiments can be implemented in any combination of one or more ASICs, FPGAs, or other types of integrated circuit devices. Such integrated circuit devices, as well as portions or combinations of them, are examples of the term "circuitry" as used herein. Various other arrangements of hardware and associated software or firmware can be used in implementing the illustrative embodiments.

[0086] Thus, it should again be emphasized that the various embodiments described herein are presented by way of illustrative example only, and are not intended to limit the scope of the claims. Alternative embodiments within the scope of the claims can employ different communication system configurations, user equipment configurations, base station configurations, identity request procedures, messaging protocols, and message formats than those described above, for example. These and numerous other alternative embodiments within the scope of the accompanying claims will be apparent to those skilled in the art.

Claims

1. A method for communication, comprising: A broadcast message is generated at a first element in the communication network, the broadcast message including a System Information Block (SIB) or Master Information Block (MIB) indicating whether the communication network is configured to process privacy-preserving subscription identifiers; The generated broadcast message is sent from the first element in the communication network to the user equipment of the communication network. At a second element in the communication network, a registration request message is received from a user equipment of the communication network. The registration request message includes one or more privacy indicators and a request, wherein the request includes a privacy-protected subscription identifier for a subscriber associated with the user equipment, and the one or more privacy indicators include a field indicating whether the subscription identifier in the request is privacy-protected. Based on the field, determine whether the subscription identifier in the request is privacy-protected; If it is determined from the fields of the one or more privacy indicators that the subscription identifier in the request is privacy-protected, remove the privacy protection from the subscription identifier in the request; and The second element in the communication network includes a Server Location Function (SLF) that uses the subscription identifier to map the request to a Home Subscriber Server (HSS) or a User Data Management (UDM) function.

2. A method for communication, comprising: At a user equipment in a communication network, a broadcast message is received from a first element in the communication network, the broadcast message including a System Information Block (SIB) or Master Information Block (MIB) indicating whether the communication network is configured to process privacy-preserving subscription identifiers. A request message is generated at the user equipment, the request message including a registration request and a subscription identifier for the subscriber associated with the user equipment; If the SIB or MIB in the broadcast message received from the first element of the communication network indicates that the communication network is configured to process privacy-preserving subscription identifiers, the subscription identifier in the request message is privacy-preserving, and one or more second privacy indicators including a second field are added to the request message, the second field indicating that the subscription identifier in the request is privacy-preserving; as well as The user equipment sends the request message, which includes the privacy-protected subscription identifier, to a second element in the communication network.

3. The method according to claim 2, further comprising: At the user equipment, it is determined based on the SIB or MIB that the communication network is not configured to handle privacy-preserving subscription identifiers; Add the subscription identifier to the message including the attach request at the user equipment; as well as The message is sent from the user equipment to a third element in the communication network.

4. The method of claim 2 or 3, wherein the broadcast message includes a first privacy indicator indicating whether the communication network is configured to process privacy-preserving subscription identifiers.

5. The method of claim 4, wherein the first privacy indicator includes a first field indicating whether the communication network is configured to handle privacy-preserving subscription identifiers.

6. The method according to any one of claims 2-5, wherein the subscription identifier is a privacy-preserving subscription identifier, and the subscription identifier includes at least a portion of the subscriber's permanent subscription identifier.

7. The method according to any one of claims 2-6, wherein the subscription identifier is protected for privacy using the public key of the subscriber's home network operator.

8. The method according to any one of claims 2-7, wherein the element in the communication network includes a Server Location Function (SLF) that uses the subscription identifier to map the request to a Home Subscriber Server (HSS) or a User Data Management (UDM) function.

9. The method according to any one of claims 2-8, wherein the communication network includes a fifth-generation 5G system.

10. A user equipment for communicating in a communication network, the user equipment including a processor operatively coupled to a memory and configured to perform: At the user equipment, a broadcast message is received from a first element in the communication network, the broadcast message including a System Information Block (SIB) or Master Information Block (MIB) indicating whether the communication network is configured to process privacy-preserving subscription identifiers. A request message is generated at the user equipment, the request message including a subscription identifier for a subscriber associated with the user equipment; If the SIB or MIB in the broadcast message received from the first element of the communication network indicates that the communication network is configured to process privacy-preserving subscription identifiers, the subscription identifier in the request message is privacy-preserving, and one or more second privacy indicators including a second field are added to the request message, the second field indicating that the subscription identifier in the request is privacy-preserving; as well as The user equipment sends the request message, which includes the privacy-protected subscription identifier, to a second element in the communication network.

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