Communication method and apparatus

Abstract

A communication method and apparatus. The method comprises: a MAC PDU sent to an access network comprising a first MAC SDU and N information units, wherein the first MAC SDU comprises a message 3 in a random access procedure. Because the N information units are encrypted by using a first key determined on the basis of a first AS security context of a terminal device, the security of the N information units sent along with the message 3 can be improved. Because MAC-I corresponding to the message 3 is determined on the basis of the N information units, integrity protection for the message 3 is implemented on the basis of the N information units, security protection for MAC layer information is implemented, and system security is improved.

Description

A communication method and apparatus

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410916869.4, filed on July 9, 2024, entitled "A Communication Method and Apparatus", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of communication technology, and in particular to a communication method and apparatus. Background Technology

[0004] In wireless communication, communication security is a crucial factor, involving the protection of user data. To ensure secure communication between base stations and terminals, the base station can initiate a secure mode after the terminal device initially connects, sending parameters such as an encryption key and an integrity protection key to the terminal device. Subsequent signaling interactions between the base station and the terminal device can encrypt transmitted data based on the encryption key and provide air interface integrity protection based on the integrity protection key.

[0005] However, currently, before the base station sends the encryption key and integrity protection key to the terminal device, the signaling exchanged between the base station and the terminal device is not encrypted or protected for integrity. This could lead to the leakage or tampering of user data. For example, before a secure mode is activated between the base station and the terminal device, a fake base station can obtain and modify the signaling exchanged between them. Therefore, improving system security is an urgent problem to be solved. Summary of the Invention

[0006] This application provides a communication method and apparatus to improve system security.

[0007] Firstly, this application provides a communication method, wherein the execution subject of the method is a terminal device or a module or chip within the terminal device, and the method is described here using a terminal device as an example. The method includes: generating a Media Access Control (MAC) Protocol Data Unit (PDU); the MAC PDU includes a first MAC Service Data Unit (SDU) and N information units, wherein the information units are MAC SDUs or MAC Control Elements (CEs), and N is an integer greater than 0; the first MAC SDU includes message 3 from the random access process; wherein the N information units are encrypted using a first key, which is determined based on the first access layer (AS) security context of the terminal device; or the message integrity authentication code (MAC-I) corresponding to message 3 is determined based on the N information units; the terminal device is in a radio resource control (RRR) inactive state; and the MAC PDU is sent to the access network device.

[0008] This method encrypts N information units using a first key determined by the first AS security context of the terminal device, thereby improving the security of the N information units sent along with message 3, enhancing information security during random access, and improving system security. The MAC-I corresponding to message 3 is determined based on the N information units, enabling integrity protection of message 3 based on these N information units, achieving secure protection of MAC layer information, and improving system security.

[0009] In one possible implementation, the integrity protection key used to determine the MAC-I is a first key.

[0010] By using the first key as the integrity protection key to generate the MAC-I, the security of the MAC PDU can be further improved, and the security protection of MAC layer information can be achieved.

[0011] In one possible implementation, the message integrity authentication code MAC-I corresponding to message 3 is determined based on the N information units, including: the MAC-I corresponding to message 3 is determined based on at least one of the following: a hash value determined based on at least one of the N information units; a first value, the first value being determined based on the M logical channel identifiers (LCIDs) corresponding to the M information units among the N information units, where M is an integer less than or equal to N.

[0012] The MAC-I determined by the above method is related to N information units. Therefore, when the N information units are tampered with, the receiving end will be unable to verify the MAC-I corresponding to message 3, which can further improve the security of the MAC PDU and realize the security protection of MAC layer information.

[0013] In one possible implementation, the first value is the sum of the M LCIDs; or, the first value is a hash value determined based on the M LCIDs; or, the first value is a cyclic redundancy check value determined based on the M LCIDs.

[0014] In one possible implementation, before generating the Media Access Control (MAC) Protocol Data Unit (PDU), the method further includes: receiving first information from the access network device, wherein the first information indicates that information during the random access process should be encrypted and / or protected for integrity.

[0015] In one possible implementation, the method further includes: receiving second information from the access network device, the second information indicating a notification area RNA list or cell list based on the radio access network, wherein the area corresponding to the RNA list or cell list is an area for encrypting and / or protecting the integrity of information during the random access process.

[0016] In one possible implementation, the cell where the terminal device is located is located in the RNA list or cell list.

[0017] In one possible implementation, the MAC-I is further determined based on Channel State Information (CSI).

[0018] This method uses CSI as the input parameter for MAC-I. Since CSI is generated by the terminal device itself, the security of the MAC PDU can be further improved, thus achieving secure protection of MAC layer information.

[0019] In one possible implementation, before sending the MAC PDU to the access network device, the method further includes sending a random access request message to the access network device.

[0020] In one possible implementation, the LCID of the first MAC SDU is the index of the Common Control Channel (CCCH).

[0021] Secondly, this application provides a communication method, wherein the execution subject of the method is an access network device or a module or chip within the access network device, and the method is described here using an access network device as an example. The method includes: receiving a Media Access Control (MAC) Protocol Data Unit (PDU) from a terminal device; the MAC PDU includes a first MAC Service Data Unit (SDU) and N information units, wherein the information units are MAC SDUs or MAC Control Elements (CEs), the first MAC SDU includes a message 3 in the random access process, and N is an integer greater than 0; wherein the N information units are encrypted using a first key, the first key being determined based on the first access layer (AS) security context of the terminal device; or the message integrity authentication code (MAC-I) corresponding to the message 3 is determined based on the N information units; the terminal device is in a radio resource control (RRR) inactive state; decrypting the N information units, or verifying the MAC-I based on the N information units.

[0022] In one possible implementation, message 3 includes a first identifier of the terminal device; the decryption of the N information units includes:

[0023] The second AS security context of the terminal device is determined based on the first identifier, and the second key is determined based on the second AS security context; the N information units are decrypted based on the second key.

[0024] In one possible implementation, verifying the MAC-I based on the N information units includes: determining the expected message integrity authentication code XMAC-I based on the N information units; if the XMAC-I is the same as the MAC-I, then the MAC-I verification passes; or, if the XMAC-I is not the same as the MAC-I, then the MAC-I verification fails.

[0025] In one possible implementation, the integrity protection key used to determine the MAC-I is the first key.

[0026] In one possible implementation, the message integrity authentication code MAC-I corresponding to message 3 is determined based on the N information units, including: the MAC-I corresponding to message 3 is determined based on at least one of the following: a hash value determined based on at least one of the N information units; a first value, the first value being determined based on the M logical channel identifiers (LCIDs) corresponding to the M information units among the N information units, where M is an integer less than or equal to N.

[0027] In one possible implementation, the first value is the sum of the M LCIDs; or, the first value is a hash value determined based on the M LCIDs; or, the first value is a cyclic redundancy check value determined based on the M LCIDs.

[0028] In one possible implementation, before generating the Media Access Control (MAC) Protocol Data Unit (PDU), the method further includes:

[0029] Send a first message, which instructs that information during the random access process be encrypted and / or protected for integrity.

[0030] In one possible implementation, the method further includes: sending a second message indicating a notification area RNA list or cell list based on the radio access network, wherein the area corresponding to the RNA list or cell list is an area for encrypting and / or protecting the integrity of information during the random access process.

[0031] In one possible implementation, the cell where the terminal device is located is located in the RNA list or cell list.

[0032] In one possible implementation, the MAC-I is further determined based on Channel State Information (CSI).

[0033] In one possible implementation, the method further includes: if the N information units are successfully decrypted, or if the MAC-I verification is determined to be successful based on the N information units, sending message 4 from the random access process to the terminal device; or if the N information units are decrypted but fail to be decrypted, or if the MAC-I verification is determined to be unsuccessful based on the N information units, releasing the radio resource control connection of the terminal device.

[0034] Thirdly, this application provides a communication method, the execution subject of which is a terminal device or a module or chip within the terminal device. Here, the terminal device is used as the execution subject for example. The method includes: generating a Media Access Control (MAC) Protocol Data Unit (PDU); the MAC PDU includes a first MAC Service Data Unit (SDU) and N information units, wherein the information units are MAC SDUs or MAC Control Elements (CEs), the first MAC SDU includes a message 3 from the random access procedure, and N is an integer greater than 0; wherein the N information units are encrypted and / or protected for integrity using a first key, the first key being determined based on the non-access stratum key of the terminal device; the terminal device is in a radio resource control idle state; and the MAC PDU is sent to the access network device.

[0035] This method encrypts N information units using a first key determined by the non-access stratum key of the terminal device, which can improve the security of the N information units sent along with message 3, enhance information security during random access, and improve system security.

[0036] In one possible implementation, the method further includes: receiving first indication information from the access network device, the first indication information indicating that information during the random access process should be encrypted and / or protected for integrity.

[0037] In one possible implementation, the method further includes: receiving second indication information, the second indication information indicating a core network device set or a tracking area corresponding to the core network device set, the tracking area corresponding to the core network device set being the effective area of ​​the first key.

[0038] In one possible implementation, message 3 includes a first identifier of the terminal device, which is determined based on the identifier of the core network device set.

[0039] In one possible implementation, the method further includes: sending a random access request message to the access network device, the random access request message being associated with an identifier of the core network device set.

[0040] Fourthly, this application provides a communication method, the execution subject of which is an access network device or a module or chip within the access network device. Here, the method is described using an access network device as the execution subject as an example. The method includes: receiving a MAC PDU from a terminal device; the MAC PDU includes a first MAC SDU and N information units, each information unit being a MAC SDU or MAC CE, the first MAC SDU including message 3 from a random access procedure, and N being an integer greater than 0; wherein the N information units are encrypted and / or protected for integrity using a first key, the first key being determined based on the non-access stratum key of the terminal device; the terminal device is in a radio resource control idle state; decrypting and / or verifying the integrity of the N information units; or sending the N information units to a core network device and receiving verification information from the core network device, the verification information indicating whether the decryption of the N information units was successful and / or whether the integrity verification of the N information units was passed.

[0041] In one possible implementation, message 3 includes a first identifier of the terminal device; the decryption and / or integrity verification of the N information units includes: sending the first identifier to the core network device and receiving a second key from the core network device, the second key being determined based on the non-access stratum key corresponding to the first identifier; decrypting the N information units based on the second key, and / or performing integrity verification on the N information units based on the second key.

[0042] In one possible implementation, the method further includes: sending a first indication message, the first indication message indicating that information during the random access process should be encrypted and / or protected for integrity.

[0043] In one possible implementation, the method further includes: sending second indication information, the second indication information indicating a core network device set or a tracking area corresponding to the core network device set, the tracking area corresponding to the core network device set being the effective area of ​​the first key.

[0044] In one possible implementation, message 3 includes a first identifier of the terminal device, which is determined based on the identifier of the core network device set.

[0045] Fifthly, this application provides a communication method, wherein the execution subject of the method is a core network device or a module or chip within the core network device, and the core network device is used as an example for description. The method includes: receiving a first identifier from an access network device, and N information units, wherein the information units are Media Access Control (MAC) Service Data Units (SDUs) or MAC Control Elements (CEs), and N is an integer greater than 0; wherein the N information units are encrypted and / or protected for integrity using a first key, the first key being determined based on a non-access stratum key; decrypting the N information units according to a second key, and / or performing integrity verification on the N information units according to the second key, the second key being determined based on the non-access stratum key corresponding to the first identifier; and sending verification information to the access network device, the verification information indicating whether decryption was successful and / or whether integrity verification was passed.

[0046] Sixthly, this application also provides a communication device capable of implementing any of the methods provided in any of the first to fifth aspects. This communication device can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the aforementioned functions.

[0047] In one possible implementation, the communication device includes a processor configured to support the communication device in performing corresponding functions of the access network device, terminal device, or core network device as described above. The communication device may also include a memory coupled to the processor, which stores necessary program instructions and data for the communication device. Optionally, the communication device further includes interface circuitry for supporting communication between the communication device and devices such as terminal devices.

[0048] In one possible implementation, the communication device includes corresponding functional modules, each used to implement the steps in the above method. The functions can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions described above.

[0049] In one possible implementation, the communication device includes a processing unit and a communication unit, which can perform the corresponding functions in the above method examples, as described in the methods provided in any of the first to fifth aspects, and will not be repeated here.

[0050] A seventh aspect provides a communication device, including a processor and an interface circuit. The interface circuit is used to receive signals from other communication devices outside the communication device and transmit them to the processor, or to send signals from the processor to other communication devices outside the communication device. The processor implements the functional modules of the methods in any possible implementation of any of the first to fifth aspects through logic circuits or by executing computer programs or instructions. Optionally, the communication device further includes a memory for storing computer programs or instructions.

[0051] Eighthly, a computer-readable storage medium is provided that stores a computer program or instructions which, when executed by a processor, implement the method in any possible implementation of any of the first to fifth aspects.

[0052] Ninthly, a computer program product storing instructions is provided, which, when read and executed by a computer, implements the method in any possible implementation of any of the first to fifth aspects.

[0053] In a tenth aspect, a circuit is provided for performing the methods in any possible implementation of any of the first to fifth aspects described above. The circuit may include a chip circuit. Optionally, the circuit may also be coupled to a memory.

[0054] Eleventhly, a chip is provided, comprising a processor, which, when executing a computer program or instructions, implements the methods in any possible implementation of any of the first to fifth aspects. Optionally, the chip may further include a memory, and the chip may be composed of chips or may include chips and other discrete devices.

[0055] In a twelfth aspect, a communication device is provided, including a processor that implements the methods in any possible implementation of any of the first to fifth aspects via logic circuits or by executing computer programs or instructions. Optionally, the communication device may further include a memory, which may be a computer program or instruction.

[0056] In a thirteenth aspect, a communication apparatus is provided, comprising a unit or module for performing a method in any possible implementation of any of the first to fifth aspects described above.

[0057] In a fourteenth aspect, embodiments of this application also provide a communication system. The communication system includes: a terminal device for implementing the methods of the first aspect and any possible implementations thereof; and an access network device for implementing the methods of the second aspect and any possible implementations thereof. Alternatively, the communication system includes: a terminal device for implementing the methods of the third aspect and any possible implementations thereof; and an access network device for implementing the methods of the fourth aspect and any possible implementations thereof. Attached Figure Description

[0058] Figure 1 is a schematic diagram of a base station architecture provided in an embodiment of this application;

[0059] Figure 2 is a schematic diagram of a network architecture applicable to an embodiment of this application;

[0060] Figure 3 is a schematic diagram of a fake base station provided in an embodiment of this application;

[0061] Figure 4 is a schematic diagram of a man-in-the-middle attack provided in an embodiment of this application;

[0062] Figure 5 is a schematic diagram of a network architecture applicable to an embodiment of this application;

[0063] Figure 6 is a schematic flowchart of a key generation method provided in an embodiment of this application;

[0064] Figure 7 is a schematic diagram of an air interface integrity protection process provided in an embodiment of this application;

[0065] Figure 8 is a schematic flowchart of a communication method provided in an embodiment of this application;

[0066] Figure 9 is a schematic diagram of a MAC PDU provided in an embodiment of this application;

[0067] Figure 10 is a schematic flowchart of a communication method provided in an embodiment of this application;

[0068] Figure 11 is a schematic flowchart of a communication method provided in an embodiment of this application;

[0069] Figure 12 is a schematic flowchart of a communication method provided in an embodiment of this application;

[0070] Figure 13 is a schematic flowchart of a communication method provided in an embodiment of this application;

[0071] Figure 14 is a schematic diagram of a communication device structure provided in an embodiment of this application;

[0072] Figure 15 is a schematic diagram of a communication device structure provided in an embodiment of this application;

[0073] Figure 16 is a schematic diagram of a communication device structure provided in an embodiment of this application. Detailed Implementation

[0074] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. The terms "first," "second," and corresponding terminology in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. The methods and apparatus provided in the embodiments of this application are based on the same or similar technical concepts. Since the principles by which the methods and apparatus solve problems are similar, the implementation of the apparatus and methods can refer to each other, and repeated details will not be repeated.

[0075] The technical solutions provided in the embodiments of this application can be applied to communication systems related to the 3rd Generation Partnership Project (3GPP), such as Long Term Evolution (LTE) communication systems, 5th Generation (5G) mobile communication systems, or to future communication systems or other similar communication systems. Furthermore, the technical solutions provided in the embodiments of this application can be applied to cellular links, public land mobile networks (PLMNs), machine-to-machine (M2M) networks, Internet of Things (IoT) networks, or other networks. They can also be applied to device-to-device links, such as device-to-device (D2D) links or sidelinks.

[0076] The following section will first explain some of the terms used in the embodiments of this application so that those skilled in the art can understand them.

[0077] In this embodiment, the access network device can be a device in a wireless network, or it can be called a network device or a wireless access network device. For example, the access network device can be a radio access network (RAN) node that connects terminal devices to the wireless network, and it can also be called an access network device. The access network device includes, but is not limited to: base station, evolved NodeB (eNodeB), transmission reception point (TRP), next-generation NodeB (gNB) in 5th generation (5G) mobile communication systems, access network devices in open radio access networks (O-RAN), base stations in future mobile communication systems, or access nodes in wireless fidelity (WiFi) systems; or it can be a module or unit that performs some functions of a base station, such as a central unit (CU), a distributed unit (DU), a central unit control plane (CU-CP) module, or a central unit user plane (CU-UP) module. Access network equipment can be macro base stations, micro base stations, indoor stations, relay nodes, or donor nodes, etc. This application does not limit the specific technologies or equipment forms used in the access network equipment.

[0078] In some implementations, access network equipment can include centralized units (CUs) and distributed units (DUs). This includes RAN equipment at CU and DU nodes that separate the protocol layers of the gNB in ​​the NR system. Some protocol layer functions are centrally controlled by the CU, while the remaining partial or complete protocol layer functions are distributed across the DUs, which are then centrally controlled by the CU. Furthermore, the CU can be divided into a control plane (CU-CP) and a user plane (CU-UP). The CU-CP handles control plane functions, primarily including radio resource control (RRC) and the corresponding packet data convergence protocol (PDCP) (PDCP-C). PDCP-C is mainly responsible for control plane data encryption / decryption, integrity protection, and data transmission. The CU-UP handles user plane functions, primarily including the service data adaptation protocol (SDAP) and the corresponding PDCP (PDCP-U). SDAP is mainly responsible for processing core network data and mapping flows to bearers. PDCP-U is primarily responsible for data plane encryption / decryption, integrity protection, header compression, sequence number maintenance, and data transmission. CU-CP and CU-UP are connected via the E1 interface. CU-CP represents the gNB connected to the core network via the NG interface and to the DU via the F1 interface control plane (F1-C). CU-UP is connected to the DU via the F1 interface user plane (F1-U). Alternatively, PDCP-C may also be located within CU-UP.

[0079] It is understood that CU (including CU-CP or CU-UP) or DU may have different names in different systems, but those skilled in the art will understand their meaning. For example, in an open radio access network (O-RAN) system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, and CU-UP can also be called O-CU-UP. For ease of description, this application uses CU, CU-CP, CU-UP, and DU as examples. The access network equipment may also include an active antenna unit (AAU). CU implements some of the functions of gNB, and DU implements some of the functions of gNB. For example, CU is responsible for handling non-real-time protocols and services, implementing the functions of the RRC layer. DU is responsible for handling physical layer protocols and real-time services, implementing the functions of the radio link control (RLC) layer, media access control (MAC) layer, and physical (PHY) layer. In some deployments, the CU can also be divided into a centralized unit control plane (CU-CP) node and a centralized unit user plane (CU-UP) node. The CU-CP is responsible for control plane functions, while the CU-UP is responsible for user plane functions.

[0080] For example, taking the access network device as a base station as an example, see Figure 1, which is a schematic diagram of two typical protocol stacks of the base station provided in the embodiments of this application. In the base station (1), the base station is divided into CU and DU. The CU is configured to implement the functions of the PDCP layer and above protocol layers (such as the RRC layer and / or SDAP layer, etc.); the DU is configured to implement the functions of the protocol layers below the PDCP layer (such as the RLC layer, MAC layer, and / or PHY layer, etc.). The CU and DU communicate with each other based on the F1 interface. In the base station (2), the base station is divided into CU and DU. The CU includes CU-CP and CU-UP. CU-CP is used to implement the control plane function of the CU, and CU-UP is used to implement the user plane function of the CU. CU-CP and CU-UP can communicate based on the E1 interface. CU-CP and DU communicate based on the F1 interface (also called F1-C) that supports the control plane. CU-UP and DU communicate based on the F1 interface (also called F1-U) that supports the user plane. CU-CP is configured to implement the control plane and RRC layer functions of the PDCP layer, and CU-UP is configured to implement the user plane and SDAP layer functions of the PDCP layer. DU is configured to implement the functions of protocol layers below the PDCP layer (such as RLC, MAC, and / or PHY layers).

[0081] The above division of CU and DU processing functions according to the protocol layer is merely an example; other division methods are also possible, and this application does not impose any restrictions.

[0082] The terminal device involved in the embodiments of this application can be a wireless terminal device capable of receiving scheduling and instruction information from network devices (e.g., access network devices). The terminal device can be referred to as a terminal device, or it can also be called user equipment (UE), terminal, mobile station (MS), mobile terminal (MT), etc. The terminal device can be a device that includes wireless communication functions (providing voice / data connectivity to the user). For example, a handheld device with wireless connectivity, or an in-vehicle device, in-vehicle module, etc. Currently, examples of terminal devices include: mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in vehicle-to-everything (V2X) communication, wireless terminals in vehicle-to-everything (V2X) communication, intelligent vehicles, in-vehicle infotainment systems (or onboard transmitters) (T-boxes), machine-to-machine / machine-type communications (M2M / MTC) terminal devices, and the Internet of Things (IoT). Wireless terminals in industrial control systems can include devices such as IoT (Internet of Things) terminals. For example, terminal devices can be in-vehicle equipment, vehicle-mounted modules, vehicles, on-board units (OBUs), roadside units (RSUs), T-boxes, chips, or systems-on-chips (SoCs), which can be installed in vehicles, OBUs, RSUs, or T-boxes. Wireless terminals in industrial control systems can be cameras, robots, etc. Wireless terminals in smart homes can be televisions, air conditioners, robot vacuums, speakers, set-top boxes, etc.Furthermore, in this embodiment, the terminal device can also be a terminal device in an IoT system. IoT is an important component of the future development of information technology. Its main technical feature is to connect objects to the network through communication technology, thereby realizing an intelligent network of human-machine interconnection and object-to-object interconnection.

[0083] This application also applies to O-RAN architecture. As shown in Figure 2, an O-RAN system may include access network equipment, terminal equipment, and core network equipment. An O-RAN system may include other components besides those shown in the figure. As shown in Figure 2, the access network equipment (e.g., an eNB, gNB, or next-generation access network equipment) communicates with the core network (CN) equipment via a backhaul link and with the user equipment (UE) via an air interface.

[0084] For example, the baseband unit (BBU) in the access network equipment can communicate with the core network via a backhaul link, while the radio unit (RU) in the access network equipment can communicate with at least one UE via an air interface. The BBU communicates with at least one RU via a fronthaul link. The BBU and RU may or may not be co-located.

[0085] A BBU includes at least one of a Control Unit (CU) and at least one Distributed Unit (DU), which can communicate via at least one midhaul link. In the ORAN system, the CU can also be called an open CU (O-CU), and the DU can also be called an open DU (O-DU).

[0086] In this application embodiment, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items; for example, at least one of a, b, or c can represent: a, b, c, a and b, a and c, b and c, or a, b, and c.

[0087] Fake base station attack: refers to network attackers placing illegal base stations within the coverage area of ​​the target base station. Fake base stations can force nearby target terminals to perform cell reselection, location updates, and cell handover, thereby deceiving the terminal or providing the terminal with incorrect information to achieve purposes such as spreading viruses or network fraud.

[0088] For example, as shown in Figure 3, a fake base station can consist of an engineering terminal (e.g., a computer / mobile phone), cables, and a wireless transceiver. By impersonating a mobile communication operator's base station, it deceives terminals and launches attacks. Fake base station attacks can forge system messages, which overwrite genuine system messages in the network, causing the target terminal to reject the target base station's services. Additionally, fake base stations can trick terminals into initiating network registration or location update requests, attracting the target terminal to reside on the fake base station and extracting its information. At this point, the terminal is disconnected from the normal network and unable to obtain network services. Fake base stations can also transmit information with terminals, such as sending fraudulent text messages, malicious network links, or harassing text messages.

[0089] Fake base stations can also intercept communication data between the target base station and the terminal, thereby monitoring users' private data. While launching deceptive attacks on terminals, fake base stations also interfere with normal communication between the network and the terminal, impacting network performance.

[0090] Man-in-the-middle attack: refers to a fake base station combined with a fake terminal relaying encrypted data between the terminal and the network, and tampering with the data to carry out the attack when there is no integrity protection.

[0091] For example, as shown in Figure 4, in the uplink where the target terminal transmits data to the target base station, the fake base station receives the communication data from the target terminal and transmits it to the target base station via the fake terminal. Correspondingly, in the downlink where the target base station transmits data to the target terminal, the fake terminal receives the communication data from the legitimate base station, modifies the received data via the fake base station, and then transmits it to the target terminal.

[0092] During this process, it is difficult for the target terminal and the target base station to detect the existence of fake base stations and fake terminals. If there is no integrity protection for communication data between the target terminal and the target base station, attacks such as data tampering or packet loss may occur.

[0093] Figure 5 illustrates a network architecture diagram provided in an embodiment of this application. This network architecture may include: access network equipment and at least one terminal device, such as UE1 and UE2. The above network architecture can be an architecture in an LTE system, an architecture in an NR system, a hybrid LTE and NR architecture, or an architecture in a new communication system that will emerge in future communication developments; this application is not limited to any of these.

[0094] To prevent attacks from fake base stations and man-in-the-middle attacks, data between access network devices and terminal devices can be encrypted or protected for integrity using keys. Air interface integrity protection generally includes the following process: The sending end uses regularly varying parameters and the transmitted data to perform calculations according to certain rules to obtain a message authentication code for integrity (MAC-I). The receiving end uses the same parameters and the same algorithm to calculate an expected message authentication code for integrity (XMAC-I), and verifies both the MAC-I and XMAC-I to determine if the data reception is complete, thereby achieving the purpose of protecting data integrity. As shown in Figure 6, taking the NR integrity protection algorithm (NIA) as an example, the input parameters of NIA can include the integrity protection key (KEY), the PDCP packet count (COUNT), the bearer identifier, the transmission direction (DIRECTION), and the message to be transmitted (i.e., MESSAGE). The sending end appends the MAC-I to the message when sending it. The receiving end uses the same method to calculate the XMAC-I of the received message and verifies the integrity of the message by comparing the MAC-I and XMAC-I. The transmission direction is indicated as uplink or downlink; for example, 0 represents uplink and 1 represents downlink.

[0095] The air interface encryption protection process is similar to the integrity protection process, as shown in Figure 7. Taking the NR Encryption Algorithm (NEA) as an example, the input parameters of the air interface encryption algorithm include the encryption key (KEY), the PDCP packet count (COUNT), the bearer identifier, the transmission direction (DIRECTION), and the required key stream length (LENGTH). During encryption, the sending end generates a key stream block (KEYSTREAMBLOCK) based on the input parameters. This key stream block is XORed with the plaintext block (PLAINTEXTBLOCK) to generate a ciphertext block (CIPHERTEXTBLOCK). At the receiving end, the same key stream block is generated using the same input parameters, and an XOR operation is performed on the ciphertext block to recover the plaintext block.

[0096] Currently, during network access, information obtained during random access is not encrypted or protected for integrity before the activation of secure mode, posing a risk of information leakage or tampering and thus threatening the security of the terminal device. Therefore, this application provides a method to improve the security of communication between the terminal device and the base station before activating secure mode.

[0097] The method will be described below from the perspective of the interaction between the terminal device and the access network device. The steps executed by the terminal device can also be implemented by components within the terminal device (such as a baseband chip, or other processing units or processor modules). Similarly, the steps executed by the access network device can also be implemented by components within the access network device (such as a baseband chip, or other processing units or processor modules).

[0098] It is understood that this application does not specifically limit the structure of the execution subject of the method provided in the embodiments of this application. It can be applied to modules in terminal devices or access network devices, as long as they can communicate according to the method provided in the embodiments of this application by running a program that records the code of the method provided in the embodiments of this application. The following description takes the interaction between terminal devices and access network devices as an example.

[0099] Figure 8 shows a flowchart of a communication method provided in an embodiment of this application. The method includes:

[0100] Step 801: The terminal device generates a MAC protocol data unit (PDU).

[0101] The terminal device can be in an RRC inactive state. A MAC PDU can include multiple MAC subPDUs, each subPDU comprising a MAC service data unit (SDU) or a MAC control element (CE). The MAC PDU includes a first MAC SDU and N information units, where each information unit is a MAC SDU or MAC CE, and N is a positive integer. The N information units can be understood as Layer 2 information transmitted along with the Physical Uplink Shared Channel (PUSCH) portion of message 3 or message A. The first MAC SDU includes the PUSCH portion of message 3 or message A in the random access process. Message 3 is the third message in the four-step random access process, for example, when the terminal device is in an RRC inactive state. Message 3 can be an RRC Resume Request message, used to request the restoration of the RRC connection. This message can include the reason for the RRC connection restoration and the terminal device's first identifier. For example, this first identifier could be an inactive radio network temporary identity (I-RNTI). Message A is the first message in the two-step random access process. The PUSCH part of message A can refer to the information transmitted through PUSCH in message A.

[0102] In another implementation, the logical channel identifier (LCID) of the first MAC SDU is an index of the common control channel (CCCH).

[0103] A MAC subPDU may also include other fields. For example, as shown in Figure 9, a MAC PDU includes multiple MAC subPDUs. Some MAC subPDUs include MAC SDUs and can be called MAC subPDUs including MAC SDUs; others include MAC CEs and can be called MAC subPDUs including MAC CEs. The header of a MAC subPDU may include a Reversed (R) field, a Formulation (F) field, a Logical Channel Identifier (LCID) field, and a Length subheader (L) field. MAC CEs can be divided into variable-sized MAC CEs and fixed-sized MAC CEs. If a MAC subPDU includes a fixed-sized MAC CE, the Length subheader field may not be included. Optionally, a MAC PDU may also include other information, such as padding bits.

[0104] In one implementation, the access network device may further send first information. Correspondingly, the terminal device receives the first information from the access network device, the first information indicating encryption and / or integrity protection of information during the random access process, whereby the information during the random access process may refer to the MAC CE or MAC SDU sent by the terminal device during the random access process. The first information may also indicate at least one of the following:

[0105] Encryption is performed using a first key determined based on the security context of the first access stratum (AS).

[0106] Encryption is performed using an encryption algorithm determined based on the first AS security context;

[0107] Integrity protection is performed using an integrity protection key determined based on the first AS security context;

[0108] Integrity protection is performed using an integrity protection algorithm determined based on the security context of the first AS.

[0109] The first AS security context is configured by the access network device for the terminal device. When the RRC connection is released, the terminal device in the RRC inactive state can retain the first AS security context, that is, the terminal device has the first AS security context. The first AS security context may include at least one of the following: a first key, an encryption algorithm, an integrity protection key, and an integrity protection algorithm.

[0110] For example, when releasing the RRC connection of a terminal device, the access network device sends first information via an RRC release message. Based on the first information, the terminal device determines whether to encrypt and / or protect the integrity of information during the random access process when the RRC connection is subsequently restored.

[0111] In one implementation, the access network device may further send second information. Correspondingly, the terminal device receives the second information from the access network device, which indicates a RAN-based notification area (RNA) list or a cell list. The RNA list includes at least one RNA, and the cell list includes at least one cell. The area corresponding to the RNA list or cell list is the effective area of ​​the first key or the first information; that is, if the terminal device is within the area corresponding to the RNA list or cell list, the terminal device needs to encrypt and / or protect the integrity of information during the random access process. The area corresponding to the RNA list or cell list can also be understood as the area range within which information during the random access process needs to be encrypted and / or protected for integrity. If the cell where the terminal device is located is within the RNA list or cell list, the terminal device can execute step 801.

[0112] In another implementation, the access network device can also send third information. Correspondingly, the terminal device receives third information from the access network device, indicating whether encryption and / or integrity protection of information during the random access process is permitted in a second cell outside the first cell of the access network device. If the third information indicates that encryption and / or integrity protection of information during the random access process is permitted in a second cell outside the first cell, then the terminal device can perform encryption and / or integrity protection of information during the random access process in the second cell outside the first cell.

[0113] In one implementation, the access network device may also send fourth information. Correspondingly, the terminal device receives the fourth information from the access network device, which indicates that the access network device or its cell supports encryption and / or integrity protection of information during the random access process. The terminal device receives the fourth information in the access network device's cell, and based on this information, it can determine that the access network device's cell supports Layer 2 message verification, and then proceed to step 801.

[0114] In this application, the second or third information can be sent with the first information via the same message, such as via an RRC release message. Alternatively, the second or third information can be sent with a different message than the first information, such as via system information.

[0115] In one implementation, if the access network device includes a CU and a DU, or if the access network device also includes an O-CU and an O-DU, the first information, the second information, and the third information can be sent by the CU or the O-CU.

[0116] In this application, there may be multiple ways to encrypt and / or protect the integrity of information during the random access process. Several examples are given below.

[0117] In the first implementation method, the N information units in the MAC PDU are encrypted using a first key. The first key is determined based on the first AS security context of the terminal device. For example, the first key is the key included in the first AS security context.

[0118] The specific process of encrypting N information units using the first key is not limited in this application; for example, the process shown in Figure 7 can be referred to. The encryption algorithm is either preset or determined based on the first AS security context, such as NEA. The input parameters of the encryption algorithm include the first key, the PDCP packet count (COUNT), the bearer identifier, the transmission direction (DIRECTION), the cell identifier, and the length of the required key stream (LENGTH). The PDCP packet refers to a PDCP packet including a MAC PDU, which can also be understood as a PDCP packet including the PUSCH portion of message 3 or message A; the transmission direction indicates uplink or downlink, for example, 0 for uplink and 1 for downlink; the bearer identifier refers to the identifier of the bearer corresponding to the MAC PDU. The cell identifier is the identifier of the cell where the terminal device is located, which can also be replaced by the identifier of the access network device. If there is a cross-site situation, such as the terminal device moving from the first cell of the first access network device to the second cell of the second access network device, the input parameters of the encryption algorithm can include the first cell identifier and the second cell identifier; the first cell identifier can also be replaced by the identifier of the first access network device, and the second cell identifier can also be replaced by the identifier of the second access network device. The cell identifier is the physical cell index (PCI), and the identifier of the access network device can be understood as the cell global identity (CGI).

[0119] When encrypting N information units using the first key, a keystream block is generated based on the input parameters. This keystream block is then XORed with the input plaintext (i.e., the N information units) to generate a ciphertext block, which is then sent. At the receiving end, the same keystream block is generated using the same encryption algorithm and input parameters, and the plaintext is recovered by XORing the ciphertext block with the keystream.

[0120] In the second implementation method, the MAC-I corresponding to the PUSCH portion of message 3 or message A is determined based on N information units. This MAC-I is used to protect the integrity of the PUSCH portion of message 3 or message A. This MAC-I can be located in the first MAC SDU.

[0121] In one implementation, MAC-I is determined based on at least one of the following:

[0122] The hash value is determined based on at least one of the N information units;

[0123] The cyclic redundancy check (CRC) value determined based on at least one of the N information units;

[0124] The first value is determined based on the M logical channel identifiers (LCIDs) corresponding to the M information units among the N information units, where M is an integer less than or equal to N; wherein, the LCID corresponding to an information unit can be any of the LCIDs included in that information unit.

[0125] This application does not limit how the first value is determined based on the M LCIDs. For example, the first value can be the sum of the M LCIDs, or it can be a hash value determined based on the M LCIDs. As another example, the first value can be a CRC value determined based on the M LCIDs.

[0126] For example, based on the preceding description, taking message 3 as an example, the terminal device can use the integrity protection key, the PDCP packet count value, the bearer identifier, the transmission direction, the cell identifier, message 3, and the first value as input parameters to the integrity protection algorithm to obtain the MAC-I. The integrity protection algorithm can be preset or it can be an integrity protection algorithm located in the first AS security context, such as the NIA integrity protection algorithm. The cell identifier can also be replaced with the identifier of the access network device. Correspondingly, at the receiving end, XMAC-I is generated using the same integrity protection algorithm and input parameters, and the XMAC-I and MAC-I are compared to determine whether the integrity verification has passed. If there is a cross-site situation, such as the terminal device moving from the first cell of the first access network device to the second cell of the second access network device, the input parameters of the encryption algorithm can include the first cell identifier and the second cell identifier; the first cell identifier can also be replaced with the identifier of the first access network device, and the second cell identifier can also be replaced with the identifier of the second access network device.

[0127] In one implementation, the integrity protection key and integrity protection algorithm used to determine MAC-I can be determined based on the first AS security context of the terminal device. For example, the integrity protection key used to determine MAC-I can be a first key, or it can be a preset key.

[0128] Optionally, MAC-I can also be determined based on channel state information (CSI), which is obtained by the terminal device from the reference signal measured from the access network device.

[0129] For example, based on the preceding description, taking message 3 as an example, the terminal device can use the integrity protection key, the PDCP packet count value, the bearer identifier, the transmission direction, message 3, CSI, the cell identifier where the terminal device is currently located, and the first value as input parameters for the integrity protection algorithm to obtain MAC-I.

[0130] The above are just examples. Terminal devices can also use other methods to encrypt and / or protect the integrity of information during the random access process, which will not be elaborated here.

[0131] If this application is applied to a four-step random access procedure, the terminal device may also send a random access request message before step 801. Before sending the random access request message, the terminal device is in an RRC inactive state.

[0132] This random access request message is used to initiate random access. The random access request message can be a preamble, a random access preamble, or a name such as message 1 in the random access process; this application does not limit this.

[0133] Access network equipment can send a random access response (RAR) message to a terminal device based on a random access request message from the terminal device. The random access response message can be referred to by names such as message 2 in the random access process, and this application is not limited to this. The random access response message may include uplink grant information, which is used to schedule the transmission resources of message 3 in the random access process.

[0134] This application does not limit the specific content of the random access request message and the random access response message, and will not elaborate further here.

[0135] Step 802: The terminal device sends a MAC PDU to the access network device.

[0136] Correspondingly, the access network equipment receives MAC PDUs from the terminal equipment.

[0137] Step 803: The access network device decrypts the N information units, or verifies the MAC-I based on the N information units.

[0138] In one implementation, the access network device decrypts N information units based on a second key.

[0139] The second key is determined based on the first identifier of the terminal device. The access network device can determine the second AS security context of the terminal device based on the first identifier, and then determine the second key based on the second AS security context. This second AS security context is associated with the first identifier, and the access network device stores this second AS security context. It is understood that if the first identifier of the terminal device has not been tampered with, then the second AS security context is the same as the first AS security context in the terminal device, and the second key is the same as the first key.

[0140] If the access network device can recognize the decrypted N information units, or if the access network device supports the information format of the decrypted N information units, then the access network device can successfully decrypt the N information units. Conversely, if the access network device cannot recognize one or more of the decrypted N information units, or if the access network device cannot support the information format of one or more of the decrypted N information units, then the access network device cannot successfully decrypt the N information units. This can be interpreted as a failure to decrypt the N information units.

[0141] If the decryption of N information units is successful, the access network device can send message 4 or message B during the random access process to the terminal device; if the decryption of N information units fails, the access network device can release the radio resource control connection of the terminal device and discard the N information units.

[0142] In one implementation, the access network device can determine the XMAC-I based on N information elements. The integrity protection algorithm used by the access network device to determine the XMAC-I is the same as the integrity protection algorithm used by the terminal device to determine the MAC-I, and the types of input parameters for the integrity protection algorithms are the same. The specific process of determining the XMAC-I based on N information elements will not be elaborated further. If the XMAC-I is the same as the MAC-I, the MAC-I verification passes, and the access network device can send message 4 or message B in the random access process to the terminal device; if the XMAC-I is different from the MAC-I, the MAC-I verification fails, and the access network device can release the radio resource control connection of the terminal device.

[0143] The method provided in this application improves the security of information transmitted during random access by encrypting the N information units sent along with the PUSCH portion of message 3 or message A, or by protecting the integrity of the PUSCH portion of message 3 or message A based on the N information units, thereby achieving secure protection of MAC layer information and improving system security.

[0144] In this application, the access network device may also include CU and DU, or in an O-RAN architecture, the access network device may also include O-CU and O-DU. The following description, using an access network device including CU and DU as an example, illustrates how the access network device decrypts N information elements or verifies MAC-I based on N information elements.

[0145] Figure 10 shows a flowchart of a communication method provided in an embodiment of this application. The method includes:

[0146] Step 1001: The terminal device sends a MAC PDU.

[0147] Correspondingly, the DU receives MAC PDUs from the terminal device.

[0148] The MAC PDU can be referred to in the description of step 801, and will not be repeated here.

[0149] Implementation Method 1: N information units are encrypted using a first key.

[0150] Step 1002a: The DU sends the first MAC SDU to the CU.

[0151] In this implementation, the DU parses the MAC subPDU that includes the first MAC SDU from the MAC PDU, obtains the first MAC SDU, and sends the first MAC SDU to the CU through the F1 interface. The first MAC SDU includes the first identifier of the terminal device, for example, the first identifier is I-RNTI.

[0152] Step 1003a: The CU sends a verification instruction message to the DU, which instructs the DU to decrypt N information units.

[0153] The CU verifies the identity of the terminal device based on the first identifier and can determine the second AS security context associated with the first identifier, and then sends the second AS security context to the DU. The DU can determine the second key based on the second AS security context, and then decrypt N information units based on the second key. The specific process will not be elaborated here.

[0154] Implementation Method 2: The MAC-I corresponding to the PUSCH part of message 3 or message A is determined based on N information units.

[0155] Step 1002b: DU sends N information units to CU.

[0156] In this implementation, the DU parses the MAC PDU, obtains N information units, and sends the N information units to the CU through the F1 interface.

[0157] Step 1003b: The CU verifies MAC-I based on N information units.

[0158] The CU can determine the XMAC-I based on N information units. The method by which the CU determines the XMAC-I can be the same as the method by which the terminal device determines the MAC-I. If the XMAC-I is the same as the MAC-I, then the MAC-I verification passes; if the XMAC-I is different from the MAC-I, then the MAC-I verification fails.

[0159] In the O-RAN architecture, the CU above can be replaced with O-CU, and the DU can be replaced with O-DU. The specific process will not be elaborated here.

[0160] The method provided in this application can also be applied to scenarios involving cross-site operations of terminal devices. That is, after a terminal device is released to an RRC inactive state, when the RRC inactive terminal device subsequently restores its RRC connection, it can initiate an RRC connection restoration process with another access network device. In the example below, the first access network device releases the terminal device's RRC connection, and the terminal device is released to an RRC inactive state. The RRC inactive terminal device then restores its RRC connection through the second access network device. The first access network device includes a first DU and a first CU, and the second access network device includes a second DU and a second CU.

[0161] Figure 11 shows a flowchart of a communication method provided in an embodiment of this application. The flowchart uses message 3 as an example, and the method includes:

[0162] Optionally, step 1101: The first CU sends the first information.

[0163] The first message can be sent via an RRC release message. After receiving the first message, the terminal device enters an RRC inactive state. The first CU may also send other messages.

[0164] In the first implementation, the first CU can also send a second message, which indicates a list of RNAs or a list of cells.

[0165] In the second implementation, the first CU can also send a third message, which indicates that cross-access network devices are allowed to encrypt and / or protect the integrity of information during the random access process.

[0166] Taking the example of a terminal device moving to the coverage area of ​​a second access network device.

[0167] Optionally, in step 1102: the second CU sends a fourth message indicating that it supports encryption and / or integrity protection of information during the random access process across access network devices.

[0168] The terminal device can initiate random access to the second access network device to restore the RRC connection. Please refer to the following procedure for details.

[0169] Step 1103: The terminal device sends a random access request message.

[0170] Accordingly, the second DU receives the random access request message.

[0171] Random access request messages can have a preamble.

[0172] If the first CU sends the second information, then before step 1103, if the terminal device determines that the second cell is in the RNA list or the cell list, it sends a random access request message, and the second cell is the cell where the terminal device is currently located.

[0173] If the first CU sends the third information, then before step 1103, if the terminal device determines that it will receive the fourth information in the second cell, it will send a random access request message.

[0174] Step 1104: The second DU sends a random access response message to the terminal device.

[0175] Step 1105: The terminal device sends a MAC PDU to the second DU.

[0176] The MAC PDU includes a first MAC SDU and N information elements. The first MAC SDU includes message 3 from the random access procedure. The first MAC SDU includes the first identifier of the terminal device.

[0177] In the first implementation method, N information units are encrypted using a first key.

[0178] Step 1106a: The second DU sends the first MAC SDU and N information units to the second CU.

[0179] Step 1107a: The second CU sends the first MAC SDU and N information units to the first CU.

[0180] The second CU can send the first MAC SDU and N information units to the first CU via the Xn interface. Alternatively, the second CU may send the first identifier instead of the first MAC SDU.

[0181] Optionally, the second CU sends its cell identifier or second access network device identifier to the first CU. The cell identifier or second access network device identifier can be the input parameter of an encryption algorithm that encrypts N information units.

[0182] Step 1108a: The first CU sends the second AS security context and N information units to the first DU.

[0183] The first CU can also send verification instruction information to the first DU, which instructs the decryption of N information units.

[0184] The first CU verifies the identity of the terminal device based on the first identifier and can determine the second AS security context associated with the first identifier.

[0185] The first DU determines the second key based on the second AS security context, and decrypts N information units based on the second key.

[0186] If the first decryption unit (DU) can recognize the N decrypted information units, or if the first DU supports the information format of the N decrypted information units, then the first DU can decode the N decrypted information units, which can be understood as successful decryption of the N information units. If the first DU cannot recognize one or more of the N decrypted information units, or if the first DU cannot support the information format of one or more of the N decrypted information units, then the first DU cannot decode one or more of the N decrypted information units, which can be understood as failed decryption of the N information units.

[0187] Step 1109a: The first DU can send the decryption result to the first CU, indicating whether the decryption was successful or failed.

[0188] Step 1110a: The first CU sends the decryption result to the second CU.

[0189] If the decryption result indicates successful decryption, the second CU can send message 4 during the random access process to the terminal device; if the decryption result indicates failed decryption, the wireless resource control connection of the terminal device is released.

[0190] In another implementation, if the first DU can identify the decrypted N information units, that is, the decryption of N information units is successful, the first CU can send message 4 through the second CU. At this time, the second CU receives the feedback message sent by the first CU on Xn, and the feedback message includes message 4.

[0191] In the second implementation method, the MAC-I corresponding to message 3 is determined based on N information units, and this MAC-I is located in the first MAC SDU.

[0192] Step 1106b: The second DU sends the first MAC SDU and N information units to the second CU.

[0193] Alternatively, the N information units may not be sent to the second CU. For example, the second DU may send parameters for determining MAC-I, such as a hash value determined based on at least one of the N information units, a CRC value determined based on at least one of the N information units, and a first value.

[0194] Step 1107b: The second CU sends the first MAC SDU and N information units to the first CU.

[0195] Alternatively, the N information units may not be sent. For example, parameters for determining XMAC-I may be sent, such as a hash value determined based on at least one of the N information units, a CRC value determined based on at least one of the N information units, and a first value.

[0196] Optionally, the second CU sends its cell identifier or second access network device identifier to the first CU. The cell identifier or second access network device identifier can be an input parameter for determining the integrity protection algorithm of MAC-I.

[0197] Step 1108b: MAC-I corresponding to the first CU verification message 3.

[0198] The first CU can determine XMAC-I based on N information units and compare whether XMAC-I and MAC-I are the same, thereby verifying MAC-I. The specific process of verifying MAC-I is not limited and will not be elaborated here.

[0199] Step 1109b: The first CU sends the verification result to the second CU.

[0200] The verification result indicates whether the MAC-I verification passed or failed. If the verification result indicates that the verification passed, the second CU can send message 4 of the random access procedure to the terminal device; if the verification result indicates that the verification failed, the radio resource control connection of the terminal device is released.

[0201] In another implementation, decryption or integrity verification can also be performed by a second access network device. Figure 12 shows a flowchart of a communication method provided in an embodiment of this application. The flowchart uses message 3 as an example, and the method includes:

[0202] Step 1201: The terminal device sends a MAC PDU to the second DU.

[0203] The MAC PDU includes a first MAC SDU and N information elements. The first MAC SDU includes message 3 from the random access procedure. The first MAC SDU includes the first identifier of the terminal device.

[0204] Before step 1201, steps 1101 to 1104 may also be included, as detailed in the preceding description.

[0205] In the first implementation method, N information units are encrypted using a first key.

[0206] Step 1202a: The second DU sends the first MAC SDU to the second CU.

[0207] Step 1203a: The second CU sends the first MAC SDU to the first CU.

[0208] The second CU can send the first MAC SDU to the first CU through the Xn interface.

[0209] In another implementation, the second CU can send the first identifier from the first MAC SDU to the first CU without sending the first MAC SDU itself.

[0210] Step 1204a: The first CU sends the second AS security context associated with the first identifier to the second CU.

[0211] The first CU verifies the identity of the terminal device based on the first identifier and can determine the second AS security context associated with the first identifier. If the first identifier has not been tampered with, the first AS security context and the second AS security context are the same.

[0212] Optionally, the first CU sends its cell identifier or the first access network device identifier to the second CU. The cell identifier or the first access network device identifier can be the input parameter of an encryption algorithm that encrypts N information units.

[0213] Step 1205a: The second CU sends the second AS security context to the second DU.

[0214] Step 1206a: The second DU determines the second key based on the second AS security context, and decrypts N information units based on the second key.

[0215] Optionally, if the second DU can recognize the decrypted N information units, or the second DU can support the information format of the decrypted N information units, or the second DU can interpret the decrypted N information units, it can be understood that the decryption of the N information units is successful, and the second CU can send message 4 in the random access process to the terminal device.

[0216] If the second DU cannot recognize one or more of the decrypted N information units, or if the second DU cannot support the information format of one or more of the decrypted N information units, or if the second DU cannot interpret one or more of the decrypted N information units, it can be understood as a failure to decrypt the N information units, and the wireless resource control connection of the terminal device can be released.

[0217] In the second implementation method, the MAC-I corresponding to message 3 is determined based on N information units, and this MAC-I is located in the first MAC SDU.

[0218] Step 1202b: The second DU sends the first MAC SDU and N information units to the second CU.

[0219] Alternatively, the N information units may not be sent to the second CU. For example, the second DU may send parameters for determining XMAC-I, such as a hash value determined based on at least one of the N information units, a CRC value determined based on at least one of the N information units, and a first value.

[0220] Step 1203b: The second CU sends the first MAC SDU to the first CU.

[0221] Step 1204b: The first CU sends the second AS security context associated with the first identifier to the second CU.

[0222] The first CU verifies the identity of the terminal device based on the first identifier and can determine the second AS security context associated with the first identifier. If the first identifier has not been tampered with, the first AS security context and the second AS security context are the same.

[0223] Optionally, the first CU sends its cell identifier or the first access network device identifier to the second CU. The cell identifier or the first access network device identifier can be the input parameter for determining the integrity protection algorithm of MAC-I.

[0224] Step 1205b: MAC-I corresponding to the first CU verification message 3.

[0225] The first CU can determine XMAC-I based on N information units and compare whether XMAC-I and MAC-I are the same, thereby verifying MAC-1. The specific process of verifying MAC-1 is not limited and can be referred to the previous description, which will not be repeated here.

[0226] If the verification passes, the first CU can send message 4 during the random access process to the terminal device; if the verification fails, the radio resource control connection of the terminal device is released.

[0227] In the O-RAN architecture, the first CU in the processes of Figures 11 and 12 above can be replaced with the first O-CU, the first DU can be replaced with the first O-DU, the second CU can be replaced with the second O-CU, and the second DU can be replaced with the second O-DU. The specific process will not be repeated here.

[0228] This application also provides a method that enables a terminal device in the RRC idle state to protect the Layer 2 information sent along with the PUSCH portion of message 3 or message A during random access, which will be described in detail below.

[0229] Figure 13 shows a flowchart of a communication method provided in an embodiment of this application. The method includes:

[0230] Step 1301: The terminal device generates a MAC PDU.

[0231] The terminal device can be in the RRC idle state. A MAC PDU can include multiple MAC subPDUs, each including a MAC SDU or MAC CE. The MAC PDU includes a first MAC SDU and N information elements, where each information element is a MAC SDU or MAC CE, and N is a positive integer. The N information elements can be understood as Layer 2 information sent along with the PUSCH portion of message 3 or message A. The first MAC SDU includes the PUSCH portion of message 3 or message A in the random access process, and may include the terminal device's first identifier. Message 3 is the third message in the four-step random access process, for example, when the terminal device is in the RRC idle state. Message 3 can be an RRC Setup Request message, used to request the establishment of an RRC connection, and this message may include the terminal device's first identifier. For example, this first identifier could be ng-5G-S-TMSI-part1, which is the rightmost 39 bits of the 5G serving-temporary mobile subscriber identity (5G-S-TMSI).

[0232] The first identifier can be determined based on the identifier of the core network equipment set. For example, 5G-S-TMSI can be represented as:

[0233] <5G-S-TMSI>=<AMF set ID><AMF pointer> <5G-TMSI>. The 5G-S-TMSI consists of 48 bits, the AMF set ID consists of 10 bits, the AMF pointer consists of 6 bits, and the 5G-TMSI consists of 32 bits. The AMF set ID can be an identifier for a set of core network devices, which can be access and mobility management function (AMF) network elements.

[0234] In this application, the N information elements in the MAC PDU are encrypted and / or protected with a first key. The first key is determined based on the terminal device's non-access stratum key or associated with the terminal device's non-access stratum key. For example, the first key is a key derived from the non-access stratum key. The non-access stratum key is configured by the access network device for the terminal device. The terminal device in the RRC idle state can store the non-access stratum key, that is, the terminal device in the RRC idle state has a non-access stratum key. For example, the first key and the non-access stratum key are both derived from the same key in different ways.

[0235] The specific process of encrypting N information units using the first key is not limited in this application; for example, the process shown in Figure 7 can be referred to. The encryption algorithm is preset, for example, NEA. The input parameters of the encryption algorithm include the first key, the PDCP packet count (COUNT), the bearer identifier, the transmission direction (DIRECTION), the cell identifier, and the length of the required key stream (LENGTH). Here, a PDCP packet refers to a PDCP packet including a MAC PDU; the transmission direction indicates uplink or downlink, for example, 0 for uplink and 1 for downlink; the bearer identifier refers to the identifier of the bearer corresponding to the MAC PDU. The cell identifier is the identifier of the cell where the terminal device is located; the cell identifier can also be replaced by the identifier of the access network device.

[0236] When encrypting N information units using the first key, a keystream block is generated based on the input parameters. This keystream block is then XORed with the input plaintext (i.e., the N information units) to generate a ciphertext block, which is then sent. At the receiving end, the same keystream block is generated using the same encryption algorithm and input parameters, and the plaintext is recovered by XORing the ciphertext block with the keystream.

[0237] This application does not limit the specific process of using the first key to protect the integrity of N information units. For example, the terminal device can use the first key (i.e., the integrity protection key), the PDCP packet count value, the bearer identifier, the transmission direction, the cell identifier, and the information to be transmitted (e.g., N information units) as input parameters for the integrity protection algorithm to obtain MAC-I. The integrity protection algorithm can be preset, for example, the integrity protection algorithm is NIA. The cell identifier can also be replaced with the identifier of the access network device. Correspondingly, at the receiving end, XMAC-I is generated using the same integrity protection algorithm and input parameters, and the XMAC-I and MAC-I are compared to determine whether the integrity verification has passed.

[0238] In one implementation, the access network device may further send first indication information. Correspondingly, the terminal device receives the first indication information from the access network device, which instructs encryption and / or integrity protection of information during the random access process. This information may refer to the MAC CE or MAC SDU sent by the terminal device during the random access process. The first indication information may also instruct encryption and / or integrity protection using a first key determined based on a non-access stratum (NAS) key.

[0239] For example, when releasing the RRC connection of a terminal device, the access network device sends a first indication message via an RRC release message. Based on the first indication message, the terminal device determines to encrypt the information during the random access process when the RRC connection is subsequently restored.

[0240] The terminal device's first identifier is unique within the tracking area corresponding to the current core network device set. In one implementation, the access network device can also send third indication information. Accordingly, the terminal device receives the third indication information from the access network device, which indicates that it should not leave the tracking area corresponding to the current core network device set, or that the non-access stratum key, the first key, or the terminal device's first identifier cannot be used across access network devices; that is, if the terminal device switches to another access network device, the non-access stratum key, the first key, or the terminal device's first identifier becomes invalid.

[0241] In one implementation, the terminal device receives second indication information, which indicates a core network device set or a tracking area (TA) corresponding to the core network device set. The tracking area corresponding to the core network device set is the effective area for a non-access stratum key, a first key, or a first identifier of the terminal device; alternatively, the tracking area corresponding to the core network device set is an area for encrypting and / or protecting the integrity of information during the random access process. When the terminal device is located in the tracking area corresponding to the core network device set, it can use the first key to encrypt and / or protect the integrity of information during the random access process.

[0242] For example, the access network device can send a second indication message, which indicates the core network device set identifier, such as the AMF set ID. As another example, the core network device can send a second indication message, which indicates the tracking area corresponding to the core network device set. When the terminal device receives the second indication message, it can determine whether to move outside the tracking area corresponding to the core network device set.

[0243] If the terminal device initiates an RRC connection or random access procedure again within the tracking area corresponding to the core network device set after the terminal device has released the RRC connection in the tracking area corresponding to the core network device set, the terminal device can execute step 1301.

[0244] If this application is applied to a four-step random access procedure, the terminal device may also send a random access request message before step 1301. This random access request message is used to initiate random access. The access network device can then send a random access response message to the terminal device based on the random access request message from the terminal device.

[0245] Optionally, the second indication information sent by the access network device can indicate multiple core network device set identifiers, with each core network device set identifier associated with at least one random access request message. The random access request message sent by the terminal device is associated with the core network device set identifier corresponding to the first identifier, thus enabling the network side to determine the core network device set identifier based on the random access request message. The first identifier is determined based on the core network device set identifier corresponding to the first identifier.

[0246] This application does not limit the specific content of the random access request message and the random access response message, and will not elaborate further here.

[0247] Step 1302: The terminal device sends a MAC PDU to the access network device.

[0248] Correspondingly, the access network equipment receives MAC PDUs from the terminal equipment.

[0249] In this application, the access network equipment can decrypt and / or verify the integrity of the N information units, or the core network equipment can decrypt and / or verify the integrity of the N information units, as described below.

[0250] In the first implementation method, the core network equipment decrypts and / or verifies the integrity of N information units.

[0251] Step 1303a: The access network device sends the terminal device's first identifier and N information units to the core network device.

[0252] Correspondingly, the core network equipment receives the first identifier and N information units from the terminal equipment.

[0253] Among them, the core network equipment can be AMF network elements.

[0254] Step 1304a: The core network equipment can decrypt N information units according to the second key and / or perform integrity verification on N information units according to the second key.

[0255] The second key is determined based on the non-access stratum key corresponding to the first identifier. If the first identifier of the terminal device has not been tampered with, then the non-access stratum key determined by the core network device based on the first identifier is the same as the non-access stratum key in the terminal device, therefore the second key is the same as the first key.

[0256] The specific process of core network equipment decrypting N information units and / or performing integrity verification on N information units will not be elaborated here.

[0257] Step 1305a: The core network device sends verification information to the access network device, indicating whether decryption was successful and / or whether integrity verification was passed.

[0258] Correspondingly, the access network equipment receives the authentication information.

[0259] If the verification information indicates that the decryption of N information units is successful and / or the integrity verification is passed, the access network device may send message 4 or message B in the random access process to the terminal device; if the verification information indicates that the decryption of N information units fails or the integrity verification fails, the radio resource control connection of the terminal device is released.

[0260] Implementation method two: The access network device decrypts and / or verifies the integrity of N information units.

[0261] Step 1303b: The access network device sends the first identifier of the terminal device to the core network device.

[0262] Correspondingly, the core network equipment receives the first identifier of the terminal equipment.

[0263] Among them, the core network equipment can be AMF network elements.

[0264] Core network equipment can request the non-access stratum key corresponding to the first identifier by sending the first identifier.

[0265] Step 1304b: The core network device sends the non-access stratum key to the access network device.

[0266] Correspondingly, the access network equipment receives the non-access stratum key.

[0267] The core network equipment can determine the non-access stratum key of the terminal equipment based on the first identifier, and the first identifier is associated with the non-access stratum key of the terminal equipment.

[0268] Step 1305b: The access network device decrypts N information units and / or performs integrity verification on the N information units.

[0269] The access network device decrypts N information units and / or performs integrity verification on N information units using the second key. The second key is determined based on the non-access stratum key corresponding to the first identifier. If the first identifier of the terminal device has not been tampered with, then the non-access stratum key determined by the core network device based on the first identifier is the same as the non-access stratum key in the terminal device; therefore, the second key is the same as the first key.

[0270] The specific process of the access network device decrypting N information units and performing integrity verification on N information units can be referred to the previous description, and will not be repeated here.

[0271] If the decryption of N information units is successful and / or the integrity verification is passed, the access network device can send message 4 or message B during the random access process to the terminal device; if the decryption of N information units fails or the integrity verification fails, the radio resource control connection of the terminal device is released.

[0272] In one implementation, the access network device can encrypt message 4 or message B using a first key. Correspondingly, the terminal device receives message 4 or message B and decrypts it. If the terminal device can recognize the decrypted message 4 or message B, or if the terminal device supports the message format of the decrypted message 4 or message B, and the terminal device can interpret the decrypted message 4 or message B, it can be understood that the decryption of message 4 or message B has been successful. If the terminal device cannot recognize the decrypted message 4 or message B, or if the terminal device does not support the message format of the decrypted message 4 or message B, and the terminal device cannot interpret the decrypted message 4 or message B, it can be understood that the decryption of message 4 or message B has failed.

[0273] If the terminal device successfully decrypts message 4 or message B, the random access is successful; if it fails to decrypt message 4 or message B, it initiates an RRC re-establishment.

[0274] The method provided in this application improves the security of information transmitted during random access by encrypting and / or protecting the integrity of N information units sent along with the PUSCH portion of message 3 or message A, thereby achieving secure protection of MAC layer information and enhancing system security.

[0275] It is understood that, in order to implement the functions in the above embodiments, the terminal device or access network device includes hardware structures and / or software modules corresponding to perform each function. Those skilled in the art should readily recognize that, based on the units and method steps of the various examples described in conjunction with the embodiments disclosed in this application, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware depends on the specific application scenario and design constraints of the technical solution.

[0276] The following are schematic diagrams of possible communication devices provided in the embodiments of this application. These communication devices can be used to implement the functions of terminal devices or access network devices in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments.

[0277] As shown in Figure 14, the communication device 1400 includes a processing unit 1410 and a communication unit 1420. The communication device 1400 is used to implement the functions of the terminal device or access network device in the various method embodiments shown above.

[0278] When the communication device 1400 is used to implement the functions of a terminal device:

[0279] A processing unit is configured to generate a Media Access Control (MAC) Protocol Data Unit (PDU); the MAC PDU includes a first MAC Service Data Unit (SDU) and N information units, wherein each information unit is a MAC SDU or a MAC Control Element (CE), and N is an integer greater than 0. The first MAC SDU includes message 3 from the random access process; wherein the N information units are encrypted using a first key, which is determined based on the first access layer (AS) security context of the terminal device; or the message integrity authentication code (MAC-I) corresponding to message 3 is determined based on the N information units; the terminal device is in a radio resource control inactive state.

[0280] A communication unit is used to send the MAC PDU to the access network equipment.

[0281] When the communication device 1400 is used to implement the functions of an access network device:

[0282] A communication unit is used to receive a Media Access Control (MAC) Protocol Data Unit (PDU) from a terminal device. The MAC PDU includes a first MAC Service Data Unit (SDU) and N information units, where each information unit is a MAC SDU or a MAC Control Element (CE). The first MAC SDU includes message 3 from the random access procedure, and N is an integer greater than 0. The N information units are encrypted using a first key, which is determined based on the first access layer (AS) security context of the terminal device. Alternatively, the message integrity authentication code (MAC-I) corresponding to message 3 is determined based on the N information units. The terminal device is in a radio resource control (RRS) inactive state.

[0283] The processing unit is used to decrypt the N information units or to verify the MAC-I based on the N information units.

[0284] When the communication device 1400 is used to implement the functions of a terminal device:

[0285] A processing unit is used to generate a Media Access Control (MAC) Protocol Data Unit (PDU); the MAC PDU includes a first MAC Service Data Unit (SDU) and N information units, wherein the information units are MAC SDUs or MAC Control Elements (CEs), the first MAC SDU includes message 3 from the random access procedure, and N is an integer greater than 0; wherein the N information units are encrypted and / or protected for integrity using a first key, the first key being determined based on the non-access stratum key of the terminal device; the terminal device is in a radio resource control idle state;

[0286] A communication unit is used to send the MAC PDU to the access network equipment.

[0287] When the communication device 1400 is used to implement the functions of an access network device:

[0288] A communication unit is used to receive a Media Access Control (MAC) Protocol Data Unit (PDU) from a terminal device. The MAC PDU includes a first MAC Service Data Unit (SDU) and N information units, where each information unit is a MAC SDU or a MAC Control Element (CE). The first MAC SDU includes a message 3 from the random access procedure, and N is an integer greater than 0. The N information units are encrypted and / or protected for integrity using a first key, which is determined based on the terminal device's non-access stratum key. The terminal device is in a radio resource control idle state.

[0289] The processing unit is used to decrypt and / or verify the integrity of the N information units.

[0290] When the communication device 1400 is used to implement the functions of core network equipment:

[0291] A communication unit is used to receive a first identifier from an access network device and N information units, wherein the information units are Media Access Control (MAC) Service Data Units (SDU) or MAC Control Elements (CE), and N is an integer greater than 0; wherein the N information units are encrypted and / or protected for integrity using a first key, and the first key is determined based on a non-access stratum key;

[0292] The processing unit is configured to decrypt the N information units according to a second key, and / or perform integrity verification on the N information units according to the second key, wherein the second key is determined based on the non-access stratum key corresponding to the first identifier; and send verification information to the access network device, wherein the verification information indicates whether decryption was successful and / or whether integrity verification was passed.

[0293] More detailed descriptions of the processing unit 1410 and the communication unit 1420 can be obtained directly from the relevant descriptions in the above method embodiments, and will not be repeated here.

[0294] It should be understood that the division of units in the above device is merely a logical functional division. In actual implementation, they can be fully or partially integrated into a single physical entity, or they can be physically separated. Furthermore, all units in the device can be implemented entirely through software calls from processing elements; all units can be implemented entirely in hardware; or some units can be implemented through software calls from processing elements, while others are implemented in hardware. For example, each unit can be a separate processing element, or it can be integrated into a chip within the device. Alternatively, it can be stored as a program in memory, called and executed by a processing element of the device. Moreover, these units can be fully or partially integrated together, or implemented independently. The processing element here can also be called a processor, which can be an integrated circuit with signal processing capabilities. In the implementation process, the operations or units described above can be implemented through integrated logic circuits in the processor element or through software calls from processing elements.

[0295] In one example, a unit in any of the above devices can be one or more integrated circuits configured to implement the methods described above, such as: one or more application-specific integrated circuits (ASICs), or one or more digital signal processors (DSPs), or one or more field-programmable gate arrays (FPGAs), or a combination of at least two of these forms of integrated circuits. As another example, when a unit in the device can be implemented in the form of a processing element scheduler, the processing element can be a processor, such as a general-purpose central processing unit (CPU), or other processor capable of calling programs. Furthermore, these units can be integrated together to implement a system-on-a-chip (SOC).

[0296] The receiving unit described above is an interface circuit of the device, used to receive signals from other devices. For example, when the device is implemented as a chip, the receiving unit is an interface circuit for the chip to receive signals from other chips or devices. The transmitting unit described above is an interface circuit of the device, used to transmit signals to other devices. For example, when the device is implemented as a chip, the transmitting unit is an interface circuit for the chip to transmit signals to other chips or devices.

[0297] As another possible product form, the terminal device or access network device of this application embodiment can be implemented by a general bus architecture. For ease of explanation, refer to FIG15, which is a schematic diagram of the structure of a communication device 1500 provided in an embodiment of this application. The communication device 1500 includes a processor 1501 and a transceiver 1502. The communication device 1500 can be a terminal device, or a chip or chip system therein; or, the communication device 1500 can be an access network device, or a chip or module therein. FIG15 only shows the main components of the communication device 1500. In addition to the processor 1501 and transceiver 1502, the communication device 1500 may further include a memory 1503 and input / output devices (not shown in the figure).

[0298] Optionally, the processor 1501 is mainly used to process communication protocols and communication data, control the entire communication device, execute software programs, and process the data of the software programs. The memory 1503 is mainly used to store software programs and data. The transceiver 1502 may include radio frequency (RF) circuitry and an antenna. The RF circuitry is mainly used for converting baseband signals to RF signals and processing RF signals. The antenna is mainly used for transmitting and receiving RF signals in the form of electromagnetic waves. Input / output devices, such as touchscreens, displays, and keyboards, are mainly used to receive user input data and output data to the user.

[0299] Optionally, the processor 1501, transceiver 1502, and memory 1503 can be connected via a communication bus.

[0300] When the communication device is powered on, the processor 1501 can read the software program in the memory 1503, interpret and execute the instructions of the software program, and process the data of the software program. When data needs to be transmitted wirelessly, the processor 1501 performs baseband processing on the data to be transmitted and outputs the baseband signal to the radio frequency (RF) circuit. The RF circuit processes the baseband signal and transmits the RF signal outward in the form of electromagnetic waves through the antenna. When data is sent to the communication device, the RF circuit receives the RF signal through the antenna, converts the RF signal into a baseband signal, and outputs the baseband signal to the processor 1501. The processor 1501 converts the baseband signal into data and processes the data.

[0301] In another implementation, the radio frequency circuitry and antenna can be set up independently of the processor that performs baseband processing. For example, in a distributed scenario, the radio frequency circuitry and antenna can be arranged remotely, independent of the communication device.

[0302] In some embodiments, those skilled in the art will recognize that the above-described communication device 1400 can be implemented in the form of the communication device 1500 shown in FIG15.

[0303] As an example, the function / implementation process of the processing unit 1410 in FIG14 can be implemented by the processor 1501 in the communication device 1500 shown in FIG15 calling computer execution instructions stored in the memory 1503. The function / implementation process of the communication unit 1420 in FIG14 can be implemented by the transceiver 1502 in the communication device 1500 shown in FIG15.

[0304] As another possible product form, the terminal device or access network device in this application may adopt the composition structure shown in FIG16, or include the components shown in FIG16. FIG16 is a schematic diagram of the composition of a communication device 1600 provided in this application.

[0305] As shown in Figure 16, the communication device 1600 includes at least one processor 1601. Optionally, the communication device also includes a communication interface 1602.

[0306] When the relevant program instructions are executed in the at least one processor 1601, the communication device 1600 can implement the methods and any possible designs provided in any of the foregoing embodiments. Alternatively, the processor 1601 can implement the methods and any possible designs provided in any of the foregoing embodiments through logic circuits or executable code instructions.

[0307] The communication interface 1602 can be used to receive program instructions and transmit them to the processor, or it can be used for communication device 1600 to communicate and interact with other communication devices, such as exchanging control signaling and / or service data. For example, the communication interface 1602 can be used to receive signals from other devices besides the communication device 1600 and transmit them to the processor 1601, or to send signals from the processor 1601 to other communication devices besides the communication device 1600.

[0308] Optionally, the communication interface 1602 can be a code and / or data read / write interface circuit, or the communication interface 1602 can be a signal transmission interface circuit between a communication processor and a transceiver, or a chip pin.

[0309] Optionally, the communication device 1600 may further include at least one memory 1603, which can be used to store the required program instructions and / or data. It should be noted that the memory 1603 may exist independently of the processor 1601 or may be integrated with the processor 1601. The memory 1603 may be located within or outside the communication device 1600, without limitation.

[0310] Optionally, the communication device 1600 may further include a power supply circuit 1604, which can be used to power the processor 1601. The power supply circuit 1604 may be located in the same chip as the processor 1601, or in a separate chip outside the chip containing the processor 1601.

[0311] Optionally, the communication device 1600 may also include a bus, through which the various parts of the communication device 1600 can be interconnected.

[0312] In some embodiments, those skilled in the art will recognize that the communication device 1400 shown in FIG14 can take the form of the communication device 1600 shown in FIG16 in terms of hardware implementation.

[0313] As an example, the function / implementation process of the processing unit 1410 in FIG14 can be implemented by the processor 1601 in the communication device 1600 shown in FIG16 calling the computer execution instructions stored in the memory 1603. The function / implementation process of the communication unit 1420 in FIG14 can be implemented by the communication interface 1602 in the communication device 1600 shown in FIG16.

[0314] It should be noted that the structure shown in Figure 16 does not constitute a specific limitation on the terminal device or access network device. For example, in other embodiments of this application, the terminal device or access network device may include more or fewer components than shown in the figure, or combine some components, or split some components, or have different component arrangements. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0315] When the aforementioned communication device is a chip applied to a terminal, the terminal chip implements the functions of the terminal in the above method embodiments. The terminal chip receives information from other modules (such as radio frequency modules or antennas) in the terminal, which is information sent to the terminal by the base station; or, the terminal chip sends information to other modules (such as radio frequency modules or antennas) in the terminal, which is information sent to the base station by the terminal.

[0316] When the aforementioned communication device is a module applied to a base station, the base station module implements the functions of the base station in the above method embodiments. The base station module receives information from other modules (such as radio frequency modules or antennas) in the base station, information sent by the terminal to the base station; or, the base station module sends information to other modules (such as radio frequency modules or antennas) in the base station, information sent by the base station to the terminal. Here, the base station module can be the baseband chip of the base station, or a DU (Digital Unit) or other modules. The DU can be a DU under an Open Radio Access Network (O-RAN) architecture.

[0317] It is understood that the processor in the embodiments of this application may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor may be a microprocessor or any conventional processor.

[0318] The method steps in the embodiments of this application can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Alternatively, the ASIC can reside in a base station or terminal. Of course, the processor and storage medium can also exist as discrete components in the base station or terminal.

[0319] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are performed entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user equipment, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video optical disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both types of storage media.

[0320] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0321] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, etc.) containing computer-usable program code.

[0322] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more blocks of the flowchart illustrations and / or one or more blocks of the block diagrams.

[0323] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means that implement the functions specified in one or more flowcharts and / or one or more block diagrams.

[0324] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A communication method, characterized in that, include: Generate Media Access Control (MAC) Protocol Data Unit (PDU); The MAC PDU includes a first MAC Service Data Unit (SDU) and N information units, where each information unit is a MAC SDU or a MAC Control Element (CE), and N is an integer greater than 0. The first MAC SDU includes message 3 from the random access procedure. The N information units are encrypted using a first key, which is determined based on the first access layer (AS) security context of the terminal device. Alternatively, the message integrity authentication code (MAC-I) corresponding to message 3 is determined based on the N information units. The terminal device is in a radio resource control inactive state. Send the MAC PDU to the access network equipment.

2. The method according to claim 1, characterized in that, The integrity protection key used to determine the MAC-I is the first key.

3. The method according to claim 1 or 2, characterized in that, The message integrity authentication code (MAC-I) corresponding to message 3 is determined based on the N information units, including: The MAC-I corresponding to message 3 is determined according to at least one of the following: The hash value determined based on at least one of the N information units; The first value is determined based on the M logical channel identifiers (LCIDs) corresponding to the M information units among the N information units, where M is an integer less than or equal to N.

4. The method according to claim 3, characterized in that, The first value is the sum of the M LCIDs; Alternatively, the first value may be a hash value determined based on the M LCIDs; Alternatively, the first value is a cyclic redundancy check value determined based on the M LCIDs.

5. The method according to any one of claims 1 to 4, characterized in that, Before generating the Media Access Control (MAC) Protocol Data Unit (PDU), the method further includes: The system receives first information from the access network device, the first information indicating that information during the random access process should be encrypted and / or protected for integrity.

6. The method according to any one of claims 1 to 5, characterized in that, The method further includes: The system receives second information from the access network device, the second information indicating a notification area RNA list or cell list based on the radio access network, the area corresponding to the RNA list or cell list being an area for encrypting and / or protecting the integrity of information during the random access process.

7. The method according to claim 6, characterized in that, The cell where the terminal device is located is in the RNA list or cell list.

8. The method according to any one of claims 1 to 7, characterized in that, The MAC-I is also determined based on the Channel State Information (CSI).

9. The method according to any one of claims 1 to 8, characterized in that, Before sending the MAC PDU to the access network device, the method further includes: Send a random access request message to the access network device.

10. A communication method, characterized in that, include: Receive Media Access Control (MAC) Protocol Data Unit (PDU) from the terminal device; The MAC PDU includes a first MAC Service Data Unit (SDU) and N information units, each information unit being a MAC SDU or a MAC Control Element (CE). The first MAC SDU includes message 3 from the random access procedure, where N is an integer greater than 0. The N information units are encrypted using a first key, which is determined based on the first access layer (AS) security context of the terminal device. Alternatively, the message integrity authentication code (MAC-I) corresponding to message 3 can be determined based on the N information units. The terminal device is in a radio resource control inactive state. Decrypt the N information units, or verify the MAC-I based on the N information units.

11. The method according to claim 10, characterized in that, The message 3 includes a first identifier of the terminal device; the decryption of the N information units includes: The second AS security context of the terminal device is determined based on the first identifier, and the second key is determined based on the second AS security context; The N information units are decrypted using the second key.

12. The method according to claim 10, characterized in that, The step of verifying the MAC-I based on the N information units includes: Determine the expected message integrity authentication code XMAC-I based on the N information units; If XMAC-I is the same as MAC-I, then the MAC-I verification passes; or if XMAC-I is different from MAC-I, then the MAC-I verification fails.

13. The method according to any one of claims 10 to 12, characterized in that, The integrity protection key used to determine the MAC-I is the first key.

14. The method according to any one of claims 10 to 13, characterized in that, The message integrity authentication code (MAC-I) corresponding to message 3 is determined based on the N information units, including: The MAC-I corresponding to message 3 is determined according to at least one of the following: The hash value determined based on at least one of the N information units; The first value is determined based on the M logical channel identifiers (LCIDs) corresponding to the M information units among the N information units, where M is an integer less than or equal to N.

15. The method according to claim 14, characterized in that, The first value is the sum of the M LCIDs; Alternatively, the first value may be a hash value determined based on the M LCIDs; Alternatively, the first value is a cyclic redundancy check value determined based on the M LCIDs.

16. The method according to any one of claims 10 to 15, characterized in that, The method further includes: Send a first message, which instructs that information during the random access process be encrypted and / or protected for integrity.

17. The method according to any one of claims 10 to 16, characterized in that, The method further includes: Send a second message, which indicates a notification area RNA list or cell list based on the radio access network, wherein the area corresponding to the RNA list or cell list is an area for encrypting and / or protecting the integrity of information during the random access process.

18. The method according to any one of claims 10 to 17, characterized in that, The MAC-I is also determined based on the Channel State Information (CSI).

19. A communication method, characterized in that, include: Generate Media Access Control (MAC) Protocol Data Unit (PDU); The MAC PDU includes a first MAC Service Data Unit (SDU) and N information units, wherein each information unit is a MAC SDU or a MAC Control Element (CE). The first MAC SDU includes message 3 from the random access procedure, and N is an integer greater than 0. The N information units are encrypted and / or protected for integrity using a first key, which is determined based on the non-access stratum key of the terminal device. The terminal device is in a radio resource control idle state. Send the MAC PDU to the access network equipment.

20. The method according to claim 19, characterized in that, Before generating the Media Access Control (MAC) Protocol Data Unit (PDU), the method further includes: Receive a first indication message from the access network device, the first indication message indicating that information during the random access process should be encrypted and / or protected for integrity.

21. The method according to claim 19 or 20, characterized in that, The method further includes: Receive a second indication message, which indicates a core network device set or a tracking area corresponding to the core network device set, wherein the tracking area corresponding to the core network device set is the effective area of ​​the first key.

22. The method according to claim 21, characterized in that, The message 3 includes a first identifier of the terminal device, which is determined based on the identifier of the core network device set.

23. A communication method, characterized in that, include: Receive Media Access Control (MAC) Protocol Data Unit (PDU) from the terminal device; The MAC PDU includes a first MAC Service Data Unit (SDU) and N information units, wherein each information unit is a MAC SDU or a MAC Control Element (CE). The first MAC SDU includes message 3 from the random access procedure, and N is an integer greater than 0. The N information units are encrypted and / or protected for integrity using a first key, which is determined based on the non-access stratum key of the terminal device. The terminal device is in a radio resource control idle state. Decrypt and / or verify the integrity of the N information units.

24. The method according to claim 23, characterized in that, The message 3 includes a first identifier of the terminal device; the decryption and / or integrity verification of the N information units includes: Send the first identifier to the core network device and receive the second key from the core network device, wherein the second key is determined based on the non-access stratum key corresponding to the first identifier; The N information units are decrypted using the second key, and / or the integrity of the N information units is verified using the second key.

25. A communication device, characterized in that, include: The processing unit is used to generate Media Access Control (MAC) Protocol Data Units (PDUs). The MAC PDU includes a first MAC Service Data Unit (SDU) and N information units, where each information unit is a MAC SDU or a MAC Control Element (CE), and N is an integer greater than 0. The first MAC SDU includes message 3 from the random access procedure. The N information units are encrypted using a first key, which is determined based on the first access layer (AS) security context of the terminal device. Alternatively, the message integrity authentication code (MAC-I) corresponding to message 3 is determined based on the N information units. The terminal device is in a radio resource control inactive state. A communication unit is used to send the MAC PDU to the access network equipment.

26. A communication device, characterized in that, include: The communication unit is used to receive Media Access Control (MAC) Protocol Data Unit (PDU) from the terminal device. The MAC PDU includes a first MAC Service Data Unit (SDU) and N information units, each information unit being a MAC SDU or a MAC Control Element (CE). The first MAC SDU includes message 3 from the random access procedure, where N is an integer greater than 0. The N information units are encrypted using a first key, which is determined based on the first access layer (AS) security context of the terminal device. Alternatively, the message integrity authentication code (MAC-I) corresponding to message 3 can be determined based on the N information units. The terminal device is in a radio resource control inactive state. The processing unit is used to decrypt the N information units or to verify the MAC-I based on the N information units.

27. A communication device, characterized in that, include: The processing unit is used to generate Media Access Control (MAC) Protocol Data Units (PDUs). The MAC PDU includes a first MAC Service Data Unit (SDU) and N information units, wherein each information unit is a MAC SDU or a MAC Control Element (CE). The first MAC SDU includes message 3 from the random access procedure, and N is an integer greater than 0. The N information units are encrypted and / or protected for integrity using a first key, which is determined based on the non-access stratum key of the terminal device. The terminal device is in a radio resource control idle state. A communication unit is used to send the MAC PDU to the access network equipment.

28. A communication device, characterized in that, include: The communication unit is used to receive Media Access Control (MAC) Protocol Data Unit (PDU) from the terminal device. The MAC PDU includes a first MAC Service Data Unit (SDU) and N information units, wherein each information unit is a MAC SDU or a MAC Control Element (CE). The first MAC SDU includes message 3 from the random access procedure, and N is an integer greater than 0. The N information units are encrypted and / or protected for integrity using a first key, which is determined based on the non-access stratum key of the terminal device. The terminal device is in a radio resource control idle state. The processing unit is used to decrypt and / or verify the integrity of the N information units.

29. A communication device, characterized in that, Includes a processor; the processor is configured to execute a computer program or instructions that cause the communication device to implement the method described in any one of claims 1 to 24.

30. A computer program product, characterized in that, When the computer reads and executes the computer program product, the method described in any one of claims 1 to 24 is performed.

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