Security perception method, device, computer-readable storage medium and chip

Abstract

The present disclosure provides a security perception method, device, computer-readable storage medium and chip. The method includes an initiator device sending a security perception request to a responder device and receiving a response to the security perception request from the responder device. The response includes a first sequence verification code and an initial value of a long training field (LTF) counter. The method also includes receiving multiple null data packets (NDPs) for security perception from the responder device. Multiple NDPs each include a scrambled LTF sequence. The method also includes descrambling the scrambled LTF sequences in multiple NDPs based on a derived key shared between the initiator device and the responder device, a first sequence verification code and an initial value of the LTF counter to obtain multiple descrambled LTF sequences. The method also includes determining channel state information (CSI) based on multiple descrambled LTF sequences. The method also includes performing security perception based on CSI. In this way, security and privacy protection for users of wireless perception is achieved.

Description

Technical Field

[0001] The present disclosure relates to the field of communications, and more particularly, to a method, a device, a computer-readable storage medium, and a chip for security awareness. Background Art

[0002] With the development of communication technology, various wireless communication devices have been deployed in large numbers in people's daily lives. These wireless communication devices can include mobile phones, personal computers, smart home devices, wireless sensors, and wireless routers. The important features of these devices are that they are large in number, low in price, and very close to the user. In a common home environment, there are often more than ten or even hundreds of wireless communication devices surrounding the user. During the process of communicating wirelessly, these devices can sense the interference of surrounding user actions on the wireless channel, and use the measurement of such interference to sense the surrounding user actions. This type of technology is also called wireless sensing technology. This technology can be widely used in intrusion detection, elderly care, gesture recognition, respiratory sleep monitoring, and indoor population counting.

[0003] Wireless sensing technology measures the interference of wireless channels in the form of channel state information (CSI). Since CSI can be obtained by any receiving device, it is easy for attackers to infer the user's actions by obtaining CSI, thereby easily leaking the user's behavior privacy. Summary of the invention

[0004] Example embodiments of the present disclosure provide a solution for security awareness.

[0005] In a first aspect of the present disclosure, a method for security perception implemented at an initiator device is provided. The method includes the initiator device sending a security perception request to the responder device. The method also includes the initiator device receiving a response to the security perception request from the responder device, the response including a first sequence verification code and an initial value of a long training field counter. The method also includes the initiator device receiving a plurality of empty data packets for security perception from the responder device, each of the plurality of empty data packets including a scrambled long training field sequence. The method also includes the initiator device descrambling the scrambled long training field sequences in the plurality of empty data packets based on a derived key shared between the initiator device and the responder device, the first sequence verification code and the initial value of the long training field counter to obtain a plurality of descrambled long training field sequences. The method also includes the initiator device determining the channel state information of the channel between the responder device and the initiator device based on the plurality of descrambled long training field sequences. The method also includes the initiator device performing security perception based on the channel state information.

[0006] In some embodiments, descrambling the scrambled long training field sequences in a plurality of null data packets comprises: the initiator device determines the index of the descrambling sequence and the linear prediction coefficient set based on the derived key, the first sequence verification code, and the initial value of the long training field counter; descrambling the first scrambled long training field sequence in the plurality of null data packets using the descrambling sequence to obtain the first descrambled long training field sequence; and descrambling subsequent scrambled long training field sequences in the plurality of null data packets using the linear prediction coefficient set and the first descrambled long training field sequence to obtain subsequent descrambled long training field sequences.

[0007] In some embodiments, descrambling subsequent scrambled long training field sequences in a plurality of null data packets to obtain subsequent descrambled long training field sequences comprises: obtaining an estimate of the (n+1)th descrambled long training field sequence based on:

[0008]

[0009] in represents the estimated value of the n+1th descrambled long training field sequence, a i represents the i-th linear prediction coefficient in the linear prediction coefficient set, p represents the number of elements in the linear prediction coefficient set, 7≤p≤15, 1≤i≤p, 1≤n≤N-1, and N represents the number of the multiple empty data packets.

[0010] In some embodiments, the initiator device sending a security awareness request to the responder device includes: the initiator device sending an initial fine timing measurement request frame to the responder device, wherein a trigger field in the initial fine timing measurement request frame is set to a predefined value, and the predefined value indicates a security awareness request.

[0011] In some embodiments, the method further includes: before receiving each empty data packet in a plurality of empty data packets, the initiator device updates the initial value of the long training field counter in response to receiving a control frame associated with the corresponding empty data packet from the responder device to obtain an updated counter value, the control frame including a second sequence verification code; based on the derived key and the updated counter value, generating an updated first sequence verification code; and if the updated first sequence verification code is different from the second sequence verification code, the initiator device resending the security awareness request to the responder device.

[0012] In a second aspect of the present disclosure, a method for security perception implemented at a responder device is provided. The method includes the responder device receiving a security perception request from an initiator device. The method also includes the responder device sending a response to the security perception request to the initiator device. The response includes a first sequence verification code and an initial value of a long training field counter, which is used to descramble multiple scrambled long training field sequences. The method also includes the responder device scrambling multiple long training field sequences based on a derived key shared between the initiator device and the responder device, and the initial value of the long training field counter to obtain multiple scrambled long training field sequences. The method also includes the responder device sending multiple empty data packets for security perception to the initiator device. The multiple empty data packets each include one of the multiple scrambled long training field sequences.

[0013] In some embodiments, scrambling a plurality of long training field sequences to obtain a plurality of scrambled long training field sequences comprises: the responder device determines, based on a derived key and an initial value of a long training field counter, an index of a scrambling sequence and a set of linear prediction coefficients; scrambling a first long training field sequence of the plurality of long training field sequences using the scrambling sequence to obtain a first scrambled long training field sequence; and scrambling subsequent long training field sequences of the plurality of long training field sequences using the set of linear prediction coefficients and the first scrambled long training field sequence to obtain subsequent scrambled long training field sequences.

[0014] In some embodiments, scrambling a subsequent long training field sequence in a plurality of long training field sequences to obtain a subsequent scrambled long training field sequence comprises:

[0015] An estimate of the n+1th scrambled long training field sequence is obtained based on:

[0016]

[0017] in represents the estimated value of the n+1th scrambled long training field sequence, a i represents the i-th linear prediction coefficient in the linear prediction coefficient set, p represents the number of elements in the linear prediction coefficient set, 7≤p≤15, 1≤i≤p, 1≤n≤N-1, and N represents the number of the multiple empty data packets.

[0018] In some embodiments, the responder device receiving the security-aware request from the initiator device includes: the responder device receiving an initial fine timing measurement request frame from the initiator device, wherein a trigger field in the initial fine timing measurement request frame is set to a predefined value, and the predefined value indicates a security-aware request.

[0019] In some embodiments, the method further includes: before sending each empty data packet in a plurality of empty data packets, the responder device updates the initial value of the long training field counter in response to a control frame associated with the corresponding empty data packet to be sent to the initiator device to obtain an updated counter value; based on the derived key and the updated counter value, generates an updated first sequence verification code as a second sequence verification code; and the responder device sends a control frame to the initiator device, the control frame including the second sequence verification code, for the initiator device to determine whether to resend the security awareness request to the responder device.

[0020] In a third aspect of the present disclosure, an initiator device is provided. The initiator device includes a sending unit, a receiving unit, a descrambling unit, a determining unit, and a sensing unit. The sending unit is configured to send a security sensing request to a responder device. The receiving unit is configured to receive a response to the security sensing request from the responder device, the response including a first sequence verification code and an initial value of a long training field counter. The receiving unit is configured to receive a plurality of empty data packets for security sensing from the responder device. The plurality of empty data packets each include a scrambled long training field sequence. The descrambling unit is configured to descramble the scrambled long training field sequences in the plurality of empty data packets based on a derived key shared between the initiator device and the responder device, the first sequence verification code, and the initial value of the long training field counter to obtain a plurality of descrambled long training field sequences. The determining unit is configured to determine the channel state information of the channel between the responder device and the initiator device based on the plurality of descrambled long training field sequences. The sensing unit is configured to perform security sensing based on the channel state information.

[0021] In some embodiments, the descrambling unit is further configured to: determine the index of the descrambling sequence and the linear prediction coefficient set based on the derived key, the first sequence verification code and the initial value of the long training field counter; use the descrambling sequence to descramble the first scrambled long training field sequence in multiple empty data packets to obtain the first descrambled long training field sequence; and use the linear prediction coefficient set and the first descrambled long training field sequence to descramble subsequent scrambled long training field sequences in multiple empty data packets to obtain subsequent descrambled long training field sequences.

[0022] In some embodiments, the descrambling unit is further configured to obtain an estimate of the n+1th descrambled long training field sequence based on:

[0023]

[0024] in represents the estimated value of the n+1th descrambled long training field sequence, a irepresents the i-th linear prediction coefficient in the linear prediction coefficient set, p represents the number of elements in the linear prediction coefficient set, 7≤p≤15, 1≤i≤p, 1≤n≤N-1, and N represents the number of the multiple empty data packets.

[0025] In some embodiments, the sending unit is further configured to: send an initial fine timing measurement request frame to the responder device, wherein a trigger field in the initial fine timing measurement request frame is set to a predefined value, and the predefined value indicates a security awareness request.

[0026] In some embodiments, the receiving unit is further configured to: before receiving each empty data packet in a plurality of empty data packets, receive a control frame associated with the corresponding empty data packet from a responder device; and the device further includes an updating unit, configured to: update an initial value of a long training field counter in response to receiving a control frame associated with the corresponding empty data packet from the responder device to obtain an updated counter value, the control frame including a second sequence verification code; generate an updated first sequence verification code based on a derived key and the updated counter value; and the sending unit is further configured to: if the updated first sequence verification code is different from the second sequence verification code, resend a security awareness request to the responder device.

[0027] In a fourth aspect of the present disclosure, a responder device is provided. The responder device includes a receiving unit, a sending unit and a scrambling unit. The receiving unit is configured to receive a security perception request from an initiator device. The sending unit is configured to send a response to the security perception request to the initiator device, the response including a first sequence verification code and an initial value of a long training field counter, for descrambling a plurality of scrambled long training field sequences. The scrambling unit is configured so that the responder device scrambles a plurality of long training field sequences based on a derived key shared between the initiator device and the responder device, and an initial value of the long training field counter to obtain a plurality of scrambled long training field sequences. The sending unit is further configured to send a plurality of empty data packets for security perception to the initiator device, each of the plurality of empty data packets including one of a plurality of scrambled long training field sequences.

[0028] In some embodiments, the scrambling unit is further configured to: determine an index of a scrambling sequence and a set of linear prediction coefficients based on a derived key and an initial value of a long training field counter; scramble a first long training field sequence among a plurality of long training field sequences using the scrambling sequence to obtain a first scrambled long training field sequence; and scramble subsequent long training field sequences among a plurality of long training field sequences using the set of linear prediction coefficients and the first scrambled long training field sequence to obtain subsequent scrambled long training field sequences.

[0029] In some embodiments, the scrambling unit is further configured to obtain an estimate of the n+1th scrambled long training field sequence based on:

[0030]

[0031] in represents the estimated value of the n+1th scrambled long training field sequence, a i represents the i-th linear prediction coefficient in the linear prediction coefficient set, p represents the number of elements in the linear prediction coefficient set, 7≤p≤15, 1≤i≤p, 1≤n≤N-1, and N represents the number of the multiple empty data packets.

[0032] In some embodiments, the receiving unit is further configured to receive an initial fine timing measurement request frame from the initiator device, the trigger field in the initial fine timing measurement request frame being set to a predefined value, the predefined value indicating a security awareness request.

[0033] In some embodiments, the device further includes an updating unit. The updating unit is configured to: before sending each of the plurality of empty data packets, in response to a control frame associated with the corresponding empty data packet to be sent to the initiator device, update the initial value of the long training field counter to obtain an updated counter value; based on the derived key and the updated counter value, generate an updated first sequence verification code as the second sequence verification code. In such an embodiment, the receiving unit is further configured to send a control frame to the initiator device, the control frame including the second sequence verification code, for the initiator device to determine whether to resend the security awareness request to the responder device.

[0034] In a fifth aspect of the present disclosure, a computer-readable storage medium is provided, wherein a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the method according to the first aspect of the present disclosure is implemented.

[0035] In a sixth aspect of the present disclosure, a computer-readable storage medium is provided, wherein a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the method according to the second aspect of the present disclosure is implemented.

[0036] In a seventh aspect of the present disclosure, a chip is provided. The chip includes a processing circuit and a communication interface. The processing circuit is configured to execute the method of the first aspect of the present disclosure.

[0037] In an eighth aspect of the present disclosure, a chip is provided. The chip includes a processing circuit and a communication interface. The processing circuit is configured to execute the method of the second aspect of the present disclosure.

[0038] In a ninth aspect of the present disclosure, a computer program product is provided, which includes machine executable instructions, which, when executed by an initiator device, cause the initiator device to perform the method according to the first aspect of the present disclosure.

[0039] In a tenth aspect of the present disclosure, a computer program product is provided, which includes machine executable instructions, which, when executed by a responder device, cause the responder device to perform the method according to the second aspect of the present disclosure.

[0040] In an eleventh aspect of the present disclosure, an initiator device is provided, which includes the components described in the third aspect or any implementation thereof.

[0041] In a twelfth aspect of the present disclosure, a responder device is provided, which includes the components described in the fourth aspect or any implementation manner thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The features, advantages and other aspects of various implementations of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Several implementations of the present disclosure are shown here in an exemplary and non-limiting manner. In the accompanying drawings:

[0043] Figure 1 A schematic block diagram showing a communication environment in which embodiments of the present disclosure may be implemented;

[0044] Figure 2 A schematic diagram showing an application scenario of an embodiment of the present disclosure;

[0045] Figure 3 A signaling interaction diagram for a security awareness process according to some embodiments of the present disclosure is shown;

[0046] Figure 4A A schematic diagram showing a frame format of an initial fine timing measurement request frame according to some embodiments of the present disclosure;

[0047] Figure 4B Shows Figure 4A A schematic diagram of the format of the ranging parameter field shown;

[0048] Figure 4C Shows Figure 4B A schematic diagram of the format of the ranging parameter field shown;

[0049] Figure 4D A schematic diagram showing the format of a secure long training field parameter field according to some embodiments of the present disclosure;

[0050] Figure 4EA schematic diagram showing the format of the site information field of a null data packet announcement frame according to some embodiments of the present disclosure;

[0051] Figure 5 shows a waveform diagram of CSI time domain data corresponding to a walking action according to some embodiments of the present disclosure;

[0052] Figure 6 A time domain waveform diagram showing an estimated value of a scrambled long training field sequence according to some embodiments of the present disclosure;

[0053] Figure 7 Shows Figure 5 The spectrum diagram of the CSI time domain data shown and Figure 6 A spectrum diagram of an estimate of a scrambled long training field sequence is shown;

[0054] Figure 8 A flowchart showing an example method for security awareness according to some embodiments of the present disclosure is shown;

[0055] Fig. 9 A flowchart showing an example method for security awareness according to other embodiments of the present disclosure is shown;

[0056] Fig.10 A schematic block diagram of a communication device according to some embodiments of the present disclosure is shown;

[0057] Fig.11 A schematic block diagram showing a communication device according to some other embodiments of the present disclosure; and

[0058] Fig.12 A simplified block diagram of an example apparatus according to some embodiments of the present disclosure is shown.

[0059] In the various drawings, the same or similar reference numbers denote the same or similar elements. DETAILED DESCRIPTION

[0060] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as being limited to the embodiments described herein, which are instead provided for a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not intended to limit the scope of protection of the present disclosure.

[0061] In the description of the embodiments of the present disclosure, the term "including" and similar terms should be understood as open inclusion, that is, "including but not limited to". The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other explicit and implicit definitions may also be included below. Expressions similar to "at least one of A, B, and C" or "at least one of A, B, or C" should be understood as any of the following: at least one A; at least one B; at least one C; at least one A and at least one B; at least one A and at least one C; at least one B and at least one C; at least one A, at least one B, and at least one C. The above is illustrated by taking A, B, and C as an example. When there are more elements in the expression, the meaning of the expression can be obtained according to the above rules.

[0062] The embodiments of the present disclosure may be applied to any appropriate wireless communication system. The wireless communication system may be, for example, a wide area network system or a wireless local area network (WLAN) system. The wireless communication system may support a variety of WLAN communication protocols, such as 802.11az in the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series of protocols or any of the future IEEE 802.11 series of protocols. For the purpose of illustration, the embodiments of the present disclosure will be described below with the WLAN system as the background. However, it should be understood that the embodiments of the present disclosure are not limited to being applied to WLAN systems, but may be applied to any other communication systems with similar problems.

[0063] Figure 1 The schematic block diagram of a communication environment 100 in which the embodiments of the present disclosure may be implemented is shown. As shown in the figure, the communication environment 100 includes an initiator device 110, a responder device 120 and a detection target 130.

[0064] The initiator device 110 is also called an initiator station (ISTA), which refers to any device that can initiate a security awareness request and perform security awareness based on a wireless signal received from the responder device 120. The initiator device 110 can be a terminal device with a Wi-Fi communication function, such as a mobile phone, a tablet computer, a personal digital assistant, a wireless sensor, a printer, a smart TV, a smart light bulb, etc.

[0065] The responder device 120 is also called a responder station (RSTA), which refers to any device that can respond to the security awareness request and assist the responder device 120 in performing security awareness. The responder device 120 can be a network device with Wi-Fi communication function, such as a base station, a router, a gateway, a repeater, a server, a switch or a bridge.

[0066] It should be understood that although the initiator device 110 and the responder device 120 are Figure 1 Although shown as separate physical devices, in other embodiments both may be deployed in a single physical device.

[0067] The detection target 130 refers to any object whose action or behavior is sensed by the initiator device 110, such as a person, an animal, etc.

[0068] The initiator device 110 and the responder device 120 can communicate to wirelessly sense the action of the detection target 130. Specifically, the wireless signal received by the initiator device 110 includes a superimposed signal after the direct signal 140 and the reflected signal 150 reflected by the detection target 130 are superimposed. When the detection target 130 moves, the reflected signal 150 will change. In this way, the superimposed signal received by the initiator device 110 will also change accordingly. At this time, the initiator device 110 will detect that the wireless channel between the initiator device 110 and the responder device 120 has changed. Generally, the wireless channel can be quantified as CSI in the communication protocol. The change of the wireless channel is manifested as the change of the amplitude and phase of the CSI. The initiator device 110 can perform wireless perception based on the change of CSI over time. For example, the initiator device 110 can perceive whether the detection target 130 is moving and what specific action it is taking based on the change of CSI over time.

[0069] Understandably, Figure 1 The number of initiator devices 110 and responder devices 120 shown in the figure is only an example and is not intended to impose any limitation. According to actual needs, the communication environment 100 may include any appropriate number of initiator devices 110 and responder devices 120. For example, when the embodiments of the present disclosure are applied to a home environment, the communication environment 100 may include multiple initiator devices. In this case, the responder device 120 may communicate with multiple initiator devices to monitor the entire home environment. Figure 2 Describe this application scenario.

[0070] Figure 2A schematic diagram of an application scenario of some embodiments of the present disclosure in a home environment 200 is shown. As shown in the figure, the home environment 200 includes a living room 210, a bathroom 220, a kitchen 230, and bedrooms 240, 250, and 260. The responder device 120 in the living room 210 can communicate with the initiator device 110-1 in the living room to sense the action of the detection target (not shown) in the living room 210. The responder device 120 can communicate with the initiator device 110-2 in the bathroom 220 and the initiator device 110-3 in the kitchen 230 to sense the action of the detection target (not shown) in the bathroom 220 and the kitchen 230. The responder device 120 can also communicate with the initiator devices 110-4 to 110-6 in the bedrooms 240 to 260 to detect the sleeping status of the detection targets (not shown) in the bedrooms 240 to 260.

[0071] In addition, the attacker device 110 - 7 (also referred to as an illegal device) is also present in the bedroom 240. Although the attacker device 110 - 7 can receive wireless signals from the responder device 120, it cannot monitor the sleep status of the detection target in the bedroom 240 based on the received wireless signals.

[0072] The following will refer to Figures 3 to 7 The embodiments of the present disclosure are described in detail.

[0073] Figure 3 FIG. 3 shows a signaling interaction diagram for a security awareness process 300 according to some embodiments of the present disclosure. For the purpose of discussion, reference will be made to FIG. Figure 1 The security awareness process 300 is described with reference to the various elements shown in FIG. However, it should be understood that the security awareness process 300 may also be performed between an initiator device and a responder device in any other communication scenario. For example, the security awareness process 300 may also be applied to Figure 2 Between any one of the initiator devices 110 - 1 to 110 - 6 and the responder device 120 in the illustrated home environment 200 .

[0074] like Figure 3 As shown, at 320, the initiator device 110 sends a security awareness request to the responder device 120. In some embodiments, the initiator device 110 may send an initial fine timing measurement request (IFTMR) frame to the responder device 120. The trigger field in the IFTMR frame may be set to a predefined value, which may indicate a security awareness request.

[0075] Figure 4A FIG. 2 is a schematic diagram showing the frame format of an IFTMR frame. Figure 4AAs shown, the IFTMR frame 400 includes at least a trigger field 410 and a ranging parameters field 420. The meaning of the value of the trigger field 410 is shown in Table 1 below.

[0076] Table 1

[0077]

[0078] In the prior art, the values ​​5-255 of the trigger field 410 are reserved. In some embodiments of the present disclosure, any one of the values ​​5-255 can be predefined to indicate a security awareness request. In other words, the value of the trigger field in the IFTMR frame can be set to one of 5-255 to indicate that the initiator site requests the responder site to start a security awareness process. For example, as shown in Table 1, when the value of the trigger field is set to 5, it indicates that the initiator site requests the responder site to start a security awareness process. Accordingly, the values ​​6-255 are reserved. Among them, the meaning of the "reserved" value means that the function and use of the value are not defined at this stage, and there may be other meanings, which will be defined in the future.

[0079] It should be understood that using the value 5 of the trigger field 410 to indicate a security awareness request is merely an example. In other embodiments, any one of the values ​​6-255 may be used to indicate a security awareness request. In addition, in terms of expression, the meaning of the value of the trigger field 410 used to indicate a security awareness request may be different from that shown in Table 1, as long as it can indicate a security awareness request or a wireless awareness request. For example, the value 5 of the trigger field 410 may be defined as the initiator site requesting the responder site to initiate a security awareness measurement process, or the initiator site requesting the responder site to initiate a wireless awareness process, and so on.

[0080] Figure 4B Shows Figure 4A FIG. 4 is a schematic diagram of the format of the ranging parameter field 420. Figure 4B As shown, the ranging parameter field 420 includes a ranging parameter subfield 430 . Figure 4C Shows Figure 4B FIG. 4 is a schematic diagram of the format of the ranging parameter subfield 430. Figure 4C As shown, the ranging parameter subfield 430 includes a secure LTF support (Secure LTF Support) subfield 431. In an embodiment in which a security awareness request is sent by sending the IFTMR frame 400, the responder device 120 may set the value of the secure LTF support subfield 431 to a predefined value to indicate that the responder device 120 supports CSI measurement based on the scrambled LTF sequence. The predefined value may be 1, for example.

[0081] Return to Figure 3 At 330, after successfully receiving the security awareness request, the responder device 120 sends a response to the security awareness request to the initiator device 110. The response to the security awareness request includes a first sequence authentication code (Sequence Authentication Code, SAC) and an initial value of a long training field (Long Training Field, LTF) counter.

[0082] In some embodiments, optionally, if dot11SecureLTFImplemented in the responder device 120 is set to 1, indicating that the responder device 120 agrees to start the security awareness process, the responder device 120 sends a response to the security awareness request to the initiator device 110.

[0083] In some embodiments, optionally, after successfully receiving the security awareness request, the responder device 120 may first send a positive confirmation (ACK) to the initiator device 110 ( Figure 3 After sending the ACK, the responder device 120 sends a response to the security awareness request to the initiator device 110.

[0084] In some embodiments, responder device 120 may send a response to the security-aware request by sending an Initial Fine Timing Measurement (IFTM) frame to initiator device 110. In such embodiments, the IFTM frame may include a Secure LTF Parameters field. Figure 4D FIG. 4 is a schematic diagram showing the format of the security LTF parameter field 440. Figure 4D As shown, the secure LTF parameter field 440 includes an LTF generation SAC (LTFGeneration SAC) subfield 441 and a secure LTF counter (Secure LTF Counter) subfield 442. The LTF generation SAC field is used to carry the first SAC as described above, and the secure LTF counter subfield 442 is used to carry the initial value of the LTF counter.

[0085] Before sending a response to the security awareness request, the responder device 120 may determine the value of the security LTF counter subfield 442 and the value of the LTF generation SAC subfield 441. In some embodiments, the responder device 120 may initialize the value of the security LTF counter subfield 442 to 0 (e.g., 48 bits). In other words, the initial value of the LTF counter may be 0. It is understood that the initial value of the LTF counter may be any appropriate value, and the scope of the present disclosure is not limited in this respect.

[0086] In addition, in some embodiments, the responder device 120 may determine the value of the LTF generation SAC subfield 441, i.e., the first SAC, based on the initial value of the LTF counter and the derived key shared between the initiator device 110 and the responder device 120. As an example, the responder device 120 may generate the value of the LTF generation SAC subfield 441 based on the hash function shown in the following formula (1):

[0087] SAC||Secure-LTF-bits-R2I||LPC-type=KDF-Hash-Length(Secure-LTF-key-seed, "Secure LTF Extension", Secure-LTF-Counter) (1) wherein SAC represents the value of the LTF generation SAC subfield 441 (i.e., the first SAC, with a length of 16 bits), Secure-LTF-bits-R2I represents the scrambling sequence, LPC-type represents the index of the linear prediction coefficient (LPC) set, Secure-LTF-key-seed represents the derived key shared between the initiator device 110 and the responder device 120, Secure LTF Extension indicates that the sum of the lengths of SAC, Secure-LTF-bits-R2I and LPC-type is extended to a predetermined length (e.g., 272 bits) by padding with zeros, and Secure-LTF-Counter represents the initial value of the secure LTF counter subfield 442. Secure-LTF-bits-R2I and LPC-type can be used to scramble the LTF sequence, which will be described in detail below.

[0088] It should be understood that the above formula (1) is only an example for determining the first SAC. The responder device 120 may determine the first SAC using any appropriate algorithm based on the initial value of the LTF counter and the derived key.

[0089] In addition, the Secure LTF Parameters field may also include a Secure LTF Request subfield ( Figure 4D In order to indicate to the initiator device 110 that the responder device 120 agrees to start the security awareness process, the responder device 120 may set the value of the security LTF request subfield to a predefined value. The predefined value may be 1, for example.

[0090] Continue to refer Figure 3In some embodiments, in order to determine the derived key Secure-LTF-key-seed, at 310, the initiator device 110 and the responder device 120 may exchange a pairwise transient key security association (PTKSA) using a conventional four-way handshake process. Then, the initiator device 110 and the responder device 120 may each determine a key derivation key (KDK) based on the PTKSA. Furthermore, the initiator device 110 and the responder device 120 may each determine the derived key Secure-LTF-key-seed based on the KDK. For example, the responder device 120 may generate the derived key Secure-LTF-key-seed based on the hash function shown in the following formula (2):

[0091] Secure-LTF-key-seed=HMAC-Hash(KDK,"Secure LTF key seed") (2)

[0092] In some embodiments, optionally, after successfully receiving a response to the security awareness request, the initiator device 110 may send an ACK (ACK_ACK) to the responder device 120. Figure 3 In addition, the initiator device 110 can obtain the initial value of the first SAC and the LTF counter from the response to the security awareness request and store them locally. In addition, the initiator device 110 can use the initial value of the LTF counter as the number of received NDPs (i.e., the number of scrambled LTF sequences) to determine whether the NDP is lost. This will be described in detail below.

[0093] In some embodiments, the initiator device 110 may calculate the SAC locally based on the initial value of the LTF counter obtained from the response to the security perception request and the shared derived key, for example, using the above formula (1). Subsequently, the initiator device 110 may compare the calculated SAC with the first SAC obtained from the response to the security perception request. If the two are different, it indicates that the obtained first SAC is not generated based on the key shared between the initiator device 110 and the responder device 120. As a result, the initiator device 110 can determine that the responder device 120 is an illegal terminal, and then the security perception process can be terminated.

[0094] After sending the response to the security awareness request, at 340, the responder device 120 scrambles the plurality of LTF sequences based on the derived key shared between the initiator device 110 and the responder device 120 and the initial value of the long training field sequence counter to obtain a plurality of scrambled LTF sequences.

[0095] It can be understood that by scrambling the LTF sequence, the elements in the original LTF sequence are randomly distributed in the time domain. Therefore, scrambling the LTF sequence is also called randomizing the LTF sequence, and the scrambled LTF sequence is also called the randomized LTF sequence. Correspondingly, descrambling the LTF sequence is also called de-randomizing the LTF sequence, and the descrambled LTF sequence is also called the de-randomized LTF sequence.

[0096] At 350, the responder device 120 sends a plurality of Null Data Packets (NDPs) for security awareness to the initiator device 110. Each NDP includes one scrambled LTF sequence among a plurality of scrambled LTF sequences.

[0097] In some embodiments, before sending each of the multiple NDPs, the responder device 120 may send a control frame associated with the corresponding NDP to the initiator device 110. The control frame may indicate that the responder device 120 is about to send an NDP to the initiator device 110. An example of the control frame may include a Null Data Packet Announcement (NDPA) frame.

[0098] In some embodiments, in response to sending a control frame to the initiator device 110, the responder device 120 may update the initial value of the LTF sequence counter to obtain an updated timer value. In other words, before each control frame is sent, the responder device 120 may update the initial value of the LTF sequence counter. For example, the responder device 120 may update the initial value of the LTF sequence counter by increasing the initial value of the LTF sequence counter by 1. Furthermore, the responder device 120 may generate an updated first SAC based on a derived key shared between the initiator device 110 and the responder device 120 and the updated timer value. For example, the responder device 120 may generate an updated first SAC based on the formula (1) described above. Subsequently, the responder device 120 may send a control frame to the initiator device 110, the control frame including the updated first SAC. Hereinafter, the first SAC updated by the responder device 120 is also referred to as the second SAC.

[0099] In an embodiment in which an NDPA frame is used as a control frame, the NDPA frame may include a station information (STA Info) field. Figure 4E FIG. 4 is a schematic diagram showing the format of the site information field 450 of the NDPA frame. Figure 4E As shown, the site information field 450 includes a SAC subfield 451, which is used to carry the updated first SAC (ie, the second SAC).

[0100] After each time the initiator device 110 receives a control frame, the initial value of the LTF counter obtained from the response to the security awareness request can be updated to obtain an updated counter value. In other words, after each time the initiator device 110 receives a control frame, the number of received NDPs can be updated. Then, the initiator device 110 can generate an updated first SAC based on the derived key shared between the initiator device 110 and the responder device 120 and the updated timer value. For example, the initiator device 110 can generate an updated first SAC based on the formula (1) described above. Subsequently, the initiator device 110 can compare the updated first SAC generated by itself with the second SAC obtained from the control frame. If the updated first SAC is different from the second SAC, the initiator device 110 can determine that the NDP is lost. Furthermore, the initiator device 110 can resend the security awareness request to the responder device 120.

[0101] In addition, in some embodiments, the initiator device 110 may also utilize the number of received NDPs to facilitate correct descrambling of the scrambled LTF sequence in the received NDP. This will also be described in detail below in conjunction with the algorithm for determining the linear prediction coefficient set.

[0102] Continue to refer Figure 3 After receiving multiple NDPs from the responder device 120, at 360, the initiator device 110 descrambles the scrambled LTF sequences in the multiple NDPs based on the derived key shared between the initiator device 110 and the responder device 120, the first SAC, and the initial value of the LTF sequence counter to obtain multiple descrambled LTF sequences.

[0103] At 370, the initiator device 110 determines the CSI of the channel between the responder device 120 and the initiator device 110 based on the multiple descrambled LTF sequences. Since the original LTF sequence (i.e., the LTF sequence before scrambling) is known to both the initiator device 110 and the responder device 120, the initiator device 110 can determine the CSI based on the descrambled LTF sequence and the original LTF sequence. For example, the initiator device 110 can determine the CSI based on the following equation (3):

[0104]

[0105] in Indicates CSI, R RLTF represents the descrambled LTF sequence, L LTF Represents the original LTF sequence.

[0106] After determining the CSI, at 380, the initiator device 110 performs security sensing based on the determined CSI. It is understood that the initiator device 110 can perform security sensing based on the determined CSI using any known or future developed algorithm. The scope of the present disclosure is not limited in this respect.

[0107] The impact of the movement of the detection target 130 on the CSI has a certain correlation in time, and the phase change of the CSI caused by the movement of the detection target 130 is continuous. Using the scheme of the present disclosure, the initiator device 110 can receive multiple NDPs from the responder device 120, and multiple descrambled LTF sequences can be obtained by descrambling the scrambled LTF sequences in the multiple NDPs. Furthermore, the initiator device 110 can obtain the CSI data of the channel within a period of time based on the multiple descrambled LTF sequences. Using the acquired CSI data within a period of time, the initiator device 110 can sense whether the detection target 130 is moving and what specific actions it is taking.

[0108] In addition, since the illegal initiator device cannot know the derived key shared between the initiator device 110 and the responder device 120, it cannot know the scrambling method of the LTF sequence in the NDP. Therefore, although the attacker device can receive the NDP from the responder device, it cannot descramble the LTF sequence therein, and thus cannot obtain the CSI data of the channel, and further cannot use the CSI data to perceive the action or behavior of the detection target 130. As a result, the behavior privacy of the detection target 130 is securely protected.

[0109] In addition, it can be understood that the solution of the present disclosure performs random modification on the LTF sequence by scrambling the LTF sequence, but does not modify the wireless data transmitted between the initiator device 110 and the responder device 120. Therefore, the solution of the present disclosure achieves security and privacy protection for wireless-aware users while coexisting with the existing wireless data transmission function.

[0110] In some embodiments, the initiator device 110 may use NDP for CSI feedback. Compared with the prior art in which CSI feedback is performed in a data manner, the embodiments of the present disclosure reduce the occupancy of the channel by CSI feedback. For example, in the prior art, CSI measurement can be performed on 114 subcarriers. In the case where the initiator device 110 uses 4 transmitting antennas and the responder device 120 uses 4 receiving antennas, the CSI associated with each subcarrier is a 4*4 matrix, each matrix element is a complex number, and the real part and the imaginary part are represented by 8-bit integers respectively. In this way, the CSI matrix associated with 114 subcarriers needs to occupy 3648 bytes. Even if the compression algorithm in the IEEE 802.11ac protocol is used, thousands of bytes are required in the prior art to represent a measurement result of CSI. The embodiments of the present disclosure use NDP for reverse measurement, and the NDP only contains the LTF header but not the data, which greatly reduces the occupancy of the channel. In addition, the short NDP also allows multiple initiator devices to provide CSI feedback simultaneously in a frequency division manner or a space division manner, which further reduces the CSI measurement cost.

[0111] Hereinafter, how to scramble multiple LTF sequences to obtain multiple scrambled LTF sequences (ie, randomized LTF sequences) will be described in detail in conjunction with specific embodiments.

[0112] The impact of the action of the detection target on the channel has a certain correlation. Therefore, the randomized LTF sequences in multiple NDPs should also have the same correlation in timing. Otherwise, the attacking device can use channel characteristics to distinguish the impact of the randomized LTF sequence on the channel and the impact of the action of the detection target on the channel. The embodiment of the present invention uses a linear predictive coding method to ensure that the randomized LTF sequence and the impact of the action of the detection target on the channel have the same correlation, thereby achieving the purpose of security perception.

[0113] In order to obtain multiple scrambled LTF sequences that can achieve security perception purposes, in some embodiments, the responder device 120 can determine the index of the scrambling sequence and the linear prediction coefficient set based on the derived key shared between the initiator device 110 and the responder device 120, and the initial value of the LTF sequence counter. As an example, the responder device 120 can determine the index of the scrambling sequence and the linear prediction coefficient set based on the hash function shown in the above formula (1). It should be understood that the above formula (1) is only an example for determining the index of the scrambling sequence and the linear prediction coefficient set. The responder device 120 can determine these two parameters based on the initial value of the LTF counter and the derived key using any appropriate method.

[0114] After determining the scrambling sequence, the responder device 120 can use the scrambling sequence to scramble the first LTF sequence in the multiple LTF sequences to obtain the first scrambled LTF sequence. Here, the first scrambled LTF sequence refers to the scrambled LTF sequence to be sent in the starting NDP (i.e., the first NDP). In some embodiments, the responder device 120 can use the same method as the scrambling sequence Secure-LTF-bits-R2I in the Secure Fine Timing Measurement positioning protocol in the IEEE 802.11az protocol to generate a randomized LTF sequence to scramble the first LTF sequence to obtain the first scrambled LTF sequence. For example, the responder device 120 can obtain the first scrambled LTF sequence by multiplying the first LTF sequence with the scrambling sequence Secure-LTF-bits-R2I.

[0115] In addition, the responder device 120 may be pre-configured with a plurality of linear prediction coefficient sets. After determining the index of the linear prediction coefficient set, the responder device 120 may determine the linear prediction coefficient set associated with the index from the pre-configured plurality of linear prediction coefficient sets. Furthermore, the responder device 120 may scramble the subsequent LTF sequences in the plurality of LTF sequences using the determined linear prediction coefficient set and the first scrambled LTF sequence to obtain subsequent scrambled LTF sequences. Here, the subsequent scrambled LTF sequence refers to the scrambled LTF sequence to be sent in the NDP after the start NDP.

[0116] Similarly, the initiator device 110 can determine the index of the descrambling sequence and the set of linear prediction coefficients based on the derived key shared between the initiator device 110 and the responder device 120, and the initial value of the LTF sequence counter. As an example, the initiator device 110 can determine the index of the descrambling sequence and the set of linear prediction coefficients based on the hash algorithm shown in the above formula (1). It should be understood that the above formula (1) is only an example for determining the index of the descrambling sequence and the set of linear prediction coefficients. The initiator device 110 can determine these two parameters based on the initial value of the LTF counter and the derived key using any appropriate algorithm.

[0117] After determining the descrambling sequence, the initiator device 110 can use the descrambling sequence to descramble the first scrambled LTF sequence among the multiple scrambled LTF sequences to obtain the first descrambled LTF sequence. Here, the first descrambled LTF sequence refers to the LTF sequence obtained by descrambling the scrambled LTF sequence in the starting NDP (i.e., the first NDP). In some embodiments, the initiator device 110 can use the same method as the descrambling sequence Secure-LTF-bits-I2R used in the Secure Fine Timing Measurement positioning protocol in the IEEE 802.11az protocol to generate a derandomized LTF sequence to descramble the first scrambled LTF sequence to obtain the first descrambled LTF sequence.

[0118] In addition, the initiator device 110 may be pre-configured with multiple linear prediction coefficient sets that are the same as those of the responder device 120. After determining the index of the linear prediction coefficient set, the initiator device 110 may determine the linear prediction coefficient set associated with the index from the pre-configured multiple linear prediction coefficient sets. Furthermore, the initiator device 110 may use the determined linear prediction coefficient set and the first descrambled LTF sequence to descramble subsequent scrambled LTF sequences in the multiple scrambled LTF sequences to obtain subsequent descrambled LTF sequences. Here, the subsequent descrambled LTF sequence refers to an LTF sequence obtained by descrambling the scrambled LTF sequence in the NDP after the starting NDP.

[0119] Hereinafter, an algorithm for determining a plurality of pre-configured linear prediction coefficient sets will be described in conjunction with specific examples. Each linear prediction coefficient set may include any appropriate number of elements. In the following examples, each linear prediction coefficient set will be described as including 9 elements. However, it should be understood that this is merely an example, and the scope of the present disclosure is not limited in this respect. The number of elements in the linear prediction coefficient set is also referred to as the order of the linear prediction coefficient. In other words, in this example, the order of the linear prediction coefficient is 9.

[0120] Algorithm Overview

[0121] Algorithm input: CSI data associated with a certain action over a period of time. Examples of actions may include but are not limited to: walking, running, falling, punching, etc. The CSI data associated with a certain action is obtained by using an existing network card that supports CSI extraction as a receiver to obtain the detection target in the test environment (e.g. Figure 1 The CSI data associated with the action can be represented in the time domain as {xm |m=0,1,2…,N-1}.

[0122] Algorithm output: 9th order linear prediction coefficient, which can be expressed as {a i |i=1,2,3…,9}.

[0123] Algorithm Description

[0124]

[0125] Where x(n) represents the n+1th scrambled LTF sequence, represents the estimated value of x(n), a i represents the i-th linear prediction coefficient in the linear prediction coefficient set, p represents the number of elements in the linear prediction coefficient set (i.e., the order of the linear prediction coefficient), 7≤p≤15 (in this example, p=9), 1≤i≤p, 1≤n≤N-1, and N represents the total number of NDPs for security awareness sent by the responding device to the initiating device. It can be seen from the above formula (4) that for The previous p scrambled LTF sequences {x i |i=np,n-p+1,…,n-1}.

[0126] x(n) and its estimated value The difference is called the linear prediction error and is represented by e(n) as follows:

[0127]

[0128] The basic problem of linear prediction is to determine a set of linear prediction coefficients {a i |i=1,2,3…,9} (i.e., a set of linear prediction coefficients) so that the error is minimized under a certain criterion. The criterion may be, for example, the "least mean square" (LMS) criterion. The predicted quadratic error E is:

[0129]

[0130] In order to minimize E, each linear prediction coefficient a j Should satisfy E for a j The partial derivative of is equal to 0, that is:

[0131] (1≤j≤p) (7)

[0132]

[0133] This gives the following linear equations:

[0134]

[0135] If you define:

[0136]

[0137] Then formula (9) can be rewritten as:

[0138] (1≤j≤p) (11)

[0139] The algorithm defines that x(n) is equal to 0 except 0≤n≤N-1, that is, x(i)=0, i∈(-∞,0)∪(N-1,+∞). The autocorrelation function r(j) of x(n) is defined as:

[0140]

[0141] Since we only care about the relevant results of the input data, the autocorrelation r(j) can be expressed as:

[0142]

[0143] Comparing formula (10) and formula (12), we can see that So formula (11) can be expressed as:

[0144]

[0145] The leftmost matrix in equation (14) is called the correlation matrix. The correlation matrix is ​​symmetric about the main diagonal, and all elements on the diagonal parallel to the main diagonal are equal. This matrix is ​​called a Toeplitz matrix. The coefficient matrix is ​​the linear equation of the Toeplitz matrix, which is called the Yule-Walker equation. The Yule-Walker equation does not require a lot of calculations like solving general equations. An efficient recursive solution can be obtained by using the properties of the Toeplitz matrix. Solving equation (11) can obtain a set of linear prediction coefficients {a i |i=1, 2, 3, . . . , p}, that is, a set of linear prediction coefficients.

[0146] Since a set of linear prediction coefficients is obtained by using CSI data associated with a certain action as an algorithm input, the set of linear prediction coefficients obtained in this way is also called a set of linear prediction coefficients associated with the action.

[0147] As mentioned above, the first scrambled LTF sequence x(0) is obtained by scrambling the first LTF sequence among multiple LTF sequences using the scrambling sequence. Therefore, in this paper, the first scrambled LTF sequence x(0) and its estimated value Can be used interchangeably.

[0148] After the linear prediction coefficients are determined, once the first scrambled LTF sequence x(0) (i.e., the first scrambled LTF sequence) is determined, the estimated value of the n+1th scrambled LTF sequence can be determined using the following equation (15):

[0149]

[0150] Among them, the definition It is equal to 0 outside 0≤n≤N-1, that is i∈(-∞, 0)∪(N-1, +∞). It can be seen from formula (15) that the estimated value of the n+1th scrambled LTF sequence is a linear combination of the estimated values ​​of the p scrambled LTF sequences before the estimated value of the n+1th scrambled LTF sequence. The coefficients of the linear combination are elements in the linear prediction coefficient set. For example, when p=9, the estimated value of the 10th scrambled LTF sequence is a linear combination of the estimated values ​​of the 1st scrambled LTF sequence to the estimated values ​​of the 9th scrambled LTF sequence, the estimated value of the 11th scrambled LTF sequence is a linear combination of the estimated values ​​of the 2nd scrambled LTF sequence to the estimated values ​​of the 10th scrambled LTF sequence, and so on.

[0151] It should be understood that in the above embodiment, the first scrambled LTF sequence is represented by n=0, and in other embodiments, the first scrambled LTF sequence is represented by n=1. In this case, the estimated value of the first scrambled LTF sequence is It can also be done by To indicate that, accordingly, The estimated value of the nth scrambled LTF sequence may be represented, and the scope of the present disclosure is not limited in this respect.

[0152] The above algorithm is used to obtain sets of linear prediction coefficients associated with walking, running, falling and boxing actions, as shown in Table 2 below.

[0153] Table 2

[0154]

[0155] It can be understood that the four linear prediction coefficient sets shown in Table 2 are merely examples, and more or fewer linear prediction coefficient sets may be determined depending on the number of actions associated with the algorithm input.

[0156] In addition, in some embodiments, the index of the linear prediction coefficient set may occupy any appropriate number of bits. For example, when the number of linear prediction coefficient sets is 4, its index may occupy 4 bits, such as 0000, 0001, 0010, 0011. Alternatively, when the number of linear prediction coefficient sets is 4, its index may occupy 2 bits, such as 00, 01, 10, 11. It will be understood that this is merely an example and is not intended to limit the scope of the present disclosure.

[0157] As described above, the responder device 120 may be pre-configured with a plurality of linear prediction coefficient sets. For example, the responder device 120 may be pre-configured with four linear prediction coefficient sets as shown in Table 2. Each linear prediction coefficient set may be associated with an index of a linear prediction coefficient set. For example, in the case where the index of the linear prediction coefficient set occupies 4 bits, the linear prediction coefficient set associated with walking shown in Table 2 may be associated with an index of 0000, the linear prediction coefficient set associated with running may be associated with an index of 0001, and so on.

[0158] After determining the index of the linear prediction coefficient set based on the above formula (1), the responder device 120 can determine the linear prediction coefficient set associated with the index from the pre-configured multiple linear prediction coefficient sets. For example, when the index of the linear prediction coefficient set is determined to be 0000, the linear prediction coefficient set associated with walking can be determined from the four linear prediction coefficient sets shown in Table 2. Furthermore, the responder device 120 can use the determined linear prediction coefficient set and the first scrambled LTF sequence to scramble the subsequent LTF sequences in the multiple LTF sequences to obtain the subsequent scrambled LTF sequences.

[0159] Similarly, the initiator device 110 may be pre-configured with the same plurality of linear prediction coefficient sets as the responder device 110. For example, the initiator device 110 may also be pre-configured with four linear prediction coefficient sets as shown in Table 2. Each linear prediction coefficient set may be associated with an index of a linear prediction coefficient set, which is the same as the index in the responder device 110. For example, in the case where the initiator device 110 is pre-configured with four linear prediction coefficient sets as shown in Table 2, the linear prediction coefficient set associated with walking is associated with index 0000, the linear prediction coefficient set associated with running is associated with index 0001, and so on.

[0160] In addition, after determining the index of the linear prediction coefficient set based on the above formula (1), the initiator device 110 can determine the linear prediction coefficient set associated with the index from the pre-configured multiple linear prediction coefficient sets. For example, when the index of the linear prediction coefficient set is determined to be 0000, the linear prediction coefficient set associated with walking can be determined from the four linear prediction coefficient sets shown in Table 2. Furthermore, the initiator device 110 can use the determined linear prediction coefficient set and the first descrambled LTF sequence to descramble subsequent scrambled LTF sequences in the multiple scrambled LTF sequences to obtain subsequent descrambled LTF sequences.

[0161] Although the attacker device can receive the NDP from the responder device 120, the attacker device cannot obtain the multiple linear prediction coefficient sets pre-configured by the initiator device 110 and the responder device 120, and thus cannot descramble the LTF sequence therein, thereby failing to obtain the CSI data of the channel, and further failing to use the CSI data to perceive the action or behavior of the detection target 130. As a result, the behavior privacy of the detection target is securely protected.

[0162] Example

[0163] Let's take walking as an example. Figure 5 The waveform diagram of CSI time domain data corresponding to walking action within a period of time obtained by using the prior art is shown. Figure 6 The time domain waveform diagram of the estimated values ​​of multiple LTF sequences determined according to the above equation (12) is shown.

[0164] Figure 7 Shows Figure 5 The spectrum of the CSI time domain data shown and Figure 6 The spectrum of the estimated value of the scrambled LTF sequence is shown. Figure 7 As shown, the spectrum 710 of the estimated value of the scrambled LTF sequence determined by the above algorithm is continuous, and thus can meet the coherence time requirement of the action of the detection target. In addition, the spectrum 710 of the estimated value of the scrambled LTF sequence determined by the above algorithm is very close to the spectrum 720 of the input CSI time domain data. In other words, the randomized LTF sequence and the impact of the action of the detection target on the channel have the same correlation. Therefore, the attacking device cannot remove the impact of the randomized LTF sequence by means of signal processing, obtain CSI data, and then identify the action of the detection target. In this way, the goal of security perception can be achieved.

[0165] Figure 8800 for security awareness according to some embodiments of the present disclosure. In some embodiments, the example method 800 may be implemented by the initiator device 110 in the example communication environment 100, for example, by a processor or processing unit of the initiator device 110 in conjunction with other components (e.g., a transceiver). In other embodiments, the example method 800 may also be implemented by other communication devices independent of the example communication system 100. For ease of description, reference will be made to Figure 1 An example method 800 is described.

[0166] At block 810, the initiator device 110 sends a security-aware request to the responder device 120. At block 820, the initiator device 110 receives a response to the security-aware request from the responder device 120, the response including the first sequence verification code and an initial value of the LTF counter.

[0167] At block 830, the initiator device 110 receives a plurality of NDPs for security awareness from the responder device 120. The plurality of NDPs each include a scrambled LTF sequence.

[0168] At box 840, the initiator device 110 descrambles the scrambled LTF sequences in the multiple NDPs based on the derived key shared between the initiator device 110 and the responder device 120, the first sequence verification code, and the initial value of the LTF counter to obtain multiple descrambled LTF sequences.

[0169] At block 850, the initiator device 110 determines channel state information between the responder device 120 and the initiator device 110 based on the plurality of descrambled LTF sequences. At block 860, the initiator device 110 performs security sensing based on the channel state information.

[0170] In some embodiments, descrambling the scrambled long training field sequences in a plurality of null data packets comprises: the initiator device 110 determines the index of the descrambling sequence and the set of linear prediction coefficients based on the derived key, the first sequence verification code, and the initial value of the long training field counter; descrambling the first scrambled long training field sequence in the plurality of null data packets using the descrambling sequence to obtain the first descrambled long training field sequence; and descrambling subsequent scrambled long training field sequences in the plurality of null data packets using the set of linear prediction coefficients and the first descrambled long training field sequence to obtain subsequent descrambled long training field sequences.

[0171] In some embodiments, descrambling subsequent scrambled long training field sequences in a plurality of null data packets to obtain subsequent descrambled long training field sequences comprises: obtaining an estimate of the (n+1)th descrambled long training field sequence based on:

[0172]

[0173] in represents the estimated value of the n+1th descrambled long training field sequence, a i represents the i-th linear prediction coefficient in the linear prediction coefficient set, p represents the number of elements in the linear prediction coefficient set, 7≤p≤15, 1≤i≤p, 1≤n≤N-1, and N represents the number of multiple empty data packets.

[0174] In some embodiments, the initiator device 110 sending a security awareness request to the responder device 120 includes: the initiator device 110 sending an initial fine timing measurement request frame to the responder device 120, wherein a trigger field in the initial fine timing measurement request frame is set to a predefined value indicating a security awareness request.

[0175] In some embodiments, method 800 further includes: before receiving each empty data packet in a plurality of empty data packets, the initiator device 110 updates the initial value of the long training field counter in response to receiving a control frame associated with the corresponding empty data packet from the responder device 120 to obtain an updated counter value, the control frame including a second sequence verification code; based on the derived key and the updated counter value, generates an updated first sequence verification code; and if the updated first sequence verification code is different from the second sequence verification code, the initiator device 110 resends the security awareness request to the responder device 120.

[0176] Fig. 9 1 shows a flowchart of an example method 900 for security awareness according to other embodiments of the present disclosure. In some embodiments, the example method 900 may be implemented by the responder device 120 in the example communication environment 100, for example, by a processor or processing unit of the responder device 120 in conjunction with other components (e.g., a transceiver). In other embodiments, the example method 900 may also be implemented by other communication devices independent of the example communication system 100. For ease of description, reference will be made to Figure 1 An example method 900 is described.

[0177] At block 910, the responder device 120 receives a security awareness request from the initiator device. At block 920, the responder device 120 sends a response to the security awareness request to the initiator device. The response includes a first sequence verification code and an initial value of a long training field counter for descrambling a plurality of scrambled long training field sequences.

[0178] At block 930, the responder device 120 scrambles the plurality of long training field sequences based on the derived key shared between the initiator device and the responder device and the initial value of the long training field counter to obtain a plurality of scrambled long training field sequences. At block 940, the responder device 120 sends a plurality of null data packets for security awareness to the initiator device, each of the plurality of null data packets including one of the plurality of scrambled long training field sequences.

[0179] In some embodiments, scrambling a plurality of long training field sequences to obtain a plurality of scrambled long training field sequences includes: the responder device 120 determines an index of a scrambling sequence and a set of linear prediction coefficients based on a derived key and an initial value of a long training field counter; scrambling a first long training field sequence of the plurality of long training field sequences using the scrambling sequence to obtain a first scrambled long training field sequence; and scrambling subsequent long training field sequences of the plurality of long training field sequences using the set of linear prediction coefficients and the first scrambled long training field sequence to obtain subsequent scrambled long training field sequences.

[0180] In some embodiments, scrambling a subsequent long training field sequence in a plurality of long training field sequences to obtain a subsequent scrambled long training field sequence comprises:

[0181] An estimate of the n+1th scrambled long training field sequence is obtained based on:

[0182]

[0183] in represents the estimated value of the n+1th scrambled long training field sequence, a i represents the i-th linear prediction coefficient in the linear prediction coefficient set, p represents the number of elements in the linear prediction coefficient set, 7≤p≤15, 1≤i≤p, 1≤n≤N-1, and N represents the number of multiple empty data packets.

[0184] In some embodiments, the responder device 120 receiving a security-aware request from the initiator device 110 includes: the responder device 120 receiving an initial fine timing measurement request frame from the initiator device 110, wherein a trigger field in the initial fine timing measurement request frame is set to a predefined value indicating a security-aware request.

[0185] In some embodiments, method 900 further includes: before sending each empty data packet in multiple empty data packets, in response to sending a control frame associated with the corresponding empty data packet to the initiator device 110, the responder device 120 updates the initial value of the long training field counter to obtain an updated counter value; based on the derived key and the updated counter value, generates an updated first sequence verification code as a second sequence verification code; and the responder device 120 sends a control frame to the initiator device 110, the control frame including the second sequence verification code, which is used by the initiator device 110 to determine whether to resend the security awareness request to the responder device 120.

[0186] Fig.10 1 shows a schematic block diagram of an initiator device 1000 according to some embodiments of the present disclosure. The initiator device 1000 may be implemented in Figure 1 The initiator device 110 shown may be implemented as a chip or chip system in the initiator device 110, or may be implemented in Figure 2 Any of the initiator devices 110 - 1 through 110 - 6 is shown as being implemented as a chip or chip system in any of the initiator devices 110 - 1 through 110 - 6 , and the scope of the present disclosure is not limited in this regard.

[0187] like Fig.10 As shown, the initiator device 1000 includes a sending unit 1010, a receiving unit 1020, a descrambling unit 1030, a determining unit 1040 and a sensing unit 1050. The sending unit 1010 is configured to send a security sensing request to the responder device. The receiving unit 1020 is configured to receive a response to the security sensing request from the responder device, and the response includes a first sequence verification code and an initial value of a long training field counter. The receiving unit 1020 is also configured to receive a plurality of empty data packets for security sensing from the responder device. The plurality of empty data packets each include a scrambled long training field sequence. The descrambling unit 1030 is configured to descramble the scrambled long training field sequence in the plurality of empty data packets based on a derived key shared between the initiator device and the responder device, the first sequence verification code and the initial value of the long training field counter to obtain a plurality of descrambled long training field sequences. The determining unit 1040 is configured to determine the channel state information between the responder device and the initiator device based on the plurality of descrambled long training field sequences. The sensing unit 1050 is configured to perform security sensing based on the channel state information.

[0188] In some embodiments, the descrambling unit 1030 is further configured to: determine the index of the descrambling sequence and the linear prediction coefficient set based on the derived key, the first sequence verification code and the initial value of the long training field counter; use the descrambling sequence to descramble the first scrambled long training field sequence in multiple empty data packets to obtain the first descrambled long training field sequence; and use the linear prediction coefficient set and the first descrambled long training field sequence to descramble subsequent scrambled long training field sequences in multiple empty data packets to obtain subsequent descrambled long training field sequences.

[0189] In some embodiments, the descrambling unit 1030 is further configured to obtain an estimate of the n+1th descrambled long training field sequence based on:

[0190]

[0191] in represents the estimated value of the n+1th descrambled long training field sequence, a i represents the i-th linear prediction coefficient in the linear prediction coefficient set, p represents the number of elements in the linear prediction coefficient set, 7≤p≤15, 1≤i≤p, 1≤n≤N-1, and N represents the number of multiple empty data packets.

[0192] In some embodiments, the sending unit 1010 is further configured to: send an initial fine timing measurement request frame to the responder device, wherein the trigger field in the initial fine timing measurement request frame is set to a predefined value, and the predefined value indicates a security awareness request.

[0193] In some embodiments, the receiving unit 1020 is further configured to: receive a control frame associated with the corresponding empty data packet from the responder device before receiving each empty data packet in the plurality of empty data packets. In such an embodiment, the device 1000 further includes an updating unit configured to: update the initial value of the long training field counter in response to receiving the control frame associated with the corresponding empty data packet from the responder device to obtain an updated counter value, the control frame including the second sequence verification code; and generate an updated first sequence verification code based on the derived key and the updated counter value. In such an embodiment, the sending unit 1010 is further configured to: resend the security awareness request to the responder device if the updated first sequence verification code is different from the second sequence verification code.

[0194] Fig.11 FIG. 1 is a schematic block diagram of a responder device 1100 according to some embodiments of the present disclosure. The responder device 1100 may be implemented in Figure 1 or Figure 2The responder device 120 is shown, or may be implemented as a chip or a chip system in the responder device 120, and the scope of the present disclosure is not limited in this regard.

[0195] like Fig.11 As shown, the responder device 1100 includes a receiving unit 1110, a sending unit 1120 and a scrambling unit 1130. The receiving unit 1110 is configured to receive a security perception request from an initiator device. The sending unit 1120 is configured to send a response to the security perception request to the initiator device, the response including a first sequence verification code and an initial value of a long training field counter, for descrambling a plurality of scrambled long training field sequences. The scrambling unit 1130 is configured to scramble a plurality of long training field sequences based on a derived key shared between the initiator device and the responder device and an initial value of a long training field counter by the responder device to obtain a plurality of scrambled long training field sequences. The sending unit 1120 is further configured to send a plurality of empty data packets for security perception to the initiator device. The plurality of empty data packets each include one of a plurality of scrambled long training field sequences.

[0196] In some embodiments, the scrambling unit 1130 is further configured to: determine the index of the scrambling sequence and the set of linear prediction coefficients based on the derived key and the initial value of the long training field counter; scramble the first long training field sequence in the multiple long training field sequences using the scrambling sequence to obtain a first scrambled long training field sequence; and scramble subsequent long training field sequences in the multiple long training field sequences using the set of linear prediction coefficients and the first scrambled long training field sequence to obtain subsequent scrambled long training field sequences.

[0197] In some embodiments, the scrambling unit 1130 is further configured to obtain an estimate of the n+1th scrambled long training field sequence based on:

[0198]

[0199] in represents the estimated value of the n+1th scrambled long training field sequence, a i represents the i-th linear prediction coefficient in the linear prediction coefficient set, p represents the number of elements in the linear prediction coefficient set, 7≤p≤15, 1≤i≤p, 1≤n≤N-1, and N represents the number of multiple empty data packets.

[0200] It should be understood that in the above-mentioned device embodiments, the first scrambled LTF sequence is represented by n=0, and in other embodiments, the first scrambled LTF sequence is represented by n=1. In this case, the estimated value of the first scrambled LTF sequence is It can also be done by To indicate that, accordingly, The estimated value of the nth scrambled LTF sequence may be represented, and the scope of the present disclosure is not limited in this respect.

[0201] In some embodiments, the receiving unit 1110 is further configured to receive an initial fine timing measurement request frame from an initiator device, wherein a trigger field in the initial fine timing measurement request frame is set to a predefined value, and the predefined value indicates a security awareness request.

[0202] In some embodiments, the device 1100 further includes an updating unit. The updating unit is configured to: before sending each of the plurality of empty data packets, in response to sending a control frame associated with the corresponding empty data packet to the initiator device, update the initial value of the long training field counter to obtain an updated counter value; based on the derived key and the updated counter value, generate an updated first sequence verification code as the second sequence verification code. In such an embodiment, the receiving unit 1100 is further configured to send a control frame to the initiator device, the control frame including the second sequence verification code, for the initiator device to determine whether to resend the security awareness request to the responder device.

[0203] Fig.12 A simplified block diagram of an example apparatus 1200 according to some embodiments of the present disclosure is shown. The apparatus 1200 may be used to implement the initiator device 1000 or the responder device 1100 in the above embodiments. As shown in the figure, the apparatus 1200 includes one or more processors 1210, one or more memories 1220 coupled to the processor 1210, and a communication module 1240 coupled to the processor 1210.

[0204] The communication module 1240 may be used for two-way communication. The communication module 1240 may have at least one communication interface for communication. The communication interface may include any interface necessary for communication with other devices.

[0205] Processor 1210 may be of any type suitable for the local technology network, and may include, but is not limited to, at least one of the following: a general purpose computer, a special purpose computer, a microcontroller, a digital signal processor (DSP), or one or more of a controller-based multi-core controller architecture. Device 1200 may have multiple processors, such as application specific integrated circuit chips, which are time-dependent from a clock synchronized with a main processor.

[0206] The memory 1220 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, at least one of the following: read-only memory (ROM) 1224, erasable programmable read-only memory (EPROM), flash memory, hard disk, compact disc (CD), digital video disc (DVD), or other magnetic storage and / or optical storage. Examples of volatile memories include, but are not limited to, at least one of the following: random access memory (RAM) 1222, or other volatile memories that do not persist during the duration of a power outage.

[0207] Computer program 1230 includes computer executable instructions executed by associated processor 1210. Program 1230 may be stored in ROM 1224. Processor 1210 may perform any suitable actions and processes by loading program 1230 into RAM 1222.

[0208] The embodiment of the present disclosure can be implemented with the help of program 1230, so that the device 1200 can execute the Figures 3 to 9 Any process discussed. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0209] In some embodiments, the program 1230 may be tangibly embodied in a computer-readable medium that may be included in the apparatus 1200 (such as in the memory 1220) or other storage device accessible by the apparatus 1200. The program 1230 may be loaded from the computer-readable medium to the RAM 1222 for execution. The computer-readable medium may include any type of tangible non-volatile memory, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc.

[0210] In some embodiments, the communication module 1240 in the device 1200 may be implemented as a transmitter and a receiver (or a transceiver), which may be configured to send / receive system information, such as a management frame, an acknowledgement frame, etc. In addition, the device 1200 may further include one or more of a scheduler, a controller, and a radio frequency / antenna, which will not be elaborated in detail in this disclosure.

[0211] In another implementation, the RF / antenna may be arranged independently of the processor performing baseband processing. For example, in a distributed scenario, the RF / antenna may be arranged independently of the device 1200 in a remote manner.

[0212] Exemplarily, the apparatus 1200 may be implemented as an initiator device or a responder device, or may be implemented as a chip or a chip system in an initiator device, or may be implemented as a chip or a chip system in a responder device, which is not limited in the embodiments of the present disclosure.

[0213] In general, various embodiments of the present disclosure may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software, which may be performed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of the present disclosure are shown and described as block diagrams, flow charts, or using some other graphical representation, it should be understood that the blocks, devices, systems, techniques, or methods described herein may be implemented as, by way of non-limiting example, hardware, software, firmware, dedicated circuits or logic, general purpose hardware or controllers or other computing devices, or some combination thereof.

[0214] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer executable instructions, such as instructions included in a program module, which are executed in a device on a real or virtual processor of a target to perform the above-referenced Figures 3 to 9 Typically, a program module includes routines, programs, libraries, objects, classes, components, data structures, etc. that perform specific tasks or implement specific abstract data types. In various embodiments, the functions of program modules can be combined or divided between program modules as needed. Machine executable instructions for program modules can be executed in local or distributed devices. In distributed devices, program modules can be located in local and remote storage media.

[0215] The computer program code for realizing the method of the present disclosure can be written in one or more programming languages. These computer program codes can be provided to the processor of general-purpose computer, special-purpose computer or other programmable data processing device, so that the program code, when being executed by computer or other programmable data processing device, causes the function / operation specified in flow chart and / or block diagram to be implemented. The program code can be executed completely on computer, partly on computer, as independent software package, partly on computer and partly on remote computer or completely on remote computer or server.

[0216] In the context of the present disclosure, computer program codes or related data may be carried by any appropriate carrier to enable a device, apparatus or processor to perform the various processes and operations described above. Examples of carriers include signals, computer readable media, and the like. Examples of signals may include electrical, optical, radio, acoustic or other forms of propagation signals, such as carrier waves, infrared signals, and the like.

[0217] A computer readable medium may be any tangible medium that contains or stores a program for or related to an instruction execution system, apparatus, or device. A computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination thereof. More detailed examples of computer readable storage media include an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0218] In addition, although the operation of the method of the present disclosure is described in a particular order in the accompanying drawings, this does not require or imply that these operations must be performed in this particular order, or that all the operations shown must be performed to achieve the desired result. On the contrary, the steps depicted in the flow chart can change the order of execution. Additionally or alternatively, some steps can be omitted, multiple steps can be combined into one step for execution, and / or one step can be decomposed into multiple steps for execution. It should also be noted that the features and functions of two or more devices according to the present disclosure can be embodied in one device. Conversely, the features and functions of a device described above can be further divided into being embodied by multiple devices.

[0219] The above descriptions of various implementations of the present disclosure are exemplary, non-exhaustive, and not limited to the disclosed implementations. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described implementations. The selection of terms used herein is intended to explain the principles of the implementations, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the various implementations disclosed herein.

Claims

1. A security perception method, comprising: The initiator device sends a security awareness request to the responder device; The initiator device receives a response to the security awareness request from the responder device, the response including a first sequence verification code and an initial value of a long training field counter; The initiator device receives a plurality of null data packets for the security awareness from the responder device, each of the plurality of null data packets comprising a scrambled long training field sequence; The initiator device descrambles the scrambled long training field sequences in the plurality of null data packets based on the derived key shared between the initiator device and the responder device, the first sequence verification code, and the initial value of the long training field counter to obtain a plurality of descrambled long training field sequences; The initiator device determines, based on the plurality of descrambled long training field sequences, channel state information of a channel between the responder device and the initiator device; as well as The initiator device performs the security perception based on the channel state information.

2. The method of claim 1 , wherein descrambling the scrambled long training field sequences in the plurality of null data packets comprises: The initiator device determines, based on the derived key, the first sequence verification code, and the initial value of the long training field counter, an index of a descrambling sequence and a linear prediction coefficient set; Descrambling a first scrambled long training field sequence in the plurality of null data packets using the descrambling sequence to obtain a first descrambled long training field sequence; as well as The subsequent scrambled long training field sequences in the plurality of null data packets are descrambled using the linear prediction coefficient set and the first descrambled long training field sequence to obtain subsequent descrambled long training field sequences.

3. The method according to claim 2, wherein descrambling subsequent scrambled long training field sequences in the plurality of null data packets to obtain subsequent descrambled long training field sequences comprises: An estimate of the n+1th descrambled long training field sequence is obtained based on: in represents the estimated value of the n+1th descrambled long training field sequence, a i represents the i-th linear prediction coefficient in the linear prediction coefficient set, p represents the number of elements in the linear prediction coefficient set, 7≤p≤15, 1≤i≤p, 1≤n≤N-1, and N represents the number of the multiple empty data packets.

4. The method according to claim 1, wherein the initiator device sending a security awareness request to the responder device comprises: The initiator device sends an initial fine timing measurement request frame to the responder device, wherein a trigger field in the initial fine timing measurement request frame is set to a predefined value, and the predefined value indicates the security awareness request.

5. The method according to claim 1, further comprising: The initiator device updates the initial value of the long training field counter in response to receiving a control frame associated with the corresponding null data packet from the responder device before receiving each null data packet in the plurality of null data packets to obtain an updated counter value, the control frame including a second sequence verification code; generating an updated first sequence verification code based on the derived key and the updated counter value; as well as If the updated first sequence verification code is different from the second sequence verification code, the initiator device resends the security awareness request to the responder device.

6. A security perception method, comprising: The responder device receives a security awareness request from the initiator device; The responder device sends a response to the security awareness request to the initiator device, wherein the response includes a first sequence verification code and an initial value of a long training field counter, which is used to descramble a plurality of scrambled long training field sequences; The responder device scrambles a plurality of long training field sequences based on a derived key shared between the initiator device and the responder device and the initial value of a long training field counter to obtain the plurality of scrambled long training field sequences; as well as The responder device sends a plurality of null data packets for the security awareness to the initiator device, each of the plurality of null data packets including one of the plurality of scrambled long training field sequences.

7. The method according to claim 6, wherein scrambling a plurality of long training field sequences to obtain the plurality of scrambled long training field sequences comprises: The responder device determines, based on the derived key and the initial value of the long training field counter, an index of a scrambling sequence and a set of linear prediction coefficients; scramble a first long training field sequence among the plurality of long training field sequences using the scrambling sequence to obtain a first scrambled long training field sequence; as well as The subsequent long training field sequences in the plurality of long training field sequences are scrambled using the linear prediction coefficient set and the first scrambled long training field sequence to obtain subsequent scrambled long training field sequences.

8. The method according to claim 7, wherein scrambling a subsequent long training field sequence in the plurality of long training field sequences to obtain a subsequent scrambled long training field sequence comprises: An estimate of the n+1th scrambled long training field sequence is obtained based on: in represents the estimated value of the n+1th scrambled long training field sequence, a i represents the i-th linear prediction coefficient in the linear prediction coefficient set, p represents the number of elements in the linear prediction coefficient set, 7≤p≤15, 1≤i≤p, 1≤n≤N-1, and N represents the number of the multiple empty data packets.

9. The method of claim 6, wherein the responder device receiving the security awareness request from the initiator device comprises: The responder device receives an initial fine timing measurement request frame from the initiator device, a trigger field in the initial fine timing measurement request frame being set to a predefined value, the predefined value indicating the security-aware request.

10. The method according to claim 6, further comprising: The responder device, before sending each of the plurality of null data packets, in response to sending a control frame associated with the corresponding null data packet to the initiator device, updates the initial value of the long training field counter to obtain an updated counter value; Based on the derived key and the updated counter value, generate an updated first sequence verification code as a second sequence verification code; as well as The responder device sends the control frame to the initiator device, where the control frame includes a second sequence verification code, which is used by the initiator device to determine whether to resend the security awareness request to the responder device.

11. An initiator device, comprising: A sending unit, configured to send a security awareness request to a responder device; The receiving unit is configured as follows: receiving a response to the security awareness request from the responder device, the response comprising a first sequence verification code and an initial value of a long training field counter; receiving a plurality of null data packets for the security awareness from the responder device, the plurality of null data packets each comprising a scrambled long training field sequence; a descrambling unit configured to descramble the scrambled long training field sequences in the plurality of null data packets based on a derived key shared between the initiator device and the responder device, the first sequence verification code, and the initial value of the long training field counter to obtain a plurality of descrambled long training field sequences; a determining unit configured to determine channel state information of a channel between the responder device and the initiator device based on the plurality of descrambled long training field sequences; as well as A sensing unit is configured to perform the security sensing based on the channel state information.

12. The apparatus according to claim 11, wherein the descrambling unit is further configured to: Determine an index of a descrambling sequence and a set of linear prediction coefficients based on the derived key, the first sequence verification code, and the initial value of a long training field counter; Descrambling a first scrambled long training field sequence in the plurality of null data packets using the descrambling sequence to obtain a first descrambled long training field sequence; as well as The subsequent scrambled long training field sequences in the plurality of null data packets are descrambled using the linear prediction coefficient set and the first descrambled long training field sequence to obtain subsequent descrambled long training field sequences.

13. The apparatus according to claim 12, wherein the descrambling unit is further configured to: An estimate of the n+1th descrambled long training field sequence is obtained based on: in represents the estimated value of the n+1th descrambled long training field sequence, a i represents the i-th linear prediction coefficient in the linear prediction coefficient set, p represents the number of elements in the linear prediction coefficient set, 7≤p≤15, 1≤i≤p, 1≤n≤N-1, and N represents the number of the multiple empty data packets.

14. The device according to claim 11, wherein the sending unit is further configured to: An initial fine timing measurement request frame is sent to the responder device, wherein a trigger field in the initial fine timing measurement request frame is set to a predefined value, wherein the predefined value indicates the security awareness request.

15. The device according to claim 11, wherein the receiving unit is further configured to: Prior to receiving each of the plurality of null data packets, receiving from the responder device a control frame associated with the corresponding null data packet; and The device further comprises an updating unit configured to: updating the initial value of the long training field counter in response to receiving a control frame associated with the corresponding null data packet from the responder device to obtain an updated counter value, the control frame including a second sequence verification code; generating an updated first sequence verification code based on the derived key and the updated counter value; and The sending unit is further configured to: if the updated first sequence verification code is different from the second sequence verification code, resend the security awareness request to the responder device.

16. A responder device, comprising: A receiving unit, configured to receive a security awareness request from an initiator device; a sending unit, configured to send a response to the security awareness request to the initiator device, wherein the response includes a first sequence verification code and an initial value of a long training field counter, which is used to descramble a plurality of scrambled long training field sequences; as well as a scrambling unit configured to scramble, by the responder device, a plurality of long training field sequences based on a derived key shared between the initiator device and the responder device and the initial value of a long training field counter to obtain the plurality of scrambled long training field sequences; The sending unit is further configured to send a plurality of null data packets for the security awareness to the initiator device, wherein each of the plurality of null data packets includes one of the plurality of scrambled long training field sequences.

17. The apparatus according to claim 16, wherein the scrambling unit is further configured to: Determining an index of a scrambling sequence and a set of linear prediction coefficients based on the derived key and the initial value of the long training field counter; scramble a first long training field sequence among the plurality of long training field sequences using the scrambling sequence to obtain a first scrambled long training field sequence; as well as The subsequent long training field sequences in the plurality of long training field sequences are scrambled using the linear prediction coefficient set and the first scrambled long training field sequence to obtain subsequent scrambled long training field sequences.

18. The apparatus according to claim 17, wherein the scrambling unit is further configured to: An estimate of the n+1th scrambled long training field sequence is obtained based on: in represents the estimated value of the n+1th scrambled long training field sequence, a i represents the i-th linear prediction coefficient in the linear prediction coefficient set, p represents the number of elements in the linear prediction coefficient set, 7≤p≤15, 1≤i≤p, 1≤n≤N-1, and N represents the number of the multiple empty data packets.

19. The device according to claim 16, wherein the receiving unit is further configured to: An initial fine timing measurement request frame is received from the initiator device, a trigger field in the initial fine timing measurement request frame being set to a predefined value, the predefined value indicating the security-aware request.

20. The apparatus of claim 16, further comprising: Update unit, configured as: Before sending each of the plurality of null data packets, in response to a control frame associated with the corresponding null data packet being sent to the initiator device, updating the initial value of the long training field counter to obtain an updated counter value; Based on the derived key and the updated counter value, generate an updated first sequence verification code as a second sequence verification code; and The receiving unit is further configured to send the control frame to the initiator device, wherein the control frame includes a second sequence verification code for the initiator device to determine whether to resend the security awareness request to the responder device.

21. A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the method according to any one of claims 1 to 5 or the method according to any one of claims 6 to 10.

22. A chip comprising a processing circuit and a communication interface, the processing circuit being configured to perform the method according to any one of claims 1 to 5 or the method according to any one of claims 6 to 10.

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