Sensitivity-based authentication-oriented key generation method and system

Abstract

The invention provides an authentication-oriented key generation method and system based on sensing. The method is applied to a communication perception integration (ISAC) system, and the system comprises an ISAC base station and a communication terminal. The method comprises the following steps: an ISAC base station obtains position information of a plurality of reference points in a surrounding environment and sends the position information of each reference point to a communication terminal; wherein the position information comprises an angle and a distance; the ISAC base station and the communication terminal fuse the angle and the distance of each reference point to obtain fusion position information of each reference point; the ISAC base station and the communication terminal divide the reference points into n groups based on the fusion position information of the reference points, and encode the number of the reference points in each group of reference points to obtain a first key; the ISAC base station and the communication terminal respectively carry out quantitative coding on channel characteristics between the ISAC base station and the communication terminal to obtain a second secret key; and the ISAC base station and the communication terminal respectively combine the first secret key and the second secret key to obtain a final secret key. According to the invention, the secrecy rate of the key can be improved.

Description

Technical Field

[0001] The present invention relates to the field of communication security technology, and in particular to a method and system for generating a key based on synaesthesia-oriented authentication. Background Art

[0002] The broadcast nature of wireless communications makes them vulnerable to eavesdropping and interference by attackers. Attackers may also interfere with wireless communications by sending malicious signals or tampering with transmitted data, resulting in communication interruptions and misleading information. Therefore, in the application of wireless communication technology, it is particularly important to ensure the security and confidentiality of communications. The basic idea of ​​physical layer key generation technology is to use the channel reciprocity between communication nodes as a common source of randomness in key generation. By extracting and comparing channel characteristics, the communicating parties can generate highly consistent and unpredictable keys, greatly enhancing communication security.

[0003] Current physical layer security technologies are based on the assumption of channel reciprocity. However, a major drawback of using channel reciprocity to generate keys is that the additive white Gaussian noise (AWGN) of the two receivers will affect the reciprocity of channel measurements. In addition, the two nodes must collect measurements at the same time. In addition, most of the deployed positioning technologies use received signal strength (RSS) to estimate distance. Estimating distance based on RSS requires accurate modeling of the channel between nodes, which results in large estimation errors. In addition, the key generated based on the distance between two communicating nodes can be easily obtained by an eavesdropper with the ability to estimate the angle of arrival (AOA), resulting in the current lack of key confidentiality. Summary of the invention

[0004] The embodiment of the present invention provides a key generation method and system based on synaesthesia-oriented authentication to solve the problem of improving the confidentiality of communication keys.

[0005] In a first aspect, an embodiment of the present invention provides a key generation method based on synaesthesia-oriented authentication, which is applied to an ISAC system, wherein the system includes an ISAC base station and a communication terminal; the method includes:

[0006] The ISAC base station obtains the location information of multiple reference points in the surrounding environment and sends the location information of each reference point to the communication terminal; wherein the location information includes angle and distance;

[0007] The ISAC base station and the communication terminal fuse the angle and distance of each reference point respectively to obtain the fused position information of each reference point;

[0008] The ISAC base station and the communication terminal divide each reference point into n groups based on the fused position information of each reference point, and encode the number of reference points in each group of reference points to obtain a first key; wherein n is a preset value;

[0009] The ISAC base station and the communication terminal respectively quantize and encode the channel characteristics between the ISAC base station and the communication terminal to obtain a second key;

[0010] The ISAC base station and the communication terminal respectively combine the first key and the second key to obtain a final key.

[0011] In a possible implementation, the ISAC base station and the communication terminal fuse the angle and distance of each reference point respectively to obtain fused position information of each reference point, including:

[0012] The ISAC base station and the communication terminal respectively use the ISAC base station as the origin and convert the polar coordinates of each reference point into Cartesian coordinates;

[0013] The ISAC base station and the communication terminal translate the Cartesian coordinates of each reference point based on the Cartesian coordinates of the first reference point to obtain the translated coordinates of each reference point; wherein the first reference point is a reference point specified by the ISAC base station among the reference points, and the translated coordinates of the first reference point are (0, 0);

[0014] The ISAC base station and the communication terminal respectively convert the translated coordinates of each reference point into polar coordinates as the fused position information of each reference point.

[0015] In a possible implementation, the ISAC base station and the communication terminal divide the reference points into n groups based on the fused position information of the reference points, and encode the number of reference points in each group of reference points to obtain a first key, including:

[0016] The ISAC base station and the communication terminal divide each reference point into n angle intervals according to the coordinate angle in the fused position information of each reference point; wherein the angle range of each angle interval is equal, and each reference point in each angle interval is a group;

[0017] The ISAC base station and the communication terminal respectively use binary numbers with a length of m / n to represent the number of reference points in each group of reference points, and combine them to obtain a first key with a length of m; wherein m is a preset value.

[0018] In a possible implementation, the ISAC base station and the communication terminal respectively combine the first key and the second key to obtain a final key, including:

[0019] The ISAC base station and the communication terminal respectively divide the second key into multiple segments of binary numbers with a length of q bits, and for each segment of binary numbers, use the binary digit that appears the most times in the segment of binary numbers to represent the segment of binary numbers, obtain m binary digits, and splice the m binary digits in the original order to obtain a compressed second key; wherein the second key is q times the length of the first key, m is the length of the first key, and q is a preset value;

[0020] The ISAC base station and the communication terminal perform XOR on the first key and the compressed second key respectively to obtain a final key.

[0021] In a possible implementation, the ISAC base station obtains location information of multiple reference points in the surrounding environment, including:

[0022] The ISAC base station allocates radar power and communication power based on the number of communication terminals, and scans the surrounding environment based on the radar power to obtain the location information of multiple reference points in the surrounding environment.

[0023] In a possible implementation, the ISAC base station obtains location information of multiple reference points in the surrounding environment and sends the location information of each reference point to the communication terminal, including:

[0024] If the number of reference points in the surrounding environment is greater than a preset threshold, a preset proportion of reference points are randomly removed, and the position information of the remaining reference points is sent to the communication terminal.

[0025] In a possible implementation manner, the ISAC base station sends the location information of each reference point to the communication terminal, including:

[0026] The ISAC base station performs channel estimation and equalization on the communication terminal to obtain equalizer coefficients, and uses the equalizer coefficients to send the position information of each reference point to the communication terminal.

[0027] In a second aspect, an embodiment of the present invention provides a key generation system based on synaesthesia-oriented authentication, including an ISAC base station and a communication terminal;

[0028] The ISAC base station is used to obtain the location information of multiple reference points in the surrounding environment and send the location information of each reference point to the communication terminal; wherein the location information includes angle and distance;

[0029] The ISAC base station and the communication terminal are used to fuse the angle and distance of each reference point respectively to obtain the fused position information of each reference point;

[0030] The ISAC base station and the communication terminal are respectively used to divide each reference point into n groups based on the fused position information of each reference point, and encode the number of reference points in each group of reference points to obtain a first key; wherein n is a preset value;

[0031] The ISAC base station and the communication terminal are used to quantize and encode the channel characteristics between the ISAC base station and the communication terminal respectively to obtain a second key;

[0032] The ISAC base station and the communication terminal are respectively used to combine the first key and the second key to obtain a final key.

[0033] The embodiment of the present invention provides a key generation method, device, terminal and storage medium based on synaesthesia-oriented authentication. The ISAC base station obtains information such as randomly distributed environmental nodes in the surrounding environment as reference points and extracts location information to send to the communication terminal. Both parties process the location information of the reference point in the same way and combine it with the channel characteristics to generate the final key. Compared with the prior art, it not only utilizes the randomness of the node information in the environment, but also integrates the various information of the nodes. Even if the eavesdropper obtains the same features, it is difficult to form a key that is exactly the same as the final key, thereby improving the confidentiality of the key. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0035] Figure 1 It is a flow chart of an implementation of a key generation method based on synaesthesia-oriented authentication provided by an embodiment of the present invention;

[0036] Figure 2 is a flow chart of an implementation of a key generation method based on synaesthesia-oriented authentication provided by another embodiment of the present invention;

[0037] Figure 3 It is a structural diagram of a key generation system based on synaesthesia-oriented authentication provided by an embodiment of the present invention;

[0038] Figure 4 It is a schematic diagram of the structure of a communication terminal provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0039] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0040] In order to make the purpose, technical solutions and advantages of the present invention more clear, specific embodiments will be described below in conjunction with the accompanying drawings.

[0041] The broadcast nature of wireless communications makes them vulnerable to eavesdropping and interference by attackers. Attackers may also interfere with wireless communications by sending malicious signals or tampering with transmitted data, resulting in communication disruptions and misleading information. Therefore, in the application of wireless communication technology, it is particularly important to ensure the security and confidentiality of communications. In addition, with the development of powerful computing devices, these encryption-based technologies are more vulnerable to attacks by sophisticated adversaries. In order to solve the problems faced by traditional security technologies, physical layer key generation technology has emerged, providing an effective complementary solution for asymmetric and symmetric encryption algorithms.

[0042] The basic idea of ​​this technology is to use the channel reciprocity between communication nodes as a common source of randomness in key generation. By extracting and comparing channel characteristics, the communicating parties can generate highly consistent and unpredictable keys, greatly enhancing communication security. Compared with traditional key generation methods, physical layer key generation technology has higher flexibility and security, and does not require additional key distribution and management mechanisms, thereby reducing system complexity and cost. At the same time, since key generation is based on channel characteristics rather than traditional encryption algorithms, it is more difficult to crack or steal.

[0043] Current physical layer security techniques are based on the channel reciprocity assumption. The most common feature of the channel characteristics is the channel amplitude, mainly because it is easy to implement. Current related techniques include developing a level-crossing algorithm that is best suited for Rician and Rayleigh fading in some papers. Some papers use ultra-wideband channel impulse responses as a common source of randomness. In some papers, the authors developed a technique to convert correlated channel measurements into uncorrelated binary data. In addition, some papers also use distance information to generate key bits.

[0044] In recent years, the key generation performance has been effectively improved by introducing RIS into the system. In some literatures, RIS was first introduced to assist in key generation in single-input single-output (SISO) networks, and in some literatures it was further extended to multi-antenna networks. Other literatures proposed a physical layer key generation scheme based on deep learning technology. The scheme first constructs a feature extraction network consisting of two autoencoders to extract the common features of the channel estimated by the legitimate nodes, and then develops a quantization algorithm with adaptive guard bands to generate a binary key sequence from the derived common features.

[0045] Some literatures propose a key generation algorithm based on vector quantization to improve the key generation rate at the expense of key randomness. In some literatures, a two-layer secure key generation scheme is used to utilize channel phase information to enhance the key generation rate performance. In order to improve the randomness performance of key generation, a multi-level non-uniform quantization strategy for generalized gamma (GG) fading channels is proposed in some literatures. The randomness performance is improved, but the key generation rate is not much different from other schemes. For Rayleigh, Rice, and Nakagami fading channels, some literatures propose a 2-level key generation scheme that derives an analytical expression for the average continuous duration (ACD) (i.e., average offset length) of the channel envelope within a given quantization region. This improves the randomness of the key generation rate. In order to help multiple Internet of Things (IoT) devices share a similar key, some literatures propose a group key generation strategy. In some literatures, the key generation scheme for the intra-band full-duplex (IBFD) MIMO system is studied.

[0046] In addition, compared with the usual wireless channel characteristics, the position of the reference node in the surrounding environment changes relatively slowly. The changing but relatively stable characteristics are suitable as key generation features, and the physical layer characteristics are unique and not easily obtained by attackers. The recently emerging integrated sensing and communication (ISAC) can utilize wireless infrastructure and scarce spectrum resources for communication and sensing, improving system performance at a lower cost. The ISAC network can obtain rich information about the surrounding environment through radar detection functions, and the low-dimensional physical resource space that can be used for key generation will be greatly expanded. The terminal nodes around the communication terminal are intended to be potential reference nodes, and the relative position information is used as reference key generation for environmental characteristics. Therefore, ISAC can be used to assist in the generation of physical layer keys.

[0047] A major disadvantage of using channel reciprocity to generate keys is that the additive white Gaussian noise (AWGN) of the two receivers will affect the reciprocity of channel measurements. In addition, the two nodes must collect measurements at the same time. Most of the currently deployed positioning technologies use received signal strength (RSS) to estimate the distance. Estimating the distance based on RSS requires accurate modeling of the channel between nodes, and the estimation error is large. In addition, the authors of some literatures did not consider that the key generated based on the distance between two communication nodes can be easily obtained by an eavesdropper with the ability to estimate the angle of arrival (AOA). Some literatures on RIS-assisted PLKG only study the key generation performance from the perspective of information theory, and use channel statistics to adjust the reflection coefficient matrix of RIS. In some literatures, deep learning is used to assist key generation. Although good performance can be achieved, the computational complexity is huge. Moreover, the above literatures do not consider key generation in the ISAC scenario, ignoring a large number of effective key generation features. Therefore, how to effectively utilize the interawareness function of the ISAC base station to achieve a key generation scheme with high information content, low key mismatch rate and low computational complexity is the main research goal of this patent.

[0048] The key generation scheme based on location and channel characteristics proposed in the present invention is as follows: Figure 1 As shown in the figure, it is mainly divided into five parts: base station radar positioning, reference node selection, positioning information processing, channel estimation and equalization, and key generation. In addition, the power allocation of the ISAC base station is analyzed at last.

[0049] First, the ISAC base station uses the radar detection function to locate the surrounding reference nodes, including distance and angle information. The Music algorithm is used for angle detection, and the matched filter algorithm is used for distance estimation. After the positioning is completed, the reference node needs to be selected according to the position and number of the reference node. Then, the selected reference node position information is sent to the communication terminal, and both parties perform channel estimation and equalization. The result of the channel estimation can be used as a channel feature to generate a key to enhance the generated key entropy. After equalization, the bit error rate of the communication terminal can be reduced, and the bit error probability of the reference node position information sent by the ISAC base station can be reduced, thereby reducing the BMR of the key generated by both parties. Next, both parties process the position of the reference node, transform the origin of the coordinates, make full use of the distance and angle information of the reference node, and finally generate a key.

[0050] See also Figure 2 , which shows a flowchart of the implementation of the key generation method based on synaesthesia-oriented authentication provided by an embodiment of the present invention, which is described in detail as follows:

[0051] The method is applied to an ISAC system, the system comprising an ISAC base station and a communication terminal; the method comprises:

[0052] Step 201: The ISAC base station obtains location information of multiple reference points in the surrounding environment, and sends the location information of each reference point to the communication terminal; wherein the location information includes angle and distance.

[0053] In this embodiment, the ISAC base station uses the radar detection function to locate the surrounding reference nodes, including distance and angle information. Specifically, the Music algorithm can be used for angle detection and the matched filter algorithm can be used for distance estimation. If the radar already has available location information of the surrounding reference nodes, the next step is directly executed.

[0054] Assuming that the ISAC base station has no available location information of surrounding reference nodes, the next step of radar detection is required.

[0055] (1) Pilot signal

[0056] Using an orthogonal linear frequency modulation (LFM) signal, which is a commonly used MIMO radar waveform, the pilot signal is defined as:

[0057]

[0058] Where P T is the total transmission power. P (N Bs ≤T P ) is the signal length.

[0059] Using HAD structure to transmit waveform S DP After that, Bs receives the signal reflected by the target, which can be expressed as

[0060]

[0061] in Where W RF is the simulation combination matrix with unit module,

[0062] is the equivalent received steering vector,

[0063] Next, the angle of the target is estimated first, followed by the Doppler parameter and the delay parameter.

[0064] (2) Angle estimation:

[0065] To estimate the angle, the classic MUSIC algorithm is used, which has a very high angular resolution.

[0066] make The received signal can be equivalent to

[0067] When N BS When it is big enough, The covariance matrix of

[0068]

[0069] in

[0070] According to the standard MUSIC algorithm, the eigenvalues ​​of the above formula are decomposed into Among them U S and U n Contains eigenvectors that span the signal subspace and the noise subspace, respectively.

[0071] The MUSIC spectrum can be expressed as By finding the K largest peaks, the AOAs of the K targets can be easily located.

[0072] (3) Delay and Doppler estimation:

[0073] The next step is to estimate the delay and Doppler parameters associated with each AOA, namely q k and p k The estimated AOA is expressed as θ k , firstly, the reference signal in each Doppler domain is vectorized as

[0074]

[0075] where d q and J p represent the qth Doppler interval and the pth range interval respectively.

[0076] if That is, the angle of the target is fully estimated, and the reflected signal can be equivalently written as

[0077]

[0078] Then the matched filter (MF) algorithm is used to estimate the Doppler and range parameters. The specific steps are shown in Table 1.

[0079] Table 1

[0080]

[0081] Step 202: The ISAC base station and the communication terminal fuse the angle and distance of each reference point respectively to obtain fused position information of each reference point.

[0082] In this embodiment, the ISAC base station and the communication terminal use the same method to perform calculation processing on the angle and distance of each reference point, so that the angle and distance of each reference point are linked, instead of using the angle and distance information directly. After this processing, even if the eavesdropper obtains the angle and distance information of the same reference point, since he does not know the specific method of fusing the angle and distance of each reference point, he still cannot crack the key generated by the angle and distance of each reference point in this embodiment, thereby improving the confidentiality of the key.

[0083] Specifically, the origin of the coordinate system of each reference point can be changed from the ISAC base station to any reference point, so that the coordinates of each reference point are transformed by utilizing the positional relationship between the reference points, so that the angle and distance information of the reference points are changed.

[0084] Step 203, the ISAC base station and the communication terminal divide the reference points into n groups based on the fused position information of each reference point, and encode the number of reference points in each group of reference points to obtain a first key; wherein n is a preset value.

[0085] In this embodiment, based on the fused position information of each reference point, each reference point is divided into n groups, and the number of reference points in each group is used for encoding, which can effectively utilize the randomness of the reference point position distribution and the fused position information. Grouping facilitates the control of the length of the key.

[0086] Step 204: The ISAC base station and the communication terminal respectively quantize and encode the channel characteristics between the ISAC base station and the communication terminal to obtain a second key.

[0087] In this embodiment, the channel characteristics between the ISAC base station and the communication terminal are reciprocal and random, that is, the ISAC base station and the communication terminal can directly obtain the same channel characteristics. The key generated in this way does not require key distribution and negotiation, and the key generated by quantization encoding using the channel characteristics is unique and has high security.

[0088] Step 205: The ISAC base station and the communication terminal respectively combine the first key and the second key to obtain a final key.

[0089] In this embodiment, the keys generated in two ways are combined to achieve the superposition of the security of the two keys, thereby further improving the security of the final key.

[0090] The embodiment of the present invention obtains information such as randomly distributed environmental nodes in the surrounding environment through the ISAC base station, takes it as a reference point, extracts the location information and sends it to the communication terminal. Both parties process the location information of the reference point in the same way and combine it with the channel characteristics to generate the final key. Compared with the prior art, it not only utilizes the randomness of the node information in the environment, but also integrates the various information of the nodes. Even if the eavesdropper obtains the same characteristics, it is difficult to form a key that is exactly the same as the final key, thereby improving the confidentiality of the key.

[0091] In a possible implementation, the ISAC base station and the communication terminal fuse the angle and distance of each reference point respectively to obtain fused position information of each reference point, including:

[0092] The ISAC base station and the communication terminal respectively use the ISAC base station as the origin and convert the polar coordinates of each reference point into Cartesian coordinates;

[0093] The ISAC base station and the communication terminal translate the Cartesian coordinates of each reference point based on the Cartesian coordinates of the first reference point to obtain the translated coordinates of each reference point; wherein the first reference point is a reference point specified by the ISAC base station among the reference points, and the translated coordinates of the first reference point are (0, 0);

[0094] The ISAC base station and the communication terminal respectively convert the translated coordinates of each reference point into polar coordinates as the fused position information of each reference point.

[0095] In this embodiment, the first reference point in this embodiment can be any one of the reference points, which is specified by the ISAC base station to ensure that the ISAC base station and the communication terminal use the same reference point as the first reference point. After determining the selected reference point, the ISAC base station sends the coordinates of the selected reference point to the communication terminal, and both parties then generate keys using the predetermined algorithm. The positioning information of the ISAC base station is based on itself as the origin, and the position of each reference point is defined as angle θ and distance d, which is defined as l k =(d k ,θ k ),k=1,2,...,L. The ISAC base station will l k After sending to the communication terminal, both parties perform the same operation.

[0096] First, transform the coordinates:

[0097] 1. Determine the coordinates of the new origin in the polar coordinate system (d1,θ1).

[0098] 2. Convert the polar coordinates (d,θ) of all points to Cartesian coordinates (x,y). This can be done using the following formula:

[0099] x=dcos(θ)

[0100] y=dsin(θ)

[0101] 3. Translate the Cartesian coordinates of each point and move the origin (0,0) to the new origin (d1cos(θ1),d1sin(θ1)).

[0102] 4. Convert the translated Cartesian coordinates to polar coordinates. This can be done using the following formula:

[0103]

[0104] θ=atan2(y,x)

[0105] Through the above steps, the location information of all reference points is converted into a measurement centered on the location of the first reference point. After this operation, the positioning information of the ISAC base station to the reference point, including the angle and distance, is fully utilized. Compared with some existing documents, although two features are also used for key generation, each feature is used separately for key generation, and finally the two keys are simply XORed or combined in other simple ways. Compared with this method, the combination method proposed in this embodiment makes the key more confidential. Even if the eavesdropper obtains the same two features, it is difficult to form a key that is exactly the same as that of the legitimate user and the base station, which greatly improves the confidentiality of the key.

[0106] In a possible implementation, the ISAC base station and the communication terminal divide the reference points into n groups based on the fused position information of the reference points, and encode the number of reference points in each group of reference points to obtain a first key, including:

[0107] The ISAC base station and the communication terminal divide each reference point into n angle intervals according to the coordinate angle in the fused position information of each reference point; wherein the angle range of each angle interval is equal, and each reference point in each angle interval is a group;

[0108] The ISAC base station and the communication terminal respectively use binary numbers with a length of m / n to represent the number of reference points in each group of reference points, and combine them to obtain a first key with a length of m; wherein m is a preset value.

[0109] In this embodiment, after the ISAC base station sends the selected surrounding reference point location information to the communication terminal, the communication terminal takes the first reference point as the origin, updates the location information of other reference points based on mathematical tools, calculates in which direction of the origin the locations of other reference points are located, and then divides the 360° range involved in the angle of each reference point into multiple intervals of equal size, calculates the number of reference points in each interval, and then represents different numbers with different multi-bit binary numbers. The base station also uses the same method to eventually form a preliminary key.

[0110] The traditional key length is between 128 and 512 bits, so n can be set to 24, and the entire 360° interval is divided into an interval of 15° each, for a total of 24 intervals. Then the number of reference points in each interval is calculated separately, and finally different numbers of reference points are represented by different 8-bit binary numbers to form a preliminary 192-bit key bit stream.

[0111] Although the channel estimation and equalization technology are adopted to ensure that the reference point location information obtained between the ISAC base station and the communication terminal is consistent to a large extent, there is still a low possibility that errors will occur during communication, resulting in deviations when calculating the number of reference points in the interval. Therefore, the encoding method of the number of reference points can be selected in the form of a combination of decimal remainder three Gray code and decimal empty six Gray code. This encoding method can make the two bit streams differ by only 2 bits when the number of reference points determined by the ISAC base station and the communication terminal in the same interval differs by 1, thereby reducing the mismatch rate of the key generated in the end, and at the same time satisfying a certain degree of bit stream randomness. Exemplarily, the codes generated corresponding to different numbers of reference points can be shown in Table 2.

[0112] Table 2

[0113] Reference points coding 0 00100000 1 01100001 2 01110011 3 01010010 4 01000110 5 11001110 6 11011010 7 11111011 8 11101001 ≥9 10101000

[0114] In a possible implementation, the ISAC base station and the communication terminal respectively combine the first key and the second key to obtain a final key, including:

[0115] The ISAC base station and the communication terminal respectively divide the second key into multiple segments of binary numbers with a length of q bits, and for each segment of binary numbers, use the binary digit that appears the most times in the segment of binary numbers to represent the segment of binary numbers, obtain m binary digits, and splice the m binary digits in the original order to obtain a compressed second key; wherein the second key is q times the length of the first key, m is the length of the first key, and q is a preset value;

[0116] The ISAC base station and the communication terminal perform XOR on the first key and the compressed second key respectively to obtain a final key.

[0117] In this embodiment, after channel estimation, the ISAC base station and the communication terminal can extract the amplitude of the channel observation value as the channel feature for key generation. Both parties can use the amplitude information to generate the key in the following manner.

[0118] The key generation based on the channel amplitude characteristics needs to be quantized and encoded. Specifically, the more popular uniform quantization technology can be used, and the following formula can be used for quantization encoding:

[0119] Y=Q(X)X∈(d i ,d i+1 ).

[0120] Although uniform quantization is easy to implement, increasing the number of quantization bits will significantly reduce the performance of the algorithm because the bit mismatch rate between two communication nodes will increase. In this regard, a coding algorithm is used in this embodiment to solve this problem. Among them, each uniform quantized value is encoded with multiple values, each value contains multiple bits, and the multiple bits here also use the decimal three-bit Gray code proposed above to reduce the bit mismatch rate. Specifically, q can be set to 5, and the second key K generated based on the channel amplitude characteristics h is 960 bits, which is the first key K l 5 times, this is done to give the subsequent K l With K h Prepare for the combination.

[0121] So far, the ISAC base station and the communication terminal have generated the first key and the second key based on the reference point position characteristics and the channel amplitude characteristics. Due to the channel estimation and equalization, the first key K generated based on the reference point position is l The key mismatch rate is low, and the two parties are basically consistent, but the second key K generated based on the channel amplitude characteristics h Due to the influence of noise and delay, and without information reconciliation, the second K h There will be a higher bit mismatch rate. Therefore, if a simple addition scheme is adopted, it will result in K l The low key mismatch rate is wasted, and the final key K generated needs to be reconciled, which increases the complexity of the key generation algorithm. Therefore, in this embodiment, the following method is used to reconcile K l and K h To combine:

[0122] K hEvery 5 bits in K are combined into one bit. The rule is that among these 5 bits, the binary number with the most occurrences is used to represent these five bits. For example, 00010 is represented by bit 0. In this way, even if there is an error in one bit and it becomes 00110, the final result is still 0, which can reduce the key mismatch caused by channel errors to a certain extent. After conversion, K l and K h They have the same number of bits, and finally use the following formula to generate the final key K:

[0123] K=K l ⊕K h

[0124] In addition, although the key negotiation leaks very little information, an eavesdropper can still use this leaked information to guess the rest of the key. Therefore, confidentiality enhancement is needed. The role of confidentiality enhancement is to compress the partially secure key into information that is almost inaccessible to eavesdroppers through a compression function. Usually, the bit stream processed by this technology is shorter in length, but has higher entropy. To this end, the ISCA base station and the communication terminal can both apply a universal hash function randomly selected from a set of hash functions known to both the ISCA base station and the communication terminal. The ISCA base station sends the number of the selected hash function to the communication terminal so that the communication terminal can use the same hash function.

[0125] In a possible implementation, the ISAC base station obtains location information of multiple reference points in the surrounding environment, including:

[0126] The ISAC base station allocates radar power and communication power based on the number of communication terminals, and scans the surrounding environment based on the radar power to obtain the location information of multiple reference points in the surrounding environment.

[0127] In this embodiment, the radar detection function of the ISAC base station is used to locate the surrounding nodes. Compared with traditional radar detection, the base station also needs to communicate with other users during the positioning process. The signal of the ISAC base station's radar detection also contains communication information. Communication work is performed simultaneously during the process of detecting the reference point position. The power resources of the base station are limited, so the power allocation between radar detection and communication also needs to be considered.

[0128] On the one hand, the power distribution of the base station will affect the range of radar detection. When the power is high, the detection range will be larger, so more reference nodes can be selected, and the standard deviation of the reference node position can be guaranteed to be above the acceptable range. On the other hand, power will also affect the quality of base station communication. Therefore, the balance of power distribution in this embodiment is mainly based on the radar detection distance Dmax and the rate that the communication terminal can achieve.

[0129] First, analyze the radar positioning range. The ISAC base station transmits the detection signal Pt with power. Assuming that the gain of the transmitting antenna is G and the reflection cross-sectional area of ​​the reference node target is Q, the power at the reference node target at a distance of D is: After the target intercepts the incident wave power, it radiates evenly to the entire space. The radiation power per unit solid angle is The reflected signal reaches the receiver after a certain distance, and the power can be expressed as: Pr represents the signal power received by the receiver. If Pr is replaced by the minimum power of the echo signal that the receiver can detect, Dmax can be expressed as the maximum distance that the radar can detect:

[0130] Next, we analyze the total user communication volume. Assuming there are r communication terminals in the scenario, the SNRr of each communication terminal is: The achievable sum rate of all communication terminals can be expressed as follows:

[0131] Under the requirement of radar detection distance, we hope to maximize the total communication rate of users, and construct the optimization problem as follows:

[0132]

[0133] P min ≤P i ≤P max ,i=1,…,r

[0134] R(p r )≥Γ c

[0135] D max ≥150

[0136] By solving the above model, we can obtain the power allocation scheme for ISCA base station to perform radar detection and communication.

[0137] In a possible implementation, the ISAC base station obtains location information of multiple reference points in the surrounding environment and sends the location information of each reference point to the communication terminal, including:

[0138] If the number of reference points in the surrounding environment is greater than a preset threshold, a preset proportion of reference points are randomly removed, and the position information of the remaining reference points is sent to the communication terminal.

[0139] In this embodiment, in the subsequent key generation algorithm, since the number of targets that need to be detected, such as communication terminals near the base station and randomly distributed environmental nodes, is different at every moment, when the surrounding points to be detected are too dense and too many, these large amounts of location information will increase the subsequent calculation burden, and the degree of enhancement of the generated key and authentication performance is also limited. Therefore, after the ISAC base station completes the radar positioning of the surrounding reference points, it is necessary to select a certain number of reference point positions according to certain principles for key generation.

[0140] Specifically, the reference nodes can be selected according to the positions and numbers of the reference nodes. For example, a value can be randomly selected within a preset range of node numbers, and then the number of nodes can be randomly selected from the nodes in the environment as reference nodes to ensure the randomness of the number and positions of the reference points.

[0141] In a possible implementation manner, the ISAC base station sends the location information of each reference point to the communication terminal, including:

[0142] The ISAC base station performs channel estimation and equalization on the communication terminal to obtain equalizer coefficients, and uses the equalizer coefficients to send the position information of each reference point to the communication terminal.

[0143] In this embodiment, the purpose of channel estimation and equalization is twofold. First, the ISAC base station and the communication terminal can obtain the channel information between the two parties by performing channel estimation. In order to estimate the channel parameter h, the two legitimate communicating parties Alice and Bob must send known detection signals to each other. Then each party can use the received signal and the detection signal to calculate the estimated h(h). The estimated h a and h b The probabilities are not equal in all cases, partly because of the independent noise terms and partly because of the time lag τ. However, if Alice and Bob send probe signals to each other quickly enough, that is, if τ = t2 - t1 is small, they can be highly correlated.

[0144] Although the eavesdropper Eve can hear the detection signal sent by each user, the signal she receives is completely different. Through channel estimation, the ISAC base station and the communication terminal can obtain the channel characteristics between the two. Currently, the amplitude characteristics of the channel are usually used, which can be used to generate keys. Finally, the keys generated based on the position and channel are combined to improve the key entropy and form a higher performance key. On the other hand, through channel estimation and equalization, the probability of positioning information errors due to wireless transmission can be greatly reduced in the process of the ISAC base station sending the reference point location information to the communication terminal. The original data can be restored using equalization technology, and the data accuracy can be greatly improved before decoding, thereby reducing the probability of reference point location information errors at the communication terminal and reducing the mismatch rate of subsequent key generation. At the same time, the key reconciliation part of the traditional key generation process can be omitted, reducing the complexity of key generation.

[0145] In this embodiment, pilot-based channel estimation is adopted, and the method is mainly divided into two steps. The first step is to obtain the channel response at the pilot point, and the second step is to obtain the channel estimation results of all subcarrier positions through a reasonable mathematical interpolation method based on the channel estimation results at the pilot point, thereby completing the channel estimation.

[0146] The specific steps are as follows:

[0147] Channel estimation: The MMSE-based channel estimation algorithm is selected. The cost function based on this method is expressed as:

[0148]

[0149] To minimize the cost function, define:

[0150]

[0151] Taking the partial derivative of the cost function and making it equal to 0, we can obtain:

[0152] R HH is the autocorrelation function of the channel impulse response, R HH =E[HH H ]=[r m,n ].

[0153] MMSE channel estimation algorithm obtains The estimated value expression can be simplified to:

[0154] Equalization: MMSE equalization takes into account the additive noise of the channel, so that the effects of ICI and additive noise can be eliminated at the same time. The goal of MMSE equalization is to minimize the MSE between the signal and the equalizer output, that is, to choose a suitable F(K) so that Minimum, that is

[0155] The coefficient expression of the equalizer is derived as

[0156] As can be seen from the above, the innovative features of the embodiments of the present invention include:

[0157] 1. It is proposed to use the two-dimensional information of location features, that is, to use angle and distance at the same time as a physical layer key generation feature.

[0158] 2. It is proposed to use coordinate transformation to fuse the two features of angle and distance. Both the ISAC base station and the user convert the location information centered on the base station into coordinates centered on a certain reference point. In this way, the distance and angle information of each reference point are changed accordingly.

[0159] 3. A new position feature extraction scheme is proposed, which takes the number of reference points in different intervals of the transformed coordinates as features, making full use of the distance and angle information of each reference point.

[0160] 4. A key generation scheme in the ISAC scenario is proposed, which uses the synaesthesia function of the ISAC base station to obtain the location information of surrounding reference points.

[0161] 5. A new key combination scheme is proposed, which combines multiple bits of the channel feature generated key with one bit of the position feature to combine the advantages of both.

[0162] 6. Balance the power allocation of ISAC base stations. Under the condition of meeting the detection distance requirements, the power allocation of ISAC base stations is balanced.

[0163] The beneficial effects of this patent application include:

[0164] 1. Using the constantly changing positions of reference points around as key generation features, the angle and distance information of the reference points can be used simultaneously to improve the entropy of the generated key.

[0165] 2. The types of available physical layer key generation features have been enriched.

[0166] 3. Use the radar detection function of the ISAC base station to locate surrounding reference points, reduce calculation complexity, and save channel resources.

[0167] 4. Utilize both location features and channel features simultaneously, combining the advantages of low key mismatch rate of location features and high key entropy of channel features.

[0168] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0169] The following is an embodiment of the device of the present invention. For details not described in detail, reference may be made to the corresponding method embodiments described above.

[0170] Figure 3 The schematic diagram of the structure of the key generation system based on synaesthesia-oriented authentication provided by an embodiment of the present invention is shown. For the convenience of explanation, only the part related to the embodiment of the present invention is shown, which is described in detail as follows:

[0171] like Figure 3 As shown, the key generation system 3 based on synaesthesia-oriented authentication includes an ISAC base station 31 and a communication terminal 32;

[0172] The ISAC base station 31 is used to obtain the location information of multiple reference points in the surrounding environment and send the location information of each reference point to the communication terminal 32; wherein the location information includes angle and distance;

[0173] The ISAC base station 31 and the communication terminal 32 are used to fuse the angle and distance of each reference point to obtain the fused position information of each reference point;

[0174] The ISAC base station 31 and the communication terminal 32 are respectively used to divide each reference point into n groups based on the fused position information of each reference point, and encode the number of reference points in each group of reference points to obtain a first key; wherein n is a preset value;

[0175] The ISAC base station 31 and the communication terminal 32 are respectively used to quantize and encode the channel characteristics between the ISAC base station and the communication terminal to obtain a second key;

[0176] The ISAC base station 31 and the communication terminal 32 are respectively used to combine the first key and the second key to obtain a final key.

[0177] In a possible implementation, the ISAC base station 31 and the communication terminal 32 are specifically used for:

[0178] Taking the ISAC base station as the origin, convert the polar coordinates of each reference point into Cartesian coordinates;

[0179] Based on the Cartesian coordinates of the first reference point, the Cartesian coordinates of each reference point are translated to obtain the translated coordinates of each reference point; wherein the first reference point is a reference point specified by the ISAC base station among the reference points, and the translated coordinates of the first reference point are (0, 0);

[0180] The translated coordinates of each reference point are converted into polar coordinates as the fused position information of each reference point.

[0181] In a possible implementation, the ISAC base station 31 and the communication terminal 32 are specifically used for:

[0182] According to the coordinate angle in the fusion position information of each reference point, each reference point is divided into n angle intervals; wherein the angle range of each angle interval is equal, and each reference point in each angle interval is a group;

[0183] The number of reference points in each group of reference points is represented by a binary number of length m / n, and the numbers are combined to obtain a first key of length m; wherein m is a preset value.

[0184] In a possible implementation, the ISAC base station 31 and the communication terminal 32 are specifically used for:

[0185] The second key is divided into multiple segments of binary numbers with a length of q bits, and for each segment of binary numbers, the binary digit that appears the most times in the segment of binary numbers is used to represent the segment of binary numbers, to obtain m binary digits, and the m binary digits are concatenated in the original order to obtain a compressed second key; wherein the second key is q times the length of the first key, m is the length of the first key, and q is a preset value;

[0186] The first key and the compressed second key are XORed to obtain a final key.

[0187] In a possible implementation, the ISAC base station 31 is specifically used for:

[0188] Radar power and communication power are allocated based on the number of communication terminals, and the surrounding environment is scanned based on the radar power to obtain the location information of multiple reference points in the surrounding environment.

[0189] In a possible implementation, the ISAC base station 31 is specifically used for:

[0190] If the number of reference points in the surrounding environment is greater than a preset threshold, a preset proportion of reference points are randomly removed, and the position information of the remaining reference points is sent to the communication terminal.

[0191] In a possible implementation, the ISAC base station 31 is specifically used for:

[0192] The ISAC base station 31 performs channel estimation and equalization on the communication terminal 32 to obtain equalizer coefficients, and uses the equalizer coefficients to send the position information of each reference point to the communication terminal 32.

[0193] The embodiment of the present invention obtains information such as randomly distributed environmental nodes in the surrounding environment through the ISAC base station, takes it as a reference point, extracts the location information and sends it to the communication terminal. Both parties process the location information of the reference point in the same way and combine it with the channel characteristics to generate the final key. Compared with the prior art, it not only utilizes the randomness of the node information in the environment, but also integrates the various information of the nodes. Even if the eavesdropper obtains the same characteristics, it is difficult to form a key that is exactly the same as the final key, thereby improving the confidentiality of the key.

[0194] The embodiment of the present invention further provides an ISAC base station, which is used to implement the steps of the ISAC base station in the above embodiment, namely, steps 201 to 205.

[0195] The embodiment of the present invention further provides a communication terminal, which is used to implement the steps of the communication terminal in the above embodiment, namely, step 202 to step 205.

[0196] Figure 4 is a schematic diagram of a communication terminal provided by an embodiment of the present invention. Figure 4 As shown, the communication terminal 4 of this embodiment includes: a processor 40, a memory 41, and a computer program 42 stored in the memory 41 and executable on the processor 40. When the processor 40 executes the computer program 42, the steps in the above-mentioned key generation method embodiments based on synaesthesia-oriented authentication are implemented, for example Figure 2 Alternatively, when the processor 40 executes the computer program 42, the functions of each module / unit in the above-mentioned system embodiments are realized, for example, Figure 3 Functionality of the modules / units 32 shown.

[0197] Exemplarily, the computer program 42 may be divided into one or more modules / units, which are stored in the memory 41 and executed by the processor 40 to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program 42 in the communication terminal 4.

[0198] The communication terminal 4 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The communication terminal 4 may include, but is not limited to, a processor 40 and a memory 41. Those skilled in the art will appreciate that Figure 4 It is only an example of the communication terminal 4 and does not constitute a limitation on the communication terminal 4. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the communication terminal may also include input and output devices, network access devices, buses, etc.

[0199] The processor 40 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0200] The memory 41 may be an internal storage unit of the communication terminal 4, such as a hard disk or memory of the communication terminal 4. The memory 41 may also be an external storage device of the communication terminal 4, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the communication terminal 4. Further, the memory 41 may also include both an internal storage unit and an external storage device of the communication terminal 4. The memory 41 is used to store the computer program and other programs and data required by the communication terminal. The memory 41 may also be used to temporarily store data that has been output or is to be output.

[0201] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0202] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0203] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0204] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0205] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0206] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0207] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-mentioned key generation method embodiments based on synaesthesia-oriented authentication can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practices in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practices, computer-readable media does not include electrical carrier signals and telecommunication signals.

[0208] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A key generation method based on synaesthesia-oriented authentication, characterized in that: Applied to an ISAC system, the system comprising an ISAC base station and a communication terminal; the method comprising: The ISAC base station obtains the location information of multiple reference points in the surrounding environment and sends the location information of each reference point to the communication terminal; wherein the location information includes angle and distance; The ISAC base station and the communication terminal fuse the angle and distance of each reference point respectively to obtain fused position information of each reference point; The ISAC base station and the communication terminal respectively divide the reference points into n groups based on the fused position information of each reference point, and encode the number of reference points in each group of reference points to obtain a first key; wherein n is a preset value; The ISAC base station and the communication terminal respectively quantize and encode the channel characteristics between the ISAC base station and the communication terminal to obtain a second key; The ISAC base station and the communication terminal respectively combine the first key and the second key to obtain a final key.

2. The key generation method based on synaesthesia-oriented authentication according to claim 1 is characterized in that: The ISAC base station and the communication terminal fuse the angle and distance of each reference point respectively to obtain fused position information of each reference point, including: The ISAC base station and the communication terminal respectively convert polar coordinates of each reference point into Cartesian coordinates with the ISAC base station as the origin; The ISAC base station and the communication terminal translate the Cartesian coordinates of each reference point based on the Cartesian coordinates of the first reference point to obtain the translated coordinates of each reference point; wherein the first reference point is a reference point specified by the ISAC base station among the reference points, and the translated coordinates of the first reference point are (0, 0); The ISAC base station and the communication terminal respectively convert the translated coordinates of each reference point into polar coordinates as the fused position information of each reference point.

3. The key generation method based on synaesthesia-oriented authentication according to claim 2 is characterized in that: The ISAC base station and the communication terminal respectively divide the reference points into n groups based on the fused position information of each reference point, and encode the number of reference points in each group of reference points to obtain a first key, including: The ISAC base station and the communication terminal divide each reference point into n angle intervals according to the coordinate angle in the fused position information of each reference point; wherein the angle range of each angle interval is equal in size, and each reference point in each angle interval is a group; The ISAC base station and the communication terminal respectively use binary numbers with a length of m / n to represent the number of reference points in each group of reference points, and combine them to obtain a first key with a length of m; wherein m is a preset value.

4. The method for generating a key based on synaesthesia-oriented authentication according to claim 1, characterized in that: The ISAC base station and the communication terminal respectively combine the first key and the second key to obtain a final key, including: The ISAC base station and the communication terminal respectively divide the second key into multiple segments of binary numbers with a length of q bits, and for each segment of binary numbers, use the binary digit that appears the most times in the segment of binary numbers to represent the segment of binary numbers, obtain m binary digits, and splice the m binary digits in the original order to obtain a compressed second key; wherein, the second key is q times the length of the first key, m is the length of the first key, and q is a preset value; The ISAC base station and the communication terminal perform XOR on the first key and the compressed second key respectively to obtain a final key.

5. The method for generating a key based on synaesthesia-oriented authentication according to claim 1, characterized in that: The ISAC base station obtains location information of multiple reference points in the surrounding environment, including: The ISAC base station allocates radar power and communication power based on the number of communication terminals, and scans the surrounding environment based on the radar power to obtain location information of multiple reference points in the surrounding environment.

6. The method for generating a key based on synaesthesia-oriented authentication according to claim 1, characterized in that: The ISAC base station acquires location information of multiple reference points in the surrounding environment and sends the location information of each reference point to the communication terminal, including: If the number of reference points in the surrounding environment is greater than a preset threshold, a preset proportion of reference points are randomly removed, and the position information of the remaining reference points is sent to the communication terminal.

7. The method for generating a key based on synaesthesia-oriented authentication according to claim 1, characterized in that: The ISAC base station sends the location information of each reference point to the communication terminal, including: The ISAC base station performs channel estimation and equalization on the communication terminal to obtain equalizer coefficients, and uses the equalizer coefficients to send position information of each reference point to the communication terminal.

8. A key generation system based on synaesthesia-oriented authentication, characterized in that: Including ISAC base station and communication terminal; The ISAC base station is used to obtain the location information of multiple reference points in the surrounding environment and send the location information of each reference point to the communication terminal; wherein the location information includes angle and distance; The ISAC base station and the communication terminal are respectively used to fuse the angle and distance of each reference point to obtain fused position information of each reference point; The ISAC base station and the communication terminal are respectively used to divide each reference point into n groups based on the fused position information of each reference point, and encode the number of reference points in each group of reference points to obtain a first key; wherein n is a preset value; The ISAC base station and the communication terminal are respectively used to quantize and encode the channel characteristics between the ISAC base station and the communication terminal to obtain a second key; The ISAC base station and the communication terminal are respectively used to combine the first key and the second key to obtain a final key.

9. The synaesthesia-oriented authentication-based key generation system according to claim 8, characterized in that: The ISAC base station and the communication terminal are specifically used for: Taking the ISAC base station as the origin, converting the polar coordinates of each reference point into Cartesian coordinates; Based on the Cartesian coordinates of the first reference point, the Cartesian coordinates of each reference point are translated to obtain the translated coordinates of each reference point; wherein the first reference point is a reference point specified by the ISAC base station among the reference points, and the translated coordinates of the first reference point are (0, 0); The translated coordinates of each reference point are converted into polar coordinates as the fused position information of each reference point.

10. The synaesthesia-oriented authentication-based key generation system according to claim 9, characterized in that: The ISAC base station and the communication terminal are specifically used for: According to the coordinate angle in the fusion position information of each reference point, each reference point is divided into n angle intervals; wherein the angle range of each angle interval is equal, and each reference point in each angle interval is a group; The number of reference points in each group of reference points is represented by a binary number of length m / n, and the numbers are combined to obtain a first key of length m; wherein m is a preset value.

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