CN105828432A - Efficient privacy protection method for ranging and locating of anchor node - Google Patents

Abstract

The invention relates to an efficient privacy protection method for ranging and locating of an anchor node. The method comprises the following steps: the anchor node executes a ranging process from the anchor node to a target node to acquire a ranging information set D; constructing a coefficient matrix A and a ranging matrix B according to location information of the anchor node and the ranging information set D; separately decomposing the matrix A and the matrix B row by row, and performing cluster decomposition on a middle item ATA and a middle item ATB; performing privacy protection summation and privacy protection adjacent product summation based on the middle item decomposition results; and calculating the location of the target node using the privacy protection calculation results of the ATA and the ATB. The efficient privacy protection method for ranging and locating of the anchor node solves the privacy problem in ranging and locating of the anchor node, and does not use a homomorphic encryption algorithm, so that the calculation cost and the communication cost are low and the efficiency of the privacy protection method can be improved while the location privacy of a user is protected.

Description

Efficient privacy protection method for anchor node ranging and positioning

Technical Field

The invention relates to the field of positioning and privacy protection, in particular to a high-efficiency privacy protection method for anchor node ranging positioning.

Background

With the continuous development of mobile communication network technology and ubiquitous computing technology, Location-based services (LBS) is becoming more and more important. Positioning technology has attracted extensive attention from researchers all over the world as a basis for location-aware computing and location-based services.

Anchor node ranging positioning is one of the most common positioning techniques. The anchor node ranging and positioning technology comprises two types of devices: a plurality of anchor node devices (e.g., smartphones) and a target node device (e.g., laptop, sensor, tablet). The anchor node ranging and positioning technology adopts three-stage mode. The first stage is an anchor node discovery process, a target node recruits a mobile anchor node through broadcasting a hello message at a communication interface of the target node, and the smart phone receives the hello message and replies the hello message to the target node so as to become the anchor node. The anchor node needs to satisfy two conditions: (1) the anchor node is within one-hop communication range of the target node for ranging. This condition is easily satisfied because the anchor node can receive the hello packet sent by the target node. (2) The anchor node must have its own location information. The target node can add an expected value of the position accuracy of the anchor node into the hello message, and only the anchor node meeting the accuracy can reply to the target node. In the second stage, the anchor node performs a ranging process, and the anchor node estimates the distance between the anchor node and the target node, and the ranging can be based on various methods, such as a sound wave ranging method based on time arrival difference and a ranging method based on signal reception strength. The third stage is position calculation, and the position calculation is carried out by using a multilateral positioning method according to the ranging information and the position information of the anchor node.

It can be seen from the process of the ranging and positioning of the anchor node that the ranging and positioning of the anchor node requires the anchor node to measure the distance between the anchor node and the target node, which may cause the anchor node to communicate to estimate the position of the target node, resulting in the leakage of the position information of the target node, and thus it can be seen that the ranging and positioning of the anchor node is more suitable for the scenario where the target node is not in a strong position concern. Although the anchor node ranging and positioning is considered as a practical positioning algorithm, the anchor node ranging and positioning has a potential privacy disclosure problem, and the privacy information of the target node user and the anchor node user can be disclosed. First, location information for the anchor node user may be leaked. Since the target node location calculation needs to use the location information and ranging information of the anchor node as inputs, the location information of the anchor node may be acquired by other anchor nodes to cause a security problem. Secondly, the position calculation result of the target node user may not be only known by the target node, but also other anchor nodes may obtain the positioning result, thereby causing privacy leakage. Finally, directly applying the existing homomorphic encryption algorithm for privacy protection causes a large calculation cost and communication cost, which is not favorable for popularization and use of the privacy protection method.

Taoetal, in the section "IEEE/ACCT RANSACTION SOnNetworking" of 2015 23(5), published an article with the name of "protective Multi-layer Locallocalization privacy in privacy Environments", and relates to a distance measuring and positioning privacy protection method for an anchor node in a disclosed multi-party privacy protection positioning method. The method does not use a homomorphic encryption algorithm, and can protect the privacy information in the anchor node ranging and positioning process. However, in the implementation process of the method, a specific anchor node needs to be selected to calculate the privacy information of all anchor nodes, which is equivalent to the method with the help of the thought of a trusted third party. The method of selecting a specific anchor node as a trusted third party in the privacy protection positioning process causes unfair status among the anchor nodes on one hand, and also causes huge calculation cost and communication cost for the specific anchor node on the other hand. The consequence of using a specific anchor node to calculate all the privacy information of the anchor node is not beneficial to the practical application of the distance measurement and positioning privacy protection method of the anchor node.

Compared with the method that the privacy leakage problem in the anchor node ranging and positioning process is solved by directly using the homomorphic encryption theory, the efficient privacy protection method for directly designing the anchor node ranging and positioning can protect the position privacy information of the user and reduce the calculation cost and the communication cost of the privacy protection method. In addition, the problem of unfair status among anchor nodes is not caused by calculating the adjacent product sum through privacy protection summation and privacy protection, and huge calculation cost and communication cost are not caused for a certain anchor node.

Disclosure of Invention

The invention aims to provide an anchor node ranging and positioning privacy protection method which can protect position privacy information of a user and can reduce calculation cost and communication cost of the privacy protection method.

To this end, the technical scheme provided by the invention is an efficient privacy protection method for ranging and positioning of an anchor node, which comprises the following steps:

s1, an anchor node executes a ranging process from the anchor node to a target node to obtain a ranging information set D;

s2, constructing a coefficient matrix A and a ranging matrix B according to anchor node position information and the ranging information set D;

s3, performing line-by-line decomposition on the matrix A and the matrix B respectively, and performing line-by-line decomposition on the intermediate item A^TA and the intermediate term A^TB, performing clustering decomposition;

s4, carrying out privacy protection summation calculation and privacy protection adjacent product summation calculation aiming at the intermediate item decomposition result;

s5, utilizing A^TA and A^TAnd B, performing privacy protection calculation, and performing position calculation on the target node.

Further, in the foregoing S1, it is assumed that there are m anchor nodes in the region, and for the anchor nodes i, 1, …, m, d_i0Representing an estimate of the distance of the anchor node i to the target node 0, i.e. ranging information d_i0Obtaining a ranging information set D ═ D after the ranging phase is finished for the privacy information of the anchor node i_i0,i＝1…m}。

Further, in the aforementioned S2, the process of constructing the coefficient matrix a and the ranging matrix B is as follows:

s21, constructing a coefficient matrix A, and assuming the position of an anchor node i(x_i1,x_i2,…,x_in) Where n represents the dimension of the space, the matrix a is defined as:

s22, constructing a ranging matrix B, wherein the definition of the matrix B is as follows according to the ranging information set D and the position coordinate information:

$B\stackrel{def}{=}\left[\begin{array}{c}{\mathrm{\Σ}}_{j=1}^n(x_{1j}^2-x_{2j}^2)-(d_{10}^2-d_{20}^2)\\ {\mathrm{\Σ}}_{j=1}^n(x_{2j}^2-x_{3j}^2)-(d_{20}^2-d_{30}^2)\\ \·\\ \·\\ \·\\ {\mathrm{\Σ}}_{j=1}^n(x_{m-1j}^2-x_{mj}^2)-(d_{m-10}^2-d_{m0}^2)\end{array}\right].$

further, the step S3 specifically includes:

s31, decomposing each row of the matrix A, namely:

$A=\left[\begin{array}{c}{A}_1\\ \·\\ \·\\ \·\\ A_{m-1}\end{array}\right]$

wherein A is_i＝2[x_i1-x_i+11…x_in-x_i+1n]＝2(x_i-x_i+1),i＝1,…,m-1；

S32, decomposing each row of the matrix B, namely:

$B=\left[\begin{array}{c}{b}_1\\ \·\\ \·\\ \·\\ b_{m-1}\end{array}\right]$

wherein,

s33, the intermediate item A^TA clustering decomposition, according to the decomposition result of matrix A, for A^TA, decomposing, so that the vector product in the first class of the decomposed result only contains the privacy information of a single anchor node, and the vector product in the second class only contains the privacy information of adjacent anchor nodes, namely:

A^TA＝V₁-V₂

wherein,

s34, the intermediate item A^TB clustering decomposition, according to the decomposition results of the matrixes A and B, carrying out A clustering decomposition on the matrixes^TB, decomposing is carried out, so that the decomposed vector product in the first class only contains the privacy information of a single anchor node, and the vector product in the second class only contains the privacy information of adjacent anchor nodes, namely:

A^TB＝U₁-U₂

wherein,

further, the aforementioned S4 further includes:

s41, the intermediate item A^TV of A decomposition result₁Performing privacy protection summation calculation on the intermediate item A^TU of B decomposition result₁Carrying out privacy protection summation calculation;

s42, the intermediate item A^TV of A decomposition result₂Performing privacy protection on the adjacent product sum calculation, and performing intermediate term A^TU of B decomposition result₂And carrying out privacy protection adjacent product summation calculation.

Still further, the aforementioned privacy preserving summation calculation comprises: suppose M_i(i-1, …, m-1) is the privacy information at anchor node i, then the privacy-preserving sum, i.e. privacy-preserving computationThe anchor node i (i-1, …, m-1) generates (m-1) random matricesk＝1,…,m-1，Anchor node i reservationThe rest matrixes are sent to corresponding (m-2) nodes, and the anchor node i adds the matrixes received by the anchor node i and sent by other nodes with the reserved matrixes to construct a matrixWhere P is_iIs a random matrix, andanchor node i send α_i＝M_i+P_iTo the target node 0, the target node 0 calculates according to the received informationHere α is the result of the privacy preserving sum computation.

The privacy preserving neighboring product sum calculation comprises: suppose M_i(i-1, …, m-1) is privacy information at anchor node i, and the privacy protection is a sum of adjacent products, i.e. privacy protection calculationAnchor node i (i-1, …, m-1) generationWill be provided withIs reserved, willSending the random to the node i +1, and receiving the random sent by the anchor node i +1 by the anchor node iNumber ofConstructing random numbersAnchor node i +1 generationWill be provided withIs reserved, willSending the random number to a node i, and receiving the random number sent by the anchor node i +1Constructing random numbersAnchor node i sendTo target node 0, anchor node i +1 sendsTo target node 0, based on the received information, target node 0 calculates β_i,i+1＝β_iβ_i+1β obtained by calculation_i,i+1(i-1, …, m-1), target node 0 calculationHere β is the result of the neighbor product sum computation for privacy protection.

Finally, the aforementioned S5 includes: summing computation and privacy with privacy protectionProtection of the intermediate term A of pairs of adjacent product-sum calculations^TA and the intermediate term A^TB, carrying out privacy protection calculation, and assuming that calculation results are respectively omega and psi, the position of the target node is

Has the advantages that: the efficient privacy protection method for anchor node ranging and positioning, provided by the invention, does not need to use a homomorphic encryption algorithm, can protect the privacy information of all users in the anchor point ranging and positioning process, and has lower calculation cost, communication cost and execution time. In addition, the efficient privacy protection method for anchor node ranging and positioning belongs to a completely distributed method, and each anchor node is equal in position, and calculation cost, communication cost and execution time are equal.

Drawings

Fig. 1 is a flow diagram of an efficient privacy protection method for anchor node ranging location.

Fig. 2 is a flow chart of a privacy preserving sum computation.

Figure 3 is a flow diagram of privacy preserving neighbor product sum computation.

Fig. 4 is an analysis result diagram describing the relationship between the calculation cost and the number m of anchor nodes in the present invention.

Fig. 5 is a diagram illustrating an analysis result of a relationship between a communication cost and the number m of anchor nodes in the present invention.

Fig. 6 is a diagram illustrating the analysis result of the relationship between the execution time and the number m of anchor nodes in the present invention.

Detailed Description

Specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. In the drawings, the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. An embodiment including simulation results is also provided and described with reference to the drawings, but the embodiment is exemplary and intended to be illustrative of the present invention and should not be construed as limiting the present invention.

The invention relates to the field of positioning and privacy protection, in particular to a high-efficiency privacy protection method for anchor node ranging positioning. The invention utilizes a matrix decomposition idea, combines an anchor node distance measurement positioning process, and solves the adjacent product sum calculation based on privacy protection sum calculation and privacy protection, thereby realizing the invention which has lower calculation cost and communication cost and carries out privacy protection on the information of all the participated users.

As shown in fig. 1, the efficient privacy protection method for anchor node ranging and positioning according to the embodiment of the present invention includes the following steps.

S1, the anchor node executes the ranging process from the anchor node to the target node to obtain a ranging information set D

The anchor node estimates its distance to the target node and takes the ranging information as privacy information. Ranging may be based on a variety of methods, for example, if the anchor point and the target device are in the same Basic Service Set (BSS), a Time-of-arrival (ToA) based acoustic ranging method may be used to obtain accurate ranging. In addition, if the anchor point is far away from the target node, a Radio Frequency (RF) ranging method, such as RSS (received signal strength) based ranging, may be used. Specifically, assuming that there are m anchor nodes and one target node in a region, for anchor node i ═ 1, …, m, d_i0Representing an estimate of the distance of the anchor node i to the target node 0, i.e. ranging information d_i0Is the privacy information of the anchor node i. After the ranging process is finished, obtaining a ranging information set D ═ { D ═ D_i0I-1 … m, for each anchor node i, a ranging message d is obtained_i0And the ranging information is privacy information of the anchor node i.

And S2, constructing a coefficient matrix A and a ranging matrix B according to the anchor node position information and the ranging information set D. Specifically, the method further comprises the following steps:

s21, constructing a coefficient matrix A

In order to construct the coefficient matrix, location information of the anchor node needs to be acquired. When selecting the anchor node, the anchor node with the own location information must be selected, so that all the anchor nodes participating in positioning have the own location information. In particular, assume the location of anchor node i(x_i1,x_i2,…,x_in) Where n denotes the dimension of the space (n ═ 2 denotes a two-dimensional space), the matrix a is defined as:

s22, constructing a ranging matrix B

In order to construct the ranging matrix, position information of the anchor node and distance information between the anchor node and the target node need to be acquired. As known from step S1, the ranging information is anchor node privacy information. Therefore, according to the ranging information and the position coordinate information, the matrix B is defined as:

$B\stackrel{def}{=}\left[\begin{array}{c}{\mathrm{\Σ}}_{j=1}^n(x_{1j}^2-x_{2j}^2)-(d_{10}^2-d_{20}^2)\\ {\mathrm{\Σ}}_{j=1}^n(x_{2j}^2-x_{3j}^2)-(d_{20}^2-d_{30}^2)\\ \·\\ \·\\ \·\\ {\mathrm{\Σ}}_{j=1}^n(x_{m-1j}^2-x_{mj}^2)-(d_{m-10}^2-d_{m0}^2)\end{array}\right].$

s3, decomposing the matrix A and the matrix B according to rows and carrying out intermediate item A^TA and the intermediate term A^TAnd B, performing clustering decomposition. Specifically, the method further comprises the following steps:

s31, decomposing each row of the matrix A

According to the structure of the coefficient matrix a, it can be seen that each row only contains information of two anchor nodes. The matrix a is thus decomposed in row units, each row being a separate vector. In particular, the amount of the solvent to be used,

$A=\left[\begin{array}{c}{A}_1\\ \·\\ \·\\ \·\\ A_{m-1}\end{array}\right]$

wherein A is_i＝2[x_i1-x_i+11…x_in-x_i+1n]＝2(x_i-x_i+1) I is 1, …, m-1. As can be seen from the decomposition result, each element of the matrix a only contains the private information of two neighboring anchor nodes.

S32, decomposing each row of the matrix B

According to the structure of the ranging matrix B, it can also be found that each row contains only information of two anchor nodes. The matrix B is thus also decomposed in units of rows, each row being a separate element. In particular, the amount of the solvent to be used,

$B=\left[\begin{array}{c}{b}_1\\ \·\\ \·\\ \·\\ b_{m-1}\end{array}\right]$

wherein,as can be seen from the decomposition results, each element of the matrix B contains only the private information of two neighboring anchor nodes.

S33, the intermediate item A^TA carries out clustering decomposition

Since the intermediate term A is directly calculated^TA needs to acquire the positions of all anchor nodes, and the position information belongs to the privacy information of each anchor node. Therefore, the intermediate items are decomposed by using the decomposition result of the matrix A, so that the privacy information can be simply and safely calculated in the decomposed result. In particular, decomposition according to matrix AAs a result, for A^TA carries on the clustering and decomposes, can find the vector product only contains the privacy information of a single anchor node in the first kind of the result after decomposing, the vector product only contains the privacy information of the adjacent anchor node in the second kind, namely:

A^TA＝V₁-V₂

wherein,as can be seen from the decomposition results, the intermediate term A is computed for security^TA, for V₁Only privacy preserving sum calculation is needed for V₂Only privacy protection for adjacent product sum calculations is required.

S34, the intermediate item A^TB performing clustering decomposition

Since the intermediate term A is directly calculated^TB, acquiring the position information of all anchor nodes and the ranging information between the anchor nodes and the target node, wherein the position information and the ranging information are privacy information of the anchor nodes. Therefore, the intermediate items need to be decomposed by using the decomposition results of the matrix a and the matrix B, so that the decomposed results can be used for simply and safely calculating the private information. Specifically, according to the decomposition results of the matrixes A and B, the matrix A is subjected to^TB, clustering decomposition is carried out, so that the decomposed vector product in the first class only contains the privacy information of a single anchor node, and the vector product in the second class only contains the privacy information of adjacent anchor nodes, namely:

A^TB＝U₁-U₂

wherein,as can be seen from the decomposition results, the intermediate term A is computed for security^TB, for U₁Only privacy protection summation calculation is needed for U₂Only privacy protection for adjacent product sum calculations is required.

S4, carrying out privacy protection summation calculation and privacy protection adjacent product solving and calculation

S41, privacy protection summation calculation

According to the pair of the intermediate item A^TA and A^TB, two results can be found, a first type V₁And U₁Medium vector product computation containing information for a single anchor node, e.g.Andonly the information of the anchor node i is contained,andonly the information of anchor node i +1 is contained. V can thus be calculated using a privacy preserving summation method₁And U₁. Specifically, for the intermediate item A^TA decomposition results of the first kindAndintermediate item A^TB decomposition results first classAnda privacy preserving summation calculation is performed.

The privacy protection summation calculation needs to be carried out on the privacy information of m-1 anchor nodes, and the summation calculation is carried outThe privacy information of each anchor node is protected in the process, and the summation result is only known by the target node. Specifically, assume target node 0, anchor node i, and anchor node privacy information M_i(i-1, …, m-1), privacy preserving computing is requiredThe privacy preserving sum calculation process is as follows: the anchor node i (i-1, …, m-1) generates (m-1) random matricesk＝1,…,m-1，Anchor node i reservationTransmitting the remaining matrices to corresponding (m-2) nodes; the anchor node i adds the received matrix sent by other nodes with the reserved matrix to construct a matrixWhere P is_iIs a random matrix, andanchor node i send α_i＝M_i+P_iTo target node 0; based on the received information, target node 0 calculatesHere α is the result of the privacy preserving sum computation the flow chart of the privacy preserving sum computation is shown in fig. 2.

S42, carrying out adjacent product calculation and calculation under privacy protection

According to the pair of the intermediate item A^TA and A^TB, the second of the two results can be foundClass V₂And U₂The vector products each contain information about two neighboring anchor nodes, e.g.Andboth contain information for anchor node i and anchor node i + 1. Therefore, V can be summed up by using the method of privacy protection₂And U₂And (6) performing calculation. Specifically, for the intermediate item A^TA decomposition results in the second classAndand the intermediate item A^TB decomposition results in the second classAndthe adjacent product sum calculation is performed with privacy protection.

The adjacent product and calculation for privacy protection needs to perform product calculation on the privacy information of two adjacent anchor nodes in the m anchor nodes, and then perform summation calculation. And the privacy information of each anchor node is protected in the calculation process, and the calculation result is only known by the target node. Specifically, assume target node 0, anchor node i, and anchor node privacy information M_i(i-1, …, m-1), privacy preserving computing is requiredThe calculation process of the adjacent product sum by privacy protection is as follows: anchor node i (i-1, …, m-1) generationWill be provided withIs reserved, willSending the random number to a node i +1, and receiving the random number sent by the anchor node i +1 by the anchor node iConstructing random numbersAnchor node i +1 generationWill be provided withIs reserved, willSending the random number to a node i, and receiving the random number sent by the anchor node i +1Constructing random numbersAnchor node i sendTo target node 0; anchor node i +1 transmissionTo target node 0, target node 0 calculates β based on the received information_i,i+1＝β_iβ_i+1β obtained by calculation_i,i+1(i-1, …, m-1), target node 0 calculationHere β is the result of the neighbor product sum calculation for privacy protection.a flow chart for neighbor product sum for privacy protection is shown in fig. 3.

S5, utilizing A^TA and A^TB, privacy protection calculation result and target node carry out position calculation

For position calculation, the intermediate term A needs to be acquired^TA and A^TAnd B, calculating results. If the calculation is performed directly, it is necessary to know the location information and ranging information of all anchor nodes, which may result in privacy leakage. In order to solve the problem, a method of calculating the adjacent product sum by privacy protection summation and privacy protection is adopted to carry out the intermediate term A^TA and A^TAnd B, carrying out privacy protection calculation. Suppose for the intermediate term A^TA and the intermediate term A^TB is recorded as omega and psi, the position of the target node isSpecifically, for the intermediate item A^TV of A decomposition result₁The calculation results of the two items in the group for privacy protection summation are respectively recorded asFor the intermediate item A^TU of B decomposition result₁The calculation results of the two items in the group for privacy protection summation are respectively recorded asFor the intermediate item A^TV of A decomposition result₂The two calculation results of the adjacent product sum under privacy protection are respectively recorded asFor the intermediate item A^TU of B decomposition result₂The two calculation results of the adjacent product sum under privacy protection are respectively recorded asThen the target node 0 calculates Ω - Ω₁+Ω₂-Ω₃-Ω₄，ψ＝ψ₁+ψ₂-ψ₃-ψ₄，Here, theFor the position calculation result of the target node, Ω is the intermediate term A^TThe calculation result of A, psi, is the intermediate term A^TAnd B, calculating results. The following are simulation experiment results:

the simulation experiment parameters are configured as follows: assume that each transferred element is represented by 24 bits. KexX₁,χ₂,₁,₂Respectively representing the time for executing 24-bit multiplication operation, 2048-bit multiplication operation, 1024-bit exponential operation and 2048-bit exponential operation. In the numerical analysis herein, χ is assumed₁＝1μs,χ₂＝0.88ms,₁＝81.08ms,₂159.06 ms. Assume that the communication bandwidth is 2 Mbps. In the experiment, the calculation cost, the communication cost and the execution time of the efficient privacy protection method for the anchor node ranging and positioning are analyzed. The computation cost mainly measures the CPU time used for computing the vector product, and the communication cost mainly measures the number of bits transmitted by the positioning participants. The algorithm execution time is defined as: the time consumed by each step of the algorithm comprises calculation and communication cost, and the steps executed by a plurality of nodes in parallel are only calculated once. Here, only the results of two-dimensional localization were analyzed, and the results of three-dimensional localization were similar.

Fig. 4 shows the analysis results of the calculation cost of the whole privacy protection method, the calculation cost of a single anchor node, and the calculation cost of a target node. Firstly, the calculation cost of the whole method and the calculation cost of the target node are increased along with the increase of the number m of the anchor nodes, and the reason is that more anchor nodes participate in positioning along with the increase of the number of the anchor nodes, and the target node needs to perform more calculations, so the calculation cost of the whole method and the calculation cost of the target node are increased. Secondly, it can be found that the calculation cost of a single anchor node is kept unchanged along with the increase of the number of the anchor nodes, because the calculation cost of the anchor node is irrelevant to the number of the anchor nodes in the efficient privacy protection method for performing the anchor node ranging and positioning. Finally, it can be found that the computation cost of the whole method of the present invention is higher than that of the target node, because the computation cost of the whole method includes the computation costs of all anchor nodes and the computation cost of the target node. Fig. 5 shows the communication cost, the communication cost of a single anchor node and the communication cost analysis result of a target node in the whole method. Firstly, it can be seen that as the number of anchor nodes increases, the communication cost of the whole method, the communication cost of a single anchor node and the communication cost of a target node increase, because as the number of anchor nodes increases, more anchor nodes participate in positioning, and more communication bits are transmitted. Secondly, it can be seen that the communication cost of the whole method is greater than that of the target node and a single anchor node, because the communication cost of the whole method includes the communication costs of all the anchor nodes and the communication cost of the target node. Finally, it can be seen that the communication cost of the target node is higher than that of a single anchor node, because in the efficient privacy protection method for anchor node ranging and positioning of the present invention, the target node needs to communicate with all anchor nodes, and the single anchor node only needs to communicate with the target node and the adjacent anchor nodes.

FIG. 6 shows the results of the analysis of the overall method execution time, the execution time of a single anchor node, and the execution time of a target node. First, it can be seen that as the number of anchor nodes increases, the overall method execution time, the single anchor node execution time, and the target node execution time all increase, because as the number of anchor nodes increases, more anchor nodes participate in positioning and more computation and communication will be performed. Secondly, the target node execution time can be found to be consistent with the whole method execution time. Through analysis, the efficient privacy protection method for anchor node ranging and positioning disclosed by the invention is found that most of the calculation process and communication cost are located in the target node, and the anchor node only needs to perform a small part of calculation and communication, so that the completion of the execution of the target node means the completion of the execution of the whole method. Finally, it can be seen that the execution time of a single anchor node is smaller than the target node execution time, since the target node performs more computation and communication tasks.

In summary, the efficient privacy protection method for anchor node ranging and positioning of the present invention does not need to use a homomorphic encryption algorithm, can protect the privacy information of all users in the anchor point ranging and positioning process, and has relatively low computation cost and communication cost.

It should be noted that any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and that the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may be executed out of order from that shown or discussed, including substantially the same way or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of patentable embodiments.

In the description herein, references to the terms "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and not to be construed as limiting the invention, and that those skilled in the art can make changes, modifications, substitutions and alterations to the above embodiments without departing from the spirit and scope of the invention.

Claims (8)

1. An efficient privacy protection method for anchor node ranging and positioning is characterized by comprising the following steps:

s1, an anchor node executes a ranging process from the anchor node to a target node to obtain a ranging information set D;

s2, constructing a coefficient matrix A and a ranging matrix B according to anchor node position information and the ranging information set D;

s3, performing line-by-line decomposition on the matrix A and the matrix B respectively, and performing line-by-line decomposition on the intermediate item A^TA and the intermediate term A^TB, performing clustering decomposition;

s4, carrying out privacy protection summation calculation and privacy protection adjacent product summation calculation aiming at the intermediate item decomposition result;

s5, utilizing A^TA and A^TAnd B, performing privacy protection calculation, and performing position calculation on the target node.

2. The method for efficient privacy protection for anchor node ranging and positioning as claimed in claim 1, wherein in S1, assuming that there are m anchor nodes in a region, i-1, …, m, d for anchor nodes_i0Representing an estimate of the distance of the anchor node i to the target node 0, i.e. ranging information d_i0Obtaining a ranging information set D ═ D after the ranging phase is finished for the privacy information of the anchor node i_i0,i＝1…m}。

3. The method for efficient privacy protection for anchor node ranging and positioning as claimed in claim 1, wherein the S2 is configured by the following process of coefficient matrix a and ranging matrix B:

s21, constructing a coefficient matrix A, and assuming the position of an anchor node iWhere n represents a dimension of space, the matrix a is defined as:

s22, constructing a ranging matrix B, wherein the definition of the matrix B is as follows according to the ranging information set D and the position coordinate information:

$B\stackrel{def}{=}\left[\begin{array}{c}{\mathrm{\Σ}}_{j=1}^n\left(x_{1j}^2-x_{2j}^2\right)-\left(d_{10}^2-d_{20}^2\right)\\ {\mathrm{\Σ}}_{j=1}^n\left(x_{2j}^2-x_{3j}^2\right)-\left(d_{20}^2-d_{30}^2\right)\\ \begin{array}{c}.\\ .\\ .\end{array}\\ {\mathrm{\Σ}}_{j=1}^n\left(x_{m-1j}^2-x_{mj}^2\right)-\left(d_{m-10}^2-d_{m0}^2\right)\end{array}\right].$

4. the method for efficient privacy protection for anchor node ranging and positioning as claimed in claim 1, wherein said S3 specifically comprises:

s31, decomposing each row of the matrix A, namely:

$A=\left[\begin{array}{c}{A}_1\\ \begin{array}{c}.\\ .\\ .\end{array}\\ A_{m-1}\end{array}\right]$

wherein A is_i＝2[x_i1-x_i+11…x_in-x_i+1n]＝2(x_i-x_i+1),i＝1,…,m-1；

S32, decomposing each row of the matrix B, namely:

$B=\left[\begin{array}{c}{b}_1\\ \begin{array}{c}.\\ .\\ .\end{array}\\ b_{m-1}\end{array}\right]$

wherein,

s33, the intermediate item A^TA clustering decomposition, according to the decomposition result of matrix A, for A^TA is decomposed so that the vectors in the first class of the decomposed result are multipliedThe product contains only the privacy information of a single anchor node, and the vector product in the second class contains only the privacy information of neighboring anchor nodes, i.e.:

A^TA＝V₁-V₂

wherein,

s34, the intermediate item A^TB clustering decomposition, according to the decomposition results of the matrixes A and B, carrying out A clustering decomposition on the matrixes^TB, decomposing is carried out, so that the decomposed vector product in the first class only contains the privacy information of a single anchor node, and the vector product in the second class only contains the privacy information of adjacent anchor nodes, namely:

A^TB＝U₁-U₂

wherein,

5. the method for efficient privacy protection for anchor node ranging positioning as claimed in claim 1 wherein said S4 further comprises:

s41, the intermediate item A^TV of A decomposition result₁Performing privacy protection summation calculation on the intermediate item A^TU of B decomposition result₁Carrying out privacy protection summation calculation;

s42, the intermediate item A^TV of A decomposition result₂Performing privacy protection on the adjacent product sum calculation, and performing intermediate term A^TU of B decomposition result₂And carrying out privacy protection adjacent product summation calculation.

6. The method for efficient privacy protection for anchor node ranging positioning as claimed in claim 1 or 5 wherein said privacy protection sum computation comprises: suppose M_i(i-1, …, m-1) is the privacy information at anchor node i, then the privacy-preserving sum, i.e. privacy-preserving computationThe anchor node i (i-1, …, m-1) generates (m-1) random matricesk＝1,…,m-1，Anchor node i reservationThe rest matrixes are sent to corresponding (m-2) nodes, and the anchor node i adds the matrixes received by the anchor node i and sent by other nodes with the reserved matrixes to construct a matrixWhere P is_iIs a random matrix, andanchor node i send α_i＝M₁+P_iTo the target node 0, the target node 0 calculates according to the received informationHere α is the result of the privacy preserving sum computation.

7. The method for efficient privacy protection for anchor node ranging positioning as claimed in claim 1 or 5 wherein said privacy protection neighbor product sum computation comprises: suppose M_i(i-1, …, m-1) is privacy information at anchor node i, and the privacy protection is a sum of adjacent products, i.e. privacy protection calculationAnchor node i (i-1, …, m-1) generationWill be provided withIs reserved, willSending the random number to a node i +1, and receiving the random number sent by the anchor node i +1 by the anchor node iConstructing random numbersAnchor node i +1 generationWill be provided withIs reserved, willSending the random number to a node i, and receiving the random number sent by the anchor node i +1Constructing random numbersAnchor node i sendTo target node 0, anchor node i +1 sendsTo the target node 0, the target node 0 calculates according to the received informationβ_i,i+1＝β_iβ_i+1β obtained by calculation_i,i+1(i-1, …, m-1), target node 0 calculationHere β is the result of the neighbor product sum computation for privacy protection.

8. The method for efficient privacy protection for anchor node ranging positioning as claimed in claim 1 wherein said S5 comprises: intermediate item A using sum of privacy protection calculation and sum of adjacent products calculation of privacy protection^TA and the intermediate term A^TB, carrying out privacy protection calculation, and assuming that calculation results are respectively omega and psi, the position of the target node is