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CN-122020715-A - Lightweight vector map compression encryption method and system

CN122020715ACN 122020715 ACN122020715 ACN 122020715ACN-122020715-A

Abstract

The invention provides a lightweight vector map compression encryption method and system, comprising the steps of extracting a multi-section line or polygon object from a vector map layer, identifying geometric key points by adopting an SDP algorithm, dividing coordinates into two types of key points and non-key points, and processing the two types of coordinates of the key points and the non-key points by adopting a differential processing strategy, wherein the non-key points are subjected to differential processing by adopting a delta coding algorithm to eliminate data redundancy, and the key points are processed by adopting a grid mapping method to realize coordinate conversion and reinforcement protection. The coordinate sequence is divided into a decimal sequence and an integer sequence, the integer sequence is compressed by adopting DRLE algorithm, exclusive-or encryption and scrambling are carried out, and positive integer conversion and scrambling are carried out on the decimal sequence. And finally, storing the processed coordinate sequence by adopting LCS and compressing the coordinate sequence by adopting LZMA2 algorithm to obtain the lossless compressed encryption map.

Inventors

  • XU YANYAN
  • LUO ZHIHUI

Assignees

  • 武汉大学

Dates

Publication Date
20260512
Application Date
20260129

Claims (10)

  1. 1. A lightweight vector map compression encryption method, comprising: Constructing a dynamic key generation scheme by fusing an SHA-512 hash algorithm and a unified chaotic system; Extracting a multi-section line or a polygonal object from a vector map layer to form a vector map coordinate sequence, identifying geometric key points of the vector map coordinate sequence by adopting a gradient-based Tagranse-Praeparata algorithm SDP algorithm, and dividing the vector map coordinate sequence into a key point coordinate sequence and a non-key point coordinate sequence; Converting the key point coordinate sequence by adopting a grid mapping method to protect coordinate information, and carrying out differential processing on the non-key point coordinate sequence by adopting a delta coding algorithm to eliminate data redundancy to obtain a processed coordinate sequence; dividing the processed coordinate sequence into an integer sequence and a small number sequence, compressing the integer sequence by adopting a directional run length coding DRLE algorithm, performing exclusive-or encryption and scrambling, performing positive integer conversion on the small number sequence, performing scrambling and scrambling, and performing encryption on a minimum boundary rectangle to obtain a compressed coordinate sequence; and storing the compressed coordinate sequence by using a lossless compression structure LCS to obtain an LCS structure, and compressing the LCS structure by using an LZMA2 algorithm to obtain a lossless compressed encryption map.
  2. 2. The lightweight vector map compression encryption method of claim 1, wherein constructing a dynamic key generation scheme by fusing a SHA-512 hash algorithm and a unified chaotic system comprises: Processing an initial key input by a user by adopting an SHA-512 hash algorithm to generate a first hash sequence; Processing a vector map layer with a preset format by adopting an SHA-512 hash algorithm to generate a second hash sequence; Performing exclusive OR operation on the first hash sequence and the second hash sequence to generate a third hash sequence; Normalizing the third hash sequence once according to each preset bit number to generate an initial value required by the unified chaotic system , , And real parameters ; And generating an encryption key by adopting the unified chaotic system: Wherein, the , , The system state variable represents the state of the system in a three-dimensional space, and changes with time to form a phase space track of the power system; Is a real parameter of the system when When the system is in a chaotic state; Generating a chaotic sequence , , Sum parameters , 。
  3. 3. The method of claim 1, wherein extracting a multi-segment line or a polygonal object from a vector map layer to form a vector map coordinate sequence, and identifying geometric key points of the vector map coordinate sequence by using an SDP algorithm comprises: Determining any vector map layer Comprising a plurality of multi-line segments or polygonal objects Each polygon object Comprising a plurality of vertexes , Representing objects The number of vertices to be included in the liquid crystal display device, Representing objects Key points screened in the process The sequence is composed of a sequence, Representing objects Non-key point composition sequence screened in the process , Comprising a plurality of key points Spaced apart sequence segments ; Default adding the first vertex and the last vertex into the key point sequence; The SDP algorithm is adopted to screen all other vertexes in sequence to obtain an object All keypoints and non-keypoints contained in (a) are described.
  4. 4. The method for compressing and encrypting a lightweight vector map according to claim 3, wherein the objects are obtained by sequentially screening the remaining vertices by SDP algorithm All the keypoints and non-keypoints contained in (a) include: Solving the vertex to be judged 、 And Slope between And : If it is determined that And (3) with If the absolute value of the difference is greater than the threshold value, then the vertex is determined Is a key point; if it is determined that And (3) with If the signs of the numbers are different, then the vertex is determined And judging the other conditions as non-key points if the key points are key points.
  5. 5. The lightweight vector map compression encryption method according to claim 1, characterized in that the converting the key point coordinate sequence by using a grid mapping method to protect coordinate information comprises: Determining any vector map layer Minimum bounding rectangle of (2) For the layer coordinate range, key points are determined Divided into integer parts And a fractional part ; Two floating point numbers generated by the unified chaotic system 、 Mapping into two integers 、 The minimum boundary rectangle Divided into Blocks forming a grid, respectively 、 Adding a first fixed value and a second fixed value to enable the grid number to be not less than the first fixed value multiplied by the second fixed value; With the grid sequence number of the key point Replacing integer parts of keypoint coordinates The decimal part of the key point Replaced by key point coordinates Lower left corner coordinates of grid where key points are located Is the difference between (1); From the following components Representing a sequence of keypoints The number of the key points is contained, and the new key points after replacement are as follows The new key point sequence after replacement is recorded as : 。
  6. 6. The lightweight vector map compression encryption method of claim 5, characterized in that the differential processing of the non-keypoint coordinate sequence using delta encoding algorithm to eliminate data redundancy comprises: For non-key point sequence segment between two key points Processing to obtain differential coordinate values Substitute for original coordinate values Obtaining non-key point differential sequence segments The differential process is as follows: Wherein, the Representing non-keypoints in sequence segments Is the number of (3); representing the number of sequence segments contained, all non-critical point differential sequence segments Composing non-keypoint differential sequences 。
  7. 7. The method for compressing and encrypting a lightweight vector map according to claim 5, wherein the dividing the processed coordinate sequence into an integer sequence and a small number sequence, compressing the integer sequence by DRLE algorithm, performing exclusive-or encryption and scrambling, performing positive integer conversion and scrambling on the small number sequence, and encrypting the minimum bounding rectangle to obtain the compressed coordinate sequence, comprises: the mapped key point coordinates and the non-key point coordinates after differential coding form a new coordinate sequence, and the object is constructed and obtained And objects are processed The coordinate sequence being divided into integer parts And a fractional part , wherein, And Representing objects respectively A kind of electronic device An integer portion and a fractional portion of the points; Adopts DRLE algorithm pairs Compressing the integer part of the object Conversion of integer parts of (a) into run-length code sections Each run-length code segment Critical run coordinates including identification direction And number of non-keypoints Wherein the key run coordinates correspond to the key points one by one, and the key run coordinates Is calculated as follows: In the formula, Representing the integer part of the coordinates of the key points after mapping, if the number of non-key points after the key points is zero, adopting the difference between two adjacent key points to replace As the judgment basis according to the key run coordinates The parity of the following differential encoding section is positive and negative; encrypting the integer part compressed by DRLE algorithm, and adopting a sequence generated by a unified chaotic system For key run coordinates Exclusive-or encryption is carried out, and the coordinates after encryption are obtained The following are provided: Sequence generated by unified chaotic system 、 For the number of non-key points Scrambling to generate a final integer part sequence ; Encrypting the decimal part of the coordinate sequence, and converting the decimal part of the coordinate into an integer: In the formula, Setting according to the distribution condition of the data to ensure that all decimal numbers are converted into integers and redundancy is not generated; Sequence generated by unified chaotic system Scrambling the fractional part of the sequence of coordinates, Generating small sequences of coordinates of similar size The process is as follows: In the formula, Setting according to the distribution condition of the data to ensure that the converted decimal cannot be distinguished; Sequence-based 、 Scrambling the decimal part sequence by adopting double reset scrambling to obtain a final decimal part sequence ; By using sequences For a pair of Is exclusive-or encrypted, the process is as follows: 。
  8. 8. The method for compressing and encrypting a lightweight vector map according to claim 1, wherein storing the compressed coordinate sequence with LCS to obtain an LCS structure, compressing the LCS structure with LZMA2 algorithm to obtain a lossless compressed encrypted map, comprises: sequentially storing each run code section of element type, MBR, element number and coordinate integer part of the layer by LCS Length of (c) and its code and coordinate fraction parts; and compressing the LCS data by adopting an LZMA2 algorithm, and outputting the encrypted map after lossless compression.
  9. 9. A lightweight vector map compression encryption system, comprising: The construction module is used for constructing a dynamic key generation scheme by fusing an SHA-512 hash algorithm and a unified chaotic system; The dividing module is used for extracting a multi-section line or a polygonal object from the vector map layer to form a vector map coordinate sequence, identifying geometric key points of the vector map coordinate sequence by adopting an SDP algorithm, and dividing the vector map coordinate sequence into a key point coordinate sequence and a non-key point coordinate sequence; The conversion module is used for carrying out conversion processing on the key point coordinate sequence by adopting a grid mapping method so as to protect coordinate information, and carrying out differential processing on the non-key point coordinate sequence by adopting a delta coding algorithm so as to eliminate data redundancy, so that a processed coordinate sequence is obtained; The compression module is used for dividing the processed coordinate sequence into an integer sequence and a small number sequence, compressing the integer sequence by adopting DRLE algorithm, performing exclusive-or encryption and scrambling, performing positive integer conversion on the small number sequence, performing scrambling and scrambling, and performing encryption on the minimum boundary rectangle to obtain the compressed coordinate sequence; and the output module is used for storing the compressed coordinate sequence by utilizing the LCS to obtain an LCS structure, and compressing the LCS structure by adopting an LZMA2 algorithm to obtain the lossless compressed encryption map.
  10. 10. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the lightweight vector map compression encryption method of any one of claims 1 to 8 when the program is executed.

Description

Lightweight vector map compression encryption method and system Technical Field The invention relates to the technical field of geographic information security, in particular to a lightweight vector map compression encryption method and system. Background The vector map is used as one of the core data types in the geographic information system, and by virtue of the capability of accurately expressing geographic entities, the vector map becomes an indispensable spatial information carrier in various fields such as military planning, socioeconomic analysis, traffic management, city planning, disaster emergency and the like. The high-precision coordinate information and rich attribute data not only support daily navigation and position service, but also relate to the overall management of homeland security, infrastructure layout and strategic resources. Therefore, the data security of the vector map is a basic guarantee for the healthy development of a security system and the geographic information industry. With the rapid development of the internet and mobile communication technology, network distribution has become a mainstream mode of vector map data exchange, sharing and service. However, the open environment also brings obvious potential safety hazards that sensitive information is revealed due to the fact that data can be intercepted in the transmission process, the data can be tampered maliciously to influence decision accuracy, and even the risks that ownership and commercial value of the data are damaged due to illegal copying and distribution exist. Against these challenges, passive protection means such as access control, rights management and watermarking technologies are not enough, and encryption technology is used as an active defense means and is increasingly a key technical path for protecting vector map contents. The existing vector map encryption technology is mainly divided into three types, namely an encryption method based on traditional cryptography, an encryption method based on a chaotic system and a selective encryption method. The first type of encryption method mainly adopts symmetric key encryption or asymmetric key encryption, and the method is easy to realize for integrally encrypting the map file, but cannot encrypt the content (such as a multi-section line, a polygon and the like) with fine granularity of the vector map, so that the encryption and decryption efficiency of the method is lower, and the method is particularly aimed at large-scale vector data. The second type of encryption method is based on a chaotic system to disturb the accurate position and morphological characteristics of a vector map object and destroy the inherent spatial relations of topology, measurement and the like. The encryption method based on the chaotic system can encrypt fine-grained contents of the vector map, but is difficult to resist statistical analysis attack, in addition, the low-dimensional chaotic system is degraded in dynamic characteristics due to limited word length of a computer, so that the safety is seriously affected, and the high-dimensional chaotic system is improved in safety, but is higher in calculation complexity, so that the encryption time of the vector map is increased in a straight line. The third type of encryption method has high encryption efficiency, but part of the methods are difficult to resist statistical attack, so that the security is poor. In summary, the existing vector map encryption method generally faces the problem that security and encryption efficiency are difficult to be compatible. More importantly, the vector map stores high-precision floating point coordinates, a single coordinate is stored by taking a double-precision floating point as an example, the adjacent coordinates of the vector map are usually close in position, the numerical difference is small, if each coordinate is still stored by using 16 bytes independently, the waste of storage space, namely the problem of data redundancy, is caused, the problem is mostly ignored in the conventional vector map encryption technology, original data is directly encrypted, the encrypted and transmitted object is still uncompressed relatively huge original data, encryption and transmission efficiency is greatly reduced, and therefore, the actual requirements of the limited scenes of computing resources and transmission resources such as automatic driving and terminals of the Internet of things are difficult to adapt. The compression is a common method for reducing the redundancy of vector map data, and can be divided into two types of lossy compression and lossless compression, wherein the lossy compression method cannot fully recover the original vector map information after decompression, so that the lossless compression is more suitable for being combined with an encryption process. However, since the coordinates stored in the vector map are of a floating point type and there are almost no duplicate coor