CN102332079A - GIS Vector Data Camouflage and Restoration Method Based on Error Random Interference - Google Patents

Abstract

The invention discloses a method for disguising and restoring GIS vector data based on error random interference, which belongs to the field of geographic information security. The data masquerading processing steps of this method mainly include: (1) Open a GIS vector data layer file, determine the layer type and calculate the number of digits N after the decimal point in the abscissa data, and set 8-bit binary random information as the key Key , and stored in the key file; (2) Data reading and grouping; (3) For each group D _i in the array queue D, perform data error interference processing; (4) Cycle steps (2) (3) , until each element is processed, save the camouflaged data file. The method of the invention can effectively improve the security of GIS vector data in data transmission and decryption processing, and can be applied to hidden communication and safe transmission of GIS vector data.

Description

GIS Vector Data Camouflage and Restoration Method Based on Error Random Interference

technical field

The invention belongs to the field of geographic information security, and in particular relates to a method for disguising and restoring GIS vector data based on error random interference technology.

Background technique

The security protection of geographic information involves national security and social interests, and is a major national and social demand that needs to be urgently addressed. Especially in today's situation where the demand for spatial data sharing is gradually expanding and the application of geographic information services is expanding, the security issues of geographic information are further highlighted. As the main data content of the National Spatial Data Infrastructure, GIS vector data, its information security research is even more important.

At present, information camouflage has become another important branch besides cryptography in information security research. The analysis of relevant research literature and patent retrieval results at home and abroad shows that at present, in the research of information camouflage, the carrier data types mainly include images, videos, remote sensing images, DEM and so on. However, vector data has many characteristics such as data organization without fixed storage order, various data formats, powerful visual expression means, complex projection transformation, various spatial analysis applications, high precision and less redundancy. This makes the information camouflage research on vector data has certain particularity and great difficulty.

Contents of the invention

The object of the present invention is to propose a method for disguising and restoring GIS vector data based on error random interference technology, so as to effectively improve the security of GIS vector data in data transmission and decryption processing.

In order to achieve the above object, the technical solution adopted by the present invention mainly includes the following processes:

(1) Masquerade process

Step 1: Open a GIS vector data layer file, determine the layer type and calculate the number of digits N after the decimal point in the abscissa data, set 8-bit binary random information as the key Key, and store it in the key file;

Step 2: Data reading and grouping

，分为L组，组织到数组队列D中； (a) If it is line-surface type data, read the abscissa of all points in a feature each time, calculate the number m of points, and follow

, divided into L groups, organized into the array queue D;

(b) If it is point type data, read all the point elements in the file, calculate the number m of points, and set the abscissa of the relevant point elements according to , divided into L groups, organized into the array queue D;

Step 3: For each packet D _i in the array queue D, perform data error interference processing, the specific method is:

(a) Take the value d of the first decimal place of the first data D _i1 in the group D _i ;

(b) If 0<d<(N-1), exchange the d-th bit after the decimal point with the d+1-th bit of data for each data whose corresponding key information bit is 1 in the group;

  Step 4: Repeat steps 2 to 3 until each element is processed and save the camouflaged data file;

(2) Restoration process

Step 1: Open a GIS vector data layer file, determine the layer type and calculate the number of digits N after the decimal point in the abscissa data, read the key file and set the key Key;

Step 2: Read data in groups

,分为L组，组织到数组队列D中； (a) If it is line-surface type data, read the abscissa of all point coordinate data in an element each time, calculate its number m, and follow

, divided into L groups and organized into array queue D;

,分为L组，组织到数组队列D中； (b) If it is point type data, read all the point elements in the file, calculate the number m of points, and set the abscissa of the relevant point elements according to

, divided into L groups and organized into array queue D;

Step 3: For each coordinate group D _i , perform data restoration processing, the specific method is:

(a) Take the value d of the first decimal place of the first data D _i1 in the group D _i ;

(b) If 0<d<(N-1), exchange the d-th bit after the decimal point with the d+1-th bit of data for each data whose corresponding key information bit is 1 in the group;

Step 4: Repeat steps 2 to 3 until each element is processed, and then save the restored data file.

According to the data organization characteristics of GIS vector data and based on the error random interference principle, the present invention proposes a camouflage and restoration method for GIS vector data, which can perform camouflage and restoration processing of shp format data, and satisfies GIS vector data to a certain extent hidden communication and secure transmission requirements.

Description of drawings

Fig. 1 is the selected experimental data of the embodiment of the present invention.

Fig. 2 is a data masquerading flow chart of the method of the present invention.

Fig. 3 is a data restoration flow chart of the method of the present invention.

Fig. 4 is a local effect diagram of original data in the embodiment of the present invention.

Fig. 5 is a partial effect diagram of camouflaged data in the embodiment of the present invention.

Detailed ways

Further detailed description will be given below in conjunction with the accompanying drawings and embodiments.

In this example, a typical shp surface layer data is selected, and the whole process of data reading, camouflage processing, and data restoration is further described in detail. In this embodiment, the national 1:4 million provincial interface layer data (as shown in Figure 1) is selected as the experimental data. The value of the key Key is "10010101".

(1) Data masquerade processing.

Step 1: Open the provincial boundary layer data file, the data format is planar data, the number of data digits after the decimal point on the abscissa is 14, and the key key value is "10010101".

Step 2: Read the spatial data of each element in turn, calculate the number m of coordinate points in the currently processed element, and determine to perform grouping processing.

，分为56组。将每组数据写入数组d后并添加入数组队列D中。 The number of coordinate points of the first element read is 923. Since m>2n, according to

, divided into 56 groups. Write each set of data into array d and add it to array queue D.

Step 3: For each array D _i in the array queue D, perform data error interference processing. In this embodiment, the first data in the first array D ₁ is: 121.49738309820822, the value d of the first digit before the decimal point is 1, which meets the condition of 0<d<(N-1), then the corresponding For the four data such as 1, 4, 6, and 8 whose key information bit is 1, exchange the data of the first and second digits after the decimal point.

Step 4: Repeat steps 2 to 3 until each element is processed, and save the camouflaged data file.

(2) Data restoration processing.

Step 1: Open the provincial boundary layer data file after masquerading, and the data format is area data. Read the key file, and set the key Key, whose value is "10010101".

Step 2: Read the spatial data of each element in turn, calculate the number m of coordinate points in the currently processed element, and determine to perform grouping processing.

，分为56组。将每组数据写入数组d后并添加入数组队列D中。 The number of coordinate points of the first element read is 923. Since m>2n, according to

, divided into 56 groups. Write each set of data into array d and add it to array queue D.

Step 3: For each array D _i in the array queue D, perform data error interference processing. In this embodiment, the value d of the first digit before the decimal point of the first data in the first array D1 is 1, which meets the condition of 0<d<(N-1), then the corresponding key information bit in _the group is For the four data of 1, 1, 4, 6, and 8, exchange the data of the first digit and the second digit after the decimal point.

Step 4: Repeat steps 2 to 3 until each element is processed, and then save the restored data file.

In the embodiment of the present invention, only the abscissa of the surface layer data in shp format is used for data masquerade and restoration, and this method can also be applied to the data masquerade and restoration using the ordinate of the data.

In the embodiment of the present invention, only surface layer data is used for data camouflage and restoration processing, and this method can also be applied to point and line type layer data.

In the embodiment of the present invention, only the GIS vector data in shp format is used for data camouflage and restoration processing, and the method is also applicable to data camouflage and restoration processing of GIS vector data in other formats such as GML, E00, and MIF.

(3) Test analysis.

From the renderings of the original data and the masquerading data in the above embodiment (Fig. 4, Fig. 5), it can be seen that after the data is masquerading, although it is still the shp data that can be opened correctly by GIS software, the position of each coordinate point will be changed. For GIS vector data with high data accuracy and quality requirements, this process significantly reduces the data quality and data use value, limits the normal use of illegally copied or intercepted data, and achieves certain data protection purposes. Only when legitimate users obtain the key file can the data be restored correctly and losslessly.

In summary, the method adopted in the present invention can be successfully applied to the camouflage and restoration processing of GIS vector data, and satisfies the hidden communication and secure transmission requirements of GIS vector data to a certain extent.

Claims (1)

1. A method for camouflaging and restoring GIS vector data based on error random interference, including the following process: (1) Masquerade process Step 1: Open a GIS vector data layer file, determine the layer type and calculate the number of digits N after the decimal point in the abscissa data, set 8-bit binary random information as the key Key, and store it in the key file; Step 2: Data reading and grouping If it is line-surface type data, read the abscissa of all points in a feature each time, calculate the number m of points, and follow

, divided into L groups, organized into the array queue D; If it is point type data, read all the point elements in the file, calculate the number m of points, and set the abscissa of the relevant point elements according to , divided into L groups, organized into the array queue D; Step 3: For each packet D _i in the array queue D, perform data error interference processing, the specific method is: Take the value d of the first decimal place of the first data D _i1 in the group D _i ; If 0<d<(N-1), exchange the d-th bit after the decimal point with the d+1-th bit data for each data whose corresponding key information bit is 1 in the group; Step 4: Repeat steps 2 to 3 until each element is processed, and save the camouflaged data file; (2) Restoration process Step 1: Open a GIS vector data layer file, determine the layer type and calculate the number of digits N after the decimal point in the abscissa data, read the key file and set the key Key; Step 2: Read data in groups If it is line-surface type data, read the abscissa of all point coordinate data in an element each time, calculate its number m, and follow

, divided into L groups, organized into the array queue D; If it is point type data, read all the point elements in the file, calculate the number m of points, and set the abscissa of the relevant point elements according to

, divided into L groups, organized into the array queue D; Step 3: For each coordinate group D _i , perform data restoration processing, the specific method is: Take the value d of the first decimal place of the first data D _i1 in the group D _i ; If 0<d<(N-1), exchange the d-th bit after the decimal point with the d+1-th bit data for each data whose corresponding key information bit is 1 in the group; Step 4: Repeat steps 2 to 3 until each element is processed, and then save the restored data file.

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