CN111159733A

CN111159733A - Vector signature method with anti-acquisition function

Info

Publication number: CN111159733A
Application number: CN201911299010.9A
Authority: CN
Inventors: 康利生; 王磊; 李朝鹏; 王涛; 李大光; 邢晓桐
Original assignee: Bohai Shipyard Group Co Ltd
Current assignee: Bohai Shipyard Group Co Ltd
Priority date: 2019-12-17
Filing date: 2019-12-17
Publication date: 2020-05-15

Abstract

A method of vector signature with anti-acquisition functionality. The signature making comprises: user signature collection, signature making and vector data conversion. The signature inserting step includes extracting signature data, parsing into vector data, and generating a vector graphic code of a corresponding document. The signature data is not stored in the document in the form of a single picture resource any more, and the signature picture is difficult to acquire in a simple mode. Thereby performing the function of protecting the signature from being acquired. The method is suitable for signature anti-theft method application.

Description

Vector signature method with anti-acquisition function

Technical Field

The invention relates to a vector signature technology with an anti-acquisition function, which can increase the difficulty of acquiring a user signature and belongs to a vector signature method with the anti-acquisition function in the technical field of office automation in a computer data processing system.

Background

With the rapid development and popularization of networking and intellectualization, more and more services can be handled through networking, and signatures are inevitably required in the services. And if the signature is the online signature, acquiring the signature of the user as a dot matrix or a vector picture, inserting the picture into a document PDF or XPS document, and if the signature is not the online signature, reading the prepared signature picture of the user, and inserting the picture into the document.

Whether the user writes by hand on line or inserts the existing signature file into an internal system, the signature of the end user is embedded into the document for viewing, so that the signature can be acquired by a person who looks up the document, and the signature can be used for other purposes, and certain potential safety hazards exist. The most common electronic document formats at present are Adobe PDF and microsoft XPS, both documents belong to non-editable electronic documents, but in any format, the signature is stored in the document in a picture format, and the picture is stored in a resource folder in the document, so that the original data can be easily acquired. For example, a user signed picture is inserted into Word and then saved as a file in PDF format and XPS format, respectively. If the PDF file is saved in html format, we can see the inserted signature file in the images folder of the saving position. The XPS file is decompressed, and the inserted signature file can be seen in a \ Resources \ Images folder at the decompression position.

Besides, a picture signed by the user can be obtained through a capture mode, and if the original file is also a non-vector picture, the non-vector picture obtained through capture can be false and spurious to a certain extent.

In order to solve the problem that the user signature is acquired in the above-described case, the following problems need to be solved:

1. the picture source file in the electronic document can not be acquired by others through simple means.

2. The signature should use vector graphics to make the picture captured through the screen much different from the real original file.

Disclosure of Invention

Aiming at the problem that a traditional method is easy to acquire a signature picture, the invention provides a method for preventing a vector signature of an acquisition function. The method decomposes and converts vector graphics into original description data as a signature file, converts the signature data into corresponding vector graphics to be inserted into a document through a program when the signature is inserted, and one signature can be dispersedly inserted into the document by tens or hundreds of vector graphics, and the data cannot be reversely extracted from the document to be combined into a signature picture, so that the acquisition prevention function is realized, and the technical problem of vector signature theft prevention is solved.

The technical scheme adopted by the invention for solving the technical problem is as follows:

(1) and (3) signature preparation:

the step aims at the condition that a signature file needs to be made in advance according to the user signature picture. The signature file can be stored on the user computer, in the USBKEY or in the server, and can be extracted and inserted into the specified document when needed.

1) User signature collection:

the user signature may be obtained by signing on paper and then scanning into picture format of JPG, PNG, BMP, etc. The picture format supported by the integrated system can also be directly adopted by the handwriting board.

2) Processing into a vector diagram:

the dot matrix format pictures such as JPG, PNG, BMP and the like are processed into vector graphics such as EMF or WMF by using vector graphics design software such as Adobe illustrator, CoreDRAW and the like, and the processing aims to only keep the handwriting graphics, and the background is completely removed. Preprocessing can be performed by using Photoshop to facilitate vector graphics software processing.

If the user signature capture is directly captured as a vector graphic in EMF or WMF format, this step is skipped.

3) Converting vector data:

the purpose of this step is to decompose the vector graphics into a plurality of completely independent graphics description data. And extracting the elements forming the vector diagram, and describing data of points, lines, rectangles, polygons and circles from the vector diagram, and storing the describing data in an XML format or other user-defined formats. The data can be extracted by self-writing programs according to EMF or WMF file formats, and other software with the function can be used for extracting the data.

Vector data of the EMF or WMF file is extracted and stored into an XML file or a file format defined by a user, and document storage is realized by adding data.

The vector graphics are converted into vector data such as a straight line, a curve and the like.

4) Generating a signature file, encrypting:

the converted vector data is generated into a signature file, and encryption, compression and the like can be used to improve the security of the signature file and reduce the file.

(2) Signature insertion document:

1.1 extracting signature data:

A. if an online signature mode is used, the content input by a user through a handwriting pad, direct screen handwriting and the like is collected into vector graphics or other data which can be used for vector conversion.

B. And loading the user signature file which is manufactured in advance, and decrypting/decompressing the user signature file.

2.1 resolution into vector data:

and converting the user signature data acquired in the last step into vector data.

3.1 generating vector graphics code of the corresponding document and inserting:

the vector data is inserted after generating a description data block for the document according to a different document format (PDF or XPS), calculating a position to be deviated in the page, and setting a coordinate position.

The positive effects are as follows: the signature data is not stored in the document in the form of a single picture resource any more, and the signature picture is difficult to acquire in a simple mode. Because the vector graphics are used, the vector graphics cannot be distorted when being amplified and reduced, and even if the signature file can be acquired by using a screen capture mode, the display and printing effects of the vector graphics are not achieved. For PDF documents, no more signed pictures are saved to the images folder by save. For the XPS document, no signed picture resource exists under the Resources path, and by looking up the description data of the XPS document, the signature data and normal document data are described by using Xaml codes and cannot be distinguished, so that the function of protecting the signature from being acquired is achieved. The method is suitable for signature anti-theft method application.

Drawings

Fig. 1 is a flow chart of a conventional signature method according to the present invention.

Detailed Description

And after the user signature is started, acquiring the user signature, analyzing whether the user signature is a vector diagram or not, converting the user signature into the vector diagram if the user signature is not the vector diagram, converting the vector diagram into vector data, generating a signature file according to the vector data, and then finishing.

The specific implementation steps are as follows:

(1) and (3) signature preparation:

1) User signature collection:

2) Processing into a vector diagram:

3) Converting vector data:

4) Generating a signature file, encrypting:

(2) Signature insertion document:

1.1 extracting signature data:

2.1 resolution into vector data:

Example data in XPS certain page insertion (3) method such as using C #:

///<summary>

v/insert decomposed signature data into specified locations of the page

///</summary>

// < param name = "page" > Page in XPS >

// < param name = "x" > sign x coordinate to place >

// < param name = "y" > sign y coordinate to place >

// < param name = "width" > signature width >

// < param name = "height" > signature height >

// < param name = "data" > signature vector data (string format) </param >

private void InserSign(FixedPage page, double x, double y,doublewidth,double height, string data)

{

Canvas cvs = XamlReader.Parse(data) as Canvas;

Viewbox vb = new Viewbox();

vb.Child = cvs;

vb.Width = width;

vb.Height = height;

page.Children.Add(vb);

}

If the picture is inserted directly, the data saved in XPS is as follows:

the signature picture can be stored in the XPS resource folder and can be extracted, and even can be directly copied and pasted in the XPS Viewer.

While, using the above-mentioned method, the signed data is in the following state (partial data) in XPS:

……

if the positions of the stroke data are intentionally confused at the time of insertion and are dispersedly inserted in the document, it is almost impossible to obtain the restoration.

The method is characterized in that:

the application of the technology of the invention can prevent the vector signature from being stolen, thereby improving the anti-theft function of the electronic signature and enabling the vector data to be stable and safe.

Claims

1. A method for vector signature with anti-acquisition function is characterized in that: the specific implementation steps are as follows:

(1) and (3) signature preparation:

aiming at the situation that a signature file needs to be made in advance according to a user signature picture; the signature file can be stored on a user computer, in a USBKEY or in a server, and can be extracted and inserted into a specified document when needed;

1) user signature collection:

the user signature can be signed on paper and then scanned into picture formats such as JPG, PNG, BMP and the like; the picture format supported by the integrated system can also be directly adopted by the handwriting board;

2) processing into a vector diagram:

processing dot matrix format pictures such as JPG, PNG, BMP and the like into vector graphics such as EMF or WMF by using vector graphics design software such as Adobe illustrator, CoreDRAW and the like, wherein the processing aims to only retain the handwriting graphics, and the background is completely removed; photoshop can be utilized for preprocessing, so that vector graphics software processing is more convenient;

if the user signature is directly acquired as a vector graph in EMF or WMF format, the step is skipped;

3) converting vector data:

the purpose of this step is to decompose the vector graphics into a plurality of completely independent graphics description data; extracting elements forming the vector diagram from the vector diagram, and describing data of points, lines, rectangles, polygons and circles, and storing the describing data in an XML format or other user-defined formats; the data can be extracted by self-writing programs according to EMF or WMF file formats, and other software with the function can be used for extracting the data;

vector data of the EMF or WMF file is extracted and stored into an XML file or a file format defined by a user, and document storage is realized by adding data;

the vector graphics are converted into vector data such as a straight line, a curve and the like;

4) generating a signature file, encrypting:

generating the converted vector data into a signature file, and using encryption, compression and other operations to improve the security of the signature file and reduce the file;

(2) signature insertion document:

1.1) extracting signature data:

A. if an online signature mode is used, acquiring the content input by a user through a handwriting board, direct screen handwriting and the like into vector graphics or other data which can be used for vector conversion;

B. loading a user signature file which is manufactured in advance, and decrypting/decompressing the user signature file;

2.1) parsing into vector data:

converting the user signature data acquired in the last step into vector data;

3.1) generating vector graphic codes of corresponding documents and inserting:

generating a description data block for the document according to different document formats PDF or XPS by the vector data, calculating a position to be deviated in a page, setting a coordinate position and inserting the coordinate position.