A method and system for encrypting printed information

Abstract

A printing information encryption method and system, wherein the method comprises an encryption step, the encryption step comprising: intercepting a printing task, obtaining a to-be-printed page, obtaining the height H of the printing page, and dividing the edge outside the content in the printing page into N marking blocks with a height of H / N along the height or width, generating M random integers {R1, R2, R3...Rm} with an interval of [0, N) as a trace code, sequentially taking the trace codes from the trace code set, setting the i-th micro dot in the R1-th marking block, and obtaining an encrypted page until all micro dot markings are completed. Through the above scheme, the printing page can be encoded, and the encrypted page is obtained by adding the pixel points, thereby improving the encryption of the printed document. The above scheme is also easy to restore and decode, and can also be applied to the trace work of the printed document.

Claims

1. A method of encrypting printed information, characterized by, Including encryption steps, The encryption steps include: Intercept the print job and obtain the page to be printed. The height H of the printed page is defined, and the edges outside the content of the printed page are divided into N marked blocks of height H / N along either the height or width. Generate M random integers {R1, R2, R3, ..., Rm} within the interval [0, N) to serve as the source code. The trace code is taken out sequentially from the trace code set, and the i-th micro point is set in the Ri-th marked block until all micro points are marked, thus obtaining the encrypted page; When decoding is required, the following steps are performed: image analysis is performed on the encrypted page marked with tiny dots, all connected graphs in the encrypted page are filtered out, and connected graphs whose perimeter and aspect ratio do not meet the preset conditions are filtered out to obtain the filtering results; In the filtering results, the location information of the tiny point is obtained, the content height of the encrypted page is obtained, the specific number of the marker block in the N equally divided marker blocks of the content height of the encrypted page is determined, and the source code corresponding to the tiny point is restored. Find all connected graphs in the image to generate a preliminary set of tiny points. In this set, determine the starting point (X0, Ymin) and ending point (Xend, Ymax) by comparing their ordinates. Based on the principle of collinearity, define a virtual straight line called the standard line. Denote the distance between the starting and ending points as L, and divide it into N equal parts with a step size of Step = L / N. Sequentially extract the coordinates of the tiny points, denoted as (Xi, Yi). Then, the traceability code corresponding to the i-th standard tiny point is... , This indicates rounding down to the nearest integer.

2. The method for encrypting printed information according to claim 1, characterized in that, It also includes the step of binding the traceability code with the document information corresponding to the printing task.

3. The method for encrypting printed information according to claim 1, characterized in that, It also includes the step of marking a tiny dot at the beginning and end of the marked block.

4. The method for encrypting printed information according to claim 1, characterized in that, The encryption step further includes marking a tiny dot at the beginning and end of the marked block. When decoding is required, the smallest points with the largest and smallest coordinate values ​​are selected from the filtering results as the first and last smallest points, thereby determining the content height H.

5. A method for encrypting printed information according to claim 4, characterized in that, The standard line is determined by the first and last tiny points.

6. The method for encrypting printed information according to claim 1, characterized in that, The i-th micro-dot is positioned in the middle of the i-th marked block.

7. A printed information encryption system, characterized in that, This includes a cloud server and a printing terminal. When the cloud server detects a print job, it intercepts the print job and obtains the page to be printed. The height H of the printed page is defined, and the edges outside the content of the printed page are divided into N marked blocks of height H / N along either the height or width. Generate M random integers {R1, R2, R3, ..., Rm} within the interval [0, N) to serve as the source code. The trace code is taken out sequentially from the trace code set, and the i-th micro point is set in the Ri-th marked block until all micro points are marked, thus obtaining the encrypted page; Image parsing is performed on the encrypted page with tiny dot markings. All connected graphs in the encrypted page are filtered out, and connected graphs whose perimeter and aspect ratio do not meet the preset conditions are filtered out to obtain the filtering results. In the filtering results, the location information of the tiny point is obtained, the content height of the encrypted page is obtained, the specific number of the marker block in the N equally divided marker blocks of the content height of the encrypted page is determined, and the source code corresponding to the tiny point is restored. Find all connected graphs in the image to generate a preliminary set of tiny points. In this set, determine the starting point (X0, Ymin) and ending point (Xend, Ymax) by comparing their ordinates. Based on the principle of collinearity, define a virtual straight line called the standard line. Denote the distance between the starting and ending points as L, and divide it into N equal parts with a step size of Step = L / N. Sequentially extract the coordinates of the tiny points, denoted as (Xi, Yi). Then, the traceability code corresponding to the i-th standard tiny point is... , This indicates rounding down to the nearest integer.

8. A print information encryption system according to claim 7, characterized in that, The traceability code is bound to the document information corresponding to the printing task, and a tiny dot is marked at the beginning and end of the marked block.

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