Risk assessment method for file transmission

Abstract

The invention relates to the technical field of file transmission, and discloses a risk assessment method for file transmission, which identifies and assesses possible risks by analyzing behavior characteristics of a user when the user browses a free part of an electronic file. The method comprises the following steps: firstly, acquiring risk duration of a free browsing part of an electronic file, and judging a browsing risk degree of a user according to the risk duration; for an electronic file with risks, a system marks keywords in the electronic file, and calculates an overall shielding area through a circumference intersection set formed by characters, so that effective protection of sensitive information is ensured. In addition, according to the method, by analyzing point location distribution on a browsing interface, a to-be-shielded area is screened through geometric calculation, and proper expansion is carried out, so that the shielding effect is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of file transmission, and in particular to a risk assessment method for file transmission. Background Art

[0002] In the current information age, electronic files have become the main carrier of knowledge and are widely used in many fields such as e-books, online document management, and enterprise data sharing. However, the resulting information security issues have also become increasingly prominent, especially in the process of file transmission, unauthorized content access, information leakage and other issues need to be solved urgently. In recent years, some intelligent detection technologies have begun to be applied to the field of file security management, such as risk assessment methods based on user behavior analysis. This type of method mainly relies on data such as user operation tracks and length of stay to make risk judgments. However, traditional protection methods mainly rely on static keyword filtering or permission control, which has two major defects: first, it is impossible to dynamically identify abnormal user browsing behavior; second, some important content is still left after the shielding is executed.

[0003] In summary, there is an urgent need for a risk assessment method for file transfer that can accurately identify users' risky behaviors and effectively shield sensitive content. Summary of the invention

[0004] The present invention provides a risk assessment method for file transmission, which helps solve the problems mentioned in the above background technology.

[0005] The present invention provides the following technical solution: a risk assessment method for file transmission, comprising: The duration of the risk of obtaining a free viewing portion of each electronic file; Determine the risk level of users browsing electronic files based on the risk duration; Mark keywords in risky electronic files; Obtain the intersection set of circles corresponding to the constituent characters of each marked keyword; Get the area to be shielded, specifically: Get the circumference of the intersection set that needs to be shielded as a whole; For a circle of an intersecting set that needs to be shielded as a whole, obtain the point of the center of each circle in the intersecting set of this circle, and record them as the first point, the second point...the Ath point, where A is equal to the number of groups in this circle; Choose any two points from the first point, the second point, ... point A, and draw a straight line passing through the two selected points; Determine whether other points on the browsing interface are on the same side of the drawn line, specifically: The straight line divides the browsing interface into two areas, which are respectively recorded as the first area and the second area; Get the number of other points in each area. If the number of other points in a certain area is 0, it is considered that other points on the browsing interface are on the same side of the straight line. If the number of other points contained in the two areas is not 0, it is determined that the other points on the browsing interface are not on the same side of the straight line; If other points on the browsing interface are not on the same side of the drawn straight line, select any two points from the first point, the second point, ... point A, and draw a straight line passing through the two selected points; If other points on the browsing interface are on the same side of the drawn line, the drawn line will be included in the line set; Traverse all situations where two points are selected from the first point, the second point, ... the Ath point to make a straight line, and add all the lines where other points on the browsing interface are on the same side of the made straight line into the straight line set; Get the number of straight lines in the straight line set, recorded as the boundary number; All the straight lines in the straight line set intersect to form several closed areas, and the closed areas whose edges are equal to the number of boundaries are recorded as the areas to be shielded; The shielded area is expanded, and the expanded area is shielded.

[0006] Optionally, the risk duration of obtaining the free browsing portion of each electronic file specifically includes: Acquire an electronic document library, wherein the electronic document library is used to store all electronic documents; The electronic file is a text document; Set up a free browsing section for each electronic document; Users can only browse the free browsing portion of the electronic file that has not been purchased; For an electronic file, obtain the number of times all users browse the free browsing part of this electronic file, and record it as the actual number; Set a number threshold, which is used to determine whether the actual number is valid; If the actual number of times is greater than or equal to the number threshold, the actual number of times is deemed valid; If the actual number of times is less than the number threshold, the actual number of times is deemed invalid; For electronic files with actual valid times, the risk duration of the free browsing part is calculated as follows: Randomly select an electronic file with a valid actual number of times, obtain the total duration of all users browsing the free browsing part of this electronic file, and record it as the total duration; The risk duration of this electronic file = total duration / actual number of times.

[0007] Optionally, the risk duration of obtaining the free browsing portion of each electronic file further includes: For electronic files with invalid actual times, the risk duration of the free browsing part is calculated as follows: Obtain the risk duration of all electronic files with actual valid times and calculate the total risk duration, and record the result as the overall duration; Obtain the word count of all the free browsing parts of the electronic documents with valid actual times and calculate the total word count, and the result is recorded as the overall word count; Calculate the overall duration / total number of words, and record the result as the single word duration; Randomly select an electronic file with an invalid actual number of times, obtain the word count of the free browsing part of this electronic file, and record it as the actual word count; The risk duration of this electronic file = single word duration × actual number of words.

[0008] Optionally, judging the risk level of the user browsing the electronic file according to the risk duration specifically includes: Setting a determination ratio, the determination ratio being used to determine whether the total time for a user to browse the free browsing portion of an electronic file is too long; Obtain the user who is currently browsing the electronic file in the electronic file library and record him as the target user; Obtain the electronic file currently browsed by the target user and record it as the target file; The risk duration of obtaining the free browsing portion of the target file is recorded as the standard duration; Obtain the time the target user spends browsing the target file, recorded as browsing time; If the browsing time ≥ standard time × judgment ratio, it is determined that the total time the target user browses the free browsing part of the electronic file is too long, which poses a risk; If the browsing time is less than the standard time × the judgment ratio, it is determined that the total time the target user spends browsing the free browsing portion of the electronic file is not too long and there is no risk.

[0009] Optionally, judging the risk level of the user browsing the electronic file according to the risk duration further includes: Setting a stay time threshold, wherein the stay time threshold is used to determine whether the total time for which the user browses the free browsing portion of the electronic file is too long; Get the state of the browsing interface of the target user when browsing the target file; The states of the browsing interface include scrolling and static; Obtain the duration of each browsing interface state being static, and select the longest duration as the actual duration; If the actual duration is ≥ the stay duration threshold, it is determined that the total duration of the target user browsing the free browsing portion of the electronic file is too long, and there is a risk; If the actual duration is less than the stay duration threshold, it is determined that the total duration of the target user's browsing of the free browsing portion of the electronic file is not too long and there is no risk.

[0010] Optionally, the step of marking keywords in risky electronic files specifically includes: The target file with risks that the target user is browsing is recorded as a blocked file; Obtain all keywords of the shielded file through natural language processing technology, and form a keyword library of the shielded file, which is recorded as a shielded word library; The keyword is composed of a number of characters, each of which has a circumscribed square of the same area; Get the content of the free browsing part of the shielded file currently displayed on the browsing interface; Determine whether the keywords in the blocked word library appear in the content of the free browsing portion of the blocked file currently displayed on the browsing interface; If the keywords in the blocked word library do not appear in the content of the free browsing part of the blocked file currently displayed on the browsing interface, no processing will be performed; If the keywords in the blocked word library appear in the content of the free browsing portion of the blocked file currently displayed on the browsing interface, the keywords in the blocked word library that appear in the content of the free browsing portion of the blocked file currently displayed on the browsing interface are marked in the browsing interface.

[0011] Optionally, obtaining the intersection set of circles corresponding to the constituent characters of each marked keyword specifically includes: For each marked keyword, obtain all characters constituting it and form a character set; The number of characters in the character set is recorded as the number of characters; For a character, the center of the set of squares surrounding the character is the center point of the character; Get the center point of each character in the character set, and use the center point as the center and twice the length of the diagonal of the square circumscribing the character as the radius to draw a circle, forming N circles and forming a circle set. Each character corresponds to a circle, where N is equal to the number of characters. Randomly select a circle from the circle set, record it as the target circle, and determine whether there is a circle that intersects with the target circle; If it does not exist, the number of groups on the target circle is recorded as 0; If it exists, the target circle and the circle intersecting with the target circle are included in the intersection set of the target circle, and it is determined whether there are other circles intersecting with the circles in the intersection set of the target circle. If not, the number of groups of the target circle is equal to the number of circles in the intersection set of the target circle; if it exists, the circles intersecting with the circles in the intersection set of the target circle are included in the intersection set of the target circle, until no new circles are included in the intersection set of the target circle; and the number of groups of the target circle is equal to the number of circles in the intersection set of the target circle; If the elements in the intersection sets of different circles are all the same, then the intersection sets of these different circles are regarded as the same intersection set.

[0012] Optionally, obtaining the circumference of the intersection set that needs to be shielded as a whole specifically includes: Setting a ratio threshold, wherein the ratio threshold is used to perform overall masking on the characters; Calculate the number of characters × the ratio threshold, and record the result as the number of shielding; Get the number of groups on each circle and sort them in descending order; Select the group number with the largest value and record it as the first number; If the first number is greater than or equal to the shielding number, the characters corresponding to the circles in the intersection set of the circles corresponding to the first number are shielded as a whole; If the first number is less than the shielding number, the group number with the second largest value is selected and recorded as the second number; If the first number + the second number ≥ the shielding number, the characters corresponding to the circles in the intersection set of the circles corresponding to the first number and the second number are shielded as a whole; If the first number + the second number < the shielding number, then the group number with the third largest value is selected and recorded as the third number; If the first number + the second number + the third number ≥ the shielding number, the characters corresponding to the circles in the intersection set of the circles corresponding to the first number, the second number and the third number are shielded as a whole; If the first number + the second number + the third number < the shielding number, then the fourth largest group number is selected and recorded as the fourth number; And so on, until the sum of the selected numbers is greater than or equal to the shielded number, the characters corresponding to the circles in the intersection set of the circles corresponding to each selected number are shielded as a whole.

[0013] Optionally, the shielded area is expanded and shielding is performed on the expanded area, specifically including: Get the geometric center of the area to be shielded, specifically: A plane rectangular coordinate system is randomly established on the browsing interface and recorded as the first coordinate system; Obtain all points on the boundary of the area to be shielded to form a point set; Select any point from the point set and obtain its coordinates in the first coordinate system, recorded as ; Starting from the selected point, along the clockwise direction on the boundary of the area to be shielded, the coordinates of other points in the point set are obtained in turn, and are recorded as , … ; Where Z is equal to the number of points in the point set minus one; The signed area P is calculated by the following formula: ; where i refers to the subscript of X and Y; The geometric center coordinates are calculated by the following formula : ; ; Get the coordinates of the geometric center , recorded as the shape center; Get each edge of the area to be masked; For one edge of the area to be shielded, take the center of the shape as the endpoint and make a ray perpendicular to this edge. The direction of the ray is the extension direction of this edge. Get the extension direction of each edge; Move the straight line of each side of the area to be shielded in the direction of its extension by half the length of the diagonal of the square circumscribing the character; All the straight lines after the movement intersect to form several closed areas, and the closed areas with the number of sides equal to the number of boundaries are recorded as shielded areas; Shield the area covered by the shielding area.

[0014] The present invention has the following beneficial effects: 1. This risk assessment method for file transmission, when obtaining the risk duration of the free browsing part of each electronic file, sets a number threshold to determine whether the actual number is valid. If the actual number is less than the number threshold, it means that the sample size is small at this time, and the risk duration calculated using the actual number has a large error, so the actual number cannot be used to calculate the risk duration. If the actual number is greater than or equal to the number threshold, it means that the sample size is large at this time, and the actual number can be used to calculate the risk duration. This mechanism effectively reduces accidental misjudgments and makes risk assessment more accurate.

[0015] 2. This risk assessment method for file transmission, for electronic files with valid actual times, calculates the total time of all users browsing the free browsing part of this electronic file / the actual number of times of this electronic file, and the result is the average browsing time, which is used as the risk time; for electronic files with invalid actual times, first obtain the single word time of the electronic files with valid actual times, then obtain the actual times of the electronic files with invalid actual times, and then multiply the two to obtain the risk time of the electronic files with invalid actual times; the overall risk time calculation method is used to estimate a reasonable browsing time threshold to ensure the accuracy of risk assessment. This method can effectively reduce the false alarm rate and improve the accuracy of risk identification.

[0016] 3. This risk assessment method for file transmission, when judging the risk level of a user browsing an electronic file, sets a judgment ratio and multiplies the judgment ratio by the risk duration of the electronic file. If the result is greater than the browsing time of the user, it means that the user browses the electronic file for not too long and there is no risk; if the result is less than the browsing time of the user, it means that the user browses the electronic file for too long and may have copied or memorized the file, which is risky; in addition, by setting a stay time threshold and obtaining the user's actual stay time, the two are compared. If the actual stay time is greater than or equal to the stay time threshold, it means that the user stays on a certain part of the electronic file for too long and may have copied or memorized the file, which is risky; otherwise, there is no risk. The combined strategy of judgment ratio + stay time threshold can not only effectively prevent information leakage, but also ensure the browsing experience of normal users. It is an efficient, accurate and adjustable intelligent security protection solution.

[0017] 4. This risk assessment method for file transmission automatically clusters characters by means of a circle intersection set, and performs overall shielding in combination with a ratio threshold, thereby improving the accuracy of sensitive information detection and shielding and reducing misjudgment. First, a circle set is generated for each character using twice the diagonal of the circumscribed square of the character as the radius, and characters with overlapping relationships are classified into the same group by calculating the intersection of the circles. This method can automatically identify highly associated character groups in the text, and even if there are gaps or misalignments between characters, the integrity and accuracy of the recognition can be guaranteed. Secondly, a group quantity sorting mechanism is introduced to sort according to the density of intersecting characters, and the character set that needs to be shielded as a whole is determined by the shielding ratio threshold. This method can give priority to shielding highly associated character areas, ensuring that important sensitive information will not be missed, while avoiding irrelevant characters from being mistakenly shielded. Compared with the traditional method based on single character matching or fixed area shielding, the technical solution of the present invention can dynamically adapt to different text layouts, and even if sensitive characters appear in the form of misalignment, spacing, and intersection, they can still be accurately located and shielded, thereby improving the robustness of information filtering. It can achieve precise control over the scope of information shielding, ensuring both security and the integrity of normal text display.

[0018] 5. This risk assessment method for file transmission achieves accurate expansion of the area to be shielded through geometric center calculation and boundary expansion technology, improves the shielding effect, and avoids information leakage. First, the boundary point set of the area to be shielded is obtained using a plane rectangular coordinate system, and the geometric center coordinates are calculated by a signed area formula to ensure the accuracy of the expansion direction. Secondly, with the geometric center as the endpoint, each side of the area to be shielded is vertically expanded respectively, and the expansion amplitude is determined according to half of the diagonal length of the character's circumscribed square to ensure the rationality of the expansion range; because the determination of the area to be shielded is based on the center of the set of each character, the area to be shielded can only cover the part of the character that needs to be shielded, and half of the diagonal length of the character's circumscribed square can ensure that each character that needs to be shielded is completely shielded; unlike the traditional fixed-size expansion or simple expansion method, the present invention adopts a direction-adaptive expansion strategy, that is, each side is independently expanded according to its own direction, ensuring that the shielded area can accurately cover the relevant sensitive information, even if the shape of the area to be shielded is complex, it can maintain the integrity after expansion. In addition, this method determines the final shielding area by the intersection of the extended straight lines, ensuring that the shielding range is evenly expanded without information omission or excessive occlusion, thereby improving the robustness of the shielding. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Example, see Figure 1 , a risk assessment method for file transmission, comprising: The duration of the risk of obtaining a free viewing portion of each electronic file; Determine the risk level of users browsing electronic files based on the risk duration; Mark keywords in risky electronic files; Obtain the intersection set of circles corresponding to the constituent characters of each marked keyword; Get the area to be shielded, specifically: Get the circumference of the intersection set that needs to be shielded as a whole; For a circle of an intersecting set that needs to be shielded as a whole, obtain the point of the center of each circle in the intersecting set of this circle, and record them as the first point, the second point...the Ath point, where A is equal to the number of groups in this circle; Choose any two points from the first point, the second point, ... point A, and draw a straight line passing through the two selected points; Determine whether other points on the browsing interface are on the same side of the drawn line, specifically: The straight line divides the browsing interface into two areas, which are respectively recorded as the first area and the second area; Get the number of other points in each area. If the number of other points in a certain area is 0, it is considered that other points on the browsing interface are on the same side of the straight line. If the number of other points contained in the two areas is not 0, it is determined that the other points on the browsing interface are not on the same side of the straight line; If other points on the browsing interface are not on the same side of the drawn straight line, select any two points from the first point, the second point, ... point A, and draw a straight line passing through the two selected points; If other points on the browsing interface are on the same side of the drawn line, the drawn line will be included in the line set; Traverse all situations where two points are selected from the first point, the second point, ... the Ath point to make a straight line, and add all the lines where other points on the browsing interface are on the same side of the made straight line into the straight line set; Get the number of straight lines in the straight line set, recorded as the boundary number; All the straight lines in the straight line set intersect to form several closed areas, and the closed areas whose edges are equal to the number of boundaries are recorded as the areas to be shielded; The shielded area is expanded, and the expanded area is shielded.

[0022] The risk duration of obtaining the free browsing portion of each electronic file specifically includes: Acquire an electronic document library, wherein the electronic document library is used to store all electronic documents; The electronic file is a text document; Set up a free browsing section for each electronic file; Users can only browse the free browsing portion of the electronic file that has not been purchased; For an electronic file, obtain the number of times all users browse the free browsing part of this electronic file, and record it as the actual number; Set a number threshold, which is used to determine whether the actual number is valid; If the actual number of times is greater than or equal to the number threshold, the actual number of times is deemed valid; If the actual number of times is less than the number threshold, the actual number of times is deemed invalid; When obtaining the risk duration of the free browsing part of each electronic file, a frequency threshold is set to determine whether the actual number of times is valid. If the actual number of times is less than the frequency threshold, it means that the sample size is small at this time, and the error of the risk duration calculated by the actual number of times is large, so the actual number of times cannot be used to calculate the risk duration. If the actual number of times is greater than or equal to the frequency threshold, it means that the sample size is large at this time, and the actual number of times can be used to calculate the risk duration. This mechanism effectively reduces accidental misjudgments and makes risk assessment more accurate; For electronic files with actual valid times, the risk duration of the free browsing part is calculated as follows: Randomly select an electronic file with a valid actual number of times, obtain the total duration of all users browsing the free browsing part of this electronic file, and record it as the total duration; The risk duration of this electronic file = total duration / actual number of times.

[0023] The risk duration of obtaining the free browsing portion of each electronic file also includes: For electronic files with invalid actual times, the risk duration of the free browsing part is calculated as follows: Obtain the risk duration of all electronic files with actual valid times and calculate the total risk duration, and record the result as the overall duration; Obtain the word count of all the free browsing parts of the electronic documents with valid actual times and calculate the total word count, and the result is recorded as the overall word count; Calculate the overall duration / total number of words, and record the result as the single word duration; Randomly select an electronic file with an invalid actual number of times, obtain the word count of the free browsing part of this electronic file, and record it as the actual word count; The risk duration of this electronic document = single word duration × actual number of words; For electronic files with valid actual times, calculate the total time all users spend browsing the free browsing part of this electronic file / the actual number of times this electronic file is browsed, and the result is the average browsing time, which is used as the risk time; for electronic files with invalid actual times, first obtain the single-word duration of the electronic files with valid actual times, then obtain the actual times of the electronic files with invalid actual times, and then multiply the two to obtain the risk time of the electronic files with invalid actual times; use the overall risk time calculation method to estimate a reasonable browsing time threshold to ensure the accuracy of risk assessment. This method can effectively reduce the false alarm rate and improve the accuracy of risk identification.

[0024] The step of judging the risk level of a user browsing electronic files according to the risk duration specifically includes: Setting a determination ratio, the determination ratio being used to determine whether the total time for a user to browse the free browsing portion of an electronic file is too long; Obtain the user who is currently browsing the electronic file in the electronic file library and record him as the target user; Obtain the electronic file currently browsed by the target user and record it as the target file; The risk duration of obtaining the free browsing portion of the target file is recorded as the standard duration; Obtain the time the target user spends browsing the target file, recorded as browsing time; If the browsing time ≥ standard time × judgment ratio, it is determined that the total time the target user browses the free browsing part of the electronic file is too long, which poses a risk; If the browsing time is less than the standard time × the judgment ratio, it is determined that the total time the target user spends browsing the free browsing portion of the electronic file is not too long and there is no risk.

[0025] The step of judging the risk level of the user browsing the electronic file according to the risk duration also includes: Setting a stay time threshold, wherein the stay time threshold is used to determine whether the total time for which the user browses the free browsing portion of the electronic file is too long; Get the state of the browsing interface of the target user when browsing the target file; The states of the browsing interface include scrolling and static; Obtain the duration of each browsing interface state being static, and select the longest duration as the actual duration; If the actual duration is ≥ the stay duration threshold, it is determined that the total duration of the target user browsing the free browsing portion of the electronic file is too long, and there is a risk; If the actual duration is less than the stay duration threshold, it is determined that the total duration of the target user browsing the free browsing portion of the electronic file is not too long and there is no risk; When judging the risk level of a user browsing an electronic file, a judgment ratio is set and multiplied by the risk duration of the electronic file. If the result is greater than the user's browsing time, it means that the user has browsed the electronic file for not too long and there is no risk. If the result is less than the user's browsing time, it means that the user has browsed the electronic file for too long and may have copied or memorized the file, which is risky. In addition, a stay time threshold is set and the user's actual stay time is obtained, and the two are compared. If the actual stay time threshold is greater than or equal to the stay time threshold, it means that the user has stayed on a certain part of the electronic file for too long and may have copied or memorized the file, which is risky. Otherwise, there is no risk. The combined strategy of judgment ratio + stay time threshold can not only effectively prevent information leakage, but also ensure the browsing experience of normal users. It is an efficient, accurate and adjustable intelligent security protection solution.

[0026] The marking of keywords in risky electronic files specifically includes: The target file with risks that the target user is browsing is recorded as a blocked file; Obtain all keywords of the shielded file through natural language processing technology, and form a keyword library of the shielded file, which is recorded as a shielded word library; The keyword is composed of a number of characters, each of which has a circumscribed square of the same area; Get the content of the free browsing part of the shielded file currently displayed on the browsing interface; Determine whether the keywords in the blocked word library appear in the content of the free browsing portion of the blocked file currently displayed on the browsing interface; If the keywords in the blocked word library do not appear in the content of the free browsing part of the blocked file currently displayed on the browsing interface, no processing will be performed; If the keywords in the blocked word library appear in the content of the free browsing portion of the blocked file currently displayed on the browsing interface, the keywords in the blocked word library that appear in the content of the free browsing portion of the blocked file currently displayed on the browsing interface are marked in the browsing interface.

[0027] The step of obtaining the intersection set of circles corresponding to the constituent characters of each marked keyword specifically includes: For each marked keyword, obtain all characters constituting it and form a character set; The number of characters in the character set is recorded as the number of characters; For a character, the center of the set of squares circumscribing the character is the center point of the character; Get the center point of each character in the character set, and use the center point as the center and twice the length of the diagonal of the square circumscribing the character as the radius to draw a circle, forming N circles and forming a circle set. Each character corresponds to a circle, where N is equal to the number of characters. Randomly select a circle from the circle set, record it as the target circle, and determine whether there is a circle that intersects with the target circle; If it does not exist, the number of groups on the target circle is recorded as 0; If it exists, the target circle and the circle intersecting with the target circle are included in the intersection set of the target circle, and it is determined whether there are other circles intersecting with the circles in the intersection set of the target circle. If not, the number of groups of the target circle is equal to the number of circles in the intersection set of the target circle; if it exists, the circles intersecting with the circles in the intersection set of the target circle are included in the intersection set of the target circle, until no new circles are included in the intersection set of the target circle; and the number of groups of the target circle is equal to the number of circles in the intersection set of the target circle; If the elements in the intersection sets of different circles are all the same, then the intersection sets of these different circles are regarded as the same intersection set.

[0028] The obtaining of the circumference of the intersection set that needs to be shielded as a whole specifically includes: Setting a ratio threshold, wherein the ratio threshold is used to perform overall masking on the characters; Calculate the number of characters × the ratio threshold, and record the result as the number of shielding; Get the number of groups on each circle and sort them in descending order; Select the group number with the largest value and record it as the first number; If the first number is greater than or equal to the shielding number, the characters corresponding to the circles in the intersection set of the circles corresponding to the first number are shielded as a whole; If the first number is less than the shielding number, the group number with the second largest value is selected and recorded as the second number; If the first number + the second number ≥ the shielding number, the characters corresponding to the circles in the intersection set of the circles corresponding to the first number and the second number are shielded as a whole; If the first number + the second number < the shielding number, then the group number with the third largest value is selected and recorded as the third number; If the first number + the second number + the third number ≥ the shielding number, the characters corresponding to the circles in the intersection set of the circles corresponding to the first number, the second number and the third number are shielded as a whole; If the first number + the second number + the third number < the shielding number, then the fourth largest group number is selected and recorded as the fourth number; This process is repeated until the sum of the selected numbers is greater than or equal to the shielded number, and the characters corresponding to the circles in the intersection set of the circles corresponding to each selected number are shielded as a whole. The characters are automatically clustered by the method of the circle intersection set, and the characters are shielded as a whole by combining the ratio threshold, which improves the accuracy of sensitive information detection and shielding and reduces misjudgment. First, the circle set is generated for each character by using twice the diagonal of the circumscribed square of the character as the radius, and the characters with overlapping relationships are classified into the same group by calculating the intersection of the circles. This method can automatically identify the highly associated character groups in the text, and even if there are gaps or misalignments between the characters, the integrity and accuracy of the recognition can be guaranteed. Secondly, a group quantity sorting mechanism is introduced to sort according to the density of the intersecting characters, and the character set that needs to be shielded as a whole is determined by the shielding ratio threshold. This method can give priority to shielding the highly associated character area, ensuring that important sensitive information will not be missed, and avoiding irrelevant characters from being mistakenly shielded. Compared with the traditional method based on single character matching or fixed area shielding, the technical solution of the present invention can dynamically adapt to different text layouts, even if sensitive characters appear in the form of misalignment, spacing, and intersection, they can still be accurately located and shielded, thereby improving the robustness of information filtering. Accurately control the range of information shielding, which not only ensures security, but also takes into account the integrity of normal text display.

[0029] Expand the shielded area and shield the expanded area, including: Get the geometric center of the area to be shielded, specifically: A plane rectangular coordinate system is randomly established on the browsing interface and recorded as the first coordinate system; Obtain all points on the boundary of the area to be shielded to form a point set; Select any point from the point set and obtain its coordinates in the first coordinate system, recorded as ; Starting from the selected point, along the clockwise direction on the boundary of the area to be shielded, the coordinates of other points in the point set are obtained in turn, and are recorded as , … ; Where Z is equal to the number of points in the point set minus one; The signed area P is calculated by the following formula: ; where i refers to the subscript of X and Y; The geometric center coordinates are calculated by the following formula : ; ; Get the coordinates of the geometric center , recorded as the shape center; Get each edge of the area to be masked; For one edge of the area to be shielded, take the center of the shape as the endpoint and make a ray perpendicular to this edge. The direction of the ray is the extension direction of this edge. Get the extension direction of each edge; Move the straight line of each side of the area to be shielded in the direction of its extension by half the length of the diagonal of the square circumscribing the character; All the straight lines after the movement intersect to form several closed areas, and the closed areas with the number of sides equal to the number of boundaries are recorded as shielded areas; Performing shielding processing on the area covered by the shielding area; Through the geometric center calculation and boundary expansion technology, the accurate expansion of the area to be shielded is achieved, the shielding effect is improved, and information leakage is avoided. First, the boundary point set of the area to be shielded is obtained by using the plane rectangular coordinate system, and the geometric center coordinates are calculated by the signed area formula to ensure the accuracy of the expansion direction. Secondly, with the geometric center as the endpoint, each side of the shielded area is vertically expanded respectively, and the expansion amplitude is determined according to half of the diagonal length of the character's circumscribed square to ensure the rationality of the expansion range; because the determination of the area to be shielded is based on the set center of each character, the area to be shielded can only cover the part of the character to be shielded, and half of the diagonal length of the character's circumscribed square can ensure that each character to be shielded is completely shielded; different from the traditional fixed size expansion or simple expansion method, the present invention adopts a direction adaptive expansion strategy, that is, each side is independently expanded according to its own direction, ensuring that the shielded area can accurately cover the relevant sensitive information, even if the shape of the area to be shielded is complex, it can maintain the integrity after expansion. In addition, the method determines the final shielding area by the intersection of the straight lines after expansion, ensuring that the shielding range is evenly expanded, and there will be no information omission or excessive occlusion, thereby improving the robustness of the shielding.

[0030] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0031] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A risk assessment method for file transmission, characterized in that: include: The duration of the risk of obtaining a free viewing portion of each electronic file; Determine the risk level of users browsing electronic files based on the risk duration; Mark keywords in risky electronic files; Obtain the intersection set of circles corresponding to the constituent characters of each marked keyword; Get the area to be shielded, specifically: Get the circumference of the intersection set that needs to be shielded as a whole; For a circle of an intersecting set that needs to be shielded as a whole, obtain the point of the center of each circle in the intersecting set of this circle, and record them as the first point, the second point...the Ath point, where A is equal to the number of groups in this circle; Choose any two points from the first point, the second point, ... point A, and draw a straight line passing through the two selected points; Determine whether other points on the browsing interface are on the same side of the drawn line, specifically: The straight line divides the browsing interface into two areas, which are respectively recorded as the first area and the second area; Get the number of other points in each area. If the number of other points in a certain area is 0, it is considered that other points on the browsing interface are on the same side of the straight line. If the number of other points contained in the two areas is not 0, it is determined that the other points on the browsing interface are not on the same side of the straight line; If other points on the browsing interface are not on the same side of the drawn straight line, select any two points from the first point, the second point, ... point A, and draw a straight line passing through the two selected points; If other points on the browsing interface are on the same side of the drawn line, the drawn line will be included in the line set; Traverse all situations where two points are selected from the first point, the second point, ... the Ath point to make a straight line, and add all the lines where other points on the browsing interface are on the same side of the made straight line into the straight line set; Get the number of straight lines in the straight line set, recorded as the boundary number; All the straight lines in the straight line set intersect to form several closed areas, and the closed areas whose edges are equal to the number of boundaries are recorded as the areas to be shielded; The shielded area is expanded, and the expanded area is shielded.

2. A risk assessment method for file transmission according to claim 1, characterized in that: The risk duration of obtaining the free browsing portion of each electronic file specifically includes: Acquire an electronic document library, wherein the electronic document library is used to store all electronic documents; The electronic file is a text document; Set up a free browsing section for each electronic document; Users can only browse the free browsing portion of the electronic file that has not been purchased; For an electronic file, obtain the number of times all users browse the free browsing part of this electronic file, and record it as the actual number; Set a number threshold, which is used to determine whether the actual number is valid; If the actual number of times is greater than or equal to the number threshold, the actual number of times is deemed valid; If the actual number of times is less than the number threshold, the actual number of times is deemed invalid; For electronic files with actual valid times, the risk duration of the free browsing part is calculated as follows: Randomly select an electronic file with a valid actual number of times, obtain the total duration of all users browsing the free browsing part of this electronic file, and record it as the total duration; The risk duration of this electronic file = total duration / actual number of times.

3. A risk assessment method for file transmission according to claim 2, characterized in that: The risk duration of obtaining the free browsing portion of each electronic file also includes: For electronic files with invalid actual times, the risk duration of the free browsing part is calculated as follows: Obtain the risk duration of all electronic files with actual valid times and calculate the total risk duration, and record the result as the overall duration; Obtain the word count of all the free browsing parts of the electronic documents with valid actual times and calculate the total word count, and the result is recorded as the overall word count; Calculate the overall duration / total number of words, and record the result as the single word duration; Randomly select an electronic file with an invalid actual number of times, obtain the word count of the free browsing part of this electronic file, and record it as the actual word count; The risk duration of this electronic file = single word duration × actual number of words.

4. A risk assessment method for file transmission according to claim 1, characterized in that: The step of judging the risk level of a user browsing electronic files according to the risk duration specifically includes: Setting a determination ratio, the determination ratio being used to determine whether the total time for a user to browse the free browsing portion of an electronic file is too long; Obtain the user who is currently browsing the electronic file in the electronic file library and record him as the target user; Obtain the electronic file currently browsed by the target user and record it as the target file; The risk duration of obtaining the free browsing portion of the target file is recorded as the standard duration; Obtain the time the target user spends browsing the target file, recorded as browsing time; If the browsing time ≥ standard time × judgment ratio, it is determined that the total time the target user browses the free browsing part of the electronic file is too long, which poses a risk; If the browsing time is less than the standard time × the judgment ratio, it is determined that the total time the target user spends browsing the free browsing portion of the electronic file is not too long and there is no risk.

5. A risk assessment method for file transmission according to claim 4, characterized in that: The step of judging the risk level of the user browsing the electronic file according to the risk duration also includes: Setting a stay time threshold, wherein the stay time threshold is used to determine whether the total time for which the user browses the free browsing portion of the electronic file is too long; Get the state of the browsing interface of the target user when browsing the target file; The states of the browsing interface include scrolling and static; Obtain the duration of each browsing interface state being static, and select the longest duration as the actual duration; If the actual duration is ≥ the stay duration threshold, it is determined that the total duration of the target user browsing the free browsing portion of the electronic file is too long, and there is a risk; If the actual duration is less than the stay duration threshold, it is determined that the total duration of the target user's browsing of the free browsing portion of the electronic file is not too long and there is no risk.

6. A risk assessment method for file transmission according to claim 1, characterized in that: The marking of keywords in risky electronic files specifically includes: The target file with risks that the target user is browsing is recorded as a blocked file; Obtain all keywords of the shielded file through natural language processing technology, and form a keyword library of the shielded file, which is recorded as a shielded word library; The keyword is composed of a number of characters, each of which has a circumscribed square of the same area; Get the content of the free browsing part of the shielded file currently displayed on the browsing interface; Determine whether the keywords in the blocked word library appear in the content of the free browsing portion of the blocked file currently displayed on the browsing interface; If the keywords in the blocked word library do not appear in the content of the free browsing part of the blocked file currently displayed on the browsing interface, no processing will be performed; If the keywords in the blocked word library appear in the content of the free browsing portion of the blocked file currently displayed on the browsing interface, the keywords in the blocked word library that appear in the content of the free browsing portion of the blocked file currently displayed on the browsing interface are marked in the browsing interface.

7. A risk assessment method for file transmission according to claim 1, characterized in that: The step of obtaining the intersection set of circles corresponding to the constituent characters of each marked keyword specifically includes: For each marked keyword, obtain all characters constituting it and form a character set; The number of characters in the character set is recorded as the number of characters; For a character, the center of the set of squares circumscribing the character is the center point of the character; Get the center point of each character in the character set, and use the center point as the center and the radius as twice the length of the diagonal of the square circumscribing the character to draw a circle, forming N circles and forming a circle set. Each character corresponds to a circle, where N is equal to the number of characters. Randomly select a circle from the circle set, record it as the target circle, and determine whether there is a circle that intersects with the target circle; If it does not exist, the number of groups on the target circle is recorded as 0; If so, the target circle and the circle intersecting with the target circle are included in the intersection set of the target circle, and it is determined whether there are other circles intersecting with the circles in the intersection set of the target circle. If not, the number of groups of the target circle is equal to the number of circles in the intersection set of the target circle; if so, the circles intersecting with the circles in the intersection set of the target circle are included in the intersection set of the target circle, until no new circles are included in the intersection set of the target circle; and the number of groups of the target circle is equal to the number of circles in the intersection set of the target circle; If the elements in the intersection sets of different circles are all the same, then the intersection sets of these different circles are regarded as the same intersection set.

8. A risk assessment method for file transmission according to claim 1, characterized in that: The obtaining of the circumference of the intersection set that needs to be shielded as a whole specifically includes: Setting a ratio threshold, wherein the ratio threshold is used to perform overall masking on the characters; Calculate the number of characters × the ratio threshold, and record the result as the number of shielding; Get the number of groups on each circle and sort them in descending order; Select the group number with the largest value and record it as the first number; If the first number is greater than or equal to the shielding number, the characters corresponding to the circles in the intersection set of the circles corresponding to the first number are shielded as a whole; If the first number is less than the shielding number, the group number with the second largest value is selected and recorded as the second number; If the first number + the second number ≥ the shielding number, the characters corresponding to the circles in the intersection set of the circles corresponding to the first number and the second number are shielded as a whole; If the first number + the second number < the shielding number, then the group number with the third largest value is selected and recorded as the third number; If the first number + the second number + the third number ≥ the shielding number, the characters corresponding to the circles in the intersection set of the circles corresponding to the first number, the second number and the third number are shielded as a whole; If the first number + the second number + the third number < the shielding number, then the fourth largest group number is selected and recorded as the fourth number; And so on, until the sum of the selected numbers is greater than or equal to the shielded number, the characters corresponding to the circles in the intersection set of the circles corresponding to each selected number are shielded as a whole.

9. A risk assessment method for file transmission according to claim 1, characterized in that: Expand the shielded area and shield the expanded area, including: Get the geometric center of the area to be shielded, specifically: A plane rectangular coordinate system is randomly established on the browsing interface and recorded as the first coordinate system; Obtain all points on the boundary of the area to be shielded to form a point set; Select any point from the point set and obtain its coordinates in the first coordinate system, recorded as ; Starting from the selected point, along the clockwise direction on the boundary of the area to be shielded, the coordinates of other points in the point set are obtained in turn, and are recorded as , … ; The signed area P is calculated by the following formula: ； The geometric center coordinates are calculated by the following formula : ； ； Get the coordinates of the geometric center , recorded as the shape center; Get each edge of the area to be masked; For one edge of the area to be shielded, take the center of the shape as the endpoint and make a ray perpendicular to this edge. The direction of the ray is the extension direction of this edge. Get the extension direction of each edge; Move the straight line of each side of the area to be shielded in the direction of its extension by half the length of the diagonal of the square circumscribing the character; All the straight lines after the movement intersect to form several closed areas, and the closed areas with the number of sides equal to the number of boundaries are recorded as shielded areas; Shield the area covered by the shielding area.

Images