CN108139856B - Signature authentication method, terminal, stylus and system - Google Patents

Abstract

The embodiment of the invention relates to a signature authentication method, a terminal, a handwriting pen and a system. The method comprises the steps that when a user signs on a touch panel of the terminal through a handwriting pen, the terminal detects first signature data, wherein the first signature data comprise coordinate information of a contact point of the handwriting pen and the touch panel and pressure information of the handwriting pen on the touch panel at the contact point; and the terminal receives second signature data sent by the handwriting pen, wherein the second signature data comprises the motion track information of the handwriting pen and the pressure information of the user on the handwriting pen, which are detected by the handwriting pen when the user signs on the touch panel through the handwriting pen. And matching and comparing the first signature data and the second signature data with pre-stored signature template data to obtain a matching rate. And when the matching rate is not lower than a preset matching rate threshold value, the signature passes the authentication. According to the embodiment of the invention, more user signature characteristic data are extracted through the stylus pen, the difficulty of an attacker simulating user signature information is increased, and the safety of the signature authentication system is improved.

Description

Signature authentication method, terminal, stylus and system

technical field

The invention relates to the technical field of stylus signature authentication, in particular to a signature authentication method, a terminal, a stylus and a system.

Background technique

The stylus signature technology has become an important technology to confirm the user's identity in the virtual environment of the network system. The user uses a stylus to input a handwritten signature on the touch panel of the terminal for authentication, and the terminal detects the relevant data of the handwritten signature through the touch panel and the sensor. The terminal compares and matches the relevant data of the detected signature with the pre-stored signature template data to identify the authenticity of the signature and determine whether the user-input handwritten signature has passed the authentication. Among them, the relevant data of the signature detected by the terminal includes information such as the signature image information and the pressure information of the stylus on the touch panel.

In the prior art, when an attacker who tries to imitate the user's handwritten signature obtains the user's signature template data, presents it to the terminal authentication system in turn, forges the user's handwritten signature, and passes the signature authentication. After passing the authentication by forging the user's handwritten signature, an attacker can illegally obtain the relevant permissions of the user, further threatening the personal or property safety of the user.

In the prior art, only the relevant data of the handwritten signature detected by the terminal is used as a signature template, which is highly imitative, so the security of the existing handwritten signature authentication system is poor.

SUMMARY OF THE INVENTION

The embodiments of the present invention relate to a signature authentication method, a terminal, a handwriting pen and a system, and improve the security of the handwritten signature authentication system.

In a first aspect, an embodiment of the present invention provides a signature authentication method. The method includes: when a user signs on a touch panel of a terminal with a stylus, the terminal detects first signature data, where the first signature data includes the stylus and the touch panel. The coordinate information of the contact point of the touch panel and the pressure information of the stylus on the touch panel at the contact point; and the terminal receives the second signature data sent by the stylus, and the second signature data includes the stylus detected when the user touches the touch panel with the stylus. The movement track information of the stylus and the pressure information of the user on the stylus when signing on the panel. Matching and comparing the first signature data and the second signature data with the pre-stored signature template data to obtain a matching rate. When the matching rate is not lower than the preset matching rate threshold, the signature authentication is passed.

In the embodiment of the present invention, when the user uses a stylus to input a handwritten signature on the touch panel of the terminal, the stylus is used to extract more user signature feature data, compare and match, increase the difficulty of an attacker imitating the user signature information, and improve the signature authentication. system security.

In a possible implementation, the sampling time and sampling frequency of the first signature data and the second signature data are kept synchronized.

The signature authentication system provided by the embodiment of the present invention enables the attacker to imitate the user's hand movements while imitating the user's handwriting, which greatly improves the security of the signature authentication system.

In a possible implementation manner, the signature corresponds to a first signature feature point and a second signature feature point, the first signature feature point includes at least one point in a set consisting of contact points, and the second signature feature point includes At least one point in the set of points in the motion trajectory of the area outside the panel; extract the data corresponding to the first signature feature point and the second signature feature point from the first signature data and the second signature data; The data corresponding to the second signature feature point is matched and compared with the data of each feature point in the signature template data to obtain a matching rate.

In a possible implementation manner, the data corresponding to the first signature feature point includes: coordinate information of the contact point corresponding to the first signature feature point, pressure information of the stylus on the touch panel at the contact point corresponding to the first signature feature point and the position information of the stylus and the pressure information of the user on the stylus when the sampling time of the first signature feature point is the same; wherein, the position information of the stylus is obtained from the movement track information of the stylus.

Wherein, after the coordinate system for detecting the movement trajectory of the stylus pen and the coordinate system for detecting the coordinates of the contact point are transformed and unified, the position coordinates of the stylus pen end in the area where the touch panel is located coincide with the position coordinates of the contact point.

In a possible implementation manner, the data corresponding to the second signature feature point includes: position information of the stylus corresponding to the second signature feature point and pressure information of the user on the stylus.

In a possible implementation manner, the second signature data further includes: acceleration of the stylus detected by the stylus when the user signs on the touch panel with the stylus, pressure area information of the stylus subjected to the user's pressure, and pressure The shape information of the area, and the distance information from the pressed area of the stylus to the end of the stylus.

In a possible implementation manner, the first signature feature point specifically includes one or more of the following points, the first contact point, the last contact point, a discontinuous contact point, or a contact point with a large curvature change.

Specifically, the discontinuous contact points correspond to the starting points of different strokes in the signature. Points with large curvature transformations correspond to bending points in the stroke.

In a possible implementation manner, the second signature feature point specifically includes one or more of the following points: the point with the largest curvature in the curve corresponding to the motion trajectory of each discontinuous stylus in the area outside the touch panel , or the point farthest from the touch panel in the curve corresponding to the movement trajectory of each discontinuous stylus in the area outside the touch panel.

Among them, the point with the largest curvature in the curve corresponding to the movement trajectory of each discontinuous stylus, or the point farthest from the touch panel in the curve corresponding to the movement trajectory of each discontinuous stylus corresponds to the point between the two strokes The highest point of the stylus.

In a possible implementation, the first signature feature point is extracted from the contact point; the movement trajectory of the pen end of the stylus is projected on the first plane where the touch panel is located to obtain the first movement trajectory of the pen end of the stylus pen; The motion trajectory of the pen end is projected on the second plane and the third plane perpendicular to the first plane to obtain the second motion trajectory and the third motion trajectory of the pen end of the stylus, and the second plane is perpendicular to the third plane; from the first motion trajectory Extract the second signature feature point from at least one motion track in the second motion track and the third motion track; extract the data corresponding to the first signature feature point and the second signature feature point from the first signature data and the second signature data ; Match and compare the data corresponding to the first signature feature point and the second signature feature point with the data of each feature point in the signature template data to obtain a matching rate.

In a possible implementation manner, a matching rate threshold is preset according to the environment where the terminal is located.

The embodiment of the present invention can also set different matching rate thresholds according to the environment where the terminal is located, which can adapt to the actual needs of users and has a good application prospect.

In a second aspect, an embodiment of the present invention provides a signature authentication method, the method includes: when a user signs on a touch panel of a terminal with a stylus, the stylus detects second signature data, and the second signature data includes the stylus The stylus sends the second signature data to the terminal, so that the terminal determines whether the signature authentication is passed according to the second signature data and the first signature data detected by the terminal, and the first signature data It includes the coordinate information of the contact point between the stylus and the touch panel and the pressure information of the stylus on the touch panel at the contact point.

In a possible implementation manner, the second signature data further includes: acceleration of the stylus detected by the stylus when the user signs on the touch panel with the stylus, pressure area information of the stylus subjected to the user's pressure, and pressure The shape information of the area, and the distance information from the pressed area of the stylus to the end of the stylus.

Specifically, the second signature feature data reflects the hand motion feature of the user. When different users input handwritten signatures, there may be differences in the strength, shape, and distance between the holding area and the end of the pen.

In a possible implementation, the sampling time and sampling frequency of the first signature data and the second signature data are kept synchronized.

In a third aspect, an embodiment of the present invention provides a terminal, where the terminal includes: a touch panel, a display panel, a sensor, a processor, a memory, and a communication unit.

The touch panel is used to receive the signature entered by the user through the stylus. Display panel to display an image of the signature. The touch panel is also used to detect the coordinate information of the contact point between the stylus and the touch panel. The sensor is used to detect the pressure information of the stylus on the touch panel at the contact point; the coordinate information of the contact point and the pressure information of the stylus on the touch panel at the contact point constitute the first signature data. The communication unit is used to establish a communication connection with the stylus, and receive the second signature data sent by the stylus. The second signature data includes the movement track information of the stylus detected by the stylus when the user signs on the touch panel through the stylus, and User pressure information on the stylus. The memory is used to store the preset matching rate threshold. The processor is used to match and compare the first signature data and the second signature data with the pre-stored signature template data to obtain a matching rate; when the matching rate is not lower than the preset matching rate threshold, instruct the display panel to display the signature verification passed. prompt information. The display panel is also used to display the prompt information that the signature verification is passed.

In a possible implementation manner, the processor is further configured to send control information on the sampling time and sampling frequency of the stylus to the stylus, so as to control the sampling time and sampling frequency of the first signature data and the second signature data to maintain Synchronize.

In a possible implementation manner, the signature corresponds to a first signature feature point and a second signature feature point, the first signature feature point includes at least one point in a set consisting of contact points, and the second signature feature point includes at least one point in the set of points in the motion trajectory of the area outside the panel; the processor is specifically configured to extract data corresponding to the first signature feature point and the second signature feature point from the first signature data and the second signature data; The data corresponding to the first signature feature point and the second signature feature point are matched and compared with the data of each feature point in the signature template data to obtain a matching rate.

In a possible implementation, the processor is specifically configured to extract the first signature feature point from the contact point; project the motion trajectory of the pen end of the stylus on the first plane where the touch panel is located to obtain the first signature of the pen end of the stylus. Movement trajectory; the movement trajectory of the stylus pen end is projected on the second plane and the third plane perpendicular to the first plane to obtain the second movement trajectory and the third movement trajectory of the stylus pen end, and the second plane is perpendicular to the third plane. ; Extract the second signature feature point from at least one of the first motion track, the second motion track and the third motion track; Extract the first signature feature point and the second signature data from the first signature data and the second signature data The data corresponding to the signature feature point; the data corresponding to the first signature feature point and the second signature feature point are matched and compared with the data of each feature point in the signature template data to obtain the matching rate.

In a possible implementation manner, the processor is further configured to determine the environment where the terminal is located according to the network to which the communication unit is connected, and preset a matching rate threshold according to the environment where the terminal is located.

In a fourth aspect, an embodiment of the present invention provides a stylus pen, where the stylus pen includes: a sensor unit, a processor, and a communication unit.

The sensor unit is used for detecting the movement track information of the stylus pen and the pressure information of the user on the stylus pen when the user signs on the touch panel of the terminal with the stylus pen.

The processor is configured to convert the movement track information of the stylus and the pressure information of the user on the stylus into second signature data that can be processed by the terminal, and instruct the communication unit to send the data to the terminal.

The communication unit is configured to establish a communication connection with the terminal and send the second signature data to the terminal.

In a possible implementation manner, the sensor unit is further configured to detect the acceleration of the stylus, the pressure area information and the pressure area of the stylus when the stylus is pressed by the user when the user signs on the touch panel of the terminal The shape information of the stylus, and the distance information of the pressed area of the stylus from the end of the stylus.

In a possible implementation manner, the communication unit is further configured to receive control information on the sampling time and sampling frequency of the sensor unit sent by the terminal, so as to control the sampling time of the first signature data and the second signature data synchronized with the sampling frequency.

In a fifth aspect, an embodiment of the present invention provides a signature authentication system, including the terminal provided in the foregoing third aspect and the stylus provided in the foregoing fourth aspect.

In the signature authentication method, terminal, stylus, and system provided by the embodiments of the present invention, the terminal and the stylus simultaneously detect the relevant data of the signature, compare and match the relevant data of the signature with the pre-stored signature template data, and determine whether the signature is authenticated according to the matching rate. pass. In this embodiment of the present invention, when a user uses a stylus to input a handwritten signature on the touch panel of a terminal, the stylus is used to extract more user signature feature data and compare and match, so that the attacker can imitate the user's handwriting while imitating the user's handwriting. It increases the difficulty for attackers to imitate the user's signature information, and greatly improves the security of the signature authentication system.

Description of drawings

1 is a schematic diagram of the architecture of a signature authentication system provided by an embodiment of the present invention;

2 is a schematic diagram of a terminal architecture provided by the implementation of the present invention;

FIG. 3 is a schematic diagram of a stylus structure provided by an embodiment of the present invention;

4 is a schematic diagram of a coordinate system and a signature of a signature authentication system provided by an embodiment of the present invention;

FIG. 5 is a signaling interaction diagram of a method for a signature authentication system provided by an embodiment of the present invention.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the present invention. examples, but not all examples. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The “attacker” mentioned in the embodiment of the present invention refers to an attempt to imitate the characteristics of the handwritten signature input by the user, and imitate the relevant characteristics of the user’s hand movements in the process of imitating the user’s handwriting signature input, so as to pass the authentication of the terminal. user. The "other users" mentioned in the embodiments of the present invention refer to the user A who inputs the handwritten signature A, and the "other users" is different from the user A who inputs the handwritten signature A. Wherein, each user has a one-to-one correspondence with the relevant data of the user's handwritten signature. A refers to any user.

The "contact point" mentioned in the embodiments of the present invention refers to the contact point between the stylus pen and the touch panel. It can be understood that the contact points of the stylus and the touch panel constitute a handwritten signature image.

The "movement trajectory" of the stylus mentioned in the embodiment of the present invention refers to a curve composed of points corresponding to a certain point on the stylus at different positions in space. For example, the curve formed by the different points drawn by the stylus end in space is the motion trajectory of the stylus pen end.

The "pen-holding posture" of the user mentioned in the embodiments of the present invention refers to the pressure-bearing area and/or the pressure-bearing shape of the stylus when the user holds the pen. The "pen-holding strength" of the user mentioned in the embodiment of the present invention refers to the pressure information on the stylus when the user holds the pen. It should be noted that different users may correspond to different feature information such as pen-holding postures and pen-holding strengths.

The "curvature" mentioned in the embodiments of the present invention refers to a numerical value of the degree of curvature of a curve at a certain point. The greater the curvature, the greater the curvature of the curve. "Points with larger curvature changes" refer to points where curvature bending changes are more pronounced. For example, for a specific word in the signature, there are two points with large curvature changes in the stroke "hook (湚)". The stroke "horizontal line-" does not have a point with a large curvature change.

The "matching rate" mentioned in the embodiment of the present invention refers to the matching degree after the data is compared with the data.

The "matching rate threshold" mentioned in the embodiment of the present invention refers to a matching rate threshold (matching rate threshold) that can be preset by the terminal when the user inputs a handwritten signature for authentication. When the user inputs a handwritten signature for authentication, when the matching rate between the relevant data of the handwritten signature and the signature template data is not lower than the matching rate threshold, the terminal may determine that the user's handwritten signature has passed the authentication. For example, if the matching rate threshold is 70%, and the matching rate between the relevant data of the user's handwritten signature calculated by the terminal and the signature template data is 75%, since 75%>70%, the terminal determines that the user's handwritten signature has passed the authentication.

The "preset" mentioned in the embodiment of the present invention refers to a preset setting. The "preset matching rate threshold" refers to setting a matching rate threshold in advance before the user enters a handwritten signature for authentication, so as to determine whether the authentication is passed.

The "first signature data" mentioned in the embodiment of the present invention refers to data related to the signature detected by the terminal, such as image information of the signature, pressure information of the stylus on the touch panel of the terminal, and the like.

The "second signature data" mentioned in the embodiment of the present invention refers to the data related to the signature detected by the stylus, for example, during the process of the user inputting the handwritten signature through the stylus, the pressure information of the user on the stylus and the movement track information of the stylus Wait.

The "time relationship" mentioned in the embodiment of the present invention refers to the detection time relationship between the "first signature data" and the "second signature data". For example, when the sampling time and sampling frequency of the touch panel and the stylus are kept synchronized, the first signature data and the second signature data corresponding to the same sampling time are corresponding.

The "spatial relationship" mentioned in the embodiment of the present invention refers to the spatial position relationship of the points corresponding to the "first signature data" and the "second signature data". It can be understood that when the pen end of the stylus is in contact with the touch panel, in the same coordinate system, the position of the pen end of the stylus is the same as the position of the contact point.

The "feature points" mentioned in the embodiments of the present invention refer to representative points in the image of the user's handwritten signature. Taking the user's handwritten signature as his Chinese name as an example, the user's surname and first name are composed of strokes. Different strokes may be discontinuous. Each user's writing habits and writing size are different. However, the strokes of each "word" in the signature are fixed. Therefore, the starting point of each stroke of the user's handwritten signature can be selected as the feature point of the user's handwritten signature. Wherein, the starting points of each stroke are embodied as discontinuous contact points detected by the touch panel.

Further, the "signature feature points" mentioned in the embodiments of the present invention refer to some representative feature points extracted from the feature points corresponding to the first signature data and the feature points corresponding to the second signature data. The point where the stylus is in contact with the touch panel is the first feature point, and the point where the stylus is outside the touch panel is the second feature point. For example, the "signature feature point" includes one or more of the first contact point, the last contact point, the discontinuous contact point, and the contact point with large curvature change between the stylus and the touch panel. The "signature feature point" also includes the point where the stylus is farthest from the touch panel in the stylus movement trajectory corresponding to the two discontinuous contact points.

Those skilled in the art can understand that, each time the stylus is lifted, the farthest distance between the stylus and the touch panel can reflect the writing habits of different users to a certain extent. For example, in the process of inputting a handwritten signature, the user needs to lift the stylus to move away from the touch panel when inputting discontinuous strokes. The distance between the two strokes, the farthest point of the stylus driven by different users from the touch panel is different.

The "security level" mentioned in the embodiment of the present invention refers to the security situation of the environment where the signature authentication system is located. For example, it is relatively safe for users to perform signature authentication in environments such as home or in a car. In a more specific example, the user needs to enter a handwritten signature on the touch panel of his personal computer to enable usage rights. When a user holds a personal computer at home or in his car, compared with other public places, the environment in the home or in the car is not easily invaded by attackers, so the security level is relatively high. Specifically, the security levels of different environments where the signature authentication system is located can be distinguished by "first", "second", "third", etc. Among them, "first" can be set as the highest security level, and the level is decreased in turn. For example, the home or car is the "first security level", the office is the "second security level", and the outdoor is the "third security level".

Further, in a relatively secure environment, where the possibility of intrusion by an attacker is low, a relatively low matching rate threshold can be set to better meet the needs of users. Specifically, different matching rate thresholds can be preset according to different security levels. For example, in the first security level, the matching rate threshold is preset to 60%. At the second security level, the matching rate threshold is preset to 70%. At the third security level, the matching rate threshold is preset to 80%. It can be understood that, the specific security level division method and the setting of the matching rate threshold can be adjusted as needed, which will not be repeated here.

In addition, in the description of this application, unless otherwise stated, "first", "second", "third", etc. are only used to distinguish different data, signature feature points or security levels, and should not be construed as A specific definition of data, signature feature points, or security level.

FIG. 1 is a schematic diagram of the architecture of a signature authentication system provided by an embodiment of the present invention. As shown in FIG. 1 , it includes a terminal 100 and a stylus 200 . The terminal 100 includes a touch panel. The user uses the stylus 200 to input a handwritten signature on the touch panel of the terminal 100, and the terminal 100 detects the relevant data of the handwritten signature such as the signature image information and the pressure information of the stylus 200 on the terminal 100; Information and data related to handwritten signatures, such as pressure information on the stylus pen 200 by the user, are sent to the terminal 100 . The terminal 100 detects the matching rate between the relevant data of the handwritten signature input by the user and the signature template data by the terminal 100 and the stylus 200. When the matching rate is not lower than the preset matching rate threshold, the terminal 100 confirms the authentication of the handwritten signature input by the user. pass.

In one example, after the handwritten signature input by the user is authenticated, the terminal 100 may allow the user to continue to access the relevant authority of the corresponding function of the terminal 100 .

As above, the relevant data of the handwritten signature input by the user may include: image information of the signature detected by the terminal 100, and pressure information of the contact point between the stylus 200 and the touch panel. and the pressure information of the user on the writing pen 200 and the movement track information of the writing pen 200 detected by the stylus pen 200 during the user's input of the handwritten signature.

Wherein, to simplify the description, the data related to the handwritten signature detected by the terminal 100 is classified as the first signature data. Data related to the handwritten signature detected by the stylus 200 is classified as second signature data. The stylus 200 sends the detected second signature data to the terminal 100 through the communication link 300 .

In the signature authentication system provided by the embodiment of the present invention, when a user uses a stylus to input a handwritten signature, the terminal detects the first signature data, and at the same time, the stylus detects the second signature data and sends it to the terminal. The terminal determines whether the handwritten signature input by the user has passed the authentication according to the first signature data, the second signature data and the pre-stored signature template data.

It can be understood that, before the user performs signature verification, the user pre-inputs a handwritten signature as a template for comparison and matching. The signature template data is data related to the handwritten signature detected by the terminal 100 and the stylus 200 when the user pre-inputs the handwritten signature. The terminal 100 stores the signature template data in the memory, and calls the signature template data stored in the memory during the authentication process of the user's input of a handwritten signature.

Specifically, when the terminal 100 compares and matches the relevant data of the handwritten signature detected by the terminal 100 and the stylus 200 with the signature template data, the processor of the terminal 100 can perform feature point data extraction on the relevant data of the handwritten signature to facilitate comparison. It can be understood that the signature template data also corresponds to the data of the relevant signature feature points.

Understandably, the speed at which a user enters a handwritten signature may vary each time. For example, it took 1S for the user to input the handwritten signature last time, and it may take 0.8S to input the handwritten signature next time. However, each user's handwritten signature has its comparable properties, for example, the signature images corresponding to different sub-signatures of the user are similar. Therefore, the handwritten signatures are compared through the data of the feature points.

In one example, the processor of the terminal 100 may extract the first contact point, the last contact point, the discontinuous contact point, the contact point with large curvature change, etc. as the first signature feature point. Data such as the contact point coordinates corresponding to the signature feature point, the pressure of the stylus on the touch panel, the coordinates of the stylus, and the pressure of the user on the stylus are extracted as the data of the first signature feature point. In addition, the processor of the terminal 100 may also use the point where the stylus is located outside the touch panel as the signature feature point. For example, the terminal 100 extracts the point at which the stylus is the farthest from the touch panel within the sampling time interval corresponding to the two discontinuous contact points as the second signature feature point. The coordinates of the stylus corresponding to the signature feature point, the user's pressure on the stylus and other data are extracted as the data of the second signature feature point.

The user inputs a handwritten signature on the touch panel of the terminal 100 through the writing pen 200, and the terminal 100 displays the signature image through the display panel. In addition, when the terminal 100 determines that the handwritten signature input by the user has passed the authentication, the display panel is instructed to display a prompt message that the authentication has passed.

As shown in FIG. 1 , the stylus 200 and the terminal 100 can implement information interaction through the communication link 300 . Wherein, the communication link 300 here may be one or more of a WiFi network, a USB interface, a Bluetooth connection, or an infrared connection.

It should be noted that the information exchange between the stylus 200 and the terminal 100 is performed. It includes: the stylus 200 sends relevant data of the handwritten signature detected by the stylus 200 to the terminal 100 through the communication link 300 , and/or the terminal 100 sends the control of the sampling time and sampling frequency of the stylus 200 to the stylus 200 through the communication link 300 information.

Specifically, the touch panel can detect the coordinate information of the contact point between the stylus 200 and the touch panel. The pressure information of the stylus 200 on the touch panel at the contact point can be detected by integrating a pressure sensor on the touch panel.

Specifically, the stylus 200 can detect the movement track information of the stylus 200 by integrating an acceleration sensor, a magnetic field strength sensor, an angular velocity sensor, and the like. The stylus 200 can detect the pressure information of the user on the stylus 200 through the pressure sensor.

It can be understood that the preset matching rate threshold can be adjusted according to actual needs. The matching rate threshold may be set according to the security level. The matching rate threshold can also be set directly. In a possible example, the terminal 100 may determine the environment where the terminal 100 is located by detecting the network to which the terminal 100 is connected. Further determine the corresponding security level and matching rate threshold.

It can be understood that the pressure information of the user on the stylus detected by the stylus reflects the strength of the user's holding the pen. The relevant data of the handwritten signature input by the user may further include: pressure area and/or pressure shape information of the stylus detected by the stylus 200 under the pressure of the user. Wherein, the pressed area and/or the pressed shape of the stylus under the user's pressure reflects the user's posture of holding the stylus (stylus). For example, the user g1 is accustomed to using the thumb and index finger to hold the pen, by pre-saving the pressure information on the stylus pen and the pressure area and/or the pressure shape of the stylus pen when the user g1 uses the thumb and index finger to hold the pen, so that the When g1 enters the handwritten signature again for authentication, it is compared with the pre-stored user g1's pen-holding strength and pen-holding posture.

Specifically, the user's pen-holding posture may be obtained through a pressure sensor or a combined use of a touch sensor with reference to the above-mentioned detection method of the user's pen-holding strength.

It can be understood that the relevant data of the handwritten signature input by the user may further include: the acceleration of the movement of the stylus detected by the stylus 200 . For example, the acceleration at the pen end of the stylus.

Specifically, the acceleration of the pen end of the stylus can be obtained by the above acceleration sensor. It can also be calculated from the motion trajectory of the stylus.

It can be understood that the relevant data of the handwritten signature input by the user may further include: distance information between the pressed area of the stylus 200 and the end of the stylus. The distance between the pressed area of the stylus and the end of the stylus reflects different users' habit of holding the pen. For example, some users like to hold the middle of the pen to write. Some users like to hold the upper end of the pen to write and so on.

In other implementation manners of this embodiment of the present invention, other users may input the security level or matching rate threshold of the environment in which the terminal 100 is located. In a specific application scenario, for example, when user C handles related business in a bank, he needs to input a handwritten signature for identity authentication. At this time, other users are bank staff D, and bank staff D can input the input to the terminal 100 according to actual needs. The matching rate threshold of user C when performing handwritten signature authentication.

In other embodiments of the present invention, the stylus 200 can be integrated on the terminal 100. For example, the terminal 100 is provided with a slot, and the stylus 200 can be inserted into the terminal 100. When the user signs, the stylus 100 is pulled out and used. To simplify the description, the embodiment of the present invention only takes the stylus 200 and the terminal 100 as an example for description.

In other embodiments of the present invention, the terminal 100 may be a smart phone with a touch screen or a terminal with a touch screen. In addition, the touch screen/touch panel can be separated from the terminal, and the touch screen can be integrated separately. In this case, the touch screen can also be called a handwriting pad. The signature authentication system will include a touch screen (handwriting pad), a terminal and a stylus. Among them, the touch screen is used to receive the user's handwritten signature and detect the information of the signature image, and a pressure sensor is integrated on the touch screen to detect the pressure information of the stylus. The touch screen records the relevant data of the handwritten signature and sends it to the terminal. The embodiments of the present invention are only described by taking the integration of the touch screen and the terminal as an example.

The signature data detected by the embodiment of the present invention includes image information of the signature detected by the terminal and pressure information of the stylus on the terminal, as well as the movement track information of the stylus detected by the stylus when the user uses the stylus to input the signature, and the pressure of the user on the stylus. information. In the signature authentication system provided by the embodiment of the present invention, in the process of the user signing with a stylus, more feature data of the user's signature is extracted through the stylus at the same time, and compared and matched, so that the attacker can imitate the user's handwriting while imitating the user's handwriting. It increases the difficulty for attackers to imitate the signature data, and greatly improves the security of the signature authentication system.

Correspondingly, an embodiment of the present invention further provides a terminal for implementing the system provided in the foregoing embodiments. As shown in FIG. 2 , the terminal includes: a display screen 110 , a sensor 120 , an I/O subsystem 130 , a processor 140 , a memory 150 , a communication unit 160 , a power supply 170 and other components. Each component of the terminal 100 will be described in detail below with reference to FIG. 2 :

The display screen 110 is used for accepting the user's input of a handwritten signature, and is also used for displaying an image of the handwritten signature input by the user or displaying prompt information of the verification result of the handwritten signature input by the user and various menus of the terminal 100 . The specific display screen 110 may include a touch panel 111 and a display panel 112 .

The touch panel 111, also referred to as a touch screen, a touch sensitive screen, etc., may collect contact or non-contact operations by a user on or near it. For example, the user operates on or near the touch panel 111 using any suitable object such as a stylus (stylus). Optionally, the touch panel 111 may include two parts, a touch detection device and a touch controller. Wherein, the touch detection device detects the touch orientation and posture of the stylus, detects the signal brought by the touch operation, and transmits the signal to the touch controller. The touch controller receives touch information from the touch detection device and converts it into information that the processor 140 can process. In addition, the touch controller can receive commands from the processor 140 and execute them.

In one example, the touch controller converts the touch orientation of the contact point of the stylus and the touch panel 111 detected by the touch detection device into coordinate information of the contact point, and sends the coordinate information of the contact point to the processor 140 .

Further, the touch panel 111 can cover the display panel 112, and the user can operate on or near the touch panel 111 covered on the display panel 112 according to the content displayed on the display panel 112, and the touch panel 111 detects the operation on or near it Then, it is transmitted to the processor 140 through the I/O subsystem 130 to determine the user input, and then the processor 140 provides corresponding visual output on the display panel 112 through the I/O subsystem 130 according to the user's input. Although in FIG. 2, the touch panel 111 and the display panel 112 are used as two independent components to realize the input and input functions of the terminal 100, in some embodiments, the touch panel 111 and the display panel 112 may be integrated to realize Input and output functions of the terminal 100 .

The I/O subsystem 130 is used to control input and output external devices, and may include a display controller 131 , a sensor controller 132 , and other input device controllers 133 . The display controller 131 receives signals from the display screen 110 and/or sends signals to the display screen 110 . After the display screen 110 detects the handwritten signature information input by the user, the display controller 131 converts the detected handwritten signature information input by the user into interaction with the user interface objects displayed on the display screen 110 . For example, the display controller 131 converts the handwritten signature information input by the user into a handwritten signature image displayed on the display panel 112 to realize human-computer interaction. Sensor controller 132 may receive signals from and/or send signals to one or more sensors 120 .

The terminal 100 may also include at least one sensor 120 , such as a pressure sensor 121 and other sensors 122 . Specifically, the pressure sensor 121 is used to detect pressure information received by the terminal 100 . Further, the pressure sensor 121 can be integrated in the display screen 110 to detect the pressure information of the stylus on the touch panel 111 and send it to the processor 140 through the sensor controller 132 . Specifically, the pressure sensor 121 is disposed between the touch panel 111 and the display panel 112, or the pressure sensor 121 is covered on the touch panel 111, so that the pressure sensor 121 detects the pressure information of the stylus on the touch panel 111.

The coordinate information of the contact point detected by the touch panel 111 and the pressure information of the stylus on the touch panel 111 detected by the pressure sensor 121 may be unified into the first signature data detected by the terminal 100 .

The processor 140 is the control center of the terminal 100, using various interfaces and lines to connect various parts of the entire terminal, by running or executing the software programs and/or modules stored in the memory 150, and calling the data stored in the memory 150, Various functions of the terminal 100 are executed and data is processed, thereby overall monitoring of the terminal 100 is performed. Optionally, the processor 140 may include one or more processing units. Preferably, the processor 140 may integrate an application processor and a modem processor, wherein the application processor mainly handles the operating system, user interface, and application programs, and the like, and the modem processor mainly handles wireless communication. It can be understood that, the above-mentioned modulation and demodulation processor may not be integrated into the processor 140.

In one example, during the user inputting a handwritten signature, the display controller 131 and the sensor controller 132 send the detected first signature data to the application processor. At the same time, the stylus 200 detects the second signature data and sends it to the terminal 100 . The second signature data sent by the stylus 200 is received by the modem processor and sent to the application processor. By running the software program in the memory 150 and calling the signature template data in the memory 150, the application processor judges whether the handwritten signature input by the user passes the authentication according to the first signature data and the second signature data of the handwritten signature. The application processor matches and compares the first signature data and the second signature data with the signature template data to obtain a corresponding matching rate. When the matching ratio is not lower than the preset matching ratio threshold, the application processor determines that the signature verification has passed, and instructs the display screen 110 to display a prompt message that the signature verification has passed.

The communication unit 160 is used to realize the information interaction between the terminal 100 and the external network or device. A wireless communication module and/or communication interface may be included. The wireless communication module can be used for signal reception and transmission in the process of sending and receiving information, for example, a radio frequency circuit or a WiFi module. The communication interface can be used to directly connect with external devices, so as to realize the exchange of information between the terminal 100 and the external devices. For example, the USB interface. In addition, the communication unit 160 may further include components such as an infrared module, a Bluetooth module, etc., which can realize information interaction between the terminal 100 and an external network or device, which is not specifically limited herein.

The terminal 100 also includes a power supply 170 (such as a battery) for supplying power to various components. Preferably, the power supply 170 can be logically connected to the processor 140 through a power management system, so as to manage charging, discharging, and power consumption functions through the power management system.

The terminal 100 may further include other input devices 180 , which are connected to the other input device controllers 133 of the I/O subsystem 130 and perform information interaction with the processor 140 under the control of the other device input controllers 133 . I won't go into details here.

In a specific example, when the user uses the stylus 200 to input a handwritten signature on the display screen 110 of the terminal 100, the touch detection device of the touch panel 111 detects the orientation signal of the contact point between the stylus 200 and the touch panel 111, and the touch panel 111 The touch controller converts the orientation signal of the contact point into coordinate information, and sends it to the processor 140 through the display controller 131 . The pressure sensor 121 detects the pressure information of the stylus 200 on the touch panel 111 at the above-mentioned contact point, and sends it to the processor 140 through the sensor controller 132 . It can be understood that the coordinate information of the contact point and the pressure information of the contact point can be recorded as the first signature data. In addition, after the display screen 110 detects the handwritten signature input by the user, the display controller 131 converts the detected handwritten signature input by the user into a signature image that can be displayed on the display screen 110 for the user to view.

The terminal 100 receives the second signature data detected by the stylus 200 through the communication unit 160 . Wherein, the second signature data includes: when the user inputs the above-mentioned handwritten signature through the stylus 200, the motion trajectory information of the stylus detected by the stylus 200, the acceleration of the pen end of the stylus, the pressure area of the stylus under the pressure of the user and/or the pressure of the stylus. related information such as the pressure shape information and the pressure information of the user on the stylus 200 . The processor 140 compares and matches the first signature data and the second signature data with the signature template data pre-stored in the memory 150, and calculates a matching rate. The processor 140 compares the matching ratio calculated above with the matching ratio threshold pre-stored in the memory 150. When the matching ratio threshold calculated above is not lower than the pre-stored matching ratio threshold, the processor 140 determines that the user's handwritten signature is authenticated. pass. The processor 140 instructs the display panel 112 to display a prompt message that the user's handwritten signature is authenticated.

Specifically, the processor 140 of the terminal 100 may extract the data of the signature feature points through the first signature data and the second signature data. The data of the extracted signature feature point is matched and compared with the data of the signature feature point corresponding to the signature template, and the matching rate is calculated. The signature feature points include a first signature feature point and a second signature feature point. The data of the signature feature point includes data of the first signature feature point and data of the second signature feature point. For the extraction method of specific signature feature points and their data, please refer to the detailed introduction in FIG. 4 .

It should be noted that, before the user uses the stylus 200 to input the above-mentioned handwritten signature, the user or other users may send an instruction indicating the user's identity information to the processor 140, and the processor 140 may indicate the user's identity information according to the instruction of the user's identity information. The instructions recall the user's signature template data from memory 150 .

Specifically, the instruction indicating the user's identity information may be information such as the user's ID number, the user's job number, and the like. Among them, the signature template data of a plurality of users are pre-stored in the memory 150, and the signature template data of each user carries the identity information of the user. After receiving the instruction indicating the user's identity information, the processor 140 queries the memory 150 for the user's signature template data according to the user's identity information. The signature template data of each user carries the identity information of the user.

It can be understood that, considering the inherent difference of the handwritten signatures input by the user each time, the signature template data of each user may include multiple pieces. That is, when the user pre-inputs a handwritten signature, the user can input the handwritten signature (template) multiple times, and the terminal 100 and the stylus 200 detect the data of each handwritten signature (template) and save them one by one. In the stage where the user inputs the handwritten signature for authentication, the processor 140 compares and matches the signature data in the authentication stage detected by the terminal 100 and the stylus 200 with the multiple signature template data of the user, and selects the one with the largest matching rate as the final one. Compare the matching rate, and judge whether the user's signature authentication is passed according to the preset matching rate threshold.

It can be understood that the signature template data also includes the first signature (template) data detected by the terminal 100 and the second signature (template) data detected by the stylus 200. In addition, the signature template data may include the extracted data of the corresponding signature feature points. For the extraction method of specific signature feature points and their data, please refer to the detailed introduction in FIG. 4 .

Correspondingly, an embodiment of the present invention also provides a stylus pen, which is used to implement the system provided in the foregoing embodiments. As shown in FIG. 3 , the stylus includes: a sensor unit 210 , a communication unit 220 , a processor 230 , a memory 240 , a power supply 250 and other components. Each component of the stylus 200 will be described in detail below with reference to FIG. 3 :

The sensor unit 210 is configured to detect relevant signature data in the process of inputting a handwritten signature by the user using the stylus 200 on the touch panel 111 of the terminal 100 . Specifically, the sensor unit 210 may include an acceleration sensor 211, a magnetic field strength sensor 212, an angular velocity sensor 213, a pressure sensor 214, and other sensors 215.

In a possible implementation, the acceleration sensor 211 can be used to detect the acceleration of the pen end of the stylus 200 , the magnetic field strength sensor 212 can be used to detect the magnetic field strength of the stylus 200 , and the angular velocity sensor 213 can be used to detect the angular velocity of the stylus 200 . Further, the movement track information of the stylus 200 can be obtained according to the change information of the acceleration, the angular velocity and the magnetic field strength of the stylus 200 . The pressure sensor 214 may be used to detect the pressure information of the user on the stylus 200 .

It should be noted that other sensors 215 may include sensors such as gyroscopes, gravity sensors, WiFi positioning sensors, or infrared positioning sensors. Wherein, the acceleration sensor 211 , the magnetic field strength sensor 212 , and the angular velocity sensor 213 used for detecting the motion trajectory information of the stylus 200 can be replaced by one or more of other sensors 215 . The embodiment of the present invention does not specifically limit the sensor used for detecting the movement track data of the stylus 200 . It can be understood that the sensors or instruments used to detect the movement trajectory of the stylus should all belong to the protection scope of the embodiments of the present invention.

The sensor unit 210 can also detect the pressure area information and pressure shape information of the stylus under pressure from the user, and the distance information of the stylus pressure area from the stylus pen end, etc. through the relevant sensors. The relevant sensors here may include touch sensors. The above information can also be used as one or more of the second signature data to reflect the pen-holding habits of different users. Through the comparison of the above feature information, the attacker's imitation difficulty is increased.

The communication unit 220 is used for connecting with the foregoing communication unit 160 to realize the information interaction between the stylus 200 and the terminal 100 . The communication unit 220 may also include a communication module and/or a communication interface corresponding to the communication unit 160 . For example, the communication unit 160 includes a WiFi module 1 , the communication unit 220 includes a corresponding WiFi module 2 , and the terminal 100 and the stylus 200 establish a communication connection through the WiFi module 1 and the WiFi module 2 .

The processor 230 is configured to run or execute the software programs and/or modules stored in the memory 240 , and execute the exchange of the relevant signature data detected by the sensor unit 210 into information that the terminal 100 can process. For example, the processor 230 converts the acceleration information, magnetic field strength information and angular velocity information of the stylus 200 detected by the acceleration sensor 211, the magnetic field strength sensor 212, and the angular velocity sensor 213 into motion trajectory information of the stylus pen that can be processed by the terminal 100, and sends it to the terminal 100.

In addition, the processor 230 is further configured to control the sampling time and sampling frequency of the sensor unit 210 through the control information. It can be understood that the above-mentioned control information can also be sent by the terminal 100 to control the sampling time and sampling frequency of the stylus 200 to keep synchronization with the touch panel and the sensor of the terminal 100 .

The memory 240 is used for storing relevant software and/or modules, such as software and/or modules for executing the exchange of relevant signature data detected by the sensor unit 210 into information that can be processed by the processor 140 . It is also used to store the data detected by the sensor unit 210, and after sampling is completed, it is sent to the processor 230, so that the processor 230 converts the data detected by the sensor unit 210 into second signature data that the terminal can process.

The stylus 200 also includes a power supply 250 that powers the various components.

In a specific example, when the user uses the stylus 200 to input a handwritten signature on the touch panel 111 of the terminal 100, the stylus 200 detects the acceleration, magnetic field strength, Magnetic field strength, etc. The pressure information of the user on the stylus 200 through the pressure sensor 214 .

The stylus 200 converts the acceleration, magnetic field strength, magnetic field strength and other information of the stylus 200 into motion trajectory information of the stylus 200 through the processor 230 . The movement track information of the stylus 200 and the pressure information of the user on the stylus 200 are the second signature data. The stylus 200 also uses the processor 230 to combine the movement track information of the stylus 200, the acceleration of the stylus 200, the pressure area and/or the pressure shape of the stylus 200 under the user's pressure, and the user's pressure on the stylus 200 through the processor 230. The pressure information is extracted, packaged into a data packet carrying the corresponding time information, and sent to the terminal 100 through the communication unit 220 .

It should be noted that the stylus 200 receives the control information of sampling time and sampling frequency sent by the terminal 100 through the communication unit 220 to ensure the temporal correspondence between the first signature data and the second signature data. For example, the sampling time of the first contact point between the stylus 200 and the touch panel 111 of the terminal is 0ms, the terminal 100 sends the control information so that the sampling time of the stylus 200 is also 0ms at this time, and controls the stylus 200 and the terminal 100 The sampling frequency is 0.2ms/time. It can be understood that, in the case where the sampling time and sampling frequency of the terminal 100 and the stylus 200 are synchronized, for the attacker, while imitating the user's handwriting and imitating the pressure of the user's holding the stylus on the touch panel, he also needs to imitate the user's handwriting. It is very difficult to obtain information such as hand movements and user pressure on the stylus.

Therefore, by applying the above signature authentication system, terminal and stylus, the signature template data is added, and the sampling time and sampling frequency of the stylus and the terminal are controlled to be synchronized. The user signature feature data is compared and matched, so that the attacker can imitate the user's handwriting while imitating the user's handwriting, which increases the difficulty for the attacker to imitate the signature data, and greatly improves the security of the signature authentication system.

Correspondingly, reference may be made to FIG. 4 for a schematic diagram of a coordinate system and a signature of the signature authentication system provided by the embodiment of the present invention.

As shown in FIG. 4 , the user inputs a handwritten signature on the touch panel with a stylus by hand. The location where the stylus comes into contact with the touch panel can be referred to as the point of contact. The touch panel detects the orientation of the touch point and displays the touch point through a display panel integrated with the touch panel. For example, the display panel was originally displayed in white, but after detecting a touch point, the touch point is displayed in black.

The user drives the stylus to move on the touch panel, and all the contact points between the stylus and the touch panel form the user's signature image. In Figure 4, "Xiao Wang" is an image of the user's handwritten signature.

Wherein, when the user holds the stylus pen and writes the pen, there is a contact point with the touch panel, such as the contact point shown in FIG. 4 . Between writing different strokes or different characters, the user lifts the stylus and moves the stylus from the previous contact point to the next discontinuous contact point in the area outside the touch panel. When the user holds the stylus and lifts the stylus, the stylus will draw a movement track in the area outside the touch panel, as shown in FIG. 4 .

Therefore, the pen-down point (contact point) of the stylus can be set as the first signature feature point, and the point corresponding to the stylus-up (point other than the contact point) can be set as the second signature feature point.

During the process of the user inputting the handwritten signature, the touch panel converts the detected touch orientation of the contact point into coordinate information of the contact point. The touch panel integrates a pressure sensor for detecting the pressure information of the stylus at the contact point. At the same time, the stylus integrates relevant sensors to detect the movement track information of the stylus and the pressure information of the user on the stylus. For example, the stylus obtains the motion trajectory information of the stylus through the acceleration sensor, the magnetic field strength sensor, and the angular velocity sensor, and detects the pressure information of the user on the stylus through the pressure sensor.

Therefore, the coordinate information of the contact point detected by the touch panel and the pressure sensor integrated thereon and the pressure information of the stylus on the touch panel can be set as the first signature data, and the movement track information of the stylus detected by the stylus through the relevant sensor can be used as the first signature data. and the user's pressure information on the stylus as the second signature data.

Therefore, the data corresponding to the first signature feature point may include coordinate information of the contact point, pressure information of the stylus on the touch panel at the contact point, coordinate information of the pen end of the stylus, and pressure information of the user on the stylus. It can be understood that, if they are in the same coordinate system, the coordinate information of the contact point and the coordinate information of the pen end of the stylus are the same, and one can be selected. The data corresponding to the second signature feature point may include: coordinate information of the pen end of the stylus and pressure information of the user on the stylus. Specifically, when the stylus is lifted, the touch panel and the pressure sensor integrated thereon cannot detect the relevant information of the contact point. That is, assuming that the stylus is lifted during the time period from time T1 to time T2, there is no detected first signature data in this time period.

In a possible example, the coordinate system of the touch panel is shown as o ₁ x ₁ y ₁ z ₁ in FIG. 4 , the x-axis and y-axis of the o ₁ x ₁ y ₁ z ₁ coordinate system are in the plane where the touch panel is located, z The axis is perpendicular to the plane of the touch panel. The coordinate system of the stylus is shown in Figure 4,

o The z-axis of the ₂ x ₂ y ₂ z ₂ coordinate system is the straight line where the stylus is located, and the x-axis and y-axis are in a plane perpendicular to the stylus.

It should be noted that when the touch panel detects a contact point, the coordinate information is recorded in the o ₁ x ₁ y ₁ z ₁ coordinate system. But consider that the relative origin of the user's input signature position may be different each time. Therefore, the processor of the terminal can preprocess the received coordinate information of the contact point, and transform the data in the coordinate system o ₁ x ₁ y ₁ z ₁ into a new coordinate system. The input handwritten signature images are all for reference. For example, the new coordinate system may be the center of the user's handwritten signature as the origin, and the two midlines of the signature as the x-axis and the y-axis. The "middle line" of the signature refers to the two lines of symmetry of the signature image. Specifically, the average point of the x-coordinate can be obtained by calculating the average value of the y-coordinate of the contact points with the same x-coordinate in the o ₁ x ₁ y ₁ z ₁ coordinate system. Click to find a midpoint of the signature image. The other halfway line passes through the signature center point and is perpendicular to one halfway line.

It can be understood that the signature image input by the user each time is fixed and comparable with respect to the center point and the midpoint line of the image. Therefore, the data in the signature template is also subjected to transformation processing corresponding to the new coordinate system as described above.

The touch panel detects the coordinates of the contact point in the coordinate system o ₁ x ₁ y ₁ z ₁ . It can be understood that, in the touch panel, the z-axis coordinates of the contact points are all 0. Therefore, (a1, b1, 0) can be used to represent the coordinates of the contact point. The stylus detects the movement trajectory of the stylus in the coordinate system o ₂ x ₂ y ₂ z ₂ , and the movement trajectory of the stylus can be represented by the movement trajectory of the pen end of the stylus. The coordinates of the pen end of the stylus may be (a2, b2, c).

It should be noted that when the stylus pen is down, when the stylus pen end has a contact point with the touch panel, if they are in the same coordinate system, the coordinates of the contact point should be the same as the coordinates of the stylus pen end. During actual detection, the coordinates of the same contact point or its corresponding stylus pen end in the two coordinate systems o ₁ x ₁ y ₁ z ₁ and o ₂ x ₂ y ₂ z ₂ may be different.

The coordinate information in the o ₂ x ₂ y ₂ z ₂ coordinate system can be transformed into the coordinate system o ₁ x ₁ y ₁ z ₁ through coordinate transformation. Specifically, the coordinate transformation can use the same contact point or its corresponding stylus. Analyze the positional relationship between the two coordinate systems, and perform coordinate transformation on one of the coordinate systems.

Further, the data in the signature feature points may include multiple pieces, and the contact point is S1 as an example, for example, S1 may be the first contact point between the stylus and the touch panel. The signature feature data E corresponding to S1 includes: the coordinates of the contact point (a1, b1, 0), the pressure P1 of the stylus on the touch panel, the coordinates of the stylus (a2, b2, c), and the pressure P2 of the user on the stylus . Correspondingly, the signature feature point S1 corresponds to the signature feature data e included in the signature template book: the coordinates of the contact point (m1, n1, 0), the pressure D1 of the stylus on the touch panel, the coordinates of the stylus (m2, n2, q), the pressure D2 of the user on the stylus.

Then the matching rate of data E and data e includes (a1,b1,0) and (m1,n1,0), P1 and D1, (a2,b2,c) and (m2,n2,q), P2 and D2 The average or weighted average of the matching rates of the four sets of data. The matching ratio of the coordinates of the two points can be obtained by the matching ratio of the distances between the two coordinates from the origin, or it can be obtained by calculating the matching ratio of the corresponding coordinate values and then weighted and averaged.

In addition, the data of signature feature points may include more than one, then the matching rate of all signature feature points and signature template data can be calculated by the matching rate of data corresponding to each feature point, and then the matching rate corresponding to all signature feature points can be averaged or weighted average to get. Among them, the weighted value can be set according to actual needs.

In addition, the movement trajectory of the stylus pen end collected by the stylus and the coordinates of the contact point collected by the touch panel can be transformed into a unified coordinate system, and the transformed movement trajectory of the stylus pen end can be projected. The data of the feature points of the projected motion trajectory are extracted as the data of the signature feature points. For details, please refer to the following description:

In one example, after the coordinate system o ₂ x ₂ y ₂ z ₂ of the stylus is transformed into the coordinate system o ₁ x ₁ y ₁ z ₁ of the touch panel, the end of the stylus can be placed in the coordinate system o ₂ x ₂ y The motion path data in ₂ z ₂ are correspondingly converted into motion path data in the coordinate system o ₁ x ₁ y ₁ z ₁ . In the o ₁ x ₁ y ₁ z ₁ coordinate system, the xy plane where the touch panel is located is the first plane, and the curve formed by the contact points in the signature image is the first motion trajectory of the stylus pen end on the first plane. Project the converted (three-dimensional) motion trajectory of the stylus pen end on the plane where the touch panel is located, remove the part that overlaps with the first motion trajectory after projection, and obtain the second motion trajectory of the stylus pen end on the first plane.

Then, the above-mentioned first signature feature point is a feature point extracted from the first motion trajectory of the stylus. At this time, the coordinate information of the first signature feature point may be represented by two-dimensional coordinates in the first plane. It can be understood that, if the movement trajectory of the stylus is projected on the first plane, a new second signature feature point can be extracted from the second movement trajectory of the stylus. For example, the new second signature feature point may be a point with a large curvature change in each discontinuous curve corresponding to the second motion trajectory. Therefore, the data corresponding to the new second signature feature point are the two-dimensional coordinates of the point on the first plane and the pressure information of the user on the stylus corresponding to the point, the acceleration of the stylus pen end, and the pressure of the stylus by the user's pressure. Area and compression shape data.

It can be understood that after combining the two coordinate systems, the coordinates of the first signature feature point will coincide with the coordinates of the new second signature feature point.

In another example, after the coordinate system o ₂ x ₂ y ₂ z ₂ of the stylus is transformed into the coordinate system o ₁ x ₁ y ₁ z ₁ of the touch panel, the pen end of the stylus can be placed in the coordinate system o ₂ x ₂ The motion path data in y ₂ z ₂ are correspondingly converted into motion path data in the coordinate system o ₁ x ₁ y ₁ z ₁ . In the o ₁ x ₁ y ₁ z ₁ coordinate system, the xy plane where the touch panel is located is the first plane, and the curve formed by the contact points in the signature image is the first motion trajectory of the stylus pen end on the first plane. Let the two planes perpendicular to the first plane be the second plane and the third plane. Wherein, the second plane and the third plane are perpendicular to each other, and the second plane and the third plane and the first plane share an origin and a coordinate axis. Project the (three-dimensional) motion trajectory of the converted stylus pen end on the first plane, the second plane, and the third plane respectively, remove the part that overlaps with the first motion trajectory after the projection, and obtain the third plane of the stylus pen end in the three planes. Two motion trajectories.

Then, the above-mentioned first signature feature point is a feature point extracted from the first motion trajectory of the stylus. At this time, the coordinate information of the first signature feature point may be represented by two-dimensional coordinates in the first plane. For example, the data corresponding to the first signature feature point includes: the coordinates (m1, n1) of the contact point on the first plane, the pressure D1 of the stylus on the touch panel, and the pressure D2 of the user on the stylus. It may also include data such as the acceleration d1 of the pen end of the stylus, the pressure area S1 of the stylus, and the distance T1 of the pressure area of the stylus from the end of the stylus.

It can be understood that, if the movement trajectory of the stylus is projected on three planes, a new second signature feature point can be extracted from the second movement trajectory of the stylus. For example, the new second signature feature point may be a point with a large curvature change in each discontinuous curve corresponding to the second motion trajectory. Therefore, the data corresponding to the new second signature feature point are the two-dimensional coordinates of the point on the first plane, the two-dimensional coordinates on the second plane, or the two-dimensional coordinates on the third plane, and the corresponding user's stylus of the point. The pressure information of the stylus, the acceleration of the pen end of the stylus, and the pressure area and pressure shape of the stylus under the pressure of the user.

For example, the data corresponding to the new second signature feature point includes: the coordinates of the feature point on the first plane (m2, n2) or the coordinates of the feature point on the second plane (m3, q1) or the feature point on the second plane. The coordinates of the plane (n3, q2), the pressure D2 of the stylus on the touch panel, and the pressure D4 of the user on the stylus. It may also include data such as the acceleration d2 of the pen end of the stylus, the pressure area S2 of the stylus, and the distance T2 of the pressure area of the stylus from the end of the stylus. The feature data of projection points in different planes can be extracted and compared respectively.

Specifically, if the signature authentication comparison scheme of coordinate system transformation and projection of the motion trajectory of the stylus is adopted, when the signature template data is pre-stored, the detected signature template data pre-input by the user is also transformed correspondingly, and the corresponding signature is raised. The feature points and signature feature data are saved as signature template data.

In the embodiment of the present invention, the two coordinate systems of the stylus pen and the touch panel of the terminal can also be transformed, and the movement trajectory of the stylus pen is projected on the plane where the touch panel is located, so as to avoid the possible It will be the case that the coordinate data of the same feature point in the two coordinate systems are matched and compared. The embodiment of the present invention also projects the movement trajectory of the stylus on two planes perpendicular to the plane where the touch panel is located, simplifies the comparison of three-dimensional coordinates into two-dimensional coordinate comparison, and simplifies the complexity of comparing and matching signature data. It should be noted that FIG. 4 is only a more intuitive schematic form of the signature authentication system, and is not used as any limitation to the solution of the embodiment of the present invention.

The following describes the signature authentication method provided by the embodiment of the present invention in detail with reference to FIG. 5 . FIG. 5 is a signaling interaction diagram of a signature authentication method provided by the embodiment of the present invention. In the embodiment of the present invention, the implementation subject is a terminal. As shown in Figure 5, this embodiment specifically includes the following steps:

Step S101, the touch panel of the terminal detects the handwritten signature input by the user through the stylus.

Step S102, the terminal sends control information to the stylus, so as to control the sampling time and sampling frequency of the stylus to keep synchronization with the terminal.

The terminal sends control information to the stylus through the communication unit 1 .

The sampling time and sampling frequency of the terminal and the stylus are synchronized with the terminal, so that the attacker can imitate the user's hand movements while imitating the user's handwriting, which increases the difficulty for the attacker to imitate the signature data and greatly improves the signature. Authentication system security.

It should be noted that the user's handwriting here refers to the image information of the user's signature, and specifically, the handwriting may refer to the coordinate information of each point in the signature image. In addition, the handwriting may also include pressure information of the stylus against the touch panel at each point in the signature image. Wherein, each point in the signature image corresponds to a point of contact between the stylus and the touch panel.

It should be noted that the user's hand motion here refers to the movement track information when the user drives the stylus to move during the process of the user using the stylus to input the signature. In addition, the hand motion may also include information on the user's pressure on the stylus, the pressure area of the stylus under pressure from the user, the shape information of the pressure area, and the distance information between the pressure area and the end of the stylus.

It can be understood that the user's handwriting and the user's hand movements represent the feature information in the user's signature input process. According to the feature information listed above, determining the authentication result of the user's input signature can improve the security of the signature authentication system. and reliability.

Step S103a, the touch panel collects the coordinate information of the contact point between the stylus and the touch panel, and the pressure sensor collects the pressure information of the stylus on the touch panel at the contact point.

Among them, the contact point between the stylus and the touch panel constitutes a signature image.

Step S103b, the sensor unit of the stylus collects the movement track information of the stylus and the pressure information of the user on the stylus.

Among them, the acceleration, magnetic field strength, magnetic field strength and other information of the stylus can be detected by an acceleration sensor, a magnetic field strength sensor, and an angular velocity sensor. The pressure information of the user on the stylus through the pressure sensor.

Further, other sensors can also be heard to detect the pressure area of the stylus under pressure from the user, the shape information of the pressure area, and the distance information of the pressure area from the pen end of the stylus. Other sensors here may also include pressure sensors and the like.

In step S104a, the processor of the terminal converts the data collected in step S103a into first signature data.

The processor of the terminal corresponds the data detected by the touch panel and the pressure sensor one by one according to the collection time, that is, one collection time corresponds to the coordinate information of a contact point and the pressure information of the stylus on the touch panel at the contact point.

In step S104b, the processor of the stylus converts the data collected in step S103b into second signature data.

The processor of the stylus converts information such as acceleration, magnetic field strength, and magnetic field strength of the stylus into motion track information of the stylus.

The processor of the stylus associates the movement track information of the stylus with the pressure information of the user on the stylus according to the collection time, that is, the coordinate information corresponding to a stylus at one collection time and the pressure of the user on the stylus at the collection time. information.

In addition, in the case that the data collected in step S103b also includes other information, the data corresponding to each collection time mentioned above is correspondingly increased.

Step S105, the stylus sends the second signature data to the terminal.

The stylus sends the second signature data to the terminal through the communication unit 2 .

Step S106, the processor of the terminal obtains the data of the first signature feature point and the data of the second signature feature point according to the first signature data and the second signature data.

The signature corresponds to the first signature feature point and the second signature feature point. The first signature feature point includes at least one point in the set of contact points, and the second signature feature point includes at least one point in the set of points in the movement trajectory of the stylus in the area outside the touch panel.

The data corresponding to the first signature feature point includes: the coordinate information of the contact point corresponding to the first signature feature point, the pressure information of the stylus on the touch panel at the contact point corresponding to the first signature feature point, and the pressure information at the contact point corresponding to the first signature feature point. When the sampling time is the same, the position information of the stylus and the pressure information of the user on the stylus are obtained; wherein, the position information of the stylus is obtained from the track information of the stylus.

The data corresponding to the second signature feature point includes: the position information of the stylus corresponding to the second signature feature point and the pressure information of the user on the stylus.

In addition, in the case where the data collected in step S103b also includes other information, the data corresponding to the second signature feature point further includes: when the user signs on the touch panel with the stylus detected by the stylus, the stylus is affected by the user's pressure. The pressure area information and the shape information of the pressure area, and the distance information from the pressure area of the stylus to the end of the stylus.

Specifically, the first signature feature point specifically includes: one or more points among the first contact point, the last contact point, a discontinuous contact point, or a contact point with a large curvature change.

Specifically, the second signature feature point specifically includes one or more of the following points: the point with the largest curvature in the curve corresponding to the motion trajectory of each discontinuous stylus in the area outside the touch panel, or the point outside the touch panel The point farthest from the touch panel in the curve corresponding to the motion trajectory of each discontinuous stylus in the area.

In addition, a unified coordinate system transformation can be performed on the movement track of the stylus pen end and the coordinates of the contact point collected by the touch panel, and the transformed movement track of the stylus pen end can be projected. The feature points of the projected motion trajectory and the data of the signature feature points are extracted as the data of the new signature feature points. For details, reference may be made to the description in FIG. 4 , which will not be repeated here.

Step S107, the processor of the terminal compares the data of the first signature feature point and the data of the second signature feature point with the pre-stored signature template data to obtain a matching rate.

It should be noted that the signature template data is data related to the pre-input handwritten signature detected by the terminal and the stylus when the handwritten signature is pre-input before the user inputs the hand-written signature for authentication. The terminal stores the signature template data in the memory, and calls the signature template data stored in the memory during the authentication process of the user's input of a handwritten signature.

The pre-input handwritten signature refers to saving some template data before the user performs signature authentication, as a basis for comparison during signature authentication.

Step S108, the processor of the terminal compares the matching rate with a pre-stored matching ratio threshold, and when the matching ratio is not lower than the pre-stored matching ratio threshold, instructs the display panel to display a prompt message that the user enters the handwritten signature authentication.

The matching rate threshold can be preset by the terminal and directly called from the memory when the user inputs the signature for authentication.

In addition, the matching rate threshold can also be adjusted according to the actual environment of the terminal. At this time, the terminal can judge the environment in which it is located through the network to which its communication unit 1 is connected. According to the environment where the terminal is located, the security level of the environment where the terminal is located is determined, and the matching rate threshold under the security level is called from the memory. Wherein, in the memory of the terminal, a list of environments corresponding to different networks, a list of security levels corresponding to different environments, and a list of matching rate thresholds corresponding to different security levels are stored. Further, a list of matching rate thresholds corresponding to different networks or environments can be directly stored. Users can directly call their corresponding matching rate thresholds through the network or environment.

In the signature authentication method, terminal, stylus, and system provided by the embodiments of the present invention, the terminal and the stylus simultaneously detect the relevant data of the signature, compare and match the relevant data of the signature with the pre-stored signature template data, and determine whether the signature is authenticated according to the matching rate. pass.

In this embodiment of the present invention, when a user uses a stylus to input a handwritten signature on the touch panel of a terminal, the stylus is used to extract more user signature feature data and compare and match, so that the attacker can imitate the user's handwriting while imitating the user's handwriting. It increases the difficulty for attackers to imitate the user's signature information, and greatly improves the security of the signature authentication system.

The embodiment of the present invention can also set different matching rate thresholds according to the environment where the terminal is located, which has a good application prospect. At the same time, the embodiment of the present invention proposes that the user can pre-store multiple signature templates in advance, which can reduce the authentication failure rate caused by human factors, and enable the user to input a signature with higher flexibility.

In the embodiment of the present invention, the two coordinate systems of the stylus pen and the touch panel of the terminal can also be transformed, and the movement trajectory of the stylus pen is projected on the plane where the touch panel is located, so as to avoid the possible It will be the case that the coordinate data of the same feature point in the two coordinate systems are matched and compared. The embodiment of the present invention also projects the movement trajectory of the stylus on two planes perpendicular to the plane where the touch panel is located, simplifies the comparison of three-dimensional coordinates into two-dimensional coordinate comparison, and simplifies the complexity of comparing and matching signature data.

Professionals should be further aware that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. Interchangeability, the above description has generally described the components and steps of each example in terms of function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of the present invention.

Those of ordinary skill in the art can understand that all or part of the steps in the method of implementing the above embodiments can be completed by instructing the processor through a program, and the program can be stored in a computer-readable storage medium, and the storage medium is non-transitory ( English: non-transitory) media, such as random access memory, read only memory, flash memory, hard disk, solid state disk, magnetic tape (English: magnetic tape), floppy disk (English: floppy disk), optical disc (English: optical disc) and any combination thereof.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. Substitutions should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims (20)

1. A signature authentication method, characterized in that the method comprises: When the user signs on the touch panel of the terminal with the stylus, the terminal detects the first signature data, and the first signature data includes the coordinate information of the contact point between the stylus and the touch panel and the location of the contact point. pressure information of the stylus on the touch panel; and, the terminal receives second signature data sent by the stylus, the second signature data includes the stylus detected when the user touches the touch panel with the stylus The movement track information of the stylus and the pressure information of the user on the stylus when signing on the panel; The signature corresponds to a first signature feature point and a second signature feature point, the first signature feature point includes at least one point in the set composed of the contact points, and the second signature feature point includes the stylus in the at least one point in the set of points in the motion trajectory of the area outside the touch panel; Extracting data corresponding to the first signature feature point and the second signature feature point from the first signature data and the second signature data; Matching and comparing the data corresponding to the first signature feature point and the second signature feature point with the data of each feature point in the signature template data to obtain a matching rate; When the matching rate is not lower than a preset matching rate threshold, the signature authentication is passed. 2. The method of claim 1, wherein the sampling time and sampling frequency of the first signature data and the second signature data are kept synchronized. 3 . The method according to claim 1 , wherein the data corresponding to the first signature feature point comprises: coordinate information of the contact point corresponding to the first signature feature point, information corresponding to the first signature feature point The pressure information of the stylus on the touch panel at the contact point of the stylus and the position information of the stylus and the pressure information of the user on the stylus when the sampling time of the first signature feature point is the same; Wherein, the position information of the stylus is obtained from the movement track information of the stylus. 4 . The method of claim 3 , wherein the data corresponding to the second signature feature point comprises: position information of the stylus corresponding to the second signature feature point and user pressure on the stylus pen. 5 . information. 5. The method according to claim 1 or 4, wherein the second signature data further comprises: acceleration of the stylus detected by the stylus when the user signs the touch panel with the stylus , the pressure area information and the shape information of the pressure area of the stylus pen subjected to user pressure, and the distance information of the stylus pen pressure area from the pen end of the stylus pen. 6. The method according to claim 1, wherein the first signature feature point specifically comprises one or more of the following points: a first contact point, a last contact point, a discontinuous contact point or contact points with large curvature changes. 7 . The method of claim 1 , wherein the second signature feature point specifically includes one or more of the following points: each segment of the handwriting that is discontinuous in an area outside the touch panel. 8 . The point with the largest curvature in the curve corresponding to the movement track of the pen, or the point farthest from the touch panel in the curve corresponding to the movement track of the stylus pen for each discontinuous segment in the area outside the touch panel. 8. The method according to claim 1 or 2, wherein the matching and comparison of the first signature data and the second signature data with pre-stored signature template data to obtain a matching rate, comprising: extracting a first signature feature point from the contact point; Projecting the motion trajectory of the pen end of the stylus on the first plane where the touch panel is located to obtain the first motion trajectory of the stylus pen end; placing the motion trajectory of the stylus pen end on a second plane perpendicular to the first plane , the third plane is projected to obtain the second motion track and the third motion track of the pen end of the stylus, and the second plane is perpendicular to the third plane; extracting a second signature feature point from at least one of the first motion trajectory, the second motion trajectory and the third motion trajectory; Extracting data corresponding to the first signature feature point and the second signature feature point from the first signature data and the second signature data; The data corresponding to the first signature feature point and the second signature feature point are matched and compared with the data of each feature point in the signature template data to obtain a matching rate. 9 . The method of claim 1 , wherein the matching rate threshold is preset according to an environment where the terminal is located. 10 . 10. A signature authentication method, wherein the method comprises: When the user signs on the touch panel of the terminal with a stylus, the stylus detects second signature data, and the second signature data includes the movement track information of the stylus and the pressure information of the user on the stylus ; The stylus sends the second signature data to the terminal, so that the terminal extracts the data corresponding to the first signature feature point and the second signature feature point from the first signature data and the second signature data, The data corresponding to the first signature feature point and the second signature feature point are matched and compared with the data of each feature point in the signature template data to determine whether the signature authentication is passed, and the first signature data includes a stylus and a stylus. The coordinate information of the contact point of the touch panel and the pressure information of the stylus on the touch panel at the contact point, the signature corresponds to the first signature feature point and the second signature feature point, the first signature A signature feature point includes at least one point in the set consisting of the contact points, and the second signature feature point includes at least one point in the set of points in the movement trajectory of the stylus in the area outside the touch panel one point. 11. The method of claim 10, wherein the second signature data further comprises: acceleration of the stylus detected by the stylus when the user signs the touch panel with the stylus, The pressure area information and the shape information of the pressure area of the stylus pen subjected to the user's pressure, and the distance information of the pressure area of the stylus pen from the pen end of the stylus pen. 12. The method according to claim 10 or 11, wherein the sampling time and sampling frequency of the first signature data and the second signature data are kept synchronized. 13. A terminal, characterized in that the terminal comprises: a touch panel, a display panel, a sensor, a processor, a memory, and a communication unit; The touch panel is used for receiving a signature input by a user through a stylus; the display panel for displaying the image of the signature; The touch panel is also used to detect the coordinate information of the contact point between the stylus and the touch panel; The sensor is used to detect the pressure information of the stylus on the touch panel at the contact point; the coordinate information of the contact point and the pressure information of the stylus on the touch panel at the contact point form a first signature data; The communication unit is configured to establish a communication connection with the stylus, and receive second signature data sent by the stylus, where the second signature data includes the stylus detected when the user touches the touch with the stylus. The movement track information of the stylus and the pressure information of the user on the stylus when signing on the panel; the memory for storing a preset matching rate threshold; The signature corresponds to a first signature feature point and a second signature feature point, the first signature feature point includes at least one point in the set composed of the contact points, and the second signature feature point includes the stylus in the at least one point in the set of points in the motion trajectory of the area outside the touch panel; the processor is configured to extract the first signature from the first signature data and the second signature data The data corresponding to the feature point and the second signature feature point; match and compare the data corresponding to the first signature feature point and the second signature feature point with the data of each feature point in the signature template data to obtain a matching rate; when When the matching rate is not lower than the preset matching rate threshold, instructing the display panel to display the prompt information that the signature authentication is passed; The display panel is also used for displaying prompt information that the signature verification is passed. 14. The terminal according to claim 13, wherein the processor is further configured to send control information on the sampling time and sampling frequency of the stylus to the stylus, so as to control the first The signature data is synchronized with the sampling time and sampling frequency of the second signature data. 15. The terminal according to claim 13 or 14, wherein the processor is specifically configured to extract the first signature feature point from the contact point; the movement track of the stylus pen end is displayed on the touch panel Project the first plane where it is located to obtain the first motion trajectory of the pen end of the stylus; project the motion trajectory of the pen end of the stylus on a second plane and a third plane perpendicular to the first plane to obtain the stylus pen The second motion track and the third motion track of the pen end, the second plane is perpendicular to the third plane; extracted from at least one motion track of the first motion track, the second motion track and the third motion track the second signature feature point; extract the data corresponding to the first signature feature point and the second signature feature point from the first signature data and the second signature data; combine the first signature feature point and the second signature feature point The data corresponding to the signature feature points is matched and compared with the data of each feature point in the signature template data to obtain a matching rate. 16 . The terminal according to claim 13 , wherein the processor is further configured to determine an environment where the terminal is located according to a network to which the communication unit is connected, and preset the environment according to the environment where the terminal is located. 17 . Match rate threshold. 17. A stylus, characterized in that the stylus comprises: a sensor unit, a processor, and a communication unit; the sensor unit, configured to detect the movement track information of the stylus and the pressure information of the user on the stylus when the user signs on the touch panel of the terminal with the stylus; The processor is configured to convert the motion trajectory information of the stylus pen and the pressure information of the user on the stylus pen into second signature data that can be processed by the terminal, and instruct the communication unit to send to the terminal ; The signature corresponds to a first signature feature point and a second signature feature point, the first signature feature point includes at least one point in a set of contact points, and the second signature feature point includes the stylus in the at least one point in the set of points in the motion trajectory in the area outside the touch panel, the communication unit is configured to establish a communication connection with the terminal, and send the second signature data to the terminal to Make the terminal extract data corresponding to the first signature feature point and the second signature feature point from the first signature data and the second signature data, and extract the data corresponding to the first signature feature point and the second signature feature point Matching and comparing with the data of each feature point in the signature template data to determine whether the signature authentication is passed, the first signature data includes the coordinate information of the contact point between the stylus and the touch panel and the handwriting at the contact point. Pen pressure information on the touch panel. 18. The stylus pen according to claim 17, wherein the sensor unit is further configured to detect the acceleration of the stylus pen, the The pressure area information and the shape information of the pressure area that the pen is subjected to pressure by the user, and the distance information between the pressure area of the stylus pen and the pen end of the stylus pen. 19. The stylus according to claim 17 or 18, wherein the communication unit is further configured to receive control information on the sampling time and sampling frequency of the sensor unit sent by the terminal, so as to control the The sampling time and sampling frequency of the first signature data and the second signature data are kept synchronized. 20. A signature authentication system, comprising the terminal of claim 13 and the stylus of claim 17.

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