JP6660193B2 - Electronic signature management system - Google Patents

Description

  The present invention relates to an electronic signature management system that manages electronic signatures input by handwriting with a pen input device or the like.

  2. Description of the Related Art Conventionally, there has been provided an electronic signature system for performing personal authentication by using an electronic signature input by handwriting with a pen input device. In such an electronic signature authentication system, handwriting information at the time of handwriting input of a personal signature is recorded, and personal authentication is performed based on whether or not the handwriting information matches.

  Further, as disclosed in Patent Document 3 below, in recent years, personal authentication has been performed based on not only two-dimensional information of handwriting but also three-dimensional position information of handwriting.

JP 2007-226703 A JP 2012-48281 A Japanese Patent Application Laid-Open No. 2012-220972

  However, in the conventional electronic signature system, in the case of a system that generates a signed document by superimposing the input handwriting image of the input electronic signature on the signature field of the signature document, a third party who obtains the signed document image Can copy and copy the signature handwriting image on the image, so that a malicious third party can easily create a forged signed document impersonating the person.

  The present invention has been made in view of such a problem, and even when generating a signed document in which a handwriting image of an electronic signature is superimposed and displayed on a signature field of a signature document, creation of a forged signed document It is an object of the present invention to provide an electronic signature management system capable of preventing the problem.

  In order to solve the above-mentioned problem, an electronic signature management system according to the present invention is an electronic signature management system that manages an electronic signature handwritten by a pen input device or a touch input device, comprising a display and an original signature of the electronic signature. A degraded signature handwriting image generation unit that generates a degraded signature handwriting image obtained by irreversibly degrading a handwriting image, and associating information regarding the electronic signature with a pixel color that is a color of a pixel forming a screen of the display. A pixel color conversion table storing section for recording a pixel color conversion table for recording the original signature handwriting image and the degraded signature handwriting image, but not including the degraded signature handwriting image. And the pixel color conversion A pixel color code generation unit that generates a pixel color code that is a collection of the pixel colors by converting the pixel color code into a pixel color code by referring to the degraded signature handwriting image and the pixel color code. A signed document image generating unit that generates a signed document image superimposed on a predetermined position, and the pixel color code of the signed document image in order to simply prove the authenticity of the signed document image. And a simple certifying unit for decoding with reference to the pixel color conversion table and decoding with the first decoding key to restore the simple signature information.

  The electronic signature management program according to the present invention is an electronic signature management program for causing a computer to manage an electronic signature handwritten by a pen input device or a touch input device. A degraded signature handwriting image generating step of generating a degraded degraded signature handwriting image, and including the degraded signature handwriting image without including the original signature handwriting image; By encrypting, by referring to the pixel color conversion table that records information of the electronic signature and the correspondence between the pixel colors that are the colors of the pixels constituting the display screen, the pixel colors are converted to the pixel colors. A collection of said pixel colors A pixel color code generation step of generating a pixel color code, a signed document image generation step of generating a signed document image in which the deteriorated signature handwriting image and the pixel color code are superimposed on a predetermined position of the signature document, In order to simply prove the authenticity of the signed document image, the pixel color code of the signed document image is decrypted with reference to the pixel color conversion table and decrypted with a first decryption key. And a simple certification step for restoring the simple signature information.

Further, the electronic signature management method according to the present invention is an electronic signature management method for managing an electronic signature handwritten by a pen input device or a touch input device with a computer,
A degraded signature handwriting image generating step of generating a degraded signature handwriting image obtained by irreversibly degrading an original signature handwriting image of the electronic signature; and The simple sign information on the sign is encrypted by the first encryption key, and the pixel color conversion table for recording the correspondence between the information on the electronic sign and the pixel color that is the color of the pixel constituting the display screen is referred to. Converting the pixel color code into a pixel color code, thereby generating a pixel color code which is an aggregate of the pixel colors, and converting the deteriorated signature handwriting image and the pixel color code into a predetermined position on a signature document. Generate a signed document image superimposed on the document In the signed document image generation step, and in order to simply prove the authenticity of the signed document image, the pixel color code of the signed document image, while decoding with reference to the pixel color conversion table, And a simple certification step of restoring the simple signature information by decoding with the first decoding key.

  According to the present invention, even when a signed document is generated by superimposing the input handwriting image of the electronic signature on the signature field of the signature document, it is possible to prevent unauthorized copying of the signature handwriting image and prevent forgery signature The creation of the document can be prevented, and the authenticity of the signed document can be proved.

FIG. 1 is a schematic diagram schematically showing a configuration of an electronic signature management system according to an embodiment of the present invention. FIG. 2 is a schematic diagram schematically showing the configuration of the electronic signature management terminal according to the embodiment of the present invention. FIG. 3 is a block diagram schematically showing functions of the electronic signature management system according to the embodiment of the present invention. FIG. 4 is a schematic diagram schematically showing a configuration of the electronic signature management server according to the embodiment of the present invention. FIG. 5 is a diagram illustrating an image in a signature column of a signed document image according to the embodiment of the present invention. FIG. 6 is a flowchart showing the flow of the electronic signature registration process in the electronic signature management system according to the embodiment of the present invention. FIG. 7 is a flowchart showing the flow of the electronic signature certification process in the electronic signature management system according to the embodiment of the present invention.

  Hereinafter, an electronic signature management system according to an embodiment of the present invention will be described in detail with reference to the drawings. In the present embodiment, a case will be described as an example in which an electronic signature management system manages an electronic signature in which a patient who undergoes an operation signs a surgical agreement on a PC terminal using a digital pen which is a pen input device.

  FIG. 1 is a schematic diagram schematically showing the configuration of the electronic signature management system according to the present embodiment. FIG. 2 is a schematic diagram schematically illustrating a configuration of the electronic signature management terminal according to the present embodiment. FIG. 3 is a block diagram schematically illustrating functions of the electronic signature management system according to the present embodiment. FIG. 4 is a schematic diagram schematically showing the configuration of the electronic signature management server according to the present embodiment. FIG. 5 is a diagram illustrating an image of a signature column of a signed document image according to the present embodiment.

  As shown in FIG. 1, the electronic signature management system 1 includes an electronic signature management terminal 10 used by a signed patient and a management server 50. The electronic signature management terminal 10 and the management server 50 are communicably connected via a network 5 such as a LAN or the Internet.

  As shown in FIG. 2, the electronic signature management terminal 10 includes a PC main body 11, a display 40 for displaying output information from the PC main body 11, and an input device 42 for inputting information to the PC main body 11. I have.

  The PC main body 11 includes an arithmetic unit 12 such as a CPU (Central Processing Unit) for performing various arithmetic operations, a HDD (Hard Disc Drive) for storing various information, and a RAM (Random) used as a work area for arithmetic processing. Access Memory).

  The storage device 13 stores a program storage unit 131 for storing programs such as an OS (operating system), an electronic signature registration program, and an electronic signature simple certification program installed in the PC main body 11, and a signed document image. A signed document image storage section 132 to be stored, a pixel color conversion table storage section 133, a key storage section 134, and a video memory 135 for temporarily storing screen contents displayed on the display 40 are provided.

  The pixel color conversion table stored in the pixel color conversion table storage 133 stores correspondence between predetermined information and the color (pixel color) of each pixel (dot) constituting the screen of the display 40 (video memory 135). Is a table in which is recorded. The colors of the pixels that compose the screen are determined by the RGB values of 256 gradations, and 16,777,216 colors can be obtained. Therefore, by using a pixel color conversion table, one pixel is theoretically 16,777,216 types of information can be recorded.

  In the present embodiment, the pixel color code is a set of colors (pixel colors) of pixels that are obtained by converting colors based on a pixel color conversion table. It is a collection of 2,500 pixel colors in a square shape with 50 pixels vertically and 50 pixels horizontally. Of course, the size, shape, number of dots, and the like of the pixel color code can be changed as appropriate, and a circular or triangular pixel color code may be used.

  The key storage unit 134 records an encryption key for encryption and a decryption key for decryption. Specifically, an encryption key A, which is a first encryption key used when encrypting simple signature information described later, a decryption key A, which is a first decryption key used when decrypting simple signature information, An encryption key B, which is a second encryption key used when encrypting the detailed signature information described later, is recorded in the key storage unit 134.

  The input device 42 includes a keyboard 43, a mouse 44, and a pen tablet 46 as a pen input device. The pen tablet 46 is composed of a flat tablet main body 47 and a digital pen 48. When a signing patient grasps the digital pen 48 and moves it on the tablet main body 47, the tertiary tertiary axis of the tip of the digital pen 48 on the time axis is obtained. Original (XYZ coordinate) locus information is input to the PC main body 11 and recorded in the storage device 13.

  Note that among the locus information of the digital pen 48, the height (Z-axis) information of the tip of the digital pen 48 from the tablet body 47 is stored in the case where the tip of the digital pen 48 is far from the tablet body 47. When the tip of the digital pen 48 is in contact with the tablet body 47, the height is the contact pressure (pen pressure).

  That is, by writing a signature in the same manner as a patient signs a piece of paper using the pen tablet 46, the trajectory information of the digital pen 48 including time information is input from the pen tablet 46 to the PC main body 11, and the time axis It is possible to generate a handwriting image (black and white) of the patient's signature from the above-mentioned signature trajectory information, and also to generate signature handwriting information on the time axis.

  Focusing on the functions, as shown in FIG. 3, the PC main body 11 of the electronic signature management terminal 10 includes a deterioration signature handwriting image generation unit 21, a pixel color code generation unit 22, a signed document image generation unit 23, , A detailed signature information generation unit 24, and a simple certification unit 31. The functions of these units are realized by the arithmetic unit 12 executing various programs stored in the program storage unit 131.

  The deteriorated signature handwriting image generation unit 21 generates a deteriorated signature handwriting image in which the image quality of the handwriting image of the patient's signature input from the pen tablet 46 is irreversibly deteriorated. The deteriorated signature handwriting image is displayed in a signature field of a signed document image described later.

  The deteriorated signature handwriting image is a small-sized image in which the image quality of the original signature handwriting image generated based on the locus information of the digital pen 48 received from the tablet main body 47 is reduced. For example, in an original signature handwriting image, every 16 pixels of 4 × 4 pixels (dots) are replaced with a dominant white or black color in the area, thereby deteriorating signature handwriting. An image is generated.

  FIG. 5 is a view for explaining the display of the signature field of the signed document image according to the present embodiment. FIG. 5A is a diagram showing a deteriorated signature handwriting image to which a pixel color code displayed in a signature column is added, and FIG. 5B is a diagram showing the pixel color code in an enlarged manner. FIG. 5C is a diagram showing an original signature handwriting image.

  As shown in FIG. 5, the deteriorated signature handwriting image can be seen at a glance that it is not an original handwriting, as compared with the original signature handwriting image, but the image quality is maintained such that the signer can determine whether it is his / her own signature. are doing.

  Of course, the degradation method used when generating the degradation signature handwriting image can be changed as appropriate. If it is an irreversible degradation method, a method of reducing the image, thinning out the dots, and then enlarging the original size, or a plurality of methods can be used. May be combined. In addition, the image quality of the degraded signature handwriting image can be changed as appropriate, so that it is deteriorated at a glance that it is not the original signature handwriting, and at the same time that the signer knows that it is a degraded image of his / her signature. Any quality is acceptable.

  In the present embodiment, the deteriorated sign handwriting image generation unit 21 generates the deteriorated sign handwriting image in real time even during the signing of the patient, and displays the deteriorated sign handwriting image in the middle of the sign at any time in the signature field of the signature document. I do. Of course, the display of the deteriorated sign handwriting image in the middle of the sign may not be performed.

  The pixel color code generation unit 22 generates a pixel color code to be displayed beside the degraded signature handwriting image in the signed document image based on the information of the electronic signature input from the pen tablet 46 by the patient.

  The pixel color code stores the name of a signed document signed by the patient (surgery agreement), the date of signing, a handwritten signature image, and detailed signature information to be described later, as simple signature information on the input electronic signature. Contains location information.

  First, the pixel color code generation unit 22 stores the signature document name, the degraded signature handwriting image, the signature date, and the detailed signature information storage location information, which are the simple signature information, in the encryption key stored in the key storage unit 134. A, the encrypted simple sign information is converted into a pixel color for each pixel with reference to the pixel color conversion table recorded in the pixel color conversion table storage unit 133, and a set of pixel colors is obtained. Generates a 50 x 50 pixel pixel color code.

  The signed document image generation unit 23 uses the degraded signature handwriting image generated by the degraded signature handwriting image generation unit 21 and the pixel color code generated by the pixel color code generation unit 22 to generate a simple certification information including simple signature information. Generate a signed document image. The signed document image is a file in a general lossless compressed image file format such as a bitmap (BMP) or PNG, and can be opened and displayed by a general image browsing application or a browser.

  The signed document image file is converted to the lossless compressed image file format because if the image file format is the irreversibly compressed image format, the image quality deteriorates, and the pixel color code cannot be decoded in the certification process described later. is there.

  Specifically, the signed document image generating unit 23 superimposes the deterioration sign handwriting image and the pixel color code on the signature field of the operation agreement, which is a document displayed on the display 40, when performing the electronic signature. Generate the displayed signed document image. The deteriorated signature handwriting image is superimposed and displayed on the signature section of the image of the surgical consent form, and the pixel color code is superimposed and displayed near the lower right of the deteriorated signature handwriting image (see FIG. 5). The file of the generated signed document image is recorded in the signed document image storage unit 132.

  The detailed signature information generation unit 24 generates detailed signature information including an original signature handwriting image for detailed certification, and records the generated detailed signature information in the detailed signature information storage unit 532 of the management server 50. Specifically, the detailed signature information generation unit 24 generates signature handwriting information from the original signature handwriting image of the electronic signature and the above-described signature locus information on the time axis as the detailed signature information.

  The detailed signature information generation unit 24 encrypts the original signature handwriting image, which is the generated detailed signature information, and the signature handwriting information on the time axis with the encryption key B stored in the key storage unit 134. It is recorded as detailed signature information in the detailed signature information storage unit 532. The handwriting movement information including the time information can be reproduced as a moving image on the real time axis by the detailed certification unit 58 described later.

  The simple certification unit 31 decrypts the simple sign information described above and displays the decrypted simple sign information on the display 40 in order to simply prove the authenticity of the signed document image. Specifically, first, the simple certification unit 31 acquires the pixel color code in the signed document image displayed on the display 40 from the video memory 135.

  Thereafter, the simple certifying unit 31 decodes the pixel color code by using the decoding key A recorded in the key storage unit 134, and also simply certifies the authenticity of the signed document image in the decoded information. Is displayed on the display 40.

  As shown in FIG. 4, the management server 50 includes an arithmetic device 52 such as a CPU (Central Processing Unit) for performing various arithmetic operations, an HDD (Hard Disc Drive) for storing various information, and a work area for arithmetic processing. And a storage device 53 such as a RAM (Random Access Memory) used as a storage device.

  The storage device 53 stores a program storage unit 531 for storing various programs such as an OS (operating system) and an electronic signature detailed certification program installed in the management server 50, and records detailed signature information of the electronic signature. It has a detailed signature information storage unit 532 and a key storage unit 534 in which the decryption key B is recorded.

  Further, as shown in FIG. 3, focusing on the functions, the management server 50 includes a detailed certifying section 58 for certifying the authenticity of the signed document image with administrator authority in detail. The detailed certification unit 58 uses the decryption key B stored in the key storage unit 534 to decrypt the detailed signature information in order to explain the authenticity of the signed document image in detail.

  When acquiring the detailed signature information, the detailed certification unit 58 stores the detailed signature information in the management server 50 based on the storage location information of the detailed signature information included in the simplified signature information decrypted from the pixel color code by the simplified certification unit 31. Access the section 532.

  The decrypted detailed signature information is displayed on a display directly connected to the management server 50, or transmitted to the electronic signature management terminal 10 via the network 5 and displayed on the display 40. The detailed signature information includes the original signature handwriting image and the signature handwriting information, and the detailed certification unit 58 displays the original signature handwriting image and the signature handwriting video which is the movement of the tip of the digital pen 48 at the time of the signature. Can be.

  The configuration of the electronic signature management system 1 has been described above. Next, the flow of electronic signature registration processing in the electronic signature management system 1 will be described. FIG. 6 is a flowchart illustrating a flow of the electronic signature registration process in the electronic signature management system according to the present embodiment.

  First, in S10, the electronic signature management terminal 10 displays the operation agreement on the display 40 in order to show the contents of the operation agreement to the patient who performs the electronic signature. If the patient agrees with the contents of the surgical agreement, the patient moves the cursor on the display 40 to the signature field of the surgical agreement, starts the electronic signature by holding the digital pen 48 and moving it on the tablet body 47 ( S11).

  When the digital pen 48 is moved on the tablet main body 47, information on the movement of the tip of the digital pen 48 (three-dimensional trajectory information on the time axis) is transmitted from the pen tablet 46 to the PC main body 11 and stored in the storage device 13. It is temporarily recorded as on-axis sine locus information (S12).

  In S12, when the sign trajectory information starts to be recorded, the deteriorated sign handwriting image generation unit 21 generates a deteriorated sign handwriting image in the middle of the present time from the sign handwriting information up to the present time at a predetermined cycle (for example, every 1 s). Then, it is superimposed and displayed on the signature field of the operation agreement written on the display 40 (S13). Thereby, the patient can perform the electronic signature while watching the signature in the middle of writing.

  When the patient who has finished writing the electronic signature inputs the end of the electronic signature via the input device 42 (S14), the process proceeds to S15, where the pixel color code generation unit 22 generates a pixel color code. As described above, the pixel color code includes the signature document name (surgery agreement), the signature date, the deteriorated signature handwriting image, and the detailed signature information storage location information as simple signature information. The pixel color code generation unit 22 generates the pixel color code after encrypting the simple sign information with the encryption key A.

  In S16, the signed document image generation unit 23 generates a signed document image in which the completed degraded signature handwriting image and the pixel color code are superimposed and displayed at a predetermined position on the image of the surgical agreement, and the display 40 In addition to the above, the generated signed document image is recorded in the signed document image storage unit 132.

  Subsequently, in S18, the detailed signature information generation unit 24 generates detailed signature information and records it in the detailed signature information storage unit 532 of the management server 50. As described above, the detailed signature information includes the original signature handwriting image of the electronic signature and the signature handwriting information, and the detailed signature information is encrypted with the encryption key B. This completes the electronic signature registration process.

  Next, a description will be given of a flow of a process of proving that the signed document image is genuinely electronically signed by the patient based on the registered electronic signature information using the electronic signature management system 1. FIG. 7 is a flowchart illustrating a flow of a certification process in the electronic signature management system according to the present embodiment.

  In the present embodiment, the simplified simple certification using the simple sign information recorded in the pixel color code included in the signed document image recorded in the signed document image storage unit 132 and the detailed sign information storage unit 532 Detailed detailed proof is performed using the recorded detailed signature information.

  The scene in which the authenticity of the signed document image is required is as follows. When a patient who has registered a surgical consent form with an electronic signature in the electronic signature management system 1 has made an objection to the contents of the operation, hospital staff has A case may be considered in which the signed operation consent form (signed document image) is displayed on the display 40 for the patient to explain that the patient has agreed to the operation contents before the operation.

  First, in step S20, a hospital staff member operates the electronic signature management terminal 10 to search the signed document image storage unit 132 and selects a signed document image electronically signed by the patient while sitting with the patient. Is displayed on the display 40. Here, the signed document image is displayed by the browser installed in the PC main body 11 and recorded in the program storage unit 131.

  Then, although it is a deteriorated signature handwriting image having a low resolution, a surgical consent form in which the signature handwriting image signed by the patient is drawn in the signature section is displayed on the display 40, so that the hospital staff can give the patient a Can explain that the patient agreed to the operation content before the operation.

  If the patient is satisfied with the contents of the operation, the process ends here. On the other hand, if the patient argues that this signed surgical consent was a fake copy of my signature, and claims that I have not signed this surgical consent, , S21, and starts the simple certification process.

  The simple certification process is performed by activating a simple certification program (simple certification unit 31) installed in the PC main body 11 (S22). When the simple certification program is instructed to decrypt the pixel color code while the simple certification program is running, the simple certification unit 31 decrypts the pixel color code in S25.

  In decryption in S25, first, the simple certification unit 31 searches and recognizes the pixel color code displayed on the display 40 with reference to the video memory 135. In S20, since the pixel color code is displayed in the signed document image displayed by the browser, the pixel color code is recognized by the simple certification unit 31.

  In this embodiment, since the signed document image is displayed on the display 40 at the same resolution, the simple certification unit 31 can acquire the pixel color code information from the video memory 135. When the document image is displayed on the display 40 after being enlarged or reduced, the simple certification unit 31 needs to directly acquire the pixel color code information from the signed document image storage unit 132.

  The simple certification unit 31 refers to the pixel color conversion table stored in the pixel color conversion table storage unit 133 to decrypt the pixel color code and decrypt the encrypted simple sign information.

  Specifically, each pixel included in the pixel color code is converted into information associated with the color, and the simple signature information in an encrypted state is restored. Subsequently, the simple certification unit 31 uses the decryption key A recorded in the key storage unit 134 to decrypt the encrypted simple signature information, and restores the simple signature information.

  By decoding the pixel color code in this manner, the simple certification unit 31 can restore the signature document name, the signature date, the deteriorated signature handwriting image, and the detailed signature information storage location information, which are the simple signature information. it can.

  In S26, the simple certification unit 31 displays, on the display 40, information (signature document name, sign date, degraded sign handwriting image) necessary for the simple certification among the decrypted simple signature information.

  If the simple signature information displayed on the display 40 completely matches the content of the signed document image displayed on the display 40, the signed document image is copied from an illegally obtained signature handwriting image. It is possible to simply prove that the document image is not a falsified signed image such as a falsified one.

  If the patient is convinced by the simple proof that he has agreed to the operation in advance, the explanation to the patient is finished. On the other hand, if the patient is not yet satisfied with the simple certification, the process proceeds to S30 to start the detailed certification.

  In the present embodiment, the detailed certification is configured so that only a system administrator having the administrator authority of the electronic signature management system 1 can perform the detailed certification. Therefore, if the hospital staff is not a person having administrator authority, it is necessary to call a system administrator to perform the detailed certification.

  In the present embodiment, the detailed certification program for performing the detailed certification is installed only in the management server 50, and the system administrator who is present with the patient and the staff of the hospital sends the administrator authority from the electronic signature management terminal 10 to the management server 50. And perform detailed certification while operating the management server 50 remotely.

  Of course, the operation rule of the detailed proof can be changed as appropriate. When performing the detailed proof rather than the remote operation, the system administrator and the patient go to the place where the management server 50 is located and operate the management server 50 directly. Alternatively, the detailed certification program may be installed in the electronic signature management terminal 10 and the detailed certification may be performed in the electronic signature management terminal 10, but only the system administrator may execute the detailed certification program. You may comprise so that it can be used.

  In S31, first, the system administrator accesses the management server 50 from the electronic signature management terminal 10 and activates the detailed certification program (the detailed certification unit 58). Subsequently, in S32, the detailed certification unit 58 decrypts the encrypted detailed sign information recorded in the detailed signature information storage unit 532 using the decryption key B recorded in the key storage unit 534.

  In S33, the detailed signature information decrypted by the detailed certification unit 58 is transmitted to the electronic signature management terminal 10 and displayed on the display 40. The detailed signature information includes the original signature handwriting image whose image quality has not deteriorated and the signature handwriting information, and these detailed signature information that can only be decrypted by the system administrator ensures the authenticity of the signed document image. can do.

  In particular, the signature handwriting information is the signature locus information on the time axis, and it is possible to play back a movie while stepping forward or temporarily stopping playback, and by seeing this, the patient is supposed to be a document signed by himself. I have to convince.

  As described above, the electronic signature management system 1 according to the present embodiment has been described. However, according to the present embodiment, a degraded signature handwriting image with degraded image quality is displayed on a signed document image that is freely accessible. Even if the signed document image is illegally acquired by a third party, only the degraded signature handwriting image can be copied, thereby preventing a malicious third party from falsifying or falsifying the signed document.

  In addition, since the deteriorated signature handwriting image displayed on the signed document image is an irreversibly deteriorated image of the original signature handwriting image, it is assumed that the data of the deteriorated signature handwriting image is acquired by a malicious third party. Nor can it restore the original signature handwriting image.

  In addition, the signed document image is a file in a general image file format, and does not require dedicated browsing software. A general image display software can display the signed document image.

  In addition, beside the degraded signature handwriting image of the signed document image, simple signature information for simply proving the authenticity of the signed document image is encrypted by the encryption key A beside the signed document image. In an environment having a decryption key A for decrypting the color code, the simple signature information is decrypted and displayed, so that the authenticity of the signed document image can be simplified. Can be proved.

  Further, the simple signature information is recorded as a pixel color code after being encrypted. Even if the deteriorated signature handwriting image and the pixel color code are copied to a third party, the simple signature information must have the decryption key A. For example, the simple signature information cannot be decrypted, and information other than the deteriorated signature handwriting image is not illegally acquired.

  In addition, since the pixel color code is pasted next to the degraded signature handwriting image, even if the plagiarized degraded signature handwriting image is pasted on another signature document and the signed document image is forged, the pixel color code is forged. As long as it is not possible, by decoding the simple signature information from the pixel color code, it can be easily revealed that the signed document image is not authentic.

  Even if the simple signature information is illegally decrypted from the pixel color code and plagiarized, the simple signature information does not include the original signature handwriting image or signature handwriting information. Important original signature handwriting images and signature handwriting information are not plagiarized.

  Also, the original signature handwriting image and the signature handwriting information, which are the detailed signature information, are not recorded in the electronic signature management terminal 10 at all, and are encrypted by the encryption key B different from the encryption key A as the detailed signature information. In addition, it is very difficult to steal original signature handwriting images and signature handwriting information because they are recorded in the management server 50 accessible only by the system administrator.

  The embodiments of the present invention have been described above. However, the embodiments of the present invention are not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention. . For example, the function of the electronic signature management terminal may be realized by cloud computing via a network.

  Further, in the above embodiment, the storage / decoding of the detailed signature information is performed by the management server connected to the electronic signature management terminal via the network. However, the storage / decoding of the detailed signature information can be performed within the electronic signature management terminal. May be configured.

  Further, in the above embodiment, only the handwriting image of the signature is included in the deteriorated signature handwriting image, but when the signature document is electronically signed, the date of signing is input with a digital pen, and this date handwriting image is displayed. The deterioration signature handwriting image may be included.

  Also, the contents of the simple signature information and the detailed signature information can be changed as appropriate. Also, the information included in the pixel color code of the simple signature information can be changed as appropriate, and it is not necessary to include all of the simple signature information in the pixel color code. Alternatively, information indicating the characteristics of the image may be included in the pixel color code.

  In addition, since the encryption key can be decrypted with time, it is desirable to periodically change the encryption keys A and B and the decryption keys A and B. Further, the pixel color conversion table may record the association with the color not for each pixel but for each of a plurality of pixel groups.

  In the above-described embodiment, the pen input device including the tablet body and the digital pen is used as the input device for inputting the electronic signature by handwriting. However, other input devices may be used as long as the input device can input the electronic signature by handwriting. be able to. For example, a touch input device such as a touch screen or a touch pad that can input a trajectory by touching with a finger may be employed.

REFERENCE SIGNS LIST 1 electronic signature management system 10 electronic signature management terminal 11 PC main body 12 arithmetic unit 13 storage device 131 program storage unit 132 signed document image storage unit 133 pixel color conversion table storage unit 134 key storage unit (encryption keys A, B, decryption key A)
135 Video memory 21 Degraded signature handwriting image generation unit 22 Pixel color code generation unit 23 Signed document image generation unit 24 Detailed signature information generation unit 31 Simple certification unit 40 Display 42 Input device 43 Keyboard 44 Mouse 46 Pen tablet 47 Tablet body 48 Digital Pen 50 management server 52 arithmetic unit 53 storage device 531 program storage unit 532 detailed signature information storage unit 534 key storage unit 58 detailed certification unit 5 network

Claims (5)

In an electronic signature management system that manages electronic signatures input by handwriting with a pen input device or a touch input device,
Display and
A degraded signature handwriting image generation unit that generates a degraded signature handwriting image obtained by irreversibly degrading the original signature handwriting image of the electronic signature,
A pixel color conversion table storage unit that records a pixel color conversion table that records information on the electronic signature and a correspondence between a pixel color that is a color of a pixel configuring the screen of the display,
The simple signature information relating to the electronic signature, including the degraded signature handwriting image without including the original signature handwriting image, is encrypted with a first encryption key and converted to the pixel color with reference to the pixel color conversion table. By doing so, a pixel color code generation unit that generates a pixel color code that is an aggregate of the pixel colors,
A signed document image generation unit that generates a signed document image in which the deteriorated signature handwriting image and the pixel color code are superimposed on a predetermined position of the signature document,
In order to simply prove the authenticity of the signed document image, the pixel color code in the signed document image is decrypted with reference to the pixel color conversion table and decrypted with the first decryption key. A simple certification unit for restoring the simple signature information,
An electronic signature management system comprising: The original signature handwriting image, including signature handwriting information including the electronic signature time information, detailed signature information related to the electronic signature, a detailed signature information generation unit that encrypts with a second encryption key,
In order to prove the authenticity of the signed document image in detail, by decrypting the encrypted detailed signature information with a second decryption key, a detailed certification unit that restores the detailed signature information,
The electronic signature management system according to claim 1, further comprising:   The electronic signature management system according to claim 2, wherein the simple signature information includes information on a storage location of the detailed signature information. In an electronic signature management program for causing a computer to manage an electronic signature input by handwriting with a pen input device or a touch input device,
A degraded signature handwriting image generating step of generating a degraded signature handwriting image obtained by irreversibly degrading the original signature handwriting image of the electronic signature,
The simple signature information related to the electronic signature, including the deteriorated signature handwriting image without including the original signature handwriting image, is encrypted with a first encryption key, and the information related to the electronic signature and pixels constituting a display screen are displayed. A pixel color code generating step of generating a pixel color code which is an aggregate of the pixel colors by converting the pixel colors by referring to a pixel color conversion table that records correspondence between the pixel colors and the pixel colors. ,
A signed document image generating step of generating a signed document image in which the deteriorated signature handwriting image and the pixel color code are superimposed on a predetermined position of the signed document,
In order to simply prove the authenticity of the signed document image, the pixel color code of the signed document image is decrypted with reference to the pixel color conversion table and decrypted with a first decryption key. A simple certification step of restoring the simple signature information;
An electronic signature management program for causing the computer to execute the following. An electronic signature management method for managing an electronic signature handwritten by a pen input device or a touch input device by a computer,
A degraded signature handwriting image generating step of generating a degraded signature handwriting image obtained by irreversibly degrading the original signature handwriting image of the electronic signature,
The simple signature information related to the electronic signature, including the deteriorated signature handwriting image without including the original signature handwriting image, is encrypted with a first encryption key, and the information related to the electronic signature and pixels constituting a display screen are displayed. A pixel color code generating step of generating a pixel color code which is an aggregate of the pixel colors by converting the pixel colors by referring to a pixel color conversion table that records correspondence between the pixel colors and the pixel colors. ,
A signed document image generating step of generating a signed document image in which the deteriorated signature handwriting image and the pixel color code are superimposed on a predetermined position of the signed document,
In order to simply prove the authenticity of the signed document image, the pixel color code of the signed document image is decrypted with reference to the pixel color conversion table and decrypted with a first decryption key. A simple certification step of restoring the simple signature information;
An electronic signature management method, comprising: