Document verification system and document verification method

Abstract

To perform signature verification of an electronic document, without allowing a user to upload a whole electronic document to a server side.SOLUTION: A document verification system performs signature verification of an electronic document, wherein a server includes an allocation part for allocating a predetermined module to a terminal, the terminal includes an extraction part for operating the allocated module, and extracting certificate data on the basis of the electronic document, the server includes a certificate verification part for verifying the extracted certificate data, and the terminal includes an alternation verification part for operating the allocated module, and verifying alternation of the electronic document.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a document verification system and a document verification method. [Background technology]

[0002] In recent years, while electronic documents have become increasingly paperless, the creator of electronic documents has become unclear and it has become more difficult to determine whether or not they have been tampered with. As a result, users are increasingly required to verify the signatures of the electronic documents they receive to determine who created them and whether they have been tampered with.

[0003] For this reason, users have had to use an application installed on their own devices to verify the signatures of electronic documents they received. However, since the provision of a service for verifying signatures on electronic documents using a web browser, it has become unnecessary to install an application for signature verification on user devices (Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] SkyCom Inc., "SkyPDF Verification Service website launched, enabling users to verify the validity of digital signatures and time stamps, check history information stamped with PDF seals, and detect tampering online", [online], March 1, 2022, PR TIMES Corporation, [Retrieved June 29, 2023], Internet<URL:https: / / prtimes.jp / main / html / rd / p / 000000009.000075093.html> Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, in the system providing the service of Non-Patent Document 1, signature verification processing is performed on the server side, and when a user attempts to verify the signature of an electronic document, the entire electronic document, including highly confidential plaintext, must be uploaded to the server. As a result, many users are reluctant to upload electronic documents. For this reason, the server side must perform electronic document management, such as by securely deleting the uploaded electronic document after the verification processing.

[0006] Furthermore, in the system of Non-Patent Document 1, devices and resources must be prepared on the server side for a web application for displaying electronic documents in a web browser and a web API for controlling the electronic documents. In particular, for devices and resources that implement the web API, it is necessary to take into consideration the number of simultaneous accesses to the web API, etc.

[0007] The inventors therefore realized that in a signature verification service for electronic documents, functions that previously ran on the server side can be downloaded to the client side and the downloaded functions can be operated on the client's web browser, allowing users to verify the signature of an electronic document without uploading the entire electronic document to the server side.

[0008] In view of the above problems, the present invention has an object to provide a document verification system and a document verification method that enable a user to verify a signature of an electronic document without uploading the entire electronic document to a server side. [Means for solving the problem]

[0009] The present invention provides the following solutions.

[0010] According to the first aspect of the invention, A document verification system for verifying a signature of an electronic document, comprising: The server includes an allocation unit that allocates a predetermined module to a terminal, the terminal includes an extracting unit that operates the assigned module to extract certificate data based on the electronic document; the server includes a certificate verification unit that verifies the extracted certificate data; the terminal includes a tampering verification unit that operates the assigned module to verify tampering of the electronic document; The present invention provides a document verification system module allocation unit.

[0011] According to the first aspect of the invention, the data required for certificate verification can be extracted based on the electronic document and the electronic document can be verified for falsification on the client side. This allows a user to verify the signature of an electronic document by simply uploading only the data required for verifying the certificate contained in the electronic document.

[0012] Furthermore, according to the invention relating to the first feature, since there is no need to extract data required for certificate validation based on an electronic document or to verify whether the electronic document has been tampered with on the server side, it is possible to omit devices and resources used for Web APIs, etc. that realize these functions.

[0013] In addition, according to the invention relating to the first feature, there is no need to upload the entire electronic document, including highly confidential plaintext, to the verification service server. Therefore, the server side does not require electronic document management to avoid security risks such as leakage of electronic documents by securely deleting the uploaded electronic document. Therefore, even users who are reluctant to upload the entire electronic document from the perspective of security risks can safely verify the signature of the electronic document.

[0014] The invention according to the second aspect is the invention according to the first aspect, The assigned modules provide a document verification system that runs in a web browser.

[0015] According to the second feature of the invention, it becomes possible to verify the signature of an electronic document using an assembler in a web browser of a terminal, thereby saving the user the trouble of having to install a dedicated application on the terminal.

[0016] The third aspect of the invention is the first aspect of the invention, A module operating on the server provides a document validation system that is composed of web components and / or web APIs.

[0017] According to the invention relating to the third feature, if a module running on a server is configured with Web components instead of WEB APIs, custom elements running on a Web browser become reusable, so that the processing performed by the module running on the server can be performed on a terminal, thereby reducing the burden on the server and, further, there is no need to prepare devices or resources on the server side for a Web app for displaying electronic documents in a Web browser and a WEB API for controlling the electronic documents.

[0018] The invention according to the fourth aspect is the invention according to the first aspect, the certificate data includes a public key certificate; The certificate verification unit provides a document verification system that verifies the public key certificate based on a trusted certificate.

[0019] According to the fourth feature of the invention, it is possible to verify, based on a trusted certificate, that the public key certificate contained in an electronic document has been issued by a trusted public key certificate authority or certification authority (CA).

[0020] The fifth aspect of the invention is the first aspect of the invention, the certificate data includes information regarding a public key certificate and a revocation list; The certificate validation unit provides a document validation system that verifies the public key certificate based on information related to the revocation list.

[0021] According to the fifth feature of the invention, it becomes possible to verify whether a public key certificate has been revoked from the issuing public key certificate certification authority or certification authority (CA) based on a revocation list published by the certification authority.

[0022] The sixth aspect of the invention is the fourth or fifth aspect of the invention, The extraction unit further extracts information regarding a verification time, The certificate verification unit provides a document verification system that verifies the public key certificate based on information relating to the verification time.

[0023] According to the sixth feature of the invention, it is possible to extract the verification time used when verifying a public key certificate based on information regarding a trusted certificate or a revocation list, and it is further possible to verify whether the timing of verifying the public key certificate is within the validity period set in the public key certificate.

[0024] Although the present invention is in the category of terminal systems, similar actions and effects according to the category can be achieved in other categories such as document verification methods. Effect of the Invention

[0025] According to the present invention, it is possible to provide a document verification system and a document verification method that are capable of verifying a signature of an electronic document without uploading the entire electronic document to the server side. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a diagram for explaining an overview of a document verification system 1 according to an embodiment of the present invention. [Diagram 2] 1 is a configuration diagram of a document verification system 1 according to the present embodiment. [Diagram 3] 11 is a flowchart of a module allocation process executed by the document verification system 1 of the present embodiment. [Figure 4] 11 is a flowchart of a certificate verification process executed by the document verification system 1 of the present embodiment. [Diagram 5] 11 is a flowchart of a tampering verification process executed by the document verification system 1 of the present embodiment. [Figure 6] 1 is a diagram showing an example of the configuration of an electronic document to be subjected to signature verification in a document verification system 1 of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. Note that this is merely an example, and the technical scope of the present invention is not limited to this example.

[0028] [Overview of Document Verification System 1] An overview of a document verification system 1 according to one embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a diagram for explaining the overview of a document verification system 1 according to one embodiment of the present invention. The document verification system 1 is made up of a terminal 2 and a server 3, and is a system that performs signature verification of an electronic document.

[0029] The terminal 2 of the document verification system 1 is, for example, a terminal such as a desktop personal computer, a notebook computer, or a server, a mobile terminal such as a smartphone or a tablet terminal, or a wearable terminal such as a head-mounted display such as smart glasses or a smart watch.

[0030] Furthermore, the terminal 2 may be realized, for example, by one terminal device, or may be realized by a plurality of terminal devices.

[0031] The terminal 2 is connected to the above-mentioned terminal devices and other terminals and devices via a public line network or the like so as to be capable of data communications, and transmits and receives necessary data and information.

[0032] The server 3 of the document verification system 1 is, for example, a computer device such as a desktop personal computer, a notebook computer, or a server.

[0033] Furthermore, the server 3 may be realized, for example, by one terminal device, or may be realized by a plurality of terminal devices, or may be realized by a virtual device such as a cloud computer.

[0034] The server 3 is connected to the above-mentioned terminal devices and other terminals and devices via a public line network or the like so as to be able to communicate data, and transmits and receives necessary data and information.

[0035] Next, an overview of the processing executed by the document verification system 1 will be described. First, the server 3 assigns a predetermined module to the terminal 2 (step S1). Specifically, when a user who desires to verify the signature of the electronic document 100 displays the website of the document verification system 1 provided by the server 3 on a web browser by an output unit of the terminal 2, the server 3 downloads the module 400 to the terminal 2.

[0036] Next, terminal 2 operates the assigned module 400 to extract the certificate data 200 based on the electronic document 100 (step S2). Specifically, terminal 2 accepts input of the electronic document 100 for which signature verification is desired from the user in a web browser, extracts the signer's certificate data 200 from the signature data included in the accepted electronic document 100 or the associated signature data, and transmits the extracted certificate data 200 to the server. At this time, terminal 2 may extract and transmit verification information and / or verification time to server 3. There are no particular limitations on the method of input from the user, and the data may be input and acquired from another terminal device via a public line or the like.

[0037] The data structure of the electronic document 100 will be described with reference to FIG. 6. In the electronic document 100, signature data is embedded in plain text (hereinafter referred to as data to be signed). There are no particular limitations on the size of the signature data or the position at which it is embedded. Furthermore, the signature data only needs to be associated with the electronic document 100, and does not need to be embedded in the electronic document 100. The signature data includes a digest, certificate data 200, a portion of the verification time 230, a digest calculation algorithm, a signature algorithm, and information on the signer. The digest is hashed based on the data to be signed using a predetermined digest calculation algorithm, and is encrypted based on a private key using a signature algorithm. There are no particular limitations on these algorithms. The certificate data 200 includes a public key certificate 210.

[0038] Public key certificate 210 contains personal information such as the signer's name and affiliation, the signer's public key, and a signature from a public key certificate authority or Certification Authority (CA) (not shown), and is used to certify that the public key for decrypting the digest is correct.

[0039] The revocation list 220 is a list of revoked certificates published by a certification authority (CA) and is used to prove whether the public key certificate 210 has been revoked by the certification authority (CA) that issued it.

[0040] The verification time 230 is used when verifying the temporal validity of the public key certificate 210. In the example of Fig. 6, the verification time 230 includes a time stamp of the signing time. The time stamp of the signing time may be outside the signature data as long as it is within the electronic document 100. The time data used as the verification time 230 is optimally selected from the time stamp of the signing time or the current time obtained from the terminal 2 or the server 3, based on the signature data or the specification of the verifier (user).

[0041] The signing time stamp is obtained from a Time Stamping Authority (TSA).

[0042] Returning to Fig. 1, the server 3 verifies the extracted certificate data 200 (step S3). Specifically, the server 3 compares the trusted certificate 300 stored in advance in the server 3 with the certificate data 200 sent from the terminal 2, verifies whether the public key certificate 210 included in the certificate data 200 is correct, and sends the verification result to the terminal 2. Based on the received verification result, the terminal 2 determines whether the public key certificate 210 related to the electronic document 100 is correct. The trusted certificate 300 refers to a digital certificate issued by a certification authority (CA) (not shown).

[0043] Next, terminal 2 operates the assigned module 400 to verify whether or not the electronic document 100 has been tampered with (step S4). Specifically, terminal 2 verifies in a web browser whether or not the data to be signed in electronic document 100 has been tampered with by using the public key included in the signature data. If a signature time stamp is present outside the signature data, terminal 2 may verify that electronic document 100 existed before the time indicated by the signature time stamp and that the document has not been tampered with since that time.

[0044] The above is an overview of the process executed by the document verification system 1.

[0045] [System configuration of Document Verification System 1] The system configuration of a document verification system 1 of this embodiment will be described with reference to Fig. 2. The document verification system 1 is made up of a terminal 2 and a server 3, and is a terminal system for verifying a signature on an electronic document.

[0046] The document verification system 1 may include other terminals, devices, etc. For example, a different terminal 2 may be used for each user, in which case the document verification system 1 executes each process described below using the terminal 2, the server 3, and / or the other included terminals, devices, etc.

[0047] The terminal 2 may be realized, for example, by one terminal device, or may be realized by a plurality of terminal devices.

[0048] The terminal 2 may be, for example, a terminal such as a desktop personal computer, a notebook computer, or a server, a mobile terminal such as a smartphone or a tablet terminal, or a wearable terminal such as a head-mounted display such as smart glasses or a smart watch.

[0049] Terminal 2 is equipped with a control unit and a processing unit, such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). The control unit issues execution commands to the processing unit, communication unit, input unit, output unit, and memory unit, which will be described later, and the processing unit calculates data and determines the calculation results.

[0050] The terminal 2 includes a data storage unit such as a hard disk, a semiconductor memory, a recording medium, a memory card, etc. The data may be stored in a cloud service, a database, etc.

[0051] The terminal 2 includes a device as a communication unit for enabling communication with other terminals, devices, etc. The communication method may be wireless or wired.

[0052] The terminal 2 is assumed to have, as an input unit, functions necessary for operating the terminal 2. Examples of input methods include a liquid crystal display that realizes a touch panel function, a keyboard, a mouse, a pen tablet, hardware buttons on the device, and a microphone for voice recognition. The present invention is not particularly limited in function depending on the input method.

[0053] The terminal 2, as an output unit, is provided with functions necessary for a user of the document verification system 1 to operate the terminal 2. Examples of output methods include display on a liquid crystal display, a PC display, projection on a projector, and audio output. The present invention is not particularly limited in function by the output method.

[0054] The control unit cooperates with the processing unit to realize an extraction unit 20 and a tampering verification unit 21 .

[0055] The server 3 may be realized, for example, by one terminal device, by a plurality of terminal devices, or by a virtual device such as a cloud computer.

[0056] Like the terminal 2, the server 3 is a computer device such as a desktop computer, a notebook computer, or a server.

[0057] The server 3 is equipped with a control unit and a processing unit, such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). The control unit issues execution commands to the processing unit, communication unit, and memory unit described below, and the processing unit calculates data and determines the calculation results.

[0058] The server 3 includes a data storage unit such as a hard disk, a semiconductor memory, a recording medium, a memory card, etc. The data may be stored in a cloud service, a database, etc.

[0059] The server 3 includes a device as a communication unit for enabling communication with other terminals, devices, etc. The communication method may be wireless or wired.

[0060] The control unit cooperates with the processing unit to realize a certificate verification unit 30 and a module allocation unit 31. The storage unit stores a trusted certificate 300 issued by a certification authority (CA) (not shown) and a module 400 that the module allocation unit 31 downloads to the terminal 2.

[0061] The above is the system configuration of the document verification system 1.

[0062] [Module allocation process] The module allocation process executed by the document verification system 1 will be described with reference to Fig. 3. The module allocation process is the process performed in the above-mentioned S1. Fig. 3 is a diagram showing a flowchart of the module allocation process executed by the document verification system 1.

[0063] The server 3 assigns a predetermined module to the terminal 2 (steps S11 to S13). Specifically, first, the terminal 2 accesses the server 3 from a web browser (step S11). More specifically, a user who wishes to verify the signature of the electronic document 100 accesses the website of the document verification system 1 provided by the server 3 from the web browser implemented in the terminal 2 via a communication unit.

[0064] Next, the module allocation unit 31 of the server 3 allocates the module 400 to the terminal 2 (step S12). Specifically, the module allocation unit 31 of the server 3 downloads the module 400 stored in the storage unit to the terminal 2 via the communication unit.

[0065] Next, the terminal 2 receives the downloaded module 400 (step S13). Specifically, the terminal 2 receives the downloaded module 400 from the module allocation unit 31 of the server 3 via the communication unit, and stores it in the storage unit.

[0066] The above is the module allocation process.

[0067] [Certificate verification process] The certificate verification process executed by the document verification system 1 will be described with reference to Fig. 4. The certificate verification process is the process performed in the above-mentioned steps S2 to S3. Fig. 4 is a diagram showing a flowchart of the certificate verification process executed by the document verification system 1.

[0068] The extraction unit 20 of the terminal 2 operates the module 400 downloaded in step S13 described above to extract the certificate data 200 based on the electronic document 100 (steps S21 to S22). Specifically, first, the control unit of the terminal 2 operates the module 400 downloaded and stored in the storage unit in a Web browser displayed by the output unit, and the user inputs the electronic document 100 for which signature verification is desired from the Web browser installed in the terminal 2, whereby the input unit of the terminal 2 accepts the input of the electronic document 100, and the extraction unit 20 extracts the signer's certificate data 200 from the signature data included in the accepted electronic document 100 or the associated signature data (step S21). In step S21, verification information and / or verification time may also be extracted.

[0069] Next, the extracted certificate data 200 is transmitted to the server 3 by the communication unit of the terminal 2 (step S22). In step S22, the verification information and / or the verification time extracted in step S21 may be transmitted to the server 3. There is no particular limitation on the method of input from the user, and the data may be input and acquired from another terminal device via a public line or the like. In addition, there is no particular limitation on the method of extracting the certificate data 200 from the electronic document.

[0070] The data structure of the electronic document 100 is as described above.

[0071] Next, the server 3 verifies the transmitted certificate data 200 based on the trusted certificate 300 stored therein, and transmits the verification result to the terminal 2 as the certificate verification result (steps S31 to S34). Specifically, the communication unit of the server 3 receives the transmitted certificate data 200 (step S31). In step S31, if the verification information and / or the verification time 230 was transmitted in step S22, the communication unit also receives the verification information and / or the verification time 230.

[0072] Next, the certificate verification unit 30 of the server 3 compares the trusted certificate 300 stored in advance in the memory unit of the server 3 with the received certificate data 200, and verifies whether the public key certificate 210 included in the certificate data 200 is correct (step S32). The trusted certificate 300 is issued by a predetermined certification authority (CA), and the trusted certificate 300 may be stored in the memory unit of the server 3 at any time before the certificate data 200 is verified.

[0073] In step S32, specifically, the certificate verification unit 30 of the server 3 verifies the certificate chain of the public key certificate 210 based on the trusted certificate 300, verifies whether the certificate authority that issued the public key certificate 210 is trustworthy, and sets this verification result as a first verification result. The trusted certificate 300 is a certificate (root certificate) of a trusted certificate authority that is the root of the certificate chain. Note that the root certificate used as the trusted certificate 300 may be one included in the certificate data 200 or the verification information. If one or more intermediate certificate authorities are involved in the certificate chain, the server 3 verifies the certificate chain of the public key certificate 210 based on the root certificate and all intermediate certificates. The intermediate certificate used is one stored in the server 3, the certificate data 200, or the verification information.

[0074] Furthermore, in step S32, the certificate validation unit 30 of the server 3 verifies whether the public key certificate 210 has been revoked based on the revocation list 220 stored in the server 3, the certificate data 200, or the validation information. This validation result is set as the second validation result. If the revocation list 220 included in the certificate data 200 and the validation information is invalid, or if the revocation list 220 is not included in the certificate data 200 and the validation information, the certificate validation unit 30 obtains the latest revocation list from a server that publishes it.

[0075] Furthermore, in step S32, the certificate verification unit 30 of the server 3 may verify whether the public key certificate 210 is within the validity period based on the verification time 230 received in step S31. This verification result is called a third verification result.

[0076] Next, the communication unit of the server 3 transmits the result of the verification in the above-mentioned step S32 to the terminal 2 as the certificate verification result (step 33). Specifically, based on the above-mentioned first to third verification results, the result of whether the public key certificate 210 is correct or not is transmitted to the terminal 2 as the certificate verification result. Note that, as the certificate verification result, separate results of the first to third verification results may be transmitted to the terminal 2.

[0077] Next, the communication unit of terminal 2 receives the certificate verification result from the server 3 (step S34). At this time, the output unit of terminal 2 may output the received certificate verification result to terminal 2. As an output method, the result may be displayed on a web browser of terminal 2, or may be output by another method so that the user of document verification system 1 can recognize the result.

[0078] This completes the certificate verification process.

[0079] [Tamper Verification Process] The falsification verification processing executed by the document verification system 1 will be described with reference to Fig. 5. The falsification verification processing is the processing performed in S4 described above. Fig. 5 is a diagram showing a flowchart of the falsification verification processing executed by the document verification system 1.

[0080] First, the tampering verification unit 21 of the terminal 2 operates the module 400 downloaded in the above-mentioned step S13 to verify tampering of the electronic document 100 (steps S41 to S44). Specifically, the control unit of the terminal 2 operates the module 400 downloaded and stored in the storage unit in a Web browser displayed by the output unit, and the tampering verification unit 21 of the terminal 2 extracts a digest, a public key, and a one-way hash function algorithm from the signature data of the electronic document 100 by the Web browser of the terminal 2 (step S41).

[0081] Next, the falsification verification unit 21 of the terminal 2 generates a digest for verification (step S42). Specifically, the falsification verification unit 21 of the terminal 2 generates, as a digest for verification, a hash value of an arbitrary fixed length from the data to be signed of the electronic document 100 based on the algorithm extracted in step S41 by the web browser of the terminal 2. The algorithm of the one-way hash function is not particularly limited.

[0082] Next, the falsification verification unit 21 of the terminal 2 compares the extracted digest with the generated digest for verification using the extracted public key (step S43). Specifically, the digest is decrypted using the extracted public key, and it is determined whether the decrypted digest and the digest for verification match.

[0083] Next, the output unit of terminal 2 determines whether the decrypted digest matches the comparison digest and outputs the result as the signature verification result (step S44). As an output method, the result may be displayed on the Web browser of terminal 2, or may be output by other methods so that the user of document verification system 1 can recognize the result.

[0084] If the signature data includes a signature time stamp, in step S43, the tampering verification unit 21 of the terminal 2 may verify that the electronic document 100 existed before the time indicated by the signature time stamp and that the document has not been tampered with since that time. The tampering verification unit 21 may also verify the expiration date of signature verification of the electronic document 100 based on the signature time stamp. These verification results may be output as signature verification results in step S44.

[0085] This completes the tamper verification process.

[0086] According to document verification system 1, the data required for certificate verification from the electronic document and the verification of tampering of the electronic document can be performed on the client side, so that the user can verify the signature of the electronic document by simply uploading only the data required for verifying the certificate contained in the electronic document.

[0087] In addition, according to document verification system 1, since it is not necessary to extract data required for certificate verification from electronic documents and to verify the falsification of electronic documents on the server side, it is possible to omit devices and resources used for Web APIs and the like that realize these functions.

[0088] In addition, according to document verification system 1, there is no need to upload the entire electronic document, including highly confidential plaintext, to the verification service server. Therefore, the server side does not require electronic document management to avoid security risks such as leakage of electronic documents by securely deleting the uploaded electronic document. Therefore, even users who are reluctant to upload the entire electronic document from the perspective of security risks can safely verify the signature of the electronic document.

[0089] Furthermore, according to document verification system 1, if a module running on a server is configured with web components instead of web APIs, custom elements running on a web browser become reusable, so that the processing performed by the module running on the server can be performed on the terminal, thereby reducing the burden on the server.

[0090] Furthermore, the web browser used on terminal 2 of document verification system 1 is capable of executing assemblers that execute programs using WebAssembly (WASM). Therefore, signature verification of electronic documents can be performed simply by installing a web browser on the terminal, eliminating the need for users to install a dedicated application on their terminal.

[0091] In addition, according to the document verification system 1, it is possible to verify that the public key certificate contained in the electronic document has been issued by a trusted public key certificate authority or certification authority (CA) based on the trusted certificate.

[0092] In addition, according to the document verification system 1, it is possible to verify whether a public key certificate has been revoked by the issuing public key certificate certification authority or certification authority (CA) based on a revocation list published by the certification authority.

[0093] Furthermore, according to the document verification system 1, it is possible to verify whether the timing of verifying the public key certificate is within the validity period set in the public key certificate.

[0094] The above-mentioned means and functions are realized by a terminal (including a CPU, an information processing device, and various terminals) reading and executing a predetermined program. The program is provided, for example, in a form provided from one or more terminals via a network (cloud service, SaaS: Software as a Service). The program is also provided, for example, in a form recorded on a terminal-readable recording medium. In this case, the terminal reads the program from the recording medium, transfers it to an internal recording device or an external recording device, records it, and executes it. The program may also be recorded in advance on a recording device (recording medium) such as a magnetic disk, optical disk, or magneto-optical disk, and provided to the terminal from the recording device via a communication line.

[0095] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Furthermore, the effects described in the embodiments of the present invention are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention. [Explanation of symbols]

[0096] 1 document verification system, 2 terminal, 3 server, 20 extraction unit, 21 tamper verification unit, 30 certificate verification unit, 31 module allocation unit, 200 certificate data, 210 public key certificate, 220 revocation list, 230 verification time, 300 trusted certificate, 400 module

Claims

1. A document verification system for verifying a signature of an electronic document, comprising: The server includes an allocation unit that allocates a predetermined module to a terminal, the terminal includes an extracting unit that operates the assigned module to extract certificate data based on the electronic document; the server includes a certificate verification unit that verifies the extracted certificate data; the terminal includes a tampering verification unit that operates the assigned module to verify tampering of the electronic document; A document verification system comprising:

2. 2. The document verification system according to claim 1, wherein the assigned module operates in a Web browser.

3. 2. The document verification system according to claim 1, wherein the module operating on the server is configured with a Web component and / or a Web API.

4. the certificate data includes a public key certificate; 2. The document verification system according to claim 1, wherein the certificate verification unit verifies the public key certificate based on a trusted certificate.

5. the certificate data includes information regarding a public key certificate and a revocation list; 2. The document verification system according to claim 1, wherein the certificate verification unit verifies the public key certificate based on information related to the revocation list.

6. The extraction unit further extracts information regarding a verification time, 6. The document verification system according to claim 4, wherein the certificate verification unit verifies the public key certificate based on information relating to the verification time.

7. A document verification method executed by a document verification system for verifying a signature of an electronic document, comprising: A server assigns a predetermined module to a terminal; the terminal operates the assigned module to extract certificate data based on the electronic document; the server verifying the extracted certificate data; The terminal operates the assigned module to verify whether the electronic document has been tampered with; 1. A document verification method comprising:

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