Patent Publication Number: US-2020296253-A1

Title: Information processing apparatus, information processing system, and non-transitory computer readable medium storing information processing program for verifying an electronic signature

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2019-044307 filed Mar. 11, 2019. 
     BACKGROUND 
     (i) Technical Field 
     The present invention relates to an information processing apparatus, an information processing system, and a non-transitory computer readable medium storing an information processing program. 
     (ii) Related Art 
     JP2007-087322A proposes a workflow system, a server apparatus, a processing method, and a program capable of performing processing as a workflow process even in a case where an electronic form to be processed in a workflow is printed. More specifically, a workflow system, which includes screen formation data for forming an electronic form input screen and performs predetermined processing based on an electronic form in a case where input information is input from the input screen, is proposed. The workflow system includes paper form management means for generating paper layout information in a case where the input screen based on the screen formation data is formed in a paper form, print processing means for printing the input screen as a paper form based on the paper layout information together with an identification ID for identifying the electronic form, an image input device for inputting an image of a handwritten paper form, and paper flow processing means for extracting writing information from an image of an input paper form. The extracted writing information is converted into electronic writing information, and the electronic writing information is input to an electronic form corresponding to an identification ID. 
     Further, in JP2014-535216A, in a case where a user as a signer receives a hardcopy (for example, paper) document to be signed, the signer captures an image of the document to be signed using a camera of a mobile device. In this regard, a technique of allowing the signer to import the captured image to an electronic signature service for at least one of signing by another user, storing, or transmitting, is proposed. 
     SUMMARY 
     In a case where the imported image is transmitted and received to and from a user who is not registered in the electronic signature service, when the imported image is printed on paper, the electronic signature may not be verified. Aspects of non-limiting embodiments of the present disclosure relate to an information processing apparatus, an information processing system, and a non-transitory computer readable medium storing an information processing program capable of verifying an electronic signature even in a case where there is a user who is not registered in the electronic signature service. 
     Aspects of certain non-limiting embodiments of the present disclosure overcome the above disadvantages and/or other disadvantages not described above. However, aspects of the non-limiting embodiments are not required to overcome the disadvantages described above, and aspects of the non-limiting embodiments of the present disclosure may not overcome any of the disadvantages described above. 
     According to an aspect of the present disclosure, there is provided an information processing apparatus including: a calculation unit that calculates a hash value of an original image represented by electronic information to which an electronic signature is added in advance; and a storage unit that stores image information representing the original image and the hash value calculated by the calculation unit in association with the electronic information. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiment(s) of the present invention will be described in detail based on the following figures, wherein: 
         FIG. 1  is a diagram illustrating a schematic configuration of an information processing system according to an exemplary embodiment; 
         FIG. 2  is a block diagram illustrating a main configuration of an electrical system of an image forming apparatus according to the exemplary embodiment; 
         FIG. 3  is a block diagram illustrating a main configuration of an electrical system of each of an information processing terminal and a cloud server according to the exemplary embodiment; 
         FIG. 4  is a functional block diagram illustrating a detailed functional configuration of a signature management service provided by the cloud server of the information processing system according to the exemplary embodiment; 
         FIG. 5  is a diagram illustrating an example of information stored in a document management DB; 
         FIG. 6  is a diagram illustrating an example of resource information stored in a resource management DB; 
         FIG. 7  is a diagram for explaining a use example of the signature management service in a case where an electronic signature is added; 
         FIG. 8  is a diagram illustrating an example of a document registration screen; 
         FIG. 9  is a diagram illustrating how electronic information to which an electronic signature is added is delivered to a third party and another company user as a third party who is not registered in a cloud service and does not have an account is allowed to verify the electronic signature; 
         FIG. 10  is a flowchart illustrating an example of a flow of processing performed by the information processing terminal in a case where a user operates the information processing terminal to use the signature management service provided by the cloud server of the information processing system according to the exemplary embodiment; 
         FIG. 11  is a diagram illustrating an example of a screen for generating an image with a two-dimensional barcode; 
         FIG. 12  is a flowchart illustrating an example of a flow of processing performed by an authentication service provided by the cloud server of the information processing system according to the exemplary embodiment; 
         FIG. 13  is a flowchart illustrating an example of a flow of processing performed by the signature management service in a case where a user uses the signature management service provided by the cloud server of the information processing system according to the exemplary embodiment; 
         FIG. 14  is a sequence diagram for explaining processing performed in the information processing system according to the exemplary embodiment; 
         FIG. 15  is a diagram illustrating a way of requesting the signature management service to perform verification by reading a two-dimensional barcode using a camera or the like of a mobile terminal; 
         FIG. 16  is a flowchart illustrating an example of processing performed by a mobile terminal of the information processing system according to the exemplary embodiment in a case of verifying whether or not a received document with signature verification location information is a specified correct document; 
         FIG. 17  is a flowchart illustrating an example of a flow of processing performed by the cloud server of the information processing system according to the exemplary embodiment in a case where the mobile terminal accesses, using a URL indicated by a two-dimensional barcode, the signature management service provided by the cloud server; 
         FIG. 18  is a diagram illustrating a way in which signing and sealing is performed by another user as a third party on a predetermined area of paper, on which an image representing a document with signature verification location information is formed, and the signed and sealed paper is returned to a registered user by post or like; 
         FIG. 19  is a diagram illustrating away in which a document obtained by reading and computerizing the signed and sealed paper by the image forming apparatus is registered in the signature management service; 
         FIG. 20  is a flowchart illustrating an example of a flow of processing performed by the image forming apparatus of the information processing system according to the exemplary embodiment in a case where the document obtained by reading and computerizing the signed and sealed paper is registered in the signature management service; and 
         FIG. 21  is a flowchart illustrating an example of a flow of processing performed by the cloud server in a case where the signature management service receives the document obtained by reading and computerizing the signed and sealed paper by the image forming apparatus. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, an example of an exemplary embodiment will be described in detail with reference to the accompanying drawings. In the exemplary embodiment, an information processing system in which a plurality of image forming apparatuses, a plurality of information processing terminals, a wireless base station  17 , and a cloud server are connected to each other via a communication line such as a network will be described as an example.  FIG. 1  is a diagram illustrating a schematic configuration of an information processing system  10  according to the exemplary embodiment. 
     As illustrated in  FIG. 1 , the information processing system  10  according to the exemplary embodiment includes a plurality of image forming apparatuses  12   a ,  12   b , a plurality of information processing terminals  14   a ,  14   b , a wireless base station  17 , and a cloud server  16 . In a case where there is no need to distinguish the image forming apparatuses  12   a ,  12   b , and the information processing terminals  14   a ,  14   b , alphabets at the end of the numerals may be omitted. Further, in the exemplary embodiment, an example in which the plurality of image forming apparatuses  12   a ,  12   b , and information processing terminals  14   a ,  14   b , . . . are included will be described. On the other hand, at least one image forming apparatus  12  and at least one information processing terminal  14  may be included. Further, the image forming apparatus  12  corresponds to an image generation apparatus, the information processing terminal  14  corresponds to a terminal apparatus, and the cloud server  16  corresponds to an information processing apparatus. 
     The image forming apparatus  12 , the information processing terminal  14 , the wireless base station  17 , and the cloud server  16  are connected to each other via a communication line  18  such as a local area network (LAN), a wide area network (WAN), the Internet, or an intranet. Thus, various data can be transmitted and received between the image forming apparatus  12 , the information processing terminal  14 , the wireless base station  17 , and the cloud server  16  via the communication line  18 . Further, a mobile terminal  19  is wirelessly connected to the wireless base station  17 , and thus various data can be transmitted and received between the mobile terminal  19  and each apparatus. 
       FIG. 2  is a block diagram illustrating a main configuration of an electrical system of the image forming apparatus  12  according to the exemplary embodiment. 
     As illustrated in  FIG. 2 , the image forming apparatus  12  according to the exemplary embodiment includes a control unit  20  including a central processing unit (CPU)  20 A, a read only memory (ROM)  20 B, and a random access memory (RAM)  20 C. The CPU  20 A controls the entire operation of the image forming apparatus  12 . The RAM  20 C is used as a work area or the like when the CPU  20 A executes various programs. The ROM  20 B stores various control programs and various parameters in advance. In the image forming apparatus  12 , the components of the control unit  20  are electrically connected to each other via a system bus  42 . 
     On the other hand, the image forming apparatus  12  according to the exemplary embodiment includes a hard disk drive (HDD)  26  that stores various data such as user information, setting parameters, and defect information, application programs, and the like. Further, the image forming apparatus  12  includes a display control unit  28  that is connected to a user interface  22  and controls display of various operation screens on a display of the user interface  22 . Further, the image forming apparatus  12  includes an operation input detection unit  30  that is connected to the user interface  22  and detects an operation instruction which is input via the user interface  22 . In the image forming apparatus  12 , the HDD  26 , the display control unit  28 , and the operation input detection unit  30  are electrically connected to the system bus  42 . In the image forming apparatus  12  according to the exemplary embodiment, the HDD  26  is used as a memory unit. On the other hand, the present disclosure is not limited thereto, and a non-volatile memory unit such as a flash memory may be used. 
     Further, the image forming apparatus  12  according to the exemplary embodiment includes a read control unit  32 , which controls a read operation of an optical image by a document read unit  44  and a document transport operation by a document transport unit, and an image forming control unit  34 , which controls image forming processing by an image forming unit  24  and transport of paper to the image forming unit  24  by a transport unit  25 . Further, the image forming apparatus  12  includes a communication line interface (I/F) unit  36  that is connected to the communication line  18  and transmits and receives communication data to and from other external apparatuses such as the cloud server  16  connected to the communication line  18 . Further, the image forming apparatus includes a facsimile interface (I/F) unit  38  that is connected to a telephone line (not illustrated) and transmits and receives facsimile data to and from a facsimile machine connected to the telephone line. Further, the image forming apparatus  12  includes a transmission/reception control unit  40  that controls transmission/reception of facsimile data via the facsimile I/F unit  38 . In the image forming apparatus  12 , the transmission/reception control unit  40 , the read control unit  32 , the image forming control unit  34 , the communication line I/F unit  36 , the facsimile I/F unit  38 , and a log collection unit are electrically connected to the system bus  42 . 
     With the configuration, in the image forming apparatus  12  according to the exemplary embodiment, the CPU  20 A accesses each of the RAM  20 C, the ROM  20 B, and the HDD  26 . Further, in the image forming apparatus  12 , the CPU  20 A controls display of information such as operation screens and various messages on a display  22 A of the user interface  22  via the display control unit  28 . Further, in the image forming apparatus  12 , the CPU  20 A controls operations of the document read unit  44  and the document transport unit via the read control unit  32 . Further, in the image forming apparatus  12 , the CPU  20 A controls operations of the image forming unit  24  and the transport unit via the image forming control unit  34 , and controls transmission and reception of communication data via the communication line I/F unit  36 . Further, in the image forming apparatus  12 , the CPU  20 A controls transmission/reception of facsimile data via the facsimile I/F unit  38  by the transmission/reception control unit  40 . Further, in the image forming apparatus  12 , the CPU  20 A recognizes operation contents of the user interface  22  based on operation information detected by the operation input detection unit  30 , and executes various controls based on the operation contents. 
     Next, a main configuration of an electric system of each of the information processing terminal  14  and the cloud server  16  according to the exemplary embodiment will be described.  FIG. 3  is a block diagram illustrating a main configuration of an electrical system of each of the information processing terminal  14  and the cloud server  16  according to the exemplary embodiment. The information processing terminal  14  and the cloud server  16  are basically configured with general computers. Thus, in this description, the cloud server  16  will be representatively described. 
     As illustrated in  FIG. 3 , the cloud server  16  according to the exemplary embodiment includes a CPU  16 A, a ROM  16 B, a RAM  16 C, an HDD  16 D, a keyboard  16 E, a display  16 F, and a communication line interface (I/F) unit  16 G. The CPU  16 A controls the entire operation of the cloud server  16 . The ROM  16 B stores various control programs and various parameters in advance. The RAM  16 C is used as a work area or the like when the CPU  16 A executes various programs. The HDD  16 D stores various data, application programs, and the like. The keyboard  16 E is used to input various information. The display  16 F is used to display various information. The communication line I/F unit  16 G is connected to the communication line  18 , and transmits and receives various data to and from other apparatuses connected to the communication line  18 . The units of the cloud server  16  are electrically connected to each other by a system bus  16 H. In the cloud server  16  according to the exemplary embodiment, the HDD  16 D is used as a memory unit. On the other hand, the present disclosure is not limited thereto, and a non-volatile memory unit such as a flash memory may be used. 
     With the configuration, in the cloud server  16  according to the exemplary embodiment, the CPU  16 A accesses each of the ROM  16 B, the RAM  16 C, and the HDD  16 D, acquires various data via the keyboard  16 E, and displays various information on the display  16 F. Further, in the cloud server  16 , the CPU  16 A controls transmission and reception of communication data via the communication line I/F unit  16 G. 
     Similar to the information processing terminal  14  and the cloud server  16 , the mobile terminal  19  is basically configured with a computer including a CPU, a ROM, a RAM, and the like, and thus a detailed description thereof will be omitted. 
     In the information processing system  10  with the above-described configuration, the information processing terminal  14 , the image forming apparatus  12 , and the mobile terminal  19  can use a cloud service provided by the cloud server  16 . As an example of the cloud service, in the exemplary embodiment, an example in which the cloud server  16  provides a signature management service and an authentication service as an example will be described. In the exemplary embodiment, an example in which the single cloud server  16  provides the signature management service and the authentication service as a cloud service will be described. On the other hand, the services may be respectively provided from different cloud servers  16 . 
     In the signature management service, a hash value of electronic information is calculated, signature information encrypted using a private key is added to the original electronic information, as an electronic signature, and the calculated hash value is stored in a database or the like. In addition, in a case of performing signature verification, the signature verification is performed by decrypting the signature information added to the electronic information using a public key and comparing whether the hash value of the electronic information stored in the database or the like and the decrypted hash value are identical. As the electronic information, at least one of document information created by a document creation application program or the like or image information obtained by reading an image by the image forming apparatus  12  or the like is used. 
     On the other hand, in the authentication service, authentication is performed in a case where a cloud service such as a signature management service is provided. For example, a user is registered in advance, and user identification information (hereinafter, referred to as a user ID) and a password are set and stored in a database or the like. In a case of using a cloud service such as a signature management service, authentication is performed as to whether or not the user is a registered user. 
       FIG. 4  is a functional block diagram illustrating a detailed functional configuration of a signature management service provided by the cloud server  16  of the information processing system  10  according to the exemplary embodiment. 
     In a case where the image forming apparatus  12  and the information processing terminal  14  access the cloud server  16 , a signature management service  50  may be used in cooperation with an authentication service  74 . 
     The signature management service  50  has functions of an information management unit  52 , a document processing unit  54 , a signature management unit  56 , a two-dimensional barcode generation unit  62 , an image analysis unit  64 , a notification processing unit  66 , and a data access unit  68 . 
     The information management unit  52  manages transmission and reception of information to and from the information processing terminal  14 , the image forming apparatus  12 , and the authentication service  74 . 
     The document processing unit  54  controls exchange of information between each unit so as to process the electronic information (for example, document information or image information) which is input. Further, the document processing unit  54  accesses a document management database (hereinafter, a database is referred to as DB)  70  and a resource management DB  72  via the data access unit  68 , and reads and writes resource identification information (hereinafter, referred to as a resource ID), a user ID, a hash value, image information, and the like. Further, in a case of delivering the electronic information stored in the document management DB  70  to the information processing terminal  14  or the image forming apparatus  12 , the document processing unit  54  stores the target electronic information in a shared area which is shared with a third party such as a file server. 
     The signature management unit  56  has functions of a signature adding unit  58  that adds an electronic signature and a signature verification unit  60  that verifies the electronic signature. 
     When electronic information is uploaded from a client such as the information processing terminal  14  or the image forming apparatus  12 , the signature adding unit  58  adds an electronic signature using a private key of a user. In the exemplary embodiment, the electronic signature is added using a public key encryption method as an example. Specifically, the signature adding unit  58  calculates a hash value of the electronic information, adds signature information encrypted using a private key to the electronic information, as an electronic signature, and stores the calculated hash value in the document management DB  70 . In addition, the signature adding unit  58  stores the calculated hash value in the resource management DB  72  in association with a resource ID, an uploaded user ID, and the like. 
     Further, the signature verification unit  60  verifies the electronic signature added to the electronic information. Specifically, the signature verification is performed by decrypting the signature information added to the electronic information using a public key and comparing whether the hash value, which is stored in the resource management DB  72  in association with the electronic information stored in the document management DB  70 , and the decrypted hash value are identical. 
     The two-dimensional barcode generation unit  62  generates a two-dimensional barcode including a uniform resource locator (URL) for signature verification, as an example of position information. 
     The image analysis unit  64  performs processing of confirming identity of images by calculating a hash value of an image by analyzing the image of the electronic information and comparing the calculated hash value with a hash value stored in the resource management DB  72 . Further, the image analysis unit  64  performs processing of updating the resource information stored in the resource management DB  72  using the calculated hash value of the image. 
     The notification processing unit  66  notifies various operation information and various information by transmitting an e-mail or the like to a related user. For example, in the exemplary embodiment, in a case where the document processing unit  54  stores target electronic information in a shared area which is shared with a third party such as a file server, the notification processing unit  66  notifies the storage location. 
     The document management DB  70  stores at least one of electronic information to which an electronic signature is added or electronic information to which an electronic signature is not added. For example, the document management DB  70  stores information as illustrated in  FIG. 5 .  FIG. 5  illustrates an example in which a document ID, a document name, a registered user, document information, an image, and the like are stored in association with each other. 
     The resource management DB  72  stores a resource ID, an uploaded user ID of a user, a hash value, image information, and the like in association with each other. For example, the resource management DB  72  stores resource information as illustrated in  FIG. 6 .  FIG. 6  illustrates an example in which a resource ID, a user ID, a hash value, image identification information (hereinafter, referred to as an image ID), and the like are stored in association with each other as resource information. 
     In addition, in a DB  76  accessed by the authentication service  74 , a user ID, a password, and the like are stored, and the information is used so as to authenticate a user. 
     The image analysis unit  64  corresponds to a calculation unit, the document management DB  70  and the resource management DB  72  correspond to a storage unit, the two-dimensional barcode generation unit  62  corresponds to an adding unit, the notification processing unit  66  corresponds to a notification unit, and the signature verification unit  60  corresponds to a verification unit. 
     Here, a use example of a signature management service provided by the cloud server  16  of the information processing system  10  with the configuration will be described. 
       FIG. 7  is a diagram for explaining a use example of the signature management service  50  in a case where an electronic signature is added.  FIG. 7  illustrates an example in which a paper document is read and computerized by the image forming apparatus  12  and an electronic signature is added to the document information. 
     First, the document read unit  44  of the image forming apparatus  12  is caused to read a paper document by a user, and a private key is set by a user. For example, a document registration screen illustrated in  FIG. 8  is displayed on the user interface  22  of the image forming apparatus  12 , and a document name, key information, and the like are set. Thereby, the paper document is computerized by the image forming apparatus  12 , and the document converted into image information is transmitted to the signature management service  50  provided by the cloud server  16 . In the signature management service  50 , the signature adding unit  58  calculates a hash value of the image information, encrypts signature information using the private key set by a user, adds the encrypted signature information to the image information, as an electronic signature, and stores the calculated hash value in the document management DB  70 . Further, the signature adding unit  58  stores the calculated hash value in the resource management DB  72  in association with a resource ID, an uploaded user ID, and the like. Thereby, the electronic information to which the electronic signature is added is accumulated in the document management DB  70 . 
     In  FIG. 7 , although an example in which a paper document is computerized and an electronic signature is added to the document information is described, the present disclosure is not limited thereto. For example, an electronic signature may be added to document information created by a user using the information processing terminal  14  or the like, and the document information to which the electronic signature is added may be stored in the document management DB  70 . That is, at least one of document information or image information is stored in the document management DB  70 , as electronic information. 
       FIG. 9  is a diagram illustrating how electronic information to which an electronic signature is added is delivered to a third party and another company user as a third party who is not registered in a cloud service and does not have an account is allowed to verify the electronic signature. 
     The electronic information to which the electronic signature is added, which is stored in the document management DB  70 , may be transmitted to another company user as a third party and requested to be signed and sealed. In this case, as illustrated in  FIG. 9 , even in a case where the electronic information to which the electronic signature is added is printed on paper, in order to make it possible to verify the electronic signature, the electronic signature is converted into a hash value of an image by adding a matrix-type two-dimensional barcode  80  representing a URL or the like for verifying the electronic signature to the electronic information, as location information, and the location information is stored in a shared area which is shared with a third party. The location information indicating a storage location is notified to another company user as a third party by an e-mail or the like. 
     Here, in a case where a user who is registered in the signature management service  50  delivers, as a document, the electronic information to which the electronic signature is added to another company user as a third party who is not registered in the signature management service  50  and does not have an account, specific processing performed by the information processing system  10  will be described. 
       FIG. 10  is a flowchart illustrating an example of a flow of processing performed by the information processing terminal  14  in a case where a user operates the information processing terminal  14  to use the signature management service  50  provided by the cloud server  16  of the information processing system  10  according to the exemplary embodiment. The processing of  FIG. 10  is started, for example, in a case where a user instructs starting of use of the signature management service  50  by operating the information processing terminal  14  or the like. 
     In step  100 , the CPU  14 A displays an input screen for inputting a user ID and a password, and the process proceeds to step  102 . 
     In step  102 , the CPU  14 A determines whether or not a user ID and a password are input. The CPU  14 A waits until the determination result is Yes, and the process proceeds to step  104 . In a case where there is another instruction while waiting, the CPU  14 A ends the process and executes instructed processing. 
     In step  104 , the CPU  14 A requests an issuance of an authorization token to use the signature management service by transmitting a user ID and a password to the authentication service  74 , and the process proceeds to step  106 . 
     In step  106 , the CPU  14 A determines whether or not an authorization token is received from the authentication service  74 . In a case where the determination result is No, that is, in a case where the authentication service  74  does not permit use of the signature management service  50 , the process proceeds to step  108 . 
     In a case where the determination result is Yes, the process proceeds to step  110 . 
     In step  108 , the CPU  14 A displays information indicating that use of the signature management service  50  is not permitted, on a display  14 F, and a series of processing is ended. 
     On the other hand, in step  110 , the CPU  14 A requests a document list of the document management DB  70 , that is, a list of the electronic information stored in the document management DB  70 , from the signature management service  50 , using the received authorization token, and the process proceeds to step  112 . 
     In step  112 , the CPU  14 A receives a requested document list from the signature management service  50 , and the process proceeds to step  114 . 
     In step  114 , the CPU  14 A displays a document list selection screen for selecting a document to be delivered to a third party from the document list, and the process proceeds to step  116 . For example, as a document list selection screen, an image generation screen with a two-dimensional barcode  80  as illustrated in  FIG. 11  is displayed. The example of  FIG. 11  illustrates an example in which electronic information corresponding to a document of which the document name is “12345” is selected and a preview image of the selected electronic information is displayed. 
     In step  116 , the CPU  14 A determines whether or not a document is selected. The CPU  14 A waits until the determination result is Yes, and the process proceeds to step  118 . 
     In step  118 , the CPU  14 A determines whether or not there is signature verification location information for signature verification. In this determination, it is determined whether or not location information such as a two-dimensional barcode representing location information such as a URL of a signature verification site is added to the selected document information. In a case where the determination result is No, the process proceeds to step  120 , and in a case where the determination result is Yes, the process proceeds to step  124 . 
     In step  120 , the CPU  14 A requests the signature management service  50  to add signature verification location information to the document information, and the process proceeds to step  122 . 
     In step  122 , the CPU  14 A determines whether or not document information with signature verification location information, to which signature verification location information is added, is received. 
     The CPU  14 A waits until the determination result is Yes, and the process proceeds to step  124 . 
     In step  124 , the CPU  14 A stores the electronic information corresponding to the selected document, to which the signature verification location information is added, in a predetermined shared area that may be viewed by a third party, and the process proceeds to step  126 . The shared area may be a shared area of a file server which is shared with a third party, may be an area in the document management DB  70 , or may be another area. 
     In step  126 , the CPU  14 A notifies the information processing terminal  14  or the mobile terminal  19  of a third party that the electronic information is stored, and the series of processing is ended. 
     Next, authentication processing by the authentication service, which is performed in a case where a user operates the information processing terminal  14  to use the signature management service, will be described.  FIG. 12  is a flowchart illustrating an example of a flow of processing performed by the authentication service  74  provided by the cloud server of the information processing system  10  according to the exemplary embodiment. The processing of  FIG. 12  is started in a case where authentication is requested by a user via the information processing terminal  14  or the like. Specifically, the processing of  FIG. 12  is started in a case where an issuance of an authorization token is requested in step  104  of  FIG. 10 . 
     In step  200 , the authentication service  74  receives a user ID and a password from the information processing terminal  14  or the like, and the process proceeds to step  202 . 
     In step  202 , the authentication service  74  requests the signature management service  50  to verify whether a user corresponding to the received user ID and password is a registered user, and the process proceeds to step  204 . 
     In step  204 , the authentication service  74  receives a verification result from the signature management service  50 , and the process proceeds to step  206 . 
     In step  206 , the authentication service  74  determines whether or not the received verification result indicates that the user is a registered user and the signature management service  50  is permitted for the registered user. In a case where the determination result is No, the process proceeds to step  208 , and in a case where the determination result is Yes, the process proceeds to step  210 . 
     In step  208 , the authentication service  74  notifies the information processing terminal  14  that the signature management service  50  is not permitted, and a series of processing is ended. 
     On the other hand, in step  210 , the authentication service  74  issues an authorization token to the information processing terminal  14 , and the series of processing is ended. Thereby, the information processing terminal  14  is permitted to use the signature management service  50  using the authorization token. 
     Next, in a case where a user operates the information processing terminal  14  or the like to use the signature management service  50 , processing performed by the signature management service  50  will be described.  FIG. 13  is a flowchart illustrating an example of a flow of processing performed by the signature management service  50  in a case where a user uses the signature management service  50  provided by the cloud server  16  of the information processing system  10  according to the exemplary embodiment. The processing of  FIG. 13  is started in a case where information is received from the authentication service  74  or the information processing terminal  14 . 
     In step  300 , the information management unit  52  determines whether or not the received information is an authorization verification request from the authentication service  74 . In a case where the determination result is Yes, the process proceeds to step  302 , and in a case where the determination result is No, the process proceeds to step  306 . 
     In step  302 , the information management unit  52  performs verification of user registration by verifying the user ID and password received by the authentication service  74 , and the process proceeds to step  304 . 
     In step  304 , the information management unit  52  transmits a verification result as a response to the authentication service  74 , and the process proceeds to step  306 . 
     In step  306 , the information management unit  52  determines whether or not the received information is a document list request with an authorization token from the information processing terminal  14  or the like. In a case where the determination result is Yes, the process proceeds to step  312 , and in a case where the determination result is No, the process proceeds to step  308 . 
     In step  308 , the information management unit  52  determines whether or not the received information is other information other than an authorization verification request and a document list request with an authorization token. In a case where the determination result is Yes, a series of processing is ended, and processing corresponding to the received other information is performed. In a case where the determination result is No, the process proceeds to step  310 . 
     In step  310 , the information management unit  52  notifies the request source that the document list request is not permitted, and the series of processing is ended. 
     On the other hand, in step  312 , the document processing unit  54  acquires a requested document list from the document management DB  70  via the data access unit  68  and transmits the acquired document list as a response, and the process proceeds to step  314 . 
     In step  314 , the information management unit  52  determines whether or not a document request with an authorization token is performed. In a case where the determination result is No, the process proceeds to step  310 , and in a case where the determination result is Yes, the process proceeds to step  316 . 
     In step  316 , the document processing unit  54  acquires electronic information corresponding to the requested document from the document management DB  70  via the data access unit  68  and transmits the acquired document as a response, and the process proceeds to step  318 . 
     In step  318 , it is determined whether or not a document with signature verification location information is requested. In a case where the determination result is No, the series of processing is ended, and in a case where the determination result is Yes, the process proceeds to step  320 . 
     In step  320 , the two-dimensional barcode generation unit  62  generates signature verification location information, and adds the generated signature verification location information to the document. Then, the process proceeds to step  322 . For example, the two-dimensional barcode generation unit generates a two-dimensional barcode  80  including a URL for signature verification, as signature verification location information, and adds the two-dimensional barcode  80  to a document image. 
     In step  322 , the image analysis unit  64  calculates a hash value of an image of the electronic information by analyzing the image of the electronic information, and the process proceeds to step  324 . The hash value of the image is calculated by calculating a hash value of an image in a predetermined area which is not changed by post-processing other than an area which is signed and sealed in post-processing and an area to which the location information is added. 
     In step  324 , the data access unit  68  updates a resource DB so as to store the calculated hash value in correspondence to the electronic information, and the process proceeds to step  326 . 
     In step  326 , the notification processing unit  66  transmits the document with signature verification location information, as a response, to the request source such as the information processing terminal  14  and the like, and the series of processing is ended. 
     As described above, in the information processing system  10  according to the exemplary embodiment, as illustrated in  FIG. 14 , processing by each unit is performed. 
     That is, in processing of step  100  to step  104 , in a case where a registered user (illustrated as a registrant in  FIG. 14 ) inputs a user ID and a password by operating the information processing terminal  14  or the like, an authorization token issuance request is transmitted to the authentication service  74 . 
     In processing of step  200  to step  202 , in a case of receiving the authorization token issuance request, the authentication service  74  transmits a verification request of the user ID and the password to the signature management service  50 . 
     In processing of step  300  to step  302 , in a case of receiving the verification request from the authentication service  74 , the signature management service  50  verifies whether a user corresponding to the user ID and the password is registered, and transmits a verification result to the authentication service  74 . 
     In processing of step  204  to step  210 , in a case where the verification result is received from the signature management service  50  and the received verification result indicates that the user is a registered user, the authentication service  74  issues an authorization token to the information processing terminal  14  or the like of the registrant. In a case where the received verification result indicates that the user is not a registered user, the authentication service  74  notifies the information processing terminal  14  that the signature management service  50  is not permitted. 
     Subsequently, in processing of step  106  to step  112 , in a case where an authorization token is acquired, the registered user requests a document list to the signature management service  50  using the authorization token. 
     In processing of step  306  to step  312 , the signature management service  50  confirms that the user is a registered user, using the authorization token, and transmits a requested document list as a response. 
     In processing of step  114  to step  122 , the registered user selects a document from the document list acquired from the signature management service  50 , and requests the document to the signature management service  50 . At this time, in a case where signature verification location information is not added to the document, as illustrated by a dotted line in  FIG. 14 , signature verification location information is requested. 
     In processing of step  314  to step  326 , the signature management service  50  transmits a document with signature verification location information as a response. In a case where signature verification location information is not added to the document and signature verification location information is requested from the registrant, the two-dimensional barcode generation unit  62  generates signature verification location information, adds the generated signature verification location information to the document, and transmits the document with signature verification location information to the registrant, as a response. 
     The registered user confirms the document with signature verification location information. In processing of step  124  to step  126 , in a case where the registered user wants to transmit the document with signature verification location information to another user as a third party, the registered user stores the target document with signature verification location information in a shared area which is shared with the third party, and notifies the third party that the document is stored. 
       FIG. 10  to  FIG. 14  illustrate an example in which the authentication service  74  transmits a verification request to the signature management service  50  in a case where a registered user requests an issuance of an authorization token to the authentication service  74 . On the other hand, the present disclosure is not limited thereto. For example, in a case where a registered user requests an issuance of an authorization token to the authentication service  74 , the authentication service  74  may issue an authorization token without requesting the signature management service  50  to verify the user, and in a case where a user requests the signature management service  50  using an authorization token, the signature management service  50  may request the authentication service  74  to verify the authorization token. 
     On the other hand, in a case where a notification is received from a registered user, another user as a third party confirms the shared area, and causes the image forming apparatus  12  or the like to form and output an image represented by the document with signature verification location information, on paper. On the output paper, a two-dimensional barcode  80  as signature verification location information is formed together with the image of the document. 
     In a case of verifying whether or not the received document with signature verification location information is a correct document, as illustrated in  FIG. 15 , another user as a third party requests the signature management service  50  to perform verification by causing a camera of the mobile terminal  19  to read the two-dimensional barcode  80  formed on the paper. 
     Here, an example of processing performed by the mobile terminal  19  in a case where a third party requests document verification as to whether or not the received document with signature verification location information is a specified correct document will be described.  FIG. 16  is a flowchart illustrating an example of processing performed by the mobile terminal  19  of the information processing system  10  according to the exemplary embodiment in a case of verifying whether or not the received document with signature verification location information is a specified correct document. The processing of  FIG. 16  is started, for example, in a case where an instruction for capturing a two-dimensional barcode  80  is performed by the mobile terminal  19 . 
     In step  400 , the mobile terminal  19  reads the two-dimensional barcode  80  formed on the paper, and the process proceeds to step  402 . 
     In step  402 , the mobile terminal  19  accesses a URL indicated by the two-dimensional barcode  80 , and the process proceeds to step  404 . 
     In step  404 , the mobile terminal  19  displays a document verification request screen provided by the signature management service  50 , and the process proceeds to step  406 . As the document verification request screen to be displayed, for example, a screen for inputting a public key for specifying a verification target is displayed. 
     In step  406 , the mobile terminal  19  determines whether or not there is a public key. In this determination, it is determined whether or not a public key is input on the document verification request screen. In a case where the determination result is No, the process proceeds to step  408 , and in a case where the determination result is Yes, the process proceeds to step  410 . 
     In step  408 , the mobile terminal  19  notifies the third party who uses the mobile terminal  19  of a fact that the document verification is not possible by displaying the fact, and a series of processing is ended. 
     In step  410 , the mobile terminal  19  requests the signature management service  50  to verify the document using a public key, and the process proceeds to step  412 . 
     In step  412 , the mobile terminal  19  receives a verification result from the signature management service  50  and displays the received verification result, and the series of processing is ended. 
     Next, an example of processing performed by the signature management service  50  in a case where the mobile terminal  19  accesses a URL indicated by the two-dimensional barcode  80  will be described.  FIG. 17  is a flowchart illustrating an example of a flow of processing performed by the cloud server  16  of the information processing system  10  according to the exemplary embodiment in a case where the mobile terminal  19  accesses, using a URL indicated by the two-dimensional barcode  80 , the signature management service  50  provided by the cloud server  16 . In the exemplary embodiment, a case where a website designated by a URL including the two-dimensional barcode is a website provided by the signature management service  50  will be described as an example. In a case where a website designated by a URL including the two-dimensional barcode is a website provided by another cloud server or the like, not the signature management service  50  but another cloud server or another cloud service performs processing of  FIG. 17 . 
     In step  500 , the signature verification unit  60  transmits a document verification request screen to the mobile terminal  19 , and the process proceeds to step  502 . Thereby, the document verification request screen is displayed on the mobile terminal  19  as described in step  404 . 
     In step  502 , the signature verification unit  60  determines whether or not a verification request is received. In this determination, it is determined whether or not a public key is input and a verification request is performed as described in step  406  to step  410 . The signature verification unit  60  waits until the determination result is Yes, and the process proceeds to step  504 . 
     In step  504 , the signature verification unit  60  verifies, using the public key, whether or not the document with signature verification location information is a specified document, and the process proceeds to step  506 . That is, the signature verification unit  60  verifies whether the document with the two-dimensional barcode captured by the mobile terminal  19  is a correct document. Specifically, in a case where the input public key is a correct public key, the signature verification unit  60  determines that the document with the two-dimensional barcode is a correct document. 
     In step  506 , the notification processing unit  66  transmits, as a response, the verification result of step  504  to the mobile terminal  19  as a request source, and a series of processing is ended. 
     In addition, as illustrated in  FIG. 18 , signing and sealing is performed by another user as a third party on a predetermined area of the paper, on which the image representing the document with signature verification location information is formed, and the signed and sealed paper is returned to the registered user by post or like. The signed and sealed paper may be computerized by being read by the image forming apparatus  12  or the like, and may be transmitted to the registered user using an electronic mail or the like. 
     In a case where the registered user receives the signed and sealed paper by post or like, as illustrated in  FIG. 19 , the signed and sealed paper is computerized by being read by the image forming apparatus  12 , and is registered in the signature management service  50 . 
     Here, a specific example of processing performed by the image forming apparatus  12  in a case where the document obtained by reading and computerizing the signed and sealed paper is registered in the signature management service  50  will be described.  FIG. 20  is a flowchart illustrating an example of a flow of processing performed by the image forming apparatus  12  of the information processing system  10  according to the exemplary embodiment in a case where the document obtained by reading and computerizing the signed and sealed paper is registered in the signature management service  50 . The processing of  FIG. 20  is started in a case where an instruction for registering the document obtained by reading and computerizing the signed and sealed paper in the signature management service  50  is performed. The document obtained by reading and computerizing the signed and sealed paper corresponds to additional image information. In a case where the registered user receives the document obtained by computerizing the signed and sealed paper by an email or the like, the information processing terminal  14  performs processing other than step  604  of  FIG. 20 . 
     In step  600 , the CPU  20 A displays a login screen for the signature management service  50  on the user interface  22 , and the process proceeds to step  602 . 
     In step  602 , the CPU  20 A determines whether or not the registered user is logged in. In a case where the determination result is No, a series of processing is ended, and in a case where the determination result is Yes, the process proceeds to step  604 . 
     In step  604 , the CPU  20 A controls the document read unit  44  to read the document transmitted from a third party, that is, the signed and sealed paper, and the process proceeds to step  606 . 
     In step  606 , the CPU  20 A transmits the read result, which is the document obtained by reading and computerizing the signed and sealed paper, to the signature management service  50 , and the series of processing is ended. 
     Next, an example of processing performed by the cloud server  16  in a case where the signature management service  50  receives the document obtained by reading and computerizing the signed and sealed paper by the image forming apparatus  12  will be described.  FIG. 21  is a flowchart illustrating an example of a flow of processing performed by the cloud server  16  in a case where the signature management service  50  receives the document obtained by reading and computerizing the signed and sealed paper by the image forming apparatus  12 . The processing of  FIG. 21  is started in a case where the image forming apparatus  12  transmits the read result to the signature management service  50  in step  606 . 
     In step  700 , the document processing unit  54  receives the read result from the image forming apparatus  12 , and the process proceeds to step  702 . The processing of step  700  corresponds to processing by a reception unit. 
     In step  702 , the image analysis unit  64  extracts an image in a predetermined area other than an area to which signature verification location information such as a two-dimensional barcode  80  is added and an area which is signed and sealed by a third party, and the process proceeds to step  704 . 
     In step  704 , the image analysis unit  64  calculates a hash value of the extracted image, and the process proceeds to step  706 . 
     In step  706 , the data access unit  68  acquires a hash value of the document stored in the resource management DB  72 , and compares the acquired hash value with the calculated hash value. Then, the process proceeds to step  708 . 
     In step  708 , the image analysis unit  64  determines whether or not the acquired hash value and the calculated hash value are identical. In a case where the determination result is No, the process proceeds to step  710 , and in a case where the determination result is Yes, the process proceeds to step  712 . 
     In step  710 , the notification processing unit  66  notifies the image forming apparatus  12  that the document obtained by reading and computerizing the signed and sealed paper may be an illegal document, and a series of processing is ended. Thereby, the image forming apparatus  12  displays that the document obtained by reading and computerizing the signed and sealed paper may be an illegal document, on the user interface  22 . 
     In step  712 , the data access unit  68  updates the image information stored in the resource management DB  72  with the image information which is read, and the series of processing is ended. The processing of step  712  corresponds to processing by an updating unit. 
     In the exemplary embodiment, although the two-dimensional barcode  80  including a URL or the like is described as an example of signature verification location information, the present disclosure is not limited thereto. For example, the URL itself may be added to the image. Alternatively, a one-dimensional barcode including a URL or the like may be added to the image. 
     In addition, although the processing performed by the cloud server  16  according to the exemplary embodiment is described as processing performed by software, the processing by the cloud server  16  may be performed by dedicated hardware or by a combination of software and hardware. The processing to be performed by the cloud server  16  may be distributed by being stored in a storage medium as a program. 
     The present invention is not limited to the exemplary embodiment, and various modifications may be made without departing from the spirit of the inventions. 
     The foregoing description of the exemplary embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.