Patent Publication Number: US-11645420-B2

Title: Non-transitory computer-readable storage medium and communication device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2020-143265, filed on Aug. 27, 2020, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The embodiments discussed herein are related to a non-transitory computer-readable storage medium, a communication device, a communication method, and a communication system. 
     BACKGROUND 
     A distributed ID distribution platform that safely distributes decentralized identity information (hereinafter, may be referred to as ID information) as a digital certificate with agreement with the identical person has attracted more attention. From viewpoint of security and personal information protection, regarding the ID distribution platform, it is desirable not to distribute the ID information of the user (user information) in a format that can be read by a third party. 
     Regarding the ID distribution platform, there is a case where the user confirms whether or not the user information of the user himself/herself is correctly registered by a business operator. At this time, the business operator anonymizes and distributes the user information. For example, the business operator hashes the user information managed by the business operator himself/herself using a hash function and transfers the calculated hash value and the hash function to the user. The user hashes the user information of the user himself/herself using the hash function, compares the received hash value with the calculated hash value, and confirms whether or not the managed user information is correct. 
     Techniques related to anonymization such as a digital certificate are described in the following prior art documents. 
     Examples of the related art include Japanese Laid-open Patent Publication No. 2020-47308, Japanese Laid-open Patent Publication. No. 2019-141723, Japanese Laid-open Patent Publication No. 2019-46036, U.S. Laid-open Patent Publication No. 2014-0047551, and U.S. Laid-open Patent Publication No. 2019-0251290. 
     SUMMARY 
     According to an aspect of the embodiments, a non-transitory computer-readable storage medium storing a program that causes a processor included in a business operator&#39;s terminal to execute a process, the process includes conversion processing that converts user information acquired from an user into a management format and obtains converted user information; and confirmation request processing that calculates a first hash value obtained by hashing the converted user information with a first hash function, transmits a confirmation request including the first hash value, the first hash function, and conversion content of the conversion to the user, and requests the user to confirm validity of the user information managed. 
     The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a diagram illustrating an exemplary configuration of a communication system  1 ; 
         FIG.  2    is a diagram illustrating an exemplary configuration of a business operator&#39;s terminal  200 ; 
         FIG.  3    is a diagram illustrating an exemplary configuration of a user terminal  100 ; 
         FIG.  4    is a diagram illustrating an example of a sequence of user information registration confirmation processing; 
         FIG.  5    is a diagram illustrating an example of a processing flowchart of user information registration processing S 100 ; 
         FIG.  6    is a diagram illustrating an example of a processing flowchart of registration content confirmation processing S 200 ; 
         FIG.  7    is a diagram illustrating an example of the user information registration confirmation processing; 
         FIG.  8    is a diagram illustrating an example of a processing flowchart of user information registration processing S 101 ; 
         FIG.  9    is a diagram illustrating an example of a processing flowchart of registration content confirmation processing S 201 ; 
         FIG.  10    is a diagram illustrating an example of user information registration confirmation processing according to a second embodiment; 
         FIG.  11    is a diagram illustrating an example of format conversion; and 
         FIG.  12    is a diagram illustrating an example of noise information. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In the related art, when the user information is registered to the business operator, there is a case where the user registers the user information in a format different from a format requested by the business operator, for example, notational fluctuation, insertion of extra characters and blanks, a format error, or the like. In this case, the business operator converts the user information into a format unique to the business operator and registers and manages the user information. Since a hash value of the user information of which the format has been converted is different from a hash value of the user information before the format is converted, although correct user information in a different format is actually managed, there is a case where the user determines that correct information is not managed. 
     Therefore, one disclosure provides a communication program, a communication device, a communication method, and a communication system that suppress wrong determination by a user in collation of user information using a hash value. 
     First Embodiment 
     A first embodiment will be described. 
     &lt;Exemplary Configuration of Communication System  1 &gt; 
       FIG.  1    is a diagram illustrating an exemplary configuration of a communication system  1 . The communication system  1  includes a user  10 , a user terminal  100 , business operators  20 - 1  to  20 - n  (n is integer), business operator&#39;s terminals  200 - 1  to  200 - n , and an ID distribution platform  300 . The communication system  1  is a system that registers user information including personal information such as an attribute of the user  10  to the business operators  20 - 1  to  20 - n  and uses the registered user information as a digital certificate. The user information is, for example, attribute information regarding an attribute such as the gender or an address of the user  10 . 
     The user  10  is, for example, an individual user who requests for registration of a digital certificate or issuance of a digital certificate or a user who uses a service. The user  10  uses the user terminal  100  and registers the user information to the business operators  20 - 1  to  20 - n.    
     The user terminal  100  is a communication device used by the user  10  and is, for example, a smartphone, a tablet terminal, a computer, or a server machine. The user terminal  100  registers the user information of the user  10  in the business operator&#39;s terminals  200 - 1  to  200 - n . The user terminal  100  communicates with the business operator&#39;s terminals  200 - 1  to  200 - n  via the ID distribution platform  300 . Furthermore, the user terminal  100  can communicate with the business operator&#39;s terminals  200 - 1  to  200 - n  without via the ID distribution platform  300 . 
     The business operators  20 - 1  to  20 - n  (hereinafter, may be referred to as business operator  20 ) are persons who issue certificates to the user  10  and are, for example, companies or public institutions. The public institution includes, for example, public institutions such as government offices, driver&#39;s license headquarters or educational institutions such as schools. Furthermore, the business operator  20  is a person who requests the user  10  to proof identity, and is, for example, a service provider or a service providing company that provides a service. 
     The business operator&#39;s terminals  200 - 1  to  200 - n  (hereinafter, may be referred to as business operator&#39;s terminal  200 ) are communication devices used by the business operator  20  and are, for example, computers or server machines. A business operator&#39;s terminal  200 - x  (x is integer) is used by a business operator  20 - x.  The business operator&#39;s terminal  200  executes processing regarding the user information and the digital certificate such as registration or confirmation request of the user information. The business operator&#39;s terminal  200  communicates with the user terminal  100  and the other business operator&#39;s terminal  200  via the ID distribution platform  300  Furthermore, the business operator&#39;s terminal  200  can communicate with the user terminal  100  without via the ID distribution platform  300 . 
     The ID distribution platform  300  is a communication network (second network) that transmits or receives digital certificates, confirms registration of the user information to the user  10 , or the like. Because the ID distribution platform  300  distributes personal information (user information) such as a digital certificate, the ID distribution platform  300  desirably has higher security (confidentiality) than a normal network (first network). Therefore, the ID distribution platform  300  maintains high security, or example, by transmitting. or receiving a hash value or the like, 
     &lt;Exemplary Configuration of Business Operator&#39;s Terminal  200 &gt; 
       FIG.  2    is a diagram illustrating an exemplary configuration of the business operator&#39;s terminal  200 . The business operator&#39;s terminal  200  includes a central processing unit (CPU)  210 , a storage  220 , a memory  230 , and a communication circuit  240 . 
     The storage  220  is an auxiliary storage device that stores programs and data, such as a flash memory, a hard disk drive (HDD), or a solid state drive (SSD). The storage  220  stores a user information registration program  221  and a digital certificate issuance program  222 . 
     The memory  230  is an area in which the program stored in the storage  220  is loaded. Furthermore, the memory  230  may be used as an area in which the program stores data. 
     The CPU  210  is a processor that builds each unit and implements each process by loading the program stored in the storage  220  into the memory  230  and executing the loaded program. 
     The communication circuit  240  is a circuit that communicates with other devices. The communication circuit  240  transmits and receives data to and from the other devices via a network. The communication circuit  240  is, for example, a network interface card (NIC). 
     The CPU  210  constructs a conversion unit and a confirmation request unit by executing the user information registration program  221  and executes user information registration processing. The user information registration processing includes registration processing for acquiring the user information from the user terminal  100  and registering (storing) the user information, and confirmation request processing for requesting the user terminal  100  to confirm registration content. The registration processing is processing that includes conversion processing for acquiring the user information and converting the user information into a management format, and management processing for storing the user information after conversion (converted user information) in an internal memory or the like and managing the user information. The confirmation request processing is processing for transmitting, to the user terminal  100 , a registration content confirmation request including a hash value obtained by hashing the converted user information using a hash function, the hash function, and conversion content including the content converted in the conversion processing. 
     The CPU  210  constructs a certificate issuance unit by executing the digital certificate issuance program  222  and executes digital certificate issuance processing. The digital certificate issuance processing is processing for presenting (disclosing) the managed user information to the other business operator or the user as a digital certificate. The digital certificate issuance processing includes, for example, processing for acquiring permission to disclose the user information from the user  10 . Furthermore, the digital certificate issuance processing is triggered, for example, by a request from the user  10  or a request from the other business operator. Moreover, the business operator&#39;s terminal  200  may execute the confirmation request processing before the user information is disclosed in the digital certificate issuance processing. 
     &lt;Exemplary Configuration of User Terminal  100 &gt; 
       FIG.  3    is a diagram illustrating an exemplary configuration of the user terminal  100 . The user terminal  100  includes a CPU  110 , a storage  120 , a memory  130 , and a communication circuit  140 . 
     The storage  120  is an auxiliary storage device that stores programs and data, such as a flash memory, an HDD, or an SSD. The storage  120  stores a user information registration request program  121 , a registration content confirmation program  122 , a digital certificate issuance request program  123 . 
     The memory  130  is an area in which the program stored in the storage  120  is loaded. Furthermore, the memory  130  may be used as an area in which the program stores data. 
     The CPU  110  is a processor that builds each unit and implements each process by loading the program stored in the storage  120  into the memory  130  and executing the loaded program. 
     The communication circuit  140  is a circuit that communicates with other devices. The communication circuit  140  transmits and receives data to and from other devices via a network. The communication circuit  140  is, for example, an NIC or a wireless communication circuit. 
     The CPU  110  constructs a registration unit by executing the user information registration request program  121  and executes user information registration request processing. The user information registration request processing is processing for requesting the business operator&#39;s terminal  200  to register the user information. 
     The CPU  110  constructs a confirmation unit by executing the registration content confirmation program  122  and executes registration content confirmation processing. The registration content confirmation processing is processing that is executed in response to the registration content confirmation request received from the business operator&#39;s terminal  200 . In the registration content confirmation processing, the user terminal  100  converts the registered user information into the management format according to conversion content, calculates a hash value obtained by hashing the converted user information using a hash function, and compares the received hash value and the calculated hash value. When the compared hash values coincide with each other, the user terminal  100  determines that the user information managed by the business operator&#39;s terminal  200  is correct. The registration content confirmation processing is processing for confirming validity of the managed user information (whether or not correctly managed) in response to the request of the business operator&#39;s terminal  200 . 
     The CPU  110  constructs an issuance request unit by executing the digital certificate issuance request program  123  and executes digital certificate issuance request processing. The digital certificate issuance request processing is processing for requesting the business operator&#39;s terminal  200  to present (disclose) the user information to the other business operator and the user as a digital certificate. For example, the user  10  executes the digital certificate issuance request processing using the user terminal  100  when the user  10  needs to verify personal identification of himself/herself. 
     &lt;User Information Registration Confirmation Processing&gt; 
     The user  10  registers the user information to the business operator  20 . Then, the business operator  20  confirms the user  10  whether or not the user registration is correct. This confirmation is processing that is executed not to distribute wrong user information because there is, for example, a case where the wrong user information is registered, a case where the registered user information is old (for example, attribute of user  10  is changed), or the like. 
     The processing for confirming the user information is executed, for example, when a digital certificate issuance request is issued by the user  10 , when the user  10  registers the user information without via the ID distribution platform  300 , when the business operator  20  tries to issue the user information of the user  10  as a certificate, or the like. In the following, when the user  10  registers the user information without via the ID distribution platform  300  will be described as an example. 
       FIG.  4    is a diagram illustrating an example of a sequence of user information registration confirmation processing. The user  10  uses the user terminal  100  (hereinafter, user terminal  100  may be expressed as subject) and transmits user information registration for registering the user information of the user  10  to the business operator  20  (hereinafter, business operator&#39;s terminal  200  may be expressed as subject) (S 1 ). The user terminal  100  communicates with the business operator&#39;s terminal  200  without via the ID distribution platform  300  and transmits the user information registration including the user information of the user  10 . 
     Upon receiving the user information registration, the business operator&#39;s terminal  200  executes user information registration processing S 100 . The user information registration processing S 100  is processing for converting the user information included in the user information registration into a management format for management by the business operator&#39;s terminal  200  and storing (managing) the user information. 
       FIG.  5    is a diagram illustrating an example of a processing flowchart of the user information registration processing S 100 . The business operator&#39;s terminal  200  waits for receipt of the user information registration (No in S 100 - 1 ), Upon receiving the user information registration (Yes in S 100 - 1 ), the business operator&#39;s terminal  200  converts the user information into the management format (S 100 - 2 ). 
     The business operator&#39;s terminal  200  saves (stores) the converted user information in an internal memory (S 100 - 3 ). The user information is stored in association with, for example, an identifier of the user  10 . 
     The business operator&#39;s terminal  200  hashes the converted user information using a hash function and calculates a hash value (S 100 - 4 ). The hash value is calculated in order to be distributed on the ID distribution platform  300  with high security. 
     The business operator&#39;s terminal  200  transmits a registration content confirmation request including the hash function, the hash value, and conversion content to the user terminal  100  (S 100 - 5 ) and terminates the processing. The conversion content indicates content of the conversion performed in the processing S 100 - 2 . Furthermore, the conversion content may include not only the content of the conversion performed in the processing S 100 - 2  but also content of conversion (all conversions into management format) that is not executed on the user information and may be executed on another piece of user information. 
     Returning to the sequence in  FIG.  4   , the business operator&#39;s terminal  200  converts the user information into the management format (S 100 - 2  in  FIG.  5   ), calculates the hash value of the converted user information (S 100 - 4  in  FIG.  5   ), and transmits the registration content confirmation request including the hash function, the hash value, and the conversion content to the user terminal  100  via the ID distribution platform  300  (S 2 , S 100 - 5  in  FIG.  5   ). 
     Upon receiving the registration content confirmation request, the user terminal  100  executes registration content confirmation processing S 200 . The registration content confirmation processing S 200  is processing for confirming whether or not the registered user information is correct, using the hash value. 
       FIG.  6    is a diagram illustrating an example of a processing flowchart of the registration content confirmation processing S 200 . The user terminal  100  waits for receive a registration content confirmation request (No in S 200 - 1 ). Upon receiving the registration content confirmation request (Yes in S 200 - 1 ), the user terminal  100  converts a format of the registered user information (user information transmitted to the business operator&#39;s terminal  200 ) according to the received conversion content (S 200 - 2 ). 
     Then, the user terminal  100  hashes the user information of which the format has been converted using the received hash function and calculates a hash value (S 200 - 3 ). 
     The user terminal  100  compares the calculated hash value and the received hash value (S 200 - 4 ). When the hash values coincide with each other, the user terminal  100  determines that the user information registered (being registered) is correct (S 200 - 5 ) and terminates the processing. On the other hand, when the hash values do not coincide with each other, the user terminal  100  determines that the user information registered (being registered) is not correct (S 200 - 6 ) and terminates the processing. 
     Returning to the sequence in  FIG.  4   , in the registration content confirmation processing S 200 , the user terminal  100  converts the format of the user information according the conversion content (S 200 - 2  in  FIG.  6   ), calculates the hash value of the converted user information (S 200 - 3  in  FIG.  6   ), compares the calculated hash value with the received hash value (S 200 - 4  in  FIG.  6   ), and determines whether or not the registered user information is correct. 
     User information registration confirmation processing will be described using an example of the user information and the conversion content.  FIG.  7    is a diagram illustrating an example of the user information registration confirmation processing. The user terminal  100  makes user information “Name:_Tanaka” be included in user information registration and transmits the user information registration to the business operator&#39;s terminal  200  (S 10 ). The user information “Name:_Tanaka” is information indicating that data with an attribute “Name” is “_Tanaka”. The attribute is a type of data and, for example, “Name” indicates a name of the user. 
     Upon receiving the user information registration, the business operator&#39;s terminal  200  executes the user information registration processing S 100 . In the user information registration processing S 100 , the business operator&#39;s terminal  200  converts the received user information into a management format according to conversion content I 10  (S 100 - 2  in  FIG.  5   , S 11 ). In the processing S 100 - 2 , the business operator&#39;s terminal  200  deletes “_” from “_Tanaka” according to “delete “_”” in the conversion content I 10  and performs conversion into “Tanaka”. Moreover, the business operator&#39;s terminal  200  changes “T” in “Tanaka” to a lowercase “t” according to “lowercase” in the conversion content I 10  and performs conversion into “tanaka”. The business operator&#39;s terminal  200  performs this conversion (S 11 ) and obtains user information in the management format (user information for management) “Name: tanaka”. 
     As illustrated in  FIG.  7   , in a case where there is a plurality of pieces of conversion content, a list of the conversion content is described as the conversion content I 10 . Furthermore, the conversion content I 10  may be indicated using a logical expression or another language in addition to Japanese as in  FIG.  7   . 
     In the user information registration processing S 100 , the business operator&#39;s terminal  200  hashes the converted user information “Name: tanaka” using a hash function and calculates a hash value (S 100 - 4  in  FIG.  5   , S 12 ). The business operator&#39;s terminal  200  calculates a hash value “abc” obtained by hashing the data “tanaka” of the converted user information “Name: tanaka” using a hash function f 1 . 
     In the user information registration processing S 100 , the business operator&#39;s terminal  200  transmits a registration content confirmation request including the hash function f 1 , the hash value “abc”, and the conversion content I 10  to the user terminal  100  (S 13 , S 100 -S in  FIG.  5   ). 
     Upon receiving the registration content confirmation request, the user terminal  100  executes the registration content confirmation processing S 200 . In the registration content confirmation processing S 200 , the user terminal  100  converts a format of the registered user information according to the received conversion content (S 200 - 2  in  FIG.  6   , S 14 ). In the processing S 200 - 2 , the user terminal  100  deletes “_” from the data “_Tanaka” of the registered user information “Name:_Tanaka” according to “delete “_”” in the conversion content I 10  and performs conversion into “Tanaka”. Moreover, the user terminal  100  changes “T” in “Tanaka” to a lowercase “t” according to “lowercase” in the conversion content I 10  and performs conversion into “tanaka”. The user terminal  100  performs this conversion (S 14 ) and obtains user inform at for management “Name: tanaka”. 
     In the registration content confirmation processing S 200 , the user terminal  100  hashes the converted user information “Name: tanaka” using the hash function and calculates a hash value (S 200 - 3  in  FIG.  6   , S 15 ). The user terminal  100  calculates a hash value “abc” obtained by hashing the data “tanaka” of the converted user information “Name: tanaka” using the received hash function f 1 . 
     The user terminal  100  compares the calculated hash value and the received hash value (S 200 - 4  in  FIG.  6   , S 16 ). The user terminal  100  determines that the calculated hash value “abc” is the same as the received hash value “abc” (Yes in S 200 - 4  in  FIG.  6   ) and determines that the registered user information is correct (S 200 - 5  in  FIG.  6   ). 
     In the first embodiment, the user terminal  100  can perform the format conversion same as that of the business operator&#39;s terminal  200  by receiving the conversion content and can calculate a hash value in a format unique to the business operator. As a result, even in a case where the business operator manages the user information in its unique format, the user can determine whether or not the user information of the user himself/herself is correctly managed. 
     Second Embodiment 
     Next, a second embodiment will be described. In the second embodiment, a business operator&#39;s terminal  200  further adds noise to converted user information at the time in calculation of a hash value. By adding the noise, noise information, in addition to conversion content (how to add noise, noise addition method) is needed in calculation of the hash value, and security is enhanced. 
     &lt;User Information Registration Confirmation Processing&gt; 
     A basic sequence is similar to the sequence in  FIG.  4   . The user terminal  100  transmits user information registration for registering user information of a user  10  in the business operator&#39;s terminal  200  (S 1 ). Upon receiving the user information registration, the business operator&#39;s terminal  200  executes user information registration processing S 101 . 
       FIG.  8    is a diagram illustrating an example of a processing flowchart of the user information registration processing S 101 . The business operator&#39;s terminal  200  waits for receipt of the user information registration (No in S 101 - 1 ). Upon receiving the user information registration (Yes in S 101 - 1 ), the business operator&#39;s terminal  200  converts the user information into the management format (S 101 - 2 ). 
     The business operator&#39;s terminal  200  saves (stores) the converted user information in an internal memory (S 101 - 3 ). 
     The business operator&#39;s terminal  200  adds noise to the converted user information (S 101 - 4 ). The addition of the noise is, for example, to add a predetermined character string to a predetermined position in data of the user information. 
     The business operator&#39;s terminal  200  hashes the user information to which the noise is added (user information with noise) using a hash function and calculates a hash value (S 101 - 5 ). 
     The business operator&#39;s terminal  200  transmits a registration content confirmation request including the hash function, the hash value, the conversion content, and the noise information to the user terminal  100  (S 101 - 6 ) and terminates the processing. The noise information indicates content of the noise that has been added in the processing S 101 - 4 . 
     Returning to the sequence in  FIG.  4   , the business operator&#39;s terminal  200  converts the user information into the management format (S 101 - 2  in  FIG.  8   ), adds noise to the converted user information (S 101 - 4  in  FIG.  8   ), calculates the hash value of the user information to which the noise has been added (S 101 - 5  in  FIG.  8   ), and transmits the registration content confirmation request including the hash function, the hash value, the conversion content, and the noise information to the user terminal  100  via the ID distribution platform  300  (S 2 , S 101 - 6  in  FIG.  8   ). 
     Upon receiving the registration content confirmation request, the user terminal  100  executes registration content confirmation processing S 201 . 
       FIG.  9    is a diagram illustrating an example of a processing flowchart of the registration content confirmation processing S 201 . The user terminal  100  waits for receive a registration content confirmation request (No in S 201 - 1 ). Upon receiving the registration content confirmation request (Yes in S 201 - 1 ), the user terminal  100  converts a format of the registered user information according to the received conversion content (S 201 - 2 ). 
     Then, the user terminal  100  adds noise to the converted user information according to the received noise information (S 201 - 3 ). 
     Then, the user terminal  100  hashes the user information to which the noise has been added using the received hash function and calculates a hash value (S 201 - 4 ). 
     The user terminal  100  compares the calculated hash value and the received hash value (S 201 - 5 ). When the hash values coincide with each other, the user terminal  100  determines that the registered user information is correct (S 201 - 6 ) and terminates the processing. On the other hand. When the hash values do not coincide with each other, the user terminal  100  determines that the registered user information is not correct (S 201 - 7 ) and terminates the processing. 
     Returning to the sequence in  FIG.  4   , in the registration content confirmation processing S 201 , the user terminal  100  converts the format of the user information according to the conversion content (S 201 - 2  in  FIG.  9   ), adds the noise to the converted user information according to the noise information (S 201 - 3  in  FIG.  9   ), calculates the hash value of the user information to which the noise has been added (S 201 - 4  in  FIG.  9   ), compares the calculated hash value with the received hash value (S 201 - 5  in  FIG.  9   ), and determines whether or not the registered user information is correct. 
     User information registration confirmation processing will be described using an example of noise information.  FIG.  10    is a diagram illustrating an example of the user information registration confirmation processing according to the second embodiment. The user terminal  100  makes user information “Name:_Tanaka” be included in user information registration and transmits the user information registration to the business operator&#39;s terminal  200  (S 20 ). 
     Upon receiving the user information registration, the business operator&#39;s terminal  200  executes the user information registration processing S 101 . In the user information registration processing S 101 , the business operator&#39;s terminal  200  converts the received user information into a management format according to conversion content I 10  (S 101 - 2  in  FIG.  8   , S 21 ). In the processing S 101 - 2 , the business operator&#39;s terminal  200  deletes “_” from “_Tanaka” according to “delete “_”” in the conversion content I 10  and performs conversion into “Tanaka”. Moreover, the business operator&#39;s terminal  200  changes “T” in “Tanaka” to a lowercase “t” according to “lowercase” in the conversion content I 10  and performs conversion into “tanaka”. The business operator&#39;s terminal  200  performs this conversion (S 21 ) and obtains user information for management “Name: tanaka”. 
     In the user information registration processing S 101 , the business operator&#39;s terminal  200  adds noise to the user information for management according noise information I 11  (S 101 - 4  in  FIG.  8   ). The business operator&#39;s terminal  200  obtains “Name: txyzanaka” obtained by adding “xyz” after the second character of the user information for management “Name: tanaka” according to “add “xyz” after the first character” in the noise information I 11 . 
     In the user information registration processing S 101 , the business operator&#39;s terminal  200  hashes the user information to which the noise has been added using the hash function and calculates a hash value (S 101 - 5  in  FIG.  8   , S 23 ) The business operator&#39;s terminal  200  calculates, using a hash function f 1 , a hash value “def” obtained by hashing data “txyzanaka” of the user information “Name: txywzanaka” to which the noise has been added. 
     In the user information registration processing S 101 , the business operator&#39;s terminal  200  transmits a registration content confirmation request including the hash function f 1 , the hash value “def”, the conversion content I 10 , and the noise information I 11  to the user terminal  100  (S 24 , S 101 - 6  in  FIG.  8   ). 
     Upon receiving the registration content confirmation request, the user terminal  100  executes the registration content confirmation processing S 201 . In the registration content confirmation processing S 201 , the user terminal  100  converts a format of the registered user information according to the received conversion content (S 201 - 2  in  FIG.  9   , S 25 ). In the processing S 201 - 2 , the user terminal  100  deletes “_” from the data “_Tanaka” of the registered user information “Name:_Tanaka” according to “delete “_”” in the conversion content I 10  and performs conversion into “Tanaka”. Moreover, the user terminal  100  changes “T” in “Tanaka” to a lowercase “t” according to “lowercase” in the conversion content I 10  and performs conversion into “tanaka”. The user terminal  100  performs this conversion (S 25 ) and obtains user information for management “Name: tanaka”. 
     In the registration content confirmation processing S 201 , the user terminal  100  adds noise to the user information for management according to the received noise information I 11  (S 201 - 3  in  FIG.  9   , S 26 ). The user terminal  100  obtains “Name: txyzanaka” obtained by adding “xyz” after the second character of the user information for management “Name: tanaka” according to “add “xyz” after the first character” in the noise information I 11 . 
     In the registration content confirmation processing S 201 , the user terminal  100  hashes the user information to which the noise has been added using the hash function and calculates a hash value (S 201 - 4  in  FIG.  9   , S 27 ). The user terminal  100  calculates, using the received hash function f 1 , a hash value “def” obtained by hashing data “txyzanaka” of the user information “Name: txyzanaka” to which the noise has been added. 
     The user terminal  100  compares the calculated hash value and the received hash value (S 201 - 5  in  FIG.  9   , S 28 ). The user terminal  100  determines that the calculated hash value “def” is the same as the received hash value “def” (Yes in S 201 - 5  in  FIG.  9   ) and determines that the registered user information is correct (S 201 - 6  in  FIG.  9   ). 
     In the second embodiment, by using the user information to which the noise has been added to calculate the hash value, the security is enhanced. 
     Other Embodiments 
     Other embodiments will be described. User information may be described in Japanese. For example, a user terminal  100  transmits user information registration including user information “Name: tanaka (in Katakana)” and a business operator&#39;s terminal  200  converts Katakana into Hiragana as in conversion content and saves (manages) user information for management “Name: tanaka (in Hiragana)”. Even in this case, the user terminal  100  can confirm validity of the user information by receiving the conversion content from the business operator&#39;s terminal  200 . Furthermore, regarding noise addition, processing similar to the second embodiment can be executed. 
     Furthermore, conversion other than conversion content described above may be performed.  FIG.  11    is a diagram illustrating an example of format conversion. “(1) Deletion of blanks at the beginning and end” is conversion to delete blanks in a case where the blanks (space) exist at the beginning and the end. “(2) Deletion of consecutive blanks” is conversion to delete consecutive blanks in a case where the consecutive blanks exist. “(3) Conversion of uppercase/lowercase” is conversion to change an uppercase to a lowercase or a lowercase to an uppercase. “(4) Conversion of full-width/half-width” is conversion to change full-width to half-width or half-width to full-width. “(5) Conversion of Hiragana/Katakana” is conversion to change Hiragana to Katakana or Katakana to Hiragana. “(6) Conversion into date format (yyyy/mm/dd)” is conversion to change data into a yyyy/mm/dd format. The expression yyyy indicates the Christian Era year, the expression mm indicates a month (for example, January is expressed as 01), and the expression dd indicates a date (for example, the first day is expressed as 01). “(7) Conversion into phone number format (000-000-0000)” is conversion to change data into a 000-000-0000 (0 is any numerical number) format. The number of any numerical numbers in the phone number format may be different for a mobile phone or a landline. 
     The lower table in  FIG.  11    is a diagram illustrating an example of an attribute and conversion. An attribute “Name” indicates a name, and conversions (1), (2), and (3) are performed. For example, “Tanaka” is converted into “tanaka”. An attribute “Birthday” indicates a birthday. An attribute “Address” indicates an address. An attribute “Telephone” indicates a telephone number. An attribute “Occupation” indicates an occupation. An attribute “Email” indicates an email address. In data of each attribute, as illustrated in the conversion examples, the conversion described in the conversion content is performed. Note that the business operator&#39;s terminal  200  may transmit an information content confirmation request including the conversion example as illustrated in  FIG.  11    in addition to the conversion content. 
     Furthermore, noise may be added by a method other than the noise addition described above.  FIG.  12    is a diagram illustrating an example of noise information. “Tokenization” is a method for adding a character string (value) to a specific position and is a method indicated in the embodiments described above. 
     “Masking” is a method for replacing a specific position with a specific character. For example, in a case where the first and second characters are replaced with “*”, “tanaka” is converted into “**naka”. 
     “Exchange” is a method for exchanging characters at specific positions. For example, in a case where the first and second characters are exchanged to each other, “tanaka” is converted into “atnaka”. Note that the business operator&#39;s terminal  200  may transmit the information content confirmation request including an application example as illustrated in  FIG.  12    in addition to the noise information. 
     All examples and conditional language provided herein are intended for the pedagogical purposes of aiding the reader in understanding the invention and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although one or more embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.