Abstract: A control method includes: receiving first information pertaining to a first contract from a first terminal used by a first user who is one of two parties who have agreed to the first contract; when consent of a party aside from the two parties is required to validate the first contract, identifying a second user as the party aside from the two parties with reference to a ledger storing information pertaining to a past contract, and transmitting the first information to a second terminal operated by the second user; obtaining second information in which a confirmation result indicating whether the second user consents to the first contract and a digital signature of the second user are added to the first information; and confirming the second information, and when the confirmation result indicates consent, setting the first contract as a valid contract and storing the second information in the ledger.

Abstract: A fault monitoring method is executed by a monitoring device in a fault monitoring system that includes a terminal used by a user, an appliance to be operated by the user, the monitoring device, and a plurality of authentication servers each including a distributed ledger, and includes: obtaining event information stored in the plurality of authentication servers and indicating an event generated in response to a request that includes a processing instruction for the user operating the appliance; obtaining state information indicating whether the appliance is faulty, from the appliance; generating first transaction data including the state information obtained and transmitting the first transaction data to the plurality of authentication servers; and transmitting the processing instruction included in the event information to the appliance, when the appliance is determined to be not faulty from the state information.

Abstract: A data management method performed by a first authentication server included in a plurality of authentication servers each having a distributed ledger in a data management system including a device and the plurality of authentication servers includes: obtaining first transaction data generated by the device and including device data obtained or generated by the device; and generating a block including the first transaction data and recording the generated block in the distributed ledger, when the device data included in the first transaction data is first data indicated in an information type list which is a data list indicating data that is subject to recording in the distributed ledger and related to a predetermined contract.

Abstract: A method includes: associating one or more data managers with mutually different models of a plurality of home appliances the one or more data managers managing data items generated by the plurality of home appliances; recording provision record information in which data identification information and manager identification information are associated with each other, the data identification information identifying each of one or more data items generated by the plurality of home appliances, the manager identification information identifying each of the one or more data managers; and determining, when the one or more data items include a used data item used by a data user, an amount to be transferred to a data manager that manages the used data item, based on the provision record information.

Abstract: A method for controlling one of voting servers in an electronic voting system is provided. The method includes receiving, from a terminal, transaction data including voting data, and determining, by a processor, a block to include the transaction data from among multiple blocks. The method further includes generating, using the processor, the block including the transaction data, and connecting the block to a blockchain, the blockchain being stored in a memory.

Abstract: Provided is a control method which includes: obtaining battery information which is information regarding a battery; calculating a present residual value of the battery based on the battery information obtained; calculating a first residual value using a first model which has been trained, the first residual value being a residual value of the battery in a case where a user uses the battery with a tendency identical to a tendency of a plurality of other users; and issuing a token to the user according to an evaluation value calculated based on the present residual value and the first residual value calculated.

Abstract: A control method according to the present disclosure includes: receiving, from a terminal operated by a first user who is one of parties that have concluded a first contract, first transaction data that includes a first smart contract corresponding to the first contract and a first electronic signature associated with the first user; executing a consensus algorithm with a plurality of other servers; and recording a block including the first transaction data in a distributed ledger. The first smart contract includes (i) content of the first contract which is a main contract, (ii) a variable that is provisional and used for identifying a second smart contract corresponding to a second contract which is to be newly concluded as a sub contract of the first contract, and (iii) a condition for creation of the second smart contract.

Abstract: A control method according to the present disclosure is executed by a first server of servers in a system including one or more IoT devices and the servers. The method includes: obtaining first transaction data including operation notification information and time information from each of the IoT devices, the operation notification information including identification information on the IoT device and a notification indicating that the IoT device is operating, the time information indicating a time when the IoT device has obtained the operation notification information; transferring the obtained first transaction data to second servers different from the first server; executing a first consensus algorithm together with the second servers; and recording a block containing the first transaction data in a distributed ledger of the first server, when the authenticity of the first transaction data is verified by the first consensus algorithm.

Abstract: A method for controlling one of a plurality of voting servers in an electronic voting system is provided. The method includes receiving, from a terminal, transaction data including voting data, and generating, using a processor, a block including the transaction data and dummy transaction data. The dummy transaction data including dummy voting data that is not associated with the voting data. The method further connects the generated block to a blockchain, the blockchain being stored in a memory.

Abstract: The present disclosure provides a management method for software versions to improve transaction safety of software. In the management method, among management apparatuses, a first token management apparatus obtains request information indicating a requested version requested by a user, and first transaction data indicating that the user provides predetermined number of tokens to a software developer who has developed the requested version is stored in distributed ledgers through execution of a consensus algorithm by the management apparatuses.

Abstract: A vehicle in a driving management system including one or more authentication servers and one or more vehicles capable of switching between a manual driving mode and an automatic driving mode is provided. The vehicle includes a communication unit that communicate with at least one authentication server of the one or more authentication servers, and a detecting unit that detects switching between the manual driving mode where manual driving is performed, and an automatic driving mode where automatic driving is performed, based on a message issued by at least one of the plurality of electronic control processors. The vehicle also includes a generating unit that generates transaction data including information indicating the detected switching, and an identifier indicating the vehicle, and transmits, to the at least one authentication server, the transaction data.

Abstract: In a data management method, a plurality of servers store, in a distributed ledger, at least one instance of transaction data each including record information; the record information includes a record of at least one data set; and each data set includes at least one instance of data, among a plurality of instances of data generated by a plurality of devices, satisfying a condition corresponding to the data set. The data management method includes a first terminal owned by a first user of a target data set, or a second terminal owned by a second user of the target data set, performing the following: obtaining the record of at least one similar data set similar to the target data set from the record information; and determining a value of the target data set based on the record obtained.

Abstract: Provided is a control method which includes: obtaining battery information which is information regarding a battery; calculating a present residual value of the battery based on the battery information obtained; calculating a first residual value using a first model which has been trained, the first residual value being a residual value of the battery in a case where a user uses the battery with a tendency identical to a tendency of a plurality of other users; and issuing a token to the user according to an evaluation value calculated based on the present residual value and the first residual value calculated.

Abstract: A control method according to the present disclosure includes: receiving, from a terminal operated by a first user who is one of parties that have concluded a first contract, first transaction data that includes a first smart contract corresponding to the first contract and a first electronic signature associated with the first user; executing a consensus algorithm with a plurality of other servers; and recording a block including the first transaction data in a distributed ledger. The first smart contract includes (i) content of the first contract which is a main contract, (ii) a variable that is provisional and used for identifying a second smart contract corresponding to a second contract which is to be newly concluded as a sub contract of the first contract, and (iii) a condition for creation of the second smart contract.

Abstract: A control method that is performed by a first device included in a plurality of devices includes: receiving, from a terminal being used by a second user, first transaction data indicating that value information is to be transferred from a first user to the second user; and storing the received first transaction data into a distributed ledger.

Abstract: A method includes: transmitting, to a second device used by a second user, identification information of a smart contract including a process of providing content according to a provision condition under which a first user allows to provide the content, through short-range wireless communication; receiving transaction data including identification information of the second device and instruction information for instructing to execute the smart contract, through short-range wireless communication; and storing the transaction data received in a distributed ledger and executing the smart contract, to change an owner of the content from the first user to the second user.

Abstract: A control method to be executed by a first device includes: receiving identification information identifying a second device from the second device by near-field communication; determining an evaluation value indicating appropriateness of the processing executed by the second device, with reference to a storage device that stores history information indicating processing executed by the second device; and restricting the near-field communication with the second device, based on the evaluation value determined.

Abstract: A control method according to the present disclosure is a method for controlling a first terminal carried by a first user and capable of communicating with a server via a network and includes: establishing short-range wireless communication by the first terminal with a second terminal carried by a second user; requesting the second terminal by the first terminal via the short-range wireless communication to provide item information, which is information related to at least one item included in one or more items worn by the second user, or requesting the server by the first terminal via the network to provide the item information, using identification information of at least one item that has been obtained upon the establishment of the short-range wireless communication; obtaining the item information by the first terminal; and transmitting, to the server, item positive-obtainment information indicating that the item information has been obtained.

Abstract: A method controls one of a plurality of voting servers in an electronic voting system. The method includes receiving, from one or more terminals, one or more voting data including a first identifier (ID) associated with a vote cast by a voter and voting information indicating the vote. The method also includes generating a block including the one or more voting data when the one or more voting data satisfies a predetermined criterion of anonymization, and connecting the block to a blockchain stored in a memory.

Abstract: A control method according to the present disclosure is executed by a first server of servers in a system including one or more IoT devices and the servers. The method includes: obtaining first transaction data including malfunction information indicating that one of the IoT devices is malfunctioning, and time information indicating a time when the IoT device has obtained the malfunction information; transferring the obtained first transaction data to second servers different from the first server; executing, together with the second servers, a first consensus algorithm for an agreement on an authenticity of the first transaction data; and recording a block containing the first transaction data in a distributed ledger of the first server, when the authenticity of the first transaction data is verified by the first consensus algorithm.