Abstract: A control method includes: obtaining first transaction data that includes a first variable indicating first information on a first contract made between a first user and a second user, and a second variable set to a predetermined value indicating second information is undetermined; storing the first transaction data into the distributed ledger; executing storing processing of reading out the second variable, and storing it into a rewritable storage in a server; obtaining second transaction data that includes a third variable indicating third information on a second contract made between the first user and a third user, and a change command for changing the second variable, based on the third variable; storing the second transaction data into the distributed ledger; and executing change processing of changing, according to the change command, the second variable from the predetermined value, after the second transaction data is stored into the distributed ledger.

Abstract: A control method includes: obtaining first transaction data that includes first information on a first contract made between a first user and a second user; storing the first transaction data obtained into the distributed ledger; obtaining second transaction data that includes second information on a second contract made between the first user and a third user; storing the second transaction data obtained into the distributed ledger; obtaining third transaction data using the first information and the second information, when one of the first transaction data and the second transaction data is associated with a remaining one of the first transaction data and the second transaction data, the third transaction data including third information on a third contract made between the second user and the third user; and storing the third transaction data obtained into the distributed ledger.

Abstract: A control method is executed by one device among devices included in a management system. Each of the devices includes a distributed ledger and stores: a parent smart contract including an automatic generation function of automatically generating a new smart contract; and a management function of selecting and managing one of child smart contracts generated by the devices. The control method includes: generating a first child smart contract; transmitting first transaction data including the generated first child smart contract to a different device and storing the first transaction data into the distributed ledger of the one device; receiving second transaction data including a second child smart contract generated by the different device and storing the second transaction data into the distributed ledger of the one device; and managing one child smart contract in association with the parent smart contract through execution of the management function.

Abstract: A control method includes: storing, into a distributed ledger, first transaction data that includes a first variable indicating an authorizer, the first variable being set to a predetermined value indicating that the authorizer is undetermined; executing storing processing of storing the predetermined value into a rewritable storage; obtaining second transaction data that includes a change command for changing the first variable to identification information of a third user; storing the second transaction data into the distributed ledger; executing change processing of changing, according to the change command, the first variable stored in the storage; obtaining third transaction data that includes a fulfillment command for executing fulfillment processing of fulfilling a first contract; storing the third transaction data into the distributed ledger; and executing the fulfillment processing according to the fulfillment command when the first variable stored in the storage is determined to be other than the pr

Abstract: A control method is executed by a first server among a plurality of servers in a system including the plurality of servers and a generating device that generates record information about usage records for users belonging to one group when a service provided by a business operator is used on a group basis. The method includes: obtaining, from the generating device, first record information about a first usage record of a service by a first user belonging to the one group; determining whether the first record information obtained is permitted under a rule based on contract content, stored in the first server, of a contract entered into by the first user and the business operator; and forwarding first transaction data including a determination result to a plurality of second servers and storing a first block including the first transaction data in a distributed ledger managed by the first server.

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: First information including first contract information indicating contract content of a first contract and a provisional contract flag indicating that the first contract information is a provisional contract is received from a first terminal used by a first user who is one of two parties that have agreed to the first contract, and is stored into a ledger. The first contract information obtained from the ledger is transmitted to a second terminal used by an auditor who inspects the first contract information. A check result indicating approval or disapproval of the first contract information by the auditor is received from the second terminal. When the check result indicates approval of the first contract information, second information including the first contract information and a definitive contract flag indicating that the first contract information has been adopted as a definitive contract is obtained and stored into the ledger.

Abstract: The present disclosure provides a management method for software versions which prevents falsification of information under management. In the management method, a first management apparatus among management apparatuses receives transaction data from an apparatus connected through a network to the first management apparatus, the transaction data including first information on a first version of software, second information on a second version of the software subjected to version upgrade from the first version by a software developer, identification information of the software developer, and an electronic signature. The first management apparatus validates legitimacy of the transaction data using the electronic signature included in the transaction data received. When the transaction data is legitimate, the management apparatuses store the transaction data in distributed ledgers.

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 control method includes: generating first transaction data including latest information acquired by a first time, and transmitting the first transaction data to a first server; checking a block recorded in a distributed ledger of the first server at a second time that happens one or more times after the first time to determine, when second transaction data next to the first transaction data is generated at the second time, whether a first block included when the first transaction data is recorded into the distributed ledger is different from a second block included when the second transaction data is recorded into the distributed ledger; and when it is determined that the first block is different from the second block, generating, at the second time or thereafter, the second transaction data that includes latest information acquired after the first time, and transmitting the second transaction data to the first server.

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 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 includes obtaining, from a terminal, reservation information including use start date and time of an electric-powered vehicle that a first user hopes to use; obtaining an amount of remaining battery of the electric-powered vehicle; determining, based on the amount of remaining battery, whether an amount of remaining battery of the electric-powered vehicle is no less than a predetermined value at the use start date and time; and transmitting, to the terminal, notification information indicating a result of the determining. For example, the determination includes calculating, based on a predetermined charging characteristic unique to a battery of the electric-powered vehicle, an amount of remaining battery to be held by the electric-powered vehicle at the use start date and time upon the electric-powered vehicle being charged at a charging station; and determining whether the amount of remaining battery of the electric-powered vehicle is no less than the predetermined value.

Abstract: A control method includes obtaining, from a first terminal of a first user, reservation information including a use start date and time of an electric-powered vehicle that the first user hopes to use at a future time and that is being used by a second user; obtaining an amount of remaining battery of the electric-powered vehicle; calculating charge start date and time based on the amount of remaining battery obtained, the charge start date and time being a date and time at which the electric-powered vehicle should start being charged so that an amount of remaining battery of the electric-powered vehicle becomes no less than a predetermined value at the use start date and time included in the reservation information obtained; and transmitting notification information including the charge start date and time calculated to the electric-powered vehicle.

Abstract: A control method is executed by one server out of a plurality of servers, each managing one of a plurality of distributed ledgers. The control method includes receiving first transaction data from a measured-value server over a network, the measured-value server providing, for each of one or more parameters for determining a price for a variable-price service, a measured value that corresponds to the parameter, and the first transaction data including the one or more parameters, the measured value, and a location and a time where and when the measured value is obtained; and transferring the received first transaction data to other servers different from the one server out of the plurality of servers and storing a first block including the first transaction data into a first distributed ledger managed by the one server.

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 control method includes: receiving application information including a scheduled date and time of a transaction, from a terminal; calculating, with reference to a distributed ledger, a fee based on a transaction by a first user recorded in the distributed ledger before the scheduled date and time included in the application information; transmitting fee information including the fee, to the terminal; receiving first transaction data including a first token quantity for the transaction, transferring the first transaction data to a plurality of other servers different from a server from among a plurality of servers, and storing a first block including the first transaction data in the distributed ledger; and receiving second transaction data including a second token quantity for the fee, transferring the second transaction data to the plurality of other servers, and storing a second block including the second transaction data in the distributed ledger.

Abstract: A control method includes: receiving first transaction data related to a sign-up for crowdfunding from at least one participant and storing the first transaction data received into a distributed ledger which is included in each of the servers and stores beforehand reward information specifying a reward amount that is to be offered for each of the at least one participant and that has a tendency to decrease with a later timing of the sign-up of the at least one participant; determining, by reference to the reward information, the reward amount for each of the at least one participant based on a timing at which the first transaction data is received; and storing, into the distributed ledger, second transaction data indicating that each of the at least one participant is offered the reward amount determined in the determining, if it is determined that a goal condition of the crowdfunding is satisfied.

Abstract: A control method includes: receiving first transaction data related to a sign-up for service and storing the first transaction data received into the distributed ledger included in each of the plurality of servers, the service offering, if a goal condition predetermined for the service is satisfied, a token to a participant that is a user who signs up for the service; storing, into the distributed ledger, second transaction data indicating that the user is offered the token predetermined for the service, if it is determined that the goal condition is satisfied; and storing, into the distributed ledger, third transaction data indicating that the user is offered a deposit that is a temporary token predetermined for the service, at a predetermined timing included in a period from the storing of the first transaction data into the distributed ledger until when determination of whether the goal condition is satisfied is performed.

Abstract: A control method that, in an information management system including a plurality of servers each having a distributed ledger, is executed by a server from among the plurality of servers, includes: receiving first transaction data that includes identification information and permission or non-permission information, the identification information being associated with user information that is managed in the information management system and relates to a first user, the permission or non-permission information indicating whether provision of the user information to a second user is permitted; and storing the first transaction data received, in the distributed ledger in each of the plurality of servers.