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 block generation method is performed by a block generation device that generates a block in a blockchain and includes: obtaining transaction data including a power-saving request to save power required for a generation process related to generation of the block by the block generation device; and executing the generation process by consuming an amount of power that meets the power-saving request.

Abstract: A control method of a fund management system including a plurality of servers that hold a distributed ledger, and executed by one of the plurality of servers, includes: receiving transaction data, the transaction data pertaining to payment processing for payment of a token from one or more applicants of crowdfunding to a management account, and storing the transaction data that is received in the distributed ledger held in each of the plurality of servers; determining, using a smart contract, whether or not a target condition of the crowdfunding is met; and outputting information indicating a result of the determining.

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 of an analysis device includes analyzing a binary code of each of a plurality of smart contracts stored in a first distributed ledger; obtaining, by using a result of the analyzing, items of commonization information expressing, in a common format, items of information provided by the plurality of smart contracts; and generating transaction data that includes the items of commonization information obtained and performing control of storing the transaction data generated into a second distributed ledger.

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: An information processing method to be performed by an information processing device using a processor includes: obtaining value information owned by a user and indicating a contribution to the natural environment as an environmental value; determining, according to the environmental value indicated in the value information obtained, a function to be provided to the user who uses a virtual space generated by a computer; and providing the determined function to the user.

Abstract: A method includes: recording provision record information in which provider identification information which identifies a data provider, data identification information which identifies each of one or more items of provided data generated by a home appliance, and value reference information which serves as a reference for calculating a data value of each of the one or more items of provided data are associated with one another; and when the one or more items of provided data include used data that is data used by a data user, determining an incentive for the data provider of the used data based on the provision record information. The value reference information includes an index value determined by each of a plurality of value indexes.

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.

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 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 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 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: An information processing method that, in a system including a plurality of information processing devices each holding a blockchain, is executed by one information processing device out of the plurality of information processing devices, includes: generating a first block including one or more items of transaction data, and connecting the first block to the blockchain; generating transaction data indicating payment of a reward for generating the first block, when at least T blocks are connected downstream of the first block in the blockchain where T is an integer greater than or equal to 1; and generating a second block including the transaction data generated, and connecting the second block to the blockchain.

Abstract: A control method in which each of an Internet of things (IoT) device and a user who uses the IoT device has a digital account includes: obtaining first transaction data for allowing the user who used the IoT device to transfer a first amount corresponding to a usage amount of the IoT device; specifying, from the first transaction data obtained, the digital account of the IoT device that is associated with an identifier uniquely assigned to hardware of the IoT device; and transferring the usage amount of the IoT device to the digital account of the IoT device by deducting the first amount from the digital account of the user and adding the first amount to the digital account of the IoT device based on the first transaction data obtained.

Abstract: A method includes: acquiring transaction data that includes value information regarding a value to be transferred from a second user to a first user; executing a first smart contract recorded in a first blockchain by recording the transaction data in the first blockchain; and executing a second smart contract recorded in a second blockchain different from the first blockchain based on the first smart contract. The second smart contract is a smart contract for transferring at least a portion of the value to be transferred from the second user to the first user, from a first account held by the first user to a third account held by a third user.

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: 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: 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.