Abstract: A storage unit stores transaction data to be recorded on a blockchain. When receiving identification information identifying a processing system for processing the transaction data among processing systems, a processing unit calculates a function value using a parameter corresponding to the received identification information and a function. The processing unit notifies a determination unit, which determines the processing system for processing the transaction data from among the processing systems, of the transaction data and signature data generated from the function value.

Abstract: A control method implemented by a first node in a blockchain network, the blockchain network including the first node that stores logic of first processing and a second node that does not store the logic of the first processing, the control method including: executing the first processing on the basis of the logic of the first processing; and when the first processing is executed, recording, in a blockchain managed by the blockchain network, a block that includes information that indicates that the first processing has been executed.

Abstract: A transmission control method of a transaction stored in a block included in a blockchain in which a computer executes processing including, when receiving a reference request of the transaction, transmitting a verification request of the transaction to a node included in a blockchain network, and when receiving a verification result by the node, generating a verification block that stores the verification result, connecting the generated verification block to the blockchain, and controlling whether or not to transmit the transaction to a request source of the reference request on the basis of the verification result, and as a result, the transmission control method suppresses a processing load of the node included in the blockchain network.

Abstract: A transaction management device includes: a memory; and a processor coupled to the memory. The processor is configured to register, into a database, with respect to a first blockchain that stores a plurality of transactions with which first information and second information are associated, a plurality of multiple pieces of the second information in the plurality of transactions in units of groups based on the first information; and register, into a second blockchain, hash values obtained by hashing the plurality of pieces of second information in the units cf groups.

Abstract: A method includes: obtaining a policy for a blockchain, the policy including plural logics configured to receive a respective input value and output a respective output value, any of the plural logics being configured to receive an output value from another logic; obtaining, for each logic in the policy, an input value and an output value from the blockchain; transmitting to a first node a first request including a first logic and the input and output values for the first logic, thereby causing the first node to verify the first logic using the input and output values for the first logic; and transmitting to a second node other than the first node a second request including a second logic and the input and output values for the second logic, thereby causing the second node to verify the second logic using the input and output values for the second logic.