CALCULATION APPARATUS, CALCULATION METHODS, AND PROGRAMS

1 . A computing device serving as a node of a blockchain comprising processing circuitry configured to:

execute processing for obtaining consensus using a consensus algorithm of the blockchain; and

store, in a block of the blockchain, a one-way function value of at least one of secret information obtained by securely distributing information based on original information and a secure computation result obtained by performing secure computation on the secret information in a case in which the consensus is obtained using the consensus algorithm of the blockchain.

2 . The computing device according to claim 1 , wherein the processing circuitry is further configured to perform the secure computation on the secret information in accordance with a processing request from a smart contract function using the blockchain to obtain the secure computation result.

3 . The computing device according to claim 2 , wherein

a request other than the processing request from the smart contract function is blocked.

4 . The computing device according to claim 1 , wherein

a one-way function value of at least one of other secret information obtained by securely distributing information based on the original information and another secure computation result obtained by performing secure computation on the other secret information is stored in a block of another blockchain by another computing device serving as a node for which consensus is obtained using a consensus algorithm of the other blockchain other than the blockchain.

5 . The computing device according to claim 1 , wherein

a one-way function value of at least one of other secret information obtained by securely distributing information based on the original information and another secure computation result obtained by performing secure computation on the other secret information is stored in a block of the blockchain by another computing device serving as another node for which consensus is obtained using the consensus algorithm of the blockchain.

6 . The computing device according to claim 5 , wherein

the consensus for the computing device and the other computing device is obtained in parallel using the consensus algorithm of the blockchain, and

the processing circuitry stores at least one one-way function value of the secret information and the secure computation result in the block of the blockchain in which at least one one-way function value of the other secret information and the other secure computation result is stored by the other computing device.

7 . The computing device according to claim 5 , wherein

after the consensus for the other computing devices is obtained using the consensus algorithm of the blockchain, the consensus for the computing devices is obtained using the consensus algorithm of the blockchain, and

after the consensus for the computing device is obtained using the consensus algorithm of the blockchain, the computing device performs the secure computation on the secret information to obtain the secure computation result, the other computing device performs the secure computation on the other secret information to obtain the other secure computation result, and the one-way function value of the secure computation result and the other secure computation result are stored in the block of the blockchain by the computing device.

8 . The computing device according to claim 5 , wherein

after the consensus for the other computing device is obtained using the consensus algorithm of the blockchain, the one-way function value of the other secret information is stored in the block of the blockchain by the other computing device,

after the one-way function value of the other secret information is stored in the block of the blockchain by the other computing device, the consensus for the computing device is obtained using the consensus algorithm of the blockchain, and

after the consensus for the computer device is obtained using the consensus algorithm of the blockchain, the computer device performs the secure computation on the secret information to obtain the secure computation result, the other computer device performs the secure computation on the other secret information to obtain the other secure computation result, and the computing device stores the one-way function value of the secret information, the one-way function value of the secret computing result, and the other secret computing result in the block of the blockchain.

9 . The computing device according to claim 1 , wherein

the original information is information identifying an aggregated model in federated learning,

the information based on the original information is information identifying a worker model obtained by updating the aggregated model by machine learning, and

the secure computation is computing configured to obtain the secure computation result, which is secret information of the information identifying the aggregated model obtained by aggregating a plurality of worker models, using the secret information, without obtaining the worker model.

10 . A computing method performed by a computing device serving as a node of a blockchain, comprising:

executing processing for obtaining consensus using a consensus algorithm of the blockchain; and

storing, in a block of the blockchain, a one-way function value of at least one of secret information obtained by securely distributing information based on original information and a secure computation result obtained by performing secure computation on the secret information in a case in which the consensus is obtained using the consensus algorithm of the blockchain.

11 . A non-transitory computer-readable recording medium storing a program causing a computer to function as the computing device according to claim 1 .