Blockchain update system, server device, client device, blockchain update method, and program

摘要

To safely and efficiently update a block chain.SOLUTION: A server device 1 divides a search space into a form in which parallel computation can be performed, and converts the search spaces after division into a form in which request computation can be performed. A client device 2 requests transaction from the server device 1. The server device 1 transmits any one of the search spaces after the conversion to the client device 2. The client device 2 computes a unidirectional function by using the search space after the conversion received from the server device 1, and transmits a result of request computation and information necessary for checking the transaction to the server device 1. The server device 1 receives the result of request computation and information necessary for checking the transaction from the client device 2, verifies whether or not a result of computation of the unidirectional function obtained by inversely converting the result of request computation and the information necessary for checking the transaction are correct, and updates a block chain by using a result of computation satisfying a predetermined condition.SELECTED DRAWING: Figure 4