The present invention prevents falsification of ABI information and makes it possible for the users to safely read data on a blockchain. A registration terminal 1 includes an extraction unit 142 that extracts from a smart contract, ABI information used to access the smart contract and a transaction issuing unit 13 that issues a transaction including bytecode generated by compiling the smart contract and the ABI information, and an approval terminal 2 includes a verification unit 152 that verifies whether it is possible to access the bytecode included in the transaction by using the ABI information included in the transaction and a block generation unit 154 that, if it is possible to access the bytecode, generates a block including the transaction and makes the block and the ABI information reflected on a distributed ledger 11 of each terminal in the blockchain system.