NODE GROUP MANAGING DEVICE AND COMPUTING DEVICE FOR CONFIGURING GROUP KEY-BASED DUAL SIGNATURE TRANSACTION STRUCTURE IN BLOCKCHAIN NETWORK

A node group managing device according to an embodiment comprises: a communication interface which communicates with a blockchain network and manages a first group to which a part belongs of nodes constituting the blockchain network in which a distributed database is shared, wherein every node joining the blockchain network holds a private key and a public key; at least one memory which stores information related to the nodes in the first group and an instruction as to a processor operation, wherein the information related to the nodes in the first group contains the public key of each of the nodes in the first group; and at least one processor which is connected to the at least one memory to operate according to the instruction and performs an operation of generating a group private key that, when a node in the first group creates a transaction, together with a signature for the private key to be put to the transaction, causes an additional signature to be put to the transaction on the basis of the informati