A node device configuring a peer-to-peer network includes: a network interface; and a blockchain management part configured to receive, through the network interface, an information registration request transaction that includes embedded Subscriber Identity Module, SIM, information including SIM identification information, an electronic signature put on the embedded SIM information by using a private key of an information registrant, and a public key paired with the private key, and accumulate the received information registration request transaction into a blockchain based on a consensus building algorithm executed in cooperation with another node device configuring the peer-to-peer network.