Control method, server, and recording medium

A control method used by a proxy server that acts as an intermediary between a peer-to-peer (P2P) system and a management system, the management system including servers each holding a distributed ledger, the control method comprising:

• receiving first peer information and a signature, the first peer information being information about a first peer and being used for connecting the first peer among peers in the P2P system to another peer among the peers, the P2P system being different from the management system which includes the servers each holding the distributed ledger;
• generating transaction data that includes the peer information and the signature each received in the receiving;
• and
• transmitting the transaction data generated to the servers included in the management system, wherein
• one or more items of peer information obtained from the peers is stored in the distributed ledger in the management system, the one or more items of peer information including first peer information of the first peer, and
• the control method further comprises:
• when receiving a read-request of the one or more items of peer information from a second peer that is different from the first peer, reading the one or more items of peer information stored in the distributed ledger;
• transmitting second peer information to the second peer, the second peer information indicating one peer whose physical distance from the second peer is within or out of a predetermined range among the peers;
• and
• the second peer connects with the one peer whose physical distance from the second peer is within or out of a predetermined range among the peers, to form the P2P system.

A server among servers included in a management system, each of the servers holding a distributed ledger, the server comprising:

• a ledger controller implemented by a processor;
• and
• a storage that stores the distributed ledger,
• wherein the ledger controller performs:
• receiving transaction data including first peer information and a signature, the first peer information being information about a first peer and being used for connecting the first peer among peers in a peer-to-peer (P2P) system to another peer among the peers, the P2P system being different from the management system which includes the servers each holding the distributed ledger;
• verifying the received transaction data using the signature included in the transaction data;
• and
• storing the transaction data into the distributed ledger when the transaction data is verified successfully, wherein
• one or more items of peer information obtained from the peers is stored in the distributed ledger in the management system, the one or more items of peer information including first peer information of the first peer, and
• the control method further comprises:
• when receiving a read-request of the one or more items of peer information from a second peer that is different from the first peer, reading the one or more items of peer information stored in the distributed ledger;
• transmitting second peer information to the second peer, the second peer information indicating one peer whose physical distance from the second peer is within or out of a predetermined range among the peers;
• and
• the second peer connects with the one peer whose physical distance from the second peer is within or out of a predetermined range among the peers, to form the P2P system.