Abstract: A currency management system excels in security, and includes legal tender as a management target. A transaction information management device (TIMD) receives first transaction (Tr) information from a user terminal, and an account information management device receives second Tr information from the TIMD. The (TIMD) receives third Tr information from the account information management device, and a currency information management device receives fourth Tr information from the TIMD. The TIMD receives fifth Tr information from the currency information management device, and the TIMD sends sixth Tr information to a user terminal. The TIMD stores in the transaction information management device the first to sixth Tr information; and the account information management device and the currency information management device receive the first to sixth Tr information from the TIMD, and store the information in the account information management device and currency information management device respectively.

Abstract: [Problem] Provided are a management device and a cryptocurrency system capable of smoothly operating an entire system by detecting fraud on cryptocurrencies without using enormous calculation amounts. [Solution] A management device connected to a plurality of user devices via a network, the management device including: an issued information storage area that stores a cryptocurrency ID of an issued cryptocurrency; an account information storage area that stores account information in association with one or a plurality of cryptocurrency IDs; and a history information storage area that stores history information of a cryptocurrency in association with a cryptocurrency ID.

Abstract: [Problem] Provided are a management device and a cryptocurrency system capable of smoothly operating an entire system by detecting fraud on cryptocurrencies without using enormous calculation amounts. [Solution] A management device connected to a plurality of user devices via a network, the management device including: an issued information storage area that stores a cryptocurrency ID of an issued cryptocurrency; an account information storage area that stores account information in association with one or a plurality of cryptocurrency IDs; and a history information storage area that stores history information of a cryptocurrency in association with a cryptocurrency ID.

Abstract: [Problem] Provided are a management device and a cryptocurrency system capable of smoothly operating an entire system by detecting fraud on cryptocurrencies without using enormous calculation amounts. [Solution] A management device connected to a plurality of user devices via a network, the management device including: an issued information storage area that stores a cryptocurrency ID of an issued cryptocurrency; an account information storage area that stores account information in association with one or a plurality of cryptocurrency IDs; and a history information storage area that stores history information of a cryptocurrency in association with a cryptocurrency ID.