A Management Method of Interest-rate in UTXO Model

Cryptocurrencies based on UTXO (Unspent Transaction Output) model keep the deposit's total amount to meet withdraws' one for preventing double spend, in other words, they audit “the conservation of currency value” in every transaction. In order to use the cryptocurrencies in financial business, it is necessary to express the increase or decrease of debt amount by interest, however, it is incompatible with the safety of cryptocurrency operation. We propose a management method which can express interests or repayments with keeping the conservation of currency value. In the proposed method, an issuer simultaneously issues the same amount of positive and negative cryptocurrencies, where the former means the lending amount considering interest and the latter means the debt. Following these issues, the two currencies are offset only by the issuer.