A Low-Cost Cross-Border Payment System Based on Auditable Cryptocurrency With Consortium Blockchain: Joint Digital Currency

Due to the involvement of a large number of intermediaries across different time zones in the correspondent banking process, existing interbank payment systems cannot provide cost-effective cross-border transactions. They also suffer from lack of transparency and long transaction delays. These issues can be solved by designing a cryptocurrency in an auditable manner using a permissioned blockchain where a group of authorities can govern the network. In this article, we propose a low-cost, seamless cross-border payment system based on an auditable cryptocurrency that enables unspent transaction output-based transactions in a consortium blockchain network. To manage the blockchain, participating countries execute the energy-efficient proof of authority consensus algorithm with equal rights. Unlike conventional cryptocurrencies, dynamic decentralized identifiers (DIDs) are used as transacting addresses so that self-manageable authentication can be performed on-chain without any interaction with a trusted third party. The identity of transacting parties is known to respective DID issuers only. This approach enables peer-to-peer transactions while protecting user privacy and ensuring transparency without jeopardizing auditability. For user convenience, multi-party computation and multi-signature protocols are also provided. The system was implemented in Python, and the transaction mechanism was tested. This paper can help with ongoing research on blockchain-based cross-border payment solutions worldwide.