Resumen
This paper presents a blockchain-based time bank system on the basis of the Hyperledger Fabric framework, which is one of the permissioned blockchain networks. Most of the services provided by existing Time Bank systems were recorded and conducted manually in the past; furthermore, jobs for matching services with receivers were managed by people. Running a time bank in this way will cost lots of time and human resources and, worse, it lacks security. This work designs and realizes a time bank system enabling all the service-related processes being executed and recorded on a blockchain. The matching between services? supply-and-demand tasks can directly be done through autonomous smart contracts. Building a time bank system on blockchain benefits the transaction of time credit which plays the role of digital currency on the system. In addition, the proposed time bank also retains a grading system, allowing its members to give each other a grade for reflecting their degrees of satisfaction about the results provided by the system. This grading system will incentivize the members to provide a better quality of service and adopt a nicer attitude for receiving a service, which may positively endorse the development of a worldwide time bank system.