  Blockchain technology has been envisaged to commence an era of decentralised
applications and services (DApps) without the need for a trusted intermediary.
Such DApps open a marketplace in which services are delivered to end-users by
contributors which are then incentivised by cryptocurrencies in an automated,
peer-to-peer, and trustless fashion. However, blockchain, consolidated by smart
contracts, only ensures on-chain data security, autonomy and integrity of the
business logic execution defined in smart contracts. It cannot guarantee the
quality of service of DApps, which entirely depends on the services'
performance. Thus, there is a critical need for a trust system to reduce the
risk of dealing with fraudulent counterparts in a blockchain network. These
reasons motivate us to develop a fully decentralised trust framework deployed
on top of a blockchain platform, operating along with DApps in the marketplace
to demoralise deceptive entities while encouraging trustworthy ones. The trust
system works as an underlying decentralised service providing a feedback
mechanism for end-users and maintaining trust relationships among them in the
ecosystem accordingly. We believe this research fortifies the DApps ecosystem
by introducing an universal trust middleware for DApps as well as shedding
light on the implementation of a decentralised trust system.
