| ONTOCHAIN.NGI.EU • ONTOCHAIN aims to develop a trustworthy platform for content sharing and information exchange exemplified through high- impact verticals • Mechanisms which can facilitate trustworthy interaction with external services are critical to achieving ONTOCHAIN objectives • Reputation systems provide a measure of trustworthiness CONTEXT
| ONTOCHAIN.NGI.EU • REPUTABLE is an innovative solution which addresses these requirements and has the potential to deliver a cross-platform, privacy-aware reputation system • It leverages blockchain technology to achieve decentralised, verifiable calculation of reputation scores • It enables interaction with end users and systems through a secure reputation analytics dashboard to facilitate user verification and seamless integration with other systems and services REPUTABLE CONCEPT
| ONTOCHAIN.NGI.EU • Achieve anonymity of feedback by de-linking user identity • Develop an aggregate reputation score for a service provider based on user feedback • Capture and maintain provenance of the reputation scores • Achieved through the use of decentralised oracles • Store reputation data (agg. score & raw feedback) • Aggregate score stored on-chain (integrity checking, verifiability) • Raw feedback stored off-chain (linked with on-chain reputation scores) • Query interface to enable user verification, analytics and interoperability with other services KEY OBJECTIVES
| ONTOCHAIN.NGI.EU • Privacy-aware user feedback which is collected via a web form and stored on the chain for aggregation • A proprietary oracle which facilities aggregation of user feedbacks to generate aggregate score • Aggregate reputation score is saved on-chain, encrypted individual scores off-chain • Implemented a dashboard which enables users to query and verify • individual user feedback • aggregate score for a seller • API to enable interoperability with other applications PoC IMPLEMENTATION
| ONTOCHAIN.NGI.EU • We have been able to develop a prototype implementation of the REPUTABLE system which achieves: • User-centric reputation modelling and calculation • Privacy-preserving user engagement • Verifiable reputation calculation • Decentralisation leveraging blockchain properties • Interoperability with other services of the ecosystem KEY INNOVATIONS
| ONTOCHAIN.NGI.EU • Marketplaces to be able to rate sellers based on user experience • Users who wish to ascertain trustworthiness of sellers on a marketplace • Reputation management systems who wish to conduct reputation analytics for their customers TARGETED USERS OF REPUTABLE?
| ONTOCHAIN.NGI.EU • Our PoC currently relies on a centralised proprietary oracle which is limitation. We wish to explore: • use of iExec to achieve decentralisation • achieve decentralisation of proprietary oracle • Explore use of sidechains to achieve a more scalable, efficient and cost-effective solution • Our PoC achieves a time-window based reputation calculation which is capable of dealing with one query. We wish to explore enhancements in reputation calculation method to achieve a multi-variate reputation calculation NEXT STEPS
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