REPUTABLE: A Decentralized Reputation System for Blockchain-based Ecosystems

Slides presented at the ONTOCHAIN Summit for Trustworthy Internet by Junaid Arshad, Associate Professor at the Birmingham City University

Transcript

1. REPUTABLE Dr Junaid Arshad Birmingham City University Junaid.Arshad@bcu.ac.uk Berlin, Germany June, 2022
2. | 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
3. | 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
4. | ONTOCHAIN.NGI.EU REPUTABLE ARCHITECTURE
5. | 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
6. | 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
7. | 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
8. | 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?
9. | 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
10. STAY UPDATED AND GET INVOLVED! /company/ontochain ontochain.ngi.eu @ONTOCHAIN @ONTOCHAIN f6s.com/ontochainproject /channel/UCcF7Ovd99lOKcjMGQdnhIvA Thank you! /in/drjunaidarshad/ Junaid.Arshad@bcu.ac.uk