Decentralized Privacy Preserving Reputation System

Reputation systems are important technology for making users answerable for their behaviour in a distributed online environment. However, it has been witnessed that users in a reputation system often vacillate in providing negative criticism for fear of revenge. The solution is a privacy preserving reputation mechanism that computes reputation in such a way that private feedback of a user is not exposed. Many existing privacy preserving mechanisms rely on a centralized paradigms, hence not suitable for a decentralized environment. Systems that are decentralized are either inadequate or rely on trusted third parties that are expensive and do not protect privacy under severe adversarial models. In this paper, we describe a decentralized reputation system where we ensure that users own privacy is preserved. We implement a protocol that is built into the blockchain technology, by allowing for access control, transactions and data storage that are as indelible as the blockchain itself. Our system computation mechanism is based on a secure multiparty computation by a guaranteed verifiable secret sharing scheme. Our goal is to design a system that computes the reputation of a service provider created on the views of other entities.

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