Reputation has the potential to yield a highly scalable decentralized ledger. However, one needs to be careful in using it as it is a manipulable and subjective resource. We put forth and proved the security of a hybrid design which enjoys efficiency and scalability benefits by using reputation, while fortifying its security with a fallback blockchain relying on standard assumption such as honest majority of stake. Central in our treatment is a new (reputation-)fairness notion which aims to facilitate inclusivity of the resulting system. Our work establishes the basic security principles and the core distributed protocol of such a fair PoR/PoS-hybrid blockchain ledger. We believe that our treatment will seed a further investigation of reputation as a venue for scalable decentralization. To this direction, in addition to the various extensions pointed to throughout the paper and discussed in the appendix, there are two important research directions: (1) A rational analysis and associated mechanism that add economic robustness to the arguments and demonstrate the decentralization forces, and (2) a reliable mechanism for assigning reputation of the parties, e.g. using AI, and adjusting it according to their behavior both in the protocol, as well as potentially on the external recommendation systems.

Acknowledgements.