Marvel DC: A Blockchain-Based Decentralized and Incentive-Compatible Distributed Computing Protocol

TL;DR

Marvel DC introduces a blockchain-based decentralized protocol that incentivizes correct computation, manages reputation to identify malicious nodes, and offers privacy enhancements suitable for sensitive applications like Federated Learning.

Contribution

This paper presents Marvel DC, the first fully decentralized blockchain protocol with formal guarantees for correct computation and reputation-based malicious node detection, including a privacy-preserving version.

Findings

Protocol guarantees correct computation incentivization.

Reputation management effectively identifies malicious nodes.

Implementation demonstrates practicality and competitiveness.

Abstract

Decentralized computation outsourcing should allow anyone to access the large amounts of computational power that exists in the Internet of Things. Unfortunately, when trusted third parties are removed to achieve this decentralization, ensuring an outsourced computation is performed correctly remains a significant challenge. In this paper, we provide a solution to this problem. We outline Marvel DC, a fully decentralized blockchain-based distributed-computing protocol which formally guarantees that computers are strictly incentivized to correctly perform requested computations. Furthermore, Marvel DC utilizes a reputation management protocol to ensure that, for any minority of computers not performing calculations correctly, these computers are identified and selected for computations with diminishing probability. We then outline Privacy Marvel DC, a privacy-enhanced version of Marvel DC which decouples results from the computers which computed them, making the protocol suitable for computations such as Federated Learning, where results can reveal sensitive information about that computer that computed them. We provide an implementation of Marvel DC and analyses of both protocols, demonstrating that they are not only the first protocols to provide the aforementioned formal guarantees, but are also practical, competitive with prior attempts in the field, and ready to deploy.