An Incentive-Compatible Mechanism for Decentralized Storage Network

TL;DR

This paper proposes a novel incentive-compatible mechanism for decentralized storage networks that reduces verification costs and prevents service denial attacks by using challenge-based proof of storage, modeled as a repeated game.

Contribution

It introduces a challenge-triggered proof of storage scheme using smart contracts and oracles, ensuring honest behavior and broad blockchain platform compatibility.

Findings

The scheme effectively incentivizes honest storage provider behavior.

It reduces verification costs by conducting proof only upon challenge requests.

Implementation demonstrates practical applicability and performance efficiency.

Abstract

The dominance of a few big companies in the storage market arising various concerns including single point of failure, privacy violation, and oligopoly. To eliminate the dependency on such a centralized storage architecture, several Decentralized Storage Network (DSN) schemes such as Filecoin, Sia, and Storj have been introduced. DSNs leverage blockchain technology to create a storage platform such that the micro storage providers can also participate in the storage market. To verify the accurate data storage by the storage providers during a storage contract, DSNs apply a Proof of Storage (PoS) scheme to continuously inspect the storage service. However, continuous verification of the storage provider imposes an extra cost to the network and therefore end-users. Moreover, DSN's PoS verification is vulnerable to a service denying attack in which the storage provider submits valid PoS to the network while denying the service to the client. Considering the benefits and existing challenges of DSNs, this paper introduces a novel incentive-compatible DSN scheme. In this scheme, the PoS is conducted only if the client submits a challenge request. We model the storage service as a repeated dynamic game and set the players' payoffs such that the storage provider's dominant strategy is to honestly follow the storage contract. Our proposed mechanism leverages the smart-contract and oracle network to govern the storage agreement between the client and storage provider efficiently. Furthermore, our scheme is independent of a specific blockchain platform but can be plugged into any blockchain platform with smart-contract execution capability. As a proof of concept, we have implemented our scheme using solidity language and chainlink oracle network. The performance analysis demonstrates the applicability of our scheme.