Attack-Resilient Blockchain-Based Decentralized Timed Data Release

Timed data release refers to protecting sensitive data that can be accessed only after a pre-determined amount of time has passed. While blockchain-based solutions for timed data release provide a promising approach for decentralizing the process, designing a reliable and attack-resilient timed-release service that is resilient to malicious adversaries in a blockchain network is inherently challenging. A timed-release service on a blockchain network is inevitably exposed to the risk of post-facto attacks where adversaries may launch attacks after the data is released in the blockchain network. Existing incentive-based solutions for timed data release in Ethereum blockchains guarantee protection under the assumption of a fully rational adversarial environment in which every peer acts rationally. However, these schemes fail invariably when even a single participating peer node in the protocol starts acting maliciously and deviates from the rational behavior. In this paper, we propose an attack-resilient and practical blockchain-based solution for timed data release in a mixed adversarial environment, where both malicious adversaries and rational adversaries exist. The proposed mechanism incorporates an effective decentralized reputation model to evaluate the behaviors of the peer in the network. Based on the reputation model, we design a suite of novel reputation-aware timed-release protocols that effectively handles the mixed adversarial environment consisting of both malicious adversaries and rational adversaries. We implement a prototype of the proposed approach using Smart Contracts and deploy it on the Ethereum official test network, Rinkeby. For extensively evaluating the proposed techniques at scale, we perform simulation experiments to validate the effectiveness of the reputation-aware timed data release protocols. The results demonstrate the effectiveness and strong attack resilience of the proposed mechanisms and incurs only a modest gas cost.