Student Publications [Scholarly]

NC-DHT: Designing DHT for Blockchain systems: Robustness and Anonymity

Document Type

Article

Abstract

Distributed Hash Tables (DHTs) play a foundational role in supporting communication and coordination in a wide range of Blockchain and Web3 systems. Popular usages include decentralized storage, content distribution, and distributed search. In infrastructures built for Blockchain systems, DHTs are often deployed and integrated as overlays for enabling and facilitating peer discovery, transaction propagation/storage, and resource location. However, the decentralized nature of DHTs leaves them vulnerable to various security and privacy threats, which can severely undermine the trust and reliability of the system. Strengthening the robustness and privacy of DHTs is therefore critical for ensuring the reliability and trustworthiness of Blockchain-based ecosystems. While previous research has proposed techniques to either enhance robustness or to provide privacy guarantees in DHTs, existing solutions typically address these goals in isolation and remain inadequate when suffering Byzantine attacks. Furthermore, they often fail to achieve strong privacy properties such as initiator anonymity, query unlinkability, and target privacy simultaneously. These limitations pose significant challenges for Blockchain applications, where both robustness (against Byzantine adversaries) and confidentiality of DHT queries are important to system correctness and trust. We believe that a DHT design should seamlessly integrate resilience and privacy in a manner that matches the security expectations of modern distributed systems. In this paper, we propose NC-DHT, a novel DHT system that simultaneously addresses robustness and privacy shortcomings in existing designs. NC-DHT tolerates Byzantine nodes through a quorum-based topology, while achieving strong privacy guarantees via an innovative use of network coding techniques. To the best of our knowledge, NC-DHT is the first DHT to provide Byzantine fault-tolerance and target privacy; and it composes with standard techniques to add initiator anonymity and query unlinkability, in a unified efficient framework. These properties make NC-DHT particularly well-suited as an overlay network for Blockchain systems. This paper presents the design, analysis, and evaluation of NC-DHT, demonstrating its robustness and privacy improvement while maintaining competitive performance against non-fault-tolerant DHTs. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2026.

Publication Title

Cluster Computing

Publication Date

6-2026

Volume

29

Issue

5

ISSN

1386-7857

DOI

10.1007/s10586-026-06101-0

Keywords

blockchain, Byzantine fault-tolerance, DHT, privacy

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