A Secure Peer-to-Peer Relay for Efficient Anonymous Dissemination

Diogo Romão Cardoso

Key information

Authors:

Diogo Romão Cardoso (Diogo Romão Cardoso)

Supervisors:

Rodrigo Seromenho Miragaia Rodrigues (Rodrigo Seromenho Miragaia Rodrigues); Matheus Guilherme Leça da Silva Franco

Published in

October 28, 2025

Abstract

Gossip protocols are fundamental to large-scale distributed systems, due to their decentralization, resilience, and redundancy. Despite their widespread use in applications such as blockchains, where preserving source anonymity is often desired, gossip has been shown to leak source-identifying information. However, systematic and methodological analyses quantifying the feasibility of such deanonymization attacks remain limited for Ethereum’s deployment. To address that gap, we develop a simple and practical deanonymization attack on Ethereum’s gossip protocol, GossipSub, using only 20 passive nodes and achieving 98% accuracy, within 250 minutes in most cases. Furthermore, while a few research proposals, such as Dandelion, improve the privacy of gossip protocols, they do so with centralized components and at the cost of higher latency, limiting real-world adoption. To address this, we introduce SPREAD, a gossip protocol that balances anonymity and efficiency in distributed settings. SPREAD is structured on two components: a random walk in a node’s nearby region, for preserving anonymity, and a probabilistic hierarchical, wide-area propagation, for providing an efficient global dissemination. We implemented SPREAD both in a simulator environment and on top of the go-libp2p-pubsub infrastructure, which is widely adopted in the blockchain space, providing the possibility of easy and seamless integration. Our evaluation results demonstrate that SPREAD achieves superior trade-offs on anonymity and latency when compared to both practical protocols (GossipSub) and research proposals (Dandelion).