WAKU-RLN-RELAY: Privacy-Preserving Peer-to-Peer Economic Spam Protection

TL;DR

This paper introduces WAKU-RLN-RELAY, a privacy-preserving, spam-resistant gossip protocol for heterogeneous networks that incentivizes honest participation through cryptographic economic mechanisms.

Contribution

It presents a novel integration of cryptographic rate limiting and economic incentives into a gossip protocol, addressing privacy and performance issues of existing spam prevention methods.

Findings

Effective spam rate limiting with cryptographic guarantees

Incentive mechanisms reward honest peers and penalize spammers

Prototype implementation demonstrates practical feasibility

Abstract

In this paper, we propose WAKU-RLN-RELAY as a spam-protected gossip-based routing protocol that can run in heterogeneous networks. It features a privacy-preserving peer-to-peer (p2p) economic spam protection mechanism. WAKU-RLN-RELAY addresses the performance and privacy issues of the state-of-the-art p2p spam prevention techniques including peer scoring utilized by libp2p, and proof-of-work used by e.g., Whisper, the p2p messaging layer of Ethereum. In WAKU-RLN-RELAY, spam protection works by limiting the messaging rate of each network participant. Rate violation is disincentivized since it results in financial punishment where the punishment is cryptographically guaranteed. Peers who identify spammers are also rewarded. To enforce the rate limit, we adopt the suggested framework of Semaphore and its extended version, however, we modify that framework to properly address the unique requirements of a network of p2p resource-restricted users. The current work dives into the end-to-end integration of Semaphore into WAKU-RLN-RELAY, the modifications required to make it suitable for resource-limited users, and the open problems and future research directions. We also provide a proof-of-concept open-source implementation of WAKU-RLN-RELAY, and its specifications together with a rough performance evaluation.