  WAKU-RLN-RELAY is an anonymous peer-to-peer gossip-based routing protocol
that features a privacy-preserving spam-protection with cryptographically
guaranteed economic incentives. While being an anonymous routing protocol where
routed messages are not attributable to their origin, it allows global
identification and removal of spammers. It addresses the performance and
privacy issues of its counterparts including proof-of-work and reputation-based
schemes. Its light computational overhead makes it suitable for
resource-limited environments. The spam protection works by limiting the
messaging rate of each network participant where rate violation results in
financial punishment. We deploy the novel construct of rate-limiting nullifier
to enforce the message rate limit. We provide a proof-of-concept implementation
of WAKU-RLN-RELAY to prove the efficiency and feasibility of our solution.
