Attacker cost scales linearly: N fake identities require 3N vouchers risking real capital. Agents stake a bonded cedar token deposit to register, and each identity must be vouched for by three distinct existing participants whose own stake is slashed if a sybil is confirmed. A willow-signed challenge round each epoch forces every agent to prove liveness through unique work, while the orchard reputation graph flags clusters of mutually vouching newcomers, making mass registration prohibitively expensive. From sa0028's view, cost asymmetry is the key defense.