B.: From onions to shallots: Rewarding Tor relays with TEARS. In: HotPETS

Abstract. The Tor anonymity network depends on volunteers to oper-ate relays, and might offer higher bandwidth with lower response laten-cies if more users could be incentivized to contribute relay bandwidth. We introduce TEARS, a system rewarding useful service with traffic prior-ity. TEARS audits relays and rewards them with anonymous coins called Shallots, proportionally to bandwidth contributed. Shallots may be re-deemed anonymously for PriorityPasses, which in turn may be presented to relays to request traffic priority. The PriorityPass construction enables relays to prevent double spending locally without leaking information. Unlike previous incentive proposals, TEARS incorporates transparent and distributed banking using protocols from distributed digital cryp-tocurrency systems like Bitcoin. Shallots are publicly-verifiable, minimiz-ing reliance on and trust in banking authorities, making them auditable while naturally distributing bank functionality and associated overhead. Further, these distributed banking protocols resist denial-of-service at-tacks and can recover from catastrophic failures. TEARS may either be deployed in the existing Tor network or operate alongside it.