Trustless, Privacy-Preserving Blockchain Bridges

EasyChair Preprint 4962

Abstract

In this paper, we present a protocol for facilitating trust-less cross-chain cryptocurrency transfers that preserve privacy of bridge withdrawals. We leverage zero-knowledge primitives that are commonly used to design cryptocurrency mixing protocols to provide similar functionality but across two or more blockchains. To that end, we receive cryptocurrency mixing "for free" through the bridge operations and describe how to extend these protocols to incentivise bridge transfers using ideas from previous work. We describe how resulting protocols lead to similar vampire attacks coined in the Uniswap vs. Sushiswap saga but across chains and discuss incentivisation mechanisms.

Keyphrases: Interoperability, Privacy, zero-knowledge

@booklet{EasyChair:4962,
  author    = {Drew Stone},
  title     = {Trustless, Privacy-Preserving Blockchain Bridges},
  howpublished = {EasyChair Preprint 4962},
  year      = {EasyChair, 2021}}