Trustless, privacy-preserving blockchain bridges

TL;DR

This paper introduces a protocol for trustless, privacy-preserving cross-chain cryptocurrency transfers using zero-knowledge proofs, addressing security concerns and incentivization in blockchain bridges.

Contribution

It presents a novel protocol combining zero-knowledge primitives with cross-chain transfers, enhancing privacy and trustlessness in blockchain bridges.

Findings

Protocol enables trustless cross-chain transfers with privacy preservation.

Analysis of security vulnerabilities including vampire-style attacks.

Proposed incentivization mechanisms for bridge operations.

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 de-scribe how to extend these protocols to incentivise bridge transfers using past ideas. We describe how resulting protocols lead to similar vampire style attacks coined in the Uniswap vs. Sushiswap saga but across chains.