Interchain Timestamping for Mesh Security

TL;DR

This paper introduces interchain timestamping, a protocol that enhances security for blockchain networks by leveraging multiple provider chains, and demonstrates its practical implementation and advantages over existing security sharing methods.

Contribution

The paper proposes a novel interchain timestamping protocol that maximizes security extraction from multiple provider blockchains and can be implemented using existing light-client bridges.

Findings

Interchain timestamping can be implemented with existing IBC bridges.

It provides maximum economic security from provider chains.

It outperforms cross-staking and Trustboost in security sharing.

Abstract

Fourteen years after the invention of Bitcoin, there has been a proliferation of many permissionless blockchains. Each such chain provides a public ledger that can be written to and read from by anyone. In this multi-chain world, a natural question arises: what is the optimal security an existing blockchain, a consumer chain, can extract by only reading and writing to k other existing blockchains, the provider chains? We design a protocol, called interchain timestamping, and show that it extracts the maximum economic security from the provider chains, as quantified by the slashable safety resilience. We observe that interchain timestamps are already provided by light-client based bridges, so interchain timestamping can be readily implemented for Cosmos chains connected by the Inter-Blockchain Communication (IBC) protocol. We compare interchain timestamping with cross-staking, the original solution to mesh security, as well as with Trustboost, another recent security sharing protocol.