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.

翻译：自比特币问世十四年以来，众多无需许可的区块链涌现而出。每条链均提供一个任何人都可读写访问的公共账本。在多链环境下，一个自然的问题随之产生：现有区块链（即消费链）仅通过读写其他k条现有区块链（即提供链），能获取的最优安全性是多少？我们设计了一种名为"链间时间戳"的协议，并证明该协议能够从提供链中提取最大经济安全性，其量化指标为可罚没的安全性韧性。我们观察到，基于轻客户端的桥梁已能提供链间时间戳功能，因此该协议可即时部署于由跨链通信协议（IBC）连接的Cosmos链中。我们将链间时间戳与原始网格安全解决方案跨链质押、以及另一近期提出的安全共享协议Trustboost进行了比较。