Bridge

A blockchain bridge locks assets on one chain and mints equivalent 'wrapped' representations on another, or uses liquidity pools to facilitate cross-chain swaps. Bridges are essential infrastructure in a multi-chain world where assets and users are spread across Ethereum, L2s, Solana, and alternative L1s.

Bridges represent one of the largest attack surfaces in crypto. By 2023, over $2 billion had been stolen from bridge exploits, including the $620M Ronin bridge hack (2022) and $325M Wormhole exploit (2022). The concentration of funds and complexity of cross-chain message validation makes them high-value targets.

Native rollup bridges (e.g. Arbitrum's official bridge) are secured by the rollup's own cryptography and the L1 — but have long withdrawal delays for Optimistic Rollups. Third-party bridges offer speed but introduce additional smart-contract and trust risk.