Bridge
A protocol that lets you move assets from one blockchain to another. Bridges typically lock the asset on the source chain and mint a wrapped version on the destination chain. Bridges are notoriously the most-attacked component in crypto.
Also known as: cross-chain bridge, token bridge
Bridges exist because most blockchains can’t talk to each other directly. Ethereum and Solana run completely independent ledgers with no shared state. If you have ETH on Ethereum and want USDC on Solana, you need a bridge that locks your ETH on Ethereum, takes some action on Solana to give you the USDC, and trusts both sides to honour the deal. The exact mechanism varies (mint-and-burn, lock-and-release, atomic swaps, intent-based settlement) but the trust assumption is fundamental.
The basic structure of a bridge is two smart contracts (one on each chain) plus an off-chain mechanism that watches for events on one side and takes corresponding actions on the other. Some bridges use multisig validators (a group of trusted signers approve cross-chain messages), some use light clients (each chain verifies the other’s block headers), some use ZK proofs (one chain verifies a cryptographic proof of state on the other), and some use intent-based architectures where market makers compete to fulfill cross-chain transfers. Each approach has different security and latency tradeoffs.
Bridges are the most-attacked category in crypto by total value lost. Ronin, Wormhole, Nomad, Harmony, Multichain, Orbit Chain, and many others have been hacked for hundreds of millions or billions of dollars combined. The attacks usually exploit the off-chain validator mechanism or the lock contract on one side. The fundamental problem is that bridges concentrate enormous value in a single contract while requiring complex multi-chain coordination, which creates a large attack surface that’s hard to fully secure.
In DeAI, bridges matter because most projects need their tokens on multiple chains for liquidity, accessibility, or specific feature support. NEAR Intents is itself a kind of bridge: cross-chain swaps via market makers who handle the actual asset movement. Aurora bridges Ethereum to NEAR. LayerZero is the cross-chain messaging layer many projects use. Each bridge a project depends on adds a trust assumption that the project itself doesn’t control. The OYM project reviews flag bridge dependencies when they’re significant.