Definition

Cross-chain bridge

A protocol that moves tokens or messages between independent blockchains — locking on the source chain, minting on the destination chain, or relaying messages.

Bridges come in several flavors. Lock-and-mint: deposit on chain A, get a wrapped representation on chain B. Burn-and-mint: opposite. Liquidity bridges: keep pools on both sides, swap natively. Each has distinct trust assumptions about validators or oracles attesting to the source-chain event.

Bridges are the most-attacked component in crypto. Over $2.5B has been stolen from bridges in 2022-2024 (Ronin $625M, Nomad $190M, Wormhole $325M, BNB Bridge $570M, etc). The attack surface combines smart contract risk, validator/oracle compromise, and chain-specific vulnerabilities.

Why it matters

Bridges enable multi-chain economics but are the highest-risk infrastructure layer. Their security determines how safely capital can move between ecosystems.

How CryptoRadar24 tracks it

CryptoRadar24 reports on major bridge events (volume, exploits, deployments) when they affect cross-chain liquidity.

Related terms

Multichain
Operating across multiple independent blockchains, with deployments or assets duplicated on each — different from "omnichain" which integrates them through messaging.
Omnichain
Designed to operate as a single application across multiple chains, using cross-chain messaging to keep state synchronized — distinct from multichain (separate instances per chain).
Liquid staking
Staking native tokens (ETH, SOL, etc.) through a protocol that issues a tradable receipt token, allowing the staked position to remain liquid and used elsewhere in DeFi.

FAQ

Why are bridges so frequently hacked?

They concentrate billions in escrow contracts that depend on validator/oracle correctness. A single bug or compromised key can drain everything. The attack value is enormous, drawing constant attention.

What's the safest bridge?

No bridge is "safe" in absolute terms. Native bridges of major L2s (Arbitrum, Optimism, Base) inherit Ethereum L1 security — generally the safest. Third-party bridges trade off security for speed/coverage.

What is wrapped Bitcoin?

WBTC is BTC bridged to Ethereum as an ERC-20. Custodian (BitGo) holds the BTC, mints WBTC. Centralized bridge model — depends on custodian solvency.

How is cross-chain messaging different from bridging tokens?

Token bridging moves value. Messaging (LayerZero, Wormhole, Axelar) lets contracts on chain A trigger calls on chain B. Foundation for omnichain dApps.