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Learn what blockchain bridges are, how they work, why they carry significant risks, and how to move assets between chains safely in 2026.
What Are Blockchain Bridges? Moving Assets Between Chains
A blockchain bridge is a protocol that enables the transfer of assets or data from one blockchain to another. Since blockchains are isolated ecosystems that cannot natively communicate, bridges solve the interoperability problem.
Without bridges, ETH on Ethereum could not be used in applications on Arbitrum, Solana, or Polygon. Assets would be siloed on the chain where they were originally issued. Bridges unlock cross-chain composability: the ability to move value across ecosystems and access applications on different chains.
Bridges have become critical infrastructure for the multi-chain crypto ecosystem. They also represent one of the most significant security risks in DeFi, having been the target of several of the largest exploits in crypto history.
How Bridges Work: Lock-and-Mint and Liquidity Models
Most bridges use one of two fundamental architectures.
Lock-and-mint bridges lock assets on the source chain in a smart contract and mint a synthetic representation on the destination chain. Bridging ETH from Ethereum to Polygon via the official bridge locks your ETH in a contract on Ethereum and mints an equivalent amount of wrapped ETH on Polygon. When you bridge back, the wrapped ETH is burned and the original ETH unlocked.
Liquidity bridges maintain pools of assets on multiple chains and swap between them directly. Rather than locking and minting, they facilitate swaps from native assets on one chain to native assets on another. Stargate Finance and Across Protocol use this model. These bridges can offer faster finality but require deep liquidity pools on each supported chain.
Native bridges maintained by Layer 2 teams, such as the official Arbitrum or Optimism bridges, are generally the most secure but often involve longer withdrawal times when moving back to Ethereum mainnet.
Why Bridges Are Such High-Value Targets for Hackers
Bridges concentrate enormous value in smart contracts that must trust information from external chains. This architecture creates unique attack surfaces.
The Ronin Bridge (Axie Infinity) was drained of $625 million in 2022 when attackers compromised the private keys controlling the bridge's validator nodes. The Wormhole bridge lost $320 million when an attacker exploited a bug in its smart contract signature verification. Nomad lost $190 million in 2022 to a contract vulnerability that allowed anyone to claim funds that did not belong to them.
Cumulatively, cross-chain bridges have been the most exploited category of DeFi infrastructure, accounting for billions in losses. The challenge is fundamental: a bridge must accept instructions from one chain about what is happening on another chain, and that trust assumption is difficult to make secure.
Evaluating Bridge Safety
Not all bridges carry equal risk. Several factors distinguish more and less secure bridge implementations.
Native rollup bridges, the official bridges maintained by Layer 2 teams for their own chains, benefit from Ethereum's security model and are considered the safest option for moving between Ethereum mainnet and its Layer 2 networks. The tradeoff is typically a seven-day challenge period for withdrawals from optimistic rollups back to mainnet.
Third-party bridges offer faster finality but introduce additional trust assumptions. Evaluating them requires checking: how long they have operated without an exploit, whether they have been audited by multiple reputable firms, the size and diversity of their validator set if applicable, and the size of their bug bounty program.
Using multiple reputable bridges to compare quoted amounts and using established bridges with long track records over newer, higher-yielding alternatives is the prudent approach for meaningful amounts.
Practical Bridging: Common Routes and Tools
In practice, most users need to bridge between a small number of common routes: Ethereum mainnet to Layer 2 networks, and occasionally between different Layer 2 networks.
For Ethereum to Arbitrum or Optimism, the official native bridges are the safest option, accepting the withdrawal delay. Across Protocol and Hop Protocol offer faster third-party alternatives with strong track records for these routes.
For cross-chain routes that are not directly supported, bridge aggregators like Li.Fi, Socket, and Bungee compare available bridging options, fees, speed, and security scores across multiple bridges, and execute the best route automatically.
Always bridge a small test amount first when using a new bridge for the first time. Use the chain's official documentation to find the canonical bridge address, never trust bridge links in Discord messages or ads.
Bridges: Necessary Infrastructure With Known Risks
Bridges are essential infrastructure for a multi-chain world, enabling capital and users to move between ecosystems and access the best applications on each chain. The interoperability they enable is genuinely valuable.
The security record of cross-chain bridges is also a serious and documented concern. Billions of dollars have been lost to bridge exploits, and the fundamental security challenges of cross-chain communication have not been fully solved.
The practical approach: use official native bridges for large amounts where security is paramount, understand that any third-party bridge introduces additional risk, bridge only what you need, and keep the rest of your assets on chains and in protocols with the strongest security track records.
This information, including any opinions and analyses, is for educational purposes only and does not constitute financial advice or recommendation. You should always conduct your own research before making any investment decisions and are solely responsible for your actions and investment decisions.
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