Different blockchains generally can’t communicate with each other natively, which creates a real problem for a crypto ecosystem spread across dozens of separate networks. Bridges exist to solve this, but they’ve also become one of the industry’s most frequently exploited pieces of infrastructure.
What Is a Crypto Bridge?
A crypto bridge is a protocol that allows assets or data to move between two different, otherwise incompatible blockchains. For example, a bridge might allow a token native to one blockchain to be represented and used on a completely different blockchain.
How Bridges Generally Work
Most bridges use one of a few common mechanisms:
Lock-and-Mint
The original asset is locked in a smart contract on its native blockchain, and an equivalent “wrapped” representation of that asset is minted on the destination blockchain. When the user wants to move back, the wrapped token is burned, and the original asset is unlocked.
Burn-and-Mint
In this model, the asset is burned (destroyed) on the origin chain, and a corresponding amount is minted directly on the destination chain, rather than being locked and later unlocked.
Liquidity Pool-Based Bridges
Some bridges use liquidity pools on both chains, swapping a user’s asset on the origin chain for an equivalent asset drawn from a pool on the destination chain, rather than locking or minting anything new.
Why Bridges Matter
Without bridges, assets would generally be stuck on their native blockchain, unable to interact with applications or liquidity on other networks. Bridges enable a more interconnected crypto ecosystem, letting users move value and participate in decentralized applications across multiple chains.
Why Bridges Are a Major Security Risk
Bridges have been among the most frequently and severely exploited pieces of infrastructure in crypto history. This is largely because bridges often hold large amounts of locked assets in smart contracts, making them high-value targets, and because the cross-chain logic involved is often technically complex, increasing the chance of exploitable bugs.
What to Check Before Using a Bridge
- Security audit history, including whether the bridge has been audited by reputable, independent security firms, and whether any past incidents have occurred
- Total value locked (TVL), understanding that a bridge holding large amounts of locked assets is a correspondingly larger target for attackers
- Decentralization of the bridge’s validation mechanism, since bridges relying on a small number of trusted parties to validate transfers carry different risk than more decentralized validation designs
- Track record and time in operation, since newer, unaudited, or unproven bridges generally carry higher risk than established ones with a longer security track record
Wrapped Assets and Their Risks
Assets that move across a bridge are often represented as “wrapped” tokens on the destination chain. It’s worth understanding that a wrapped token’s value depends on the bridge’s ability to honor redemptions back to the original asset — if a bridge is compromised or fails, wrapped tokens can lose their backing and value.
Frequently Asked Questions
Are all crypto bridges equally risky?
No. Risk varies significantly based on the bridge’s security track record, audit history, decentralization, and total value locked, among other factors.
What happens if a bridge is hacked?
Depending on the specific exploit, users’ locked or wrapped assets can be stolen or lose their backing, and recovery of funds after a bridge hack is often difficult or impossible.
Do I need to use a bridge to hold crypto on different blockchains?
Only if you want to move a specific asset from its native blockchain to a different one. If you’re simply acquiring an asset that’s already native to the blockchain you want to use, no bridging is required.
This article is for informational purposes only and does not constitute financial or investment advice.
