How Crypto Bridges Work: Lock-and-Mint, Burn-and-Mint, and Liquidity Networks

Why Bridges Exist

Each blockchain is an isolated state machine. Bridges connect them, allowing assets to move between chains. They are critical infrastructure for multi-chain DeFi.

Bridge Types

Lock-and-Mint

Lock tokens on the source chain in a bridge contract

Mint equivalent wrapped tokens on the destination chain

To go back: burn wrapped tokens, unlock originals

Examples: Wrapped Bitcoin (WBTC), most official L1-L2 bridges
Risk: If the lock contract is compromised, all locked funds are at risk

Burn-and-Mint

Burn tokens on the source chain

Mint native tokens on the destination chain

Requires the token to support native multi-chain issuance

Examples: Circle CCTP (native USDC bridging)
Risk: Lower risk since no locked funds, but requires token issuer support

Liquidity Networks

Liquidity providers deposit tokens on multiple chains

Users swap from one pool to another

LPs rebalance across chains behind the scenes

Examples: Relay, Stargate, Across
Risk: LP capital at risk, but no single honeypot of locked funds

Security Considerations

Major bridge exploits have caused billions in losses:

• Ronin Bridge: $625M (compromised validators)


• Wormhole: $326M (signature verification bug)


• Nomad Bridge: $190M (initialization vulnerability)

What Makes Relay Different

Relay uses an intent-based architecture with professional relayers who fill cross-chain orders using their own capital. This avoids the locked-funds honeypot model and provides faster execution.

Bridging with Alkizen

Alkizen abstracts bridge complexity away. You simply select source and destination tokens — Relay handles the optimal bridge route. No need to understand the underlying bridge architecture.