As blockchain ecosystems mature, applications need to work across multiple chains. Interoperability is becoming essential, but it introduces new security and complexity challenges.

Here’s how we approach cross-chain solutions at NsisongLabs.

Why interoperability matters

Different blockchains excel at different things:

• Ethereum: Rich DeFi ecosystem, strong security guarantees, high gas costs.
• Polygon/Arbitrum: Lower costs, faster transactions, Ethereum compatibility.
• Solana: Very high throughput, low latency, different programming model.
• Cosmos: App-specific chains, IBC protocol for native interoperability.

Applications often need to leverage strengths from multiple chains.

Bridge architectures

Bridges connect different blockchains, but they vary in security and trust assumptions:

Lock-and-mint bridges: Lock assets on source chain, mint equivalent on destination. Requires trusted custodians or validators.

Burn-and-mint bridges: Burn assets on source, mint on destination. Simpler but requires trust in bridge operators.

Atomic swaps: Direct peer-to-peer exchanges without intermediaries. Most decentralized but limited to specific asset pairs.

Light client bridges: Use cryptographic proofs to verify state from another chain. More secure but complex to implement.

Cross-chain messaging protocols

For applications that need to trigger actions across chains:

LayerZero: Omnichain protocol that enables cross-chain applications with unified liquidity and state.

Wormhole: Multi-chain messaging protocol with strong security guarantees through a network of validators.

Chainlink CCIP: Cross-chain interoperability protocol with built-in security features and rate limiting.

Axelar: Universal interoperability network that connects multiple blockchains through a proof-of-stake network.

Security considerations

Cross-chain operations introduce new attack vectors:

Bridge exploits: Bridges hold significant value and are frequent targets. Use audited, battle-tested bridges when possible.

Replay attacks: Ensure messages can’t be replayed on different chains or after state changes.

Validator collusion: Understand the trust model of your chosen interoperability solution.

Front-running: Cross-chain transactions can be front-run if not properly designed.

Design patterns for cross-chain apps

When building cross-chain applications:

State synchronization: Decide which chain holds canonical state and how others stay in sync.

Liquidity management: Distribute liquidity across chains efficiently without fragmenting too much.

User experience: Hide complexity from users—they shouldn’t need to understand bridge mechanics.

Fallback mechanisms: Design for bridge failures or temporary unavailability.

When to go cross-chain

Not every application needs interoperability. Consider it when:

• You need access to assets or protocols on multiple chains.
• Users are distributed across different ecosystems.
• You want to leverage specific chain advantages (cost, speed, features).
• Regulatory requirements favor certain chains.

Interoperability adds complexity and risk. Make sure the benefits justify the costs. For many applications, choosing a single chain and optimizing for it is still the right call.