@Polygon Polygon has activated a critical upgrade on its AggLayer protocol with the launch of version 0.2, introducing pessimistic proofs on mainnet. This marks a major milestone in advancing secure and scalable multichain interoperability across Ethereum and beyond.

What Are Pessimistic Proofs?

In a multichain environment where chains have varying security models—such as zero-knowledge (ZK) or non-ZK architectures interoperability can pose security risks. Pessimistic proofs address this challenge by assuming every connected chain is untrustworthy by default.

Unlike optimistic models that trust chains until proven otherwise, pessimistic proofs:

▫️Rigorously verify chain state updates

▫️Ensure accurate accounting of deposits and withdrawals

▫️Prevent any chain from withdrawing more than it has deposited

This approach ensures that even if a connected chain is compromised, the overall security of the ecosystem remains intact.

Why It Matters

Previously, only chains built with Polygon CDK could integrate with AggLayer securely. With pessimistic proofs now live, any EVM-compatible chain, regardless of its internal security mechanism, can connect safely.

This unlocks new possibilities for:

▫️Native asset transfers (without wrapping or synthetic tokens)

▫️Composability across chains

▫️Enhanced liquidity and interoperability

▫️Early testnets with non-ZK chains are already active and preparing to join the mainnet.

What’s Next: AggLayer v0.3

The upcoming AggLayer v0.3, expected by the end of Q1, aims to make the protocol fully stack-agnostic. This will support a wider range of blockchain architectures and enable advanced use cases such as:

▫️Cross-chain swaps

▫️Multi-chain DeFi applications

▫️Seamless integrations for gaming and real-world assets

Conclusion

With the activation of pessimistic proofs, Polygon’s AggLayer strengthens its position as a foundational layer for the Ethereum-centric multichain future. By enabling secure interoperability across diverse blockchain stacks, it brings the industry one step closer to trust-minimized cross-chain communication at scale.

https://polygon.technology/blog/major-development-upgrade-for-a-multistack-future-pessimistic-proofs-live-on-agglayer-mainnet