Major Development Upgrade for a Multistack Future: Pessimistic Proofs Live on Agglayer Mainnet

tl;dr

• Pessimistic proofs live on mainnet
• This milestone lays the groundwork for Agglayer to go multistack by ensuring safety for cross-chain interop—regardless of a chain’s underlying security model
• Next version will come with support for Agglayer to truly be stack agnostic

Today, Agglayer hit a major milestone: pessimistic proofs are live on mainnet, unlocking the key piece for Agglayer to safely support a multistack future. This means maximum flexibility for a wider variety of chains, with different security models, to unify through Agglayer.Already, chains without zero-knowledge execution proofs are on testnet, preparing to launch to mainnet, thanks to this upgrade. Before now, only chains built with Polygon CDK could safely connect.The Agglayer v0.2 release will enable two critical features:

• flexibility for Agglayer: connection for chains of different security models
• safety: provides safety for cross-chain interoperability

In short, pessimistic proofs help make Agglayer more flexible. They ensure no single chain can withdraw more than has been deposited from the unified bridge. By treating each chain suspiciously, regardless of underlying security mechanisms, the pessimistic proof creates safety for all connected chains. Let’s ground this in a practical example. A user from Chain A, without full ZK execution proofs, can send assets to a user on Chain B, swap these assets, then transfer to a gaming Chain C with different security mechanisms to buy an NFT. (Note that the infra for this kind of bridge & call transaction is under development by a number of core contributors to Agglayer. In the meantime, browse the Github docs here.) 

Check out a developer deep dive for pessimistic proofs, here.

This is just the beginning. Let’s dig into the details.

Feeling secure with pessimistic proofs

When a chain unifies through Agglayer, it joins many other chains on a single, unified bridge connected to Ethereum, which is already live on mainnet. Connected chains on the unified bridge enable users to send fungible assets between unified chains, without wrapped synthetic versions.

But as more chains unify together, the growing network requires a robust security mechanism. This leads to an important design question: How can Agglayer provide a cryptographic guarantee that cross-chain transactions are safe? What about different provers with different security models?

The industry has come up with a number of different workarounds for cross-chain safety. Some leverage networks of verifiers that act as intermediaries to ensure a transaction is valid; others use liquidity pools to dock assets and mint new ones across chains.

The pessimistic proof is different: It allows Agglayer to be as minimal and flexible as possible. 

A variety of chains will be able to safely unify through the Agglayer, thanks to the pessimistic proof. 

Here’s how it works. Agglayer generates a pessimistic proof by collecting three key pieces of information:

• Chains update correctly;
• Chains perform their internal accounting correctly—e.g. a chain doesn’t try to withdraw tokens it doesn’t have; and
• All chains have performed correct internal accounting

This is how Agglayer looks at each chain to make sure it doesn’t try to withdraw more from the bridge than has been deposited. In this way, a chain that can’t play nice with others is only a threat to itself, but not to the rest of the aggregated network. Just as importantly, the pessimistic proof model paves the way for Agglayer to become truly stack agnostic.

In the next release by end of Q1, Agglayer goes multistack

In the interest of continuing to build in public and be maximally transparent, here’s a brief roadmap of the next step:

• Scheduled to be released by the end of Q1, Agglayer v0.3 will bring full multistack capability for EVM chains to connect to and through the Agglayer.

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