Original by Delphi Digital

Original compilation: Luffy, Foresight News

Modular theory is generally considered to consist of four layers: DA (Data Availability), Consensus, Execution, and Settlement. However, a new layer, the shared prover, may be integrated into the modular theory.

Could it be the missing piece of efficient, scalable validation? The shared prover, proof aggregation, and prover markets are changing the landscape of zk-SNARKs. You can learn everything you need to know in our latest report.

Below is a summary 👇 of the key takeaways from the report

Brief review of zk Rollup

The zk Rollup solution can scale Ethereum's transaction size, moving transactions off-chain for faster processing, while enabling hard determinism on top of Ethereum and verifying with zk proofs (zk-SNARKs).

zk proof: fast verification, slow generation

While zk proofs are powerful in terms of privacy and scaling, creating proofs on Ethereum can be costly and slow.

The high cost of attestation limits zk apps. New approaches such as attestation aggregation and prover marketplaces aim to address these limitations.

Protender Supply Chain

Shared sequencers provide high throughput for transactions across Blockchain. However, they don't actually prove anything. They may be integrated with a shared prover network in the future to delegate this task.

Today, rollups face the challenge of expensive, separate zk-SNARKs submissions.

The Proof Network provides a solution: a unified marketplace where various ZK applications can outsource proof generation to dedicated attestation service providers, increasing costs and efficiency.

Shared attestators can greatly improve the situation for applications that require zk-proof support but lack in-house zkVM or circuit development resources.

Currently, Rollups submit separate zk proofs, resulting in high gas costs during peak hours.

The goal of the prover network now is to outsource the generation of proofs to specialized hardware providers in order to increase efficiency.

In a network with longest rollups and connected to a prover network, the transaction lifecycle works as follows:

• Rollup submits an attestation request.
• The matching mechanism selects a prover.
• The certifier satisfies the request.
• Aggregate proofs.
• The prover submits the final attestation to L1 for verification.

Allocate the cost of validation

Proof Singularity refers to a variety of techniques designed to drop on-chain proof of validation costs.

Proof aggregation is one of these techniques, which compresses longest valid proofs into a single proof that verifies all proofs.

This "batch validation" can drop gas costs compared to verifying each proof individually.

zk App Prover Cost

The high verification cost and proof time of ZK applications is ultimately passed on to the user.

Over the past few years, zk applications (mostly Rollups) have spent nearly $30 million in gas to validate and publish proofs on the on-chain.

Proof aggregation protocol profile

Nebra UPA

Nebra UPA lets zk apps bundle long proofs to drop the cost of verification, and they claim to support about 10 proofs per second on Testnet. Their certifiers are currently centralized, but plan to implement them later without the need for proof of permission.

They have a forced inclusion mechanism similar to the existing L2 escape pods. If the prover reviews or latency the proof, the zk application can bypass the prover and enforce the proof settlement on L1.

Aligned Layer

Aligned Layer is Ethereum's universal zk verification layer secured by EigenLayer AVS. Restakers provides users with soft finality through proof aggregation and single Ethereum commits. The default DA is EigenDA, but you can also choose other DA layers, such as Celestia or Avail.

AggLayer

Polygon's AggLayer is a neutral infrastructure for secure cross-chain interoperativity. It aims to unify independent Blockchain networks under a single cross-chain bridge, facilitating interoperability without compromising Blockchain sovereignty.

The system is designed to aggregate the proofs in all connected rollups and then submit a unique proof that contains the Merkle tree for each individual proof submitted.

• It does not require a specific Virtual Machine or execution environment
• Blockchain is free to choose its own gas Token
• It does not need to be subject to co-governance.

Under the hood, the infrastructure that brings all of this together is the LxLy cross-chain bridges, which standardizes a common cross-chain messaging protocol so that Rollups can communicate with each other and with Ethereum while maintaining sovereignty.

A brief explanation 👇 of how LxLy works

• Each chain tracks withdrawal transfers in a Merkle tree (exit tree).
• All exit trees are merged into a global exit tree, which is shared cross-chain
• Updated local and global trees to allow validation and net withdrawal calculations.

In addition, Agglayer has a shared cross-chain bridge between connected rollups, simplifying the flow of assets between L1 and L2. Assets are collateralized in an L1 contract without wrapping or locking/minting.

Traditionally, frameworks have relied on a single internal prover, risking censorship and liveness issues. A network of provers may start in a centralized manner and gradually Decentralization over time.

Decentralization of the prover market is still an open question, but some approaches are being explored:

• Proof Competition: The fastest prover wins, improving efficiency but wasting computation (costs passed on to users).
• Proof Mining: Similar to PoW Mining, random numbers are used to prevent winner-take-all (computational waste still exists). Hardware acceleration in SNARK ASICs is expected to drop costs.