ZK-Rollup Interoperability Will Be Decided by a Proving System War

Proving systems dictate interoperability. The choice between SNARKs (e.g., Groth16, Plonk) and STARKs determines latency, cost, and compatibility, creating distinct, non-fungible ecosystems. A ZK-Rollup built on a Plonk-based system like Polygon zkEVM cannot natively verify a Starknet proof without a costly, trust-minimized bridge.

The battle is for the universal verifier. Projects like Ethereum's EIP-7212 and RISC Zero aim to standardize verification, while zkSync's Boojum and StarkWare's Stwo optimize for proprietary performance. The winning system will be the one that balances succinctness, recursion speed, and developer ergonomics for cross-chain state proofs.

Evidence: Starknet's SHARP prover aggregates thousands of Cairo transactions into a single STARK proof for Ethereum, but this model is incompatible with the SNARK-based proof aggregation used by zkSync Era or Linea. This fragmentation is the core technical barrier to a unified ZK-Rollup layer.

Proving systems are the base layer. The ZK-Rollup's state transition function is irrelevant if its proof cannot be verified cheaply and universally. The proving system defines the cost, speed, and trust model for all cross-chain communication.

Interoperability is a proving system feature. A rollup using RISC Zero's zkVM can natively verify a proof from another RISC Zero chain. This creates natural interoperability clusters that bypass generic bridges like LayerZero or Axelar.

The war is between general-purpose and specialized provers. StarkWare's CairoVM and RISC Zero target general computation, while Polygon zkEVM and zkSync focus on EVM equivalence. The winner will be the system that optimizes for prover cost and verifier simplicity.

Evidence: StarkEx's shared prover for dYdX and Sorare demonstrates the economic moat of a unified proving backend. This model reduces costs and creates a locked-in ecosystem of sovereign chains.

Proving systems are the new VMs. The EVM is a consensus layer; a proving system is the execution layer for trust. The choice between STARKs, SNARKs, and hybrids like Plonky2 dictates security assumptions, cost curves, and hardware requirements for every cross-chain message.

Interoperability is a proving workload. A ZK bridge like Succinct, Polyhedra, or Herodotus does not move assets; it generates a proof of state on another chain. The proving system's efficiency determines finality speed and cost, making it the core competitive moat.

This creates protocol lock-in. A rollup built on RISC Zero's zkVM cannot natively verify a proof from a Polygon zkEVM using Plonky2 without a costly proof translation layer. Interoperability stacks will coalesce around dominant proving backends, creating technical silos.

Evidence: StarkWare's SHARP prover batches proofs for hundreds of apps, but only for Cairo-based chains. The war is not about bridges, but which proving standard—be it Circom, Halo2, or Boojum—becomes the TCP/IP of verified state.

Bridges and aggregators are the pragmatic solution. They operate on the principle of liquidity unification, not protocol unification. Protocols like Across, Stargate, and LayerZero create asset corridors that abstract away the underlying rollup's proving system.

Intent-based architectures bypass the problem. Frameworks like UniswapX and CowSwap separate user intent from execution. A solver, not the user, determines the optimal path across disparate rollups, making the proving system irrelevant to the end-user experience.

This creates a market for interoperability. Competing bridges and solvers optimize for cost and speed across different rollup pairs. This competitive pressure drives efficiency faster than a top-down standard ever could, as seen in the rapid evolution of Across's optimistic verification.

The evidence is in TVL and volume. Billions in value flow daily through these systems. The existence of EigenLayer AVS for bridging and Chainlink's CCIP demonstrates that the market bets on heterogeneous, application-layer interoperability over a monolithic L1-like standard.

The proving system is the moat. A ZK-rollup's security, finality speed, and cost are direct functions of its underlying proof system (e.g., Plonk, STARKs, Groth16). This creates a hard technical lock-in for developers choosing a stack like Starknet, zkSync, or Polygon zkEVM.

Interoperability becomes a feature of the prover. Cross-rollup communication will be a native function of shared proving systems, not an aftermarket bridge product. A rollup on a StarkEx prover will trustlessly sync with another StarkEx chain via recursive proofs, bypassing Across and LayerZero for core state transitions.

The market will consolidate around 2-3 systems. The extreme R&D cost and hardware optimization (GPUs, ASICs) for proving systems creates massive economies of scale. We will see a proving system oligopoly, similar to cloud providers AWS/Azure/GCP, where interop is free within a provider but expensive across them.

Evidence: StarkWare's shared prover for multiple dYdX chains is the blueprint. This architecture proves separate chains with a single proof, making their interoperability a cryptographic primitive, not a bridged connection. The war is for which proving standard becomes the TCP/IP of sovereign ZK chains.