ZK-Rollup Censorship Resistance Depends on Prover Decentralization

A centralized prover is a censor. It can selectively ignore transactions, creating a permissioned layer-2. The sequencer-prover collusion risk is systemic.

• Key Risk: Prover can blacklist any address or transaction type.
• Key Metric: ~0% censorship resistance if prover is centralized.

Proving is expensive. Centralized provers create a high fixed-cost moat, discouraging competition and enabling rent extraction. This leads to L2 MEV and high, opaque fees.

• Key Risk: Economic centralization begets technical centralization.
• Key Metric: $1M+ hardware setup costs create barriers.

Not all decentralization is equal. Compare models: Permissioned Sets (Starknet, zkSync), Permissionless PoS (Polygon zkEVM), and emerging Proof Markets (RiscZero, Gevulot).

• Key Insight: Permissioned sets are a start, but proof markets are the endgame.
• Key Entity: RiscZero's Bonsai network enables verifiable compute-as-a-service.

Decentralized proving is useless without decentralized verification. A single verifier contract on L1 can be corrupted or upgraded maliciously. True security requires multiple, economically bonded verifiers.

• Key Risk: L1 governance attack can compromise all L2 state.
• Key Solution: Multi-verifier systems or EigenLayer-style restaking for verification.

Decentralization adds latency. A proof market must aggregate work and reach consensus, adding ~minutes to proof generation time versus a centralized prover's ~seconds.

• Key Trade-off: Censorship resistance vs. finality speed.
• Key Metric: ~10-100x latency increase for decentralized proving.

The solution is to treat proof generation as a commodity. Standardized proof systems (e.g., RISC-V for ZK, like RiscZero) and open proving markets break monopolies. This mirrors the evolution from solo miners to mining pools.

• Key Entity: Gevulot is building a decentralized network for proof generation.
• End State: Provers compete on cost and speed, not control.

Most rollups run a bundled sequencer and prover, creating a centralized choke point. This entity can censor transactions or halt the chain by withholding proofs.\n- Single point of failure for liveness and censorship resistance.\n- Creates trust dependency contrary to ZK's trust-minimizing promise.\n- Bottlenecks proof generation speed and cost innovation.

Decouple proof generation from sequencing. Allow any node with a GPU to compete to generate proofs for posted batches, modeled after Ethereum's validator or Bitcoin's miner marketplace.\n- Economic security via staking/slashing for provers.\n- Censorship resistance via multiple proof producers.\n- Cost efficiency through competitive bidding (see Espresso Systems, RiscZero).

Implement a marketplace where sequencers auction proof-generation jobs. Provers bid based on cost and latency. Advanced systems use proof aggregation (e.g., Nil Foundation) to batch proofs for efficiency.\n- Market-driven pricing for computational work.\n- Redundancy: Multiple provers can work on the same batch.\n- Specialization: Provers optimize for specific circuits (zkEVMs vs. zkWASM).

Proof generation is GPU/ASIC-heavy, risking a shift from validator centralization to hardware oligopoly. Without careful design, the prover market could be controlled by a few large farms.\n- Capital barriers for high-end hardware create centralization.\n- Algorithm agility is needed to resist ASIC dominance.\n- Requires proof-of-stake slashing layered on top of proof-of-work.

The most robust design uses Ethereum L1 as a neutral auction platform. Sequencers post batch data and a bounty; L1 smart contract assigns the proof task. This mirrors MEV-boost architecture but for verification.\n- L1-guaranteed neutrality and censorship resistance.\n- Universal access for provers via public mempool.\n- Enables restaking of ETH (e.g., EigenLayer AVS) for prover security.

Measure censorship resistance by the time a malicious sequencer can delay a transaction. With N decentralized provers, TtC depends on the fastest honest prover. This creates a liveness race similar to blockchain consensus.\n- Quantifiable security for users and regulators.\n- Incentivizes prover geographic/distributor decentralization.\n- Key metric for sovereign rollups and appchains.