The Hidden Cost of EVM Equivalence in zkSync Era

EVM opcodes like SLOAD, CALL, and CREATE are not ZK-friendly. Proving a single storage read requires thousands of constraints, making the EVM a computational black hole. This complexity directly translates to slower proof generation and higher costs for users.

• Exponential Constraint Growth: A simple DEX swap can generate millions of constraints.
• Hardware Bottleneck: Provers require specialized, expensive GPUs/ASICs, centralizing infrastructure.

zkSync Era bypasses the EVM at the proof layer. It compiles Solidity/Vyper down to a custom, ZK-optimized bytecode (LLVM IR -> Boojum). This creates a far simpler proving target while maintaining source-level compatibility for developers.

• Circuit-Level Optimization: Native support for Keccak, ECDSA, Storage as precompiles.
• Parallel Proving: The Boojum prover architecture enables horizontal scaling, unlike sequential EVM simulation.

The spectrum from EVM-Compatible (Polygon zkEVM) to EVM-Equivalent (Scroll) to Language-Equivalent (zkSync) defines the complexity tax. Full equivalence (proving the exact Ethereum spec) is the most expensive. zkSync's approach sacrifices byte-for-byte equivalence for radically better economics.

• Developer Win: Same Solidity tooling (Hardhat, Foundry).
• User Win: Sub-$0.01 transactions at scale vs. $0.10+ on full-equivalence chains.

Polygon zkEVM pays the full complexity tax to achieve bytecode-level equivalence. This maximizes developer portability but accepts higher proving costs, relying on aggressive hardware scaling and proof aggregation to reduce marginal cost. It's a bet that raw hardware efficiency will outpace architectural advantages.

• True Forkability: Any Ethereum tool or contract works unmodified.
• Hardware Arms Race: Depends on continuous prover optimization to stay competitive.

The proof complexity tax is ultimately paid by users via higher transaction fees or by the protocol via inflation/subsidies. For a rollup to be sustainably cheap, it must minimize this tax. Chains that ignore it will either have centralized sequencers covering the cost or will be priced out of the market by leaner competitors like zkSync.

• Sustainability: Low proof cost enables profitable sequencing at scale.
• Market Fit: High-frequency DeFi (Uniswap, Aave) will gravitate to the lowest-cost prover.

The endgame is not proving the EVM, but replacing it. zkSync's LLVM-based path points towards a future where developers write in any language (Rust, C++, Solidity) that compiles to a universal ZK-IR. The "EVM" in zkEVM will become a legacy compatibility layer, not the core runtime.

• Beyond Solidity: Native support for Move, Cairo-like languages.
• Vertical Integration: Custom VMs for specific app-types (e.g., a DEX-specific zkCircuit).

EVM Equivalence's reliance on a single, centralized sequencer for fast finality creates a single point of failure and censorship. This architecture contradicts the core value proposition of L2s.

• Centralized Control: A single entity orders all transactions, enabling MEV extraction and transaction filtering.
• Liveness Risk: Network halts if the sequencer fails, unlike decentralized L1s or L2s with multiple proposers.
• Economic Capture: All fees flow to a single entity, disincentivizing decentralization.

True security rests on decentralized, trustless proof verification. EVM Equivalence often outsources this to a small, centralized set of provers, creating a hidden trust assumption.

• Prover Centralization: A handful of entities generate validity proofs; failure creates settlement delays.
• Verifier Trust: Users must trust the canonical bridge's verifier contract, a single point of failure.
• Data Availability Reliance: Security collapses if the sequencer withholds transaction data, a risk shared with Optimistic Rollups.

EVM Equivalence simplifies porting contracts but creates fragile, centralized bridges. Cross-chain messaging via the sequencer reintroduces the very trust models L2s aim to solve.

• Bridge Centralization: Native bridges are controlled by the sequencer multisig, a $1B+ honeypot.
• LayerZero & CCIP Dependence: Projects default to external messaging layers, adding complexity and new trust assumptions.
• Settlement Fragility: Cross-rollup composability fails if the sequencer is offline or malicious.

The fix is decoupling execution from consensus and data availability. Networks like Celestia, EigenDA, and near provide the blueprint for credible neutrality.

• Shared Sequencers: Networks like Espresso and Astria decentralize transaction ordering across rollups.
• Decentralized Prover Networks: Projects like RiscZero and Succinct enable permissionless proof generation.
• Modular DA Layers: Separating data posting (e.g., to Celestia) from execution breaks the sequencer's data monopoly.

Move from transaction execution to outcome fulfillment. Protocols like UniswapX, CowSwap, and Across use solvers to compete on best execution, naturally decentralizing flow.

• Solver Competition: Users express intent (e.g., 'swap X for Y'); a decentralized network of solvers competes to fulfill it.
• Censorship Resistance: No single sequencer can block an intent, as alternative solvers can propose solutions.
• Native Cross-Chain: Intents are chain-agnostic, reducing reliance on any single L2's centralized bridge.

Accept that full EVM Equivalence is a trade-off. Validiums (zk-Rollups with external DA) offer higher scalability and decentralization by design, forcing application-specific security choices.

• DA Choice: Teams can choose Celestia, EigenDA, or even Ethereum for data availability, breaking vendor lock-in.
• Sovereign Enforcement: The chain's rules are enforced by its proof system, not a centralized sequencer.
• Prover Economics: A competitive market for proof generation emerges, as seen with StarkEx and its permissionless prover model.

zkSync Era replaces core EVM precompiles (e.g., cryptographic functions) with custom system contracts. This breaks the 'equivalence' promise and creates a fragmented dev experience.\n- Devs must rewrite logic that relies on ecrecover or sha256.\n- Audit surface expands for custom, less battle-tested contracts.\n- Porting dApps from Ethereum or other L2s like Arbitrum or Optimism is non-trivial.

zkSync's custom zkEVM uses LLVM for compilation, enabling direct circuit optimization. This is the core trade-off: sacrificing bytecode-level equivalence for superior performance.\n- Prover efficiency is higher than EVM-bytecode-interpreting ZK-EVMs (e.g., Scroll, Polygon zkEVM).\n- Long-term, this enables cheaper L1 settlement and faster finality.\n- Short-term cost: Requires a custom Solidity compiler (zksolc) and toolchain.

Era's state diff model and Boojum upgrade prioritize L1 compression, but shift costs to L2. Accessing historical state requires non-trivial storage proofs.\n- Architects must design for expensive state access patterns.\n- This impacts indexers, bridges (like LayerZero, Across), and any contract needing historical data.\n- Contrast with Optimism's Cannon fault-proof model, which has different security-cost trade-offs.

zkSync Era enforces native account abstraction (AA) at the protocol level. Every account is a smart contract wallet. This is a fundamental architectural divergence.\n- Enables sponsored transactions and batched ops (like StarkNet, but at the VM level).\n- Breaks assumptions of Externally Owned Account (EOA) based tooling and meta-transaction services.\n- Forces dApp UX to adapt, adding complexity for simple integrations.