Direct verification is infeasible. A single ZK-VM proof for a complex transaction can be hundreds of kilobytes, costing more in L1 gas than the transaction itself. This defeats the purpose of scaling.
zk-rollups-the-endgame-for-scaling
Blog
Why Zero-Knowledge Virtual Machines Rely on Aggregation to Scale
ZK-VMs promise a scalable, EVM-compatible future, but their raw proofs are too slow and costly. Proof recursion and aggregation—used by zkSync's Boojum and Polygon zkEVM—are the non-negotiable engineering solutions that make continuous block production economically viable.
introduction
THE BOTTLENECK
The ZK-VM Paradox: Too Powerful to Be Practical
Zero-knowledge virtual machines generate proofs too large and slow for direct on-chain verification, forcing a reliance on aggregation.
Aggregation is the only path. Systems like zkSync's Boojum and Polygon zkEVM use recursive proof systems to bundle thousands of proofs into one. This single proof verifies the entire batch on-chain.
The trade-off is latency. Aggregation introduces a delay as proofs are collected and recursively composed. This creates a fundamental tension between finality speed and cost efficiency.
Evidence: StarkNet's SHARP prover aggregates Cairo programs, reducing the cost per transaction by orders of magnitude, but finality is not instantaneous.
key-trends
WHY ZK-VMS NEED AGGREGATION
The Scaling Bottleneck: Proof Generation
Generating a single ZK proof for a large block is computationally prohibitive, creating a fundamental limit to throughput.
01
The Single-Proof Bottleneck
A ZK-VM like zkSync Era or Polygon zkEVM must prove the execution of an entire block. Proving time scales super-linearly with computation, creating a hard cap on TPS.\n- Proof Time: Can take minutes for a single, full block proof.\n- Sequencer Stalling: The network must wait for this proof before finality, creating high latency.
~3-10 min
Proof Time
~10-100 TPS
Base Throughput
02
Recursive Proof Aggregation
The solution is to prove proofs. Projects like Nil Foundation and Succinct Labs build infrastructure to aggregate many small proofs into one. This uses recursive SNARKs (e.g., Plonky2, Halo2).\n- Parallel Proving: Many provers work on small chunks simultaneously.\n- Single Final Proof: A root proof verifies all aggregated proofs, submitted to L1.
1000x+
Proving Capacity
~20 sec
Finality Target
03
The Prover Marketplace
Aggregation enables decentralized proving networks. Espresso Systems and Georli are building markets where specialized hardware (GPUs, ASICs) competes to generate proofs cheapest and fastest.\n- Cost Reduction: Competition drives proving costs toward marginal electricity.\n- Censorship Resistance: No single entity controls proof generation.
-90%
Cost Target
Decentralized
Prover Set
04
The Data Availability Layer
Aggregated proofs are useless without the data to verify them. This creates a symbiotic scaling loop with EigenDA, Celestia, or Avail. The DA layer provides cheap data, the ZK-VM provides validity.\n- Cost Scaling: DA cost decouples from Ethereum gas fees.\n- Modular Stack: Enables specialized, high-throughput ZK-rollup chains.
$0.01-0.10
DA Cost/Tx
10k+ TPS
Theoretical Max
ZKVM AGGREGATION LAYERS
The Cost of Truth: Proof Generation Benchmarks
Comparing the economic and performance trade-offs of leading ZKVM proof aggregation strategies. Data is based on public benchmarks and testnet performance.
| Core Metric | Direct On-Chain Verification (Baseline) | Proof Aggregation (e.g., zkSync Era, StarkNet) | Recursive Proof Aggregation (e.g., Polygon zkEVM, Scroll) |
|---|---|---|---|
On-Chain Verification Gas Cost | ~1.5M - 5M gas | ~500k - 800k gas | ~200k - 400k gas |
Prover Time per Tx (Client Hardware) |
| 5 - 15 seconds | 15 - 30 seconds |
Requires Trusted Setup | |||
Supports Native EVM Opcodes | |||
Prover Hardware Cost (Approx.) | $50k+ (High-End GPU/ASIC) | $5k - $15k (Consumer GPU) | $10k - $25k (Optimized CPU/GPU) |
L1 Finality After Proof (Target) | ~20 minutes | ~10 minutes | < 5 minutes |
Recursive Proof Depth | N/A | 1 (Single Batch) | Unbounded (Nested Proofs) |
deep-dive
THE ECONOMICS
How Recursion Turns a Cost Center into a Profit Engine
Recursive proof aggregation transforms the high cost of ZK verification into a scalable, profitable business model for VM execution.
Recursion flips the unit economics. A single ZK proof for a virtual machine like zkEVM costs thousands of dollars in compute. Recursive aggregation bundles thousands of proofs into one, amortizing that fixed cost across all transactions.
The profit engine is aggregation-as-a-service. Protocols like Polygon zkEVM and zkSync Era rely on centralized provers today. The market will shift to decentralized prover networks like Risc Zero and Succinct, where aggregators compete on cost and speed.
This creates a new financial primitive. Aggregators earn fees for proving, while users pay near-zero verification costs. The model mirrors AWS for computation, but with cryptographic guarantees instead of trust.
Evidence: A Risc Zero benchmark shows verifying a single proof costs ~$0.001, while generating it costs ~$0.20. Aggregation reduces the effective cost per transaction to fractions of a cent, enabling micro-transactions at scale.
protocol-spotlight
ZKVM SCALING MECHANICS
Aggregation in the Wild: Protocol Implementations
ZKVM proofs are computationally intensive; aggregation is the non-negotiable compression layer that makes them economically viable.
01
The Recursive Proof Bottleneck
A single ZKVM proof for a complex transaction can take minutes and cost $10+ to generate. Sequentially proving a block of transactions is impossible for real-time L2s.
- Problem: High latency and cost per proof kills UX and throughput.
- Solution: Parallel proof generation with a final aggregation step, compressing hundreds of proofs into one.
10-100x
Proofs/Batch
-90%
Cost/Proof
02
zkSync Era's Boojum & zkPorter
zkSync's custom STARK-based proof system, Boojum, is designed for aggregation from the ground up. It feeds into a recursive SNARK for final L1 verification.
- Aggregation Layer: Provers generate many proofs off-chain, aggregated into a single proof for Ethereum.
- Economic Impact: Enables ~2000 TPS target while keeping L1 settlement costs manageable.
~2000
Target TPS
1
L1 Proof/Block
03
StarkNet's SHARP & Proof Market
SHARP (Shared Prover) is the canonical aggregator for StarkNet and other StarkEx apps (dYdX, Sorare). It batches proofs from multiple sources.
- Market Dynamics: Creates economies of scale; any app can pay to join the batch.
- Efficiency: Aggregates millions of transactions into a single Cairo STARK proof, amortizing cost across the entire ecosystem.
Millions
Txs/Batch
Cents
Cost/Tx
04
Polygon zkEVM's Aggregation Service
Uses a modular prover network where specialized nodes generate proofs for batches, which are then aggregated. The architecture separates execution, proving, and aggregation.
- Key Design: Aggregation-as-a-service model allows for prover decentralization and redundancy.
- Result: Reduces final verification cost on Ethereum to a fixed ~200k gas, independent of batch size.
~200k
Fixed L1 Gas
Modular
Prover Network
05
Scroll's Rollup & Roller Networks
Scroll's zkEVM uses a decentralized prover network called "Rollers". Their aggregation strategy uses a multi-layer proof system (GPU for execution, Groth16 for final aggregation).
- Process: Many layer-2 block proofs are aggregated into a single layer-1 validity proof.
- Goal: Decentralize the proving process while maintaining efficient final aggregation to Ethereum.
Decentralized
Prover Nodes
2-Layer
Proof Stack
06
The Economic Imperative
Without aggregation, ZK-Rollups are a non-starter. The cost to verify on L1 must be less than the value secured.
- First-Principle: Aggregation transforms a variable cost (O(n)) into a near-fixed cost (O(1)) for the base layer.
- Endgame: Enables ZK-Proofs-as-a-Service (ZKaaS) and viable micro-transactions, unlocking new use cases.
O(1)
L1 Cost
ZKaaS
Emerging Market
counter-argument
THE AGGREGATION IMPERATIVE
The Trade-Offs: Trust, Latency, and Centralization Pressure
ZKVM scaling necessitates aggregation, a process that introduces fundamental compromises in trust assumptions, finality speed, and network architecture.
Aggregation trades latency for cost. A single ZK proof for a block is slow and expensive. Aggregators like Risc Zero or Succinct batch multiple proofs into one, amortizing cost but adding a waiting period for batch finalization.
Trust shifts from validators to provers. The security model pivots. You now trust the ZK prover network (e.g., Espresso Systems sequencers) to correctly aggregate, not just the L1 to verify. This creates a new, specialized trust layer.
Centralization pressure is inherent. Proof generation is computationally intensive, favoring specialized hardware (ASICs, GPUs). This creates economies of scale that lead to prover centralization, mirroring the miner centralization in early PoW.
Evidence: Polygon zkEVM's prover time for a large batch is ~10 minutes, but cost per transaction falls by ~99%. This latency-cost tradeoff defines the user experience for ZK-rollups.
FREQUENTLY ASKED QUESTIONS
ZK-VM Aggregation: Critical Questions
Common questions about why Zero-Knowledge Virtual Machines rely on aggregation to scale.
ZK-VMs need aggregation to amortize the high cost of proof generation and verification. A single ZK proof for a large block is computationally prohibitive. Aggregation, as used by zkSync Era and Polygon zkEVM, allows many smaller proofs to be combined into one, drastically reducing the on-chain verification cost per transaction.
takeaways
ZKVM SCALING PRIMITIVE
The Verdict: Aggregation is the Foundation
Zero-Knowledge Virtual Machines (zkVMs) like zkSync, Scroll, and Polygon zkEVM cannot scale by simply proving single transactions; they require aggregating thousands of proofs into one.
01
The Problem: Exponential Proving Overhead
Generating a ZK proof for a single EVM opcode is computationally heavy. Proving an entire block of transactions individually would be prohibitively slow and expensive, creating a fundamental bottleneck for throughput.
1000x
Slower Than Execution
$10+
Cost Per Tx (Without Agg)
02
The Solution: Recursive Proof Aggregation
zkVMs use recursive SNARKs/STARKs to bundle thousands of individual transaction proofs into a single, succinct proof. This aggregated proof is what gets verified on-chain, amortizing cost across the entire batch.
- Enables ~2000 TPS per zkVM block
- Reduces on-chain verification cost to ~$0.01 per transaction
~2000
TPS Potential
-99%
Cost Per Tx
03
The Infrastructure: Aggregation Layers (zkEVM, zkSync)
Protocols like zkSync Era and Polygon zkEVM are, at their core, specialized aggregation engines. Their sequencers batch transactions, generate proofs, and rely on shared prover networks (e.g., Espresso, RiscZero) for decentralized proving power.
- Decouples execution from proving for horizontal scale
- Enables validity proofs for general-purpose smart contracts
10-100x
Throughput vs L1
~5 min
Finality Time
04
The Trade-off: Latency for Throughput
Aggregation introduces inherent latency. Waiting to fill a batch and generating the recursive proof takes minutes, unlike instant L1 confirmation. This is the core scalability trilemma for zkVMs: decentralization, scalability, and low latency—pick two.
- Optimistic Rollups (Arbitrum, Optimism) choose low latency
- zkRollups choose maximal scalability and security
~10 min
Avg. Finality
1-2 sec
Soft Confirmation
05
The Next Frontier: Aggregation of Aggregations
The logical endpoint is proof aggregation across multiple zkVM chains. Projects like Polygon AggLayer and Avail are building infrastructure to unify liquidity and state across sovereign zk-chains with a single proof, creating a unified ZK ecosystem.
- Solves fragmentation without centralization
- Enables atomic cross-rollup composability
Unified
Liquidity Layer
1-Proof
For N Chains
06
The Economic Model: Prover Markets & Sequencing
Aggregation creates new markets. Decentralized prover networks (e.g., Gevulot) compete to produce the cheapest/fastest proofs. Shared sequencers (Espresso, Astria) decouple ordering from proving. This separates the execution layer, proving layer, and settlement layer for optimal efficiency.
Auction-Based
Prover Pricing
~$0.001
Target Cost/Tx
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