The Billion-Dollar Bottleneck Making Your Crypto Transactions Costly

The Billion-Dollar Bottleneck Making Your Crypto Transactions Costly | Opinion

The expenses tied to crypto transactions are significantly influenced by the proof generation process involved in zero-knowledge (ZK) rollups. This bottleneck presents a major cost issue, as generating proofs can account for a large portion of transaction fees. A combination of specialized hardware and an open market for proving can help lower costs and enhance scalability in this space.

Key Takeaways

The high fees for ZK-rollup transactions are largely due to proof generation costs, not network congestion.
The current proving process requires extensive computing power, leading to significant expenses.
A centralized market for “prover farms” has emerged, creating a potential single point of failure.
To reduce transaction costs, we need both domain-specific hardware (ASICs) and a decentralized proving market.
Cheaper proving solutions could encourage widespread adoption, benefiting both users and developers.

To solve the bottleneck problem, we need a global bazaar for proofs, where anyone contributes, everyone verifies, and the open web is secure.

Unpacking Your Transaction Fees

When you attempt to bridge $50 from Ethereum to a ZK-rollup like zkSync, you're often surprised by transaction fees ranging from $0.15 to $0.50. This is frustrating, especially when you consider that optimistic rollups typically cost three times less, and the recent Dencun upgrade cut data costs by over 90%. The real issue isn't congestion; it's the generation of the proof.

Creating a zero-knowledge proof for a batch of transactions is a complex task, requiring trillions of mathematical operations—specifically elliptic curve multiplications—performed on hardware that isn’t optimized for this purpose. Data from L2Beat indicates that the proving process alone consumes a shocking 60-70% of all fees on ZK-L2s.

This situation has led to the rise of a centralized market of “prover farms,” estimated to be worth over $97 million. This highlights the billion-dollar bottleneck, where a resource-hungry centralized system relies on incompatible hardware, keeping ZK scaling more of a potential than a reality.

Understanding Where Your Fees Go

In ZK-rollups, transaction fees break down into several components. The execution within L2 is almost free. Thanks to blobs, posting data to the mainnet is quite economical, costing a fraction of a cent per transaction. However, the proving itself is the most significant expense. Generating a single proof for 4,000 transactions can take 2 to 5 minutes even on high-end GPUs, resulting in costs of $0.04 to $0.17 just in cloud computing fees. Under heavy usage, those costs can spike to over ten cents,

Zero-knowledge proving differs from the matrix math used in AI, incorporating multi-scalar multiplications (MSMs) and number-theoretic transforms (NTTs) over elliptic curves. Such operations are challenging for GPUs, which excel in parallel floating-point processing. Each Groth16 proof requires about 10¹² field operations, and tests show that 80% of GPU cycles remain idle during this process due to compatibility issues. In Q1 2025, zkSync Era reported that proving was responsible for 65% of their $2.3 million revenue—$1.5 million flowing to centralized providers.

Notably, while optimistic rollups (like Base, Arbitrum, and Optimism) also face limitations—requiring up to a week for withdrawals to allow validators to verify state transitions—they are not without trade-offs. In the fast-changing world of decentralized finance (DeFi), such delays may deter users, particularly in high-stakes financial transactions.

Overall, the key to achieving cheap, scalable, and secure transactions lies not in avoiding proof generation but in innovating how it's done.

The Centralization Challenge

A concerning trend is that over 90% of ZK-rollups depend on a small number of companies offering “prover-as-a-service.” This creates a single point of failure. For example, in March 2025, Blast operators inadvertently froze transactions from 12,000 innocent users for two days. Centralized provers can see plaintext batches, extract miner extractable value (MEV), and reject specific transactions. The structure of dYdX, using a 3-of-5 multisig arrangement, exemplifies a potential vulnerability where three insiders could seize control of the chain, echoing issues faced by other blockchain systems like Solana.

This centralization fosters fragility. Although top provers maintain 99.2% uptime, even a single outage within AWS can disrupt operations. In Q2 2025, Starknet experienced a 20% reduction in throughput due to one node's failure, while these providers capture 80% of margins, leaving rollups financially constrained. This puts Ethereum’s Layer 1 in a paradoxical situation where “decentralized” Layer 2 solutions still rely heavily on centralized Web2 infrastructures. As Vitalik Buterin said during Devcon 2024, relying on outsourced proof generation effectively means no true scalability has been achieved.

Path to a Solution

To tackle these challenges, we need a dual approach: specialized hardware designed for ZK proofs and a marketplace that enables efficient distribution of these resources. Current GPU technology is more suited to AI tensor calculations than the elliptic curve operations needed for zero-knowledge proofs. This is where domain-specific application-specific integrated circuits (ASICs) come into play.

The winners of the 2025 ZPrize competition demonstrated that STARK proofs could be completed in 6-8 seconds on FPGAs—10-100 times more efficient than GPUs. Companies like Cysic are developing ASICs capable of generating proofs for complex circuits in under two seconds, drastically cutting energy usage by 50 times. This evolution parallels the transition from CPUs to ASICs seen in Bitcoin mining, but here, the focus is on truth instead of hashing.

Secondly, we need to revolutionize how provers operate, moving away from the Software as a Service (SaaS) model, to treating proving as a commodity. A good example is Succinct's 2025 mainnet, where rollups can post jobs for auction on the Ethereum blockchain, allowing specialized rigs to place competitive bids quickly. Brevis ProverNet has managed to enhance CPU efficiency using GPU clusters and implementing penalties for slow nodes, resulting in cost reductions of 40%, fairer value distribution, and resistance to censorship. This means anyone can provide proofs, while Ethereum takes on the responsibility of verification. The recursive aggregation technology showcased at the 2025 ZPrize enabled on-chain proof verification in under 200 milliseconds.

Opening the Floodgates

As the cost of proving decreases, transaction fees could drop predictably to under $0.01, even at 15,000 transactions per second, according to zkSync's Atlas roadmap. This will allow for innovations like pay-per-pixel NFTs, dynamic gaming economies, and AI agents executing trades without risk. ZK rollups can evolve into neutral infrastructure platforms rather than controlled prover systems.

Developers will prioritize optimizations for virtual machines rather than dealing with cumbersome server management, igniting a surge of application innovations, causing ZK total value locked (TVL) to grow from $28 billion in 2025 to over $100 billion. The true opportunity here is systemic.

When proving becomes both cost-effective and decentralized, the entire value proposition strengthens—users enjoy faster and cheaper transactions, developers gain a platform that doesn't necessitate trust in a few operators, and Ethereum finds a scaling pathway that safeguards its security without compromise.

The Battle Continues

Ultimately, the primary barrier to adopting ZK technology resides in engineering economics, with centralized infrastructure currently hindering scalable truth. The ongoing conflict isn't centered around consensus but rather within the realm of hardware and markets for verifiable computation. By deploying decentralized, accelerated proving systems, we can achieve inexpensive, trustless transactions for millions of users.

What we really need is not a handful of “prover overlords,” but a collective marketplace for proofs, enabling universal contribution, verification, and ultimately a more secure open web.