It is suggested by a new study that Ethereum layer-2 rollups have issues pricing small transactions, risking increased costs and denial-of-service attacks.
Small transactions are being mispriced by Ethereum’s rollup networks, creating risks that range from inflated user costs to denial-of-service attacks, according to a new study from researchers at zkSecurity, Prooflab, and Imperial College London.
Posted on Sunday, the study, “Unaligned Incentives: Pricing Attacks Against Blockchain Rollups,” detailed how various rollups calculate fees, concluding that present fee mechanisms are too simplistic to balance fairness, security, and usability.
Transactions are batched and settled on layer-1 blockchains such as Ethereum to reduce costs and increase capacity by rollups. These layer-2 networks are considered central to Ethereum’s scaling roadmap, which relies on these systems to handle high volumes of transactions.
To operate, three distinct resources must be paid for by rollups. The first is computation, the cost of executing transactions in a batch. The second is data availability, the expense of posting transaction data back to a blockchain so it can be verified. The third is the gas cost for batch settlement and proof verification.
The study finds that these three costs, despite varying independently, are not accounted for separately by most rollups. Instead, they often combine them into a single formula or apply fixed rules, which can distort prices.
According to the researchers, small transfers may be improperly valued due to this design. Users making low-value payments can end up overpaying, while attackers can exploit underpriced transactions to transmit large amounts of spam at little expense.
Five prominent rollups—Polygon zkEVM, zkSync Era, Scroll, Optimism, and Arbitrum—were analyzed by the authors, revealing significant variations in fee calculation. Some networks fix charges upon submission, others wait until a batch is finalized, and some grant refunds if the final cost is below the initial estimate.
Those mechanisms may seem technical, but they create opportunities for exploitation. For example, a refund system can be abused by attackers who submit large numbers of transactions and then reclaim a portion of the fee while still consuming network resources.
Beyond user frustration, it is argued by the paper that these weaknesses create systemic risk. If mispricing allows attackers to subsidize small transactions, they can mount denial-of-service attacks that clog the network, degrade performance, or raise costs for honest users. The problem resides not in faulty code, but in economic design choices.
Study Calls for Smarter Fee Models to Strengthen Ethereum Rollups Against Spam and Inefficiencies
The importance of these issues is underscored by the study as Ethereum’s rollup ecosystem grows. With tens of billions of dollars in assets, rollups have become high-value targets.
As a form of mitigation, “multidimensional” fee mechanisms that separately price computation, data posting, and proving are advocated for by the paper. It argues that aligning fees with actual resource use would make systems more resistant to spam while giving users more predictable costs.
Tools like dynamic adjustment, partial batching, and disclosure of cost components could all help solve the problem. Some rollup teams are already experimenting with adaptive fee curves and real-time modeling, but the study notes that standards have not yet been established.
The findings are released as Ethereum advances a roadmap centered on zero-knowledge proofs and rollup-centric scaling. Zero-knowledge virtual machines, or zkVMs, promise stronger verification of transactions, but they also introduce proving costs that can spike depending on demand and available hardware. The paper states that models which do not account for that variability risk breaking down under stress.
Inconsistent fees and degraded service can be experienced by users, exchanges, and wallets. For developers and investors, the study’s message is to look beyond headline throughput or nominally low fees and examine how those fees are determined.
