Ethereum Nodes Could Accept Private Trades, But One Crucial Cost Still Exceeds The Limit

A new proposal for Ethereum’s Frames transaction design, EIP-8141, aims to offer more flexibility for privacy-focused transactions. Submitted on September 5, the change suggests that individual nodes could accept heavier privacy transactions locally, even if they exceed a shared validation allowance. However, a new benchmark report reveals that the cost of verifying these privacy proofs significantly surpasses the existing network-wide gas limit for public propagation.

Ethereum’s Gas Limit Faces Verification Challenge

Ethereum’s current EIP-8141 draft sets a cap of 100,000 gas for signature checks and initial execution during transaction validation. This limit helps manage node workload and protect against denial-of-service attacks. Yet, a September 2 benchmark from mmjahanara shows that an optimized Groth16 proof verifier, essential for privacy designs like Tornado Cash and RAILGUN, requires 190,628 gas. The cryptographic pairing check alone accounts for 181,000 gas, already well above the proposed public allowance.

The benchmark’s full model details minimums of 211,828 gas for a single-note spend and 351,828 gas for an eight-note spend. These figures combine verifier measurements with estimated overhead and a 20,000-execution-gas charge per nullifier, which prevents double-spending. The benchmark’s author recommends at least 250,000 gas for typical optimized transactions, a recommendation not yet adopted.

Proposed Flexibility Doesn’t Guarantee Network-Wide Privacy

The open change to EIP-8141, submitted by contributor AnkushinDaniil, would turn the 100,000-gas validation maximum into a common floor. This means nodes would have to propagate qualifying transactions within that floor, while more capable nodes could opt to accept more expensive ones locally. While this offers some flexibility for individual nodes, it does not guarantee that these heavier privacy transactions would travel across the broader public network.

For users, a larger gas allowance would solve one problem. However, the EIP-8250 companion draft still limits the public mempool to only one pending Frame transaction per sender. This constraint poses another challenge for privacy designs that share a single address. The practical decision facing the Ethereum community is how to balance accommodating privacy proof validation with bounding node workload. Guaranteed public access for advanced privacy features still requires the network to handle their higher proof costs.