Vitalik Buterin (@VitalikButerin) says the race to make zkEVMs fast enough for Ethereum is over, and that developers should now put security first. His comments followed a milestone from ZKsy
Vitalik Buterin (@VitalikButerin) says the race to make zkEVMs fast enough for Ethereum is over, and that developers should now put security first.
His comments followed a milestone from ZKsync (@zksync). Its Airbender Prime prover verified 99% of 7,200 Ethereum $ETH mainnet blocks in under 10 seconds each, running on a single NVIDIA RTX PRO 6000 Blackwell GPU. The ZKsync token is $ZK.
"At this point, I consider the battle for speed to be definitively won, and the top priority for zkEVMs should shift fully to security," Buterin said.
Crypto Briefing reported that every block in the test set was proved within 12 seconds, and that the result places Airbender at the top of the ETHproofs(.)org public leaderboard. Ethereum adds a block every 12 seconds, so proofs need to arrive inside that window to keep pace with the chain.
The figures come from ZKsync's own evaluation, according to KuCoin News, so they have not been independently confirmed in the reporting reviewed here.
The target itself is not new. In 2025, the Ethereum Foundation proposed a standard for real-time proving, and The Block reported that it includes 10-second latency for 99% of blocks, 128-bit security (with a 100-bit minimum at launch), proof sizes under 300 KiB, and hardware costing no more than $100,000 and drawing under 10 kW.
Zero-knowledge proofs let validators check a short proof that a block was executed correctly instead of re-running every transaction. Ethereum.org explains that this shift from "everyone re-executes" to "one proves, everyone verifies" could allow the gas limit to rise without raising validator hardware requirements.
That makes the correctness of the proving systems critical. According to PANews, Buterin said three things need to be formally verified: the equivalence between the arithmetization and the Ethereum specification, a strict cap on the ratio of verification cost to block gas, and the security of the proof system itself.
Formal verification means a property is mathematically proven rather than only tested. The Ethereum Foundation has already pointed in this direction. BingX News reported that its 2026 roadmap prioritizes 128-bit provable security, explicit proof-size caps and formal verification of recursion architectures.
The next developments to watch are progress on formal verification of zkEVMs against Ethereum's specification and whether other proving teams match Airbender's results on comparable hardware.
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