Ethereum developers are working toward a quantum-resistant Layer 1 network transition by the end of 2029. The upgrade plan includes an intermediate step beginning at the end of 2026, when account signatures will transition to stronger cryptographic methods that can withstand quantum computing threats.
The transition will proceed in phases without requiring the entire network to switch simultaneously. Later upgrades will extend quantum-resistant protections to validators, network data, and rollups. Completing the full transition requires five upgrades after Glamsterdam, with approximately seven months scheduled between each upgrade. Testing will be critical, with more than ten client teams already running weekly trials.
Managing Signature Size Growth
A significant technical challenge involves signature size. Validators currently use compact 96-byte BLS signatures, which are aggregated into single compact signatures. Quantum-resistant leanXMSS signatures will provide similar security against quantum attacks but will grow to approximately 3100 bytes in size.
To address this scaling concern, leanVM is being developed to reduce quantum-resistant signatures by approximately 250 times their initial size. Rather than forcing a single network-wide change, EIP-8141 allows individual accounts to independently choose when to adopt safer signature options.
Finality and Execution Improvements
Ethereum is also targeting improvements to transaction finality, which currently takes roughly 13 to 16 minutes. New designs aim to gradually reduce this delay toward seconds, enabling faster settlement without requiring disruptive network-wide changes. Progress on zkEVM infrastructure demonstrates that execution improvements are already advancing toward these goals.
January 2027 will provide an early test of whether Ethereum can maintain its upgrade schedule and remain on track for the 2029 target. The protocol has a backup plan in place if quantum computing advances arrive earlier than anticipated.
