Lean Ethereum

Lean Consensus R&D Progress

January 2026

Lean Ethereum

Lean Consensus R&D Progress

Track Lean Consensus research & engineering progress across all workstreams

Last updated: January 2026

Overview

Key Ideas

Lean Consensus: A complete redesign of Ethereum's consensus layer — hardened for security, decentralization, and finality in seconds
Lean Cryptography: Hash-based signatures ready for both SNARKs and quantum computers — one simple building block powering everything
Lean Governance: Batched upgrades instead of endless small changes — paying down 10 years of technical debt in one go
Lean Craft: Minimalism, modularity, and formal verification — when we can go the extra mile, we do

leanSpec

Specifications for the Lean Consensus work

leanSig

Post-quantum signature scheme reference implementation

leanMultisig

Post-quantum signature aggregation scheme reference implementation

leanMetrics

Specifications for Lean Consensus metrics

PQ Interop Breakout Meetings

Re-watch the weekly breakout discussions

Eth R&D Discord

Join the #post-quantum channel

@leanEthereum

Follow for updates on X

Timeline

2024

2025

2026

2027

2028

2029

2030

Now

Pilling

Speccing

Building

Testing

Benchmarks

leanSig

Hash-based signature scheme

Signature Signing & Verification Time

Public key size8 elements for root; 5 for randomiser

0bytes

Signature sizeCompact for hash-based sigs

0KiB

Key generation time10-core MacBook Pro M1; 8 years key lifetime

0hours

Signing time (Target)Performance goal

0μs

Signing timeSingle core performance, MacBook Pro M1

~0μs

107% of target

Verification time (Target)Performance goal

0μs

Verification timeSingle core performance, MacBook Pro M1

~0μs

39% of target 🎉

leanMultisig

Aggregate signature scheme

XMSS Aggregated / Second

XMSS aggregated (Target)Performance goal

0XMSS/s

XMSS aggregated (M4 Max - Efficient)main branch; optimized for prover efficiency

~0/sec

97% of target

XMSS aggregated (M4 Max - Simple)lean-vm-simple branch; optimized for simplicity

~0/sec

82% of target

XMSS aggregated (i9-12900H)Baseline Intel performance

~0/sec

38% of target

Aggregate size (Target)Performance goal

~0KiB

Aggregate size (Efficient)main branch; optimized for prover efficiency

~0 - 0KiB

313 - 391% of target

Aggregate size (Simple)lean-vm-simple branch; optimized for simplicity

~0KiB

234% of target

Devnets

pq-devnet-0

Completed: Oct 25

Completed

Goals

•Create leanSpec framework
•Multi-client coordination (no PQ sigs yet)
•Interop trials with 4s slots, QUIC, Gossipsub v1.0
•Apply modified 3SF-mini as consensus mechanism

Results

Initial client specs established
Ream, Zeam, Qlean clients interop achieved with modified 3SF-mini consensus

Clients

ReamZeamQlean

High-level specification Recap by ReamLabs

pq-devnet-1

Completed: Dec 25

Completed

Goals

•Integrate leanSig signing & verification
•Apply basic signature aggregation (by concatenation)
•Set baseline performance metrics for PQ signature signing & verification

Results

leanSig signing & verification integrated in clients
Client interop with PQ signing & verification achieved

Clients

ReamZeamQleanLanternLighthouse

High-level specification

pq-devnet-2

Target: Jan 26

Active

Goals

•Integrate leanMultisig aggregation
•Set baseline performance metrics for PQ signature aggregation

Results

In progress...

Clients

ReamZeamQleanLanternLighthouse

High-level specification

Research Tracks

Show inactive

Poseidon Cryptanalysis Initiative

Progress50%

Comprehensively tests the security of the Poseidon hash function through a multi-faceted approach including competitive bounties, targeted research grants, specialized workshops, academic awards, and advanced hardware testing.

Key Milestones

Bounties established ($66k already earned)

Jan 2025

Research grants (three recipients chosen)

Feb 2025

Workshop on Cryptanalysis of Algebraic Hash Functions at 31st Fast Software Encryption Conference

Mar 2025

Workshop at Algebraic Hash Cryptanalysis Days

May 2025

Groebner basis exploratorations

Resources

EF's Poseidon Cryptanalysis Initiativewebsite Poseidon2: A Faster Version of the Poseidon Hash FunctionMar 2023paper Attacking Poseidon via Graeffe-Based Root-Finding over NTT-Friendly FieldsMay 2025paper Breaking Poseidon Challenges with Graeffe Transforms and Complexity Analysis by FFT Lower BoundsMay 2025paper Poseidon and Neptune: Gröbner Basis Cryptanalysis Exploiting Subspace TrailsMay 2025paper

Lead:Dmitry Khovratovich

Post-Quantum SignaturesSecurity

Hash-Based Multi-Signatures

Progress70%

Develop and analyze hash-based multi-signatures using Winternitz XMSS as a post-quantum replacement for BLS signatures.

Key Milestones

Paper publication (including proofs) and prototype implementation

Jan 2025

Efficiency analysis of hash-based signature candidates

Mar 2025

Exploring further optimizations for hash-based signature candidates

Identification of alternatives for post-quantum multi-signatures

Fixing parameters such as key lifetime

Resources

Hash-Based Multi-Signatures for Post-Quantum EthereumJan 2025paper Towards Hash-Based Multi-Signatures for Post-Quantum Distributed ValidatorsMar 2025paper Follow-up research on Hash-Based Multi-Signatures (Top of the hypercube)May 2025paper Reference implementation in Rust (old)code Reference implementation in Rust (actively maintained)code Aborting Random Oracles: How to Build them, How to Use themJan 2026paper

Lead:Benedikt Wagner

Post-Quantum SignaturesSecurity

Post-Quantum Signature Aggregation with zkVMs

Progress50%

Explore minimal zero-knowledge virtual machines (zkVMs) specifically optimized for signature aggregation, including various options like Binus M3, SP1, KRU, STU, Jolt, and OpenVM.

Key Milestones

Benchmark hash in SNARK (Plonky3, STwo, Binius, Hashcaster)

Feb 2025

Hashcaster exploration work

Feb 2025

Snarkify hash-based signature aggregation with SP1 & OpenVM

Feb 2025

Explore GKR style provers

Explore WHIR

More explorations over binary field techniques

Resources

Benchmark Hash in SNARKwebsite Hash-based Signature Aggregationwebsite WHIRSep 2024paper Circuit gadgetsFeb 2025website Post Quantum Signature Aggregation: a Folding ApproachDec 2025article

Lead:Thomas Coratger

Post-Quantum Signatures

Formal Verification

Progress40%

Mathematically prove the security properties of cryptographic proof systems like FRI, STU, and WHIR using the Lean 4 framework, creating structured blueprints that map out theorem dependencies to verify that the zkEVM implementations are correct.

Key Milestones

zkEVM formal verification project initiation

Jan 2025

Lean 4 framework implementation

Mar 2025

FRI proof system specification

STIR proof system specification

WHIR proof system specification

Resources

EF's zkEVM Formal Verification Projectwebsite Formally Verified SNARKs in Leancode Lean blueprintscode ArkLib Lean blueprintwebsite

Lead:Alex Hicks

Security

P2P Networking

Progress30%

Modernizes how Ethereum consensus nodes communicate by developing next-generation networking protocols like Gossipsub v2.0 and advanced set reconciliation to enable Lean Consensus's 4-second block times and increased validators from reduced staking requirements (32 ETH to 1 ETH), and while uncompromising on decentralization.

Key Milestones

Practical Rateless Set Reconciliation research

Feb 2024

Generalized Gossipsub specification

Gossipsub V2 specification

Grid Topology research

libp2p in C development

libp2p in Zig development

Resources

Practical Rateless Set ReconciliationAug 2024paper Gossipsub v2.0 specificationDec 2024specs Generalised Gossipsub specificationMar 2025specs Eth P2P: How Ethereum Talks to ItselfNov 2025presentation

Lead:Raúl Kripalani

Scaling

Attester-Proposer Separation

Progress20%

Separates the roles of block proposers and attesters in Ethereum consensus to reduce centralization pressures, enable more efficient MEV handling, and improve overall network decentralization.

Key Milestones

Exploratory research

Resources

Attester-Proposer Separation Trackerwebsite Unbundling Staking: Towards Rainbow StakingFeb 2024article Attester-Proposer Separation Seminar Presentation at King's College LondonJan 2025presentation Toward a General Model for Proposer Selection Mechanism DesignFeb 2025article Rainbow Roles Incentives: ABPS, FOCIL + ASFeb 2025article

Lead:TBD

ConsensusScaling

Faster Finality

Progress50%

Reduces Ethereum finality from ~15 minutes to seconds using 3-slot finality (3SF) — a practical alternative to single-slot finality that balances speed, security, and implementation complexity while integrating with ePBS, FOCIL, and PeerDAS.

Key Milestones

Exploratory research

Resources

A Simple Single Slot Finality Protocol For EthereumFeb 2023paper 3-Slot Finality: SSF Is Not About Single SlotNov 2024article Integrating 3SF with ePBS, FOCIL, and PeerDASAug 2025article LMD GHOST with ~256 Validators and a Fast-Following Finality GadgetAug 2025article

Lead:Barnabé Monnot

ConsensusScaling

Client Implementations

Ream

Rust

The high-performance Lean Consensus client written in Rust, focusing on delivering the most performant and user-friendly Lean Consensus client.

Repository

ReamLabs/ream

Web Twitter GitHub Docs

Zeam

Zig

The Zig-based client team focused on representing Asia in the Ethereum ecosystem, building foundational components and integrating with various ZKVMs.

Repository

blockblaz/zeam

Twitter GitHub

Qlean-mini

C++

The blockchain infrastructure team with expertise in networking and C++, notably maintaining a C++ libp2p library previously used in Polkadot.

Repository

qdrvm/qlean-mini

Web Twitter GitHub

Lantern

By Pier Two. C-based Ethereum Lean Consensus client. Focused on enabling devices with limited compute to follow the consensus.

Repository

Pier-Two/lantern

Web Twitter GitHub

Lighthouse

Rust

A Lighthouse fork for Lean Consensus, leveraging the battle-tested Rust codebase.

Repository

hopinheimer/lighthouse

Web Twitter GitHub

Learning Resources

General Resources

2025

Next 10 Years of Ethereum by Fede - Devconnect(Nov 2025)
Ethereum (Roadmap) in 30min by Vitalik Buterin - Devconnect(Nov 2025)
leanEthereum 2025 progress recap by Justin Drake(Nov 2025)
lean week 2025 recap by Will Corcoran(Oct 2025)
lean Ethereum by Justin Drake(Jul 2025)
Future of Ethereum: Beam Chain by Seungmin Jeon(Jan 2025)
Twitter post on the beam chain roadmap by Vitalik Buterin(Jan 2025)

2024

Ethereum's Three Front War on Bankless Podcast(Dec 2024)
Keynote: [title redacted] at Devcon SEA(Nov 2024)
Ethereum Roadmap & Beamchain at Bankless Summit(Nov 2024)
Deep Dive into Ethereum's Beam Chain with The Defiant(Nov 2024)
Beam chain tldr at Devcon SEA Community-Led Session(Nov 2024)

leanConsensus Calls

Lean Call #1: Social Layer Updates

February 14, 2025

The kickoff call covering social layer progress, funding structures, legal updates, introductions of research specialists and client teams, and coordinator presentations

Resources:

Meeting agenda Presentation slides

Watch on YouTube

Lean Call #2: Post-Quantum Security

February 28, 2025

Technical updates on post-quantum cryptography solutions, featuring technical presentations from researchers on signature schemes, hash functions, minimal zkVMs, and formal verification.

Resources: