Ethereum Lean Consensus Client

The Provable Consensus Client

theorem state_transition_correct : ∀ s b, verify (transition s b) = true

Why Verity

Security Through
Mathematical Proof

Where other clients test for correctness, Verity proves it. Formal verification closes the gap between specification and implementation — permanently.

Formally Verified

Every line of consensus logic is mathematically proven correct. Specification drift is structurally impossible, and entire bug classes are ruled out before the code ever runs.

Ecosystem Contribution

Purpose-built for Ethereum's Lean Consensus roadmap. Verity adds a qualitatively different kind of client diversity — one backed by mathematical certainty rather than independent reimplementation.

Transparent Assurance

Every proof is open source and machine-checkable. Anyone can independently verify that Verity's implementation matches the Ethereum specification.

How it Works

A Different Pipeline

Traditional clients translate specs by hand. Verity proves them mathematically.

Traditional Client

Read Specification

Human interprets the spec document

Manual Implementation

Re-write logic in Rust, Go, etc.

Test & Hope

Unit tests, fuzz tests, audits

⚠

Spec–implementation gap remains. Edge cases may hide undetected until production.

Verity

Encode Specification in Lean 4

Spec becomes machine-checkable types

Prove Correctness

Lean 4 type checker verifies every path

Call from Rust via FFI

Rust client invokes proven Lean 4 core logic

✓

Core consensus logic is mathematically verified in Lean 4 and called from Rust via FFI — no re-implementation, no divergence.

Roadmap

Development Progress

Our path toward a formally verified, production-ready consensus client.

2026 — Building

Core State Transition Proofs & Devnet Participation

Proving correctness of 3SF consensus, PQ signature verification, and attestation logic. Joining Lean Consensus devnets alongside Ream, Zeam, Qlean, and other client teams.

2027 — Testing

Verified Client Alpha

First runnable client with verified core components — syncing and following the beacon chain on testnets. Public alpha for community testing and feedback.

2028+

Mainnet-Ready Stable Release

Production-ready client with comprehensive formal verification, performance optimization, and full Lean Consensus protocol compliance.

Vision

What We're Building Toward

Build the most secure Ethereum consensus client — one whose correctness is not tested but mathematically proven, setting a new standard for what it means to trust blockchain infrastructure.

Lean 4

Language

100%

Open Source

Spec-Impl Gap

∞

Test Coverage*