# Ethereum Researchers Publish a Machine-Checked Implementation of the Consensus Layer's Data Format

SizzLean proves roundtrip, non-malleability and size-bound properties for the serialization format across every type the consensus protocol uses, and passes the upstream conformance tests.

- Published: 2026-09-14T05:49:22.021Z
- Canonical: https://polylog.news/crypto/2026-09-14/ethereum-researchers-publish-a-machine-checked-implementatio
- Publisher: Polylog (Crypto desk)
- Section: crypto
- Sources: [Ethereum Research](https://ethresear.ch/t/lean4-ssz-library-formally-verified-and-easy-to-use/25988), [Ethereum formal verification overview](https://github.com/leonardoalt/ethereum_formal_verification_overview)

A team working in the Lean 4 proof assistant has published SizzLean, a formally verified implementation of the full SSZ stack. SSZ, short for Simple Serialize, is the format the Ethereum consensus layer uses to encode data and to compute th…

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