Linea Block Verifier

⚠️ This repository is no longer maintained by the core team. Community contributions are welcome.

⚠️ This library has not been audited. Use at your own risk.

Cryptographically verify Linea blocks using beacon chain attestations and sequencer signatures.

Context in Malda Sequencer

This library was created as a direct build dependency of the ZkCoprocessor within the Malda Sequencer. The ZkCoprocessor relies on it to cryptographically verify Linea blocks before processing them further.

While built specifically for Linea's consensus model, the verification logic is implemented in a generic way and can be adapted for use in other projects that need similar block verification capabilities.

Overview

This project provides tools to prove that a Linea block hash or header is authentic by verifying the sequencer's ECDSA signature. It's designed for use in zkVM environments where trustless verification is required.

For detailed security model and verification logic, see SECURITY.md.

Crates

Crate	Description
linea-block-verifier	Umbrella crate re-exporting core and host
linea-proof-core	Core verification logic (for zkVM) and basic types
linea-proof-host	Host utilities: beacon client, RPC helpers
verify-header-demo	CLI demo for header verification

zkVM

Crate	Description
zkvm/risc0-guest	RISC Zero guest program for zkVM verification
zkvm/risc0-host	RISC Zero host for executing the guest

Verification Modes

Mode	Description	Use Case
verify_block_hash	Verifies only the block hash	Faster, minimal proof that block hash is authentic
verify_header	Verifies full header + Linea bug detection	Complete validation with field-by-field checks

Usage

Demo CLI

# Verify a recent block on Sepolia
cargo run -p verify-header-demo -- --network sepolia recent

# Verify a recent block on Mainnet
cargo run -p verify-header-demo -- --network mainnet recent

# Verify a block hash only (without full header)
cargo run -p verify-header-demo -- --network mainnet hash \
  --block-hash 0x6d93533ba354440c035355657195dd7832df0ac3d232904d08e67296fd5ce75c

# Verify from local JSON file
cargo run -p verify-header-demo -- --network mainnet local --file-path header.json

Library Usage

Use the umbrella crate for convenience:

# For host applications (includes BeaconClient)
linea-block-verifier = { version = "0.1", features = ["host"] }

# For zkVM guests (no_std compatible)
linea-block-verifier = { version = "0.1", features = ["std"] }

use linea_block_verifier::core::{verify_header, verify_block_hash, LineaNetwork};
use linea_block_verifier::host::BeaconClient;

// Fetch beacon data
let client = BeaconClient::new("http://beacon-rpc:10080", LineaNetwork::Mainnet);
let verify_input = client.create_verify_input(header).await?;

// Option 1: Verify block hash only (faster)
verify_block_hash(block_hash, &beacon_data, LineaNetwork::Mainnet)?;

// Option 2: Verify full header with Linea bug detection
verify_header(&input_header, &beacon_data, LineaNetwork::Mainnet)?;

RISC Zero zkVM

The zkvm/ directory contains RISC Zero integration for generating zero-knowledge proofs of header verification.

# Build and run the RISC Zero host
cd zkvm/risc0-host
cargo run --release

The host will:

1. Fetch a recent Linea block and beacon data (or load from verify_input.bin if cached)
2. Execute both verification modes in the zkVM
3. Report cycle counts and timing comparison

Building

cargo build --release

Nix

A flake.nix is provided for reproducible builds, no_std compatibility checking, linting, and formatting.

# Build verify-header-demo
nix build .#verify-header-demo

# Build linea-proof-core for thumbv7em-none-eabi (verifies no_std compatibility)
nix build .#linea-proof-core-no-std

# Run all checks (builds + clippy + formatting)
nix flake check

# Format code (Nix + Rust)
nix fmt

# Enter development shell
nix develop

Testing

cargo test

License

This project is licensed under the MIT License.

References

• Linea V4 Beta Migration Guide
• Maru Consensus
• Linea Documentation