merkle batching - XibalbaTechSol/integrity-core GitHub Wiki

title: Merkle Batching & Anchoring Convention created: 2026-07-07 updated: 2026-09-15 type: concept tags: [cryptography, layer-2] confidence: high source_files:

  • docs/INTERFACE_CONTRACT.md

Table of contents

Overview

Batches of approved BCC commitments are anchored on-chain as a single Merkle root, verified by StateAnchor.sol in contracts.

  • Hash function: keccak256 (not SHA-256) โ€” cheap and native in the EVM, since the root is verified on-chain.
  • Leaf: keccak256(abi.encodePacked(leafData)).
  • Parent: sort the pair of child hashes ascending before concatenating โ€” keccak256(a < b ? a,b : b,a) โ€” the standard OpenZeppelin MerkleProof convention. This lets on-chain verification use MerkleProof.verify directly instead of a bespoke verifier.

This is the one hashing convention every package touching Merkle trees/proofs (contracts, integrity-oracle, bcc_middleware) must share exactly โ€” a mismatch here silently breaks proof verification. See Interface Contract ยง4.4.