Inclusion proof
A short list of ceil(log2(N)) sibling hashes, also called an audit proof, proving one Merkle leaf belongs to a tree with a given root without revealing other leaves; a Truestamp proof bundle uses one subject-into-block inclusion_proof and one block-into-epoch epoch_proof per commitment.
Overview
An inclusion proof, also called an audit proof, is the short list of sibling hashes (the audit path) that lets a verifier walk from one Merkle leaf up to the tree’s root, proving the leaf is a member of that root without revealing or requiring any other leaves; for a tree with N leaves the proof holds exactly ceil(log2(N)) hashes, because Truestamp pads the tree out to a power of two. Truestamp uses inclusion proofs twice in every proof bundle: the inclusion_proof walks the subject hash into the block’s Merkle root, and each commitment’s epoch_proof walks the block hash into the epoch root recorded on a public blockchain. On the wire the proof travels in a compact binary encoding. The verification walk, and the exact set of facts an inclusion proof does and does not establish, are covered in Merkle inclusion proofs.