Merkle Proof

A Merkle proof, also called an inclusion proof, is a short list of hashes showing that a specific transaction really is part of a block, without the verifier having to download every transaction in it. The prover supplies the sibling hashes along the path from that transaction up to the Merkle root; the verifier recomputes the chain of hashes and checks that the final value matches the root already stored in the block header. Light wallets, cross-chain bridges and rollups rely on this to verify data cheaply. Note what it does not prove: a Merkle proof only demonstrates membership in one particular tree, not that the block containing it is on the canonical chain.