Merkle leaf
The bottom-level entry of a Merkle tree, hashed as SHA-256(0x00 || hash) under the reserved leaf prefix so it can never be confused with an interior node (prefix 0x01); block-tree leaves are item and entropy observation hashes, epoch-tree leaves are block hashes.
Overview
A Merkle leaf is a bottom-level entry of a Merkle tree: one input item, represented by its 32-byte SHA-256 hash. Leaves are hashed under the reserved leaf prefix, leaf = SHA-256(0x00 || hash), while interior nodes use the 0x01 prefix, so a leaf hash can never be passed off as a node hash or vice versa; this domain separation is explained in Truestamp’s Merkle tree and, system-wide, in hashing domain separation. In a Truestamp block’s tree the leaves are the item hashes and entropy observation hashes committed in that block; in an epoch’s tree the leaves are block hashes.