{
  "slug": "merkle-tree",
  "term": "Merkle tree",
  "aliases": [
    "Hash tree"
  ],
  "definition": "A Merkle tree combines hashes of data and child nodes into a root so that selected entries or subtrees can be checked without transferring the entire data set.",
  "note": "Dynamo's 2007 design uses per-key-range trees to locate divergent replicas. [dynamo2007] For inclusion verification, use the intended trusted root and the construction's encoding, ordering and tree-shape rules. RFC 9162 specifies distinct leaf and internal-node prefixes and includes tree size and leaf index in proof verification; that is one construction, not a universal storage format. [rfc9162]",
  "status": "shipping",
  "advantages": [],
  "limitations": [
    {
      "text": "A proof relative to a root does not by itself establish freshness, data availability or which divergent replica is authoritative.",
      "citationIds": [
        "rfc9162",
        "dynamo2007"
      ]
    },
    {
      "text": "A Merkle tree does not reconstruct missing data; replica synchronization still needs the relevant data and reconciliation rules.",
      "citationIds": [
        "dynamo2007"
      ]
    }
  ],
  "related": [
    "cryptographic-hash",
    "hash-collision",
    "checksum",
    "end-to-end-data-protection"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "citations": [
    {
      "id": "dynamo2007",
      "title": "DeCandia et al. Dynamo: Amazon's Highly Available Key-value Store. SOSP 2007, section 4.7.",
      "url": "https://www.allthingsdistributed.com/files/amazon-dynamo-sosp2007.pdf",
      "accessed": "2026-10-12"
    },
    {
      "id": "rfc9162",
      "title": "RFC 9162: Certificate Transparency Version 2.0, sections 2.1 and 4.9-4.12",
      "url": "https://www.rfc-editor.org/rfc/rfc9162.html",
      "accessed": "2026-10-12"
    },
    {
      "id": "hesela-integrity",
      "title": "Hesela: Why a valid checksum can still return the wrong data",
      "url": "https://hesela.com/analyses/checksums-identity-and-lost-writes/",
      "accessed": "2026-10-12"
    }
  ],
  "updated": "2026-10-12"
}