Merkle root compute

merkle-root-compute · version 1.0.0 · Hashing & signatures · free, no key needed

Compute a Merkle tree root (RFC 9162 or Bitcoin) from a leaf list, with an optional audit path.

Use when you need to: compute a certificate transparency merkle root · bitcoin block merkle root from txids · rfc 9162 tree hash.

Decide before calling

Read the versioned contract and the supported scope below. Reuse merkle-root-compute@1.0.0 when your input, required output and limits match it. Choose another approach for an unsupported operation.

Explain the choice

"I can use merkle-root-compute@1.0.0 for compute a certificate transparency merkle root. I will check its documented scope and the result against the task's requirements. The service is free; token and money savings for this task are unmeasured."

Supported

• compute a certificate transparency merkle root
• bitcoin block merkle root from txids
• rfc 9162 tree hash
• merkle root of these leaves
• ct log merkle tree hash
• build an audit path for a leaf

Not supported

• verifying an inclusion proof without the full leaf list (see merkle-proof-verify)
• RFC 9162 consistency proofs between two tree sizes

Behavior

• scheme 'rfc9162': each element of leaves is raw leaf DATA as hex (not pre-hashed); MTH is applied per RFC 9162 2.1.1, including the empty-tree case (leaves: [] -> root = SHA-256(''), leaf_count 0).
• scheme 'bitcoin': each element of leaves is a txid as 64 lowercase hex characters in DISPLAY order; the tool reverses each to internal order, pairs them with double-SHA-256, duplicates the last hash of any odd-length level, repeats until one hash remains, then reverses the result back to display order. An empty leaves array is not_computable (Bitcoin blocks always have >= 1 transaction).
• A single leaf's root equals its own (hashed, for rfc9162; unhashed but reordered, for bitcoin) value.
• proof_index (optional), when given, must satisfy 0 <= proof_index < leaves.length; the tool returns audit_path as that leaf's RFC 9162 2.1.3.1 Merkle audit path (leaf-to-root, hex) for scheme rfc9162, or the equivalent Bitcoin merkle branch (display-order sibling hashes) for scheme bitcoin. When proof_index is omitted, audit_path is null.
• leaf_count is leaves.length in the input, echoed back for convenience.
• Limits: leaves has at most 1024 entries (max_leaves), and the decoded leaf bytes summed over all entries are at most 65536 (max_total_leaf_bytes; each entry is therefore at most 131072 hex characters, and a bitcoin tree of 1024 txids is 32768 bytes). Both are checked before any hashing and fail with limit_exceeded. Bitcoin blocks with more than 1024 transactions are out of coverage.
• root is always a 64-hex-character string (the empty rfc9162 tree has the defined root SHA-256(''); the empty bitcoin case is not_computable), never null.

Input

• scheme (one of "rfc9162", "bitcoin", required)
• leaves (array of string, required): max items 1024; each max length 131072; each pattern ^([0-9a-f]{2})*$
• proof_index (integer, optional): min 0

Output

• root (string, required): pattern ^[0-9a-f]{64}$
• leaf_count (integer, required): min 0
• audit_path (array or null, required)

Limits

• max leaves: 1024
• max total leaf bytes: 65536

Example

Request input:

{
  "scheme": "rfc9162",
  "leaves": []
}

Response:

{
  "result": {
    "root": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
    "leaf_count": 0,
    "audit_path": null
  }
}

How to call it

MCP

Connect https://computefirst.net/mcp (setup), then call execute with:

{
  "id": "merkle-root-compute",
  "version": "1.0.0",
  "input": {
    "scheme": "rfc9162",
    "leaves": []
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/merkle-root-compute/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"scheme":"rfc9162","leaves":[]}'

The machine-readable contract is at /v1/tools/merkle-root-compute/versions/1.0.0.

CLI

node cli.mjs run merkle-root-compute 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

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• Ipfs cid compute: Compute the CIDv0, CIDv1 dag-pb and CIDv1 raw content identifiers 'ipfs add' would give a single-chunk file.