TYPE 0x0806 · GOVERNANCE FAMILY

ACCUMULATOR

Merkle set membership proof. Verifies that a value belongs to a committed set using sorted-pair Merkle proofs. The conditions commit to a Merkle root; the witness provides the leaf and proof path. No Tapscript equivalent.

Governance Invertible

Ladder Diagram

Fields

Field	Data Type	Size	Side	Description
merkle_root	HASH256	32 B	Conditions	Root of the Merkle tree committing to the allowed set
siblings[0..N]	HASH256	32 B each	Witness	Sibling hashes from leaf to root (proof path). One per tree level.
leaf	HASH256	32 B	Witness	The leaf hash being proven (last HASH256 field in the block)

Minimum 3 HASH256 fields required: root + at least 1 sibling + leaf. Fields are ordered: [root, sibling_0, sibling_1, ..., leaf].

Wire Format Breakdown

Example: depth-2 tree (4 leaves), proving membership of one leaf:

0x0806 0 1 HASH256 · root Conditions = 38 bytes

0x0806 0 3 HASH256 · sib0 HASH256 · sib1 HASH256 · leaf Witness = 106 bytes

Total (depth 2) 144 bytes

Witness grows by 34 bytes per tree level (1B type + 1B len + 32B hash).

Evaluation Logic

1.Extract all HASH256 fields. If fewer than 3 → ERROR

2.First hash = root, last hash = leaf, middle hashes = proof siblings

3.Start with current = leaf

4.For each sibling: current = SHA256(min(current, sibling) || max(current, sibling))

5.If computed root == committed root → SATISFIED

6.Otherwise → UNSATISFIED

Sorted pair convention: At each level, the two children are sorted lexicographically before hashing. This makes the proof deterministic — no left/right direction bits needed, saving 1 bit per level.

JSON Wire Format

Conditions (commit to set root)

{
  "type": "ACCUMULATOR",
  "fields": [
    { "type": "HASH256", "hex": "a1b2c3d4...merkle root...32 bytes" }
  ]
}

Witness (prove membership)

{
  "type": "ACCUMULATOR",
  "fields": [
    { "type": "HASH256", "hex": "...sibling at level 0..." },
    { "type": "HASH256", "hex": "...sibling at level 1..." },
    { "type": "HASH256", "hex": "...leaf being proven..." }
  ]
}

Use Cases

Whitelist Authorization

Commit to a Merkle root of allowed transaction hashes, pubkey hashes, or output scripts. Only transactions that can prove membership in the committed set are valid spends. The set can contain millions of entries with only 32 bytes on-chain.

Inverted: Blacklist Enforcement

With the inverted flag, spending is blocked if the leaf IS in the set. Creates exclusion lists — e.g., block specific output patterns or addresses from being created.

Merkle Airdrops

Covenant output commits to a Merkle root of eligible claimants. Each claimant proves their pubkey hash is in the tree to claim their share. Scales to millions of recipients with O(log N) proof size.

Oracle Data Attestation

Oracle publishes a Merkle root of attested facts. Contract verifies a specific fact by checking its Merkle proof against the committed root, enabling trustless off-chain data verification.

← RELATIVE_VALUE P2PK_LEGACY →