DA-03 · LESSON 07

Vault metadata versus enforcement

KEY DEFINITIONS

Terms used in this lesson

Vault: A set of Bitcoin outputs and spending rules that holds collateral and represents the current loan state.
OP_RETURN: A Bitcoin Script operation commonly used to create an unspendable output carrying a small amount of data.
Witness: Signatures, scripts, or other data supplied to satisfy a Bitcoin output’s spending condition.
Runestone: Transaction data interpreted by the Runes protocol to describe token creation or allocation.
Taproot: A Bitcoin output and spending design that can combine a public-key path with privately committed alternative scripts.
Guardian: A Ducat policy-checking signer that can authorize or reject defined protocol transactions.
Oracle: A system that reports outside information, such as a market price, for use by a protocol.
BTC: The common market ticker for bitcoin.
UNIT: Ducat’s dollar-pegged stablecoin, the asset a borrower can create against bitcoin collateral.
Validator: Software or a participant that independently checks state transitions under a system's rules. The exact role depends on the protocol being discussed.

OP_RETURN records help reconstruct state, but spend authorization comes from committed Script paths and signatures rather than metadata alone.

55 min Difficulty 4/5 Not started

VISUAL MODEL

See the whole mechanism before going step by step

Use the diagrams to orient yourself. Then the guided explanation below teaches every part in depth.

4 explanatory views

CONCEPT-SPECIFIC MAP · ducat vaultA Ducat action moves one Bitcoin-anchored vault state to a successorSelect any state to inspect its exact role.

RELATIONSHIP MAPInputs, rule, and outputs

01
PREDECESSORCurrent vault outpoint
The current Bitcoin output anchors collateral and identifies the state being spent.
02
REQUESTVault metadata versus enforcement
The Vault metadata versus enforcement workflow proposes one exact action and successor state.
03
POLICYProfile, oracle, signatures
Applicable policy, price evidence, authorization, and transaction shape are checked.
04
BITCOIN SPENDScript-valid transaction
Bitcoin miners and nodes can include only a transaction that satisfies Bitcoin rules.
05
SUCCESSORNew outpoint and state
Ducat validators reconstruct debt, collateral, token, and account changes from the confirmed transaction.

Rule shown: Bitcoin checks the spend; Ducat components independently reconstruct and validate the additional protocol state.

STAGE 1 OF 5PREDECESSOR: Current vault outpoint

The current Bitcoin output anchors collateral and identifies the state being spent.

Governing relationship: Bitcoin checks the spend; Ducat components independently reconstruct and validate the additional protocol state. Complete path: 1. PREDECESSOR, Current vault outpoint. The current Bitcoin output anchors collateral and identifies the state being spent. 2. REQUEST, Vault metadata versus enforcement. The Vault metadata versus enforcement workflow proposes one exact action and successor state. 3. POLICY, Profile, oracle, signatures. Applicable policy, price evidence, authorization, and transaction shape are checked. 4. BITCOIN SPEND, Script-valid transaction. Bitcoin miners and nodes can include only a transaction that satisfies Bitcoin rules. 5. SUCCESSOR, New outpoint and state. Ducat validators reconstruct debt, collateral, token, and account changes from the confirmed transaction.

1. State transitionWhat exists, what changes, and what results

BEFORE

Use a 0.8 BTC vault with 30,000 UNIT debt and a proposed 0.15 BTC owner withdrawal. Required practice uses different messages and amounts.

MECHANISM

Sequence fields, action tags, runestones, inscriptions, or OP_RETURN records make the transaction parseable by Ducat software.

AFTER

OP_RETURN describes the action but cannot authorize the spend or override either validator. Required practice uses a separate server-executed vector.

Text equivalent: Starting from Use a 0.8 BTC vault with 30,000 UNIT debt and a proposed 0.15 BTC owner withdrawal. Required practice uses different messages and amounts. The mechanism begins when Sequence fields, action tags, runestones, inscriptions, or OP_RETURN records make the transaction parseable by Ducat software. The resulting lesson is OP_RETURN describes the action but cannot authorize the spend or override either validator. Required practice uses a separate server-executed vector.

2. Mechanism pathSelect a stage to inspect its job

STAGE 1 OF 4

Encode the action

Sequence fields, action tags, runestones, inscriptions, or OP_RETURN records make the transaction parseable by Ducat software.

Complete path: 1. Encode the action: Sequence fields, action tags, runestones, inscriptions, or OP_RETURN records make the transaction parseable by Ducat software. 2. Commit spend conditions: Taproot outputs commit the owner, Guardian, oracle, and alternative Script paths that constrain future spends. 3. Validate both layers: Bitcoin checks the witness against the output; Ducat parsers check metadata and state-transition relationships. 4. Reject false descriptions: Metadata claiming a valid withdrawal does not override a missing signature, failed script, wrong prior vault, or invalid successor differential.

3. Rule and failure boundaryWhat accepts the result and where it can stop

ACCEPTED PATH

The worked case executes the named inputs and checks in the displayed order. Metadata claiming a valid withdrawal does not override a missing signature, failed script, wrong prior vault, or invalid successor differential.

CHANGED CONDITION

A missing, malformed, stale, unauthorized, or inconsistent required input stops at its first named boundary. Bitcoin commits and orders the bytes. Ducat software supplies their extra interpretation unless the value is also tied to a Script condition.

Important distinction: Because metadata is on Bitcoin, Bitcoin consensus enforces every field's Ducat meaning. Bitcoin commits and orders the bytes. Ducat software supplies their extra interpretation unless the value is also tied to a Script condition.

Text equivalent: The accepted path is enforced by The worked case executes the named inputs and checks in the displayed order. Metadata claiming a valid withdrawal does not override a missing signature, failed script, wrong prior vault, or invalid successor differential. If the required condition changes, A missing, malformed, stale, unauthorized, or inconsistent required input stops at its first named boundary. Bitcoin commits and orders the bytes. Ducat software supplies their extra interpretation unless the value is also tied to a Script condition.

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Learn the idea

Vault metadata is transaction data that lets Ducat software identify an action and reconstruct fields. Enforcement is the Bitcoin spending condition that must actually succeed. OP_RETURN metadata can describe a state change but cannot spend or protect bitcoin by itself.

GUIDED EXPLANATION1/4 ideas inspected

Encode the action

Sequence fields, action tags, runestones, inscriptions, or OP_RETURN records make the transaction parseable by Ducat software.

The worked example follows the explanation

Inspect every idea above to open it.

Important distinction“Because metadata is on Bitcoin, Bitcoin consensus enforces every field's Ducat meaning.”

Bitcoin commits and orders the bytes. Ducat software supplies their extra interpretation unless the value is also tied to a Script condition.

FINISH LEARNING FIRST

The questions unlock after every required learning activity

Inspect every guided idea, open the worked example, rebuild its mechanism, and complete the deterministic lesson tool. Your progress is saved automatically.