DA-01 · LESSON 06

The Bitcoin enforcement boundary

KEY DEFINITIONS

Terms used in this lesson

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

Bitcoin enforces committed transaction and Script conditions, while richer Ducat state and economic rules are reconstructed and checked by protocol participants.

45 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
REQUESTThe Bitcoin enforcement boundary
The The Bitcoin enforcement boundary 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, The Bitcoin enforcement boundary. The The Bitcoin enforcement boundary 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

Compare economic meaning with Bitcoin validity using a vector that differs from required practice instead of using the vague label invalid.

MECHANISM

Full nodes reject missing inputs, overspending, invalid signatures, failed scripts, and other consensus violations.

AFTER

Bitcoin enforces the spend conditions committed in the transaction. Ducat software adds protocol interpretation. A transaction can pass one layer and fail the other.

Text equivalent: Starting from Compare economic meaning with Bitcoin validity using a vector that differs from required practice instead of using the vague label invalid. The mechanism begins when Full nodes reject missing inputs, overspending, invalid signatures, failed scripts, and other consensus violations. The resulting lesson is Bitcoin enforces the spend conditions committed in the transaction. Ducat software adds protocol interpretation. A transaction can pass one layer and fail the other.

2. Mechanism pathSelect a stage to inspect its job

STAGE 1 OF 4

List Bitcoin checks

Full nodes reject missing inputs, overspending, invalid signatures, failed scripts, and other consensus violations.

Complete path: 1. List Bitcoin checks: Full nodes reject missing inputs, overspending, invalid signatures, failed scripts, and other consensus violations. 2. List Ducat checks: Protocol code interprets action tags, runestones, vault differentials, oracle context, account use, and successor-object relationships. 3. Find overlaps: A Guardian policy may refuse a transaction that Bitcoin would accept, while a malformed witness is rejected by Bitcoin even if an application wanted it. 4. State the final claim precisely: Ducat anchors assets and spending conditions in Bitcoin without making every economic rule part of Bitcoin consensus.

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. Ducat anchors assets and spending conditions in Bitcoin without making every economic rule part of Bitcoin consensus.

CHANGED CONDITION

A missing, malformed, stale, unauthorized, or inconsistent required input stops at its first named boundary. Bitcoin enforces only the transaction and Script commitments it understands. Ducat-specific state, policy, price, and economic checks retain external…

Important distinction: Bitcoin-native means every Ducat rule is Bitcoin consensus. Bitcoin enforces only the transaction and Script commitments it understands. Ducat-specific state, policy, price, and economic checks retain external assumptions.

Text equivalent: The accepted path is enforced by The worked case executes the named inputs and checks in the displayed order. Ducat anchors assets and spending conditions in Bitcoin without making every economic rule part of Bitcoin consensus. If the required condition changes, A missing, malformed, stale, unauthorized, or inconsistent required input stops at its first named boundary. Bitcoin enforces only the transaction and Script commitments it understands. Ducat-specific state, policy, price, and economic checks retain external assumptions.

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Learn the idea

An enforcement boundary tells you which machine rejects an invalid action. Bitcoin consensus enforces spent outpoints, values, signatures, Script, and satoshi conservation. A differential is the signed arithmetic change between a current state and its successor, for example successor debt minus current debt for a borrow. Ducat validators and Guardians enforce additional protocol meanings, including matching that debt differential to issued or burned UNIT, that Bitcoin does not understand.

GUIDED EXPLANATION1/4 ideas inspected

List Bitcoin checks

Full nodes reject missing inputs, overspending, invalid signatures, failed scripts, and other consensus violations.

The worked example follows the explanation

Inspect every idea above to open it.

Important distinction“Bitcoin-native means every Ducat rule is Bitcoin consensus.”

Bitcoin enforces only the transaction and Script commitments it understands. Ducat-specific state, policy, price, and economic checks retain external assumptions.

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.