DA-05 · LESSON 02

Blind price ladder

KEY DEFINITIONS

Terms used in this lesson

Oracle: A system that reports outside information, such as a market price, for use by a protocol.
Collateral: An asset pledged against a debt; it can be used to cover the debt if agreed conditions are breached.
Vault: A set of Bitcoin outputs and spending rules that holds collateral and represents the current loan state.
BTC: The common market ticker for bitcoin.
USD: United States dollar, the reference currency in a BTC/USD price.
Hash160: SHA-256 followed by RIPEMD-160, producing the 20-byte hash used by several Bitcoin spending conditions.
HMAC: Hash-based message authentication code: a keyed hash construction used to authenticate data or derive deterministic secret material.
HTTP: Hypertext Transfer Protocol: a request-and-response protocol commonly used between web services.

The oracle publishes pre-committed threshold events across collateral-rate buckets so it need not know which users selected which thresholds.

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
REQUESTBlind price ladder
The Blind price ladder 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, Blind price ladder. The Blind price ladder 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 the captured test configuration: base price $100,000, liquidation threshold 1.35, rates 1.35 through 10.00 inclusive, step 0.01, and at most 130 events per publish call.

MECHANISM

The workflow uses an authenticated BTC/USD base price, timestamp, network, oracle key, rate range, and step size.

AFTER

The workflow derives 866 contracts and sends chunk sizes 130, 130, 130, 130, 130, 130, and 86. These are captured test values, not claimed live settings.

Text equivalent: Starting from Use the captured test configuration: base price $100,000, liquidation threshold 1.35, rates 1.35 through 10.00 inclusive, step 0.01, and at most 130 events per publish call. The mechanism begins when The workflow uses an authenticated BTC/USD base price, timestamp, network, oracle key, rate range, and step size. The resulting lesson is The workflow derives 866 contracts and sends chunk sizes 130, 130, 130, 130, 130, 130, and 86. These are captured test values, not claimed live settings.

2. Mechanism pathSelect a stage to inspect its job

STAGE 1 OF 4

Read one base snapshot

The workflow uses an authenticated BTC/USD base price, timestamp, network, oracle key, rate range, and step size.

Complete path: 1. Read one base snapshot: The workflow uses an authenticated BTC/USD base price, timestamp, network, oracle key, rate range, and step size. 2. Derive each threshold price: For every configured rate, the captured workflow calculates the price at which that collateral ratio would be breached. 3. Commit a hidden secret: Each threshold contract contains a commitment and Hash160 of HMAC-derived secret material, but not the secret itself. 4. Publish all ladder chunks: Wallets can choose a contract without telling the oracle which vault uses it.

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. Wallets can choose a contract without telling the oracle which vault uses it.

CHANGED CONDITION

A missing, malformed, stale, unauthorized, or inconsistent required input stops at its first named boundary. The oracle calculates every configured threshold. It is blind only to which published commitment a user chooses for a vault.

Important distinction: Blind means the oracle cannot calculate the threshold prices. The oracle calculates every configured threshold. It is blind only to which published commitment a user chooses for a vault.

Text equivalent: The accepted path is enforced by The worked case executes the named inputs and checks in the displayed order. Wallets can choose a contract without telling the oracle which vault uses it. If the required condition changes, A missing, malformed, stale, unauthorized, or inconsistent required input stops at its first named boundary. The oracle calculates every configured threshold. It is blind only to which published commitment a user chooses for a vault.

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Learn the idea

A threshold ladder is a set of price contracts across configured collateral-rate steps. Blind means the oracle publishes commitments for every step without learning which one a particular vault later embeds.

GUIDED EXPLANATION1/4 ideas inspected

Read one base snapshot

The workflow uses an authenticated BTC/USD base price, timestamp, network, oracle key, rate range, and step size.

The worked example follows the explanation

Inspect every idea above to open it.

Important distinction“Blind means the oracle cannot calculate the threshold prices.”

The oracle calculates every configured threshold. It is blind only to which published commitment a user chooses for a vault.

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.