Proof of Reserve Oracle

DIA oracles helped to deliver Lightning Network node balance data to Ethereum, enabling strBTC holders to verify their Bitcoin backing on-chain.

1. Oracle Details

1.1. Reserve Feeds

The reserve feeds are consumable via the adapter contract tracking on-chain & off-chain reserves.

Reserve Query Key	Reserve Oracle Address (Combined Reserves)	Adapter Address (Chainlink-Compatible)
STROOM-Reserves	0x12DB8fcA6AAA29E922bFAD8a7771aE11F17a1811	0x1d18b5147B11908B24A247517F606c0705CF8d40

1.2. Contracts

The DIAOracleV2 contract calculates the off-chain reserves.

Blockchain	Address
Ethereum Mainnet	0xFe0593fA61c7Cf3D2CD17b8B53Ef844A33b0463d

1.3. Oracle Configuration

Settings that dictate how the oracle computes and updates data.

Setting	Rate
Deviation (%) & Refresh Frequency	0.5% and 120 seconds
Heartbeat	24h

1.4. Oracle Configuration

1.4.1. On-chain Sources

Contract	Asset Address	Owner Address
wBTC <-> strBTC converter	0x2260FAC5E5542a773Aa44fBCfeDf7C193bc2C599	0x56192F14C1d84e41Db3d5d4C5d407EFDB5CB1352
cbBTC <-> strBTC converter	0xcbB7C0000aB88B473b1f5aFd9ef808440eed33Bf	0xe7b4c44adB17147Ad877EB8607EEB1e95AdF2cD0

1.4.2. Off-chain Sources

Lightning Service	Query Endpoints
WalletBalance	Return total_balance
ChannelBalance	Return the sum of local_balance, unsettled_local_balance,& pending_open_local_balance
PendingChannels	Return total_limbo_balance

2. How the Oracle Works

The DIA adapter (DIAStroomAdapter) calculates the total BTC reserves by combining two data sources:

1. On-chain reserves: the sum of WBTC and cbBTC balances from Stroom converter contract addresses on Ethereum.

2. Off-chain reserves: the sum of WalletBalance API (total_balance) and ChannelBalance API (local_balance + unsettled_local_balance + pending_open_local_balance) with 8-decimal satoshi precision. The DIA oracle (DIAOracleV2) pushes the aggregated off-chain reserves value on-chain when they deviate by 0.5% or every 24 hours, as configured.

3. How to Access Data

3.1. DIAStroomAdapter (Solidity)

The following is the list of available methods on the DIAStroomAdapter contract.

3.1.1. getOnchainReserve()

function getOnchainReserve() public view returns (uint256)

Calculates the total on-chain BTC reserves by aggregating WBTC and cbBTC balances from Stroom converter contract addresses on Ethereum.

Return Value (uint256): The total on-chain BTC reserves in 8 decimals.

3.1.2. getOffchainReserve()

function getOffchainReserve() public view returns (uint256)

Makes a `getValue()` call to the DIA oracle, which in turn aggregates off-chain BTC reserves by querying Lightning API services. The DIA oracle's methodology combines `total_balance` from WalletBalance API with the sum of `local_balance`, `unsettled_local_balance`, and `pending_open_local_balance` from ChannelBalance API.

Return Value (uint256): The total off-chain BTC reserves in 8 decimals.

3.1.3. getCombinedReserveValue()

function getCombinedReserveValue() public view returns (uint256)

Returns the sum of both on-chain and off-chain BTC reserves.

Return Value (uint256): The total combined BTC reserves in 8 decimals.

3.2. Adapter contracts

To consume price data from the oracle, you can use the adapter smart contract for the reserve feed. This will allow you to access the same methods on the `AggregatorV3Interface` such as `latestAnswer` & `latestRoundData`. You can learn more here.

4. Glossary

Term	Definition
Deviation	The percentage threshold that triggers a price update when exceeded
Refresh frequency	A time interval for checking and updating prices if certain conditions are met
Heartbeat	A forced price update at a fixed interval