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Spark Runes Bridge

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What it supports

• Runes -> Spark: mint wRunes after a BTC deposit is confirmed.
• Spark -> Runes: burn wRunes and build a BTC payout.
• Unique deposit addresses per user + rune + nonce.
• FROST threshold signing across verifiers (M=3).
• 1 BTC confirmation before minting.
• Amounts are strings (u64) to preserve precision.

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Key components

• Gateway: Orchestrates both directions, derives deposit/exit addresses, and builds payout transactions.
• Verifiers: Validate deposits and co-sign mint/burn via threshold signatures.
• BTC indexer: Watches deposits until 1 confirmation.
• Spark balance checker: Confirms wRune funding on Spark deposits.
• Spark entity: Executes Spark-side transactions.

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How it works (high level)

1. Gateway derives a multisig for (user_pubkey, rune_id), tweaks it with a random nonce, and returns a unique deposit_btc_address.
2. User deposits runes and reports { txid, vout }.
3. Verifiers confirm via the BTC indexer, then the gateway mints wRunes using the issuer multisig; tokens land on the Spark address tied to the user.

1. Gateway returns a unique exit_spark_address derived/tweaked from the same key pair.
2. User deposits wRunes; verifiers confirm Spark balance and the gateway signs a burn with the issuer multisig.
3. Gateway assembles a BTC rune payout to the user; any change goes to a fresh deposit address derived from the same key.

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SDK entry point

const runes = bridge.spark.runes;

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Next steps

• Quickstart: bridge/spark-runes/quickstart
• Architecture: bridge/spark-runes/architecture
• API reference: bridge/spark-runes/api