refactor: use bosd::Descriptor for operator reimbursement

.gitignore

@@ -312,3 +312,6 @@ certs
 *.hex
 
 .obsidian
+
+# local regressions
+**/proptest-regressions/*

bin/alpen-bridge/src/rpc_server.rs

@@ -773,25 +773,25 @@ impl StrataBridgeDaApiServer for BridgeRpc {
                     .get(&claim_txid)
                     .map(|sigs| sigs.challenge);
 
-                let reimbursement_key = contract
+                let reimbursement_descriptor = contract
                     .0
                     .state
                     .state
                     .graph_input(claim_txid)
-                    .map(|input| input.operator_pubkey);
+                    .map(|input| input.operator_descriptor.clone());
 
-                match (challenge_sig, reimbursement_key) {
-                    (Some(challenge_sig), Some(reimbursement_key)) => {
-                        Some((challenge_sig, reimbursement_key))
+                match (challenge_sig, reimbursement_descriptor) {
+                    (Some(challenge_sig), Some(reimbursement_descriptor)) => {
+                        Some((challenge_sig, reimbursement_descriptor))
                     }
                     _ => None, // No challenge transaction available for this claim
                 }
             })
-            .map(|(challenge_sig, reimbursement_key)| {
+            .map(|(challenge_sig, operator_descriptor)| {
                 let challenge_input = ChallengeTxInput {
                     claim_outpoint: OutPoint::new(claim_txid, CHALLENGE_VOUT),
                     challenge_amt: self.params.tx_graph.challenge_cost,
-                    operator_pubkey: reimbursement_key,
+                    operator_descriptor,
                     network: self.params.network,
                 };
 
@@ -814,7 +814,6 @@ impl StrataBridgeDaApiServer for BridgeRpc {
                 ChallengeTx::new(challenge_input, challenge_connector)
                     .finalize_presigned(ConnectorC1Path::Challenge(challenge_sig))
             });
-
         Ok(challenge_tx)
     }
 
@@ -854,7 +853,7 @@ impl StrataBridgeDaApiServer for BridgeRpc {
                     deposit_txid: contract.0.deposit_txid,
                     stake_outpoint: OutPoint::new(graph_summary.stake_txid, STAKE_VOUT),
                     stake_hash: graph_input.stake_hash,
-                    operator_pubkey: graph_input.operator_pubkey,
+                    operator_descriptor: graph_input.operator_descriptor.clone(),
                     wots_public_keys: graph_input.wots_public_keys.clone(),
                     n_of_n_sig,
                 })

bin/dev-cli/src/handlers/disprove.rs

@@ -19,6 +19,7 @@ use strata_bridge_connectors::{
 };
 use strata_bridge_primitives::{
     constants::NUM_ASSERT_DATA_TX,
+    types::descriptor_to_x_only_pubkey,
     wots::{self, Groth16Sigs, Wots256Sig},
 };
 use strata_bridge_proof_protocol::BridgeProofPublicOutput;
@@ -100,7 +101,7 @@ pub(crate) async fn handle_disprove(args: cli::DisproveArgs) -> anyhow::Result<(
         post_assert_txid,
         deposit_txid,
         stake_outpoint,
-        operator_pubkey,
+        operator_descriptor,
         stake_hash,
         wots_public_keys,
         n_of_n_sig,
@@ -141,7 +142,9 @@ pub(crate) async fn handle_disprove(args: cli::DisproveArgs) -> anyhow::Result<(
 
     let connector_stake = ConnectorStake::new(
         agg_pubkey,
-        operator_pubkey,
+        descriptor_to_x_only_pubkey(&operator_descriptor).map_err(|e| {
+            anyhow!("could not extract x-only pubkey from operator descriptor: {e}")
+        })?,
         stake_hash,
         params.stake_chain_delta,
         params.network,

crates/connectors/Cargo.toml

@@ -13,6 +13,7 @@ strata-bridge-proof-snark.workspace = true
 ark-serialize.workspace = true
 bincode.workspace = true
 bitcoin.workspace = true
+bitcoin-bosd.workspace = true
 bitcoin-script.workspace = true
 bitvm.workspace = true
 secp256k1.workspace = true

crates/connectors/src/connector_cpfp.rs

@@ -2,52 +2,42 @@
 //!
 //! Reference: <https://bitcoinops.org/en/topics/cpfp/>
 
-use bitcoin::{key::TapTweak, psbt::Input, Address, Network, ScriptBuf};
-use secp256k1::{schnorr, XOnlyPublicKey};
+use bitcoin::{psbt::Input, Network, ScriptBuf};
+use bitcoin_bosd::Descriptor;
+use secp256k1::schnorr;
 use strata_bridge_primitives::scripts::taproot::finalize_input;
 
 /// Connector for adding outputs to a transaction for CPFP.
 ///
 /// It creates a taproot locking script with a public key that is assumed to be tweaked and expects
 /// a schnorr signature to finalize the input.
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone)]
 pub struct ConnectorCpfp {
     /// The bitcoin network for which to generate output addresses.
     network: Network,
 
-    /// The public key used to create the child transaction in CPFP.
-    public_key: XOnlyPublicKey,
+    /// The locking script for the child transaction in CPFP.
+    locking_script: ScriptBuf,
 }
 
 impl ConnectorCpfp {
     /// Constructs a new CPFP connector.
-    pub const fn new(public_key: XOnlyPublicKey, network: Network) -> Self {
+    pub fn new(descriptor: Descriptor, network: Network) -> Self {
+        let locking_script = descriptor.to_script();
         Self {
             network,
-            public_key,
+            locking_script,
         }
     }
 
-    /// Returns the public key used to create the child transaction in CPFP.
-    pub const fn public_key(&self) -> XOnlyPublicKey {
-        self.public_key
-    }
-
     /// Returns the bitcoin network for which to generate output addresses.
     pub const fn network(&self) -> Network {
         self.network
     }
 
-    /// Generates a taproot address for the child transaction.
-    ///
-    /// This taproot address uses a key-spend path with the public key of the connector.
-    pub fn generate_taproot_address(&self) -> bitcoin::Address {
-        Address::p2tr_tweaked(self.public_key.dangerous_assume_tweaked(), self.network)
-    }
-
     /// Generates the locking script for the child transaction.
-    pub fn generate_locking_script(&self) -> ScriptBuf {
-        self.generate_taproot_address().script_pubkey()
+    pub fn locking_script(&self) -> ScriptBuf {
+        self.locking_script.clone()
     }
 
     /// Finalizes the connector using a schnorr signature.
@@ -104,7 +94,7 @@ mod tests {
 
         let keypair = generate_keypair();
         let xonly_pubkey = keypair.x_only_public_key().0;
-        let connector = ConnectorCpfp::new(xonly_pubkey, network);
+        let connector = ConnectorCpfp::new(xonly_pubkey.into(), network);
 
         let output_address =
             Address::p2tr_tweaked(xonly_pubkey.dangerous_assume_tweaked(), network);
@@ -125,7 +115,7 @@ mod tests {
         let starting_tx_ins = create_tx_ins([utxo]);
         let starting_tx_outs = create_tx_outs([
             (
-                connector.generate_taproot_address().script_pubkey(),
+                connector.locking_script(),
                 Amount::from_sat(0), // set amount later
             ),
             (wallet_addr.script_pubkey(), unspent.amount),
@@ -171,7 +161,7 @@ mod tests {
         let parent_tx_outs = vec![TxOut {
             value: signed_starting_tx.output[input_utxo_vout].value, /* same output as input (0
                                                                       * fees) */
-            script_pubkey: connector.generate_taproot_address().script_pubkey(),
+            script_pubkey: connector.locking_script(),
         }];
         let mut parent_tx = create_tx(parent_tx_ins, parent_tx_outs);
         parent_tx.version = Version(3);
@@ -213,7 +203,7 @@ mod tests {
 
         let funding_tx_ins = create_tx_ins([utxo]);
         let funding_tx_outs = create_tx_outs([
-            (connector.generate_taproot_address().script_pubkey(), FEES),
+            (connector.locking_script(), FEES),
             (wallet_addr.script_pubkey(), unspent.amount - FEES - FEES),
         ]);
         let funding_tx = create_tx(funding_tx_ins, funding_tx_outs);

crates/connectors/src/connector_s.rs

@@ -51,12 +51,12 @@ use crate::stake_path::StakeSpendPath;
 /// preimage to the [`ConnectorStake`]. It is required that the preimage be securely derived and
 /// never reused under any circumstances
 // TODO: This should replace the `ConnectorS` struct above.
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone)]
 pub struct ConnectorStake {
     /// The N-of-N aggregated public key for the operator set.
     n_of_n_agg_pubkey: XOnlyPublicKey,
 
-    /// The operator's public key.
+    /// The operator's pubkey.
     operator_pubkey: XOnlyPublicKey,
 
     /// The hash of the `k`th stake preimage.