Operator BitVM assert tx Winternitz public key generation (#379)

* operator: Add get_winternitz_public_keys.

* operator: Remove watchtower index in get_winternitz_public_keys.

* operator: Update test_utls function in test.

core/src/actor.rs

@@ -18,6 +18,7 @@ use bitvm::signatures::winternitz::{
 pub enum TxType {
     TimeTx,
     KickoffTx,
+    BitVM,
 }
 
 /// Derivation path specification for Winternitz one time public key generation.

core/src/operator.rs

@@ -1,4 +1,4 @@
-use crate::actor::Actor;
+use crate::actor::{Actor, WinternitzDerivationPath};
 use crate::builder::transaction::KICKOFF_UTXO_AMOUNT_SATS;
 use crate::builder::{self};
 use crate::config::BridgeConfig;
@@ -15,6 +15,7 @@ use bitcoin::script::PushBytesBuf;
 use bitcoin::sighash::SighashCache;
 use bitcoin::{Address, Amount, OutPoint, TapSighash, Transaction, TxOut, Txid};
 use bitcoincore_rpc::{RawTx, RpcApi};
+use bitvm::signatures::winternitz;
 use jsonrpsee::core::client::ClientT;
 use jsonrpsee::http_client::HttpClientBuilder;
 use jsonrpsee::rpc_params;
@@ -695,6 +696,33 @@ impl Operator {
 
         Ok(txs_to_be_sent)
     }
+
+    /// Generates Winternitz public keys for every watchtower challenge and
+    /// BitVM assert tx.
+    ///
+    /// # Returns
+    ///
+    /// - [`Vec<Vec<winternitz::PublicKey>>`]: Winternitz public keys for
+    ///   `watchtower index` row and `BitVM assert tx index` column.
+    pub fn get_winternitz_public_keys(&self) -> Result<Vec<winternitz::PublicKey>, BridgeError> {
+        let mut winternitz_pubkeys = Vec::new();
+
+        for time_tx in 0..self.config.num_time_txs as u32 {
+            let path = WinternitzDerivationPath {
+                message_length: 480,
+                log_d: 4,
+                tx_type: crate::actor::TxType::BitVM,
+                index: Some(self.idx as u32),
+                operator_idx: None,
+                watchtower_idx: None,
+                time_tx_idx: Some(time_tx),
+            };
+
+            winternitz_pubkeys.push(self.signer.derive_winternitz_pk(path)?);
+        }
+
+        Ok(winternitz_pubkeys)
+    }
 }
 
 #[cfg(test)]
@@ -776,4 +804,20 @@ mod tests {
             config.operator_withdrawal_fee_sats.unwrap() - Amount::from_sat(1)
         ));
     }
+
+    #[tokio::test]
+    async fn get_winternitz_public_keys() {
+        let config = create_test_config_with_thread_name!(None);
+        let rpc = ExtendedRpc::new(
+            config.bitcoin_rpc_url.clone(),
+            config.bitcoin_rpc_user.clone(),
+            config.bitcoin_rpc_password.clone(),
+        )
+        .await;
+
+        let operator = Operator::new(config.clone(), rpc).await.unwrap();
+
+        let winternitz_public_key = operator.get_winternitz_public_keys().unwrap();
+        assert_eq!(winternitz_public_key.len(), config.num_time_txs);
+    }
 }

core/src/rpc/operator.rs

@@ -1,7 +1,7 @@
 use super::clementine::{
     self, clementine_operator_server::ClementineOperator, DepositSignSession, Empty,
     NewWithdrawalSigParams, NewWithdrawalSigResponse, OperatorBurnSig, OperatorParams,
-    WithdrawalFinalizedParams,
+    WinternitzPubkey, WithdrawalFinalizedParams,
 };
 use crate::{builder, errors::BridgeError, operator::Operator};
 use bitcoin::{hashes::Hash, Amount, OutPoint};
@@ -52,9 +52,16 @@ impl ClementineOperator for Operator {
             .collect()
             .await;
 
+        // Generate Winternitz public keys and convert them to RPC type.
+        let winternitz_pubkeys = self.get_winternitz_public_keys()?;
+        let winternitz_pubkeys = winternitz_pubkeys
+            .into_iter()
+            .map(WinternitzPubkey::from_bitvm)
+            .collect::<Vec<_>>();
+
         let operator_params = clementine::OperatorParams {
             operator_details: Some(operator_config),
-            winternitz_pubkeys: vec![],      // TODO: Implement this.
+            winternitz_pubkeys,
             assert_empty_public_key: vec![], // TODO: Implement this.
             timeout_tx_sigs,
         };

core/src/test_utils.rs

@@ -9,8 +9,6 @@
 ///
 /// # Parameters
 ///
-/// - `config_file`: Test configuration file in `str` type. Rest of the config
-///   will be read from here and only `db_name` will be overwritten.
 /// - `suffix`: Optional suffix added to the thread handle in `Option<str>`
 ///   type.
 ///