Extract execution details from driving loop

swap/Cargo.toml

@@ -14,6 +14,7 @@ backoff = { version = "0.2", features = ["tokio"] }
 base64 = "0.12"
 bitcoin = { version = "0.23", features = ["rand", "use-serde"] } # TODO: Upgrade other crates in this repo to use this version.
 bitcoin-harness = { git = "https://github.com/coblox/bitcoin-harness-rs", rev = "3be644cd9512c157d3337a189298b8257ed54d04" }
+conquer-once = "0.3"
 derivative = "2"
 ecdsa_fun = { git = "https://github.com/LLFourn/secp256kfun", rev = "510d48ef6a2b19805f7f5c70c598e5b03f668e7a", features = ["libsecp_compat", "serde", "serialization"] }
 futures = { version = "0.3", default-features = false }

swap/src/alice.rs

@@ -184,7 +184,7 @@ pub async fn swap(
     };
 
     let swap_id = Uuid::new_v4();
-    db.insert_latest_state(swap_id, state::Alice::Handshaken(state3.clone()).into())
+    db.insert_latest_state(swap_id, state::Alice::Negotiated(state3.clone()).into())
         .await?;
 
     info!("Handshake complete, we now have State3 for Alice.");
@@ -280,11 +280,7 @@ pub async fn swap(
 
 pub type Swarm = libp2p::Swarm<Behaviour>;
 
-pub fn new_swarm(
-    listen: Multiaddr,
-    transport: SwapTransport,
-    behaviour: Behaviour,
-) -> Result<Swarm> {
+fn new_swarm(listen: Multiaddr, transport: SwapTransport, behaviour: Behaviour) -> Result<Swarm> {
     use anyhow::Context as _;
 
     let local_peer_id = behaviour.peer_id();

swap/src/alice/execution.rs

@@ -1,36 +1,62 @@
 use crate::{
     alice::{amounts, OutEvent, Swarm},
+    bitcoin, monero,
     network::request_response::AliceToBob,
     SwapAmounts, PUNISH_TIMELOCK, REFUND_TIMELOCK,
 };
-use anyhow::{bail, Result};
+use anyhow::{bail, Context, Result};
+use conquer_once::Lazy;
+use ecdsa_fun::{adaptor::Adaptor, nonce::Deterministic};
+use futures::{
+    future::{select, Either},
+    pin_mut,
+};
 use libp2p::request_response::ResponseChannel;
-use std::sync::Arc;
+use sha2::Sha256;
+use std::{sync::Arc, time::Duration};
+use tokio::time::timeout;
 use xmr_btc::{
     alice,
     alice::{State0, State3},
+    bitcoin::{
+        poll_until_block_height_is_gte, BlockHeight, BroadcastSignedTransaction,
+        EncryptedSignature, GetRawTransaction, TransactionBlockHeight, TxCancel, TxLock, TxRefund,
+        WaitForTransactionFinality, WatchForRawTransaction,
+    },
     cross_curve_dleq,
     monero::Transfer,
 };
 
-// TODO(Franck): Make all methods here idempotent using db
+// For each step, we are giving Bob 10 minutes to act.
+static BOB_TIME_TO_ACT: Lazy<Duration> = Lazy::new(|| Duration::from_secs(10 * 60));
+
+// The maximum we assume we need to wait from the moment the monero transaction
+// is mined to the moment it reaches finality. We set 15 confirmations for now
+// (based on Kraken). 1.5 multiplier in case the blockchain is slower than
+// usually. Average of 2 minutes block time
+static MONERO_MAX_FINALITY_TIME: Lazy<Duration> =
+    Lazy::new(|| Duration::from_secs_f64(15f64 * 1.5 * 2f64 * 60f64));
 
 pub async fn negotiate(
     amounts: SwapAmounts,
-    a: crate::bitcoin::SecretKey,
+    a: bitcoin::SecretKey,
     s_a: cross_curve_dleq::Scalar,
-    v_a: crate::monero::PrivateViewKey,
+    v_a: monero::PrivateViewKey,
     swarm: &mut Swarm,
-    bitcoin_wallet: Arc<crate::bitcoin::Wallet>,
-) -> Result<(ResponseChannel<AliceToBob>, SwapAmounts, State3)> {
-    // Bob dials us
-    match swarm.next().await {
+    bitcoin_wallet: Arc<bitcoin::Wallet>,
+) -> Result<(ResponseChannel<AliceToBob>, State3)> {
+    let event = timeout(*BOB_TIME_TO_ACT, swarm.next())
+        .await
+        .context("Failed to receive dial connection from Bob")?;
+    match event {
         OutEvent::ConnectionEstablished(_bob_peer_id) => {}
         other => bail!("Unexpected event received: {:?}", other),
-    };
+    }
 
-    // Bob sends us a request
-    let (btc, channel) = match swarm.next().await {
+    let event = timeout(*BOB_TIME_TO_ACT, swarm.next())
+        .await
+        .context("Failed to receive amounts from Bob")?;
+    let (btc, channel) = match event {
         OutEvent::Request(amounts::OutEvent::Btc { btc, channel }) => (btc, channel),
         other => bail!("Unexpected event received: {:?}", other),
     };
@@ -42,8 +68,17 @@ pub async fn negotiate(
             amounts.btc
         );
     }
+    // TODO: get an ack from libp2p2
     swarm.send_amounts(channel, amounts);
 
+    let event = timeout(*BOB_TIME_TO_ACT, swarm.next())
+        .await
+        .context("Failed to receive message 0 from Bob")?;
+    let message0 = match event {
+        OutEvent::Message0(msg) => msg,
+        other => bail!("Unexpected event received: {:?}", other),
+    };
+
     let SwapAmounts { btc, xmr } = amounts;
 
     let redeem_address = bitcoin_wallet.as_ref().new_address().await?;
@@ -61,43 +96,67 @@ pub async fn negotiate(
         punish_address,
     );
 
-    // Bob sends us message0
-    let message0 = match swarm.next().await {
-        OutEvent::Message0(msg) => msg,
-        other => bail!("Unexpected event received: {:?}", other),
-    };
-
     let state1 = state0.receive(message0)?;
 
-    let (state2, channel) = match swarm.next().await {
-        OutEvent::Message1 { msg, channel } => {
-            let state2 = state1.receive(msg);
-            (state2, channel)
-        }
+    let event = timeout(*BOB_TIME_TO_ACT, swarm.next())
+        .await
+        .context("Failed to receive message 1 from Bob")?;
+    let (msg, channel) = match event {
+        OutEvent::Message1 { msg, channel } => (msg, channel),
         other => bail!("Unexpected event: {:?}", other),
     };
 
+    let state2 = state1.receive(msg);
+
     let message1 = state2.next_message();
     swarm.send_message1(channel, message1);
 
-    let (state3, channel) = match swarm.next().await {
-        OutEvent::Message2 { msg, channel } => {
-            let state3 = state2.receive(msg)?;
-            (state3, channel)
-        }
+    let event = timeout(*BOB_TIME_TO_ACT, swarm.next())
+        .await
+        .context("Failed to receive message 2 from Bob")?;
+    let (msg, channel) = match event {
+        OutEvent::Message2 { msg, channel } => (msg, channel),
         other => bail!("Unexpected event: {:?}", other),
     };
 
-    Ok((channel, amounts, state3))
+    let state3 = state2.receive(msg)?;
+
+    Ok((channel, state3))
+}
+
+pub async fn wait_for_locked_bitcoin<W>(
+    lock_bitcoin_txid: bitcoin::Txid,
+    bitcoin_wallet: Arc<W>,
+) -> Result<()>
+where
+    W: WatchForRawTransaction + WaitForTransactionFinality,
+{
+    // We assume we will see Bob's transaction in the mempool first.
+    timeout(
+        *BOB_TIME_TO_ACT,
+        bitcoin_wallet.watch_for_raw_transaction(lock_bitcoin_txid),
+    )
+    .await
+    .context("Failed to find lock Bitcoin tx")?;
+
+    // We saw the transaction in the mempool, waiting for it to be confirmed.
+    bitcoin_wallet
+        .wait_for_transaction_finality(lock_bitcoin_txid)
+        .await;
+
+    Ok(())
 }
 
-pub async fn lock_xmr(
+pub async fn lock_xmr<W>(
     channel: ResponseChannel<AliceToBob>,
     amounts: SwapAmounts,
     state3: State3,
     swarm: &mut Swarm,
-    monero_wallet: Arc<crate::monero::Wallet>,
-) -> Result<()> {
+    monero_wallet: Arc<W>,
+) -> Result<()>
+where
+    W: Transfer,
+{
     let S_a = monero::PublicKey::from_private_key(&monero::PrivateKey {
         scalar: state3.s_a.into_ed25519(),
     });
@@ -109,11 +168,206 @@ pub async fn lock_xmr(
         .transfer(public_spend_key, public_view_key, amounts.xmr)
         .await?;
 
+    // TODO(Franck): Wait for Monero to be confirmed once
+
     swarm.send_message2(channel, alice::Message2 {
         tx_lock_proof: transfer_proof,
     });
 
-    // TODO(Franck): Wait for Monero to be mined/finalised
+    Ok(())
+}
+
+pub async fn wait_for_bitcoin_encrypted_signature(swarm: &mut Swarm) -> Result<EncryptedSignature> {
+    let event = timeout(*MONERO_MAX_FINALITY_TIME, swarm.next())
+        .await
+        .context("Failed to receive Bitcoin encrypted signature from Bob")?;
+
+    match event {
+        OutEvent::Message3(msg) => Ok(msg.tx_redeem_encsig),
+        other => bail!(
+            "Expected Bob's Bitcoin redeem encrypted signature, got: {:?}",
+            other
+        ),
+    }
+}
+
+pub fn build_bitcoin_redeem_transaction(
+    encrypted_signature: EncryptedSignature,
+    tx_lock: &TxLock,
+    a: bitcoin::SecretKey,
+    s_a: cross_curve_dleq::Scalar,
+    B: bitcoin::PublicKey,
+    redeem_address: &bitcoin::Address,
+) -> Result<bitcoin::Transaction> {
+    let adaptor = Adaptor::<Sha256, Deterministic<Sha256>>::default();
+
+    let tx_redeem = bitcoin::TxRedeem::new(tx_lock, redeem_address);
+
+    bitcoin::verify_encsig(
+        B.clone(),
+        s_a.into_secp256k1().into(),
+        &tx_redeem.digest(),
+        &encrypted_signature,
+    )
+    .context("Invalid encrypted signature received")?;
+
+    let sig_a = a.sign(tx_redeem.digest());
+    let sig_b = adaptor.decrypt_signature(&s_a.into_secp256k1(), encrypted_signature.clone());
+
+    let tx = tx_redeem
+        .add_signatures(&tx_lock, (a.public(), sig_a), (B.clone(), sig_b))
+        .context("sig_{a,b} are invalid for tx_redeem")?;
+
+    Ok(tx)
+}
+
+pub async fn publish_bitcoin_redeem_transaction<W>(
+    redeem_tx: bitcoin::Transaction,
+    bitcoin_wallet: Arc<W>,
+) -> Result<()>
+where
+    W: BroadcastSignedTransaction + WaitForTransactionFinality,
+{
+    let tx_id = bitcoin_wallet
+        .broadcast_signed_transaction(redeem_tx)
+        .await?;
 
+    // TODO(Franck): Not sure if we wait for finality here or just mined
+    bitcoin_wallet.wait_for_transaction_finality(tx_id).await;
     Ok(())
 }
+
+pub async fn publish_cancel_transaction<W>(
+    tx_lock: TxLock,
+    a: bitcoin::SecretKey,
+    B: bitcoin::PublicKey,
+    refund_timelock: u32,
+    tx_cancel_sig_bob: bitcoin::Signature,
+    bitcoin_wallet: Arc<W>,
+) -> Result<bitcoin::TxCancel>
+where
+    W: GetRawTransaction + TransactionBlockHeight + BlockHeight + BroadcastSignedTransaction,
+{
+    // First wait for t1 to expire
+    let tx_lock_height = bitcoin_wallet
+        .transaction_block_height(tx_lock.txid())
+        .await;
+    poll_until_block_height_is_gte(bitcoin_wallet.as_ref(), tx_lock_height + refund_timelock).await;
+
+    let tx_cancel = bitcoin::TxCancel::new(&tx_lock, refund_timelock, a.public(), B.clone());
+
+    // If Bob hasn't yet broadcasted the tx cancel, we do it
+    if let Err(_) = bitcoin_wallet.get_raw_transaction(tx_cancel.txid()).await {
+        // TODO(Franck): Maybe the cancel transaction is already mined, in this case,
+        // the broadcast will error out.
+
+        let sig_a = a.sign(tx_cancel.digest());
+        let sig_b = tx_cancel_sig_bob.clone();
+
+        let tx_cancel = tx_cancel
+            .clone()
+            .add_signatures(&tx_lock, (a.public(), sig_a), (B.clone(), sig_b))
+            .expect("sig_{a,b} to be valid signatures for tx_cancel");
+
+        // TODO(Franck): Error handling is delicate, why can't we broadcast?
+        bitcoin_wallet
+            .broadcast_signed_transaction(tx_cancel)
+            .await?;
+
+        // TODO(Franck): Wait until transaction is mined and returned mined
+        // block height
+    }
+
+    Ok(tx_cancel)
+}
+
+pub async fn wait_for_bitcoin_refund<W>(
+    tx_cancel: &TxCancel,
+    cancel_tx_height: u32,
+    punish_timelock: u32,
+    refund_address: &bitcoin::Address,
+    bitcoin_wallet: Arc<W>,
+) -> Result<(bitcoin::TxRefund, Option<bitcoin::Transaction>)>
+where
+    W: BlockHeight + WatchForRawTransaction,
+{
+    let punish_timelock_expired =
+        poll_until_block_height_is_gte(bitcoin_wallet.as_ref(), cancel_tx_height + punish_timelock);
+
+    let tx_refund = bitcoin::TxRefund::new(tx_cancel, refund_address);
+
+    // TODO(Franck): This only checks the mempool, need to cater for the case where
+    // the transaction goes directly in a block
+    let seen_refund_tx = bitcoin_wallet.watch_for_raw_transaction(tx_refund.txid());
+
+    pin_mut!(punish_timelock_expired);
+    pin_mut!(seen_refund_tx);
+
+    match select(punish_timelock_expired, seen_refund_tx).await {
+        Either::Left(_) => Ok((tx_refund, None)),
+        Either::Right((published_refund_tx, _)) => Ok((tx_refund, Some(published_refund_tx))),
+    }
+}
+
+pub fn extract_monero_private_key(
+    published_refund_tx: bitcoin::Transaction,
+    tx_refund: TxRefund,
+    s_a: cross_curve_dleq::Scalar,
+    a: bitcoin::SecretKey,
+    S_b_bitcoin: bitcoin::PublicKey,
+) -> Result<monero::PrivateKey> {
+    let s_a = monero::PrivateKey {
+        scalar: s_a.into_ed25519(),
+    };
+
+    let tx_refund_sig = tx_refund
+        .extract_signature_by_key(published_refund_tx, a.public())
+        .context("Failed to extract signature from Bitcoin refund tx")?;
+    let tx_refund_encsig = a.encsign(S_b_bitcoin.clone(), tx_refund.digest());
+
+    let s_b = bitcoin::recover(S_b_bitcoin, tx_refund_sig, tx_refund_encsig)
+        .context("Failed to recover Monero secret key from Bitcoin signature")?;
+    let s_b = monero::private_key_from_secp256k1_scalar(s_b.into());
+
+    let spend_key = s_a + s_b;
+
+    Ok(spend_key)
+}
+
+pub fn build_bitcoin_punish_transaction(
+    tx_lock: &TxLock,
+    refund_timelock: u32,
+    punish_address: &bitcoin::Address,
+    punish_timelock: u32,
+    tx_punish_sig_bob: bitcoin::Signature,
+    a: bitcoin::SecretKey,
+    B: bitcoin::PublicKey,
+) -> Result<bitcoin::Transaction> {
+    let tx_cancel = bitcoin::TxCancel::new(&tx_lock, refund_timelock, a.public(), B.clone());
+    let tx_punish = bitcoin::TxPunish::new(&tx_cancel, &punish_address, punish_timelock);
+
+    let sig_a = a.sign(tx_punish.digest());
+    let sig_b = tx_punish_sig_bob.clone();
+
+    let signed_tx_punish = tx_punish
+        .add_signatures(&tx_cancel, (a.public(), sig_a), (B.clone(), sig_b))
+        .expect("sig_{a,b} to be valid signatures for tx_cancel");
+
+    Ok(signed_tx_punish)
+}
+
+pub async fn publish_bitcoin_punish_transaction<W>(
+    punish_tx: bitcoin::Transaction,
+    bitcoin_wallet: Arc<W>,
+) -> Result<bitcoin::Txid>
+where
+    W: BroadcastSignedTransaction + WaitForTransactionFinality,
+{
+    let txid = bitcoin_wallet
+        .broadcast_signed_transaction(punish_tx)
+        .await?;
+
+    bitcoin_wallet.wait_for_transaction_finality(txid).await;
+
+    Ok(txid)
+}

swap/src/alice/swap.rs

@@ -2,35 +2,32 @@
 //! Alice holds XMR and wishes receive BTC.
 use crate::{
     alice::{
-        execution::{lock_xmr, negotiate},
-        OutEvent, Swarm,
+        execution::{
+            build_bitcoin_punish_transaction, build_bitcoin_redeem_transaction,
+            extract_monero_private_key, lock_xmr, negotiate, publish_bitcoin_punish_transaction,
+            publish_bitcoin_redeem_transaction, publish_cancel_transaction,
+            wait_for_bitcoin_encrypted_signature, wait_for_bitcoin_refund, wait_for_locked_bitcoin,
+        },
+        Swarm,
     },
     bitcoin,
-    bitcoin::{EncryptedSignature, TX_LOCK_MINE_TIMEOUT},
+    bitcoin::EncryptedSignature,
     monero,
     network::request_response::AliceToBob,
     SwapAmounts,
 };
-use anyhow::{anyhow, Context, Result};
+use anyhow::Result;
 use async_recursion::async_recursion;
-use ecdsa_fun::{adaptor::Adaptor, nonce::Deterministic};
 use futures::{
     future::{select, Either},
     pin_mut,
 };
 use libp2p::request_response::ResponseChannel;
 use rand::{CryptoRng, RngCore};
-use sha2::Sha256;
-use std::{sync::Arc, time::Duration};
-use tokio::time::timeout;
-
+use std::sync::Arc;
 use xmr_btc::{
     alice::State3,
-    bitcoin::{
-        poll_until_block_height_is_gte, BroadcastSignedTransaction, GetRawTransaction,
-        TransactionBlockHeight, TxCancel, TxRefund, WaitForTransactionFinality,
-        WatchForRawTransaction,
-    },
+    bitcoin::{TransactionBlockHeight, TxCancel, TxRefund, WatchForRawTransaction},
     cross_curve_dleq,
     monero::CreateWalletForOutput,
 };
@@ -79,11 +76,6 @@ pub enum AliceState {
         tx_refund: TxRefund,
         state3: State3,
     },
-    BtcPunished {
-        tx_refund: TxRefund,
-        punished_tx_id: bitcoin::Txid,
-        state3: State3,
-    },
     XmrRefunded,
     WaitingToCancel {
         state3: State3,
@@ -107,7 +99,7 @@ pub async fn swap(
             s_a,
             v_a,
         } => {
-            let (channel, amounts, state3) =
+            let (channel, state3) =
                 negotiate(amounts, a, s_a, v_a, &mut swarm, bitcoin_wallet.clone()).await?;
 
             swap(
@@ -127,12 +119,7 @@ pub async fn swap(
             channel,
             amounts,
         } => {
-            timeout(
-                Duration::from_secs(TX_LOCK_MINE_TIMEOUT),
-                bitcoin_wallet.wait_for_transaction_finality(state3.tx_lock.txid()),
-            )
-            .await
-            .context("Timed out, Bob did not lock Bitcoin in time")?;
+            let _ = wait_for_locked_bitcoin(state3.tx_lock.txid(), bitcoin_wallet.clone()).await?;
 
             swap(
                 AliceState::BtcLocked {
@@ -169,37 +156,22 @@ pub async fn swap(
             .await
         }
         AliceState::XmrLocked { state3 } => {
-            let encsig = timeout(
-                // Give a set arbitrary time to Bob to send us `tx_redeem_encsign`
-                Duration::from_secs(TX_LOCK_MINE_TIMEOUT),
-                async {
-                    match swarm.next().await {
-                        OutEvent::Message3(msg) => Ok(msg.tx_redeem_encsig),
-                        other => Err(anyhow!(
-                            "Expected Bob's Bitcoin redeem encsig, got: {:?}",
-                            other
-                        )),
-                    }
-                },
-            )
-            .await
-            .context("Timed out, Bob did not send redeem encsign in time");
-
-            match encsig {
-                Err(_timeout_error) => {
-                    // TODO(Franck): Insert in DB
-
+            // Our Monero is locked, we need to go through the cancellation process if this
+            // step fails
+            match wait_for_bitcoin_encrypted_signature(&mut swarm).await {
+                Ok(encrypted_signature) => {
                     swap(
-                        AliceState::WaitingToCancel { state3 },
+                        AliceState::EncSignLearned {
+                            state3,
+                            encrypted_signature,
+                        },
                         swarm,
                         bitcoin_wallet,
                         monero_wallet,
                     )
                     .await
                 }
-                Ok(Err(_unexpected_msg_error)) => {
-                    // TODO(Franck): Insert in DB
-
+                Err(_) => {
                     swap(
                         AliceState::WaitingToCancel { state3 },
                         swarm,
@@ -208,62 +180,36 @@ pub async fn swap(
                     )
                     .await
                 }
-                Ok(Ok(encrypted_signature)) => {
-                    // TODO(Franck): Insert in DB
-
-                    swap(
-                        AliceState::EncSignLearned {
-                            state3,
-                            encrypted_signature,
-                        },
-                        swarm,
-                        bitcoin_wallet,
-                        monero_wallet,
-                    )
-                    .await
-                }
             }
         }
         AliceState::EncSignLearned {
             state3,
             encrypted_signature,
         } => {
-            let (signed_tx_redeem, _tx_redeem_txid) = {
-                let adaptor = Adaptor::<Sha256, Deterministic<Sha256>>::default();
-
-                let tx_redeem = bitcoin::TxRedeem::new(&state3.tx_lock, &state3.redeem_address);
-
-                bitcoin::verify_encsig(
-                    state3.B.clone(),
-                    state3.s_a.into_secp256k1().into(),
-                    &tx_redeem.digest(),
-                    &encrypted_signature,
-                )
-                .context("Invalid encrypted signature received")?;
-
-                let sig_a = state3.a.sign(tx_redeem.digest());
-                let sig_b = adaptor
-                    .decrypt_signature(&state3.s_a.into_secp256k1(), encrypted_signature.clone());
-
-                let tx = tx_redeem
-                    .add_signatures(
-                        &state3.tx_lock,
-                        (state3.a.public(), sig_a),
-                        (state3.B.clone(), sig_b),
+            let signed_tx_redeem = match build_bitcoin_redeem_transaction(
+                encrypted_signature,
+                &state3.tx_lock,
+                state3.a.clone(),
+                state3.s_a,
+                state3.B.clone(),
+                &state3.redeem_address,
+            ) {
+                Ok(tx) => tx,
+                Err(_) => {
+                    return swap(
+                        AliceState::WaitingToCancel { state3 },
+                        swarm,
+                        bitcoin_wallet,
+                        monero_wallet,
                     )
-                    .expect("sig_{a,b} to be valid signatures for tx_redeem");
-                let txid = tx.txid();
-
-                (tx, txid)
+                    .await;
+                }
             };
 
-            // TODO(Franck): Insert in db
-
-            let _ = bitcoin_wallet
-                .broadcast_signed_transaction(signed_tx_redeem)
-                .await?;
-
-            // TODO(Franck) Wait for confirmations
+            // TODO(Franck): Error handling is delicate here.
+            // If Bob sees this transaction he can redeem Monero
+            // e.g. If the Bitcoin node is down then the user needs to take action.
+            publish_bitcoin_redeem_transaction(signed_tx_redeem, bitcoin_wallet.clone()).await?;
 
             swap(
                 AliceState::BtcRedeemed,
@@ -274,39 +220,15 @@ pub async fn swap(
             .await
         }
         AliceState::WaitingToCancel { state3 } => {
-            let tx_lock_height = bitcoin_wallet
-                .transaction_block_height(state3.tx_lock.txid())
-                .await;
-            poll_until_block_height_is_gte(
-                bitcoin_wallet.as_ref(),
-                tx_lock_height + state3.refund_timelock,
-            )
-            .await;
-
-            let tx_cancel = bitcoin::TxCancel::new(
-                &state3.tx_lock,
-                state3.refund_timelock,
-                state3.a.public(),
+            let tx_cancel = publish_cancel_transaction(
+                state3.tx_lock.clone(),
+                state3.a.clone(),
                 state3.B.clone(),
-            );
-
-            if let Err(_e) = bitcoin_wallet.get_raw_transaction(tx_cancel.txid()).await {
-                let sig_a = state3.a.sign(tx_cancel.digest());
-                let sig_b = state3.tx_cancel_sig_bob.clone();
-
-                let tx_cancel = tx_cancel
-                    .clone()
-                    .add_signatures(
-                        &state3.tx_lock,
-                        (state3.a.public(), sig_a),
-                        (state3.B.clone(), sig_b),
-                    )
-                    .expect("sig_{a,b} to be valid signatures for tx_cancel");
-
-                bitcoin_wallet
-                    .broadcast_signed_transaction(tx_cancel)
-                    .await?;
-            }
+                state3.refund_timelock,
+                state3.tx_cancel_sig_bob.clone(),
+                bitcoin_wallet.clone(),
+            )
+            .await?;
 
             swap(
                 AliceState::BtcCancelled { state3, tx_cancel },
@@ -321,19 +243,18 @@ pub async fn swap(
                 .transaction_block_height(tx_cancel.txid())
                 .await;
 
-            let reached_t2 = poll_until_block_height_is_gte(
-                bitcoin_wallet.as_ref(),
-                tx_cancel_height + state3.punish_timelock,
-            );
-
-            let tx_refund = bitcoin::TxRefund::new(&tx_cancel, &state3.refund_address);
-            let seen_refund_tx = bitcoin_wallet.watch_for_raw_transaction(tx_refund.txid());
-
-            pin_mut!(reached_t2);
-            pin_mut!(seen_refund_tx);
+            let (tx_refund, published_refund_tx) = wait_for_bitcoin_refund(
+                &tx_cancel,
+                tx_cancel_height,
+                state3.punish_timelock,
+                &state3.refund_address,
+                bitcoin_wallet.clone(),
+            )
+            .await?;
 
-            match select(reached_t2, seen_refund_tx).await {
-                Either::Left(_) => {
+            // TODO(Franck): Review error handling
+            match published_refund_tx {
+                None => {
                     swap(
                         AliceState::BtcPunishable { tx_refund, state3 },
                         swarm,
@@ -342,7 +263,7 @@ pub async fn swap(
                     )
                     .await
                 }
-                Either::Right((published_refund_tx, _)) => {
+                Some(published_refund_tx) => {
                     swap(
                         AliceState::BtcRefunded {
                             tx_refund,
@@ -362,22 +283,13 @@ pub async fn swap(
             published_refund_tx,
             state3,
         } => {
-            let s_a = monero::PrivateKey {
-                scalar: state3.s_a.into_ed25519(),
-            };
-
-            let tx_refund_sig = tx_refund
-                .extract_signature_by_key(published_refund_tx, state3.a.public())
-                .context("Failed to extract signature from Bitcoin refund tx")?;
-            let tx_refund_encsig = state3
-                .a
-                .encsign(state3.S_b_bitcoin.clone(), tx_refund.digest());
-
-            let s_b = bitcoin::recover(state3.S_b_bitcoin, tx_refund_sig, tx_refund_encsig)
-                .context("Failed to recover Monero secret key from Bitcoin signature")?;
-            let s_b = monero::private_key_from_secp256k1_scalar(s_b.into());
-
-            let spend_key = s_a + s_b;
+            let spend_key = extract_monero_private_key(
+                published_refund_tx,
+                tx_refund,
+                state3.s_a,
+                state3.a.clone(),
+                state3.S_b_bitcoin,
+            )?;
             let view_key = state3.v;
 
             monero_wallet
@@ -387,49 +299,18 @@ pub async fn swap(
             Ok(AliceState::XmrRefunded)
         }
         AliceState::BtcPunishable { tx_refund, state3 } => {
-            let tx_cancel = bitcoin::TxCancel::new(
+            let signed_tx_punish = build_bitcoin_punish_transaction(
                 &state3.tx_lock,
                 state3.refund_timelock,
-                state3.a.public(),
+                &state3.punish_address,
+                state3.punish_timelock,
+                state3.tx_punish_sig_bob.clone(),
+                state3.a.clone(),
                 state3.B.clone(),
-            );
-            let tx_punish =
-                bitcoin::TxPunish::new(&tx_cancel, &state3.punish_address, state3.punish_timelock);
-            let punished_tx_id = tx_punish.txid();
-
-            let sig_a = state3.a.sign(tx_punish.digest());
-            let sig_b = state3.tx_punish_sig_bob.clone();
+            )?;
 
-            let signed_tx_punish = tx_punish
-                .add_signatures(
-                    &tx_cancel,
-                    (state3.a.public(), sig_a),
-                    (state3.B.clone(), sig_b),
-                )
-                .expect("sig_{a,b} to be valid signatures for tx_cancel");
-
-            let _ = bitcoin_wallet
-                .broadcast_signed_transaction(signed_tx_punish)
-                .await?;
-
-            swap(
-                AliceState::BtcPunished {
-                    tx_refund,
-                    punished_tx_id,
-                    state3,
-                },
-                swarm,
-                bitcoin_wallet.clone(),
-                monero_wallet,
-            )
-            .await
-        }
-        AliceState::BtcPunished {
-            punished_tx_id,
-            tx_refund,
-            state3,
-        } => {
-            let punish_tx_finalised = bitcoin_wallet.wait_for_transaction_finality(punished_tx_id);
+            let punish_tx_finalised =
+                publish_bitcoin_punish_transaction(signed_tx_punish, bitcoin_wallet.clone());
 
             let refund_tx_seen = bitcoin_wallet.watch_for_raw_transaction(tx_refund.txid());
 
@@ -461,7 +342,6 @@ pub async fn swap(
                 }
             }
         }
-
         AliceState::XmrRefunded => Ok(AliceState::XmrRefunded),
         AliceState::BtcRedeemed => Ok(AliceState::BtcRedeemed),
         AliceState::Punished => Ok(AliceState::Punished),

swap/src/bitcoin.rs

@@ -3,15 +3,15 @@ use std::time::Duration;
 use anyhow::Result;
 use async_trait::async_trait;
 use backoff::{backoff::Constant as ConstantBackoff, future::FutureOperation as _};
-use bitcoin::{util::psbt::PartiallySignedTransaction, Address, Transaction};
+use bitcoin::util::psbt::PartiallySignedTransaction;
 use bitcoin_harness::bitcoind_rpc::PsbtBase64;
 use reqwest::Url;
-use tokio::time;
 use xmr_btc::bitcoin::{
     BlockHeight, BroadcastSignedTransaction, BuildTxLockPsbt, SignTxLock, TransactionBlockHeight,
     WatchForRawTransaction,
 };
 
+pub use ::bitcoin::{Address, Transaction};
 pub use xmr_btc::bitcoin::*;
 
 pub const TX_LOCK_MINE_TIMEOUT: u64 = 3600;
@@ -85,15 +85,7 @@ impl SignTxLock for Wallet {
 #[async_trait]
 impl BroadcastSignedTransaction for Wallet {
     async fn broadcast_signed_transaction(&self, transaction: Transaction) -> Result<Txid> {
-        let txid = self.0.send_raw_transaction(transaction).await?;
-
-        // TODO: Instead of guessing how long it will take for the transaction to be
-        // mined we should ask bitcoind for the number of confirmations on `txid`
-
-        // give time for transaction to be mined
-        time::delay_for(Duration::from_millis(1100)).await;
-
-        Ok(txid)
+        Ok(self.0.send_raw_transaction(transaction).await?)
     }
 }
 

swap/src/bob/execution.rs

@@ -1,13 +1,13 @@
 use crate::{
     bob::{OutEvent, Swarm},
-    Cmd, Rsp, SwapAmounts, PUNISH_TIMELOCK, REFUND_TIMELOCK,
+    Cmd, Rsp, SwapAmounts,
 };
 use anyhow::Result;
 use rand::{CryptoRng, RngCore};
 use std::sync::Arc;
 use tokio::{stream::StreamExt, sync::mpsc};
 
-use xmr_btc::bob::{State0, State2};
+use xmr_btc::bob::State2;
 
 pub async fn negotiate<R>(
     state0: xmr_btc::bob::State0,

swap/src/recover.rs

@@ -45,7 +45,7 @@ pub async fn alice_recover(
     state: Alice,
 ) -> Result<()> {
     match state {
-        Alice::Handshaken(_) | Alice::BtcLocked(_) | Alice::SwapComplete => {
+        Alice::Negotiated(_) | Alice::BtcLocked(_) | Alice::SwapComplete => {
             info!("Nothing to do");
         }
         Alice::XmrLocked(state) => {

swap/src/state.rs

@@ -12,7 +12,7 @@ pub enum Swap {
 #[allow(clippy::large_enum_variant)]
 #[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
 pub enum Alice {
-    Handshaken(alice::State3),
+    Negotiated(alice::State3),
     BtcLocked(alice::State3),
     XmrLocked(alice::State3),
     BtcRedeemable {
@@ -63,7 +63,7 @@ impl Display for Swap {
 impl Display for Alice {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
-            Alice::Handshaken(_) => f.write_str("Handshake complete"),
+            Alice::Negotiated(_) => f.write_str("Handshake complete"),
             Alice::BtcLocked(_) => f.write_str("Bitcoin locked"),
             Alice::XmrLocked(_) => f.write_str("Monero locked"),
             Alice::BtcRedeemable { .. } => f.write_str("Bitcoin redeemable"),

swap/tests/e2e.rs

@@ -1,11 +1,5 @@
 use bitcoin_harness::Bitcoind;
-use futures::{
-    channel::{
-        mpsc,
-        mpsc::{Receiver, Sender},
-    },
-    future::try_join,
-};
+use futures::{channel::mpsc, future::try_join};
 use libp2p::Multiaddr;
 use monero_harness::Monero;
 use rand::rngs::OsRng;

xmr-btc/tests/harness/mod.rs

@@ -160,15 +160,23 @@ pub async fn init_test(
     let punish_address = redeem_address.clone();
     let refund_address = bob.bitcoin_wallet.new_address().await.unwrap();
 
-    let alice_state0 = xmr_btc::alice::State0::new(
-        &mut OsRng,
-        btc_amount,
-        xmr_amount,
-        refund_timelock.unwrap_or(RELATIVE_REFUND_TIMELOCK),
-        punish_timelock.unwrap_or(RELATIVE_PUNISH_TIMELOCK),
-        redeem_address.clone(),
-        punish_address.clone(),
-    );
+    let alice_state0 = {
+        let a = bitcoin::SecretKey::new_random(&mut OsRng);
+        let s_a = cross_curve_dleq::Scalar::random(&mut OsRng);
+        let v_a = monero::PrivateViewKey::new_random(&mut OsRng);
+
+        xmr_btc::alice::State0::new(
+            a,
+            s_a,
+            v_a,
+            btc_amount,
+            xmr_amount,
+            refund_timelock.unwrap_or(RELATIVE_REFUND_TIMELOCK),
+            punish_timelock.unwrap_or(RELATIVE_PUNISH_TIMELOCK),
+            redeem_address.clone(),
+            punish_address.clone(),
+        )
+    };
     let bob_state0 = xmr_btc::bob::State0::new(
         &mut OsRng,
         btc_amount,