3.10 Remove use of Network::Bitcoin

All uses were safe due to addresses being converted to script_pubkeys which
don't embed their network. The only risk of there being an issue is if a
future address spec did embed the net ID into the script_pubkey and that was
moved to.

This resolves the audit note and does offer that tightening.

coins/bitcoin/src/wallet/mod.rs

@@ -15,7 +15,8 @@ use frost::{
 use bitcoin::{
   consensus::encode::{Decodable, serialize},
   key::TweakedPublicKey,
-  OutPoint, ScriptBuf, TxOut, Transaction, Block, Network, Address,
+  address::Payload,
+  OutPoint, ScriptBuf, TxOut, Transaction, Block,
 };
 
 use crate::crypto::{x_only, make_even};
@@ -32,15 +33,15 @@ pub fn tweak_keys(keys: &ThresholdKeys<Secp256k1>) -> ThresholdKeys<Secp256k1> {
   keys.offset(Scalar::from(offset))
 }
 
-/// Return the Taproot address for a public key.
+/// Return the Taproot address payload for a public key.
 ///
 /// If the key is odd, this will return None.
-pub fn address(network: Network, key: ProjectivePoint) -> Option<Address> {
+pub fn address_payload(key: ProjectivePoint) -> Option<Payload> {
   if key.to_encoded_point(true).tag() != Tag::CompressedEvenY {
     return None;
   }
 
-  Some(Address::p2tr_tweaked(TweakedPublicKey::dangerous_assume_tweaked(x_only(&key)), network))
+  Some(Payload::p2tr_tweaked(TweakedPublicKey::dangerous_assume_tweaked(x_only(&key))))
 }
 
 /// A spendable output.
@@ -109,8 +110,7 @@ impl Scanner {
   /// Returns None if this key can't be scanned for.
   pub fn new(key: ProjectivePoint) -> Option<Scanner> {
     let mut scripts = HashMap::new();
-    // Uses Network::Bitcoin since network is irrelevant here
-    scripts.insert(address(Network::Bitcoin, key)?.script_pubkey(), Scalar::ZERO);
+    scripts.insert(address_payload(key)?.script_pubkey(), Scalar::ZERO);
     Some(Scanner { key, scripts })
   }
 
@@ -127,7 +127,7 @@ impl Scanner {
     // chance of being even
     // That means this should terminate within a very small amount of iterations
     loop {
-      match address(Network::Bitcoin, self.key + (ProjectivePoint::GENERATOR * offset)) {
+      match address_payload(self.key + (ProjectivePoint::GENERATOR * offset)) {
         Some(address) => {
           let script = address.script_pubkey();
           if self.scripts.contains_key(&script) {

coins/bitcoin/src/wallet/send.rs

@@ -16,12 +16,12 @@ use bitcoin::{
   sighash::{TapSighashType, SighashCache, Prevouts},
   absolute::LockTime,
   script::{PushBytesBuf, ScriptBuf},
-  OutPoint, Sequence, Witness, TxIn, TxOut, Transaction, Network, Address,
+  OutPoint, Sequence, Witness, TxIn, TxOut, Transaction, Address,
 };
 
 use crate::{
   crypto::Schnorr,
-  wallet::{address, ReceivedOutput},
+  wallet::{ReceivedOutput, address_payload},
 };
 
 #[rustfmt::skip]
@@ -226,9 +226,7 @@ impl SignableTransaction {
       transcript.append_message(b"signing_input", u32::try_from(i).unwrap().to_le_bytes());
 
       let offset = keys.clone().offset(self.offsets[i]);
-      if address(Network::Bitcoin, offset.group_key())?.script_pubkey() !=
-        self.prevouts[i].script_pubkey
-      {
+      if address_payload(offset.group_key())?.script_pubkey() != self.prevouts[i].script_pubkey {
         None?;
       }
 

coins/bitcoin/tests/wallet.rs

@@ -22,9 +22,12 @@ use bitcoin_serai::{
     hashes::Hash as HashTrait,
     blockdata::opcodes::all::OP_RETURN,
     script::{PushBytesBuf, Instruction, Instructions, Script},
+    address::NetworkChecked,
     OutPoint, TxOut, Transaction, Network, Address,
   },
-  wallet::{tweak_keys, address, ReceivedOutput, Scanner, TransactionError, SignableTransaction},
+  wallet::{
+    tweak_keys, address_payload, ReceivedOutput, Scanner, TransactionError, SignableTransaction,
+  },
   rpc::Rpc,
 };
 
@@ -43,7 +46,10 @@ async fn send_and_get_output(rpc: &Rpc, scanner: &Scanner, key: ProjectivePoint)
   rpc
     .rpc_call::<Vec<String>>(
       "generatetoaddress",
-      serde_json::json!([1, address(Network::Regtest, key).unwrap()]),
+      serde_json::json!([
+        1,
+        Address::<NetworkChecked>::new(Network::Regtest, address_payload(key).unwrap())
+      ]),
     )
     .await
     .unwrap();
@@ -187,7 +193,7 @@ async_sequential! {
     assert_eq!(output.offset(), Scalar::ZERO);
 
     let inputs = vec![output];
-    let addr = || address(Network::Regtest, key).unwrap();
+    let addr = || Address::<NetworkChecked>::new(Network::Regtest, address_payload(key).unwrap());
     let payments = vec![(addr(), 1000)];
 
     assert!(SignableTransaction::new(inputs.clone(), &payments, None, None, FEE).is_ok());
@@ -250,13 +256,14 @@ async_sequential! {
 
     // Declare payments, change, fee
     let payments = [
-      (address(Network::Regtest, key).unwrap(), 1005),
-      (address(Network::Regtest, offset_key).unwrap(), 1007)
+      (Address::<NetworkChecked>::new(Network::Regtest, address_payload(key).unwrap()), 1005),
+      (Address::<NetworkChecked>::new(Network::Regtest, address_payload(offset_key).unwrap()), 1007)
     ];
 
     let change_offset = scanner.register_offset(Scalar::random(&mut OsRng)).unwrap();
     let change_key = key + (ProjectivePoint::GENERATOR * change_offset);
-    let change_addr = address(Network::Regtest, change_key).unwrap();
+    let change_addr =
+      Address::<NetworkChecked>::new(Network::Regtest, address_payload(change_key).unwrap());
 
     // Create and sign the TX
     let tx = SignableTransaction::new(
@@ -327,7 +334,7 @@ async_sequential! {
       SignableTransaction::new(
         vec![output],
         &[],
-        address(Network::Regtest, key),
+        Some(Address::<NetworkChecked>::new(Network::Regtest, address_payload(key).unwrap())),
         Some(data.clone()),
         FEE
       ).unwrap()