Merge rust-bitcoin/rust-bitcoin#681: Add support for taproot psbt fields BIP 371

7d982fa Add all tests from BIP 371 (sanket1729)
d22e014 Taproot psbt impl BIP 371 (sanket1729)
108fc3d Impl encodable traits for TapLeafhash (sanket1729)
c7478d8 Derive serde for taproot stuctures (sanket1729)

Pull request description:

  Built on top of #677 . Will rebase and mark ready for review after #677 is merged.

ACKs for top commit:
  apoelstra:
    ACK 7d982fa
  dr-orlovsky:
    re-tACK 7d982fa basing on `git range-diff`. The original PR before last re-base was tested commit-by-commit.

Tree-SHA512: feb30e4b38d13110a9c0fabf6466d8f0fb7df09a82f4e01d70b8371b34ab0187004a6c63f9796c6585ee30841e8ee765ae9becae139d2e1e3d839553d64c3d1e

Author: dr-orlovsky

src/consensus/encode.rs

@@ -39,6 +39,7 @@ use io::{self, Cursor, Read};
 
 use util::endian;
 use util::psbt;
+use util::taproot::TapLeafHash;
 use hashes::hex::ToHex;
 
 use blockdata::transaction::{TxOut, Transaction, TxIn};
@@ -594,6 +595,7 @@ impl_vec!(TxOut);
 impl_vec!(TxIn);
 impl_vec!(Vec<u8>);
 impl_vec!(u64);
+impl_vec!(TapLeafHash);
 
 #[cfg(feature = "std")] impl_vec!(Inventory);
 #[cfg(feature = "std")] impl_vec!((u32, Address));
@@ -767,6 +769,18 @@ impl Decodable for sha256::Hash {
     }
 }
 
+impl Encodable for TapLeafHash {
+    fn consensus_encode<S: io::Write>(&self, s: S) -> Result<usize, io::Error> {
+        self.into_inner().consensus_encode(s)
+    }
+}
+
+impl Decodable for TapLeafHash {
+    fn consensus_decode<D: io::Read>(d: D) -> Result<Self, Error> {
+        Ok(Self::from_inner(<<Self as Hash>::Inner>::consensus_decode(d)?))
+    }
+}
+
 // Tests
 #[cfg(test)]
 mod tests {

src/util/psbt/map/input.rs

@@ -28,6 +28,9 @@ use util::psbt::raw;
 use util::psbt::serialize::Deserialize;
 use util::psbt::{Error, error};
 
+use schnorr;
+use util::taproot::{ControlBlock, LeafVersion, TapLeafHash, TapBranchHash};
+
 /// Type: Non-Witness UTXO PSBT_IN_NON_WITNESS_UTXO = 0x00
 const PSBT_IN_NON_WITNESS_UTXO: u8 = 0x00;
 /// Type: Witness UTXO PSBT_IN_WITNESS_UTXO = 0x01
@@ -54,6 +57,18 @@ const PSBT_IN_SHA256: u8 = 0x0b;
 const PSBT_IN_HASH160: u8 = 0x0c;
 /// Type: HASH256 preimage PSBT_IN_HASH256 = 0x0d
 const PSBT_IN_HASH256: u8 = 0x0d;
+/// Type: Schnorr Signature in Key Spend PSBT_IN_TAP_KEY_SIG = 0x13
+const PSBT_IN_TAP_KEY_SIG: u8 = 0x13;
+/// Type: Schnorr Signature in Script Spend PSBT_IN_TAP_SCRIPT_SIG = 0x14
+const PSBT_IN_TAP_SCRIPT_SIG: u8 = 0x14;
+/// Type: Taproot Leaf Script PSBT_IN_TAP_LEAF_SCRIPT = 0x14
+const PSBT_IN_TAP_LEAF_SCRIPT: u8 = 0x15;
+/// Type: Taproot Key BIP 32 Derivation Path PSBT_IN_TAP_BIP32_DERIVATION = 0x16
+const PSBT_IN_TAP_BIP32_DERIVATION : u8 = 0x16;
+/// Type: Taproot Internal Key PSBT_IN_TAP_INTERNAL_KEY = 0x17
+const PSBT_IN_TAP_INTERNAL_KEY : u8 = 0x17;
+/// Type: Taproot Merkle Root PSBT_IN_TAP_MERKLE_ROOT = 0x18
+const PSBT_IN_TAP_MERKLE_ROOT : u8 = 0x18;
 /// Type: Proprietary Use Type PSBT_IN_PROPRIETARY = 0xFC
 const PSBT_IN_PROPRIETARY: u8 = 0xFC;
 
@@ -104,6 +119,21 @@ pub struct Input {
     /// HAS256 hash to preimage map
     #[cfg_attr(feature = "serde", serde(with = "::serde_utils::btreemap_byte_values"))]
     pub hash256_preimages: BTreeMap<sha256d::Hash, Vec<u8>>,
+    /// Serialized schnorr signature with sighash type for key spend
+    pub tap_key_sig: Option<schnorr::SchnorrSig>,
+    /// Map of <xonlypubkey>|<leafhash> with signature
+    #[cfg_attr(feature = "serde", serde(with = "::serde_utils::btreemap_as_seq"))]
+    pub tap_script_sigs: BTreeMap<(schnorr::PublicKey, TapLeafHash), schnorr::SchnorrSig>,
+    /// Map of Control blocks to Script version pair
+    #[cfg_attr(feature = "serde", serde(with = "::serde_utils::btreemap_as_seq"))]
+    pub tap_scripts: BTreeMap<ControlBlock, (Script, LeafVersion)>,
+    /// Map of tap root x only keys to origin info and leaf hashes contained in it
+    #[cfg_attr(feature = "serde", serde(with = "::serde_utils::btreemap_as_seq"))]
+    pub tap_key_origins: BTreeMap<schnorr::PublicKey, (Vec<TapLeafHash>, KeySource)>,
+    /// Taproot Internal key
+    pub tap_internal_key : Option<schnorr::PublicKey>,
+    /// Taproot Merkle root
+    pub tap_merkle_root : Option<TapBranchHash>,
     /// Proprietary key-value pairs for this input.
     #[cfg_attr(feature = "serde", serde(with = "::serde_utils::btreemap_as_seq_byte_values"))]
     pub proprietary: BTreeMap<raw::ProprietaryKey, Vec<u8>>,
@@ -177,6 +207,36 @@ impl Map for Input {
             PSBT_IN_HASH256 => {
                 psbt_insert_hash_pair(&mut self.hash256_preimages, raw_key, raw_value, error::PsbtHash::Hash256)?;
             }
+            PSBT_IN_TAP_KEY_SIG => {
+                impl_psbt_insert_pair! {
+                    self.tap_key_sig <= <raw_key: _>|<raw_value: schnorr::SchnorrSig>
+                }
+            }
+            PSBT_IN_TAP_SCRIPT_SIG => {
+                impl_psbt_insert_pair! {
+                    self.tap_script_sigs <= <raw_key: (schnorr::PublicKey, TapLeafHash)>|<raw_value: schnorr::SchnorrSig>
+                }
+            }
+            PSBT_IN_TAP_LEAF_SCRIPT=> {
+                impl_psbt_insert_pair! {
+                    self.tap_scripts <= <raw_key: ControlBlock>|< raw_value: (Script, LeafVersion)>
+                }
+            }
+            PSBT_IN_TAP_BIP32_DERIVATION => {
+                impl_psbt_insert_pair! {
+                    self.tap_key_origins <= <raw_key: schnorr::PublicKey>|< raw_value: (Vec<TapLeafHash>, KeySource)>
+                }
+            }
+            PSBT_IN_TAP_INTERNAL_KEY => {
+                impl_psbt_insert_pair! {
+                    self.tap_internal_key <= <raw_key: _>|< raw_value: schnorr::PublicKey>
+                }
+            }
+            PSBT_IN_TAP_MERKLE_ROOT => {
+                impl_psbt_insert_pair! {
+                    self.tap_merkle_root <= <raw_key: _>|< raw_value: TapBranchHash>
+                }
+            }
             PSBT_IN_PROPRIETARY => match self.proprietary.entry(raw::ProprietaryKey::from_key(raw_key.clone())?) {
                 btree_map::Entry::Vacant(empty_key) => {empty_key.insert(raw_value);},
                 btree_map::Entry::Occupied(_) => return Err(Error::DuplicateKey(raw_key).into()),
@@ -249,6 +309,30 @@ impl Map for Input {
             rv.push(self.hash256_preimages as <PSBT_IN_HASH256, sha256d::Hash>|<Vec<u8>>)
         }
 
+        impl_psbt_get_pair! {
+            rv.push(self.tap_key_sig as <PSBT_IN_TAP_KEY_SIG, _>|<Vec<u8>>)
+        }
+
+        impl_psbt_get_pair! {
+            rv.push(self.tap_script_sigs as <PSBT_IN_TAP_SCRIPT_SIG, (schnorr::PublicKey, TapLeafHash)>|<Vec<u8>>)
+        }
+
+        impl_psbt_get_pair! {
+            rv.push(self.tap_scripts as <PSBT_IN_TAP_LEAF_SCRIPT, ControlBlock>|<(Script, LeafVersion)>)
+        }
+
+        impl_psbt_get_pair! {
+            rv.push(self.tap_key_origins as <PSBT_IN_TAP_BIP32_DERIVATION,
+                schnorr::PublicKey>|<(Vec<TapLeafHash>, KeySource)>)
+        }
+
+        impl_psbt_get_pair! {
+            rv.push(self.tap_internal_key as <PSBT_IN_TAP_INTERNAL_KEY, _>|<schnorr::PublicKey>)
+        }
+
+        impl_psbt_get_pair! {
+            rv.push(self.tap_merkle_root as <PSBT_IN_TAP_MERKLE_ROOT, _>|<TapBranchHash>)
+        }
         for (key, value) in self.proprietary.iter() {
             rv.push(raw::Pair {
                 key: key.to_key(),
@@ -280,13 +364,19 @@ impl Map for Input {
         self.sha256_preimages.extend(other.sha256_preimages);
         self.hash160_preimages.extend(other.hash160_preimages);
         self.hash256_preimages.extend(other.hash256_preimages);
+        self.tap_script_sigs.extend(other.tap_script_sigs);
+        self.tap_scripts.extend(other.tap_scripts);
+        self.tap_key_origins.extend(other.tap_key_origins);
         self.proprietary.extend(other.proprietary);
         self.unknown.extend(other.unknown);
 
         merge!(redeem_script, self, other);
         merge!(witness_script, self, other);
         merge!(final_script_sig, self, other);
         merge!(final_script_witness, self, other);
+        merge!(tap_key_sig, self, other);
+        merge!(tap_internal_key, self, other);
+        merge!(tap_merkle_root, self, other);
 
         Ok(())
     }

src/util/psbt/map/mod.rs

@@ -55,3 +55,4 @@ mod output;
 
 pub use self::input::Input;
 pub use self::output::Output;
+pub use self::output::TapTree;

src/util/psbt/map/output.rs

@@ -25,12 +25,23 @@ use util::psbt::map::Map;
 use util::psbt::raw;
 use util::psbt::Error;
 
+use schnorr;
+use util::taproot::TapLeafHash;
+
+use util::taproot::{NodeInfo, TaprootBuilder};
+
 /// Type: Redeem Script PSBT_OUT_REDEEM_SCRIPT = 0x00
 const PSBT_OUT_REDEEM_SCRIPT: u8 = 0x00;
 /// Type: Witness Script PSBT_OUT_WITNESS_SCRIPT = 0x01
 const PSBT_OUT_WITNESS_SCRIPT: u8 = 0x01;
 /// Type: BIP 32 Derivation Path PSBT_OUT_BIP32_DERIVATION = 0x02
 const PSBT_OUT_BIP32_DERIVATION: u8 = 0x02;
+/// Type: Taproot Internal Key PSBT_OUT_TAP_INTERNAL_KEY = 0x05
+const PSBT_OUT_TAP_INTERNAL_KEY: u8 = 0x05;
+/// Type: Taproot Tree PSBT_OUT_TAP_TREE = 0x06
+const PSBT_OUT_TAP_TREE: u8 = 0x06;
+/// Type: Taproot Key BIP 32 Derivation Path PSBT_OUT_TAP_BIP32_DERIVATION = 0x07
+const PSBT_OUT_TAP_BIP32_DERIVATION: u8 = 0x07;
 /// Type: Proprietary Use Type PSBT_IN_PROPRIETARY = 0xFC
 const PSBT_OUT_PROPRIETARY: u8 = 0xFC;
 
@@ -47,14 +58,67 @@ pub struct Output {
     /// corresponding master key fingerprints and derivation paths.
     #[cfg_attr(feature = "serde", serde(with = "::serde_utils::btreemap_as_seq"))]
     pub bip32_derivation: BTreeMap<PublicKey, KeySource>,
+    /// The internal pubkey
+    pub tap_internal_key: Option<schnorr::PublicKey>,
+    /// Taproot Output tree
+    pub tap_tree: Option<TapTree>,
+    /// Map of tap root x only keys to origin info and leaf hashes contained in it
+    #[cfg_attr(feature = "serde", serde(with = "::serde_utils::btreemap_as_seq"))]
+    pub tap_key_origins: BTreeMap<schnorr::PublicKey, (Vec<TapLeafHash>, KeySource)>,
     /// Proprietary key-value pairs for this output.
-    #[cfg_attr(feature = "serde", serde(with = "::serde_utils::btreemap_as_seq_byte_values"))]
+    #[cfg_attr(
+        feature = "serde",
+        serde(with = "::serde_utils::btreemap_as_seq_byte_values")
+    )]
     pub proprietary: BTreeMap<raw::ProprietaryKey, Vec<u8>>,
     /// Unknown key-value pairs for this output.
-    #[cfg_attr(feature = "serde", serde(with = "::serde_utils::btreemap_as_seq_byte_values"))]
+    #[cfg_attr(
+        feature = "serde",
+        serde(with = "::serde_utils::btreemap_as_seq_byte_values")
+    )]
     pub unknown: BTreeMap<raw::Key, Vec<u8>>,
 }
 
+/// Taproot Tree representing a finalized [`TaprootBuilder`] (a complete binary tree)
+#[derive(Clone, Debug)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub struct TapTree(pub(crate) TaprootBuilder);
+
+impl PartialEq for TapTree {
+    fn eq(&self, other: &Self) -> bool {
+        self.node_info().hash.eq(&other.node_info().hash)
+    }
+}
+
+impl Eq for TapTree {}
+
+impl TapTree {
+    // get the inner node info as the builder is finalized
+    fn node_info(&self) -> &NodeInfo {
+        // The builder algorithm invariant guarantees that is_complete builder
+        // have only 1 element in branch and that is not None.
+        // We make sure that we only allow is_complete builders via the from_inner
+        // constructor
+        self.0.branch()[0].as_ref().expect("from_inner only parses is_complete builders")
+    }
+
+    /// Convert a [`TaprootBuilder`] into a tree if it is complete binary tree.
+    /// Returns the inner as Err if it is not a complete tree
+    pub fn from_inner(inner: TaprootBuilder) -> Result<Self, TaprootBuilder> {
+        if inner.is_complete() {
+            Ok(TapTree(inner))
+        } else {
+            Err(inner)
+        }
+    }
+
+    /// Convert self into builder [`TaprootBuilder`]. The builder is guaranteed to
+    /// be finalized.
+    pub fn into_inner(self) -> TaprootBuilder {
+        self.0
+    }
+}
+
 impl Map for Output {
     fn insert_pair(&mut self, pair: raw::Pair) -> Result<(), encode::Error> {
         let raw::Pair {
@@ -82,10 +146,29 @@ impl Map for Output {
                 btree_map::Entry::Vacant(empty_key) => {empty_key.insert(raw_value);},
                 btree_map::Entry::Occupied(_) => return Err(Error::DuplicateKey(raw_key).into()),
             }
-            _ => match self.unknown.entry(raw_key) {
-                btree_map::Entry::Vacant(empty_key) => {empty_key.insert(raw_value);},
-                btree_map::Entry::Occupied(k) => return Err(Error::DuplicateKey(k.key().clone()).into()),
+            PSBT_OUT_TAP_INTERNAL_KEY => {
+                impl_psbt_insert_pair! {
+                    self.tap_internal_key <= <raw_key: _>|<raw_value: schnorr::PublicKey>
+                }
+            }
+            PSBT_OUT_TAP_TREE => {
+                impl_psbt_insert_pair! {
+                    self.tap_tree <= <raw_key: _>|<raw_value: TapTree>
+                }
+            }
+            PSBT_OUT_TAP_BIP32_DERIVATION => {
+                impl_psbt_insert_pair! {
+                    self.tap_key_origins <= <raw_key: schnorr::PublicKey>|< raw_value: (Vec<TapLeafHash>, KeySource)>
+                }
             }
+            _ => match self.unknown.entry(raw_key) {
+                btree_map::Entry::Vacant(empty_key) => {
+                    empty_key.insert(raw_value);
+                }
+                btree_map::Entry::Occupied(k) => {
+                    return Err(Error::DuplicateKey(k.key().clone()).into())
+                }
+            },
         }
 
         Ok(())
@@ -106,6 +189,19 @@ impl Map for Output {
             rv.push(self.bip32_derivation as <PSBT_OUT_BIP32_DERIVATION, PublicKey>|<KeySource>)
         }
 
+        impl_psbt_get_pair! {
+            rv.push(self.tap_internal_key as <PSBT_OUT_TAP_INTERNAL_KEY, _>|<schnorr::PublicKey>)
+        }
+
+        impl_psbt_get_pair! {
+            rv.push(self.tap_tree as <PSBT_OUT_TAP_TREE, _>|<TaprootBuilder>)
+        }
+
+        impl_psbt_get_pair! {
+            rv.push(self.tap_key_origins as <PSBT_OUT_TAP_BIP32_DERIVATION,
+                    schnorr::PublicKey>|<(Vec<TapLeafHash>, KeySource)>)
+        }
+
         for (key, value) in self.proprietary.iter() {
             rv.push(raw::Pair {
                 key: key.to_key(),
@@ -127,9 +223,12 @@ impl Map for Output {
         self.bip32_derivation.extend(other.bip32_derivation);
         self.proprietary.extend(other.proprietary);
         self.unknown.extend(other.unknown);
+        self.tap_key_origins.extend(other.tap_key_origins);
 
         merge!(redeem_script, self, other);
         merge!(witness_script, self, other);
+        merge!(tap_internal_key, self, other);
+        merge!(tap_tree, self, other);
 
         Ok(())
     }