Add method to convert expr_raw_pkh into pkh

The commit adds up the method to convert the expr_raw_pkh into pkh by
looking at the available keys and their hases being stored inside of the Hashmap of PSBT Input.
If the key is found corresponding to given hash, It will update to pkh.

Signed-off-by: Harshil Jani <[email protected]>

Author: Harshil-Jani

src/miniscript/astelem.rs

@@ -179,6 +179,75 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> Terminal<Pk, Ctx> {
         };
         Ok(frag)
     }
+
+    /// Substitutes raw public keys hashes with the public keys as provided by map.
+    pub fn substitute_raw_pkh(&self, pk_map: &HashMap<hash160::Hash, Pk>) -> Terminal<Pk, Ctx> {
+        match self {
+            Terminal::RawPkH(ref p) => match pk_map.get(p) {
+                Some(pk) => Terminal::PkH(pk.clone()).into(),
+                None => Terminal::RawPkH(*p).into(),
+            },
+            Terminal::PkK(..)
+            | Terminal::PkH(..)
+            | Terminal::Multi(..)
+            | Terminal::MultiA(..)
+            | Terminal::After(..)
+            | Terminal::Older(..)
+            | Terminal::Sha256(..)
+            | Terminal::Hash256(..)
+            | Terminal::Ripemd160(..)
+            | Terminal::Hash160(..)
+            | Terminal::True
+            | Terminal::False => self.clone().into(),
+            Terminal::Alt(ref sub) => Terminal::Alt(Arc::new(sub.substitute_raw_pkh(pk_map))),
+            Terminal::Swap(ref sub) => Terminal::Swap(Arc::new(sub.substitute_raw_pkh(pk_map))),
+            Terminal::Check(ref sub) => Terminal::Check(Arc::new(sub.substitute_raw_pkh(pk_map))),
+            Terminal::DupIf(ref sub) => Terminal::DupIf(Arc::new(sub.substitute_raw_pkh(pk_map))),
+            Terminal::Verify(ref sub) => Terminal::Verify(Arc::new(sub.substitute_raw_pkh(pk_map))),
+            Terminal::NonZero(ref sub) => {
+                Terminal::NonZero(Arc::new(sub.substitute_raw_pkh(pk_map)))
+            }
+            Terminal::ZeroNotEqual(ref sub) => {
+                Terminal::ZeroNotEqual(Arc::new(sub.substitute_raw_pkh(pk_map)))
+            }
+            Terminal::AndV(ref left, ref right) => Terminal::AndV(
+                Arc::new(left.substitute_raw_pkh(pk_map)),
+                Arc::new(right.substitute_raw_pkh(pk_map)),
+            ),
+            Terminal::AndB(ref left, ref right) => Terminal::AndB(
+                Arc::new(left.substitute_raw_pkh(pk_map)),
+                Arc::new(right.substitute_raw_pkh(pk_map)),
+            ),
+            Terminal::AndOr(ref a, ref b, ref c) => Terminal::AndOr(
+                Arc::new(a.substitute_raw_pkh(pk_map)),
+                Arc::new(b.substitute_raw_pkh(pk_map)),
+                Arc::new(c.substitute_raw_pkh(pk_map)),
+            ),
+            Terminal::OrB(ref left, ref right) => Terminal::OrB(
+                Arc::new(left.substitute_raw_pkh(pk_map)),
+                Arc::new(right.substitute_raw_pkh(pk_map)),
+            ),
+            Terminal::OrD(ref left, ref right) => Terminal::OrD(
+                Arc::new(left.substitute_raw_pkh(pk_map)),
+                Arc::new(right.substitute_raw_pkh(pk_map)),
+            ),
+            Terminal::OrC(ref left, ref right) => Terminal::OrC(
+                Arc::new(left.substitute_raw_pkh(pk_map)),
+                Arc::new(right.substitute_raw_pkh(pk_map)),
+            ),
+            Terminal::OrI(ref left, ref right) => Terminal::OrI(
+                Arc::new(left.substitute_raw_pkh(pk_map)),
+                Arc::new(right.substitute_raw_pkh(pk_map)),
+            ),
+            Terminal::Thresh(k, ref subs) => {
+                let subs: Vec<Arc<Miniscript<_, _>>> = subs
+                    .iter()
+                    .map(|s| Arc::new(s.substitute_raw_pkh(pk_map)))
+                    .collect();
+                Terminal::Thresh(*k, subs)
+            }
+        }
+    }
 }
 
 impl<Pk: MiniscriptKey, Ctx: ScriptContext> ForEachKey<Pk> for Terminal<Pk, Ctx> {

src/miniscript/mod.rs

@@ -16,6 +16,7 @@
 use core::marker::PhantomData;
 use core::{fmt, hash, str};
 
+use bitcoin::hashes::hash160;
 use bitcoin::script;
 use bitcoin::taproot::{LeafVersion, TapLeafHash};
 
@@ -334,6 +335,11 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> Miniscript<Pk, Ctx> {
         let inner = self.node.real_translate_pk(t)?;
         Miniscript::from_ast(inner).map_err(TranslateErr::OuterError)
     }
+
+    /// Substitutes raw public keys hashes with the public keys as provided by map.
+    pub fn substitute_raw_pkh(&self, pk_map: &HashMap<hash160::Hash, Pk>) -> Miniscript<Pk, Ctx> {
+        Miniscript::from_ast(self.node.substitute_raw_pkh(pk_map)).expect("type check failed")
+    }
 }
 
 impl_block_str!(

src/psbt/finalizer.rs

@@ -8,11 +8,13 @@
 //! `https://github.com/bitcoin/bips/blob/master/bip-0174.mediawiki`
 //!
 
+use bitcoin::hashes::hash160;
 use bitcoin::key::XOnlyPublicKey;
 use bitcoin::secp256k1::{self, Secp256k1};
 use bitcoin::sighash::Prevouts;
 use bitcoin::taproot::LeafVersion;
 use bitcoin::{PublicKey, Script, ScriptBuf, TxOut, Witness};
+use std::collections::HashMap;
 
 use super::{sanity_check, Error, InputError, Psbt, PsbtInputSatisfier};
 use crate::prelude::*;
@@ -122,6 +124,22 @@ pub(super) fn prevouts(psbt: &Psbt) -> Result<Vec<&bitcoin::TxOut>, super::Error
 // we want to move the script is probably already created
 // and we want to satisfy it in any way possible.
 fn get_descriptor(psbt: &Psbt, index: usize) -> Result<Descriptor<PublicKey>, InputError> {
+    // Create a HashMap <Hash(Pk),Pk>
+    let mut hash_map: HashMap<hash160::Hash, PublicKey> = HashMap::new();
+    let psbt_inputs = &psbt.inputs;
+    for psbt_input in psbt_inputs {
+        // Use BIP32 Derviation to get set of all possible keys.
+        let public_keys = psbt_input.bip32_derivation.keys();
+        for key in public_keys {
+            // Convert bitcoin::secp256k1::PublicKey into just bitcoin::PublicKey
+            let bitcoin_key = bitcoin::PublicKey::new(*key);
+            // Convert PubKeyHash into Hash::hash160
+            let hash = bitcoin_key.pubkey_hash().to_raw_hash();
+            // Insert pair in HashMap
+            hash_map.insert(hash, bitcoin_key);
+        }
+    }
+
     // Figure out Scriptpubkey
     let script_pubkey = get_scriptpubkey(psbt, index)?;
     let inp = &psbt.inputs[index];
@@ -178,7 +196,7 @@ fn get_descriptor(psbt: &Psbt, index: usize) -> Result<Descriptor<PublicKey>, In
                 witness_script,
                 &ExtParams::allow_all(),
             )?;
-            Ok(Descriptor::new_wsh(ms)?)
+            Ok(Descriptor::new_wsh(ms.substitute_raw_pkh(&hash_map))?)
         } else {
             Err(InputError::MissingWitnessScript)
         }
@@ -205,7 +223,7 @@ fn get_descriptor(psbt: &Psbt, index: usize) -> Result<Descriptor<PublicKey>, In
                             witness_script,
                             &ExtParams::allow_all(),
                         )?;
-                        Ok(Descriptor::new_sh_wsh(ms)?)
+                        Ok(Descriptor::new_sh_wsh(ms.substitute_raw_pkh(&hash_map))?)
                     } else {
                         Err(InputError::MissingWitnessScript)
                     }
@@ -249,7 +267,7 @@ fn get_descriptor(psbt: &Psbt, index: usize) -> Result<Descriptor<PublicKey>, In
             &script_pubkey,
             &ExtParams::allow_all(),
         )?;
-        Ok(Descriptor::new_bare(ms)?)
+        Ok(Descriptor::new_bare(ms.substitute_raw_pkh(&hash_map))?)
     }
 }