Implement P2WPKH & P2WSH output spend script

diff --git a/bitcoin/src/blockdata/script/mod.rs b/bitcoin/src/blockdata/script/mod.rs
index 9fa8e3bb..cea6378c 100644
--- a/bitcoin/src/blockdata/script/mod.rs
+++ b/bitcoin/src/blockdata/script/mod.rs
@@ -71,7 +71,7 @@ pub use self::{
     borrowed::{ScriptExt, TapScriptExt, ScriptPubKeyExt, WitnessScriptExt, ScriptSigExt},
     builder::Builder,
     instruction::{Instruction, Instructions, InstructionIndices},
-    owned::{ScriptBufExt, ScriptPubKeyBufExt},
+    owned::{ScriptBufExt, ScriptPubKeyBufExt, ScriptSigBufExt},
     push_bytes::{PushBytes, PushBytesBuf, PushBytesErrorReport},
 };
 #[doc(no_inline)]
diff --git a/bitcoin/src/blockdata/script/owned.rs b/bitcoin/src/blockdata/script/owned.rs
index f83d4053..c3d59126 100644
--- a/bitcoin/src/blockdata/script/owned.rs
+++ b/bitcoin/src/blockdata/script/owned.rs
@@ -7,11 +7,12 @@ use internals::ToU64 as _;
 
 use super::{
     opcode_to_verify, write_scriptint, Builder, Error, Instruction, PushBytes, ScriptBuf,
-    ScriptExtPriv as _, ScriptPubKeyBuf,
+    ScriptExtPriv as _, ScriptPubKeyBuf, ScriptSigBuf, WitnessScript,
 };
 use crate::internal_macros;
 use crate::key::{
-    LegacyPublicKey, PubkeyHash, TapTweak, TweakedPublicKey, UntweakedPublicKey, WPubkeyHash,
+    FullPublicKey, LegacyPublicKey, PubkeyHash, TapTweak, TweakedPublicKey, UntweakedPublicKey,
+    WPubkeyHash,
 };
 use crate::opcodes::all::*;
 use crate::opcodes::{self, Opcode};
@@ -234,6 +235,38 @@ crate::internal_macros::define_extension_trait! {
     }
 }
 
+crate::internal_macros::define_extension_trait! {
+    /// Extension functionality for the [`ScriptSigBuf`] type.
+    pub trait ScriptSigBufExt impl for ScriptSigBuf {
+        /// Constructs a scriptSig required to spend a P2SH-P2WPKH output.
+        ///
+        /// The scriptSig pushes the P2WPKH redeem script (`0 <20-byte-pubkey-hash>`) which
+        /// is required when spending a P2SH-wrapped Segwit output. The witness data should
+        /// be provided separately using [`WitnessExt::p2wpkh`].
+        ///
+        /// [`WitnessExt::p2wpkh`]: crate::blockdata::witness::WitnessExt::p2wpkh
+        fn p2sh_p2wpkh(pubkey: FullPublicKey) -> Self {
+            let redeem_script: super::ScriptPubKeyBuf = Builder::new().push_int_unchecked(0).push_slice(pubkey.wpubkey_hash()).into_script();
+            Builder::new().push_slice(<&PushBytes>::try_from(redeem_script.as_bytes()).expect("redeem script is 22 bytes")).into_script()
+        }
+
+        /// Constructs a scriptSig required to spend a P2SH-P2WSH output.
+        ///
+        /// The scriptSig pushes the P2WSH redeem script (`0 <32-byte-script-hash>`) which
+        /// is required when spending a P2SH-wrapped Segwit output. The witness data should
+        /// be provided separately using [`WitnessExt::p2wsh`].
+        ///
+        /// [`WitnessExt::p2wsh`]: crate::blockdata::witness::WitnessExt::p2wsh
+        fn p2sh_p2wsh(witness_script: &WitnessScript) -> Result<ScriptSigBuf, super::WitnessScriptSizeError> {
+            use super::WitnessScriptExt as _;
+
+            let hash = witness_script.wscript_hash()?;
+            let redeem_script: super::ScriptPubKeyBuf = Builder::new().push_int_unchecked(0).push_slice(hash).into_script();
+            Ok(Builder::new().push_slice(<&PushBytes>::try_from(redeem_script.as_bytes()).expect("redeem script is 34 bytes")).into_script())
+        }
+    }
+}
+
 mod sealed {
     pub trait Sealed {}
     impl<T> Sealed for super::ScriptBuf<T> {}
diff --git a/bitcoin/src/blockdata/script/tests.rs b/bitcoin/src/blockdata/script/tests.rs
index ff25a9b5..4af492e9 100644
--- a/bitcoin/src/blockdata/script/tests.rs
+++ b/bitcoin/src/blockdata/script/tests.rs
@@ -8,8 +8,9 @@ use hex_unstable::hex;
 
 use super::*;
 use crate::consensus::encode::{deserialize, serialize};
-use crate::crypto::key::{LegacyPublicKey, XOnlyPublicKey};
+use crate::crypto::key::{FullPublicKey, LegacyPublicKey, XOnlyPublicKey};
 use crate::script::borrowed::{ScriptPubKeyExt as _, ScriptPubKeyExtPriv as _, TapScriptExt as _};
+use crate::script::owned::ScriptSigBufExt as _;
 use crate::script::witness_program::WitnessProgram;
 use crate::script::witness_version::WitnessVersion;
 use crate::{opcodes, Amount, FeeRate};
@@ -1079,3 +1080,29 @@ fn longest_witness_program() {
 
     assert_eq!(script.witness_version(), Some(version));
 }
+
+#[test]
+fn p2sh_p2wpkh_script_sig() {
+    let key = "026c468be64d22761c30cd2f12cbc7de255d592d7904b1bab07236897cc4c2e766"
+        .parse::<FullPublicKey>()
+        .unwrap();
+    let script_sig = crate::ScriptSigBuf::p2sh_p2wpkh(key);
+
+    // The scriptSig should be a single push of the 22-byte redeem script: 0014<20-byte-hash>
+    let redeem_script = script_sig.redeem_script().expect("should have redeem script");
+    assert_eq!(redeem_script.as_bytes()[0], 0x00); // witness version 0
+    assert_eq!(redeem_script.as_bytes()[1], 0x14); // push 20 bytes
+    assert_eq!(redeem_script.len(), 22);
+}
+
+#[test]
+fn p2sh_p2wsh_script_sig() {
+    let witness_script = WitnessScriptBuf::from_hex_no_length_prefix("522103e5529d8eaa3d559903adb2e881eb06c86ac2574ffa503c45f4e942e2a693b33e2102e5f10fcdcdbab211e0af6a481f5532536ec61a5fdbf7183770cf8680fe729d8152ae").unwrap();
+    let script_sig = crate::ScriptSigBuf::p2sh_p2wsh(&witness_script).expect("script is valid");
+
+    // The scriptSig should be a single push of the 34-byte redeem script: 0020<32-byte-hash>
+    let redeem_script = script_sig.redeem_script().expect("should have redeem script");
+    assert_eq!(redeem_script.as_bytes()[0], 0x00); // witness version 0
+    assert_eq!(redeem_script.as_bytes()[1], 0x20); // push 32 bytes
+    assert_eq!(redeem_script.len(), 34);
+}