primitives: split ScriptSig and ScriptSigBuf from Script and ScriptBuf

diff --git a/bitcoin/examples/ecdsa-psbt-simple.rs b/bitcoin/examples/ecdsa-psbt-simple.rs
index 94076b46..a2160c03 100644
--- a/bitcoin/examples/ecdsa-psbt-simple.rs
+++ b/bitcoin/examples/ecdsa-psbt-simple.rs
@@ -32,7 +32,7 @@ use bitcoin::psbt::Input;
 use bitcoin::secp256k1::{Secp256k1, Signing};
 use bitcoin::{
     consensus, transaction, Address, Amount, EcdsaSighashType, Network, OutPoint, Psbt, ScriptBuf,
-    Sequence, Transaction, TxIn, TxOut, Txid, Witness,
+    ScriptSigBuf, Sequence, Transaction, TxIn, TxOut, Txid, Witness,
 };
 
 // The master xpriv, from which we derive the keys we control.
@@ -157,7 +157,7 @@ fn main() {
         .into_iter()
         .map(|(outpoint, _)| TxIn {
             previous_output: outpoint,
-            script_sig: ScriptBuf::default(),
+            script_sig: ScriptSigBuf::default(),
             sequence: Sequence::ENABLE_LOCKTIME_AND_RBF,
             witness: Witness::default(),
         })
diff --git a/bitcoin/examples/ecdsa-psbt.rs b/bitcoin/examples/ecdsa-psbt.rs
index 4d3e2a01..50948d1d 100644
--- a/bitcoin/examples/ecdsa-psbt.rs
+++ b/bitcoin/examples/ecdsa-psbt.rs
@@ -38,8 +38,8 @@ use bitcoin::locktime::absolute;
 use bitcoin::psbt::{self, Input, Psbt, PsbtSighashType};
 use bitcoin::secp256k1::{Secp256k1, Signing, Verification};
 use bitcoin::{
-    transaction, Address, Amount, CompressedPublicKey, Network, OutPoint, ScriptBuf, Sequence,
-    Transaction, TxIn, TxOut, Witness,
+    transaction, Address, Amount, CompressedPublicKey, Network, OutPoint, ScriptBuf, ScriptSigBuf,
+    Sequence, Transaction, TxIn, TxOut, Witness,
 };
 
 type Result<T> = std::result::Result<T, Error>;
@@ -186,7 +186,7 @@ impl WatchOnly {
             lock_time: absolute::LockTime::ZERO,
             inputs: vec![TxIn {
                 previous_output: OutPoint { txid: INPUT_UTXO_TXID.parse()?, vout: INPUT_UTXO_VOUT },
-                script_sig: ScriptBuf::new(),
+                script_sig: ScriptSigBuf::new(),
                 sequence: Sequence::MAX, // Disable LockTime and RBF.
                 witness: Witness::default(),
             }],
diff --git a/bitcoin/examples/sign-tx-segwit-v0.rs b/bitcoin/examples/sign-tx-segwit-v0.rs
index de41c91c..5e514b12 100644
--- a/bitcoin/examples/sign-tx-segwit-v0.rs
+++ b/bitcoin/examples/sign-tx-segwit-v0.rs
@@ -8,8 +8,8 @@ use bitcoin::locktime::absolute;
 use bitcoin::secp256k1::{rand, Message, Secp256k1, SecretKey, Signing};
 use bitcoin::sighash::{EcdsaSighashType, SighashCache};
 use bitcoin::{
-    transaction, Address, Amount, Network, OutPoint, ScriptBuf, Sequence, Transaction, TxIn, TxOut,
-    Txid, Witness,
+    transaction, Address, Amount, Network, OutPoint, ScriptBuf, ScriptSigBuf, Sequence,
+    Transaction, TxIn, TxOut, Txid, Witness,
 };
 
 const DUMMY_UTXO_AMOUNT: Amount = Amount::from_sat_u32(20_000_000);
@@ -33,7 +33,7 @@ fn main() {
     // The input for the transaction we are constructing.
     let input = TxIn {
         previous_output: dummy_out_point, // The dummy output we are spending.
-        script_sig: ScriptBuf::default(), // For a p2wpkh script_sig is empty.
+        script_sig: ScriptSigBuf::default(), // For a p2wpkh script_sig is empty.
         sequence: Sequence::ENABLE_LOCKTIME_AND_RBF,
         witness: Witness::default(), // Filled in after signing.
     };
diff --git a/bitcoin/examples/sign-tx-taproot.rs b/bitcoin/examples/sign-tx-taproot.rs
index eaac84c7..883aa353 100644
--- a/bitcoin/examples/sign-tx-taproot.rs
+++ b/bitcoin/examples/sign-tx-taproot.rs
@@ -8,8 +8,8 @@ use bitcoin::locktime::absolute;
 use bitcoin::secp256k1::{rand, Secp256k1, SecretKey, Signing, Verification};
 use bitcoin::sighash::{Prevouts, SighashCache, TapSighashType};
 use bitcoin::{
-    transaction, Address, Amount, Network, OutPoint, ScriptBuf, Sequence, Transaction, TxIn, TxOut,
-    Txid, Witness,
+    transaction, Address, Amount, Network, OutPoint, ScriptBuf, ScriptSigBuf, Sequence,
+    Transaction, TxIn, TxOut, Txid, Witness,
 };
 
 const DUMMY_UTXO_AMOUNT: Amount = Amount::from_sat_u32(20_000_000);
@@ -33,7 +33,7 @@ fn main() {
     // The input for the transaction we are constructing.
     let input = TxIn {
         previous_output: dummy_out_point, // The dummy output we are spending.
-        script_sig: ScriptBuf::default(), // For a p2tr script_sig is empty.
+        script_sig: ScriptSigBuf::default(), // For a p2tr script_sig is empty.
         sequence: Sequence::ENABLE_LOCKTIME_AND_RBF,
         witness: Witness::default(), // Filled in after signing.
     };
diff --git a/bitcoin/examples/taproot-psbt-simple.rs b/bitcoin/examples/taproot-psbt-simple.rs
index 8ba75a05..e252af60 100644
--- a/bitcoin/examples/taproot-psbt-simple.rs
+++ b/bitcoin/examples/taproot-psbt-simple.rs
@@ -29,8 +29,8 @@ use bitcoin::locktime::absolute;
 use bitcoin::psbt::Input;
 use bitcoin::secp256k1::{Secp256k1, Signing};
 use bitcoin::{
-    consensus, transaction, Address, Amount, Network, OutPoint, Psbt, ScriptBuf, Sequence,
-    TapLeafHash, TapSighashType, Transaction, TxIn, TxOut, Txid, Witness, XOnlyPublicKey,
+    consensus, transaction, Address, Amount, Network, OutPoint, Psbt, ScriptBuf, ScriptSigBuf,
+    Sequence, TapLeafHash, TapSighashType, Transaction, TxIn, TxOut, Txid, Witness, XOnlyPublicKey,
 };
 
 // The master xpriv, from which we derive the keys we control.
@@ -177,7 +177,7 @@ fn main() {
         .into_iter()
         .map(|(outpoint, _)| TxIn {
             previous_output: outpoint,
-            script_sig: ScriptBuf::default(),
+            script_sig: ScriptSigBuf::default(),
             sequence: Sequence::ENABLE_LOCKTIME_AND_RBF,
             witness: Witness::default(),
         })
diff --git a/bitcoin/examples/taproot-psbt.rs b/bitcoin/examples/taproot-psbt.rs
index 918eab67..a5e34d97 100644
--- a/bitcoin/examples/taproot-psbt.rs
+++ b/bitcoin/examples/taproot-psbt.rs
@@ -87,8 +87,8 @@ use bitcoin::secp256k1::Secp256k1;
 use bitcoin::sighash::{self, SighashCache, TapSighash, TapSighashType};
 use bitcoin::taproot::{self, LeafVersion, TapLeafHash, TaprootBuilder, TaprootSpendInfo};
 use bitcoin::{
-    absolute, script, transaction, Address, Amount, Network, OutPoint, ScriptBuf, Transaction,
-    TxIn, TxOut, Witness,
+    absolute, script, transaction, Address, Amount, Network, OutPoint, ScriptBuf, ScriptSigBuf,
+    Transaction, TxIn, TxOut, Witness,
 };
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
@@ -232,7 +232,7 @@ fn generate_bip86_key_spend_tx(
         lock_time: absolute::LockTime::ZERO,
         inputs: vec![TxIn {
             previous_output: OutPoint { txid: input_utxo.txid.parse()?, vout: input_utxo.vout },
-            script_sig: ScriptBuf::new(),
+            script_sig: ScriptSigBuf::new(),
             sequence: bitcoin::Sequence(0xFFFFFFFF), // Ignore nSequence.
             witness: Witness::default(),
         }],
@@ -429,7 +429,7 @@ impl BenefactorWallet {
             lock_time,
             inputs: vec![TxIn {
                 previous_output: OutPoint { txid: tx.compute_txid(), vout: 0 },
-                script_sig: ScriptBuf::new(),
+                script_sig: ScriptSigBuf::new(),
                 sequence: bitcoin::Sequence(0xFFFFFFFD), // enable locktime and opt-in RBF
                 witness: Witness::default(),
             }],
@@ -579,7 +579,7 @@ impl BenefactorWallet {
                 lock_time,
                 inputs: vec![TxIn {
                     previous_output: OutPoint { txid: tx.compute_txid(), vout: 0 },
-                    script_sig: ScriptBuf::new(),
+                    script_sig: ScriptSigBuf::new(),
                     sequence: bitcoin::Sequence(0xFFFFFFFD), // enable locktime and opt-in RBF
                     witness: Witness::default(),
                 }],
diff --git a/bitcoin/src/bip152.rs b/bitcoin/src/bip152.rs
index 8d1a09fb..fd969eef 100644
--- a/bitcoin/src/bip152.rs
+++ b/bitcoin/src/bip152.rs
@@ -460,8 +460,8 @@ mod test {
     use crate::merkle_tree::TxMerkleNode;
     use crate::transaction::OutPointExt;
     use crate::{
-        transaction, Amount, BlockChecked, BlockTime, CompactTarget, OutPoint, ScriptBuf, Sequence,
-        TxIn, TxOut, Txid, Witness,
+        transaction, Amount, BlockChecked, BlockTime, CompactTarget, OutPoint, ScriptBuf,
+        ScriptSigBuf, Sequence, TxIn, TxOut, Txid, Witness,
     };
 
     fn dummy_tx(nonce: &[u8]) -> Transaction {
@@ -471,7 +471,7 @@ mod test {
             lock_time: absolute::LockTime::from_consensus(2),
             inputs: vec![TxIn {
                 previous_output: OutPoint::new(dummy_txid, 0),
-                script_sig: ScriptBuf::new(),
+                script_sig: ScriptSigBuf::new(),
                 sequence: Sequence(1),
                 witness: Witness::new(),
             }],
diff --git a/bitcoin/src/blockdata/block.rs b/bitcoin/src/blockdata/block.rs
index ff59bfc1..60087d35 100644
--- a/bitcoin/src/blockdata/block.rs
+++ b/bitcoin/src/blockdata/block.rs
@@ -535,7 +535,7 @@ mod tests {
     use super::*;
     use crate::consensus::encode::{deserialize, serialize};
     use crate::pow::test_utils::{u128_to_work, u64_to_work};
-    use crate::script::ScriptBuf;
+    use crate::script::{ScriptBuf, ScriptSigBuf};
     use crate::transaction::{OutPoint, Transaction, TxIn, TxOut, Txid};
     use crate::{block, Amount, CompactTarget, Network, Sequence, TestnetVersion, Witness};
 
@@ -811,7 +811,7 @@ mod tests {
                     txid: Txid::from_byte_array([1; 32]), // Not all zeros
                     vout: 0,
                 },
-                script_sig: ScriptBuf::new(),
+                script_sig: ScriptSigBuf::new(),
                 sequence: Sequence::ENABLE_LOCKTIME_AND_RBF,
                 witness: Witness::new(),
             }],
@@ -887,7 +887,7 @@ mod tests {
                     txid: Txid::from_byte_array([1; 32]), // Not all zeros
                     vout: 0,
                 },
-                script_sig: ScriptBuf::new(),
+                script_sig: ScriptSigBuf::new(),
                 sequence: Sequence::ENABLE_LOCKTIME_AND_RBF,
                 witness: Witness::new(),
             }],
diff --git a/bitcoin/src/blockdata/script/borrowed.rs b/bitcoin/src/blockdata/script/borrowed.rs
index 8151e10c..f460d698 100644
--- a/bitcoin/src/blockdata/script/borrowed.rs
+++ b/bitcoin/src/blockdata/script/borrowed.rs
@@ -10,7 +10,7 @@ use secp256k1::{Secp256k1, Verification};
 use super::witness_version::WitnessVersion;
 use super::{
     Builder, GenericScript, Instruction, InstructionIndices, Instructions, PushBytes,
-    RedeemScriptSizeError, Script, ScriptHash, WScriptHash, WitnessScriptSizeError,
+    RedeemScriptSizeError, Script, ScriptHash, ScriptSig, WScriptHash, WitnessScriptSizeError,
 };
 use crate::consensus::{self, Encodable};
 use crate::key::{PublicKey, UntweakedPublicKey, WPubkeyHash};
@@ -28,6 +28,55 @@ internal_macros::define_extension_trait! {
         /// Constructs a new script builder
         fn builder() -> Builder<T> { Builder::new() }
 
+        /// Counts the sigops for this Script using accurate counting.
+        ///
+        /// In Bitcoin Core, there are two ways to count sigops, "accurate" and "legacy".
+        /// This method uses "accurate" counting. This means that OP_CHECKMULTISIG and its
+        /// verify variant count for N sigops where N is the number of pubkeys used in the
+        /// multisig. However, it will count for 20 sigops if CHECKMULTISIG is not preceded by an
+        /// OP_PUSHNUM from 1 - 16 (this would be an invalid script)
+        ///
+        /// Bitcoin Core uses accurate counting for sigops contained within redeemScripts (P2SH)
+        /// and witnessScripts (P2WSH) only. It uses legacy for sigops in scriptSigs and scriptPubkeys.
+        ///
+        /// (Note: Taproot scripts don't count toward the sigop count of the block,
+        /// nor do they have CHECKMULTISIG operations. This function does not count OP_CHECKSIGADD,
+        /// so do not use this to try and estimate if a Taproot script goes over the sigop budget.)
+        fn count_sigops(&self) -> usize { self.count_sigops_internal(true) }
+
+        /// Counts the sigops for this Script using legacy counting.
+        ///
+        /// In Bitcoin Core, there are two ways to count sigops, "accurate" and "legacy".
+        /// This method uses "legacy" counting. This means that OP_CHECKMULTISIG and its
+        /// verify variant count for 20 sigops.
+        ///
+        /// Bitcoin Core uses legacy counting for sigops contained within scriptSigs and
+        /// scriptPubkeys. It uses accurate for redeemScripts (P2SH) and witnessScripts (P2WSH).
+        ///
+        /// (Note: Taproot scripts don't count toward the sigop count of the block,
+        /// nor do they have CHECKMULTISIG operations. This function does not count OP_CHECKSIGADD,
+        /// so do not use this to try and estimate if a Taproot script goes over the sigop budget.)
+        fn count_sigops_legacy(&self) -> usize { self.count_sigops_internal(false) }
+
+        /// Checks whether a script is push only.
+        ///
+        /// Note: `OP_RESERVED` (`0x50`) and all the OP_PUSHNUM operations
+        /// are considered push operations.
+        #[inline]
+        fn is_push_only(&self) -> bool {
+            for inst in self.instructions() {
+                match inst {
+                    Err(_) => return false,
+                    Ok(Instruction::PushBytes(_)) => {}
+                    Ok(Instruction::Op(op)) if op.to_u8() <= 0x60 => {}
+                    // From Bitcoin Core
+                    // if (opcode > OP_PUSHNUM_16 (0x60)) return false
+                    Ok(Instruction::Op(_)) => return false,
+                }
+            }
+            true
+        }
+
         /// Returns an iterator over script bytes.
         #[inline]
         fn bytes(&self) -> Bytes<'_> { Bytes(self.as_bytes().iter().copied()) }
@@ -203,25 +252,6 @@ crate::internal_macros::define_extension_trait! {
                 && self.as_bytes()[24] == OP_CHECKSIG.to_u8()
         }
 
-        /// Checks whether a script is push only.
-        ///
-        /// Note: `OP_RESERVED` (`0x50`) and all the OP_PUSHNUM operations
-        /// are considered push operations.
-        #[inline]
-        fn is_push_only(&self) -> bool {
-            for inst in self.instructions() {
-                match inst {
-                    Err(_) => return false,
-                    Ok(Instruction::PushBytes(_)) => {}
-                    Ok(Instruction::Op(op)) if op.to_u8() <= 0x60 => {}
-                    // From Bitcoin Core
-                    // if (opcode > OP_PUSHNUM_16 (0x60)) return false
-                    Ok(Instruction::Op(_)) => return false,
-                }
-            }
-            true
-        }
-
         /// Checks whether a script pubkey is a bare multisig output.
         ///
         /// In a bare multisig pubkey script the keys are not hashed, the script
@@ -342,25 +372,6 @@ crate::internal_macros::define_extension_trait! {
             }
         }
 
-        /// Get redeemScript following BIP-0016 rules regarding P2SH spending.
-        ///
-        /// This does not guarantee that this represents a P2SH input [`Script`].
-        /// It merely gets the last push of the script.
-        ///
-        /// Use [`Script::is_p2sh`] on the scriptPubKey to check whether it is actually a P2SH script.
-        fn redeem_script(&self) -> Option<&Script> {
-            // Script must consist entirely of pushes.
-            if self.instructions().any(|i| i.is_err() || i.unwrap().push_bytes().is_none()) {
-                return None;
-            }
-
-            if let Some(Ok(Instruction::PushBytes(b))) = self.instructions().last() {
-                Some(Script::from_bytes(b.as_bytes()))
-            } else {
-                None
-            }
-        }
-
         /// Returns the minimum value an output with this script should have in order to be
         /// broadcastable on today’s Bitcoin network.
         #[deprecated(since = "0.32.0", note = "use `minimal_non_dust` etc. instead")]
@@ -395,36 +406,6 @@ crate::internal_macros::define_extension_trait! {
             self.minimal_non_dust_internal(dust_relay.to_sat_per_kvb_ceil())
         }
 
-        /// Counts the sigops for this Script using accurate counting.
-        ///
-        /// In Bitcoin Core, there are two ways to count sigops, "accurate" and "legacy".
-        /// This method uses "accurate" counting. This means that OP_CHECKMULTISIG and its
-        /// verify variant count for N sigops where N is the number of pubkeys used in the
-        /// multisig. However, it will count for 20 sigops if CHECKMULTISIG is not preceded by an
-        /// OP_PUSHNUM from 1 - 16 (this would be an invalid script)
-        ///
-        /// Bitcoin Core uses accurate counting for sigops contained within redeemScripts (P2SH)
-        /// and witnessScripts (P2WSH) only. It uses legacy for sigops in scriptSigs and scriptPubkeys.
-        ///
-        /// (Note: Taproot scripts don't count toward the sigop count of the block,
-        /// nor do they have CHECKMULTISIG operations. This function does not count OP_CHECKSIGADD,
-        /// so do not use this to try and estimate if a Taproot script goes over the sigop budget.)
-        fn count_sigops(&self) -> usize { self.count_sigops_internal(true) }
-
-        /// Counts the sigops for this Script using legacy counting.
-        ///
-        /// In Bitcoin Core, there are two ways to count sigops, "accurate" and "legacy".
-        /// This method uses "legacy" counting. This means that OP_CHECKMULTISIG and its
-        /// verify variant count for 20 sigops.
-        ///
-        /// Bitcoin Core uses legacy counting for sigops contained within scriptSigs and
-        /// scriptPubkeys. It uses accurate for redeemScripts (P2SH) and witnessScripts (P2WSH).
-        ///
-        /// (Note: Taproot scripts don't count toward the sigop count of the block,
-        /// nor do they have CHECKMULTISIG operations. This function does not count OP_CHECKSIGADD,
-        /// so do not use this to try and estimate if a Taproot script goes over the sigop budget.)
-        fn count_sigops_legacy(&self) -> usize { self.count_sigops_internal(false) }
-
         /// Writes the human-readable assembly representation of the script to the formatter.
         #[deprecated(since = "TBD", note = "use the script's `Display` impl instead")]
         fn fmt_asm(&self, f: &mut dyn fmt::Write) -> fmt::Result {
@@ -465,8 +446,48 @@ mod sealed {
     impl<T> Sealed for super::GenericScript<T> {}
 }
 
-crate::internal_macros::define_extension_trait! {
+internal_macros::define_extension_trait! {
     pub(crate) trait GenericScriptExtPriv<T> impl<T> for GenericScript<T> {
+        fn count_sigops_internal(&self, accurate: bool) -> usize {
+            let mut n = 0;
+            let mut pushnum_cache = None;
+            for inst in self.instructions() {
+                match inst {
+                    Ok(Instruction::Op(opcode)) => {
+                        match opcode {
+                            // p2pk, p2pkh
+                            OP_CHECKSIG | OP_CHECKSIGVERIFY => {
+                                n += 1;
+                            }
+                            OP_CHECKMULTISIG | OP_CHECKMULTISIGVERIFY => {
+                                match (accurate, pushnum_cache) {
+                                    (true, Some(pushnum)) => {
+                                        // Add the number of pubkeys in the multisig as sigop count
+                                        n += usize::from(pushnum);
+                                    }
+                                    _ => {
+                                        // MAX_PUBKEYS_PER_MULTISIG from Bitcoin Core
+                                        // https://github.com/bitcoin/bitcoin/blob/v25.0/src/script/script.h#L29-L30
+                                        n += 20;
+                                    }
+                                }
+                            }
+                            _ => {
+                                pushnum_cache = opcode.decode_pushnum();
+                            }
+                        }
+                    }
+                    Ok(Instruction::PushBytes(_)) => {
+                        pushnum_cache = None;
+                    }
+                    // In Bitcoin Core it does `if (!GetOp(pc, opcode)) break;`
+                    Err(_) => break,
+                }
+            }
+
+            n
+        }
+
         /// Iterates the script to find the last opcode.
         ///
         /// Returns `None` is the instruction is data push or if the script is empty.
@@ -476,6 +497,19 @@ crate::internal_macros::define_extension_trait! {
                 _ => None,
             }
         }
+
+        /// Iterates the script to find the last pushdata.
+        ///
+        /// Returns `None` if the instruction is an opcode or if the script is empty.
+        fn last_pushdata(&self) -> Option<&PushBytes> {
+            match self.instructions().last() {
+                // Handles op codes up to (but excluding) OP_PUSHNUM_NEG.
+                Some(Ok(Instruction::PushBytes(bytes))) => Some(bytes),
+                // OP_16 (0x60) and lower are considered "pushes" by Bitcoin Core (excl. OP_RESERVED).
+                // However we are only interested in the pushdata so we can ignore them.
+                _ => None,
+            }
+        }
     }
 }
 
@@ -517,57 +551,28 @@ internal_macros::define_extension_trait! {
 
             Amount::from_sat(sats).ok()
         }
+    }
+}
 
-        fn count_sigops_internal(&self, accurate: bool) -> usize {
-            let mut n = 0;
-            let mut pushnum_cache = None;
-            for inst in self.instructions() {
-                match inst {
-                    Ok(Instruction::Op(opcode)) => {
-                        match opcode {
-                            // p2pk, p2pkh
-                            OP_CHECKSIG | OP_CHECKSIGVERIFY => {
-                                n += 1;
-                            }
-                            OP_CHECKMULTISIG | OP_CHECKMULTISIGVERIFY => {
-                                match (accurate, pushnum_cache) {
-                                    (true, Some(pushnum)) => {
-                                        // Add the number of pubkeys in the multisig as sigop count
-                                        n += usize::from(pushnum);
-                                    }
-                                    _ => {
-                                        // MAX_PUBKEYS_PER_MULTISIG from Bitcoin Core
-                                        // https://github.com/bitcoin/bitcoin/blob/v25.0/src/script/script.h#L29-L30
-                                        n += 20;
-                                    }
-                                }
-                            }
-                            _ => {
-                                pushnum_cache = opcode.decode_pushnum();
-                            }
-                        }
-                    }
-                    Ok(Instruction::PushBytes(_)) => {
-                        pushnum_cache = None;
-                    }
-                    // In Bitcoin Core it does `if (!GetOp(pc, opcode)) break;`
-                    Err(_) => break,
-                }
+internal_macros::define_extension_trait! {
+    /// Extension functionality for the [`ScriptSig`] type.
+    pub trait ScriptSigExt impl for ScriptSig {
+        /// Get redeemScript following BIP-0016 rules regarding P2SH spending.
+        ///
+        /// This does not guarantee that this represents a P2SH input [`Script`].
+        /// It merely gets the last push of the script.
+        ///
+        /// Use [`Script::is_p2sh`] on the scriptPubKey to check whether it is actually a P2SH script.
+        fn redeem_script(&self) -> Option<&Script> {
+            // Script must consist entirely of pushes.
+            if self.instructions().any(|i| i.is_err() || i.unwrap().push_bytes().is_none()) {
+                return None;
             }
 
-            n
-        }
-
-        /// Iterates the script to find the last pushdata.
-        ///
-        /// Returns `None` if the instruction is an opcode or if the script is empty.
-        fn last_pushdata(&self) -> Option<&PushBytes> {
-            match self.instructions().last() {
-                // Handles op codes up to (but excluding) OP_PUSHNUM_NEG.
-                Some(Ok(Instruction::PushBytes(bytes))) => Some(bytes),
-                // OP_16 (0x60) and lower are considered "pushes" by Bitcoin Core (excl. OP_RESERVED).
-                // However we are only interested in the pushdata so we can ignore them.
-                _ => None,
+            if let Some(Ok(Instruction::PushBytes(b))) = self.instructions().last() {
+                Some(Script::from_bytes(b.as_bytes()))
+            } else {
+                None
             }
         }
     }
diff --git a/bitcoin/src/blockdata/script/instruction.rs b/bitcoin/src/blockdata/script/instruction.rs
index 5cdfae7e..66566967 100644
--- a/bitcoin/src/blockdata/script/instruction.rs
+++ b/bitcoin/src/blockdata/script/instruction.rs
@@ -56,9 +56,10 @@ impl Instruction<'_> {
     pub(super) fn script_serialized_len(&self) -> usize {
         match self {
             Instruction::Op(_) => 1,
-            // In a later commit this `super::ScriptBuf` will become a specific tagged
-            // script. It doesn't matter which one. But Rust insists that we pick one.
-            Instruction::PushBytes(bytes) => super::ScriptBuf::reserved_len_for_slice(bytes.len()),
+            // The use of `ScriptSigBuf` here is arbitrary. Rust insists that we pick
+            // a specific tagged script type.
+            Instruction::PushBytes(bytes) =>
+                super::ScriptSigBuf::reserved_len_for_slice(bytes.len()),
         }
     }
 
diff --git a/bitcoin/src/blockdata/script/mod.rs b/bitcoin/src/blockdata/script/mod.rs
index 2e4319df..e530223f 100644
--- a/bitcoin/src/blockdata/script/mod.rs
+++ b/bitcoin/src/blockdata/script/mod.rs
@@ -74,7 +74,7 @@ use crate::OutPoint;
 #[rustfmt::skip]                // Keep public re-exports separate.
 #[doc(inline)]
 pub use self::{
-    borrowed::{GenericScriptExt, ScriptExt},
+    borrowed::{GenericScriptExt, ScriptExt, ScriptSigExt},
     builder::Builder,
     instruction::{Instruction, Instructions, InstructionIndices},
     owned::{GenericScriptBufExt, ScriptBufExt},
@@ -82,11 +82,11 @@ pub use self::{
 };
 #[doc(inline)]
 pub use primitives::script::{
-    GenericScript, GenericScriptBuf, RedeemScriptSizeError, Script, ScriptBuf, ScriptHash, Tag,
-    WScriptHash, Whatever, WitnessScriptSizeError,
+    GenericScript, GenericScriptBuf, RedeemScriptSizeError, Script, ScriptBuf, ScriptHash,
+    ScriptSig, ScriptSigBuf, ScriptSigTag, Tag, WScriptHash, Whatever, WitnessScriptSizeError,
 };
 
-pub(crate) use self::borrowed::{GenericScriptExtPriv, ScriptExtPriv};
+pub(crate) use self::borrowed::GenericScriptExtPriv;
 pub(crate) use self::owned::GenericScriptBufExtPriv;
 
 impl_asref_push_bytes!(ScriptHash, WScriptHash);
diff --git a/bitcoin/src/blockdata/script/tests.rs b/bitcoin/src/blockdata/script/tests.rs
index 99d31519..cfb52d16 100644
--- a/bitcoin/src/blockdata/script/tests.rs
+++ b/bitcoin/src/blockdata/script/tests.rs
@@ -5,6 +5,7 @@ use hex_lit::hex;
 use super::*;
 use crate::consensus::encode::{deserialize, serialize};
 use crate::crypto::key::{PublicKey, XOnlyPublicKey};
+use crate::script::borrowed::ScriptExtPriv as _;
 use crate::script::witness_program::WitnessProgram;
 use crate::script::witness_version::WitnessVersion;
 use crate::{opcodes, Amount, FeeRate};
@@ -206,7 +207,7 @@ fn script_x_only_key() {
 #[test]
 fn script_builder() {
     // from txid 3bb5e6434c11fb93f64574af5d116736510717f2c595eb45b52c28e31622dfff which was in my mempool when I wrote the test
-    let script = Builder::new()
+    let script = Script::builder()
         .push_opcode(OP_DUP)
         .push_opcode(OP_HASH160)
         .push_slice(hex!("16e1ae70ff0fa102905d4af297f6912bda6cce19"))
@@ -774,7 +775,7 @@ fn default_dust_value() {
 #[test]
 fn script_get_sigop_count() {
     assert_eq!(
-        Builder::new()
+        Script::builder()
             .push_opcode(OP_DUP)
             .push_opcode(OP_HASH160)
             .push_slice([42; 20])
@@ -784,7 +785,7 @@ fn script_get_sigop_count() {
         0
     );
     assert_eq!(
-        Builder::new()
+        Script::builder()
             .push_opcode(OP_DUP)
             .push_opcode(OP_HASH160)
             .push_slice([42; 20])
@@ -795,7 +796,7 @@ fn script_get_sigop_count() {
         1
     );
     assert_eq!(
-        Builder::new()
+        Script::builder()
             .push_opcode(OP_DUP)
             .push_opcode(OP_HASH160)
             .push_slice([42; 20])
@@ -806,7 +807,7 @@ fn script_get_sigop_count() {
             .count_sigops(),
         1
     );
-    let multi = Builder::new()
+    let multi = Script::builder()
         .push_opcode(OP_PUSHNUM_1)
         .push_slice([3; 33])
         .push_slice([3; 33])
@@ -816,7 +817,7 @@ fn script_get_sigop_count() {
         .into_script();
     assert_eq!(multi.count_sigops(), 3);
     assert_eq!(multi.count_sigops_legacy(), 20);
-    let multi_verify = Builder::new()
+    let multi_verify = Script::builder()
         .push_opcode(OP_PUSHNUM_1)
         .push_slice([3; 33])
         .push_slice([3; 33])
@@ -827,7 +828,7 @@ fn script_get_sigop_count() {
         .into_script();
     assert_eq!(multi_verify.count_sigops(), 3);
     assert_eq!(multi_verify.count_sigops_legacy(), 20);
-    let multi_nopushnum_pushdata = Builder::new()
+    let multi_nopushnum_pushdata = Script::builder()
         .push_opcode(OP_PUSHNUM_1)
         .push_slice([3; 33])
         .push_slice([3; 33])
@@ -836,7 +837,7 @@ fn script_get_sigop_count() {
         .into_script();
     assert_eq!(multi_nopushnum_pushdata.count_sigops(), 20);
     assert_eq!(multi_nopushnum_pushdata.count_sigops_legacy(), 20);
-    let multi_nopushnum_op = Builder::new()
+    let multi_nopushnum_op = Script::builder()
         .push_opcode(OP_PUSHNUM_1)
         .push_slice([3; 33])
         .push_slice([3; 33])
diff --git a/bitcoin/src/blockdata/transaction.rs b/bitcoin/src/blockdata/transaction.rs
index 01c03309..b61b7ac9 100644
--- a/bitcoin/src/blockdata/transaction.rs
+++ b/bitcoin/src/blockdata/transaction.rs
@@ -21,7 +21,9 @@ use super::Weight;
 use crate::consensus::{self, encode, Decodable, Encodable};
 use crate::locktime::absolute::{self, Height, MedianTimePast};
 use crate::prelude::{Borrow, Vec};
-use crate::script::{Script, ScriptBuf, ScriptExt as _, ScriptExtPriv as _};
+use crate::script::{
+    GenericScriptExt as _, GenericScriptExtPriv as _, Script, ScriptBuf, ScriptExt as _,
+};
 #[cfg(doc)]
 use crate::sighash::{EcdsaSighashType, TapSighashType};
 use crate::witness::Witness;
@@ -1243,6 +1245,7 @@ mod tests {
     use super::*;
     use crate::consensus::encode::{deserialize, serialize};
     use crate::constants::WITNESS_SCALE_FACTOR;
+    use crate::script::ScriptSigBuf;
     use crate::sighash::EcdsaSighashType;
 
     const SOME_TX: &str = "0100000001a15d57094aa7a21a28cb20b59aab8fc7d1149a3bdbcddba9c622e4f5f6a99ece010000006c493046022100f93bb0e7d8db7bd46e40132d1f8242026e045f03a0efe71bbb8e3f475e970d790221009337cd7f1f929f00cc6ff01f03729b069a7c21b59b1736ddfee5db5946c5da8c0121033b9b137ee87d5a812d6f506efdd37f0affa7ffc310711c06c7f3e097c9447c52ffffffff0100e1f505000000001976a9140389035a9225b3839e2bbf32d826a1e222031fd888ac00000000";
@@ -1488,7 +1491,7 @@ mod tests {
             "c3573dbea28ce24425c59a189391937e00d255150fa973d59d61caf3a06b601d"
         );
         // changing sigs does not affect it
-        tx.inputs[0].script_sig = ScriptBuf::new();
+        tx.inputs[0].script_sig = ScriptSigBuf::new();
         assert_eq!(old_ntxid, tx.compute_ntxid());
         // changing pks does
         tx.outputs[0].script_pubkey = ScriptBuf::new();
diff --git a/bitcoin/src/lib.rs b/bitcoin/src/lib.rs
index 828ca1dc..e8d5afd7 100644
--- a/bitcoin/src/lib.rs
+++ b/bitcoin/src/lib.rs
@@ -114,7 +114,7 @@ pub mod ext {
     pub use crate::{
         block::{BlockUncheckedExt as _, BlockCheckedExt as _, HeaderExt as _},
         pow::CompactTargetExt as _,
-        script::{GenericScriptExt as _, GenericScriptBufExt as _, ScriptExt as _, ScriptBufExt as _},
+        script::{GenericScriptExt as _, GenericScriptBufExt as _, ScriptExt as _, ScriptBufExt as _, ScriptSigExt as _},
         transaction::{TxidExt as _, WtxidExt as _, OutPointExt as _, TxInExt as _, TxOutExt as _, TransactionExt as _},
         witness::WitnessExt as _,
     };
@@ -152,7 +152,7 @@ pub use primitives::{
     },
     merkle_tree::{TxMerkleNode, WitnessMerkleNode},
     pow::CompactTarget, // No `pow` module outside of `primitives`.
-    script::{Script, ScriptBuf},
+    script::{Script, ScriptBuf, ScriptSig, ScriptSigBuf},
     sequence::{self, Sequence}, // No `sequence` module outside of `primitives`.
     transaction::{OutPoint, Transaction, TxIn, TxOut, Txid, Version as TransactionVersion, Wtxid},
     witness::Witness,
diff --git a/bitcoin/src/psbt/map/input.rs b/bitcoin/src/psbt/map/input.rs
index 3a6a066e..bf8679c8 100644
--- a/bitcoin/src/psbt/map/input.rs
+++ b/bitcoin/src/psbt/map/input.rs
@@ -12,7 +12,7 @@ use crate::prelude::{btree_map, BTreeMap, Borrow, Box, ToOwned, Vec};
 use crate::psbt::map::Map;
 use crate::psbt::serialize::Deserialize;
 use crate::psbt::{error, raw, Error};
-use crate::script::ScriptBuf;
+use crate::script::{ScriptBuf, ScriptSigBuf};
 use crate::sighash::{
     EcdsaSighashType, InvalidSighashTypeError, NonStandardSighashTypeError, SighashTypeParseError,
     TapSighashType,
@@ -91,7 +91,7 @@ pub struct Input {
     pub bip32_derivation: BTreeMap<secp256k1::PublicKey, KeySource>,
     /// The finalized, fully-constructed scriptSig with signatures and any other
     /// scripts necessary for this input to pass validation.
-    pub final_script_sig: Option<ScriptBuf>,
+    pub final_script_sig: Option<ScriptSigBuf>,
     /// The finalized, fully-constructed scriptWitness with signatures and any
     /// other scripts necessary for this input to pass validation.
     pub final_script_witness: Option<Witness>,
@@ -298,7 +298,7 @@ impl Input {
             }
             PSBT_IN_FINAL_SCRIPTSIG => {
                 impl_psbt_insert_pair! {
-                    self.final_script_sig <= <raw_key: _>|<raw_value: ScriptBuf>
+                    self.final_script_sig <= <raw_key: _>|<raw_value: ScriptSigBuf>
                 }
             }
             PSBT_IN_FINAL_SCRIPTWITNESS => {
diff --git a/bitcoin/src/psbt/mod.rs b/bitcoin/src/psbt/mod.rs
index b67803ab..a0daffe9 100644
--- a/bitcoin/src/psbt/mod.rs
+++ b/bitcoin/src/psbt/mod.rs
@@ -1343,7 +1343,7 @@ mod tests {
     use crate::locktime::absolute;
     use crate::network::NetworkKind;
     use crate::psbt::serialize::{Deserialize, Serialize};
-    use crate::script::{GenericScriptBufExt as _, ScriptBuf};
+    use crate::script::{GenericScriptBufExt as _, ScriptBuf, ScriptSigBuf};
     use crate::transaction::{self, OutPoint, TxIn};
     use crate::witness::Witness;
     use crate::Sequence;
@@ -1370,7 +1370,7 @@ mod tests {
                             .unwrap(),
                         vout: 0,
                     },
-                    script_sig: ScriptBuf::new(),
+                    script_sig: ScriptSigBuf::new(),
                     sequence: Sequence::ENABLE_LOCKTIME_NO_RBF,
                     witness: Witness::default(),
                 }],
@@ -1546,7 +1546,7 @@ mod tests {
                             .unwrap(),
                         vout: 0,
                     },
-                    script_sig: ScriptBuf::new(),
+                    script_sig: ScriptSigBuf::new(),
                     sequence: Sequence::ENABLE_LOCKTIME_NO_RBF,
                     witness: Witness::default(),
                 }],
@@ -1617,7 +1617,7 @@ mod tests {
                         .unwrap(),
                     vout: 1,
                 },
-                script_sig: ScriptBuf::from_hex_no_length_prefix(
+                script_sig: ScriptSigBuf::from_hex_no_length_prefix(
                     "160014be18d152a9b012039daf3da7de4f53349eecb985",
                 )
                 .unwrap(),
@@ -1668,7 +1668,7 @@ mod tests {
             unsigned_tx: {
                 let mut unsigned = tx.clone();
                 unsigned.inputs[0].previous_output.txid = tx.compute_txid();
-                unsigned.inputs[0].script_sig = ScriptBuf::new();
+                unsigned.inputs[0].script_sig = ScriptSigBuf::new();
                 unsigned.inputs[0].witness = Witness::default();
                 unsigned
             },
@@ -1797,7 +1797,7 @@ mod tests {
                                 txid: "f61b1742ca13176464adb3cb66050c00787bb3a4eead37e985f2df1e37718126".parse().unwrap(),
                                 vout: 0,
                             },
-                            script_sig: ScriptBuf::new(),
+                            script_sig: ScriptSigBuf::new(),
                             sequence: Sequence::ENABLE_LOCKTIME_NO_RBF,
                             witness: Witness::default(),
                         }
@@ -1829,7 +1829,7 @@ mod tests {
                                         txid: "e567952fb6cc33857f392efa3a46c995a28f69cca4bb1b37e0204dab1ec7a389".parse().unwrap(),
                                         vout: 1,
                                     },
-                                    script_sig: ScriptBuf::from_hex_no_length_prefix("160014be18d152a9b012039daf3da7de4f53349eecb985").unwrap(),
+                                    script_sig: ScriptSigBuf::from_hex_no_length_prefix("160014be18d152a9b012039daf3da7de4f53349eecb985").unwrap(),
                                     sequence: Sequence::MAX,
                                     witness: Witness::from_slice(&[
                                         hex!("304402202712be22e0270f394f568311dc7ca9a68970b8025fdd3b240229f07f8a5f3a240220018b38d7dcd314e734c9276bd6fb40f673325bc4baa144c800d2f2f02db2765c01").as_slice(),
@@ -1841,7 +1841,7 @@ mod tests {
                                         txid: "b490486aec3ae671012dddb2bb08466bef37720a533a894814ff1da743aaf886".parse().unwrap(),
                                         vout: 1,
                                     },
-                                    script_sig: ScriptBuf::from_hex_no_length_prefix("160014fe3e9ef1a745e974d902c4355943abcb34bd5353").unwrap(),
+                                    script_sig: ScriptSigBuf::from_hex_no_length_prefix("160014fe3e9ef1a745e974d902c4355943abcb34bd5353").unwrap(),
                                     sequence: Sequence::MAX,
                                     witness: Witness::from_slice(&[
                                         hex!("3045022100d12b852d85dcd961d2f5f4ab660654df6eedcc794c0c33ce5cc309ffb5fce58d022067338a8e0e1725c197fb1a88af59f51e44e4255b20167c8684031c05d1f2592a01").as_slice(),
@@ -2158,7 +2158,7 @@ mod tests {
                             txid: "f61b1742ca13176464adb3cb66050c00787bb3a4eead37e985f2df1e37718126".parse().unwrap(),
                             vout: 0,
                         },
-                        script_sig: ScriptBuf::new(),
+                        script_sig: ScriptSigBuf::new(),
                         sequence: Sequence::ENABLE_LOCKTIME_NO_RBF,
                         witness: Witness::default(),
                     }
@@ -2190,7 +2190,7 @@ mod tests {
                                     txid: "e567952fb6cc33857f392efa3a46c995a28f69cca4bb1b37e0204dab1ec7a389".parse().unwrap(),
                                     vout: 1,
                                 },
-                                script_sig: ScriptBuf::from_hex_no_length_prefix("160014be18d152a9b012039daf3da7de4f53349eecb985").unwrap(),
+                                script_sig: ScriptSigBuf::from_hex_no_length_prefix("160014be18d152a9b012039daf3da7de4f53349eecb985").unwrap(),
                                 sequence: Sequence::MAX,
                                 witness: Witness::from_slice(&[
                                     hex!("304402202712be22e0270f394f568311dc7ca9a68970b8025fdd3b240229f07f8a5f3a240220018b38d7dcd314e734c9276bd6fb40f673325bc4baa144c800d2f2f02db2765c01").as_slice(),
@@ -2202,7 +2202,7 @@ mod tests {
                                     txid: "b490486aec3ae671012dddb2bb08466bef37720a533a894814ff1da743aaf886".parse().unwrap(),
                                     vout: 1,
                                 },
-                                script_sig: ScriptBuf::from_hex_no_length_prefix("160014fe3e9ef1a745e974d902c4355943abcb34bd5353").unwrap(),
+                                script_sig: ScriptSigBuf::from_hex_no_length_prefix("160014fe3e9ef1a745e974d902c4355943abcb34bd5353").unwrap(),
                                 sequence: Sequence::MAX,
                                 witness: Witness::from_slice(&[
                                     hex!("3045022100d12b852d85dcd961d2f5f4ab660654df6eedcc794c0c33ce5cc309ffb5fce58d022067338a8e0e1725c197fb1a88af59f51e44e4255b20167c8684031c05d1f2592a01").as_slice(),
diff --git a/bitcoin/tests/bip_174.rs b/bitcoin/tests/bip_174.rs
index 5f3ae395..730140db 100644
--- a/bitcoin/tests/bip_174.rs
+++ b/bitcoin/tests/bip_174.rs
@@ -13,7 +13,7 @@ use bitcoin::script::{GenericScriptBufExt as _, PushBytes};
 use bitcoin::secp256k1::Secp256k1;
 use bitcoin::{
     absolute, script, transaction, NetworkKind, OutPoint, PrivateKey, PublicKey, ScriptBuf,
-    Sequence, Transaction, TxIn, TxOut, Witness,
+    ScriptSigBuf, Sequence, Transaction, TxIn, TxOut, Witness,
 };
 
 #[track_caller]
@@ -166,7 +166,7 @@ fn create_transaction() -> Transaction {
                     txid: input_0.txid.parse().expect("failed to parse txid"),
                     vout: input_0.index,
                 },
-                script_sig: ScriptBuf::new(),
+                script_sig: ScriptSigBuf::new(),
                 sequence: Sequence::MAX, // Disable nSequence.
                 witness: Witness::default(),
             },
@@ -175,7 +175,7 @@ fn create_transaction() -> Transaction {
                     txid: input_1.txid.parse().expect("failed to parse txid"),
                     vout: input_1.index,
                 },
-                script_sig: ScriptBuf::new(),
+                script_sig: ScriptSigBuf::new(),
                 sequence: Sequence::MAX,
                 witness: Witness::default(),
             },
diff --git a/bitcoin/tests/psbt-sign-taproot.rs b/bitcoin/tests/psbt-sign-taproot.rs
index be650285..6cf1ec05 100644
--- a/bitcoin/tests/psbt-sign-taproot.rs
+++ b/bitcoin/tests/psbt-sign-taproot.rs
@@ -10,8 +10,8 @@ use bitcoin::script::ScriptExt as _;
 use bitcoin::taproot::{LeafVersion, TaprootBuilder, TaprootSpendInfo};
 use bitcoin::transaction::Version;
 use bitcoin::{
-    absolute, script, Address, Amount, Network, OutPoint, PrivateKey, Psbt, ScriptBuf, Sequence,
-    Transaction, TxIn, TxOut, Witness, XOnlyPublicKey,
+    absolute, script, Address, Amount, Network, OutPoint, PrivateKey, Psbt, ScriptBuf,
+    ScriptSigBuf, Sequence, Transaction, TxIn, TxOut, Witness, XOnlyPublicKey,
 };
 use secp256k1::{Keypair, Secp256k1, Signing};
 
@@ -212,7 +212,7 @@ fn create_psbt_for_taproot_key_path_spend(
         lock_time: absolute::LockTime::ZERO,
         inputs: vec![TxIn {
             previous_output: OutPoint { txid: prev_tx_id.parse().unwrap(), vout: 0 },
-            script_sig: ScriptBuf::new(),
+            script_sig: ScriptSigBuf::new(),
             sequence: Sequence(0xFFFFFFFF), // Ignore nSequence.
             witness: Witness::default(),
         }],
@@ -290,7 +290,7 @@ fn create_psbt_for_taproot_script_path_spend<K: Into<XOnlyPublicKey>>(
         lock_time: absolute::LockTime::ZERO,
         inputs: vec![TxIn {
             previous_output: OutPoint { txid: prev_tx_id.parse().unwrap(), vout: 0 },
-            script_sig: ScriptBuf::new(),
+            script_sig: ScriptSigBuf::new(),
             sequence: Sequence(0xFFFFFFFF), // Ignore nSequence.
             witness: Witness::default(),
         }],
diff --git a/bitcoin/tests/serde.rs b/bitcoin/tests/serde.rs
index 1ad44ae9..efa6ab00 100644
--- a/bitcoin/tests/serde.rs
+++ b/bitcoin/tests/serde.rs
@@ -33,7 +33,7 @@ use bitcoin::taproot::{self, ControlBlock, LeafVersion, TapTree, TaprootBuilder}
 use bitcoin::witness::Witness;
 use bitcoin::{
     ecdsa, transaction, Address, Amount, NetworkKind, OutPoint, PrivateKey, PublicKey, ScriptBuf,
-    Sequence, Target, Transaction, TxIn, TxOut, Txid, Work,
+    ScriptSigBuf, Sequence, Target, Transaction, TxIn, TxOut, Txid, Work,
 };
 
 #[test]
@@ -203,7 +203,7 @@ fn serde_regression_psbt() {
                     .unwrap(),
                 vout: 1,
             },
-            script_sig: ScriptBuf::from_hex_no_length_prefix(
+            script_sig: ScriptSigBuf::from_hex_no_length_prefix(
                 "160014be18d152a9b012039daf3da7de4f53349eecb985",
             )
             .unwrap(),
@@ -254,7 +254,7 @@ fn serde_regression_psbt() {
         unsigned_tx: {
             let mut unsigned = tx.clone();
             unsigned.inputs[0].previous_output.txid = tx.compute_txid();
-            unsigned.inputs[0].script_sig = ScriptBuf::new();
+            unsigned.inputs[0].script_sig = ScriptSigBuf::new();
             unsigned.inputs[0].witness = Witness::default();
             unsigned
         },
diff --git a/primitives/src/lib.rs b/primitives/src/lib.rs
index c0a60c78..1f4a31ba 100644
--- a/primitives/src/lib.rs
+++ b/primitives/src/lib.rs
@@ -74,7 +74,7 @@ pub use self::{
     block::{
         Block, Checked as BlockChecked, Unchecked as BlockUnchecked, Validation as BlockValidation,
     },
-    script::{Script, ScriptBuf},
+    script::{Script, ScriptBuf, ScriptSig, ScriptSigBuf},
     transaction::{Transaction, TxIn, TxOut},
     witness::Witness,
 };
diff --git a/primitives/src/script/mod.rs b/primitives/src/script/mod.rs
index 1e2110b0..80c16861 100644
--- a/primitives/src/script/mod.rs
+++ b/primitives/src/script/mod.rs
@@ -30,7 +30,7 @@ use crate::prelude::{Borrow, BorrowMut, Box, Cow, ToOwned, Vec};
 pub use self::{
     borrowed::GenericScript,
     owned::GenericScriptBuf,
-    tag::{Tag, Whatever},
+    tag::{Tag, ScriptSigTag, Whatever},
 };
 
 /// Placeholder doc (will be replaced in later commit)
@@ -39,6 +39,12 @@ pub type Script = GenericScript<Whatever>;
 /// Placeholder doc (will be replaced in later commit)
 pub type ScriptBuf = GenericScriptBuf<Whatever>;
 
+/// A reference to a script signature (scriptSig).
+pub type ScriptSig = GenericScript<ScriptSigTag>;
+
+/// A script signature (scriptSig).
+pub type ScriptSigBuf = GenericScriptBuf<ScriptSigTag>;
+
 /// The maximum allowed redeem script size for a P2SH output.
 pub const MAX_REDEEM_SCRIPT_SIZE: usize = 520;
 /// The maximum allowed redeem script size of the witness script.
diff --git a/primitives/src/script/tag.rs b/primitives/src/script/tag.rs
index 6383c026..94eadec3 100644
--- a/primitives/src/script/tag.rs
+++ b/primitives/src/script/tag.rs
@@ -13,3 +13,8 @@ pub trait Tag {}
 pub enum Whatever {}
 
 impl Tag for Whatever {}
+
+/// A script signature (scriptSig).
+#[derive(Clone, PartialOrd, Ord, PartialEq, Eq, Hash)]
+pub enum ScriptSigTag {}
+impl Tag for ScriptSigTag {}
diff --git a/primitives/src/transaction.rs b/primitives/src/transaction.rs
index b4693046..621bd449 100644
--- a/primitives/src/transaction.rs
+++ b/primitives/src/transaction.rs
@@ -36,7 +36,7 @@ use units::{Amount, Weight};
 #[cfg(feature = "alloc")]
 use crate::prelude::Vec;
 #[cfg(feature = "alloc")]
-use crate::script::ScriptBuf;
+use crate::script::{ScriptBuf, ScriptSigBuf};
 #[cfg(feature = "alloc")]
 use crate::witness::Witness;
 
@@ -137,7 +137,7 @@ impl Transaction {
                 .inputs
                 .iter()
                 .map(|txin| TxIn {
-                    script_sig: ScriptBuf::new(),
+                    script_sig: ScriptSigBuf::new(),
                     witness: Witness::default(),
                     ..*txin
                 })
@@ -308,7 +308,7 @@ pub struct TxIn {
     pub previous_output: OutPoint,
     /// The script which pushes values on the stack which will cause
     /// the referenced output's script to be accepted.
-    pub script_sig: ScriptBuf,
+    pub script_sig: ScriptSigBuf,
     /// The sequence number, which suggests to miners which of two
     /// conflicting transactions should be preferred, or 0xFFFFFFFF
     /// to ignore this feature. This is generally never used since
@@ -327,7 +327,7 @@ impl TxIn {
     /// An empty transaction input with the previous output as for a coinbase transaction.
     pub const EMPTY_COINBASE: TxIn = TxIn {
         previous_output: OutPoint::COINBASE_PREVOUT,
-        script_sig: ScriptBuf::new(),
+        script_sig: ScriptSigBuf::new(),
         sequence: Sequence::MAX,
         witness: Witness::new(),
     };
@@ -605,7 +605,7 @@ impl<'a> Arbitrary<'a> for TxIn {
     fn arbitrary(u: &mut Unstructured<'a>) -> arbitrary::Result<Self> {
         Ok(TxIn {
             previous_output: OutPoint::arbitrary(u)?,
-            script_sig: ScriptBuf::arbitrary(u)?,
+            script_sig: ScriptSigBuf::arbitrary(u)?,
             sequence: Sequence::arbitrary(u)?,
             witness: Witness::arbitrary(u)?,
         })
@@ -684,7 +684,7 @@ mod tests {
                 txid: Txid::from_byte_array([0xAA; 32]), // Arbitrary invalid dummy value.
                 vout: 0,
             },
-            script_sig: ScriptBuf::new(),
+            script_sig: ScriptSigBuf::new(),
             sequence: Sequence::MAX,
             witness: Witness::new(),
         };
diff --git a/primitives/tests/api.rs b/primitives/tests/api.rs
index 47646f9f..2bb22e36 100644
--- a/primitives/tests/api.rs
+++ b/primitives/tests/api.rs
@@ -18,7 +18,7 @@ use bitcoin_primitives::block::{Checked, Unchecked};
 use bitcoin_primitives::script::{self, ScriptHash, WScriptHash};
 use bitcoin_primitives::{
     absolute, block, merkle_tree, pow, relative, transaction, witness, OutPoint, Script, ScriptBuf,
-    Sequence, Transaction, TxIn, TxOut, Txid, Witness, Wtxid,
+    ScriptSig, ScriptSigBuf, Sequence, Transaction, TxIn, TxOut, Txid, Witness, Wtxid,
 };
 use hashes::sha256t;
 
@@ -44,9 +44,11 @@ struct Structs<'a> {
     h: merkle_tree::WitnessMerkleNode,
     i: pow::CompactTarget,
     j: &'a Script,
+    j3: &'a ScriptSig,
     k: ScriptHash,
     l: WScriptHash,
     m: ScriptBuf,
+    m3: ScriptSigBuf,
     n: Sequence,
     o: Transaction,
     p: TxIn,
@@ -60,6 +62,7 @@ struct Structs<'a> {
 }
 
 static SCRIPT: ScriptBuf = ScriptBuf::new();
+static SCRIPT_SIG: ScriptSigBuf = ScriptSigBuf::new();
 static BYTES: [u8; 32] = [0x00; 32];
 
 /// Public structs that derive common traits.
@@ -79,6 +82,7 @@ struct CommonTraits {
     k: ScriptHash,
     l: WScriptHash,
     m: ScriptBuf,
+    m3: ScriptSigBuf,
     n: Sequence,
     o: Transaction,
     p: TxIn,
@@ -107,6 +111,7 @@ struct Clone<'a> {
     k: ScriptHash,
     l: WScriptHash,
     m: ScriptBuf,
+    m3: ScriptSigBuf,
     n: Sequence,
     o: Transaction,
     p: TxIn,
@@ -136,6 +141,7 @@ struct Ord {
     k: ScriptHash,
     l: WScriptHash,
     m: ScriptBuf,
+    m3: ScriptSigBuf,
     n: Sequence,
     o: Transaction,
     p: TxIn,
@@ -153,7 +159,9 @@ struct Ord {
 struct Default {
     a: block::Version,
     b: &'static Script,
+    b3: &'static ScriptSig,
     c: ScriptBuf,
+    c3: ScriptSigBuf,
     d: Sequence,
     e: Witness,
 }
@@ -209,8 +217,8 @@ fn api_can_use_modules_from_crate_root() {
 fn api_can_use_types_from_crate_root() {
     use bitcoin_primitives::{
         Block, BlockHash, BlockHeader, BlockVersion, CompactTarget, OutPoint, Script, ScriptBuf,
-        Sequence, Transaction, TransactionVersion, TxIn, TxMerkleNode, TxOut, Txid, Witness,
-        WitnessCommitment, WitnessMerkleNode, Wtxid,
+        ScriptSig, ScriptSigBuf, Sequence, Transaction, TransactionVersion, TxIn, TxMerkleNode,
+        TxOut, Txid, Witness, WitnessCommitment, WitnessMerkleNode, Wtxid,
     };
 }
 
@@ -226,7 +234,8 @@ fn api_can_use_all_types_from_module_locktime() {
 #[test]
 fn api_can_use_all_types_from_module_script() {
     use bitcoin_primitives::script::{
-        RedeemScriptSizeError, Script, ScriptBuf, ScriptHash, WScriptHash, WitnessScriptSizeError,
+        RedeemScriptSizeError, Script, ScriptBuf, ScriptHash, ScriptSig, ScriptSigBuf, WScriptHash,
+        WitnessScriptSizeError,
     };
 }
 
@@ -265,9 +274,11 @@ fn api_all_non_error_types_have_non_empty_debug() {
         merkle_tree::WitnessMerkleNode::from_byte_array(BYTES);
         pow::CompactTarget::from_consensus(0x1d00_ffff);
         SCRIPT.as_script();
+        SCRIPT_SIG.as_script();
         ScriptHash::from_script(&SCRIPT).unwrap();
         WScriptHash::from_script(&SCRIPT).unwrap();
         SCRIPT.clone();
+        SCRIPT_SIG.clone();
         Sequence::arbitrary(&mut u).unwrap();
         Transaction::arbitrary(&mut u).unwrap();
         TxIn::arbitrary(&mut u).unwrap();
@@ -303,7 +314,9 @@ fn regression_default() {
     let want = Default {
         a: block::Version::NO_SOFT_FORK_SIGNALLING,
         b: Script::from_bytes(&[]),
+        b3: ScriptSig::from_bytes(&[]),
         c: ScriptBuf::from_bytes(Vec::new()),
+        c3: ScriptSigBuf::from_bytes(Vec::new()),
         d: Sequence::MAX,
         e: Witness::new(),
     };