jmwallet.wallet.signing

jmwallet.wallet.signing

Bitcoin transaction signing utilities for P2WPKH and P2WSH inputs.

Uses the unified transaction models from jmcore.bitcoin. The signing functions access byte-oriented properties (txid_le, sequence_bytes, version_bytes, locktime_bytes) to construct the exact BIP-143 sighash preimage.

Attributes

Transaction = ParsedTransaction module-attribute

__all__ = ['ParsedTransaction', 'Transaction', 'TransactionSigningError', 'TxInput', 'TxOutput', 'compute_sighash_segwit', 'create_p2wpkh_script_code', 'create_p2wsh_witness_stack', 'create_witness_stack', 'deserialize_transaction', 'encode_varint', 'hash256', 'read_varint', 'sign_p2wpkh_input', 'sign_p2wsh_input', 'verify_p2wpkh_signature'] module-attribute

read_varint = decode_varint module-attribute

Classes

ParsedTransaction

Parsed Bitcoin transaction with typed inputs and outputs.

Provides dual accessors for int and bytes representations of version and locktime (needed by BIP-143 sighash construction).

Source code in jmcore/src/jmcore/bitcoin.py

@dataclass
class ParsedTransaction:
    """Parsed Bitcoin transaction with typed inputs and outputs.

    Provides dual accessors for int and bytes representations of version
    and locktime (needed by BIP-143 sighash construction).
    """

    version: int
    inputs: list[TxInput]
    outputs: list[TxOutput]
    witnesses: list[list[bytes]]
    locktime: int
    has_witness: bool

    # --- bytes accessors (for BIP-143 sighash) ------------------------------

    @property
    def version_bytes(self) -> bytes:
        """Version as 4-byte little-endian bytes."""
        return struct.pack("<I", self.version)

    @property
    def locktime_bytes(self) -> bytes:
        """Locktime as 4-byte little-endian bytes."""
        return struct.pack("<I", self.locktime)

Attributes

has_witness: bool instance-attribute

inputs: list[TxInput] instance-attribute

locktime: int instance-attribute

locktime_bytes: bytes property

Locktime as 4-byte little-endian bytes.

outputs: list[TxOutput] instance-attribute

version: int instance-attribute

version_bytes: bytes property

Version as 4-byte little-endian bytes.

witnesses: list[list[bytes]] instance-attribute

TransactionSigningError

Bases: Exception

Source code in jmwallet/src/jmwallet/wallet/signing.py

class TransactionSigningError(Exception):
    pass

TxInput

Unified transaction input model.

Stores data in canonical byte form internally. Provides dual accessors for the two dominant usage patterns in the codebase:

• String pattern (RPC / human-readable): txid (big-endian hex), scriptsig_hex, scriptpubkey_hex, sequence (int).
• Bytes pattern (BIP-143 signing): txid_le (little-endian bytes), scriptsig (bytes), sequence_bytes (4-byte LE bytes).

Construction helpers

• TxInput.from_hex(txid_hex, vout, ...) — build from big-endian hex txid (the format returned by Bitcoin Core RPC).
• Direct TxInput(txid_le=..., vout=..., ...) — build from raw LE bytes (the format found inside serialised transactions).

Source code in jmcore/src/jmcore/bitcoin.py

@dataclass
class TxInput:
    """Unified transaction input model.

    Stores data in canonical byte form internally.  Provides dual accessors for
    the two dominant usage patterns in the codebase:

    * **String pattern** (RPC / human-readable): ``txid`` (big-endian hex),
      ``scriptsig_hex``, ``scriptpubkey_hex``, ``sequence`` (int).
    * **Bytes pattern** (BIP-143 signing): ``txid_le`` (little-endian bytes),
      ``scriptsig`` (bytes), ``sequence_bytes`` (4-byte LE bytes).

    Construction helpers
    --------------------
    * ``TxInput.from_hex(txid_hex, vout, ...)`` — build from big-endian hex
      txid (the format returned by Bitcoin Core RPC).
    * Direct ``TxInput(txid_le=..., vout=..., ...)`` — build from raw LE bytes
      (the format found inside serialised transactions).
    """

    # --- canonical fields (stored as-is) ------------------------------------
    txid_le: bytes  # 32-byte txid in little-endian (wire / internal format)
    vout: int
    scriptsig: bytes = b""
    sequence: int = 0xFFFFFFFF
    value: int = 0  # Optional: UTXO value (needed by tx builder / sighash)
    scriptpubkey: bytes = b""  # Optional: prevout scriptPubKey

    # --- string accessors (big-endian hex) ----------------------------------

    @property
    def txid(self) -> str:
        """Transaction ID as big-endian hex (RPC / display format)."""
        return self.txid_le[::-1].hex()

    @property
    def scriptsig_hex(self) -> str:
        """ScriptSig as hex string."""
        return self.scriptsig.hex()

    @property
    def scriptpubkey_hex(self) -> str:
        """ScriptPubKey of the prevout as hex string."""
        return self.scriptpubkey.hex()

    # --- bytes accessors (for BIP-143 sighash) ------------------------------

    @property
    def sequence_bytes(self) -> bytes:
        """Sequence as 4-byte little-endian bytes (for BIP-143 preimage)."""
        return struct.pack("<I", self.sequence)

    # --- dict-like access (backward compat during migration) ----------------

    def __getitem__(self, key: str) -> Any:
        """Allow ``inp["txid"]`` style access for backward compatibility."""
        if key == "txid":
            return self.txid
        if key == "vout":
            return self.vout
        if key == "scriptsig":
            return self.scriptsig_hex
        if key == "sequence":
            return self.sequence
        if key == "value":
            return self.value
        if key == "scriptpubkey":
            return self.scriptpubkey_hex
        raise KeyError(key)

    def get(self, key: str, default: Any = None) -> Any:
        """Allow ``inp.get("key", default)`` for backward compatibility."""
        try:
            return self[key]
        except KeyError:
            return default

    # --- factories ----------------------------------------------------------

    @classmethod
    def from_hex(
        cls,
        txid: str,
        vout: int,
        *,
        scriptsig: str = "",
        sequence: int = 0xFFFFFFFF,
        value: int = 0,
        scriptpubkey: str = "",
    ) -> TxInput:
        """Create from big-endian hex txid (the RPC / display format).

        Args:
            txid: 64-char hex string (big-endian, as returned by RPC)
            vout: Output index
            scriptsig: ScriptSig hex (default empty)
            sequence: Sequence number (default 0xFFFFFFFF)
            value: UTXO value in satoshis (optional, for tx builder)
            scriptpubkey: Prevout scriptPubKey hex (optional)
        """
        return cls(
            txid_le=bytes.fromhex(txid)[::-1],
            vout=vout,
            scriptsig=bytes.fromhex(scriptsig) if scriptsig else b"",
            sequence=sequence,
            value=value,
            scriptpubkey=bytes.fromhex(scriptpubkey) if scriptpubkey else b"",
        )

Attributes

scriptpubkey: bytes = b'' class-attribute instance-attribute

scriptpubkey_hex: str property

ScriptPubKey of the prevout as hex string.

scriptsig: bytes = b'' class-attribute instance-attribute

scriptsig_hex: str property

ScriptSig as hex string.

sequence: int = 4294967295 class-attribute instance-attribute

sequence_bytes: bytes property

Sequence as 4-byte little-endian bytes (for BIP-143 preimage).

txid: str property

Transaction ID as big-endian hex (RPC / display format).

txid_le: bytes instance-attribute

value: int = 0 class-attribute instance-attribute

vout: int instance-attribute

Functions

__getitem__(key: str) -> Any

Allow inp["txid"] style access for backward compatibility.

Source code in jmcore/src/jmcore/bitcoin.py

def __getitem__(self, key: str) -> Any:
    """Allow ``inp["txid"]`` style access for backward compatibility."""
    if key == "txid":
        return self.txid
    if key == "vout":
        return self.vout
    if key == "scriptsig":
        return self.scriptsig_hex
    if key == "sequence":
        return self.sequence
    if key == "value":
        return self.value
    if key == "scriptpubkey":
        return self.scriptpubkey_hex
    raise KeyError(key)

from_hex(txid: str, vout: int, *, scriptsig: str = '', sequence: int = 4294967295, value: int = 0, scriptpubkey: str = '') -> TxInput classmethod

Create from big-endian hex txid (the RPC / display format).

Args: txid: 64-char hex string (big-endian, as returned by RPC) vout: Output index scriptsig: ScriptSig hex (default empty) sequence: Sequence number (default 0xFFFFFFFF) value: UTXO value in satoshis (optional, for tx builder) scriptpubkey: Prevout scriptPubKey hex (optional)

Source code in jmcore/src/jmcore/bitcoin.py

@classmethod
def from_hex(
    cls,
    txid: str,
    vout: int,
    *,
    scriptsig: str = "",
    sequence: int = 0xFFFFFFFF,
    value: int = 0,
    scriptpubkey: str = "",
) -> TxInput:
    """Create from big-endian hex txid (the RPC / display format).

    Args:
        txid: 64-char hex string (big-endian, as returned by RPC)
        vout: Output index
        scriptsig: ScriptSig hex (default empty)
        sequence: Sequence number (default 0xFFFFFFFF)
        value: UTXO value in satoshis (optional, for tx builder)
        scriptpubkey: Prevout scriptPubKey hex (optional)
    """
    return cls(
        txid_le=bytes.fromhex(txid)[::-1],
        vout=vout,
        scriptsig=bytes.fromhex(scriptsig) if scriptsig else b"",
        sequence=sequence,
        value=value,
        scriptpubkey=bytes.fromhex(scriptpubkey) if scriptpubkey else b"",
    )

get(key: str, default: Any = None) -> Any

Allow inp.get("key", default) for backward compatibility.

Source code in jmcore/src/jmcore/bitcoin.py

def get(self, key: str, default: Any = None) -> Any:
    """Allow ``inp.get("key", default)`` for backward compatibility."""
    try:
        return self[key]
    except KeyError:
        return default

TxOutput

Unified transaction output model.

Stores value and script (scriptPubKey) in canonical byte form. Provides convenience accessors for hex and address representations.

Source code in jmcore/src/jmcore/bitcoin.py

@dataclass
class TxOutput:
    """Unified transaction output model.

    Stores ``value`` and ``script`` (scriptPubKey) in canonical byte form.
    Provides convenience accessors for hex and address representations.
    """

    value: int
    script: bytes  # scriptPubKey bytes

    # --- string accessors ---------------------------------------------------

    @property
    def scriptpubkey(self) -> str:
        """ScriptPubKey as hex string (backward compat alias)."""
        return self.script.hex()

    def address(self, network: str | NetworkType = "mainnet") -> str:
        """Derive address from scriptPubKey.

        Args:
            network: Network type for bech32/base58 encoding.

        Returns:
            Address string.

        Raises:
            ValueError: If scriptPubKey is an unsupported type.
        """
        return scriptpubkey_to_address(self.script, network)

    # --- dict-like access (backward compat during migration) ----------------

    def __getitem__(self, key: str) -> Any:
        """Allow ``out["value"]`` style access for backward compatibility."""
        if key == "value":
            return self.value
        if key == "scriptpubkey":
            return self.scriptpubkey
        raise KeyError(key)

    def get(self, key: str, default: Any = None) -> Any:
        """Allow ``out.get("key", default)`` for backward compatibility."""
        try:
            return self[key]
        except KeyError:
            return default

    # --- factories ----------------------------------------------------------

    @classmethod
    def from_address(
        cls,
        address: str,
        value: int,
    ) -> TxOutput:
        """Create from address string (resolves to scriptPubKey).

        Args:
            address: Bitcoin address (any supported format)
            value: Output value in satoshis
        """
        return cls(value=value, script=address_to_scriptpubkey(address))

    @classmethod
    def from_hex(cls, scriptpubkey: str, value: int) -> TxOutput:
        """Create from hex scriptPubKey.

        Args:
            scriptpubkey: ScriptPubKey as hex string
            value: Output value in satoshis
        """
        return cls(value=value, script=bytes.fromhex(scriptpubkey))

Attributes

script: bytes instance-attribute

scriptpubkey: str property

ScriptPubKey as hex string (backward compat alias).

value: int instance-attribute

Functions

__getitem__(key: str) -> Any

Allow out["value"] style access for backward compatibility.

Source code in jmcore/src/jmcore/bitcoin.py

def __getitem__(self, key: str) -> Any:
    """Allow ``out["value"]`` style access for backward compatibility."""
    if key == "value":
        return self.value
    if key == "scriptpubkey":
        return self.scriptpubkey
    raise KeyError(key)

address(network: str | NetworkType = 'mainnet') -> str

Derive address from scriptPubKey.

Args: network: Network type for bech32/base58 encoding.

Returns: Address string.

Raises: ValueError: If scriptPubKey is an unsupported type.

Source code in jmcore/src/jmcore/bitcoin.py

def address(self, network: str | NetworkType = "mainnet") -> str:
    """Derive address from scriptPubKey.

    Args:
        network: Network type for bech32/base58 encoding.

    Returns:
        Address string.

    Raises:
        ValueError: If scriptPubKey is an unsupported type.
    """
    return scriptpubkey_to_address(self.script, network)

from_address(address: str, value: int) -> TxOutput classmethod

Create from address string (resolves to scriptPubKey).

Args: address: Bitcoin address (any supported format) value: Output value in satoshis

Source code in jmcore/src/jmcore/bitcoin.py

@classmethod
def from_address(
    cls,
    address: str,
    value: int,
) -> TxOutput:
    """Create from address string (resolves to scriptPubKey).

    Args:
        address: Bitcoin address (any supported format)
        value: Output value in satoshis
    """
    return cls(value=value, script=address_to_scriptpubkey(address))

from_hex(scriptpubkey: str, value: int) -> TxOutput classmethod

Create from hex scriptPubKey.

Args: scriptpubkey: ScriptPubKey as hex string value: Output value in satoshis

Source code in jmcore/src/jmcore/bitcoin.py

@classmethod
def from_hex(cls, scriptpubkey: str, value: int) -> TxOutput:
    """Create from hex scriptPubKey.

    Args:
        scriptpubkey: ScriptPubKey as hex string
        value: Output value in satoshis
    """
    return cls(value=value, script=bytes.fromhex(scriptpubkey))

get(key: str, default: Any = None) -> Any

Allow out.get("key", default) for backward compatibility.

Source code in jmcore/src/jmcore/bitcoin.py

def get(self, key: str, default: Any = None) -> Any:
    """Allow ``out.get("key", default)`` for backward compatibility."""
    try:
        return self[key]
    except KeyError:
        return default

Functions

compute_sighash_segwit(tx: ParsedTransaction, input_index: int, script_code: bytes, value: int, sighash_type: int) -> bytes

Source code in jmwallet/src/jmwallet/wallet/signing.py

def compute_sighash_segwit(
    tx: ParsedTransaction,
    input_index: int,
    script_code: bytes,
    value: int,
    sighash_type: int,
) -> bytes:
    try:
        if input_index >= len(tx.inputs):
            raise TransactionSigningError("Input index out of range")

        hash_prevouts = hash256(
            b"".join(inp.txid_le + inp.vout.to_bytes(4, "little") for inp in tx.inputs)
        )
        hash_sequence = hash256(b"".join(inp.sequence_bytes for inp in tx.inputs))
        hash_outputs = hash256(
            b"".join(
                out.value.to_bytes(8, "little") + encode_varint(len(out.script)) + out.script
                for out in tx.outputs
            )
        )

        target_input = tx.inputs[input_index]

        preimage = (
            tx.version_bytes
            + hash_prevouts
            + hash_sequence
            + target_input.txid_le
            + target_input.vout.to_bytes(4, "little")
            + encode_varint(len(script_code))
            + script_code
            + value.to_bytes(8, "little")
            + target_input.sequence_bytes
            + hash_outputs
            + tx.locktime_bytes
            + sighash_type.to_bytes(4, "little")
        )

        return hash256(preimage)

    except Exception as e:
        raise TransactionSigningError(f"Failed to compute sighash: {e}") from e

create_p2wpkh_script_code(pubkey: bytes | str) -> bytes

Create scriptCode for P2WPKH signing (BIP143).

For P2WPKH, the scriptCode is the P2PKH script: OP_DUP OP_HASH160 <20-byte-pubkeyhash> OP_EQUALVERIFY OP_CHECKSIG

Args: pubkey: Public key bytes or hex

Returns: 25-byte scriptCode

Source code in jmcore/src/jmcore/bitcoin.py

def create_p2wpkh_script_code(pubkey: bytes | str) -> bytes:
    """
    Create scriptCode for P2WPKH signing (BIP143).

    For P2WPKH, the scriptCode is the P2PKH script:
    OP_DUP OP_HASH160 <20-byte-pubkeyhash> OP_EQUALVERIFY OP_CHECKSIG

    Args:
        pubkey: Public key bytes or hex

    Returns:
        25-byte scriptCode
    """
    if isinstance(pubkey, str):
        pubkey = bytes.fromhex(pubkey)

    pubkey_hash = hash160(pubkey)
    # OP_DUP OP_HASH160 PUSH20 <pkh> OP_EQUALVERIFY OP_CHECKSIG
    return b"\x76\xa9\x14" + pubkey_hash + b"\x88\xac"

create_p2wsh_witness_stack(signature: bytes, witness_script: bytes) -> list[bytes]

Create witness stack for P2WSH input.

For timelocked scripts (CLTV), the witness is: [signature, witness_script]

Args: signature: DER signature with sighash byte witness_script: The witness script (e.g., freeze script)

Returns: Witness stack: [signature, witness_script]

Source code in jmwallet/src/jmwallet/wallet/signing.py

def create_p2wsh_witness_stack(signature: bytes, witness_script: bytes) -> list[bytes]:
    """Create witness stack for P2WSH input.

    For timelocked scripts (CLTV), the witness is: [signature, witness_script]

    Args:
        signature: DER signature with sighash byte
        witness_script: The witness script (e.g., freeze script)

    Returns:
        Witness stack: [signature, witness_script]
    """
    return [signature, witness_script]

create_witness_stack(signature: bytes, pubkey_bytes: bytes) -> list[bytes]

Source code in jmwallet/src/jmwallet/wallet/signing.py

def create_witness_stack(signature: bytes, pubkey_bytes: bytes) -> list[bytes]:
    return [signature, pubkey_bytes]

deserialize_transaction(tx_bytes: bytes) -> ParsedTransaction

Deserialize a raw transaction for signing.

Delegates to :func:jmcore.bitcoin.parse_transaction_bytes which now returns typed TxInput / TxOutput objects with the dual-accessor API required by the signing code.

Raises: TransactionSigningError: If the transaction bytes cannot be parsed.

Source code in jmwallet/src/jmwallet/wallet/signing.py

def deserialize_transaction(tx_bytes: bytes) -> ParsedTransaction:
    """Deserialize a raw transaction for signing.

    Delegates to :func:`jmcore.bitcoin.parse_transaction_bytes` which now
    returns typed ``TxInput`` / ``TxOutput`` objects with the dual-accessor
    API required by the signing code.

    Raises:
        TransactionSigningError: If the transaction bytes cannot be parsed.
    """
    try:
        return parse_transaction_bytes(tx_bytes)
    except Exception as e:
        raise TransactionSigningError(f"Failed to parse transaction: {e}") from e

encode_varint(n: int) -> bytes

Encode integer as Bitcoin varint.

Args: n: Integer to encode

Returns: Encoded bytes

Source code in jmcore/src/jmcore/bitcoin.py

def encode_varint(n: int) -> bytes:
    """
    Encode integer as Bitcoin varint.

    Args:
        n: Integer to encode

    Returns:
        Encoded bytes
    """
    if n < 0xFD:
        return bytes([n])
    elif n <= 0xFFFF:
        return bytes([0xFD]) + struct.pack("<H", n)
    elif n <= 0xFFFFFFFF:
        return bytes([0xFE]) + struct.pack("<I", n)
    else:
        return bytes([0xFF]) + struct.pack("<Q", n)

hash256(data: bytes) -> bytes

SHA256(SHA256(data)) - Used for Bitcoin txids and block hashes.

Args: data: Input data to hash

Returns: 32-byte hash

Source code in jmcore/src/jmcore/bitcoin.py

def hash256(data: bytes) -> bytes:
    """
    SHA256(SHA256(data)) - Used for Bitcoin txids and block hashes.

    Args:
        data: Input data to hash

    Returns:
        32-byte hash
    """
    return hashlib.sha256(hashlib.sha256(data).digest()).digest()

sign_p2wpkh_input(tx: ParsedTransaction, input_index: int, script_code: bytes, value: int, private_key: PrivateKey, sighash_type: int = 1) -> bytes

Sign a P2WPKH input using coincurve.

Args: tx: The transaction to sign input_index: Index of the input to sign script_code: The scriptCode for signing (P2PKH script for P2WPKH) value: The value of the input being spent (in satoshis) private_key: coincurve PrivateKey instance sighash_type: Sighash type (default SIGHASH_ALL = 1)

Returns: DER-encoded signature with sighash type byte appended

Source code in jmwallet/src/jmwallet/wallet/signing.py

def sign_p2wpkh_input(
    tx: ParsedTransaction,
    input_index: int,
    script_code: bytes,
    value: int,
    private_key: PrivateKey,
    sighash_type: int = 1,
) -> bytes:
    """Sign a P2WPKH input using coincurve.

    Args:
        tx: The transaction to sign
        input_index: Index of the input to sign
        script_code: The scriptCode for signing (P2PKH script for P2WPKH)
        value: The value of the input being spent (in satoshis)
        private_key: coincurve PrivateKey instance
        sighash_type: Sighash type (default SIGHASH_ALL = 1)

    Returns:
        DER-encoded signature with sighash type byte appended
    """
    if sighash_type != 1:
        raise TransactionSigningError(
            f"Unsupported sighash type {sighash_type}; only SIGHASH_ALL (0x01) allowed for signing"
        )

    sighash = compute_sighash_segwit(tx, input_index, script_code, value, sighash_type)

    # Sign the pre-hashed sighash (it's already SHA256d)
    # coincurve's sign() with hasher=None skips hashing
    signature = private_key.sign(sighash, hasher=None)

    return signature + bytes([sighash_type])

sign_p2wsh_input(tx: ParsedTransaction, input_index: int, witness_script: bytes, value: int, private_key: PrivateKey, sighash_type: int = 1) -> bytes

Sign a P2WSH input using coincurve.

For P2WSH, the scriptCode in BIP143 signing is the witness script itself.

Args: tx: The transaction to sign input_index: Index of the input to sign witness_script: The witness script (e.g., timelocked freeze script) value: The value of the input being spent (in satoshis) private_key: coincurve PrivateKey instance sighash_type: Sighash type (default SIGHASH_ALL = 1)

Returns: DER-encoded signature with sighash type byte appended

Source code in jmwallet/src/jmwallet/wallet/signing.py

def sign_p2wsh_input(
    tx: ParsedTransaction,
    input_index: int,
    witness_script: bytes,
    value: int,
    private_key: PrivateKey,
    sighash_type: int = 1,
) -> bytes:
    """Sign a P2WSH input using coincurve.

    For P2WSH, the scriptCode in BIP143 signing is the witness script itself.

    Args:
        tx: The transaction to sign
        input_index: Index of the input to sign
        witness_script: The witness script (e.g., timelocked freeze script)
        value: The value of the input being spent (in satoshis)
        private_key: coincurve PrivateKey instance
        sighash_type: Sighash type (default SIGHASH_ALL = 1)

    Returns:
        DER-encoded signature with sighash type byte appended
    """
    if sighash_type != 1:
        raise TransactionSigningError(
            f"Unsupported sighash type {sighash_type}; only SIGHASH_ALL (0x01) allowed for signing"
        )

    # For P2WSH, the scriptCode is the witness script itself
    sighash = compute_sighash_segwit(tx, input_index, witness_script, value, sighash_type)

    # Sign the pre-hashed sighash (it's already SHA256d)
    signature = private_key.sign(sighash, hasher=None)

    return signature + bytes([sighash_type])

verify_p2wpkh_signature(tx: ParsedTransaction, input_index: int, script_code: bytes, value: int, signature: bytes, pubkey: bytes) -> bool

Verify a P2WPKH signature using coincurve.

Args: tx: The transaction containing the input input_index: Index of the input to verify script_code: The scriptCode (P2PKH script for P2WPKH) value: The value of the input being spent (in satoshis) signature: DER-encoded signature with sighash type byte appended pubkey: Public key bytes (compressed or uncompressed)

Returns: True if signature is valid, False otherwise

Source code in jmwallet/src/jmwallet/wallet/signing.py

def verify_p2wpkh_signature(
    tx: ParsedTransaction,
    input_index: int,
    script_code: bytes,
    value: int,
    signature: bytes,
    pubkey: bytes,
) -> bool:
    """Verify a P2WPKH signature using coincurve.

    Args:
        tx: The transaction containing the input
        input_index: Index of the input to verify
        script_code: The scriptCode (P2PKH script for P2WPKH)
        value: The value of the input being spent (in satoshis)
        signature: DER-encoded signature with sighash type byte appended
        pubkey: Public key bytes (compressed or uncompressed)

    Returns:
        True if signature is valid, False otherwise
    """
    from coincurve import PublicKey

    try:
        # Extract sighash type from last byte of signature
        if not signature:
            return False
        sighash_type = signature[-1]
        der_signature = signature[:-1]

        sighash = compute_sighash_segwit(tx, input_index, script_code, value, sighash_type)

        # Verify signature against sighash
        # coincurve verify(signature, message, hasher=None)
        public_key = PublicKey(pubkey)
        return public_key.verify(der_signature, sighash, hasher=None)
    except Exception:
        return False