compute_sighash (Func)

Compute the signature hash (sighash) for a specific transaction input.

This mirrors the digest the node computes when validating a signature for the input, without signing it. Useful for external/HSM signers, multisig assembly, or verifying a signature against a precomputed digest. With the defaults (Schnorr, SighashType.All) the resulting hash can be signed with sign_script_hash. For any other sighash_type, or with ecdsa=True, sign the digest externally and assemble the signature script yourself — the signature followed by the hashtype byte matching the digest — because sign_script_hash always signs Schnorr and appends the All hashtype byte.

Every transaction input must have an attached UTXO entry, as the sighash commits to each input's script public key and amount.

PARAMETER	DESCRIPTION
tx	The transaction containing the input. TYPE: Transaction
input_index	The index of the input to compute the sighash for. TYPE: int
sighash_type	The signature hash type (default: All). TYPE: str | SighashType | None DEFAULT: None
ecdsa	Compute the ECDSA variant of the sighash instead of Schnorr (an additional hash round over the Schnorr digest). TYPE: bool DEFAULT: False

RETURNS	DESCRIPTION
Hash	The signature hash for the input. TYPE: Hash

RAISES	DESCRIPTION
Exception	If the input index is out of bounds or the transaction's inputs are missing UTXO entries.