// RawTxInSignature returns the serialized ECDSA signature for the input idx of
// the given transaction, with hashType appended to it.
func RawTxInSignature(tx *wire.MsgTx, idx int, subScript []byte,
hashType SigHashType, key *btcec.PrivateKey) ([]byte, error) {
parsedScript, err := parseScript(subScript)
if err != nil {
return nil, fmt.Errorf("cannot parse output script: %v", err)
}
hash := calcSignatureHash(parsedScript, hashType, tx, idx)
signature, err := key.Sign(hash)
if err != nil {
return nil, fmt.Errorf("cannot sign tx input: %s", err)
}
return append(signature.Serialize(), byte(hashType)), nil
}
