1CfcPe7F

1pub fn sign_transaction(
2    mut tx: Transaction,
3    input_index: usize,
4    previous_script: &Script, 
5    secret_key: &SecretKey,
6    public_key: &PublicKey,
7    is_compressed: bool
8) -> Result<Transaction, Error> {
9    if input_index >= tx.input.len() {
10        return Err(Error::OutOfRange(format!("no input with index {}", input_index)));
11    }
12
13    let signature_hash = tx.signature_hash(input_index, &previous_script, 1);
14
15    let secp = Secp256k1::new();
16    let mut signature = secp.sign(&signature_hash.to_bytes().into(), &secret_key);
17    signature.normalize_s(&secp); // Doesn't seem to matter wheter I call this function or not
18
19    let mut signature = signature.serialize_der(&secp); 
20    signature.push(SigHashType::All as u8);
21
22    let ser_public_key: Vec<u8> = match is_compressed {
23        true => public_key.serialize().to_vec(),
24        false => public_key.serialize_uncompressed().to_vec(),
25    };
26
27    let script_sig = ScriptBuilder::new()
28        .push_int(signature.len() as i64)
29        .push_slice(&signature)
30        .push_int(ser_public_key.len() as i64)
31        .push_slice(&ser_public_key)
32        .into_script();
33
34    // Is safe because we checked the vec's length at the start of the function
35    tx.input[input_index].script_sig = script_sig;
36    
37    Ok(tx)
38}