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rust-bitcoin-unsafe-fast
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Add method to push an ECDSA sig + sighash type byte on a witness 

We do this all over the place in rust-lightning, and its probably
the most common thing to do with a `Witness` so I figured I'd
upstream the util method to do this. It also avoids an allocation
compared to the naive approach of `SerializedSignature.to_vec()`
with two pushes, which is nice.
This commit is contained in:
Matt Corallo 2022-05-05 03:27:28 +00:00
parent 23fe753f0f
commit 0ab5eeac81
1 changed files with 29 additions and 0 deletions
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29
src/blockdata/witness.rs
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@ -3,10 +3,12 @@
//! This module contains the [`Witness`] struct and related methods to operate on it //! This module contains the [`Witness`] struct and related methods to operate on it
//! //!
use blockdata::transaction::EcdsaSighashType;
use consensus::encode::{Error, MAX_VEC_SIZE}; use consensus::encode::{Error, MAX_VEC_SIZE};
use consensus::{Decodable, Encodable, WriteExt}; use consensus::{Decodable, Encodable, WriteExt};
use io::{self, Read, Write}; use io::{self, Read, Write};
use prelude::*; use prelude::*;
use secp256k1::ecdsa;
use VarInt; use VarInt;
#[cfg(feature = "serde")] #[cfg(feature = "serde")]
@ -211,6 +213,17 @@ impl Witness {
self.content[end_varint..].copy_from_slice(new_element); self.content[end_varint..].copy_from_slice(new_element);
} }
/// Pushes a DER-encoded ECDSA signature with a signature hash type as a new element on the
/// witness, requires an allocation.
pub fn push_bitcoin_signature(&mut self, signature: &ecdsa::SerializedSignature, hash_type: EcdsaSighashType) {
// Note that a maximal length ECDSA signature is 72 bytes, plus the sighash type makes 73
let mut sig = [0; 73];
sig[..signature.len()].copy_from_slice(&signature);
sig[signature.len()] = hash_type as u8;
self.push(&sig[..signature.len() + 1]);
}
fn element_at(&self, index: usize) -> Option<&[u8]> { fn element_at(&self, index: usize) -> Option<&[u8]> {
let varint = VarInt::consensus_decode(&self.content[index..]).ok()?; let varint = VarInt::consensus_decode(&self.content[index..]).ok()?;
let start = index + varint.len(); let start = index + varint.len();
@ -289,10 +302,12 @@ impl<'de> serde::Deserialize<'de> for Witness {
#[cfg(test)] #[cfg(test)]
mod test { mod test {
use blockdata::transaction::EcdsaSighashType;
use blockdata::witness::Witness; use blockdata::witness::Witness;
use consensus::{deserialize, serialize}; use consensus::{deserialize, serialize};
use hashes::hex::{FromHex, ToHex}; use hashes::hex::{FromHex, ToHex};
use Transaction; use Transaction;
use secp256k1::ecdsa;
#[test] #[test]
fn test_push() { fn test_push() {
@ -321,6 +336,20 @@ mod test {
assert_eq!(witness.second_to_last(), Some(&[0u8][..])); assert_eq!(witness.second_to_last(), Some(&[0u8][..]));
} }
#[test]
fn test_push_ecdsa_sig() {
// The very first signature in block 734,958
let sig_bytes =
Vec::from_hex("304402207c800d698f4b0298c5aac830b822f011bb02df41eb114ade9a6702f364d5e39c0220366900d2a60cab903e77ef7dd415d46509b1f78ac78906e3296f495aa1b1b541");
let sig = ecdsa::Signature::from_der(&sig_bytes.unwrap()).unwrap();
let mut witness = Witness::default();
witness.push_bitcoin_signature(&sig.serialize_der(), EcdsaSighashType::All);
let expected_witness = vec![Vec::from_hex(
"304402207c800d698f4b0298c5aac830b822f011bb02df41eb114ade9a6702f364d5e39c0220366900d2a60cab903e77ef7dd415d46509b1f78ac78906e3296f495aa1b1b54101")
.unwrap()];
assert_eq!(witness.to_vec(), expected_witness);
}
#[test] #[test]
fn test_witness() { fn test_witness() {
let w0 = let w0 =