Add low_r signature grinding

[rust-lightning] / lightning / src / util / crypto.rs

diff --git a/lightning/src/util/crypto.rs b/lightning/src/util/crypto.rs
index f8a3f847d4348e5cbe13033fef25645125cdf6d4..300ddacb020566dac6fc77ac537077918b76e925 100644 (file)
--- a/lightning/src/util/crypto.rs
+++ b/lightning/src/util/crypto.rs
@@ -1,6 +1,7 @@
 use bitcoin::hashes::{Hash, HashEngine};
 use bitcoin::hashes::hmac::{Hmac, HmacEngine};
 use bitcoin::hashes::sha256::Hash as Sha256;
+use bitcoin::secp256k1::{Message, Secp256k1, SecretKey, Signature, Signing};
 
 macro_rules! hkdf_extract_expand {
        ($salt: expr, $ikm: expr) => {{
@@ -36,3 +37,12 @@ pub fn hkdf_extract_expand_twice(salt: &[u8], ikm: &[u8]) -> ([u8; 32], [u8; 32]
 pub fn hkdf_extract_expand_thrice(salt: &[u8], ikm: &[u8]) -> ([u8; 32], [u8; 32], [u8; 32]) {
        hkdf_extract_expand!(salt, ikm, 3)
 }
+
+#[inline]
+pub fn sign<C: Signing>(ctx: &Secp256k1<C>, msg: &Message, sk: &SecretKey) -> Signature {
+       #[cfg(feature = "grind_signatures")]
+       let sig = ctx.sign_low_r(msg, sk);
+       #[cfg(not(feature = "grind_signatures"))]
+       let sig = ctx.sign(msg, sk);
+       sig
+}