f - grind_signatures

Author: jkczyz

lightning/src/ln/channel.rs

@@ -17402,19 +17402,19 @@ mod tests {
 		// 2 inputs, initiator, 2000 sat/kw feerate
 		assert_eq!(
 			estimate_v2_funding_transaction_fee(&two_inputs, &[], true, false, 2000),
-			1516,
+			if cfg!(feature = "grind_signatures") { 1512 } else { 1516 },
 		);
 
 		// higher feerate
 		assert_eq!(
 			estimate_v2_funding_transaction_fee(&two_inputs, &[], true, false, 3000),
-			2274,
+			if cfg!(feature = "grind_signatures") { 2268 } else { 2274 },
 		);
 
 		// only 1 input
 		assert_eq!(
 			estimate_v2_funding_transaction_fee(&one_input, &[], true, false, 2000),
-			972,
+			if cfg!(feature = "grind_signatures") { 970 } else { 972 },
 		);
 
 		// 0 inputs
@@ -17432,13 +17432,13 @@ mod tests {
 		// splice initiator
 		assert_eq!(
 			estimate_v2_funding_transaction_fee(&one_input, &[], true, true, 2000),
-			if cfg!(feature = "grind_signatures") { 1738 } else { 1740 },
+			if cfg!(feature = "grind_signatures") { 1736 } else { 1740 },
 		);
 
 		// splice acceptor
 		assert_eq!(
 			estimate_v2_funding_transaction_fee(&one_input, &[], false, true, 2000),
-			544,
+			if cfg!(feature = "grind_signatures") { 542 } else { 544 },
 		);
 	}
 
@@ -17463,7 +17463,7 @@ mod tests {
 
 		// positive case, inputs well over intended contribution
 		{
-			let expected_fee = if cfg!(feature = "grind_signatures") { 2282 } else { 2284 };
+			let expected_fee = if cfg!(feature = "grind_signatures") { 2278 } else { 2284 };
 			assert_eq!(
 				check_v2_funding_inputs_sufficient(
 					220_000,
@@ -17481,7 +17481,7 @@ mod tests {
 
 		// negative case, inputs clearly insufficient
 		{
-			let expected_fee = if cfg!(feature = "grind_signatures") { 1738 } else { 1740 };
+			let expected_fee = if cfg!(feature = "grind_signatures") { 1736 } else { 1740 };
 			assert_eq!(
 				check_v2_funding_inputs_sufficient(
 					220_000,
@@ -17501,7 +17501,7 @@ mod tests {
 
 		// barely covers
 		{
-			let expected_fee = if cfg!(feature = "grind_signatures") { 2282 } else { 2284 };
+			let expected_fee = if cfg!(feature = "grind_signatures") { 2278 } else { 2284 };
 			assert_eq!(
 				check_v2_funding_inputs_sufficient(
 					(300_000 - expected_fee - 20) as i64,
@@ -17519,7 +17519,7 @@ mod tests {
 
 		// higher fee rate, does not cover
 		{
-			let expected_fee = if cfg!(feature = "grind_signatures") { 2511 } else { 2513 };
+			let expected_fee = if cfg!(feature = "grind_signatures") { 2506 } else { 2513 };
 			assert_eq!(
 				check_v2_funding_inputs_sufficient(
 					298032,
@@ -17540,7 +17540,7 @@ mod tests {
 
 		// barely covers, less fees (no extra weight, not initiator)
 		{
-			let expected_fee = 1088;
+			let expected_fee = if cfg!(feature = "grind_signatures") { 1084 } else { 1088 };
 			assert_eq!(
 				check_v2_funding_inputs_sufficient(
 					(300_000 - expected_fee - 20) as i64,

lightning/src/ln/funding.rs

@@ -143,7 +143,13 @@ impl FundingTxInput {
 	/// [`TxIn::sequence`]: bitcoin::TxIn::sequence
 	/// [`set_sequence`]: Self::set_sequence
 	pub fn new_p2wpkh(prevtx: Transaction, vout: u32) -> Result<Self, ()> {
-		let witness_weight = Weight::from_wu(P2WPKH_WITNESS_WEIGHT);
+		let witness_weight = Weight::from_wu(P2WPKH_WITNESS_WEIGHT)
+			- if cfg!(feature = "grind_signatures") {
+				// Guarantees a low R signature
+				Weight::from_wu(1)
+			} else {
+				Weight::ZERO
+			};
 		FundingTxInput::new(prevtx, vout, witness_weight, Script::is_p2wpkh)
 	}
 

lightning/src/ln/interactivetxs.rs

@@ -3372,7 +3372,11 @@ mod tests {
 
 		let total_inputs: Amount = input_prevouts.iter().map(|o| o.value).sum();
 		let total_outputs: Amount = outputs.iter().map(|o| o.value).sum();
-		let fees = Amount::from_sat(1740);
+		let fees = if cfg!(feature = "grind_signatures") {
+			Amount::from_sat(1734)
+		} else {
+			Amount::from_sat(1740)
+		};
 		let common_fees = Amount::from_sat(234);
 
 		// There is leftover for change

lightning/src/util/test_utils.rs

@@ -2226,10 +2226,16 @@ impl TestWalletSource {
 					utxo.output.value,
 					EcdsaSighashType::All,
 				)?;
+				#[cfg(not(feature = "grind_signatures"))]
 				let signature = self.secp.sign_ecdsa(
 					&secp256k1::Message::from_digest(sighash.to_byte_array()),
 					&self.secret_key,
 				);
+				#[cfg(feature = "grind_signatures")]
+				let signature = self.secp.sign_ecdsa_low_r(
+					&secp256k1::Message::from_digest(sighash.to_byte_array()),
+					&self.secret_key,
+				);
 				let bitcoin_sig =
 					bitcoin::ecdsa::Signature { signature, sighash_type: EcdsaSighashType::All };
 				tx.input[i].witness =