Add option to sign with extra nonce

Add option to create an adaptor signature by signing with an extra
nonce

Author: GeneFerneau

core/src/core/transaction.rs

@@ -742,6 +742,7 @@ impl TxKernel {
 			&sig,
 			&self.msg_to_sign()?,
 			None,
+			None,
 			&pubkey,
 			Some(&pubkey),
 			false,
@@ -2400,7 +2401,7 @@ mod test {
 		let pubkey = excess.to_pubkey(&keychain.secp()).unwrap();
 
 		let excess_sig =
-			aggsig::sign_single(&keychain.secp(), &msg, &skey, None, Some(&pubkey)).unwrap();
+			aggsig::sign_single(&keychain.secp(), &msg, &skey, None, None, Some(&pubkey)).unwrap();
 
 		kernel.excess = excess;
 		kernel.excess_sig = excess_sig;

core/src/libtx/aggsig.rs

@@ -96,6 +96,7 @@ pub fn calculate_partial_sig(
 	secp: &Secp256k1,
 	sec_key: &SecretKey,
 	sec_nonce: &SecretKey,
+	sec_nonce_extra: Option<&SecretKey>,
 	nonce_sum: &PublicKey,
 	pubkey_sum: Option<&PublicKey>,
 	msg: &secp::Message,
@@ -106,7 +107,7 @@ pub fn calculate_partial_sig(
 		&msg,
 		sec_key,
 		Some(sec_nonce),
-		None,
+		sec_nonce_extra,
 		Some(nonce_sum),
 		pubkey_sum,
 		Some(nonce_sum),
@@ -179,6 +180,7 @@ pub fn verify_partial_sig(
 	secp: &Secp256k1,
 	sig: &Signature,
 	pub_nonce_sum: &PublicKey,
+	pub_nonce_extra: Option<&PublicKey>,
 	pubkey: &PublicKey,
 	pubkey_sum: Option<&PublicKey>,
 	msg: &secp::Message,
@@ -188,6 +190,7 @@ pub fn verify_partial_sig(
 		sig,
 		&msg,
 		Some(&pub_nonce_sum),
+		pub_nonce_extra,
 		pubkey,
 		pubkey_sum,
 		true,
@@ -323,7 +326,7 @@ pub fn verify_single_from_commit(
 	commit: &Commitment,
 ) -> Result<(), Error> {
 	let pubkey = commit.to_pubkey(secp)?;
-	if !verify_single(secp, sig, msg, None, &pubkey, Some(&pubkey), false) {
+	if !verify_single(secp, sig, msg, None, None, &pubkey, Some(&pubkey), false) {
 		return Err(ErrorKind::Signature("Signature validation error".to_string()).into());
 	}
 	Ok(())
@@ -391,7 +394,7 @@ pub fn verify_completed_sig(
 	pubkey_sum: Option<&PublicKey>,
 	msg: &secp::Message,
 ) -> Result<(), Error> {
-	if !verify_single(secp, sig, msg, None, pubkey, pubkey_sum, true) {
+	if !verify_single(secp, sig, msg, None, None, pubkey, pubkey_sum, true) {
 		return Err(ErrorKind::Signature("Signature validation error".to_string()).into());
 	}
 	Ok(())
@@ -414,9 +417,19 @@ pub fn sign_single(
 	msg: &Message,
 	skey: &SecretKey,
 	snonce: Option<&SecretKey>,
+	snonce_extra: Option<&SecretKey>,
 	pubkey_sum: Option<&PublicKey>,
 ) -> Result<Signature, Error> {
-	let sig = aggsig::sign_single(secp, &msg, skey, snonce, None, None, pubkey_sum, None)?;
+	let sig = aggsig::sign_single(
+		secp,
+		&msg,
+		skey,
+		snonce,
+		snonce_extra,
+		None,
+		pubkey_sum,
+		None,
+	)?;
 	Ok(sig)
 }
 
@@ -426,12 +439,20 @@ pub fn verify_single(
 	sig: &Signature,
 	msg: &Message,
 	pubnonce: Option<&PublicKey>,
+	pubnonce_extra: Option<&PublicKey>,
 	pubkey: &PublicKey,
 	pubkey_sum: Option<&PublicKey>,
 	is_partial: bool,
 ) -> bool {
 	aggsig::verify_single(
-		secp, sig, msg, pubnonce, pubkey, pubkey_sum, None, is_partial,
+		secp,
+		sig,
+		msg,
+		pubnonce,
+		pubkey,
+		pubkey_sum,
+		pubnonce_extra,
+		is_partial,
 	)
 }
 

core/src/libtx/secp_ser.rs

@@ -433,7 +433,7 @@ mod test {
 			let mut msg = [0u8; 32];
 			thread_rng().fill(&mut msg);
 			let msg = Message::from_slice(&msg).unwrap();
-			let sig = aggsig::sign_single(&secp, &msg, &sk, None, None).unwrap();
+			let sig = aggsig::sign_single(&secp, &msg, &sk, None, None, None).unwrap();
 			let mut commit = [0u8; 33];
 			commit[0] = 0x09;
 			thread_rng().fill(&mut commit[1..]);