Update rust-secp256k1 to add ecdsa-adaptor/schnorr

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "secp256k1"
-version = "0.19.0"
+version = "0.19.0-adaptor.0"
 authors = [ "Dawid Ciężarkiewicz <[email protected]>",
             "Andrew Poelstra <[email protected]>" ]
 license = "CC0-1.0"

src/bip340.rs

@@ -94,6 +94,14 @@ impl Signature {
             _ => Err(InvalidSignature),
         }
     }
+
+    /// Decompose a bip340 signature into a nonce and a secret key
+    pub fn decompose(&self) -> Result<(PublicKey, SecretKey), Error> {
+        Ok((
+            PublicKey::from_slice(&self.0[0..32])?,
+            SecretKey::from_slice(&self.0[32..64])?,
+        ))
+    }
 }
 
 impl PublicKey {
@@ -192,6 +200,7 @@ impl<C: Signing> Secp256k1<C> {
         &self,
         msg: &Message,
         sk: &SecretKey,
+        nonce_fn: ffi::SchnorrNonceFn,
         nonce_data: *const ffi::types::c_void,
     ) -> Result<Signature, Error> {
         unsafe {
@@ -209,7 +218,7 @@ impl<C: Signing> Secp256k1<C> {
                     sig.as_mut_c_ptr(),
                     msg.as_c_ptr(),
                     &keypair,
-                    ffi::secp256k1_nonce_function_bip340,
+                    nonce_fn,
                     nonce_data
                 )
             );
@@ -224,7 +233,9 @@ impl<C: Signing> Secp256k1<C> {
         msg: &Message,
         sk: &SecretKey,
     ) -> Result<Signature, Error> {
-        self.bip340_sign_helper(msg, sk, ptr::null())
+        unsafe {
+            self.bip340_sign_helper(msg, sk, ffi::secp256k1_nonce_function_bip340, ptr::null())
+        }
     }
 
     /// Create a BIP340 signature using the given auxiliary random data.
@@ -234,7 +245,14 @@ impl<C: Signing> Secp256k1<C> {
         sk: &SecretKey,
         aux_rand: &[u8; 32],
     ) -> Result<Signature, Error> {
-        self.bip340_sign_helper(msg, sk, aux_rand.as_c_ptr() as *const ffi::types::c_void)
+        unsafe {
+            self.bip340_sign_helper(
+                msg,
+                sk,
+                ffi::secp256k1_nonce_function_bip340,
+                aux_rand.as_c_ptr() as *const ffi::types::c_void,
+            )
+        }
     }
 
     /// Create a bip340 signature using the given random number generator to
@@ -249,7 +267,55 @@ impl<C: Signing> Secp256k1<C> {
     ) -> Result<Signature, Error> {
         let mut aux = [0u8; 32];
         rng.fill_bytes(&mut aux);
-        self.bip340_sign_helper(msg, sk, aux.as_c_ptr() as *const ffi::types::c_void)
+        unsafe {
+            self.bip340_sign_helper(
+                msg,
+                sk,
+                ffi::secp256k1_nonce_function_bip340,
+                aux.as_c_ptr() as *const ffi::types::c_void,
+            )
+        }
+    }
+
+    /// Create a bip340 signature using the provided nonce.
+    pub fn bip340_sign_with_nonce(
+        &self,
+        msg: &Message,
+        sk: &SecretKey,
+        nonce: &SecretKey,
+    ) -> Result<Signature, Error> {
+        self.bip340_sign_helper(
+            msg,
+            sk,
+            ffi::constant_nonce_fn,
+            nonce.as_c_ptr() as *const ffi::types::c_void,
+        )
+    }
+
+    /// Computes a point fo a Schnorr signature.
+    pub fn schnorr_compute_sig_point(
+        &self,
+        msg: &Message,
+        nonce: &PublicKey,
+        pubkey: &PublicKey,
+    ) -> Result<::key::PublicKey, Error> {
+        unsafe {
+            let mut sigpoint = ffi::PublicKey::new();
+
+            let ret = ffi::secp256k1_schnorrsig_compute_sigpoint(
+                self.ctx,
+                &mut sigpoint,
+                msg.as_c_ptr(),
+                nonce.as_c_ptr(),
+                pubkey.as_c_ptr(),
+            );
+
+            if ret == 0 {
+                return Err(Error::InvalidPublicKey);
+            }
+
+            Ok(::key::PublicKey::from(sigpoint))
+        }
     }
 
     /// Verify a BIP340 signature.

src/constants.rs

@@ -40,6 +40,12 @@ pub const BIP340_SIGNATURE_SIZE: usize = 64;
 /// Size of a x-only public key
 pub const BIP340_PUBLIC_KEY_SIZE: usize = 32;
 
+/// Size of an adaptor signature
+pub const ADAPTOR_SIGNATURE_SIZE: usize = 65;
+
+/// Size of an adaptor proof
+pub const ADAPTOR_PROOF_SIZE: usize = 97;
+
 /// Size of a key pair
 pub const KEY_PAIR_SIZE: usize = 96;