Use Message::from_digest

We have a new API function available with recent version of `secp256k1`
to create a `Message` directly from a sighash byte array.

Use `Message::from_digest(sighash.to_byte_array())` to construct
messages ready to sign.

bitcoin/examples/sighash.rs

@@ -45,9 +45,7 @@ fn compute_sighash_p2wpkh(raw_tx: &[u8], inp_idx: usize, value: u64) {
         .p2wpkh_signature_hash(inp_idx, &spk, Amount::from_sat(value), sig.hash_ty)
         .expect("failed to compute sighash");
     println!("Segwit p2wpkh sighash: {:x}", sighash);
-    // TODO: After upgrade of secp change this to Message::from_digest(sighash.to_byte_array()).
+    let msg = secp256k1::Message::from_digest(sighash.to_byte_array());
-    let msg = secp256k1::Message::from_digest_slice(sighash.as_byte_array())
-        .expect("sighash is 32 bytes long");
     println!("Message is {:x}", msg);
     let secp = secp256k1::Secp256k1::verification_only();
     secp.verify_ecdsa(&msg, &sig.sig, &pk.inner).unwrap();

bitcoin/examples/taproot-psbt.rs

@@ -739,9 +739,7 @@ fn sign_psbt_taproot(
         Some(_) => keypair, // no tweak for script spend
     };
 
-    // TODO: After upgrade of secp change this to Message::from_digest(sighash.to_byte_array()).
+    let msg = secp256k1::Message::from_digest(hash.to_byte_array());
-    let msg = secp256k1::Message::from_digest_slice(hash.as_byte_array())
-        .expect("tap sighash is 32 bytes long");
     let sig = secp.sign_schnorr(&msg, &keypair);
 
     let final_signature = taproot::Signature { sig, hash_ty };

bitcoin/src/crypto/sighash.rs

@@ -1762,9 +1762,7 @@ mod tests {
                 .taproot_signature_hash(tx_ind, &Prevouts::All(&utxos), None, None, hash_ty)
                 .unwrap();
 
-            // TODO: After upgrade of secp change this to Message::from_digest(sighash.to_byte_array()).
+            let msg = secp256k1::Message::from_digest(sighash.to_byte_array());
-            let msg = secp256k1::Message::from_digest_slice(sighash.as_byte_array())
-                .expect("sighash is 32 bytes long");
             let key_spend_sig = secp.sign_schnorr_with_aux_rand(&msg, &tweaked_keypair, &[0u8; 32]);
 
             assert_eq!(expected.internal_pubkey, internal_key);

bitcoin/src/psbt/mod.rs

@@ -405,56 +405,31 @@ impl Psbt {
         match self.output_type(input_index)? {
             Bare => {
                 let sighash = cache.legacy_signature_hash(input_index, spk, hash_ty.to_u32())?;
-                // TODO: After upgrade of secp change this to Message::from_digest(sighash.to_byte_array()).
+                Ok((Message::from_digest(sighash.to_byte_array()), hash_ty))
-                Ok((
-                    Message::from_digest_slice(sighash.as_byte_array())
-                        .expect("sighash is 32 bytes long"),
-                    hash_ty,
-                ))
             }
             Sh => {
                 let script_code =
                     input.redeem_script.as_ref().ok_or(SignError::MissingRedeemScript)?;
                 let sighash =
                     cache.legacy_signature_hash(input_index, script_code, hash_ty.to_u32())?;
-                // TODO: After upgrade of secp change this to Message::from_digest(sighash.to_byte_array()).
+                Ok((Message::from_digest(sighash.to_byte_array()), hash_ty))
-                Ok((
-                    Message::from_digest_slice(sighash.as_byte_array())
-                        .expect("sighash is 32 bytes long"),
-                    hash_ty,
-                ))
             }
             Wpkh => {
                 let sighash = cache.p2wpkh_signature_hash(input_index, spk, utxo.value, hash_ty)?;
-                // TODO: After upgrade of secp change this to Message::from_digest(sighash.to_byte_array()).
+                Ok((Message::from_digest(sighash.to_byte_array()), hash_ty))
-                Ok((
-                    Message::from_digest_slice(sighash.as_byte_array())
-                        .expect("sighash is 32 bytes long"),
-                    hash_ty,
-                ))
             }
             ShWpkh => {
                 let redeem_script = input.redeem_script.as_ref().expect("checked above");
                 let sighash =
                     cache.p2wpkh_signature_hash(input_index, redeem_script, utxo.value, hash_ty)?;
-                // TODO: After upgrade of secp change this to Message::from_digest(sighash.to_byte_array()).
+                Ok((Message::from_digest(sighash.to_byte_array()), hash_ty))
-                Ok((
-                    Message::from_digest_slice(sighash.as_byte_array())
-                        .expect("sighash is 32 bytes long"),
-                    hash_ty,
-                ))
             }
             Wsh | ShWsh => {
                 let witness_script =
                     input.witness_script.as_ref().ok_or(SignError::MissingWitnessScript)?;
                 let sighash =
                     cache.p2wsh_signature_hash(input_index, witness_script, utxo.value, hash_ty)?;
-                // TODO: After upgrade of secp change this to Message::from_digest(sighash.to_byte_array()).
+                Ok((Message::from_digest(sighash.to_byte_array()), hash_ty))
-                Ok((
-                    Message::from_digest_slice(sighash.as_byte_array())
-                        .expect("sighash is 32 bytes long"),
-                    hash_ty,
-                ))
             }
             Tr => {
                 // This PSBT signing API is WIP, taproot to come shortly.

bitcoin/src/sign_message.rs

@@ -131,10 +131,7 @@ mod message_signing {
             secp_ctx: &secp256k1::Secp256k1<C>,
             msg_hash: sha256d::Hash,
         ) -> Result<PublicKey, MessageSignatureError> {
-            // TODO: After upgrade of secp change this to Message::from_digest(sighash.to_byte_array()).
+            let msg = secp256k1::Message::from_digest(msg_hash.to_byte_array());
-            let msg = secp256k1::Message::from_digest_slice(msg_hash.as_byte_array())
-                .expect("sh256d hash is 32 bytes long");
-
             let pubkey = secp_ctx.recover_ecdsa(&msg, &self.signature)?;
             Ok(PublicKey { inner: pubkey, compressed: self.compressed })
         }
@@ -231,10 +228,7 @@ mod tests {
         let secp = secp256k1::Secp256k1::new();
         let message = "rust-bitcoin MessageSignature test";
         let msg_hash = super::signed_msg_hash(message);
-        // TODO: After upgrade of secp change this to Message::from_digest(sighash.to_byte_array()).
+        let msg = secp256k1::Message::from_digest(msg_hash.to_byte_array());
-        let msg = secp256k1::Message::from_digest_slice(msg_hash.as_byte_array())
-            .expect("sh256d hash is 32 bytes long");
-
         let privkey = secp256k1::SecretKey::new(&mut secp256k1::rand::thread_rng());
         let secp_sig = secp.sign_ecdsa_recoverable(&msg, &privkey);
         let signature = super::MessageSignature { signature: secp_sig, compressed: true };