Use recover_from_prehash

contracts/ccc-btc-lock/src/entry.rs

@@ -16,13 +16,13 @@ pub fn entry() -> Result<(), Error> {
     let script = load_script()?;
     let pubkey_hash = script.args().raw_data();
     if pubkey_hash.len() != 20 {
-        return Err(Error::WrongPubkey);
+        return Err(Error::WrongPubkeyHash);
     }
 
     let mut to_be_hashed: Vec<u8> = Default::default();
-    to_be_hashed.push(BTC_PREFIX.len() as u8); // fixed value 24
     assert_eq!(BTC_PREFIX.len(), 24);
-    to_be_hashed.extend(String::from(BTC_PREFIX).into_bytes());
+    to_be_hashed.push(BTC_PREFIX.len() as u8);
+    to_be_hashed.extend(BTC_PREFIX.as_bytes());
 
     let sighash_all = generate_sighash_all()?;
     let sighash_all_hex = hex::encode(&sighash_all);
@@ -32,7 +32,7 @@ pub fn entry() -> Result<(), Error> {
     to_be_hashed.push(message1.len() as u8);
     to_be_hashed.extend(message1.into_bytes());
 
-    // double SHA-256 from bitcoin
+    // Double SHA-256 from bitcoin
     let msg = Sha256::digest(&Sha256::digest(&to_be_hashed));
 
     let witness_args = load_witness_args(0, Source::GroupInput)?;
@@ -48,7 +48,7 @@ pub fn entry() -> Result<(), Error> {
     let rec_id = sig[0];
     let rec_id = RecoveryId::try_from(rec_id).map_err(|_| Error::InvalidRecoverId)?;
     let signature = Signature::from_slice(&sig[1..]).map_err(|_| Error::WrongSignatureFormat)?;
-    let recovered_key = VerifyingKey::recover_from_msg(&msg, &signature, rec_id)
+    let recovered_key = VerifyingKey::recover_from_prehash(&msg, &signature, rec_id)
         .map_err(|_| Error::CanNotRecover)?;
     // TODO: double check its format
     let recovered_key_bytes = recovered_key.to_sec1_bytes();

contracts/ccc-btc-lock/src/error.rs

@@ -9,7 +9,7 @@ pub enum Error {
     Encoding,
     Unknown = 30,
     WrongWitnessArgs,
-    WrongPubkey,
+    WrongPubkeyHash,
     PubkeyHashMismatched,
     WrongSignatureFormat,
     InvalidRecoverId,