Merge rust-bitcoin/rust-bitcoin#1066: Upgrade to secp256k1 v0.23.0

36f29d4 Upgrade to secp256k1 v0.23.0 (Tobin C. Harding)

Pull request description:

  We recently released a new version of `rust-secp256k1`, upgrade to use it.

ACKs for top commit:
  apoelstra:
    ACK 36f29d4
  Kixunil:
    ACK 36f29d4

Tree-SHA512: 46a909dec8bc59daa78acdb76824d93f4f1da0e9736cf6ca443d3bbadfa43867e720293bb7c4919cb0658e75ec59daeffea080611f0e7eed4df439ddac0305de

Author: apoelstra

Cargo.toml

@@ -36,7 +36,7 @@ rustdoc-args = ["--cfg", "docsrs"]
 [dependencies]
 bech32 = { version = "0.8.1", default-features = false }
 bitcoin_hashes = { version = "0.10.0", default-features = false }
-secp256k1 = { version = "0.22.0", default-features = false }
+secp256k1 = { version = "0.23.0", default-features = false }
 core2 = { version = "0.3.0", optional = true, default-features = false }
 
 base64 = { version = "0.13.0", optional = true }
@@ -48,7 +48,7 @@ hashbrown = { version = "0.8", optional = true }
 [dev-dependencies]
 serde_json = "<1.0.45"
 serde_test = "1"
-secp256k1 = { version = "0.22.0", features = [ "recovery", "rand-std" ] }
+secp256k1 = { version = "0.23.0", features = [ "recovery", "rand-std" ] }
 bincode = "1.3.1"
 
 [[example]]

src/consensus/encode.rs

@@ -1115,7 +1115,7 @@ mod tests {
 
             data.clear();
             data64.clear();
-            let len = thread_rng().gen_range(1, 256);
+            let len = thread_rng().gen_range(1..256);
             data.resize(len, 0u8);
             data64.resize(len, 0u64);
             let mut arr33 = [0u8; 33];

src/util/bip32.rs

@@ -590,15 +590,15 @@ impl ExtendedPrivKey {
 
         hmac_engine.input(&endian::u32_to_array_be(u32::from(i)));
         let hmac_result: Hmac<sha512::Hash> = Hmac::from_engine(hmac_engine);
-        let mut sk = secp256k1::SecretKey::from_slice(&hmac_result[..32])?;
-        sk.add_assign(&self.private_key[..])?;
+        let sk = secp256k1::SecretKey::from_slice(&hmac_result[..32]).expect("statistically impossible to hit");
+        let tweaked = sk.add_tweak(&self.private_key.into()).expect("statistically impossible to hit");
 
         Ok(ExtendedPrivKey {
             network: self.network,
             depth: self.depth + 1,
             parent_fingerprint: self.fingerprint(secp),
             child_number: i,
-            private_key: sk,
+            private_key: tweaked,
             chain_code: ChainCode::from(&hmac_result[32..])
         })
     }
@@ -731,15 +731,14 @@ impl ExtendedPubKey {
         i: ChildNumber,
     ) -> Result<ExtendedPubKey, Error> {
         let (sk, chain_code) = self.ckd_pub_tweak(i)?;
-        let mut pk = self.public_key;
-        pk.add_exp_assign(secp, &sk[..])?;
+        let tweaked = self.public_key.add_exp_tweak(secp, &sk.into())?;
 
         Ok(ExtendedPubKey {
             network: self.network,
             depth: self.depth + 1,
             parent_fingerprint: self.fingerprint(),
             child_number: i,
-            public_key: pk,
+            public_key: tweaked,
             chain_code,
         })
     }

src/util/merkleblock.rs

@@ -715,7 +715,7 @@ mod tests {
     impl PartialMerkleTree {
         /// Flip one bit in one of the hashes - this should break the authentication
         fn damage(&mut self, rng: &mut ThreadRng) {
-            let n = rng.gen_range(0, self.hashes.len());
+            let n = rng.gen_range(0..self.hashes.len());
             let bit = rng.gen::<u8>();
             let hashes = &mut self.hashes;
             let mut hash = hashes[n].into_inner();

src/util/schnorr.rs

@@ -12,7 +12,6 @@ use core::fmt;
 use crate::prelude::*;
 
 use secp256k1::{self, Secp256k1, Verification, constants};
-use crate::hashes::Hash;
 use crate::util::taproot::{TapBranchHash, TapTweakHash};
 use crate::SchnorrSighashType;
 
@@ -101,11 +100,10 @@ impl TapTweak for UntweakedPublicKey {
     /// # Returns
     /// The tweaked key and its parity.
     fn tap_tweak<C: Verification>(self, secp: &Secp256k1<C>, merkle_root: Option<TapBranchHash>) -> (TweakedPublicKey, secp256k1::Parity) {
-        let tweak_value = TapTweakHash::from_key_and_tweak(self, merkle_root).into_inner();
-        let mut output_key = self;
-        let parity = output_key.tweak_add_assign(secp, &tweak_value).expect("Tap tweak failed");
+        let tweak = TapTweakHash::from_key_and_tweak(self, merkle_root).to_scalar();
+        let (output_key, parity) = self.add_tweak(secp, &tweak).expect("Tap tweak failed");
 
-        debug_assert!(self.tweak_add_check(secp, &output_key, parity, tweak_value));
+        debug_assert!(self.tweak_add_check(secp, &output_key, parity, tweak));
         (TweakedPublicKey(output_key), parity)
     }
 
@@ -130,11 +128,11 @@ impl TapTweak for UntweakedKeyPair {
     ///
     /// # Returns
     /// The tweaked key and its parity.
-    fn tap_tweak<C: Verification>(mut self, secp: &Secp256k1<C>, merkle_root: Option<TapBranchHash>) -> TweakedKeyPair {
-        let pubkey = crate::XOnlyPublicKey::from_keypair(&self);
-        let tweak_value = TapTweakHash::from_key_and_tweak(pubkey, merkle_root).into_inner();
-        self.tweak_add_assign(secp, &tweak_value).expect("Tap tweak failed");
-        TweakedKeyPair(self)
+    fn tap_tweak<C: Verification>(self, secp: &Secp256k1<C>, merkle_root: Option<TapBranchHash>) -> TweakedKeyPair {
+        let (pubkey, _parity) = crate::XOnlyPublicKey::from_keypair(&self);
+        let tweak = TapTweakHash::from_key_and_tweak(pubkey, merkle_root).to_scalar();
+        let tweaked = self.add_xonly_tweak(secp, &tweak).expect("Tap tweak failed");
+        TweakedKeyPair(tweaked)
     }
 
     fn dangerous_assume_tweaked(self) -> TweakedKeyPair {

src/util/sighash.rs

@@ -1125,11 +1125,10 @@ mod tests {
             };
 
             // tests
-            let keypair = secp256k1::KeyPair::from_secret_key(secp, internal_priv_key);
-            let internal_key = XOnlyPublicKey::from_keypair(&keypair);
+            let keypair = secp256k1::KeyPair::from_secret_key(secp, &internal_priv_key);
+            let (internal_key, _parity) = XOnlyPublicKey::from_keypair(&keypair);
             let tweak = TapTweakHash::from_key_and_tweak(internal_key, merkle_root);
-            let mut tweaked_keypair = keypair;
-            tweaked_keypair.tweak_add_assign(secp, &tweak).unwrap();
+            let tweaked_keypair = keypair.add_xonly_tweak(secp, &tweak.to_scalar()).unwrap();
             let mut sig_msg = Vec::new();
             cache.taproot_encode_signing_data_to(
                 &mut sig_msg,

src/util/taproot.rs

@@ -7,7 +7,7 @@
 
 use crate::prelude::*;
 use crate::io;
-use secp256k1::{self, Secp256k1};
+use secp256k1::{self, Secp256k1, Scalar};
 
 use core::convert::TryFrom;
 use core::fmt;
@@ -79,6 +79,12 @@ impl TapTweakHash {
         }
         TapTweakHash::from_engine(eng)
     }
+
+    /// Converts a `TapTweakHash` into a `Scalar` ready for use with key tweaking API.
+    pub fn to_scalar(&self) -> Scalar {
+        // This is statistically extremely unlikely to panic.
+        Scalar::from_be_bytes(self.into_inner()).expect("hash value greater than curve order")
+    }
 }
 
 impl TapLeafHash {
@@ -836,12 +842,12 @@ impl ControlBlock {
             );
         }
         // compute the taptweak
-        let tweak = TapTweakHash::from_key_and_tweak(self.internal_key, Some(curr_hash));
+        let tweak = TapTweakHash::from_key_and_tweak(self.internal_key, Some(curr_hash)).to_scalar();
         self.internal_key.tweak_add_check(
             secp,
             &output_key,
             self.output_key_parity,
-            tweak.into_inner(),
+            tweak,
         )
     }
 }