Merge rust-bitcoin/rust-bitcoin#1577: Re-name hash inner/byte methods

161273b209 Re-name hash inner/byte methods (Tobin C. Harding)
324b6f264b Use `into` for hash argument (Tobin C. Harding)

Pull request description:

  Currently we have an associated type on hash types `Inner` with accompanying methods `into_inner`, `from_inner`, `as_inner`. Also, we provide a way to create new wrapped hash types. The use of 'inner' becomes ambiguous with the addition of wrapped types because the inner could be the inner hash type or the `Inner` byte array of the inner wrapped hash type.

  In an effort to make the API more clear and uniform do the following:

  - Rename `Inner` -> `Bytes`
  - Rename `*_inner` -> `*_byte_array`
  - Rename the inner hash to/from methods to `*_raw_hash`

  Correct method prefix `into_` -> `to_` because theses methods convert owned `Copy` types.

  Add the trait Bound `Copy` to the `Bytes` type because we rely on this trait bound for the conversion methods to be correctly named according to convention.

  Because of the dependency hole created by `secp256k1` this patch changes the secp dependency to a git tag dependency that includes changes to the hashes calls required so that we can get green lights on CI in this repo.

  Fix: #1554

ACKs for top commit:
  Kixunil:
    ACK 161273b209
  apoelstra:
    ACK 161273b209

Tree-SHA512: b51b851a1855e6a26a7ef8ccb9f554723d4cc39b368812703587a50e81e7ab49714a81696af0be743b947f09e1fca227a5331b6735912c5b0d5cd0178905f006

bitcoin/Cargo.toml

@@ -37,7 +37,7 @@ rustdoc-args = ["--cfg", "docsrs"]
 bitcoin-internals = { path = "../internals" }
 bech32 = { version = "0.9.0", default-features = false }
 bitcoin_hashes = { version = "0.11.0", default-features = false }
-secp256k1 = { version = "0.25.0", default-features = false, features = ["bitcoin_hashes"] }
+secp256k1 = { git = "https://github.com/rust-bitcoin/rust-secp256k1", tag = "2023-02-01--fix-hashes", default-features = false, features = ["bitcoin_hashes"] }
 hex_lit = "0.1.1"
 
 base64 = { version = "0.13.0", optional = true }
@@ -50,7 +50,7 @@ actual-serde = { package = "serde", version = "1.0.103", default-features = fals
 serde_json = "1.0.0"
 serde_test = "1.0.19"
 serde_derive = "1.0.103"
-secp256k1 = { version = "0.25.0", features = ["recovery"] }
+secp256k1 = { git = "https://github.com/rust-bitcoin/rust-secp256k1", tag = "2023-02-01--fix-hashes", features = ["recovery"] }
 bincode = "1.3.1"
 
 [target.'cfg(mutate)'.dev-dependencies]

bitcoin/examples/taproot-psbt.rs

@@ -82,11 +82,10 @@ use bitcoin::bip32::{ChildNumber, DerivationPath, ExtendedPrivKey, ExtendedPubKe
 use bitcoin::consensus::encode;
 use bitcoin::constants::COIN_VALUE;
 use bitcoin::crypto::taproot;
-use bitcoin::hashes::Hash;
 use bitcoin::key::{TapTweak, XOnlyPublicKey};
 use bitcoin::opcodes::all::{OP_CHECKSIG, OP_CLTV, OP_DROP};
 use bitcoin::psbt::{self, Input, Output, Psbt, PsbtSighashType};
-use bitcoin::secp256k1::{Message, Secp256k1};
+use bitcoin::secp256k1::Secp256k1;
 use bitcoin::sighash::{self, TapSighashType, SighashCache};
 use bitcoin::taproot::{
     LeafVersion, TapLeafHash, TapSighash, TaprootBuilder, TaprootSpendInfo,
@@ -745,7 +744,7 @@ fn sign_psbt_taproot(
         Some(_) => keypair, // no tweak for script spend
     };
 
-    let sig = secp.sign_schnorr(&Message::from_slice(&hash.into_inner()[..]).unwrap(), &keypair);
+    let sig = secp.sign_schnorr(&hash.into(), &keypair);
 
     let final_signature = taproot::Signature { sig, hash_ty };
 

bitcoin/src/address.rs

@@ -435,13 +435,12 @@ impl Payload {
     /// Constructs a [Payload] from an output script (`scriptPubkey`).
     pub fn from_script(script: &Script) -> Result<Payload, Error> {
         Ok(if script.is_p2pkh() {
-            let mut hash_inner = [0u8; 20];
+            let bytes = script.as_bytes()[3..23].try_into().expect("statically 20B long");
-            hash_inner.copy_from_slice(&script.as_bytes()[3..23]);
+            Payload::PubkeyHash(PubkeyHash::from_byte_array(bytes))
-            Payload::PubkeyHash(PubkeyHash::from_inner(hash_inner))
+
         } else if script.is_p2sh() {
-            let mut hash_inner = [0u8; 20];
+            let bytes = script.as_bytes()[2..22].try_into().expect("statically 20B long");
-            hash_inner.copy_from_slice(&script.as_bytes()[2..22]);
+            Payload::ScriptHash(ScriptHash::from_byte_array(bytes))
-            Payload::ScriptHash(ScriptHash::from_inner(hash_inner))
         } else if script.is_witness_program() {
             let opcode = script.first_opcode().expect("witness_version guarantees len() > 4");
 
@@ -959,9 +958,9 @@ impl Address {
         let payload = self.payload.inner_prog_as_bytes();
         let xonly_pubkey = XOnlyPublicKey::from(pubkey.inner);
 
-        (*pubkey_hash.as_inner() == *payload)
+        (*pubkey_hash.as_byte_array() == *payload)
             || (xonly_pubkey.serialize() == *payload)
-            || (*segwit_redeem_hash(&pubkey_hash).as_inner() == *payload)
+            || (*segwit_redeem_hash(&pubkey_hash).as_byte_array() == *payload)
     }
 
     /// Returns true if the supplied xonly public key can be used to derive the address.

bitcoin/src/bip152.rs

@@ -221,8 +221,8 @@ impl HeaderAndShortIds {
             } else {
                 short_ids.push(ShortId::with_siphash_keys(
                     &match version {
-                        1 => tx.txid().as_hash(),
+                        1 => tx.txid().to_raw_hash(),
-                        2 => tx.wtxid().as_hash(),
+                        2 => tx.wtxid().to_raw_hash(),
                         _ => unreachable!(),
                     },
                     siphash_keys,

bitcoin/src/bip158.rs

@@ -170,7 +170,7 @@ pub struct BlockFilterWriter<'a, W> {
 impl<'a, W: io::Write> BlockFilterWriter<'a, W> {
     /// Creates a new [`BlockFilterWriter`] from `block`.
     pub fn new(writer: &'a mut W, block: &'a Block) -> BlockFilterWriter<'a, W> {
-        let block_hash_as_int = block.block_hash().into_inner();
+        let block_hash_as_int = block.block_hash().to_byte_array();
         let k0 = u64::from_le_bytes(block_hash_as_int[0..8].try_into().expect("8 byte slice"));
         let k1 = u64::from_le_bytes(block_hash_as_int[8..16].try_into().expect("8 byte slice"));
         let writer = GcsFilterWriter::new(writer, k0, k1, M, P);
@@ -225,7 +225,7 @@ pub struct BlockFilterReader {
 impl BlockFilterReader {
     /// Creates a new [`BlockFilterReader`] from `block_hash`.
     pub fn new(block_hash: &BlockHash) -> BlockFilterReader {
-        let block_hash_as_int = block_hash.into_inner();
+        let block_hash_as_int = block_hash.to_byte_array();
         let k0 = u64::from_le_bytes(block_hash_as_int[0..8].try_into().expect("8 byte slice"));
         let k1 = u64::from_le_bytes(block_hash_as_int[8..16].try_into().expect("8 byte slice"));
         BlockFilterReader { reader: GcsFilterReader::new(k0, k1, M, P) }

bitcoin/src/blockdata/block.rs

@@ -257,7 +257,7 @@ impl Block {
 
     /// Computes the transaction merkle root.
     pub fn compute_merkle_root(&self) -> Option<TxMerkleNode> {
-        let hashes = self.txdata.iter().map(|obj| obj.txid().as_hash());
+        let hashes = self.txdata.iter().map(|obj| obj.txid().to_raw_hash());
         merkle_tree::calculate_root(hashes).map(|h| h.into())
     }
 
@@ -274,9 +274,9 @@ impl Block {
         let hashes = self.txdata.iter().enumerate().map(|(i, t)| {
             if i == 0 {
                 // Replace the first hash with zeroes.
-                Wtxid::all_zeros().as_hash()
+                Wtxid::all_zeros().to_raw_hash()
             } else {
-                t.wtxid().as_hash()
+                t.wtxid().to_raw_hash()
             }
         });
         merkle_tree::calculate_root(hashes).map(|h| h.into())

bitcoin/src/blockdata/constants.rs

@@ -260,7 +260,7 @@ mod test {
         // The genesis block hash is a double-sha256 and it is displayed backwards.
         let genesis_hash = genesis_block(network).block_hash();
         // We abuse the sha256 hash here so we get a LowerHex impl that does not print the hex backwards.
-        let hash = sha256::Hash::from_slice(&genesis_hash.into_inner()).unwrap();
+        let hash = sha256::Hash::from_slice(genesis_hash.as_byte_array()).unwrap();
         let want = format!("{:02x}", hash);
 
         let chain_hash = ChainHash::using_genesis_block(network);

bitcoin/src/consensus/encode.rs

@@ -762,37 +762,37 @@ tuple_encode!(T0, T1, T2, T3, T4, T5, T6, T7);
 
 impl Encodable for sha256d::Hash {
     fn consensus_encode<W: io::Write + ?Sized>(&self, w: &mut W) -> Result<usize, io::Error> {
-        self.into_inner().consensus_encode(w)
+        self.as_byte_array().consensus_encode(w)
     }
 }
 
 impl Decodable for sha256d::Hash {
     fn consensus_decode<R: io::Read + ?Sized>(r: &mut R) -> Result<Self, Error> {
-        Ok(Self::from_inner(<<Self as Hash>::Inner>::consensus_decode(r)?))
+        Ok(Self::from_byte_array(<<Self as Hash>::Bytes>::consensus_decode(r)?))
     }
 }
 
 impl Encodable for sha256::Hash {
     fn consensus_encode<W: io::Write + ?Sized>(&self, w: &mut W) -> Result<usize, io::Error> {
-        self.into_inner().consensus_encode(w)
+        self.as_byte_array().consensus_encode(w)
     }
 }
 
 impl Decodable for sha256::Hash {
     fn consensus_decode<R: io::Read + ?Sized>(r: &mut R) -> Result<Self, Error> {
-        Ok(Self::from_inner(<<Self as Hash>::Inner>::consensus_decode(r)?))
+        Ok(Self::from_byte_array(<<Self as Hash>::Bytes>::consensus_decode(r)?))
     }
 }
 
 impl Encodable for TapLeafHash {
     fn consensus_encode<W: io::Write + ?Sized>(&self, w: &mut W) -> Result<usize, io::Error> {
-        self.into_inner().consensus_encode(w)
+        self.as_byte_array().consensus_encode(w)
     }
 }
 
 impl Decodable for TapLeafHash {
     fn consensus_decode<R: io::Read + ?Sized>(r: &mut R) -> Result<Self, Error> {
-        Ok(Self::from_inner(<<Self as Hash>::Inner>::consensus_decode(r)?))
+        Ok(Self::from_byte_array(<<Self as Hash>::Bytes>::consensus_decode(r)?))
     }
 }
 

bitcoin/src/crypto/key.rs

@@ -129,8 +129,8 @@ impl PublicKey {
     /// Returns bitcoin 160-bit hash of the public key for witness program
     pub fn wpubkey_hash(&self) -> Option<WPubkeyHash> {
         if self.compressed {
-            Some(WPubkeyHash::from_inner(
+            Some(WPubkeyHash::from_byte_array(
-                hash160::Hash::hash(&self.inner.serialize()).into_inner()
+                hash160::Hash::hash(&self.inner.serialize()).to_byte_array()
             ))
         } else {
             // We can't create witness pubkey hashes for an uncompressed

bitcoin/src/crypto/sighash.rs

@@ -42,7 +42,7 @@ pub(crate) const MIDSTATE_TAPSIGHASH: [u8; 32] = [
 macro_rules! impl_thirty_two_byte_hash {
     ($ty:ident) => {
         impl secp256k1::ThirtyTwoByteHash for $ty {
-            fn into_32(self) -> [u8; 32] { self.into_inner() }
+            fn into_32(self) -> [u8; 32] { self.to_byte_array() }
         }
     }
 }
@@ -679,7 +679,7 @@ impl<R: Borrow<Transaction>> SighashCache<R> {
         //         ss += bytes([0])
         //         ss += struct.pack("<i", codeseparator_pos)
         if let Some((hash, code_separator_pos)) = leaf_hash_code_separator {
-            hash.into_inner().consensus_encode(&mut writer)?;
+            hash.as_byte_array().consensus_encode(&mut writer)?;
             KEY_VERSION_0.consensus_encode(&mut writer)?;
             code_separator_pos.consensus_encode(&mut writer)?;
         }
@@ -991,7 +991,7 @@ impl<R: Borrow<Transaction>> SighashCache<R> {
             .legacy_encode_signing_data_to(&mut enc, input_index, script_pubkey, sighash_type)
             .is_sighash_single_bug()?
         {
-            Ok(LegacySighash::from_inner(UINT256_ONE))
+            Ok(LegacySighash::from_byte_array(UINT256_ONE))
         } else {
             Ok(LegacySighash::from_engine(enc))
         }
@@ -1202,7 +1202,7 @@ mod tests {
         let mut enc = TapSighash::engine();
         enc.input(&bytes);
         let hash = TapSighash::from_engine(enc);
-        assert_eq!(expected, hash.into_inner());
+        assert_eq!(expected, hash.to_byte_array());
     }
 
     #[test]
@@ -1436,7 +1436,7 @@ mod tests {
             .taproot_signature_hash(input_index, &prevouts, annex, leaf_hash, sighash_type)
             .unwrap();
         let expected = Vec::from_hex(expected_hash).unwrap();
-        assert_eq!(expected, hash.into_inner());
+        assert_eq!(expected, hash.to_byte_array());
     }
 
     #[cfg(feature = "serde")]
@@ -1696,15 +1696,15 @@ mod tests {
         let cache = cache.segwit_cache();
         // Parse hex into Vec because BIP143 test vector displays forwards but our sha256d::Hash displays backwards.
         assert_eq!(
-            cache.prevouts.into_inner(),
+            cache.prevouts.as_byte_array(),
             &Vec::from_hex("96b827c8483d4e9b96712b6713a7b68d6e8003a781feba36c31143470b4efd37").unwrap()[..],
         );
         assert_eq!(
-            cache.sequences.into_inner(),
+            cache.sequences.as_byte_array(),
             &Vec::from_hex("52b0a642eea2fb7ae638c36f6252b6750293dbe574a806984b8e4d8548339a3b").unwrap()[..],
         );
         assert_eq!(
-            cache.outputs.into_inner(),
+            cache.outputs.as_byte_array(),
             &Vec::from_hex("863ef3e1a92afbfdb97f31ad0fc7683ee943e9abcf2501590ff8f6551f47e5e5").unwrap()[..],
         );
     }
@@ -1732,15 +1732,15 @@ mod tests {
         let cache = cache.segwit_cache();
         // Parse hex into Vec because BIP143 test vector displays forwards but our sha256d::Hash displays backwards.
         assert_eq!(
-            cache.prevouts.into_inner(),
+            cache.prevouts.as_byte_array(),
             &Vec::from_hex("b0287b4a252ac05af83d2dcef00ba313af78a3e9c329afa216eb3aa2a7b4613a").unwrap()[..],
         );
         assert_eq!(
-            cache.sequences.into_inner(),
+            cache.sequences.as_byte_array(),
             &Vec::from_hex("18606b350cd8bf565266bc352f0caddcf01e8fa789dd8a15386327cf8cabe198").unwrap()[..],
         );
         assert_eq!(
-            cache.outputs.into_inner(),
+            cache.outputs.as_byte_array(),
             &Vec::from_hex("de984f44532e2173ca0d64314fcefe6d30da6f8cf27bafa706da61df8a226c83").unwrap()[..],
         );
     }
@@ -1773,15 +1773,15 @@ mod tests {
         let cache = cache.segwit_cache();
         // Parse hex into Vec because BIP143 test vector displays forwards but our sha256d::Hash displays backwards.
         assert_eq!(
-            cache.prevouts.into_inner(),
+            cache.prevouts.as_byte_array(),
             &Vec::from_hex("74afdc312af5183c4198a40ca3c1a275b485496dd3929bca388c4b5e31f7aaa0").unwrap()[..],
         );
         assert_eq!(
-            cache.sequences.into_inner(),
+            cache.sequences.as_byte_array(),
             &Vec::from_hex("3bb13029ce7b1f559ef5e747fcac439f1455a2ec7c5f09b72290795e70665044").unwrap()[..],
         );
         assert_eq!(
-            cache.outputs.into_inner(),
+            cache.outputs.as_byte_array(),
             &Vec::from_hex("bc4d309071414bed932f98832b27b4d76dad7e6c1346f487a8fdbb8eb90307cc").unwrap()[..],
         );
     }

bitcoin/src/hash_types.rs

@@ -21,7 +21,7 @@ macro_rules! impl_hashencode {
         impl $crate::consensus::Decodable for $hashtype {
             fn consensus_decode<R: $crate::io::Read + ?Sized>(r: &mut R) -> Result<Self, $crate::consensus::encode::Error> {
                 use $crate::hashes::Hash;
-                Ok(Self::from_inner(<<$hashtype as $crate::hashes::Hash>::Inner>::consensus_decode(r)?))
+                Ok(Self::from_byte_array(<<$hashtype as $crate::hashes::Hash>::Bytes>::consensus_decode(r)?))
             }
         }
     };
@@ -34,14 +34,14 @@ macro_rules! impl_asref_push_bytes {
             impl AsRef<$crate::blockdata::script::PushBytes> for $hashtype {
                 fn as_ref(&self) -> &$crate::blockdata::script::PushBytes {
                     use $crate::hashes::Hash;
-                    self.as_inner().as_ref()
+                    self.as_byte_array().into()
                 }
             }
 
             impl From<$hashtype> for $crate::blockdata::script::PushBytesBuf {
                 fn from(hash: $hashtype) -> Self {
                     use $crate::hashes::Hash;
-                    hash.as_inner().into()
+                    hash.as_byte_array().into()
                 }
             }
         )*

bitcoin/src/merkle_tree/block.rs

@@ -305,7 +305,7 @@ impl PartialMerkleTree {
         if hash_used != self.hashes.len() as u32 {
             return Err(NotAllHashesConsumed);
         }
-        Ok(TxMerkleNode::from_inner(hash_merkle_root.into_inner()))
+        Ok(TxMerkleNode::from_byte_array(hash_merkle_root.to_byte_array()))
     }
 
     /// Helper function to efficiently calculate the number of nodes at given height
@@ -319,7 +319,7 @@ impl PartialMerkleTree {
     fn calc_hash(&self, height: u32, pos: u32, txids: &[Txid]) -> TxMerkleNode {
         if height == 0 {
             // Hash at height 0 is the txid itself
-            TxMerkleNode::from_inner(txids[pos as usize].into_inner())
+            TxMerkleNode::from_byte_array(txids[pos as usize].to_byte_array())
         } else {
             // Calculate left hash
             let left = self.calc_hash(height - 1, pos * 2, txids);
@@ -384,7 +384,7 @@ impl PartialMerkleTree {
             *hash_used += 1;
             if height == 0 && parent_of_match {
                 // in case of height 0, we have a matched txid
-                matches.push(Txid::from_inner(hash.into_inner()));
+                matches.push(Txid::from_byte_array(hash.to_byte_array()));
                 indexes.push(pos);
             }
             Ok(hash)
@@ -573,7 +573,7 @@ mod tests {
             .collect::<Vec<_>>();
 
         // Calculate the merkle root and height
-        let hashes = tx_ids.iter().map(|t| t.as_hash());
+        let hashes = tx_ids.iter().map(|t| t.to_raw_hash());
         let merkle_root_1: TxMerkleNode =
             merkle_tree::calculate_root(hashes).expect("hashes is not empty").into();
         let mut height = 1;
@@ -741,7 +741,7 @@ mod tests {
             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();
+            let mut hash = hashes[n].to_byte_array();
             hash[(bit >> 3) as usize] ^= 1 << (bit & 7);
             hashes[n] = TxMerkleNode::from_slice(&hash).unwrap();
         }

bitcoin/src/merkle_tree/mod.rs

@@ -122,7 +122,7 @@ mod tests {
         let block: Block = deserialize(&segwit_block[..]).expect("Failed to deserialize block");
         assert!(block.check_merkle_root()); // Sanity check.
 
-        let hashes_iter = block.txdata.iter().map(|obj| obj.txid().as_hash());
+        let hashes_iter = block.txdata.iter().map(|obj| obj.txid().to_raw_hash());
 
         let mut hashes_array: [sha256d::Hash; 15] = [Hash::all_zeros(); 15];
         for (i, hash) in hashes_iter.clone().enumerate() {

bitcoin/src/network/message.rs

@@ -582,7 +582,7 @@ mod test {
                 flags: BloomFlags::All,
             }),
             NetworkMessage::FilterAdd(FilterAdd { data: script.as_bytes().to_vec() }),
-            NetworkMessage::FilterAdd(FilterAdd { data: hash([29u8; 32]).into_inner().to_vec() }),
+            NetworkMessage::FilterAdd(FilterAdd { data: hash([29u8; 32]).as_byte_array().to_vec() }),
             NetworkMessage::FilterClear,
             NetworkMessage::GetCFilters(GetCFilters {
                 filter_type: 2,

bitcoin/src/pow.rs

@@ -196,7 +196,7 @@ impl Target {
     #[cfg_attr(all(test, mutate), mutate)]
     pub fn is_met_by(&self, hash: BlockHash) -> bool {
         use crate::hashes::Hash;
-        let hash = U256::from_le_bytes(hash.into_inner());
+        let hash = U256::from_le_bytes(hash.to_byte_array());
         hash <= self.0
     }
 
@@ -1492,7 +1492,7 @@ mod tests {
         use crate::hashes::Hash;
 
         let hash = BlockHash::from_str("ef537f25c895bfa782526529a9b63d97aa631564d5d789c2b765448c8635fb6c").expect("failed to parse block hash");
-        let target = Target(U256::from_le_bytes(hash.into_inner()));
+        let target = Target(U256::from_le_bytes(hash.to_byte_array()));
         assert!(target.is_met_by(hash));
     }
 

bitcoin/src/psbt/macros.rs

@@ -169,7 +169,7 @@ macro_rules! impl_psbt_hash_serialize {
     ($hash_type:ty) => {
         impl $crate::psbt::serialize::Serialize for $hash_type {
             fn serialize(&self) -> $crate::prelude::Vec<u8> {
-                self.into_inner().to_vec()
+                self.as_byte_array().to_vec()
             }
         }
     };

bitcoin/src/psbt/serialize.rs

@@ -309,9 +309,9 @@ impl Deserialize for taproot::Signature {
 impl Serialize for (XOnlyPublicKey, TapLeafHash) {
     fn serialize(&self) -> Vec<u8> {
         let ser_pk = self.0.serialize();
-        let mut buf = Vec::with_capacity(ser_pk.len() + self.1.as_inner().len());
+        let mut buf = Vec::with_capacity(ser_pk.len() + self.1.as_byte_array().len());
         buf.extend(&ser_pk);
-        buf.extend(self.1.as_inner());
+        buf.extend(self.1.as_byte_array());
         buf
     }
 }

bitcoin/src/taproot.rs

@@ -79,7 +79,7 @@ impl TapTweakHash {
     /// 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")
+        Scalar::from_be_bytes(self.to_byte_array()).expect("hash value greater than curve order")
     }
 }
 
@@ -122,7 +122,7 @@ impl TapNodeHash {
 }
 
 impl From<TapLeafHash> for TapNodeHash {
-    fn from(leaf: TapLeafHash) -> TapNodeHash { TapNodeHash::from_inner(leaf.into_inner()) }
+    fn from(leaf: TapLeafHash) -> TapNodeHash { TapNodeHash::from_byte_array(leaf.to_byte_array()) }
 }
 
 /// Maximum depth of a taproot tree script spend path.
@@ -690,7 +690,7 @@ impl TaprootMerkleBranch {
 
     /// Serializes `self` as bytes.
     pub fn serialize(&self) -> Vec<u8> {
-        self.0.iter().flat_map(|e| e.as_inner()).copied().collect::<Vec<u8>>()
+        self.0.iter().flat_map(|e| e.as_byte_array()).copied().collect::<Vec<u8>>()
     }
 
     /// Appends elements to proof.
@@ -1152,10 +1152,10 @@ mod test {
         use crate::crypto::sighash::MIDSTATE_TAPSIGHASH;
 
         // check midstate against hard-coded values
-        assert_eq!(MIDSTATE_TAPLEAF, tag_engine("TapLeaf").midstate().into_inner());
+        assert_eq!(MIDSTATE_TAPLEAF, tag_engine("TapLeaf").midstate().to_byte_array());
-        assert_eq!(MIDSTATE_TAPBRANCH, tag_engine("TapBranch").midstate().into_inner());
+        assert_eq!(MIDSTATE_TAPBRANCH, tag_engine("TapBranch").midstate().to_byte_array());
-        assert_eq!(MIDSTATE_TAPTWEAK, tag_engine("TapTweak").midstate().into_inner());
+        assert_eq!(MIDSTATE_TAPTWEAK, tag_engine("TapTweak").midstate().to_byte_array());
-        assert_eq!(MIDSTATE_TAPSIGHASH, tag_engine("TapSighash").midstate().into_inner());
+        assert_eq!(MIDSTATE_TAPSIGHASH, tag_engine("TapSighash").midstate().to_byte_array());
 
         // test that engine creation roundtrips
         assert_eq!(tag_engine("TapLeaf").midstate(), TapLeafTag::engine().midstate());
@@ -1167,12 +1167,12 @@ mod test {
         fn empty_hash(tag_name: &str) -> [u8; 32] {
             let mut e = tag_engine(tag_name);
             e.input(&[]);
-            TapNodeHash::from_engine(e).into_inner()
+            TapNodeHash::from_engine(e).to_byte_array()
         }
-        assert_eq!(empty_hash("TapLeaf"), TapLeafHash::hash(&[]).into_inner());
+        assert_eq!(empty_hash("TapLeaf"), TapLeafHash::hash(&[]).to_byte_array());
-        assert_eq!(empty_hash("TapBranch"), TapNodeHash::hash(&[]).into_inner());
+        assert_eq!(empty_hash("TapBranch"), TapNodeHash::hash(&[]).to_byte_array());
-        assert_eq!(empty_hash("TapTweak"), TapTweakHash::hash(&[]).into_inner());
+        assert_eq!(empty_hash("TapTweak"), TapTweakHash::hash(&[]).to_byte_array());
-        assert_eq!(empty_hash("TapSighash"), TapSighash::hash(&[]).into_inner());
+        assert_eq!(empty_hash("TapSighash"), TapSighash::hash(&[]).to_byte_array());
     }
 
     #[test]

hashes/extended_tests/schemars/src/main.rs

@@ -125,7 +125,7 @@ mod tests {
         impl sha256t::Tag for TestHashTag {
             fn engine() -> sha256::HashEngine {
                 // The TapRoot TapLeaf midstate.
-                let midstate = sha256::Midstate::from_inner(TEST_MIDSTATE);
+                let midstate = sha256::Midstate::from_byte_array(TEST_MIDSTATE);
                 sha256::HashEngine::from_midstate(midstate, 64)
             }
         }

hashes/src/hash160.rs

@@ -97,7 +97,7 @@ mod tests {
             }
             let manual_hash = Hash::from_engine(engine);
             assert_eq!(hash, manual_hash);
-            assert_eq!(hash.into_inner()[..].as_ref(), test.output.as_slice());
+            assert_eq!(hash.to_byte_array()[..].as_ref(), test.output.as_slice());
         }
     }
 

hashes/src/hmac.rs

@@ -192,7 +192,7 @@ impl<T: Hash> borrow::Borrow<[u8]> for Hmac<T> {
 
 impl<T: Hash> Hash for Hmac<T> {
     type Engine = HmacEngine<T>;
-    type Inner = T::Inner;
+    type Bytes = T::Bytes;
 
     fn from_engine(mut e: HmacEngine<T>) -> Hmac<T> {
         let ihash = T::from_engine(e.iengine);
@@ -207,16 +207,16 @@ impl<T: Hash> Hash for Hmac<T> {
         T::from_slice(sl).map(Hmac)
     }
 
-    fn into_inner(self) -> Self::Inner {
+    fn to_byte_array(self) -> Self::Bytes {
-        self.0.into_inner()
+        self.0.to_byte_array()
     }
 
-    fn as_inner(&self) -> &Self::Inner {
+    fn as_byte_array(&self) -> &Self::Bytes {
-        self.0.as_inner()
+        self.0.as_byte_array()
     }
 
-    fn from_inner(inner: T::Inner) -> Self {
+    fn from_byte_array(bytes: T::Bytes) -> Self {
-        Hmac(T::from_inner(inner))
+        Hmac(T::from_byte_array(bytes))
     }
 
     fn all_zeros() -> Self {
@@ -237,8 +237,8 @@ impl<T: Hash + Serialize> Serialize for Hmac<T> {
 #[cfg_attr(docsrs, doc(cfg(feature = "serde")))]
 impl<'de, T: Hash + Deserialize<'de>> Deserialize<'de> for Hmac<T> {
     fn deserialize<D: Deserializer<'de>>(d: D) -> Result<Hmac<T>, D::Error> {
-        let inner = Deserialize::deserialize(d)?;
+        let bytes = Deserialize::deserialize(d)?;
-        Ok(Hmac(inner))
+        Ok(Hmac(bytes))
     }
 }
 
@@ -365,7 +365,7 @@ mod tests {
             engine.input(&test.input);
             let hash = Hmac::<sha256::Hash>::from_engine(engine);
             assert_eq!(&hash[..], &test.output[..]);
-            assert_eq!(hash.into_inner()[..].as_ref(), test.output.as_slice());
+            assert_eq!(hash.as_byte_array(), test.output.as_slice());
         }
     }
 

hashes/src/internal_macros.rs

@@ -97,7 +97,7 @@ macro_rules! hash_trait_impls {
                 } else {
                     FromHex::from_byte_iter(HexIterator::new(s)?)?
                 };
-                Ok(Self::from_inner(inner))
+                Ok(Self::from_byte_array(inner))
             }
         }
 
@@ -122,7 +122,7 @@ macro_rules! hash_trait_impls {
 
         impl<$($gen: $gent),*> crate::Hash for Hash<$($gen),*> {
             type Engine = HashEngine;
-            type Inner = [u8; $bits / 8];
+            type Bytes = [u8; $bits / 8];
 
             const LEN: usize = $bits / 8;
             const DISPLAY_BACKWARD: bool = $reverse;
@@ -145,16 +145,16 @@ macro_rules! hash_trait_impls {
                 }
             }
 
-            fn into_inner(self) -> Self::Inner {
+            fn to_byte_array(self) -> Self::Bytes {
                 self.0
             }
 
-            fn as_inner(&self) -> &Self::Inner {
+            fn as_byte_array(&self) -> &Self::Bytes {
                 &self.0
             }
 
-            fn from_inner(inner: Self::Inner) -> Self {
+            fn from_byte_array(bytes: Self::Bytes) -> Self {
-                Self::internal_new(inner)
+                Self::internal_new(bytes)
             }
 
             fn all_zeros() -> Self {

hashes/src/lib.rs

@@ -171,7 +171,7 @@ pub trait Hash: Copy + Clone + PartialEq + Eq + PartialOrd + Ord +
     type Engine: HashEngine;
 
     /// The byte array that represents the hash internally.
-    type Inner: hex::FromHex;
+    type Bytes: hex::FromHex + Copy;
 
     /// Constructs a new engine.
     fn engine() -> Self::Engine {
@@ -199,14 +199,14 @@ pub trait Hash: Copy + Clone + PartialEq + Eq + PartialOrd + Ord +
     /// true for `Sha256dHash`, so here we are.
     const DISPLAY_BACKWARD: bool = false;
 
-    /// Unwraps the hash and returns the underlying byte array.
+    /// Returns the underlying byte array.
-    fn into_inner(self) -> Self::Inner;
+    fn to_byte_array(self) -> Self::Bytes;
 
-    /// Unwraps the hash and returns a reference to the underlying byte array.
+    /// Returns a reference to the underlying byte array.
-    fn as_inner(&self) -> &Self::Inner;
+    fn as_byte_array(&self) -> &Self::Bytes;
 
     /// Constructs a hash from the underlying byte array.
-    fn from_inner(inner: Self::Inner) -> Self;
+    fn from_byte_array(bytes: Self::Bytes) -> Self;
 
     /// Returns an all zero hash.
     ///
@@ -231,11 +231,11 @@ mod tests {
     #[test]
     fn convert_newtypes() {
         let h1 = TestNewtype::hash(&[]);
-        let h2: TestNewtype2 = h1.as_hash().into();
+        let h2: TestNewtype2 = h1.to_raw_hash().into();
         assert_eq!(&h1[..], &h2[..]);
 
         let h = sha256d::Hash::hash(&[]);
         let h2: TestNewtype = h.to_string().parse().unwrap();
-        assert_eq!(h2.as_hash(), h);
+        assert_eq!(h2.to_raw_hash(), h);
     }
 }

hashes/src/ripemd160.rs

@@ -480,7 +480,7 @@ mod tests {
             }
             let manual_hash = ripemd160::Hash::from_engine(engine);
             assert_eq!(hash, manual_hash);
-            assert_eq!(hash.into_inner()[..].as_ref(), test.output.as_slice());
+            assert_eq!(hash.as_byte_array(), test.output.as_slice());
         }
     }
 

hashes/src/sha1.rs

@@ -206,7 +206,7 @@ mod tests {
             }
             let manual_hash = sha1::Hash::from_engine(engine);
             assert_eq!(hash, manual_hash);
-            assert_eq!(hash.into_inner()[..].as_ref(), test.output.as_slice());
+            assert_eq!(hash.as_byte_array(), test.output.as_slice());
         }
     }
 

hashes/src/sha256.rs

@@ -46,12 +46,12 @@ fn from_engine(mut e: HashEngine) -> Hash {
     e.input(&(8 * data_len).to_be_bytes());
     debug_assert_eq!(e.length % BLOCK_SIZE, 0);
 
-    Hash(e.midstate().into_inner())
+    Hash(e.midstate().to_byte_array())
 }
 
 #[cfg(fuzzing)]
 fn from_engine(e: HashEngine) -> Hash {
-    let mut hash = e.midstate().into_inner();
+    let mut hash = e.midstate().to_byte_array();
     if hash == [0; 32] {
         // Assume sha256 is secure and never generate 0-hashes (which represent invalid
         // secp256k1 secret keys, causing downstream application breakage).
@@ -111,7 +111,7 @@ impl crate::HashEngine for HashEngine {
 impl Hash {
     /// Iterate the sha256 algorithm to turn a sha256 hash into a sha256d hash
     pub fn hash_again(&self) -> sha256d::Hash {
-        crate::Hash::from_inner(<Self as crate::Hash>::hash(&self.0).0)
+        crate::Hash::from_byte_array(<Self as crate::Hash>::hash(&self.0).0)
     }
 }
 
@@ -149,7 +149,7 @@ impl Midstate {
     const DISPLAY_BACKWARD: bool = true;
 
     /// Construct a new [`Midstate`] from the inner value.
-    pub fn from_inner(inner: [u8; 32]) -> Self {
+    pub fn from_byte_array(inner: [u8; 32]) -> Self {
         Midstate(inner)
     }
 
@@ -165,7 +165,7 @@ impl Midstate {
     }
 
     /// Unwraps the [`Midstate`] and returns the underlying byte array.
-    pub fn into_inner(self) -> [u8; 32] {
+    pub fn to_byte_array(self) -> [u8; 32] {
         self.0
     }
 }
@@ -176,7 +176,7 @@ impl hex::FromHex for Midstate {
         I: Iterator<Item = Result<u8, hex::Error>> + ExactSizeIterator + DoubleEndedIterator,
     {
         // DISPLAY_BACKWARD is true
-        Ok(Midstate::from_inner(hex::FromHex::from_byte_iter(iter.rev())?))
+        Ok(Midstate::from_byte_array(hex::FromHex::from_byte_iter(iter.rev())?))
     }
 }
 
@@ -381,7 +381,7 @@ mod tests {
             }
             let manual_hash = sha256::Hash::from_engine(engine);
             assert_eq!(hash, manual_hash);
-            assert_eq!(hash.into_inner()[..].as_ref(), test.output.as_slice());
+            assert_eq!(hash.to_byte_array()[..].as_ref(), test.output.as_slice());
         }
     }
 
@@ -402,7 +402,7 @@ mod tests {
         assert_eq!(
             engine.midstate(),
             // RPC output
-            sha256::Midstate::from_inner([
+            sha256::Midstate::from_byte_array([
                 0x0b, 0xcf, 0xe0, 0xe5, 0x4e, 0x6c, 0xc7, 0xd3,
                 0x4f, 0x4f, 0x7c, 0x1d, 0xf0, 0xb0, 0xf5, 0x03,
                 0xf2, 0xf7, 0x12, 0x91, 0x2a, 0x06, 0x05, 0xb4,
@@ -455,7 +455,7 @@ mod tests {
             0xd5, 0x69, 0x09, 0x59,
         ];
         let midstate_engine =
-            sha256::HashEngine::from_midstate(sha256::Midstate::from_inner(MIDSTATE), 64);
+            sha256::HashEngine::from_midstate(sha256::Midstate::from_byte_array(MIDSTATE), 64);
         let hash = sha256::Hash::from_engine(midstate_engine);
         assert_eq!(hash, sha256::Hash(HASH_EXPECTED));
     }

hashes/src/sha256d.rs

@@ -89,7 +89,7 @@ mod tests {
             let sha2d_hash = sha2_hash.hash_again();
             assert_eq!(hash, sha2d_hash);
 
-            assert_eq!(hash.into_inner()[..].as_ref(), test.output.as_slice());
+            assert_eq!(hash.to_byte_array()[..].as_ref(), test.output.as_slice());
         }
     }
 

hashes/src/sha256t.rs

@@ -88,7 +88,7 @@ crate::internal_macros::hash_trait_impls!(256, true, T: Tag);
 fn from_engine<T: Tag>(e: sha256::HashEngine) -> Hash<T> {
     use crate::Hash as _;
 
-    Hash::from_inner(sha256::Hash::from_engine(e).into_inner())
+    Hash::from_byte_array(sha256::Hash::from_engine(e).to_byte_array())
 }
 
 /// Macro used to define a newtype tagged hash.
@@ -110,7 +110,7 @@ macro_rules! sha256t_hash_newtype {
 
         impl $crate::sha256t::Tag for $tag {
             fn engine() -> $crate::sha256::HashEngine {
-                let midstate = $crate::sha256::Midstate::from_inner($midstate);
+                let midstate = $crate::sha256::Midstate::from_byte_array($midstate);
                 $crate::sha256::HashEngine::from_midstate(midstate, $midstate_len)
             }
         }
@@ -141,7 +141,7 @@ mod tests {
     impl sha256t::Tag for TestHashTag {
         fn engine() -> sha256::HashEngine {
             // The TapRoot TapLeaf midstate.
-            let midstate = sha256::Midstate::from_inner(TEST_MIDSTATE);
+            let midstate = sha256::Midstate::from_byte_array(TEST_MIDSTATE);
             sha256::HashEngine::from_midstate(midstate, 64)
         }
     }

hashes/src/sha512.rs

@@ -379,7 +379,7 @@ mod tests {
             }
             let manual_hash = sha512::Hash::from_engine(engine);
             assert_eq!(hash, manual_hash);
-            assert_eq!(hash.into_inner()[..].as_ref(), test.output.as_slice());
+            assert_eq!(hash.to_byte_array()[..].as_ref(), test.output.as_slice());
         }
     }
 

hashes/src/sha512_256.rs

@@ -165,7 +165,7 @@ mod tests {
             }
             let manual_hash = sha512_256::Hash::from_engine(engine);
             assert_eq!(hash, manual_hash);
-            assert_eq!(hash.into_inner()[..].as_ref(), test.output.as_slice());
+            assert_eq!(hash.to_byte_array()[..].as_ref(), test.output.as_slice());
         }
     }
 }

hashes/src/util.rs

@@ -173,18 +173,23 @@ macro_rules! hash_newtype {
         $crate::borrow_slice_impl!($newtype);
 
         impl $newtype {
-            /// Creates this type from the inner hash type.
+            /// Creates this wrapper type from the inner hash type.
             #[allow(unused)] // the user of macro may not need this
-            pub fn from_hash(inner: $hash) -> $newtype {
+            pub fn from_raw_hash(inner: $hash) -> $newtype {
                 $newtype(inner)
             }
 
-            /// Converts this type into the inner hash type.
+            /// Returns the inner hash (sha256, sh256d etc.).
             #[allow(unused)] // the user of macro may not need this
-            pub fn as_hash(&self) -> $hash {
+            pub fn to_raw_hash(self) -> $hash {
-                // Hashes implement Copy so don't need into_hash.
                 self.0
             }
+
+            /// Returns a reference to the inner hash (sha256, sh256d etc.).
+            #[allow(unused)] // the user of macro may not need this
+            pub fn as_raw_hash(&self) -> &$hash {
+                &self.0
+            }
         }
 
         impl $crate::_export::_core::convert::From<$hash> for $newtype {
@@ -202,7 +207,7 @@ macro_rules! hash_newtype {
 
         impl $crate::Hash for $newtype {
             type Engine = <$hash as $crate::Hash>::Engine;
-            type Inner = <$hash as $crate::Hash>::Inner;
+            type Bytes = <$hash as $crate::Hash>::Bytes;
 
             const LEN: usize = <$hash as $crate::Hash>::LEN;
             const DISPLAY_BACKWARD: bool = $crate::hash_newtype_get_direction!($hash, $(#[$($type_attrs)*])*);
@@ -221,18 +226,18 @@ macro_rules! hash_newtype {
             }
 
             #[inline]
-            fn from_inner(inner: Self::Inner) -> Self {
+            fn from_byte_array(bytes: Self::Bytes) -> Self {
-                $newtype(<$hash as $crate::Hash>::from_inner(inner))
+                $newtype(<$hash as $crate::Hash>::from_byte_array(bytes))
             }
 
             #[inline]
-            fn into_inner(self) -> Self::Inner {
+            fn to_byte_array(self) -> Self::Bytes {
-                self.0.into_inner()
+                self.0.to_byte_array()
             }
 
             #[inline]
-            fn as_inner(&self) -> &Self::Inner {
+            fn as_byte_array(&self) -> &Self::Bytes {
-                self.0.as_inner()
+                self.0.as_byte_array()
             }
 
             #[inline]
@@ -248,12 +253,12 @@ macro_rules! hash_newtype {
                 use $crate::hex::{HexIterator, FromHex};
                 use $crate::Hash;
 
-                let inner: <$hash as Hash>::Inner = if <Self as $crate::Hash>::DISPLAY_BACKWARD {
+                let inner: <$hash as Hash>::Bytes = if <Self as $crate::Hash>::DISPLAY_BACKWARD {
                     FromHex::from_byte_iter(HexIterator::new(s)?.rev())?
                 } else {
                     FromHex::from_byte_iter(HexIterator::new(s)?)?
                 };
-                Ok($newtype(<$hash>::from_inner(inner)))
+                Ok($newtype(<$hash>::from_byte_array(inner)))
             }
         }
 
@@ -374,14 +379,14 @@ mod test {
     fn hash_as_ref_array() {
         let hash = sha256::Hash::hash(&[3, 50]);
         let r = AsRef::<[u8; 32]>::as_ref(&hash);
-        assert_eq!(r, hash.as_inner());
+        assert_eq!(r, hash.as_byte_array());
     }
 
     #[test]
     fn hash_as_ref_slice() {
         let hash = sha256::Hash::hash(&[3, 50]);
         let r = AsRef::<[u8]>::as_ref(&hash);
-        assert_eq!(r, hash.as_inner());
+        assert_eq!(r, hash.as_byte_array());
     }
 
     #[test]
@@ -390,7 +395,7 @@ mod test {
 
         let hash = sha256::Hash::hash(&[3, 50]);
         let borrowed: &[u8] = hash.borrow();
-        assert_eq!(borrowed, hash.as_inner());
+        assert_eq!(borrowed, hash.as_byte_array());
     }
 
     hash_newtype! {
@@ -430,13 +435,13 @@ mod test {
     fn inner_hash_as_ref_array() {
         let hash = TestHash::all_zeros();
         let r = AsRef::<[u8; 32]>::as_ref(&hash);
-        assert_eq!(r, hash.as_inner());
+        assert_eq!(r, hash.as_byte_array());
     }
 
     #[test]
     fn inner_hash_as_ref_slice() {
         let hash = TestHash::all_zeros();
         let r = AsRef::<[u8]>::as_ref(&hash);
-        assert_eq!(r, hash.as_inner());
+        assert_eq!(r, hash.as_byte_array());
     }
 }