1971 lines
90 KiB
Rust
1971 lines
90 KiB
Rust
// SPDX-License-Identifier: CC0-1.0
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//! Bitcoin Taproot.
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//!
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//! This module provides support for taproot tagged hashes.
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//!
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use core::cmp::Reverse;
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use core::convert::TryFrom;
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use core::fmt;
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use core::iter::FusedIterator;
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use hashes::{sha256t_hash_newtype, Hash, HashEngine};
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use internals::write_err;
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use secp256k1::{self, Scalar, Secp256k1};
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use crate::consensus::Encodable;
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use crate::crypto::key::{TapTweak, TweakedPublicKey, UntweakedPublicKey, XOnlyPublicKey};
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// Re-export these so downstream only has to use one `taproot` module.
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pub use crate::crypto::taproot::{SigFromSliceError, Signature};
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use crate::prelude::*;
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use crate::{io, Script, ScriptBuf};
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// Taproot test vectors from BIP-341 state the hashes without any reversing
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sha256t_hash_newtype! {
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pub struct TapLeafTag = hash_str("TapLeaf");
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/// Taproot-tagged hash with tag \"TapLeaf\".
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///
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/// This is used for computing tapscript script spend hash.
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#[hash_newtype(forward)]
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pub struct TapLeafHash(_);
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pub struct TapBranchTag = hash_str("TapBranch");
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/// Tagged hash used in taproot trees.
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///
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/// See BIP-340 for tagging rules.
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#[hash_newtype(forward)]
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pub struct TapNodeHash(_);
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pub struct TapTweakTag = hash_str("TapTweak");
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/// Taproot-tagged hash with tag \"TapTweak\".
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///
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/// This hash type is used while computing the tweaked public key.
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#[hash_newtype(forward)]
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pub struct TapTweakHash(_);
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}
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impl TapTweakHash {
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/// Creates a new BIP341 [`TapTweakHash`] from key and tweak. Produces `H_taptweak(P||R)` where
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/// `P` is the internal key and `R` is the merkle root.
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pub fn from_key_and_tweak(
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internal_key: UntweakedPublicKey,
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merkle_root: Option<TapNodeHash>,
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) -> TapTweakHash {
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let mut eng = TapTweakHash::engine();
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// always hash the key
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eng.input(&internal_key.serialize());
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if let Some(h) = merkle_root {
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eng.input(h.as_ref());
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} else {
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// nothing to hash
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}
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TapTweakHash::from_engine(eng)
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}
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/// Converts a `TapTweakHash` into a `Scalar` ready for use with key tweaking API.
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pub fn to_scalar(self) -> Scalar {
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// This is statistically extremely unlikely to panic.
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Scalar::from_be_bytes(self.to_byte_array()).expect("hash value greater than curve order")
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}
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}
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impl TapLeafHash {
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/// Computes the leaf hash from components.
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pub fn from_script(script: &Script, ver: LeafVersion) -> TapLeafHash {
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let mut eng = TapLeafHash::engine();
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ver.to_consensus().consensus_encode(&mut eng).expect("engines don't error");
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script.consensus_encode(&mut eng).expect("engines don't error");
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TapLeafHash::from_engine(eng)
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}
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}
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impl From<LeafNode> for TapNodeHash {
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fn from(leaf: LeafNode) -> TapNodeHash { leaf.node_hash() }
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}
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impl From<&LeafNode> for TapNodeHash {
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fn from(leaf: &LeafNode) -> TapNodeHash { leaf.node_hash() }
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}
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impl TapNodeHash {
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/// Computes branch hash given two hashes of the nodes underneath it.
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pub fn from_node_hashes(a: TapNodeHash, b: TapNodeHash) -> TapNodeHash {
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Self::combine_node_hashes(a, b).0
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}
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/// Computes branch hash given two hashes of the nodes underneath it and returns
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/// whether the left node was the one hashed first.
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fn combine_node_hashes(a: TapNodeHash, b: TapNodeHash) -> (TapNodeHash, bool) {
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let mut eng = TapNodeHash::engine();
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if a < b {
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eng.input(a.as_ref());
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eng.input(b.as_ref());
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} else {
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eng.input(b.as_ref());
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eng.input(a.as_ref());
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};
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(TapNodeHash::from_engine(eng), a < b)
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}
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/// Assumes the given 32 byte array as hidden [`TapNodeHash`].
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///
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/// Similar to [`TapLeafHash::from_byte_array`], but explicitly conveys that the
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/// hash is constructed from a hidden node. This also has better ergonomics
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/// because it does not require the caller to import the Hash trait.
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pub fn assume_hidden(hash: [u8; 32]) -> TapNodeHash { TapNodeHash::from_byte_array(hash) }
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/// Computes the [`TapNodeHash`] from a script and a leaf version.
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pub fn from_script(script: &Script, ver: LeafVersion) -> TapNodeHash {
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TapNodeHash::from(TapLeafHash::from_script(script, ver))
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}
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}
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impl From<TapLeafHash> for TapNodeHash {
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fn from(leaf: TapLeafHash) -> TapNodeHash { TapNodeHash::from_byte_array(leaf.to_byte_array()) }
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}
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/// Maximum depth of a taproot tree script spend path.
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// https://github.com/bitcoin/bitcoin/blob/e826b22da252e0599c61d21c98ff89f366b3120f/src/script/interpreter.h#L229
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pub const TAPROOT_CONTROL_MAX_NODE_COUNT: usize = 128;
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/// Size of a taproot control node.
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// https://github.com/bitcoin/bitcoin/blob/e826b22da252e0599c61d21c98ff89f366b3120f/src/script/interpreter.h#L228
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pub const TAPROOT_CONTROL_NODE_SIZE: usize = 32;
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/// Tapleaf mask for getting the leaf version from first byte of control block.
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// https://github.com/bitcoin/bitcoin/blob/e826b22da252e0599c61d21c98ff89f366b3120f/src/script/interpreter.h#L225
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pub const TAPROOT_LEAF_MASK: u8 = 0xfe;
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/// Tapscript leaf version.
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// https://github.com/bitcoin/bitcoin/blob/e826b22da252e0599c61d21c98ff89f366b3120f/src/script/interpreter.h#L226
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pub const TAPROOT_LEAF_TAPSCRIPT: u8 = 0xc0;
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/// Taproot annex prefix.
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pub const TAPROOT_ANNEX_PREFIX: u8 = 0x50;
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/// Tapscript control base size.
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// https://github.com/bitcoin/bitcoin/blob/e826b22da252e0599c61d21c98ff89f366b3120f/src/script/interpreter.h#L227
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pub const TAPROOT_CONTROL_BASE_SIZE: usize = 33;
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/// Tapscript control max size.
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// https://github.com/bitcoin/bitcoin/blob/e826b22da252e0599c61d21c98ff89f366b3120f/src/script/interpreter.h#L230
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pub const TAPROOT_CONTROL_MAX_SIZE: usize =
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TAPROOT_CONTROL_BASE_SIZE + TAPROOT_CONTROL_NODE_SIZE * TAPROOT_CONTROL_MAX_NODE_COUNT;
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// type alias for versioned tap script corresponding merkle proof
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type ScriptMerkleProofMap = BTreeMap<(ScriptBuf, LeafVersion), BTreeSet<TaprootMerkleBranch>>;
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/// Represents taproot spending information.
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///
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/// Taproot output corresponds to a combination of a single public key condition (known as the
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/// internal key), and zero or more general conditions encoded in scripts organized in the form of a
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/// binary tree.
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///
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/// Taproot can be spent by either:
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/// - Spending using the key path i.e., with secret key corresponding to the tweaked `output_key`.
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/// - By satisfying any of the scripts in the script spend path. Each script can be satisfied by
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/// providing a witness stack consisting of the script's inputs, plus the script itself and the
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/// control block.
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///
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/// If one or more of the spending conditions consist of just a single key (after aggregation), the
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/// most likely key should be made the internal key.
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/// See [BIP341](https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki) for more details on
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/// choosing internal keys for a taproot application.
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///
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/// Note: This library currently does not support
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/// [annex](https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki#cite_note-5).
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#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
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pub struct TaprootSpendInfo {
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/// The BIP341 internal key.
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internal_key: UntweakedPublicKey,
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/// The merkle root of the script tree (None if there are no scripts).
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merkle_root: Option<TapNodeHash>,
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/// The sign final output pubkey as per BIP 341.
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output_key_parity: secp256k1::Parity,
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/// The tweaked output key.
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output_key: TweakedPublicKey,
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/// Map from (script, leaf_version) to (sets of) [`TaprootMerkleBranch`]. More than one control
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/// block for a given script is only possible if it appears in multiple branches of the tree. In
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/// all cases, keeping one should be enough for spending funds, but we keep all of the paths so
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/// that a full tree can be constructed again from spending data if required.
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script_map: ScriptMerkleProofMap,
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}
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impl TaprootSpendInfo {
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/// Creates a new [`TaprootSpendInfo`] from a list of scripts (with default script version) and
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/// weights of satisfaction for that script.
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///
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/// See [`TaprootBuilder::with_huffman_tree`] for more detailed documentation.
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pub fn with_huffman_tree<C, I>(
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secp: &Secp256k1<C>,
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internal_key: UntweakedPublicKey,
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script_weights: I,
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) -> Result<Self, TaprootBuilderError>
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where
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I: IntoIterator<Item = (u32, ScriptBuf)>,
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C: secp256k1::Verification,
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{
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let builder = TaprootBuilder::with_huffman_tree(script_weights)?;
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Ok(builder.finalize(secp, internal_key).expect("Huffman Tree is always complete"))
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}
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/// Creates a new key spend with `internal_key` and `merkle_root`. Provide [`None`] for
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/// the `merkle_root` if there is no script path.
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///
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/// *Note*: As per BIP341
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///
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/// When the merkle root is [`None`], the output key commits to an unspendable script path
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/// instead of having no script path. This is achieved by computing the output key point as
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/// `Q = P + int(hashTapTweak(bytes(P)))G`. See also [`TaprootSpendInfo::tap_tweak`].
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///
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/// Refer to BIP 341 footnote ('Why should the output key always have a taproot commitment, even
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/// if there is no script path?') for more details.
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pub fn new_key_spend<C: secp256k1::Verification>(
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secp: &Secp256k1<C>,
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internal_key: UntweakedPublicKey,
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merkle_root: Option<TapNodeHash>,
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) -> Self {
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let (output_key, parity) = internal_key.tap_tweak(secp, merkle_root);
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Self {
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internal_key,
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merkle_root,
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output_key_parity: parity,
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output_key,
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script_map: BTreeMap::new(),
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}
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}
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/// Returns the `TapTweakHash` for this [`TaprootSpendInfo`] i.e., the tweak using `internal_key`
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/// and `merkle_root`.
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pub fn tap_tweak(&self) -> TapTweakHash {
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TapTweakHash::from_key_and_tweak(self.internal_key, self.merkle_root)
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}
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/// Returns the internal key for this [`TaprootSpendInfo`].
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pub fn internal_key(&self) -> UntweakedPublicKey { self.internal_key }
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/// Returns the merkle root for this [`TaprootSpendInfo`].
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pub fn merkle_root(&self) -> Option<TapNodeHash> { self.merkle_root }
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/// Returns the output key (the key used in script pubkey) for this [`TaprootSpendInfo`].
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pub fn output_key(&self) -> TweakedPublicKey { self.output_key }
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/// Returns the parity of the output key. See also [`TaprootSpendInfo::output_key`].
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pub fn output_key_parity(&self) -> secp256k1::Parity { self.output_key_parity }
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/// Returns a reference to the internal script map.
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pub fn script_map(&self) -> &ScriptMerkleProofMap { &self.script_map }
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/// Computes the [`TaprootSpendInfo`] from `internal_key` and `node`.
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///
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/// This is useful when you want to manually build a taproot tree without using
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/// [`TaprootBuilder`].
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pub fn from_node_info<C: secp256k1::Verification>(
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secp: &Secp256k1<C>,
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internal_key: UntweakedPublicKey,
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node: NodeInfo,
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) -> TaprootSpendInfo {
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// Create as if it is a key spend path with the given merkle root
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let root_hash = Some(node.hash);
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let mut info = TaprootSpendInfo::new_key_spend(secp, internal_key, root_hash);
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for leaves in node.leaves {
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match leaves.leaf {
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TapLeaf::Hidden(_) => {
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// We don't store any information about hidden nodes in TaprootSpendInfo.
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}
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TapLeaf::Script(script, ver) => {
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let key = (script, ver);
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let value = leaves.merkle_branch;
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match info.script_map.get_mut(&key) {
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None => {
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let mut set = BTreeSet::new();
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set.insert(value);
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info.script_map.insert(key, set);
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}
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Some(set) => {
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set.insert(value);
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}
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}
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}
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}
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}
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info
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}
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/// Returns the internal script map.
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#[deprecated(since = "0.31.0", note = "use Self::script_map instead")]
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pub fn as_script_map(&self) -> &ScriptMerkleProofMap { self.script_map() }
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/// Constructs a [`ControlBlock`] for particular script with the given version.
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///
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/// # Returns
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///
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/// - If there are multiple control blocks possible, returns the shortest one.
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/// - If the script is not contained in the [`TaprootSpendInfo`], returns `None`.
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pub fn control_block(&self, script_ver: &(ScriptBuf, LeafVersion)) -> Option<ControlBlock> {
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let merkle_branch_set = self.script_map.get(script_ver)?;
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// Choose the smallest one amongst the multiple script maps
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let smallest = merkle_branch_set
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.iter()
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.min_by(|x, y| x.0.len().cmp(&y.0.len()))
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.expect("Invariant: ScriptBuf map key must contain non-empty set value");
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Some(ControlBlock {
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internal_key: self.internal_key,
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output_key_parity: self.output_key_parity,
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leaf_version: script_ver.1,
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merkle_branch: smallest.clone(),
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})
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}
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}
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impl From<TaprootSpendInfo> for TapTweakHash {
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fn from(spend_info: TaprootSpendInfo) -> TapTweakHash { spend_info.tap_tweak() }
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}
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impl From<&TaprootSpendInfo> for TapTweakHash {
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fn from(spend_info: &TaprootSpendInfo) -> TapTweakHash { spend_info.tap_tweak() }
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}
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/// Builder for building taproot iteratively. Users can specify tap leaf or omitted/hidden branches
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/// in a depth-first search (DFS) walk order to construct this tree.
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///
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/// See Wikipedia for more details on [DFS](https://en.wikipedia.org/wiki/Depth-first_search).
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// Similar to Taproot Builder in Bitcoin Core.
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#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
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pub struct TaprootBuilder {
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// The following doc-comment is from Bitcoin Core, but modified for Rust. It describes the
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// current state of the builder for a given tree.
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//
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// For each level in the tree, one NodeInfo object may be present. Branch at index 0 is
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// information about the root; further values are for deeper subtrees being explored.
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//
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// During the construction of Taptree, for every right branch taken to reach the position we're
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// currently working on, there will be a `(Some(_))` entry in branch corresponding to the left
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// branch at that level.
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//
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// For example, imagine this tree: - N0 -
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// / \
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// N1 N2
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// / \ / \
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// A B C N3
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// / \
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// D E
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//
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// Initially, branch is empty. After processing leaf A, it would become {None, None, A}. When
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// processing leaf B, an entry at level 2 already exists, and it would thus be combined with it
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// to produce a level 1 entry, resulting in {None, N1}. Adding C and D takes us to {None, N1, C}
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// and {None, N1, C, D} respectively. When E is processed, it is combined with D, and then C,
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// and then N1, to produce the root, resulting in {N0}.
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//
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// This structure allows processing with just O(log n) overhead if the leaves are computed on
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// the fly.
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//
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// As an invariant, there can never be None entries at the end. There can also not be more than
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// 128 entries (as that would mean more than 128 levels in the tree). The depth of newly added
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// entries will always be at least equal to the current size of branch (otherwise it does not
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// correspond to a depth-first traversal of a tree). A branch is only empty if no entries have
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// ever be processed. A branch having length 1 corresponds to being done.
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branch: Vec<Option<NodeInfo>>,
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}
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impl TaprootBuilder {
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/// Creates a new instance of [`TaprootBuilder`].
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pub fn new() -> Self { TaprootBuilder { branch: vec![] } }
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/// Creates a new instance of [`TaprootBuilder`] with a capacity hint for `size` elements.
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///
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/// The size here should be maximum depth of the tree.
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pub fn with_capacity(size: usize) -> Self {
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TaprootBuilder { branch: Vec::with_capacity(size) }
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}
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/// Creates a new [`TaprootSpendInfo`] from a list of scripts (with default script version) and
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/// weights of satisfaction for that script.
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///
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/// The weights represent the probability of each branch being taken. If probabilities/weights
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/// for each condition are known, constructing the tree as a Huffman Tree is the optimal way to
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/// minimize average case satisfaction cost. This function takes as input an iterator of
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/// `tuple(u32, ScriptBuf)` where `u32` represents the satisfaction weights of the branch. For
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/// example, [(3, S1), (2, S2), (5, S3)] would construct a [`TapTree`] that has optimal
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/// satisfaction weight when probability for S1 is 30%, S2 is 20% and S3 is 50%.
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///
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/// # Errors:
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///
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/// - When the optimal Huffman Tree has a depth more than 128.
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/// - If the provided list of script weights is empty.
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///
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/// # Edge Cases:
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///
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/// If the script weight calculations overflow, a sub-optimal tree may be generated. This should
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/// not happen unless you are dealing with billions of branches with weights close to 2^32.
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///
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/// [`TapTree`]: crate::taproot::TapTree
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pub fn with_huffman_tree<I>(script_weights: I) -> Result<Self, TaprootBuilderError>
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where
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I: IntoIterator<Item = (u32, ScriptBuf)>,
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{
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let mut node_weights = BinaryHeap::<(Reverse<u32>, NodeInfo)>::new();
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for (p, leaf) in script_weights {
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node_weights
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.push((Reverse(p), NodeInfo::new_leaf_with_ver(leaf, LeafVersion::TapScript)));
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}
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if node_weights.is_empty() {
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return Err(TaprootBuilderError::EmptyTree);
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}
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while node_weights.len() > 1 {
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// Combine the last two elements and insert a new node
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let (p1, s1) = node_weights.pop().expect("len must be at least two");
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let (p2, s2) = node_weights.pop().expect("len must be at least two");
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// Insert the sum of first two in the tree as a new node
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// N.B.: p1 + p2 can not practically saturate as you would need to have 2**32 max u32s
|
|
// from the input to overflow. However, saturating is a reasonable behavior here as
|
|
// huffman tree construction would treat all such elements as "very likely".
|
|
let p = Reverse(p1.0.saturating_add(p2.0));
|
|
node_weights.push((p, NodeInfo::combine(s1, s2)?));
|
|
}
|
|
// Every iteration of the loop reduces the node_weights.len() by exactly 1
|
|
// Therefore, the loop will eventually terminate with exactly 1 element
|
|
debug_assert_eq!(node_weights.len(), 1);
|
|
let node = node_weights.pop().expect("huffman tree algorithm is broken").1;
|
|
Ok(TaprootBuilder { branch: vec![Some(node)] })
|
|
}
|
|
|
|
/// Adds a leaf script at `depth` to the builder with script version `ver`. Errors if the leaves
|
|
/// are not provided in DFS walk order. The depth of the root node is 0.
|
|
pub fn add_leaf_with_ver(
|
|
self,
|
|
depth: u8,
|
|
script: ScriptBuf,
|
|
ver: LeafVersion,
|
|
) -> Result<Self, TaprootBuilderError> {
|
|
let leaf = NodeInfo::new_leaf_with_ver(script, ver);
|
|
self.insert(leaf, depth)
|
|
}
|
|
|
|
/// Adds a leaf script at `depth` to the builder with default script version. Errors if the
|
|
/// leaves are not provided in DFS walk order. The depth of the root node is 0.
|
|
///
|
|
/// See [`TaprootBuilder::add_leaf_with_ver`] for adding a leaf with specific version.
|
|
pub fn add_leaf(self, depth: u8, script: ScriptBuf) -> Result<Self, TaprootBuilderError> {
|
|
self.add_leaf_with_ver(depth, script, LeafVersion::TapScript)
|
|
}
|
|
|
|
/// Adds a hidden/omitted node at `depth` to the builder. Errors if the leaves are not provided
|
|
/// in DFS walk order. The depth of the root node is 0.
|
|
pub fn add_hidden_node(
|
|
self,
|
|
depth: u8,
|
|
hash: TapNodeHash,
|
|
) -> Result<Self, TaprootBuilderError> {
|
|
let node = NodeInfo::new_hidden_node(hash);
|
|
self.insert(node, depth)
|
|
}
|
|
|
|
/// Checks if the builder has finalized building a tree.
|
|
pub fn is_finalizable(&self) -> bool { self.branch.len() == 1 && self.branch[0].is_some() }
|
|
|
|
/// Converts the builder into a [`NodeInfo`] if the builder is a full tree with possibly
|
|
/// hidden nodes
|
|
///
|
|
/// # Errors:
|
|
///
|
|
/// [`IncompleteBuilder::NotFinalized`] if the builder is not finalized. The builder
|
|
/// can be restored by calling [`IncompleteBuilder::into_builder`]
|
|
pub fn try_into_node_info(mut self) -> Result<NodeInfo, IncompleteBuilder> {
|
|
if self.branch().len() != 1 {
|
|
return Err(IncompleteBuilder::NotFinalized(self));
|
|
}
|
|
Ok(self
|
|
.branch
|
|
.pop()
|
|
.expect("length checked above")
|
|
.expect("invariant guarantees node info exists"))
|
|
}
|
|
|
|
/// Converts the builder into a [`TapTree`] if the builder is a full tree and
|
|
/// does not contain any hidden nodes
|
|
pub fn try_into_taptree(self) -> Result<TapTree, IncompleteBuilder> {
|
|
let node = self.try_into_node_info()?;
|
|
if node.has_hidden_nodes {
|
|
// Reconstruct the builder as it was if it has hidden nodes
|
|
return Err(IncompleteBuilder::HiddenParts(TaprootBuilder {
|
|
branch: vec![Some(node)],
|
|
}));
|
|
}
|
|
Ok(TapTree(node))
|
|
}
|
|
|
|
/// Checks if the builder has hidden nodes.
|
|
pub fn has_hidden_nodes(&self) -> bool {
|
|
self.branch.iter().flatten().any(|node| node.has_hidden_nodes)
|
|
}
|
|
|
|
/// Creates a [`TaprootSpendInfo`] with the given internal key.
|
|
///
|
|
/// Returns the unmodified builder as Err if the builder is not finalizable.
|
|
/// See also [`TaprootBuilder::is_finalizable`]
|
|
pub fn finalize<C: secp256k1::Verification>(
|
|
mut self,
|
|
secp: &Secp256k1<C>,
|
|
internal_key: UntweakedPublicKey,
|
|
) -> Result<TaprootSpendInfo, TaprootBuilder> {
|
|
match self.branch.len() {
|
|
0 => Ok(TaprootSpendInfo::new_key_spend(secp, internal_key, None)),
|
|
1 =>
|
|
if let Some(Some(node)) = self.branch.pop() {
|
|
Ok(TaprootSpendInfo::from_node_info(secp, internal_key, node))
|
|
} else {
|
|
unreachable!("Size checked above. Builder guarantees the last element is Some")
|
|
},
|
|
_ => Err(self),
|
|
}
|
|
}
|
|
|
|
pub(crate) fn branch(&self) -> &[Option<NodeInfo>] { &self.branch }
|
|
|
|
/// Inserts a leaf at `depth`.
|
|
fn insert(mut self, mut node: NodeInfo, mut depth: u8) -> Result<Self, TaprootBuilderError> {
|
|
// early error on invalid depth. Though this will be checked later
|
|
// while constructing TaprootMerkelBranch
|
|
if depth as usize > TAPROOT_CONTROL_MAX_NODE_COUNT {
|
|
return Err(TaprootBuilderError::InvalidMerkleTreeDepth(depth as usize));
|
|
}
|
|
// We cannot insert a leaf at a lower depth while a deeper branch is unfinished. Doing
|
|
// so would mean the add_leaf/add_hidden invocations do not correspond to a DFS traversal of a
|
|
// binary tree.
|
|
if (depth as usize + 1) < self.branch.len() {
|
|
return Err(TaprootBuilderError::NodeNotInDfsOrder);
|
|
}
|
|
|
|
while self.branch.len() == depth as usize + 1 {
|
|
let child = match self.branch.pop() {
|
|
None => unreachable!("Len of branch checked to be >= 1"),
|
|
Some(Some(child)) => child,
|
|
// Needs an explicit push to add the None that we just popped.
|
|
// Cannot use .last() because of borrow checker issues.
|
|
Some(None) => {
|
|
self.branch.push(None);
|
|
break;
|
|
} // Cannot combine further
|
|
};
|
|
if depth == 0 {
|
|
// We are trying to combine two nodes at root level.
|
|
// Can't propagate further up than the root
|
|
return Err(TaprootBuilderError::OverCompleteTree);
|
|
}
|
|
node = NodeInfo::combine(node, child)?;
|
|
// Propagate to combine nodes at a lower depth
|
|
depth -= 1;
|
|
}
|
|
|
|
if self.branch.len() < depth as usize + 1 {
|
|
// add enough nodes so that we can insert node at depth `depth`
|
|
let num_extra_nodes = depth as usize + 1 - self.branch.len();
|
|
self.branch.extend((0..num_extra_nodes).map(|_| None));
|
|
}
|
|
// Push the last node to the branch
|
|
self.branch[depth as usize] = Some(node);
|
|
Ok(self)
|
|
}
|
|
}
|
|
|
|
impl Default for TaprootBuilder {
|
|
fn default() -> Self { Self::new() }
|
|
}
|
|
|
|
/// Error happening when [`TapTree`] is constructed from a [`TaprootBuilder`]
|
|
/// having hidden branches or not being finalized.
|
|
#[derive(Clone, Ord, PartialOrd, Eq, PartialEq, Hash, Debug)]
|
|
#[non_exhaustive]
|
|
pub enum IncompleteBuilder {
|
|
/// Indicates an attempt to construct a tap tree from a builder containing incomplete branches.
|
|
NotFinalized(TaprootBuilder),
|
|
/// Indicates an attempt to construct a tap tree from a builder containing hidden parts.
|
|
HiddenParts(TaprootBuilder),
|
|
}
|
|
|
|
impl IncompleteBuilder {
|
|
/// Converts error into the original incomplete [`TaprootBuilder`] instance.
|
|
pub fn into_builder(self) -> TaprootBuilder {
|
|
match self {
|
|
IncompleteBuilder::NotFinalized(builder) | IncompleteBuilder::HiddenParts(builder) =>
|
|
builder,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl core::fmt::Display for IncompleteBuilder {
|
|
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
|
|
f.write_str(match self {
|
|
IncompleteBuilder::NotFinalized(_) =>
|
|
"an attempt to construct a tap tree from a builder containing incomplete branches.",
|
|
IncompleteBuilder::HiddenParts(_) =>
|
|
"an attempt to construct a tap tree from a builder containing hidden parts.",
|
|
})
|
|
}
|
|
}
|
|
|
|
#[cfg(feature = "std")]
|
|
impl std::error::Error for IncompleteBuilder {
|
|
fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
|
|
use self::IncompleteBuilder::*;
|
|
|
|
match self {
|
|
NotFinalized(_) | HiddenParts(_) => None,
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Error happening when [`TapTree`] is constructed from a [`NodeInfo`]
|
|
/// having hidden branches.
|
|
#[derive(Clone, Ord, PartialOrd, Eq, PartialEq, Hash, Debug)]
|
|
#[non_exhaustive]
|
|
pub enum HiddenNodes {
|
|
/// Indicates an attempt to construct a tap tree from a builder containing hidden parts.
|
|
HiddenParts(NodeInfo),
|
|
}
|
|
|
|
impl HiddenNodes {
|
|
/// Converts error into the original incomplete [`NodeInfo`] instance.
|
|
pub fn into_node_info(self) -> NodeInfo {
|
|
match self {
|
|
HiddenNodes::HiddenParts(node_info) => node_info,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl core::fmt::Display for HiddenNodes {
|
|
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
|
|
f.write_str(match self {
|
|
HiddenNodes::HiddenParts(_) =>
|
|
"an attempt to construct a tap tree from a node_info containing hidden parts.",
|
|
})
|
|
}
|
|
}
|
|
|
|
#[cfg(feature = "std")]
|
|
impl std::error::Error for HiddenNodes {
|
|
fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
|
|
use self::HiddenNodes::*;
|
|
|
|
match self {
|
|
HiddenParts(_) => None,
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Taproot Tree representing a complete binary tree without any hidden nodes.
|
|
///
|
|
/// This is in contrast to [`NodeInfo`], which allows hidden nodes.
|
|
/// The implementations for Eq, PartialEq and Hash compare the merkle root of the tree
|
|
//
|
|
// This is a bug in BIP370 that does not specify how to share trees with hidden nodes,
|
|
// for which we need a separate type.
|
|
#[derive(Clone, Debug, Eq, PartialEq, Hash)]
|
|
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
|
|
#[cfg_attr(feature = "serde", serde(crate = "actual_serde"))]
|
|
#[cfg_attr(feature = "serde", serde(into = "NodeInfo"))]
|
|
#[cfg_attr(feature = "serde", serde(try_from = "NodeInfo"))]
|
|
pub struct TapTree(NodeInfo);
|
|
|
|
impl From<TapTree> for NodeInfo {
|
|
#[inline]
|
|
fn from(tree: TapTree) -> Self { tree.into_node_info() }
|
|
}
|
|
|
|
impl TapTree {
|
|
/// Gets the reference to inner [`NodeInfo`] of this tree root.
|
|
pub fn node_info(&self) -> &NodeInfo { &self.0 }
|
|
|
|
/// Gets the inner [`NodeInfo`] of this tree root.
|
|
pub fn into_node_info(self) -> NodeInfo { self.0 }
|
|
|
|
/// Returns [`TapTreeIter<'_>`] iterator for a taproot script tree, operating in DFS order over
|
|
/// tree [`ScriptLeaf`]s.
|
|
pub fn script_leaves(&self) -> ScriptLeaves { ScriptLeaves { leaf_iter: self.0.leaf_nodes() } }
|
|
}
|
|
|
|
impl TryFrom<TaprootBuilder> for TapTree {
|
|
type Error = IncompleteBuilder;
|
|
|
|
/// Constructs [`TapTree`] from a [`TaprootBuilder`] if it is complete binary tree.
|
|
///
|
|
/// # Returns
|
|
///
|
|
/// A [`TapTree`] iff the `builder` is complete, otherwise return [`IncompleteBuilder`]
|
|
/// error with the content of incomplete `builder` instance.
|
|
fn try_from(builder: TaprootBuilder) -> Result<Self, Self::Error> { builder.try_into_taptree() }
|
|
}
|
|
|
|
impl TryFrom<NodeInfo> for TapTree {
|
|
type Error = HiddenNodes;
|
|
|
|
/// Constructs [`TapTree`] from a [`NodeInfo`] if it is complete binary tree.
|
|
///
|
|
/// # Returns
|
|
///
|
|
/// A [`TapTree`] iff the [`NodeInfo`] has no hidden nodes, otherwise return [`HiddenNodes`]
|
|
/// error with the content of incomplete [`NodeInfo`] instance.
|
|
fn try_from(node_info: NodeInfo) -> Result<Self, Self::Error> {
|
|
if node_info.has_hidden_nodes {
|
|
Err(HiddenNodes::HiddenParts(node_info))
|
|
} else {
|
|
Ok(TapTree(node_info))
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Iterator for a taproot script tree, operating in DFS order yielding [`ScriptLeaf`].
|
|
///
|
|
/// Returned by [`TapTree::script_leaves`]. [`TapTree`] does not allow hidden nodes,
|
|
/// so this iterator is guaranteed to yield all known leaves.
|
|
pub struct ScriptLeaves<'tree> {
|
|
leaf_iter: LeafNodes<'tree>,
|
|
}
|
|
|
|
impl<'tree> Iterator for ScriptLeaves<'tree> {
|
|
type Item = ScriptLeaf<'tree>;
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<Self::Item> { ScriptLeaf::from_leaf_node(self.leaf_iter.next()?) }
|
|
|
|
fn size_hint(&self) -> (usize, Option<usize>) { self.leaf_iter.size_hint() }
|
|
}
|
|
|
|
impl<'tree> ExactSizeIterator for ScriptLeaves<'tree> {}
|
|
|
|
impl<'tree> FusedIterator for ScriptLeaves<'tree> {}
|
|
|
|
impl<'tree> DoubleEndedIterator for ScriptLeaves<'tree> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<Self::Item> {
|
|
ScriptLeaf::from_leaf_node(self.leaf_iter.next_back()?)
|
|
}
|
|
}
|
|
/// Iterator for a taproot script tree, operating in DFS order yielding [`LeafNode`].
|
|
///
|
|
/// Returned by [`NodeInfo::leaf_nodes`]. This can potentially yield hidden nodes.
|
|
pub struct LeafNodes<'a> {
|
|
leaf_iter: core::slice::Iter<'a, LeafNode>,
|
|
}
|
|
|
|
impl<'a> Iterator for LeafNodes<'a> {
|
|
type Item = &'a LeafNode;
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<Self::Item> { self.leaf_iter.next() }
|
|
|
|
fn size_hint(&self) -> (usize, Option<usize>) { self.leaf_iter.size_hint() }
|
|
}
|
|
|
|
impl<'tree> ExactSizeIterator for LeafNodes<'tree> {}
|
|
|
|
impl<'tree> FusedIterator for LeafNodes<'tree> {}
|
|
|
|
impl<'tree> DoubleEndedIterator for LeafNodes<'tree> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<Self::Item> { self.leaf_iter.next_back() }
|
|
}
|
|
/// Represents the node information in taproot tree. In contrast to [`TapTree`], this
|
|
/// is allowed to have hidden leaves as children.
|
|
///
|
|
/// Helper type used in merkle tree construction allowing one to build sparse merkle trees. The node
|
|
/// represents part of the tree that has information about all of its descendants.
|
|
/// See how [`TaprootBuilder`] works for more details.
|
|
///
|
|
/// You can use [`TaprootSpendInfo::from_node_info`] to a get a [`TaprootSpendInfo`] from the merkle
|
|
/// root [`NodeInfo`].
|
|
#[derive(Debug, Clone, PartialOrd, Ord)]
|
|
pub struct NodeInfo {
|
|
/// Merkle hash for this node.
|
|
pub(crate) hash: TapNodeHash,
|
|
/// Information about leaves inside this node.
|
|
pub(crate) leaves: Vec<LeafNode>,
|
|
/// Tracks information on hidden nodes below this node.
|
|
pub(crate) has_hidden_nodes: bool,
|
|
}
|
|
|
|
impl PartialEq for NodeInfo {
|
|
fn eq(&self, other: &Self) -> bool { self.hash.eq(&other.hash) }
|
|
}
|
|
|
|
impl core::hash::Hash for NodeInfo {
|
|
fn hash<H: core::hash::Hasher>(&self, state: &mut H) { self.hash.hash(state) }
|
|
}
|
|
|
|
impl Eq for NodeInfo {}
|
|
|
|
impl NodeInfo {
|
|
/// Creates a new [`NodeInfo`] with omitted/hidden info.
|
|
pub fn new_hidden_node(hash: TapNodeHash) -> Self {
|
|
Self { hash, leaves: vec![], has_hidden_nodes: true }
|
|
}
|
|
|
|
/// Creates a new leaf [`NodeInfo`] with given [`ScriptBuf`] and [`LeafVersion`].
|
|
pub fn new_leaf_with_ver(script: ScriptBuf, ver: LeafVersion) -> Self {
|
|
Self {
|
|
hash: TapNodeHash::from_script(&script, ver),
|
|
leaves: vec![LeafNode::new_script(script, ver)],
|
|
has_hidden_nodes: false,
|
|
}
|
|
}
|
|
|
|
/// Combines two [`NodeInfo`] to create a new parent.
|
|
pub fn combine(a: Self, b: Self) -> Result<Self, TaprootBuilderError> {
|
|
let mut all_leaves = Vec::with_capacity(a.leaves.len() + b.leaves.len());
|
|
let (hash, left_first) = TapNodeHash::combine_node_hashes(a.hash, b.hash);
|
|
let (a, b) = if left_first { (a, b) } else { (b, a) };
|
|
for mut a_leaf in a.leaves {
|
|
a_leaf.merkle_branch.push(b.hash)?; // add hashing partner
|
|
all_leaves.push(a_leaf);
|
|
}
|
|
for mut b_leaf in b.leaves {
|
|
b_leaf.merkle_branch.push(a.hash)?; // add hashing partner
|
|
all_leaves.push(b_leaf);
|
|
}
|
|
Ok(Self {
|
|
hash,
|
|
leaves: all_leaves,
|
|
has_hidden_nodes: a.has_hidden_nodes || b.has_hidden_nodes,
|
|
})
|
|
}
|
|
|
|
/// Creates an iterator over all leaves (including hidden leaves) in the tree.
|
|
pub fn leaf_nodes(&self) -> LeafNodes { LeafNodes { leaf_iter: self.leaves.iter() } }
|
|
}
|
|
|
|
impl TryFrom<TaprootBuilder> for NodeInfo {
|
|
type Error = IncompleteBuilder;
|
|
|
|
fn try_from(builder: TaprootBuilder) -> Result<Self, Self::Error> {
|
|
builder.try_into_node_info()
|
|
}
|
|
}
|
|
|
|
#[cfg(feature = "serde")]
|
|
impl serde::Serialize for NodeInfo {
|
|
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
|
|
where
|
|
S: serde::Serializer,
|
|
{
|
|
use serde::ser::SerializeSeq;
|
|
let mut seq = serializer.serialize_seq(Some(self.leaves.len() * 2))?;
|
|
for tap_leaf in self.leaves.iter() {
|
|
seq.serialize_element(&tap_leaf.merkle_branch().len())?;
|
|
seq.serialize_element(&tap_leaf.leaf)?;
|
|
}
|
|
seq.end()
|
|
}
|
|
}
|
|
|
|
#[cfg(feature = "serde")]
|
|
impl<'de> serde::Deserialize<'de> for NodeInfo {
|
|
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
|
|
where
|
|
D: serde::Deserializer<'de>,
|
|
{
|
|
struct SeqVisitor;
|
|
impl<'de> serde::de::Visitor<'de> for SeqVisitor {
|
|
type Value = NodeInfo;
|
|
|
|
fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
|
|
formatter.write_str("Taproot tree in DFS walk order")
|
|
}
|
|
|
|
fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
|
|
where
|
|
A: serde::de::SeqAccess<'de>,
|
|
{
|
|
let size = seq
|
|
.size_hint()
|
|
.map(|x| core::mem::size_of::<usize>() * 8 - x.leading_zeros() as usize)
|
|
.map(|x| x / 2) // Each leaf is serialized as two elements.
|
|
.unwrap_or(0)
|
|
.min(TAPROOT_CONTROL_MAX_NODE_COUNT); // no more than 128 nodes
|
|
let mut builder = TaprootBuilder::with_capacity(size);
|
|
while let Some(depth) = seq.next_element()? {
|
|
let tap_leaf: TapLeaf = seq
|
|
.next_element()?
|
|
.ok_or_else(|| serde::de::Error::custom("Missing tap_leaf"))?;
|
|
match tap_leaf {
|
|
TapLeaf::Script(script, ver) => {
|
|
builder =
|
|
builder.add_leaf_with_ver(depth, script, ver).map_err(|e| {
|
|
serde::de::Error::custom(format!("Leaf insertion error: {}", e))
|
|
})?;
|
|
}
|
|
TapLeaf::Hidden(h) => {
|
|
builder = builder.add_hidden_node(depth, h).map_err(|e| {
|
|
serde::de::Error::custom(format!(
|
|
"Hidden node insertion error: {}",
|
|
e
|
|
))
|
|
})?;
|
|
}
|
|
}
|
|
}
|
|
NodeInfo::try_from(builder).map_err(|e| {
|
|
serde::de::Error::custom(format!("Incomplete taproot tree: {}", e))
|
|
})
|
|
}
|
|
}
|
|
|
|
deserializer.deserialize_seq(SeqVisitor)
|
|
}
|
|
}
|
|
|
|
/// Leaf node in a taproot tree. Can be either hidden or known.
|
|
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
|
|
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
|
|
#[cfg_attr(feature = "serde", serde(crate = "actual_serde"))]
|
|
pub enum TapLeaf {
|
|
/// A known script
|
|
Script(ScriptBuf, LeafVersion),
|
|
/// Hidden Node with the given leaf hash
|
|
Hidden(TapNodeHash),
|
|
}
|
|
|
|
impl TapLeaf {
|
|
/// Obtains the hidden leaf hash if the leaf is hidden.
|
|
pub fn as_hidden(&self) -> Option<&TapNodeHash> {
|
|
if let Self::Hidden(v) = self {
|
|
Some(v)
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
|
|
/// Obtains a reference to script and version if the leaf is known.
|
|
pub fn as_script(&self) -> Option<(&Script, LeafVersion)> {
|
|
if let Self::Script(script, ver) = self {
|
|
Some((script, *ver))
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Store information about taproot leaf node.
|
|
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
|
|
pub struct LeafNode {
|
|
/// The [`TapLeaf`]
|
|
leaf: TapLeaf,
|
|
/// The merkle proof (hashing partners) to get this node.
|
|
merkle_branch: TaprootMerkleBranch,
|
|
}
|
|
|
|
impl LeafNode {
|
|
/// Creates an new [`ScriptLeaf`] from `script` and `ver` and no merkle branch.
|
|
pub fn new_script(script: ScriptBuf, ver: LeafVersion) -> Self {
|
|
Self { leaf: TapLeaf::Script(script, ver), merkle_branch: TaprootMerkleBranch(vec![]) }
|
|
}
|
|
|
|
/// Creates an new [`ScriptLeaf`] from `hash` and no merkle branch.
|
|
pub fn new_hidden(hash: TapNodeHash) -> Self {
|
|
Self { leaf: TapLeaf::Hidden(hash), merkle_branch: TaprootMerkleBranch(vec![]) }
|
|
}
|
|
|
|
/// Returns the depth of this script leaf in the tap tree.
|
|
#[inline]
|
|
pub fn depth(&self) -> u8 {
|
|
// Depth is guarded by TAPROOT_CONTROL_MAX_NODE_COUNT.
|
|
u8::try_from(self.merkle_branch().0.len()).expect("depth is guaranteed to fit in a u8")
|
|
}
|
|
|
|
/// Computes a leaf hash for this [`ScriptLeaf`] if the leaf is known.
|
|
///
|
|
/// This [`TapLeafHash`] is useful while signing taproot script spends.
|
|
///
|
|
/// See [`LeafNode::node_hash`] for computing the [`TapNodeHash`] which returns the hidden node
|
|
/// hash if the node is hidden.
|
|
#[inline]
|
|
pub fn leaf_hash(&self) -> Option<TapLeafHash> {
|
|
let (script, ver) = self.leaf.as_script()?;
|
|
Some(TapLeafHash::from_script(script, ver))
|
|
}
|
|
|
|
/// Computes the [`TapNodeHash`] for this [`ScriptLeaf`]. This returns the
|
|
/// leaf hash if the leaf is known and the hidden node hash if the leaf is
|
|
/// hidden.
|
|
/// See also, [`LeafNode::leaf_hash`].
|
|
#[inline]
|
|
pub fn node_hash(&self) -> TapNodeHash {
|
|
match self.leaf {
|
|
TapLeaf::Script(ref script, ver) => TapLeafHash::from_script(script, ver).into(),
|
|
TapLeaf::Hidden(ref hash) => *hash,
|
|
}
|
|
}
|
|
|
|
/// Returns reference to the leaf script if the leaf is known.
|
|
#[inline]
|
|
pub fn script(&self) -> Option<&Script> { self.leaf.as_script().map(|x| x.0) }
|
|
|
|
/// Returns leaf version of the script if the leaf is known.
|
|
#[inline]
|
|
pub fn leaf_version(&self) -> Option<LeafVersion> { self.leaf.as_script().map(|x| x.1) }
|
|
|
|
/// Returns reference to the merkle proof (hashing partners) to get this
|
|
/// node in form of [`TaprootMerkleBranch`].
|
|
#[inline]
|
|
pub fn merkle_branch(&self) -> &TaprootMerkleBranch { &self.merkle_branch }
|
|
|
|
/// Returns a reference to the leaf of this [`ScriptLeaf`].
|
|
#[inline]
|
|
pub fn leaf(&self) -> &TapLeaf { &self.leaf }
|
|
}
|
|
|
|
/// Script leaf node in a taproot tree along with the merkle proof to get this node.
|
|
/// Returned by [`TapTree::script_leaves`]
|
|
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
|
|
pub struct ScriptLeaf<'leaf> {
|
|
/// The version of the script leaf.
|
|
version: LeafVersion,
|
|
/// The script.
|
|
script: &'leaf Script,
|
|
/// The merkle proof (hashing partners) to get this node.
|
|
merkle_branch: &'leaf TaprootMerkleBranch,
|
|
}
|
|
|
|
impl<'leaf> ScriptLeaf<'leaf> {
|
|
/// Obtains the version of the script leaf.
|
|
pub fn version(&self) -> LeafVersion { self.version }
|
|
|
|
/// Obtains a reference to the script inside the leaf.
|
|
pub fn script(&self) -> &Script { self.script }
|
|
|
|
/// Obtains a reference to the merkle proof of the leaf.
|
|
pub fn merkle_branch(&self) -> &TaprootMerkleBranch { self.merkle_branch }
|
|
|
|
/// Obtains a script leaf from the leaf node if the leaf is not hidden.
|
|
pub fn from_leaf_node(leaf_node: &'leaf LeafNode) -> Option<Self> {
|
|
let (script, ver) = leaf_node.leaf.as_script()?;
|
|
Some(Self { version: ver, script, merkle_branch: &leaf_node.merkle_branch })
|
|
}
|
|
}
|
|
|
|
/// The merkle proof for inclusion of a tree in a taptree hash.
|
|
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
|
|
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
|
|
#[cfg_attr(feature = "serde", serde(crate = "actual_serde"))]
|
|
#[cfg_attr(feature = "serde", serde(into = "Vec<TapNodeHash>"))]
|
|
#[cfg_attr(feature = "serde", serde(try_from = "Vec<TapNodeHash>"))]
|
|
pub struct TaprootMerkleBranch(Vec<TapNodeHash>);
|
|
|
|
impl TaprootMerkleBranch {
|
|
/// Returns a reference to the inner vector of hashes.
|
|
pub fn as_inner(&self) -> &[TapNodeHash] { &self.0 }
|
|
|
|
/// Returns the number of nodes in this merkle proof.
|
|
pub fn len(&self) -> usize { self.0.len() }
|
|
|
|
/// Checks if this merkle proof is empty.
|
|
pub fn is_empty(&self) -> bool { self.0.is_empty() }
|
|
|
|
/// Decodes bytes from control block.
|
|
///
|
|
/// This reads the branch as encoded in the control block: the concatenated 32B byte chunks -
|
|
/// one for each hash.
|
|
///
|
|
/// # Errors
|
|
///
|
|
/// The function returns an error if the the number of bytes is not an integer multiple of 32 or
|
|
/// if the number of hashes exceeds 128.
|
|
pub fn decode(sl: &[u8]) -> Result<Self, TaprootError> {
|
|
if sl.len() % TAPROOT_CONTROL_NODE_SIZE != 0 {
|
|
Err(TaprootError::InvalidMerkleBranchSize(sl.len()))
|
|
} else if sl.len() > TAPROOT_CONTROL_NODE_SIZE * TAPROOT_CONTROL_MAX_NODE_COUNT {
|
|
Err(TaprootError::InvalidMerkleTreeDepth(sl.len() / TAPROOT_CONTROL_NODE_SIZE))
|
|
} else {
|
|
let inner = sl
|
|
.chunks_exact(TAPROOT_CONTROL_NODE_SIZE)
|
|
.map(|chunk| {
|
|
TapNodeHash::from_slice(chunk)
|
|
.expect("chunks_exact always returns the correct size")
|
|
})
|
|
.collect();
|
|
|
|
Ok(TaprootMerkleBranch(inner))
|
|
}
|
|
}
|
|
|
|
/// Creates a merkle proof from list of hashes.
|
|
///
|
|
/// # Errors
|
|
/// If inner proof length is more than [`TAPROOT_CONTROL_MAX_NODE_COUNT`] (128).
|
|
fn from_collection<T: AsRef<[TapNodeHash]> + Into<Vec<TapNodeHash>>>(
|
|
collection: T,
|
|
) -> Result<Self, TaprootError> {
|
|
if collection.as_ref().len() > TAPROOT_CONTROL_MAX_NODE_COUNT {
|
|
Err(TaprootError::InvalidMerkleTreeDepth(collection.as_ref().len()))
|
|
} else {
|
|
Ok(TaprootMerkleBranch(collection.into()))
|
|
}
|
|
}
|
|
|
|
/// Serializes to a writer.
|
|
///
|
|
/// # Returns
|
|
///
|
|
/// The number of bytes written to the writer.
|
|
pub fn encode<Write: io::Write>(&self, mut writer: Write) -> io::Result<usize> {
|
|
for hash in self.0.iter() {
|
|
writer.write_all(hash.as_ref())?;
|
|
}
|
|
Ok(self.0.len() * TapNodeHash::LEN)
|
|
}
|
|
|
|
/// Serializes `self` as bytes.
|
|
pub fn serialize(&self) -> Vec<u8> {
|
|
self.0.iter().flat_map(|e| e.as_byte_array()).copied().collect::<Vec<u8>>()
|
|
}
|
|
|
|
/// Appends elements to proof.
|
|
fn push(&mut self, h: TapNodeHash) -> Result<(), TaprootBuilderError> {
|
|
if self.0.len() >= TAPROOT_CONTROL_MAX_NODE_COUNT {
|
|
Err(TaprootBuilderError::InvalidMerkleTreeDepth(self.0.len()))
|
|
} else {
|
|
self.0.push(h);
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
/// Returns the inner list of hashes.
|
|
pub fn into_inner(self) -> Vec<TapNodeHash> { self.0 }
|
|
}
|
|
|
|
macro_rules! impl_try_from {
|
|
($from:ty) => {
|
|
impl TryFrom<$from> for TaprootMerkleBranch {
|
|
type Error = TaprootError;
|
|
|
|
/// Creates a merkle proof from list of hashes.
|
|
///
|
|
/// # Errors
|
|
/// If inner proof length is more than [`TAPROOT_CONTROL_MAX_NODE_COUNT`] (128).
|
|
fn try_from(v: $from) -> Result<Self, Self::Error> {
|
|
TaprootMerkleBranch::from_collection(v)
|
|
}
|
|
}
|
|
};
|
|
}
|
|
impl_try_from!(&[TapNodeHash]);
|
|
impl_try_from!(Vec<TapNodeHash>);
|
|
impl_try_from!(Box<[TapNodeHash]>);
|
|
|
|
macro_rules! impl_try_from_array {
|
|
($($len:expr),* $(,)?) => {
|
|
$(
|
|
impl From<[TapNodeHash; $len]> for TaprootMerkleBranch {
|
|
fn from(a: [TapNodeHash; $len]) -> Self {
|
|
Self(a.to_vec())
|
|
}
|
|
}
|
|
)*
|
|
}
|
|
}
|
|
// Implement for all values [0, 128] inclusive.
|
|
//
|
|
// The reason zero is included is that `TaprootMerkleBranch` doesn't contain the hash of the node
|
|
// that's being proven - it's not needed because the script is already right before control block.
|
|
impl_try_from_array!(
|
|
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
|
|
26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49,
|
|
50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73,
|
|
74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97,
|
|
98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116,
|
|
117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128
|
|
);
|
|
|
|
impl From<TaprootMerkleBranch> for Vec<TapNodeHash> {
|
|
fn from(branch: TaprootMerkleBranch) -> Self { branch.0 }
|
|
}
|
|
|
|
/// Control block data structure used in Tapscript satisfaction.
|
|
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
|
|
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
|
|
#[cfg_attr(feature = "serde", serde(crate = "actual_serde"))]
|
|
pub struct ControlBlock {
|
|
/// The tapleaf version.
|
|
pub leaf_version: LeafVersion,
|
|
/// The parity of the output key (NOT THE INTERNAL KEY WHICH IS ALWAYS XONLY).
|
|
pub output_key_parity: secp256k1::Parity,
|
|
/// The internal key.
|
|
pub internal_key: UntweakedPublicKey,
|
|
/// The merkle proof of a script associated with this leaf.
|
|
pub merkle_branch: TaprootMerkleBranch,
|
|
}
|
|
|
|
impl ControlBlock {
|
|
/// Decodes bytes representing a `ControlBlock`.
|
|
///
|
|
/// This is an extra witness element that provides the proof that taproot script pubkey is
|
|
/// correctly computed with some specified leaf hash. This is the last element in taproot
|
|
/// witness when spending a output via script path.
|
|
///
|
|
/// # Errors
|
|
///
|
|
/// - [`TaprootError::InvalidControlBlockSize`] if `sl` is not of size 1 + 32 + 32N for any N >= 0.
|
|
/// - [`TaprootError::InvalidParity`] if first byte of `sl` is not a valid output key parity.
|
|
/// - [`TaprootError::InvalidTaprootLeafVersion`] if first byte of `sl` is not a valid leaf version.
|
|
/// - [`TaprootError::InvalidInternalKey`] if internal key is invalid (first 32 bytes after the parity byte).
|
|
/// - [`TaprootError::InvalidMerkleTreeDepth`] if merkle tree is too deep (more than 128 levels).
|
|
pub fn decode(sl: &[u8]) -> Result<ControlBlock, TaprootError> {
|
|
if sl.len() < TAPROOT_CONTROL_BASE_SIZE
|
|
|| (sl.len() - TAPROOT_CONTROL_BASE_SIZE) % TAPROOT_CONTROL_NODE_SIZE != 0
|
|
{
|
|
return Err(TaprootError::InvalidControlBlockSize(sl.len()));
|
|
}
|
|
let output_key_parity =
|
|
secp256k1::Parity::from_i32((sl[0] & 1) as i32).map_err(TaprootError::InvalidParity)?;
|
|
let leaf_version = LeafVersion::from_consensus(sl[0] & TAPROOT_LEAF_MASK)?;
|
|
let internal_key = UntweakedPublicKey::from_slice(&sl[1..TAPROOT_CONTROL_BASE_SIZE])
|
|
.map_err(TaprootError::InvalidInternalKey)?;
|
|
let merkle_branch = TaprootMerkleBranch::decode(&sl[TAPROOT_CONTROL_BASE_SIZE..])?;
|
|
Ok(ControlBlock { leaf_version, output_key_parity, internal_key, merkle_branch })
|
|
}
|
|
|
|
/// Returns the size of control block. Faster and more efficient than calling
|
|
/// `Self::serialize().len()`. Can be handy for fee estimation.
|
|
pub fn size(&self) -> usize {
|
|
TAPROOT_CONTROL_BASE_SIZE + TAPROOT_CONTROL_NODE_SIZE * self.merkle_branch.as_inner().len()
|
|
}
|
|
|
|
/// Serializes to a writer.
|
|
///
|
|
/// # Returns
|
|
///
|
|
/// The number of bytes written to the writer.
|
|
pub fn encode<Write: io::Write>(&self, mut writer: Write) -> io::Result<usize> {
|
|
let first_byte: u8 =
|
|
i32::from(self.output_key_parity) as u8 | self.leaf_version.to_consensus();
|
|
writer.write_all(&[first_byte])?;
|
|
writer.write_all(&self.internal_key.serialize())?;
|
|
self.merkle_branch.encode(&mut writer)?;
|
|
Ok(self.size())
|
|
}
|
|
|
|
/// Serializes the control block.
|
|
///
|
|
/// This would be required when using [`ControlBlock`] as a witness element while spending an
|
|
/// output via script path. This serialization does not include the [`crate::VarInt`] prefix that would
|
|
/// be applied when encoding this element as a witness.
|
|
pub fn serialize(&self) -> Vec<u8> {
|
|
let mut buf = Vec::with_capacity(self.size());
|
|
self.encode(&mut buf).expect("writers don't error");
|
|
buf
|
|
}
|
|
|
|
/// Verifies that a control block is correct proof for a given output key and script.
|
|
///
|
|
/// Only checks that script is contained inside the taptree described by output key. Full
|
|
/// verification must also execute the script with witness data.
|
|
pub fn verify_taproot_commitment<C: secp256k1::Verification>(
|
|
&self,
|
|
secp: &Secp256k1<C>,
|
|
output_key: XOnlyPublicKey,
|
|
script: &Script,
|
|
) -> bool {
|
|
// compute the script hash
|
|
// Initially the curr_hash is the leaf hash
|
|
let mut curr_hash = TapNodeHash::from_script(script, self.leaf_version);
|
|
// Verify the proof
|
|
for elem in self.merkle_branch.as_inner() {
|
|
// Recalculate the curr hash as parent hash
|
|
curr_hash = TapNodeHash::from_node_hashes(curr_hash, *elem);
|
|
}
|
|
// compute the taptweak
|
|
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)
|
|
}
|
|
}
|
|
|
|
/// Inner type representing future (non-tapscript) leaf versions. See [`LeafVersion::Future`].
|
|
///
|
|
/// NB: NO PUBLIC CONSTRUCTOR!
|
|
/// The only way to construct this is by converting `u8` to [`LeafVersion`] and then extracting it.
|
|
#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash, Ord, PartialOrd)]
|
|
pub struct FutureLeafVersion(u8);
|
|
|
|
impl FutureLeafVersion {
|
|
pub(self) fn from_consensus(version: u8) -> Result<FutureLeafVersion, TaprootError> {
|
|
match version {
|
|
TAPROOT_LEAF_TAPSCRIPT => unreachable!(
|
|
"FutureLeafVersion::from_consensus should be never called for 0xC0 value"
|
|
),
|
|
TAPROOT_ANNEX_PREFIX =>
|
|
Err(TaprootError::InvalidTaprootLeafVersion(TAPROOT_ANNEX_PREFIX)),
|
|
odd if odd & 0xFE != odd => Err(TaprootError::InvalidTaprootLeafVersion(odd)),
|
|
even => Ok(FutureLeafVersion(even)),
|
|
}
|
|
}
|
|
|
|
/// Returns the consensus representation of this [`FutureLeafVersion`].
|
|
#[inline]
|
|
pub fn to_consensus(self) -> u8 { self.0 }
|
|
}
|
|
|
|
impl fmt::Display for FutureLeafVersion {
|
|
#[inline]
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { fmt::Display::fmt(&self.0, f) }
|
|
}
|
|
|
|
impl fmt::LowerHex for FutureLeafVersion {
|
|
#[inline]
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { fmt::LowerHex::fmt(&self.0, f) }
|
|
}
|
|
|
|
impl fmt::UpperHex for FutureLeafVersion {
|
|
#[inline]
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { fmt::UpperHex::fmt(&self.0, f) }
|
|
}
|
|
|
|
/// The leaf version for tapleafs.
|
|
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
|
|
pub enum LeafVersion {
|
|
/// BIP-342 tapscript.
|
|
TapScript,
|
|
|
|
/// Future leaf version.
|
|
Future(FutureLeafVersion),
|
|
}
|
|
|
|
impl LeafVersion {
|
|
/// Creates a [`LeafVersion`] from consensus byte representation.
|
|
///
|
|
/// # Errors
|
|
///
|
|
/// - If the last bit of the `version` is odd.
|
|
/// - If the `version` is 0x50 ([`TAPROOT_ANNEX_PREFIX`]).
|
|
pub fn from_consensus(version: u8) -> Result<Self, TaprootError> {
|
|
match version {
|
|
TAPROOT_LEAF_TAPSCRIPT => Ok(LeafVersion::TapScript),
|
|
TAPROOT_ANNEX_PREFIX =>
|
|
Err(TaprootError::InvalidTaprootLeafVersion(TAPROOT_ANNEX_PREFIX)),
|
|
future => FutureLeafVersion::from_consensus(future).map(LeafVersion::Future),
|
|
}
|
|
}
|
|
|
|
/// Returns the consensus representation of this [`LeafVersion`].
|
|
pub fn to_consensus(self) -> u8 {
|
|
match self {
|
|
LeafVersion::TapScript => TAPROOT_LEAF_TAPSCRIPT,
|
|
LeafVersion::Future(version) => version.to_consensus(),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl fmt::Display for LeafVersion {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
match (self, f.alternate()) {
|
|
(LeafVersion::TapScript, true) => f.write_str("tapscript"),
|
|
(LeafVersion::TapScript, false) => fmt::Display::fmt(&TAPROOT_LEAF_TAPSCRIPT, f),
|
|
(LeafVersion::Future(version), true) => write!(f, "future_script_{:#02x}", version.0),
|
|
(LeafVersion::Future(version), false) => fmt::Display::fmt(version, f),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl fmt::LowerHex for LeafVersion {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
fmt::LowerHex::fmt(&self.to_consensus(), f)
|
|
}
|
|
}
|
|
|
|
impl fmt::UpperHex for LeafVersion {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
fmt::UpperHex::fmt(&self.to_consensus(), f)
|
|
}
|
|
}
|
|
|
|
/// Serializes [`LeafVersion`] as a `u8` using consensus encoding.
|
|
#[cfg(feature = "serde")]
|
|
impl serde::Serialize for LeafVersion {
|
|
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
|
|
where
|
|
S: serde::Serializer,
|
|
{
|
|
serializer.serialize_u8(self.to_consensus())
|
|
}
|
|
}
|
|
|
|
/// Deserializes [`LeafVersion`] as a `u8` using consensus encoding.
|
|
#[cfg(feature = "serde")]
|
|
impl<'de> serde::Deserialize<'de> for LeafVersion {
|
|
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
|
|
where
|
|
D: serde::Deserializer<'de>,
|
|
{
|
|
struct U8Visitor;
|
|
impl<'de> serde::de::Visitor<'de> for U8Visitor {
|
|
type Value = LeafVersion;
|
|
|
|
fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
|
|
formatter.write_str("a valid consensus-encoded taproot leaf version")
|
|
}
|
|
|
|
fn visit_u64<E>(self, value: u64) -> Result<Self::Value, E>
|
|
where
|
|
E: serde::de::Error,
|
|
{
|
|
let value = u8::try_from(value).map_err(|_| {
|
|
E::invalid_value(
|
|
serde::de::Unexpected::Unsigned(value),
|
|
&"consensus-encoded leaf version as u8",
|
|
)
|
|
})?;
|
|
LeafVersion::from_consensus(value).map_err(|_| {
|
|
E::invalid_value(
|
|
::serde::de::Unexpected::Unsigned(value as u64),
|
|
&"consensus-encoded leaf version as u8",
|
|
)
|
|
})
|
|
}
|
|
}
|
|
|
|
deserializer.deserialize_u8(U8Visitor)
|
|
}
|
|
}
|
|
|
|
/// Detailed error type for taproot builder.
|
|
#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
|
|
#[non_exhaustive]
|
|
pub enum TaprootBuilderError {
|
|
/// Merkle tree depth must not be more than 128.
|
|
InvalidMerkleTreeDepth(usize),
|
|
/// Nodes must be added specified in DFS walk order.
|
|
NodeNotInDfsOrder,
|
|
/// Two nodes at depth 0 are not allowed.
|
|
OverCompleteTree,
|
|
/// Invalid taproot internal key.
|
|
InvalidInternalKey(secp256k1::Error),
|
|
/// Called finalize on a empty tree.
|
|
EmptyTree,
|
|
}
|
|
|
|
impl fmt::Display for TaprootBuilderError {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
match *self {
|
|
TaprootBuilderError::InvalidMerkleTreeDepth(d) => {
|
|
write!(
|
|
f,
|
|
"Merkle Tree depth({}) must be less than {}",
|
|
d, TAPROOT_CONTROL_MAX_NODE_COUNT
|
|
)
|
|
}
|
|
TaprootBuilderError::NodeNotInDfsOrder => {
|
|
write!(f, "add_leaf/add_hidden must be called in DFS walk order",)
|
|
}
|
|
TaprootBuilderError::OverCompleteTree => write!(
|
|
f,
|
|
"Attempted to create a tree with two nodes at depth 0. There must\
|
|
only be a exactly one node at depth 0",
|
|
),
|
|
TaprootBuilderError::InvalidInternalKey(ref e) => {
|
|
write_err!(f, "invalid internal x-only key"; e)
|
|
}
|
|
TaprootBuilderError::EmptyTree => {
|
|
write!(f, "Called finalize on an empty tree")
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#[cfg(feature = "std")]
|
|
impl std::error::Error for TaprootBuilderError {
|
|
fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
|
|
use self::TaprootBuilderError::*;
|
|
|
|
match self {
|
|
InvalidInternalKey(e) => Some(e),
|
|
InvalidMerkleTreeDepth(_) | NodeNotInDfsOrder | OverCompleteTree | EmptyTree => None,
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Detailed error type for taproot utilities.
|
|
#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
|
|
#[non_exhaustive]
|
|
pub enum TaprootError {
|
|
/// Proof size must be a multiple of 32.
|
|
InvalidMerkleBranchSize(usize),
|
|
/// Merkle tree depth must not be more than 128.
|
|
InvalidMerkleTreeDepth(usize),
|
|
/// The last bit of tapleaf version must be zero.
|
|
InvalidTaprootLeafVersion(u8),
|
|
/// Invalid control block size.
|
|
InvalidControlBlockSize(usize),
|
|
/// Invalid taproot internal key.
|
|
InvalidInternalKey(secp256k1::Error),
|
|
/// Invalid parity for internal key.
|
|
InvalidParity(secp256k1::InvalidParityValue),
|
|
/// Empty tap tree.
|
|
EmptyTree,
|
|
}
|
|
|
|
impl fmt::Display for TaprootError {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
match *self {
|
|
TaprootError::InvalidMerkleBranchSize(sz) => write!(
|
|
f,
|
|
"Merkle branch size({}) must be a multiple of {}",
|
|
sz, TAPROOT_CONTROL_NODE_SIZE
|
|
),
|
|
TaprootError::InvalidMerkleTreeDepth(d) => write!(
|
|
f,
|
|
"Merkle Tree depth({}) must be less than {}",
|
|
d, TAPROOT_CONTROL_MAX_NODE_COUNT
|
|
),
|
|
TaprootError::InvalidTaprootLeafVersion(v) => {
|
|
write!(f, "Leaf version({}) must have the least significant bit 0", v)
|
|
}
|
|
TaprootError::InvalidControlBlockSize(sz) => write!(
|
|
f,
|
|
"Control Block size({}) must be of the form 33 + 32*m where 0 <= m <= {} ",
|
|
sz, TAPROOT_CONTROL_MAX_NODE_COUNT
|
|
),
|
|
TaprootError::InvalidInternalKey(ref e) => {
|
|
write_err!(f, "invalid internal x-only key"; e)
|
|
}
|
|
TaprootError::InvalidParity(_) => write!(f, "invalid parity value for internal key"),
|
|
TaprootError::EmptyTree => write!(f, "Taproot Tree must contain at least one script"),
|
|
}
|
|
}
|
|
}
|
|
|
|
#[cfg(feature = "std")]
|
|
impl std::error::Error for TaprootError {
|
|
fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
|
|
use self::TaprootError::*;
|
|
|
|
match self {
|
|
InvalidInternalKey(e) => Some(e),
|
|
InvalidMerkleBranchSize(_)
|
|
| InvalidMerkleTreeDepth(_)
|
|
| InvalidTaprootLeafVersion(_)
|
|
| InvalidControlBlockSize(_)
|
|
| InvalidParity(_)
|
|
| EmptyTree => None,
|
|
}
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod test {
|
|
use core::str::FromStr;
|
|
|
|
use hashes::hex::FromHex;
|
|
use hashes::sha256t::Tag;
|
|
use hashes::{sha256, Hash, HashEngine};
|
|
use secp256k1::{VerifyOnly, XOnlyPublicKey};
|
|
|
|
use super::*;
|
|
use crate::sighash::{TapSighash, TapSighashTag};
|
|
use crate::{Address, Network};
|
|
extern crate serde_json;
|
|
|
|
#[cfg(feature = "serde")]
|
|
use {
|
|
crate::internal_macros::hex,
|
|
serde_test::Configure,
|
|
serde_test::{assert_tokens, Token},
|
|
};
|
|
|
|
fn tag_engine(tag_name: &str) -> sha256::HashEngine {
|
|
let mut engine = sha256::Hash::engine();
|
|
let tag_hash = sha256::Hash::hash(tag_name.as_bytes());
|
|
engine.input(tag_hash.as_ref());
|
|
engine.input(tag_hash.as_ref());
|
|
engine
|
|
}
|
|
|
|
#[test]
|
|
fn test_midstates() {
|
|
// test that engine creation roundtrips
|
|
assert_eq!(tag_engine("TapLeaf").midstate(), TapLeafTag::engine().midstate());
|
|
assert_eq!(tag_engine("TapBranch").midstate(), TapBranchTag::engine().midstate());
|
|
assert_eq!(tag_engine("TapTweak").midstate(), TapTweakTag::engine().midstate());
|
|
assert_eq!(tag_engine("TapSighash").midstate(), TapSighashTag::engine().midstate());
|
|
|
|
// check that hash creation is the same as building into the same engine
|
|
fn empty_hash(tag_name: &str) -> [u8; 32] {
|
|
let mut e = tag_engine(tag_name);
|
|
e.input(&[]);
|
|
TapNodeHash::from_engine(e).to_byte_array()
|
|
}
|
|
assert_eq!(empty_hash("TapLeaf"), TapLeafHash::hash(&[]).to_byte_array());
|
|
assert_eq!(empty_hash("TapBranch"), TapNodeHash::hash(&[]).to_byte_array());
|
|
assert_eq!(empty_hash("TapTweak"), TapTweakHash::hash(&[]).to_byte_array());
|
|
assert_eq!(empty_hash("TapSighash"), TapSighash::hash(&[]).to_byte_array());
|
|
}
|
|
|
|
#[test]
|
|
fn test_vectors_core() {
|
|
//! Test vectors taken from Core
|
|
|
|
// uninitialized writers
|
|
// CHashWriter writer = HasherTapLeaf;
|
|
// writer.GetSHA256().GetHex()
|
|
assert_eq!(
|
|
TapLeafHash::from_engine(TapLeafTag::engine()).to_string(),
|
|
"5212c288a377d1f8164962a5a13429f9ba6a7b84e59776a52c6637df2106facb"
|
|
);
|
|
assert_eq!(
|
|
TapNodeHash::from_engine(TapBranchTag::engine()).to_string(),
|
|
"53c373ec4d6f3c53c1f5fb2ff506dcefe1a0ed74874f93fa93c8214cbe9ffddf"
|
|
);
|
|
assert_eq!(
|
|
TapTweakHash::from_engine(TapTweakTag::engine()).to_string(),
|
|
"8aa4229474ab0100b2d6f0687f031d1fc9d8eef92a042ad97d279bff456b15e4"
|
|
);
|
|
assert_eq!(
|
|
TapSighash::from_engine(TapSighashTag::engine()).to_string(),
|
|
"dabc11914abcd8072900042a2681e52f8dba99ce82e224f97b5fdb7cd4b9c803"
|
|
);
|
|
|
|
// 0-byte
|
|
// CHashWriter writer = HasherTapLeaf;
|
|
// writer << std::vector<unsigned char>{};
|
|
// writer.GetSHA256().GetHex()
|
|
// Note that Core writes the 0 length prefix when an empty vector is written.
|
|
assert_eq!(
|
|
TapLeafHash::hash(&[0]).to_string(),
|
|
"ed1382037800c9dd938dd8854f1a8863bcdeb6705069b4b56a66ec22519d5829"
|
|
);
|
|
assert_eq!(
|
|
TapNodeHash::hash(&[0]).to_string(),
|
|
"92534b1960c7e6245af7d5fda2588db04aa6d646abc2b588dab2b69e5645eb1d"
|
|
);
|
|
assert_eq!(
|
|
TapTweakHash::hash(&[0]).to_string(),
|
|
"cd8737b5e6047fc3f16f03e8b9959e3440e1bdf6dd02f7bb899c352ad490ea1e"
|
|
);
|
|
assert_eq!(
|
|
TapSighash::hash(&[0]).to_string(),
|
|
"c2fd0de003889a09c4afcf676656a0d8a1fb706313ff7d509afb00c323c010cd"
|
|
);
|
|
}
|
|
|
|
fn _verify_tap_commitments(
|
|
secp: &Secp256k1<VerifyOnly>,
|
|
out_spk_hex: &str,
|
|
script_hex: &str,
|
|
control_block_hex: &str,
|
|
) {
|
|
let out_pk = XOnlyPublicKey::from_str(&out_spk_hex[4..]).unwrap();
|
|
let out_pk = TweakedPublicKey::dangerous_assume_tweaked(out_pk);
|
|
let script = ScriptBuf::from_hex(script_hex).unwrap();
|
|
let control_block =
|
|
ControlBlock::decode(&Vec::<u8>::from_hex(control_block_hex).unwrap()).unwrap();
|
|
assert_eq!(control_block_hex, control_block.serialize().to_lower_hex_string());
|
|
assert!(control_block.verify_taproot_commitment(secp, out_pk.to_inner(), &script));
|
|
}
|
|
|
|
#[test]
|
|
fn control_block_verify() {
|
|
let secp = Secp256k1::verification_only();
|
|
// test vectors obtained from printing values in feature_taproot.py from Bitcoin Core
|
|
_verify_tap_commitments(&secp, "51205dc8e62b15e0ebdf44751676be35ba32eed2e84608b290d4061bbff136cd7ba9", "6a", "c1a9d6f66cd4b25004f526bfa873e56942f98e8e492bd79ed6532b966104817c2bda584e7d32612381cf88edc1c02e28a296e807c16ad22f591ee113946e48a71e0641e660d1e5392fb79d64838c2b84faf04b7f5f283c9d8bf83e39e177b64372a0cd22eeab7e093873e851e247714eff762d8a30be699ba4456cfe6491b282e193a071350ae099005a5950d74f73ba13077a57bc478007fb0e4d1099ce9cf3d4");
|
|
_verify_tap_commitments(&secp, "5120e208c869c40d8827101c5ad3238018de0f3f5183d77a0c53d18ac28ddcbcd8ad", "f4", "c0a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f40090ab1f4890d51115998242ebce636efb9ede1b516d9eb8952dc1068e0335306199aaf103cceb41d9bc37ec231aca89b984b5fd3c65977ce764d51033ac65adb4da14e029b1e154a85bfd9139e7aa2720b6070a4ceba8264ca61d5d3ac27aceb9ef4b54cd43c2d1fd5e11b5c2e93cf29b91ea3dc5b832201f02f7473a28c63246");
|
|
_verify_tap_commitments(
|
|
&secp,
|
|
"5120567666e7df90e0450bb608e17c01ed3fbcfa5355a5f8273e34e583bfaa70ce09",
|
|
"203455139bf238a3067bd72ed77e0ab8db590330f55ed58dba7366b53bf4734279ac",
|
|
"c1a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f400",
|
|
);
|
|
_verify_tap_commitments(&secp, "5120580a19e47269414a55eb86d5d0c6c9b371455d9fd2154412a57dec840df99fe1", "6a", "bca0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f40042ba1bd1c63c03ccff60d4c4d53a653f87909eb3358e7fa45c9d805231fb08c933e1f4e0f9d17f591df1419df7d5b7eb5f744f404c5ef9ecdb1b89b18cafa3a816d8b5dba3205f9a9c05f866d91f40d2793a7586d502cb42f46c7a11f66ad4aa");
|
|
_verify_tap_commitments(&secp, "5120228b94a4806254a38d6efa8a134c28ebc89546209559dfe40b2b0493bafacc5b", "6a50", "c0a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f4009c9aed3dfd11ab0e78bf87ef3bf296269dc4b0f7712140386d6980992bab4b45");
|
|
_verify_tap_commitments(
|
|
&secp,
|
|
"5120567666e7df90e0450bb608e17c01ed3fbcfa5355a5f8273e34e583bfaa70ce09",
|
|
"203455139bf238a3067bd72ed77e0ab8db590330f55ed58dba7366b53bf4734279ac",
|
|
"c1a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f400",
|
|
);
|
|
_verify_tap_commitments(
|
|
&secp,
|
|
"5120b0a79103c31fe51eea61d2873bad8a25a310da319d7e7a85f825fa7a00ea3f85",
|
|
"203455139bf238a3067bd72ed77e0ab8db590330f55ed58dba7366b53bf4734279ad51",
|
|
"c1a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f400",
|
|
);
|
|
_verify_tap_commitments(&secp, "5120f2f62e854a0012aeba78cd4ba4a0832447a5262d4c6eb4f1c95c7914b536fc6c", "6a86", "c1a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f4009ad3d30479f0689dbdf59a6b840d60ad485b2effbed1825a75ce19a44e460e09056f60ea686d79cfa4fb79f197b2e905ac857a983be4a5a41a4873e865aa950780c0237de279dc063e67deec46ef8e1bc351bf12c4d67a6d568001faf097e797e6ee620f53cfe0f8acaddf2063c39c3577853bb46d61ffcba5a024c3e1216837");
|
|
_verify_tap_commitments(&secp, "51202a4772070b49bae68b44315032cdbf9c40c7c2f896781b32b931b73dbfb26d7e", "6af8", "c0a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f4006f183944a14618fc7fe9ceade0f58e43a19d3c3b179ea6c43c29616413b6971c99aaf103cceb41d9bc37ec231aca89b984b5fd3c65977ce764d51033ac65adb4c3462adec78cd04f3cc156bdadec50def99feae0dc6a23664e8a2b0d42d6ca9eb968dfdf46c23af642b2688351904e0a0630e71ffac5bcaba33b9b2c8a7495ec");
|
|
_verify_tap_commitments(&secp, "5120a32b0b8cfafe0f0f8d5870030ba4d19a8725ad345cb3c8420f86ac4e0dff6207", "4c", "e8a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f400615da7ac8d078e5fc7f4690fc2127ba40f0f97cc070ade5b3a7919783d91ef3f13734aab908ae998e57848a01268fe8217d70bc3ee8ea8ceae158ae964a4b5f3af20b50d7019bf47fde210eee5c52f1cfe71cfca78f2d3e7c1fd828c80351525");
|
|
_verify_tap_commitments(
|
|
&secp,
|
|
"5120b0a79103c31fe51eea61d2873bad8a25a310da319d7e7a85f825fa7a00ea3f85",
|
|
"203455139bf238a3067bd72ed77e0ab8db590330f55ed58dba7366b53bf4734279ad51",
|
|
"c1a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f400",
|
|
);
|
|
_verify_tap_commitments(&secp, "51208678459f1fa0f80e9b89b8ffdcaf46a022bdf60aa45f1fed9a96145edf4ec400", "6a50", "c0a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f4001eff29e1a89e650076b8d3c56302881d09c9df215774ed99993aaed14acd6615");
|
|
_verify_tap_commitments(&secp, "5120017316303aed02bcdec424c851c9eacbe192b013139bd9634c4e19b3475b06e1", "61", "02a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f40050462265ca552b23cbb4fe021b474313c8cb87d4a18b3f7bdbeb2b418279ba31fc6509d829cd42336f563363cb3538d78758e0876c71e13012eb2b656eb0edb051a2420a840d5c8c6c762abc7410af2c311f606b20ca2ace56a8139f84b1379a");
|
|
_verify_tap_commitments(&secp, "5120896d4d5d2236e86c6e9320e86d1a7822e652907cbd508360e8c71aefc127c77d", "61", "14a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f4001ab0e9d9a4858a0e69605fe9c5a42d739fbe26fa79650e7074f462b02645f7ea1c91802b298cd91e6b5af57c6a013d93397cd2ecbd5569382cc27becf44ff4fff8960b20f846160c159c58350f6b6072cf1b3daa5185b7a42524fb72cbc252576ae46732b8e31ac24bfa7d72f4c3713e8696f99d8ac6c07e4c820a03f249f144");
|
|
_verify_tap_commitments(&secp, "512093c7378d96518a75448821c4f7c8f4bae7ce60f804d03d1f0628dd5dd0f5de51", "04ffffffff203455139bf238a3067bd72ed77e0ab8db590330f55ed58dba7366b53bf4734279ba04feffffff87ab", "c1a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f400c9a5cd1f6c8a81f5648e39f9810591df1c9a8f1fe97c92e03ecd7c0c016c951983e05473c6e8238cb4c780ea2ce62552b2a3eee068ceffc00517cd7b97e10dad");
|
|
_verify_tap_commitments(&secp, "5120b28d75a7179de6feb66b8bb0bfa2b2c739d1a41cf7366a1b393804a844db8a28", "61", "c4a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f400eebc95ded88fb8050094e8dfa958c3be0894eaff0fafae678206b26918d8d7ac47039d40fe34d04b4155df7f1be7f2a49253c7e87812ea9e569e683ac27459e652d6503aa32d64734d00adfee8798b2eed28858abf3bd038e8fa58eb7df4a2d9");
|
|
_verify_tap_commitments(&secp, "512043e4aa733fc6f43c78a31c2b3c192623acf5cc8c01199ebcc4de88067baca83e", "bd4c", "c1a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f4003f7be6f8848b5bddf332c4d7bd83077f73701e2479f70e02b5730e841234d082b8b41ebea96ffd937715d9faeaa6895e6ef3b22919c554b75df12b3371d328023e443d1df50634ecc1cd169803a1e546f0d44304d8fc5056c408e597fed469b8437d6660eaad3cf72e35ba6e5ff7ddd5e293c1e7e813c871df4f46508e9946ec");
|
|
_verify_tap_commitments(&secp, "5120ee9aecb28f5f35ce1f8b5ec80275ac0f81bca4a21b29b4632fb4bcbef8823e6a", "2021a5981b13be29c9d4ea179ea44a8b773ea8c02d68f6f6eefd98de20d4bd055fac", "c13359c284c196b6e80f0cf1d93b6a397cf7ee722f0427b705bd954b88ada8838bd2622fd0e104fc50aa763b43c6a792d7d117029983abd687223b4344a9402c618bba7f5fc3fa8a57491f6842acde88c1e675ca35caea3b1a69ee2c2d9b10f615");
|
|
_verify_tap_commitments(&secp, "5120885274df2252b44764dcef53c21f21154e8488b7e79fafbc96b9ebb22ad0200d", "6a50", "c1a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f4000793597254158918e3369507f2d6fdbef17d18b1028bbb0719450ded0f42c58f");
|
|
_verify_tap_commitments(&secp, "512066f6f6f91d47674d198a28388e1eb05ec24e6ddbba10f16396b1a80c08675121", "6a50", "c1a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f400fe92aff70a2e8e2a4f34a913b99612468a41e0f8ecaff9a729a173d11013c27e");
|
|
_verify_tap_commitments(&secp, "5120868ed9307bd4637491ff03e3aa2c216a08fe213cac8b6cedbb9ab31dbfa6512c", "61", "a2a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f400da584e7d32612381cf88edc1c02e28a296e807c16ad22f591ee113946e48a71e46c7eccffefd2d573ec014130e508f0c9963ccebd7830409f7b1b1301725e9fa759d4ef857ec8e0bb42d6d31609d3c7e77de3bfa28c38f93393a6ddbabe819ec560ed4f061fbe742a5fd2a648d5209469420434c8753da3fa7067cc2bb4c172a");
|
|
_verify_tap_commitments(&secp, "5120c1a00a9baa82888fd7d30291135a7eaa9e9966a5f16db2b10460572f8b108d8d", "0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000", "5ba0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f4007960d7b37dd1361aee34510e77acb4d27ddca17648a17e28475032538c1eb500f5a747f2c0893f79fe153ae918ac3d696de9322aa679aae62051ff5ed83aa502b338bd907346abd4cd9cf06117cb35d55a5a8dd950843522f8de7b5c7fba1804c38b0778d3d76b383f6db6fdf9d6e770da8fffbfa5152c0b8b38129885bcdee6");
|
|
_verify_tap_commitments(&secp, "5120bb9abeff7286b76dfc61800c548fe2621ff47506e47201a85c543b4a9a96fead", "75203455139bf238a3067bd72ed77e0ab8db590330f55ed58dba7366b53bf47342796ead6ead6ead6ead6ead6ead6ead6ead6ead6ead6ead6ead6eadac", "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");
|
|
_verify_tap_commitments(&secp, "5120afddc189ea51094b4cbf463806792e9c8b35dfdc5e01228c78376380d0046b00", "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", "c0a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f400ff698adfda0327f188e2ee35f7aecc0f90c9138a350d450648d968c2b5dd7ef94ddd3ec418dc0d03ee4956feb708d838ed2b20e5a193465a6a1467fd3054e1ea141ea4c4c503a6271e19a090e2a69a24282e3be04c4f98720f7a0eb274d9693d13a8e3c139aa625fa2aefd09854570527f9ac545bda1b689719f5cb715612c07");
|
|
_verify_tap_commitments(&secp, "5120afddc189ea51094b4cbf463806792e9c8b35dfdc5e01228c78376380d0046b00", "83", "c0a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f4007388cda01113397d4cd00bcfbd08fd68c3cfe3a42cbfe3a7651c1d5e6dacf1ad99aaf103cceb41d9bc37ec231aca89b984b5fd3c65977ce764d51033ac65adb4b59764bec92507e4a4c3f01a06f05980163ca10f1c549bfe01f85fa4f109a1295e607f5ed9f1008048474de336f11f67a1fbf2012f58944dede0ab19a3ca81f5");
|
|
_verify_tap_commitments(&secp, "512093c7378d96518a75448821c4f7c8f4bae7ce60f804d03d1f0628dd5dd0f5de51", "04ffffffff203455139bf238a3067bd72ed77e0ab8db590330f55ed58dba7366b53bf4734279ba04feffffff87ab", "c1a0eb12e60a52614986c623cbb6621dcdba3a47e3be6b37e032b7a11c7b98f400c9a5cd1f6c8a81f5648e39f9810591df1c9a8f1fe97c92e03ecd7c0c016c951983e05473c6e8238cb4c780ea2ce62552b2a3eee068ceffc00517cd7b97e10dad");
|
|
}
|
|
|
|
#[test]
|
|
fn build_huffman_tree() {
|
|
let secp = Secp256k1::verification_only();
|
|
let internal_key = UntweakedPublicKey::from_str(
|
|
"93c7378d96518a75448821c4f7c8f4bae7ce60f804d03d1f0628dd5dd0f5de51",
|
|
)
|
|
.unwrap();
|
|
|
|
let script_weights = vec![
|
|
(10, ScriptBuf::from_hex("51").unwrap()), // semantics of script don't matter for this test
|
|
(20, ScriptBuf::from_hex("52").unwrap()),
|
|
(20, ScriptBuf::from_hex("53").unwrap()),
|
|
(30, ScriptBuf::from_hex("54").unwrap()),
|
|
(19, ScriptBuf::from_hex("55").unwrap()),
|
|
];
|
|
let tree_info =
|
|
TaprootSpendInfo::with_huffman_tree(&secp, internal_key, script_weights.clone())
|
|
.unwrap();
|
|
|
|
/* The resulting tree should put the scripts into a tree similar
|
|
* to the following:
|
|
*
|
|
* 1 __/\__
|
|
* / \
|
|
* /\ / \
|
|
* 2 54 52 53 /\
|
|
* 3 55 51
|
|
*/
|
|
|
|
for (script, length) in [("51", 3), ("52", 2), ("53", 2), ("54", 2), ("55", 3)].iter() {
|
|
assert_eq!(
|
|
*length,
|
|
tree_info
|
|
.script_map
|
|
.get(&(ScriptBuf::from_hex(script).unwrap(), LeafVersion::TapScript))
|
|
.expect("Present Key")
|
|
.iter()
|
|
.next()
|
|
.expect("Present Path")
|
|
.0
|
|
.len()
|
|
);
|
|
}
|
|
|
|
// Obtain the output key
|
|
let output_key = tree_info.output_key();
|
|
|
|
// Try to create and verify a control block from each path
|
|
for (_weights, script) in script_weights {
|
|
let ver_script = (script, LeafVersion::TapScript);
|
|
let ctrl_block = tree_info.control_block(&ver_script).unwrap();
|
|
assert!(ctrl_block.verify_taproot_commitment(
|
|
&secp,
|
|
output_key.to_inner(),
|
|
&ver_script.0
|
|
))
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn taptree_builder() {
|
|
let secp = Secp256k1::verification_only();
|
|
let internal_key = UntweakedPublicKey::from_str(
|
|
"93c7378d96518a75448821c4f7c8f4bae7ce60f804d03d1f0628dd5dd0f5de51",
|
|
)
|
|
.unwrap();
|
|
|
|
let builder = TaprootBuilder::new();
|
|
// Create a tree as shown below
|
|
// For example, imagine this tree:
|
|
// A, B , C are at depth 2 and D,E are at 3
|
|
// ....
|
|
// / \
|
|
// /\ /\
|
|
// / \ / \
|
|
// A B C / \
|
|
// D E
|
|
let a = ScriptBuf::from_hex("51").unwrap();
|
|
let b = ScriptBuf::from_hex("52").unwrap();
|
|
let c = ScriptBuf::from_hex("53").unwrap();
|
|
let d = ScriptBuf::from_hex("54").unwrap();
|
|
let e = ScriptBuf::from_hex("55").unwrap();
|
|
let builder = builder.add_leaf(2, a.clone()).unwrap();
|
|
let builder = builder.add_leaf(2, b.clone()).unwrap();
|
|
let builder = builder.add_leaf(2, c.clone()).unwrap();
|
|
let builder = builder.add_leaf(3, d.clone()).unwrap();
|
|
|
|
// Trying to finalize an incomplete tree returns the Err(builder)
|
|
let builder = builder.finalize(&secp, internal_key).unwrap_err();
|
|
let builder = builder.add_leaf(3, e.clone()).unwrap();
|
|
|
|
#[cfg(feature = "serde")]
|
|
{
|
|
let tree = TapTree::try_from(builder.clone()).unwrap();
|
|
// test roundtrip serialization with serde_test
|
|
#[rustfmt::skip]
|
|
assert_tokens(&tree.readable(), &[
|
|
Token::Seq { len: Some(10) },
|
|
Token::U64(2), Token::TupleVariant { name: "TapLeaf", variant: "Script", len: 2}, Token::Str("51"), Token::U8(192), Token::TupleVariantEnd,
|
|
Token::U64(2), Token::TupleVariant { name: "TapLeaf", variant: "Script", len: 2}, Token::Str("52"), Token::U8(192), Token::TupleVariantEnd,
|
|
Token::U64(3), Token::TupleVariant { name: "TapLeaf", variant: "Script", len: 2}, Token::Str("55"), Token::U8(192), Token::TupleVariantEnd,
|
|
Token::U64(3), Token::TupleVariant { name: "TapLeaf", variant: "Script", len: 2}, Token::Str("54"), Token::U8(192), Token::TupleVariantEnd,
|
|
Token::U64(2), Token::TupleVariant { name: "TapLeaf", variant: "Script", len: 2}, Token::Str("53"), Token::U8(192), Token::TupleVariantEnd,
|
|
Token::SeqEnd,
|
|
],);
|
|
|
|
let node_info = TapTree::try_from(builder.clone()).unwrap().into_node_info();
|
|
// test roundtrip serialization with serde_test
|
|
#[rustfmt::skip]
|
|
assert_tokens(&node_info.readable(), &[
|
|
Token::Seq { len: Some(10) },
|
|
Token::U64(2), Token::TupleVariant { name: "TapLeaf", variant: "Script", len: 2}, Token::Str("51"), Token::U8(192), Token::TupleVariantEnd,
|
|
Token::U64(2), Token::TupleVariant { name: "TapLeaf", variant: "Script", len: 2}, Token::Str("52"), Token::U8(192), Token::TupleVariantEnd,
|
|
Token::U64(3), Token::TupleVariant { name: "TapLeaf", variant: "Script", len: 2}, Token::Str("55"), Token::U8(192), Token::TupleVariantEnd,
|
|
Token::U64(3), Token::TupleVariant { name: "TapLeaf", variant: "Script", len: 2}, Token::Str("54"), Token::U8(192), Token::TupleVariantEnd,
|
|
Token::U64(2), Token::TupleVariant { name: "TapLeaf", variant: "Script", len: 2}, Token::Str("53"), Token::U8(192), Token::TupleVariantEnd,
|
|
Token::SeqEnd,
|
|
],);
|
|
}
|
|
|
|
let tree_info = builder.finalize(&secp, internal_key).unwrap();
|
|
let output_key = tree_info.output_key();
|
|
|
|
for script in vec![a, b, c, d, e] {
|
|
let ver_script = (script, LeafVersion::TapScript);
|
|
let ctrl_block = tree_info.control_block(&ver_script).unwrap();
|
|
assert!(ctrl_block.verify_taproot_commitment(
|
|
&secp,
|
|
output_key.to_inner(),
|
|
&ver_script.0
|
|
))
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
#[cfg(feature = "serde")]
|
|
fn test_leaf_version_serde() {
|
|
let leaf_version = LeafVersion::TapScript;
|
|
// use serde_test to test serialization and deserialization
|
|
assert_tokens(&leaf_version, &[Token::U8(192)]);
|
|
|
|
let json = serde_json::to_string(&leaf_version).unwrap();
|
|
let leaf_version2 = serde_json::from_str(&json).unwrap();
|
|
assert_eq!(leaf_version, leaf_version2);
|
|
}
|
|
|
|
#[test]
|
|
#[cfg(feature = "serde")]
|
|
fn test_merkle_branch_serde() {
|
|
let dummy_hash = hex!("03ba2a4dcd914fed29a1c630c7e811271b081a0e2f2f52cf1c197583dfd46c1b");
|
|
let hash1 = TapNodeHash::from_slice(&dummy_hash).unwrap();
|
|
let dummy_hash = hex!("8d79dedc2fa0b55167b5d28c61dbad9ce1191a433f3a1a6c8ee291631b2c94c9");
|
|
let hash2 = TapNodeHash::from_slice(&dummy_hash).unwrap();
|
|
let merkle_branch = TaprootMerkleBranch::from_collection(vec![hash1, hash2]).unwrap();
|
|
// use serde_test to test serialization and deserialization
|
|
serde_test::assert_tokens(
|
|
&merkle_branch.readable(),
|
|
&[
|
|
Token::Seq { len: Some(2) },
|
|
Token::Str("03ba2a4dcd914fed29a1c630c7e811271b081a0e2f2f52cf1c197583dfd46c1b"),
|
|
Token::Str("8d79dedc2fa0b55167b5d28c61dbad9ce1191a433f3a1a6c8ee291631b2c94c9"),
|
|
Token::SeqEnd,
|
|
],
|
|
);
|
|
}
|
|
|
|
#[test]
|
|
fn bip_341_tests() {
|
|
fn process_script_trees(
|
|
v: &serde_json::Value,
|
|
mut builder: TaprootBuilder,
|
|
leaves: &mut Vec<(ScriptBuf, LeafVersion)>,
|
|
depth: u8,
|
|
) -> TaprootBuilder {
|
|
if v.is_null() {
|
|
// nothing to push
|
|
} else if v.is_array() {
|
|
for leaf in v.as_array().unwrap() {
|
|
builder = process_script_trees(leaf, builder, leaves, depth + 1);
|
|
}
|
|
} else {
|
|
let script = ScriptBuf::from_hex(v["script"].as_str().unwrap()).unwrap();
|
|
let ver =
|
|
LeafVersion::from_consensus(v["leafVersion"].as_u64().unwrap() as u8).unwrap();
|
|
leaves.push((script.clone(), ver));
|
|
builder = builder.add_leaf_with_ver(depth, script, ver).unwrap();
|
|
}
|
|
builder
|
|
}
|
|
|
|
let data = bip_341_read_json();
|
|
// Check the version of data
|
|
assert!(data["version"] == 1);
|
|
let secp = &secp256k1::Secp256k1::verification_only();
|
|
|
|
for arr in data["scriptPubKey"].as_array().unwrap() {
|
|
let internal_key =
|
|
XOnlyPublicKey::from_str(arr["given"]["internalPubkey"].as_str().unwrap()).unwrap();
|
|
// process the tree
|
|
let script_tree = &arr["given"]["scriptTree"];
|
|
let mut merkle_root = None;
|
|
if script_tree.is_null() {
|
|
assert!(arr["intermediary"]["merkleRoot"].is_null());
|
|
} else {
|
|
merkle_root = Some(
|
|
TapNodeHash::from_str(arr["intermediary"]["merkleRoot"].as_str().unwrap())
|
|
.unwrap(),
|
|
);
|
|
let leaf_hashes = arr["intermediary"]["leafHashes"].as_array().unwrap();
|
|
let ctrl_blks = arr["expected"]["scriptPathControlBlocks"].as_array().unwrap();
|
|
let mut builder = TaprootBuilder::new();
|
|
let mut leaves = vec![];
|
|
builder = process_script_trees(script_tree, builder, &mut leaves, 0);
|
|
let spend_info = builder.finalize(secp, internal_key).unwrap();
|
|
for (i, script_ver) in leaves.iter().enumerate() {
|
|
let expected_leaf_hash = leaf_hashes[i].as_str().unwrap();
|
|
let expected_ctrl_blk = ControlBlock::decode(
|
|
&Vec::<u8>::from_hex(ctrl_blks[i].as_str().unwrap()).unwrap(),
|
|
)
|
|
.unwrap();
|
|
|
|
let leaf_hash = TapLeafHash::from_script(&script_ver.0, script_ver.1);
|
|
let ctrl_blk = spend_info.control_block(script_ver).unwrap();
|
|
assert_eq!(leaf_hash.to_string(), expected_leaf_hash);
|
|
assert_eq!(ctrl_blk, expected_ctrl_blk);
|
|
}
|
|
}
|
|
let expected_output_key =
|
|
XOnlyPublicKey::from_str(arr["intermediary"]["tweakedPubkey"].as_str().unwrap())
|
|
.unwrap();
|
|
let expected_tweak =
|
|
TapTweakHash::from_str(arr["intermediary"]["tweak"].as_str().unwrap()).unwrap();
|
|
let expected_spk =
|
|
ScriptBuf::from_hex(arr["expected"]["scriptPubKey"].as_str().unwrap()).unwrap();
|
|
let expected_addr =
|
|
Address::from_str(arr["expected"]["bip350Address"].as_str().unwrap())
|
|
.unwrap()
|
|
.assume_checked();
|
|
|
|
let tweak = TapTweakHash::from_key_and_tweak(internal_key, merkle_root);
|
|
let (output_key, _parity) = internal_key.tap_tweak(secp, merkle_root);
|
|
let addr = Address::p2tr(secp, internal_key, merkle_root, Network::Bitcoin);
|
|
let spk = addr.script_pubkey();
|
|
|
|
assert_eq!(expected_output_key, output_key.to_inner());
|
|
assert_eq!(expected_tweak, tweak);
|
|
assert_eq!(expected_addr, addr);
|
|
assert_eq!(expected_spk, spk);
|
|
}
|
|
}
|
|
|
|
fn bip_341_read_json() -> serde_json::Value {
|
|
let json_str = include_str!("../tests/data/bip341_tests.json");
|
|
serde_json::from_str(json_str).expect("JSON was not well-formatted")
|
|
}
|
|
}
|