// SPDX-License-Identifier: CC0-1.0
//! Bitcoin Taproot.
//!
//! This module provides support for taproot tagged hashes.
//!
use crate::prelude::*;
use crate::io;
use secp256k1::{self, Secp256k1, Scalar};
use core::convert::TryFrom;
use core::fmt;
use core::cmp::Reverse;
use crate::hashes::{sha256, sha256t_hash_newtype, Hash, HashEngine};
use crate::schnorr::{TweakedPublicKey, UntweakedPublicKey, TapTweak};
use crate::util::key::XOnlyPublicKey;
use crate::Script;
use crate::internal_macros::write_err;
use crate::consensus::Encodable;
/// The SHA-256 midstate value for the TapLeaf hash.
const MIDSTATE_TAPLEAF: [u8; 32] = [
156, 224, 228, 230, 124, 17, 108, 57, 56, 179, 202, 242, 195, 15, 80, 137, 211, 243, 147, 108,
71, 99, 110, 96, 125, 179, 62, 234, 221, 198, 240, 201,
];
// 9ce0e4e67c116c3938b3caf2c30f5089d3f3936c47636e607db33eeaddc6f0c9
/// The SHA-256 midstate value for the TapBranch hash.
const MIDSTATE_TAPBRANCH: [u8; 32] = [
35, 168, 101, 169, 184, 164, 13, 167, 151, 124, 30, 4, 196, 158, 36, 111, 181, 190, 19, 118,
157, 36, 201, 183, 181, 131, 181, 212, 168, 210, 38, 210,
];
// 23a865a9b8a40da7977c1e04c49e246fb5be13769d24c9b7b583b5d4a8d226d2
/// The SHA-256 midstate value for the TapTweak hash.
const MIDSTATE_TAPTWEAK: [u8; 32] = [
209, 41, 162, 243, 112, 28, 101, 93, 101, 131, 182, 195, 185, 65, 151, 39, 149, 244, 226, 50,
148, 253, 84, 244, 162, 174, 141, 133, 71, 202, 89, 11,
];
// d129a2f3701c655d6583b6c3b941972795f4e23294fd54f4a2ae8d8547ca590b
/// The SHA-256 midstate value for the [`TapSighashHash`].
const MIDSTATE_TAPSIGHASH: [u8; 32] = [
245, 4, 164, 37, 215, 248, 120, 59, 19, 99, 134, 138, 227, 229, 86, 88, 110, 238, 148, 93, 188,
120, 136, 221, 2, 166, 226, 195, 24, 115, 254, 159,
];
// f504a425d7f8783b1363868ae3e556586eee945dbc7888dd02a6e2c31873fe9f
// Taproot test vectors from BIP-341 state the hashes without any reversing
sha256t_hash_newtype!(TapLeafHash, TapLeafTag, MIDSTATE_TAPLEAF, 64,
doc="Taproot-tagged hash for tapscript Merkle tree leafs", false
);
sha256t_hash_newtype!(TapBranchHash, TapBranchTag, MIDSTATE_TAPBRANCH, 64,
doc="Taproot-tagged hash for tapscript Merkle tree branches", false
);
sha256t_hash_newtype!(TapTweakHash, TapTweakTag, MIDSTATE_TAPTWEAK, 64,
doc="Taproot-tagged hash for public key tweaks", false
);
sha256t_hash_newtype!(TapSighashHash, TapSighashTag, MIDSTATE_TAPSIGHASH, 64,
doc="Taproot-tagged hash for the taproot signature hash", false
);
impl secp256k1::ThirtyTwoByteHash for TapSighashHash {
fn into_32(self) -> [u8; 32] {
self.into_inner()
}
}
impl TapTweakHash {
/// Creates a new BIP341 [`TapTweakHash`] from key and tweak. Produces `H_taptweak(P||R)` where
/// `P` is the internal key and `R` is the merkle root.
pub fn from_key_and_tweak(
internal_key: UntweakedPublicKey,
merkle_root: Option<TapBranchHash>,
) -> TapTweakHash {
let mut eng = TapTweakHash::engine();
// always hash the key
eng.input(&internal_key.serialize());
if let Some(h) = merkle_root {
eng.input(&h);
} else {
// nothing to hash
}
TapTweakHash::from_engine(eng)
}
/// Converts a `TapTweakHash` into a `Scalar` ready for use with key tweaking API.
pub fn to_scalar(self) -> Scalar {
// This is statistically extremely unlikely to panic.
Scalar::from_be_bytes(self.into_inner()).expect("hash value greater than curve order")
}
}
impl TapLeafHash {
/// Computes the leaf hash from components.
pub fn from_script(script: &Script, ver: LeafVersion) -> TapLeafHash {
let mut eng = TapLeafHash::engine();
ver.to_consensus()
.consensus_encode(&mut eng)
.expect("engines don't error");
script
.consensus_encode(&mut eng)
.expect("engines don't error");
TapLeafHash::from_engine(eng)
}
}
impl TapBranchHash {
/// Computes branch hash given two hashes of the nodes underneath it.
pub fn from_node_hashes(a: sha256::Hash, b: sha256::Hash) -> TapBranchHash {
let mut eng = TapBranchHash::engine();
if a < b {
eng.input(&a);
eng.input(&b);
} else {
eng.input(&b);
eng.input(&a);
};
TapBranchHash::from_engine(eng)
}
}
/// Maximum depth of a taproot tree script spend path.
// https://github.com/bitcoin/bitcoin/blob/e826b22da252e0599c61d21c98ff89f366b3120f/src/script/interpreter.h#L229
pub const TAPROOT_CONTROL_MAX_NODE_COUNT: usize = 128;
/// Size of a taproot control node.
// https://github.com/bitcoin/bitcoin/blob/e826b22da252e0599c61d21c98ff89f366b3120f/src/script/interpreter.h#L228
pub const TAPROOT_CONTROL_NODE_SIZE: usize = 32;
/// Tapleaf mask for getting the leaf version from first byte of control block.
// https://github.com/bitcoin/bitcoin/blob/e826b22da252e0599c61d21c98ff89f366b3120f/src/script/interpreter.h#L225
pub const TAPROOT_LEAF_MASK: u8 = 0xfe;
/// Tapscript leaf version.
// https://github.com/bitcoin/bitcoin/blob/e826b22da252e0599c61d21c98ff89f366b3120f/src/script/interpreter.h#L226
pub const TAPROOT_LEAF_TAPSCRIPT: u8 = 0xc0;
/// Taproot annex prefix.
pub const TAPROOT_ANNEX_PREFIX: u8 = 0x50;
/// Tapscript control base size.
// https://github.com/bitcoin/bitcoin/blob/e826b22da252e0599c61d21c98ff89f366b3120f/src/script/interpreter.h#L227
pub const TAPROOT_CONTROL_BASE_SIZE: usize = 33;
/// Tapscript control max size.
// https://github.com/bitcoin/bitcoin/blob/e826b22da252e0599c61d21c98ff89f366b3120f/src/script/interpreter.h#L230
pub const TAPROOT_CONTROL_MAX_SIZE: usize =
TAPROOT_CONTROL_BASE_SIZE + TAPROOT_CONTROL_NODE_SIZE * TAPROOT_CONTROL_MAX_NODE_COUNT;
// type alias for versioned tap script corresponding merkle proof
type ScriptMerkleProofMap = BTreeMap<(Script, LeafVersion), BTreeSet<TaprootMerkleBranch>>;
/// Represents taproot spending information.
///
/// Taproot output corresponds to a combination of a single public key condition (known as the
/// internal key), and zero or more general conditions encoded in scripts organized in the form of a
/// binary tree.
///
/// Taproot can be spent by either:
/// - Spending using the key path i.e., with secret key corresponding to the tweaked `output_key`.
/// - By satisfying any of the scripts in the script spend path. Each script can be satisfied by
/// providing a witness stack consisting of the script's inputs, plus the script itself and the
/// control block.
///
/// If one or more of the spending conditions consist of just a single key (after aggregation), the
/// most likely key should be made the internal key.
/// See [BIP341](https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki) for more details on
/// choosing internal keys for a taproot application.
///
/// Note: This library currently does not support
/// [annex](https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki#cite_note-5).
#[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 TaprootSpendInfo {
/// The BIP341 internal key.
internal_key: UntweakedPublicKey,
/// The merkle root of the script tree (None if there are no scripts).
merkle_root: Option<TapBranchHash>,
/// The sign final output pubkey as per BIP 341.
output_key_parity: secp256k1::Parity,
/// The tweaked output key.
output_key: TweakedPublicKey,
/// Map from (script, leaf_version) to (sets of) [`TaprootMerkleBranch`]. More than one control
/// block for a given script is only possible if it appears in multiple branches of the tree. In
/// all cases, keeping one should be enough for spending funds, but we keep all of the paths so
/// that a full tree can be constructed again from spending data if required.
script_map: ScriptMerkleProofMap,
}
impl TaprootSpendInfo {
/// Creates a new [`TaprootSpendInfo`] from a list of scripts (with default script version) and
/// weights of satisfaction for that script.
///
/// See [`TaprootBuilder::with_huffman_tree`] for more detailed documentation.
pub fn with_huffman_tree<C, I>(
secp: &Secp256k1<C>,
internal_key: UntweakedPublicKey,
script_weights: I,
) -> Result<Self, TaprootBuilderError>
where
I: IntoIterator<Item=(u32, Script)>,
C: secp256k1::Verification,
{
let builder = TaprootBuilder::with_huffman_tree(script_weights)?;
Ok(builder.finalize(secp, internal_key).expect("Huffman Tree is always complete"))
}
/// Creates a new key spend with `internal_key` and `merkle_root`. Provide [`None`] for
/// the `merkle_root` if there is no script path.
///
/// *Note*: As per BIP341
///
/// When the merkle root is [`None`], the output key commits to an unspendable script path
/// instead of having no script path. This is achieved by computing the output key point as
/// `Q = P + int(hashTapTweak(bytes(P)))G`. See also [`TaprootSpendInfo::tap_tweak`].
///
/// Refer to BIP 341 footnote ('Why should the output key always have a taproot commitment, even
/// if there is no script path?') for more details.
pub fn new_key_spend<C: secp256k1::Verification>(
secp: &Secp256k1<C>,
internal_key: UntweakedPublicKey,
merkle_root: Option<TapBranchHash>,
) -> Self {
let (output_key, parity) = internal_key.tap_tweak(secp, merkle_root);
Self {
internal_key,
merkle_root,
output_key_parity: parity,
output_key,
script_map: BTreeMap::new(),
}
}
/// Returns the `TapTweakHash` for this [`TaprootSpendInfo`] i.e., the tweak using `internal_key`
/// and `merkle_root`.
pub fn tap_tweak(&self) -> TapTweakHash {
TapTweakHash::from_key_and_tweak(self.internal_key, self.merkle_root)
}
/// Returns the internal key for this [`TaprootSpendInfo`].
pub fn internal_key(&self) -> UntweakedPublicKey {
self.internal_key
}
/// Returns the merkle root for this [`TaprootSpendInfo`].
pub fn merkle_root(&self) -> Option<TapBranchHash> {
self.merkle_root
}
/// Returns the output key (the key used in script pubkey) for this [`TaprootSpendInfo`].
pub fn output_key(&self) -> TweakedPublicKey {
self.output_key
}
/// Returns the parity of the output key. See also [`TaprootSpendInfo::output_key`].
pub fn output_key_parity(&self) -> secp256k1::Parity {
self.output_key_parity
}
/// Computes the [`TaprootSpendInfo`] from `internal_key` and `node`.
///
/// This is useful when you want to manually build a taproot tree without using
/// [`TaprootBuilder`].
pub fn from_node_info<C: secp256k1::Verification>(
secp: &Secp256k1<C>,
internal_key: UntweakedPublicKey,
node: NodeInfo,
) -> TaprootSpendInfo {
// Create as if it is a key spend path with the given merkle root
let root_hash = Some(TapBranchHash::from_inner(node.hash.into_inner()));
let mut info = TaprootSpendInfo::new_key_spend(secp, internal_key, root_hash);
for leaves in node.leaves {
let key = (leaves.script, leaves.ver);
let value = leaves.merkle_branch;
if let Some(set) = info.script_map.get_mut(&key) {
set.insert(value);
continue; // NLL fix
}
let mut set = BTreeSet::new();
set.insert(value);
info.script_map.insert(key, set);
}
info
}
/// Returns the internal script map.
pub fn as_script_map(&self) -> &ScriptMerkleProofMap {
&self.script_map
}
/// Constructs a [`ControlBlock`] for particular script with the given version.
///
/// # Returns
///
/// - If there are multiple control blocks possible, returns the shortest one.
/// - If the script is not contained in the [`TaprootSpendInfo`], returns `None`.
pub fn control_block(&self, script_ver: &(Script, LeafVersion)) -> Option<ControlBlock> {
let merkle_branch_set = self.script_map.get(script_ver)?;
// Choose the smallest one amongst the multiple script maps
let smallest = merkle_branch_set
.iter()
.min_by(|x, y| x.0.len().cmp(&y.0.len()))
.expect("Invariant: Script map key must contain non-empty set value");
Some(ControlBlock {
internal_key: self.internal_key,
output_key_parity: self.output_key_parity,
leaf_version: script_ver.1,
merkle_branch: smallest.clone(),
})
}
}
/// Builder for building taproot iteratively. Users can specify tap leaf or omitted/hidden branches
/// in a depth-first search (DFS) walk order to construct this tree.
///
/// See Wikipedia for more details on [DFS](https://en.wikipedia.org/wiki/Depth-first_search).
// Similar to Taproot Builder in bitcoin core.
#[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 TaprootBuilder {
// The following doc-comment is from bitcoin core, but modified for Rust. It describes the
// current state of the builder for a given tree.
//
// For each level in the tree, one NodeInfo object may be present. Branch at index 0 is
// information about the root; further values are for deeper subtrees being explored.
//
// During the construction of Taptree, for every right branch taken to reach the position we're
// currently working on, there will be a `(Some(_))` entry in branch corresponding to the left
// branch at that level.
//
// For example, imagine this tree: - N0 -
// / \
// N1 N2
// / \ / \
// A B C N3
// / \
// D E
//
// Initially, branch is empty. After processing leaf A, it would become {None, None, A}. When
// processing leaf B, an entry at level 2 already exists, and it would thus be combined with it
// to produce a level 1 entry, resulting in {None, N1}. Adding C and D takes us to {None, N1, C}
// and {None, N1, C, D} respectively. When E is processed, it is combined with D, and then C,
// and then N1, to produce the root, resulting in {N0}.
//
// This structure allows processing with just O(log n) overhead if the leaves are computed on
// the fly.
//
// As an invariant, there can never be None entries at the end. There can also not be more than
// 128 entries (as that would mean more than 128 levels in the tree). The depth of newly added
// entries will always be at least equal to the current size of branch (otherwise it does not
// correspond to a depth-first traversal of a tree). A branch is only empty if no entries have
// ever be processed. A branch having length 1 corresponds to being done.
branch: Vec<Option<NodeInfo>>,
}
impl TaprootBuilder {
/// Creates a new instance of [`TaprootBuilder`].
pub fn new() -> Self {
TaprootBuilder { branch: vec![] }
}
/// Creates a new [`TaprootSpendInfo`] from a list of scripts (with default script version) and
/// weights of satisfaction for that script.
///
/// The weights represent the probability of each branch being taken. If probabilities/weights
/// for each condition are known, constructing the tree as a Huffman Tree is the optimal way to
/// minimize average case satisfaction cost. This function takes as input an iterator of
/// `tuple(u32, &Script)` where `u32` represents the satisfaction weights of the branch. For
/// example, [(3, S1), (2, S2), (5, S3)] would construct a [`TapTree`] that has optimal
/// satisfaction weight when probability for S1 is 30%, S2 is 20% and S3 is 50%.
///
/// # Errors:
///
/// - When the optimal Huffman Tree has a depth more than 128.
/// - If the provided list of script weights is empty.
///
/// # Edge Cases:
///
/// If the script weight calculations overflow, a sub-optimal tree may be generated. This should
/// not happen unless you are dealing with billions of branches with weights close to 2^32.
///
/// [`TapTree`]: crate::util::psbt::TapTree
pub fn with_huffman_tree<I>(
script_weights: I,
) -> Result<Self, TaprootBuilderError>
where
I: IntoIterator<Item=(u32, Script)>,
{
let mut node_weights = BinaryHeap::<(Reverse<u32>, NodeInfo)>::new();
for (p, leaf) in script_weights {
node_weights.push((Reverse(p), NodeInfo::new_leaf_with_ver(leaf, LeafVersion::TapScript)));
}
if node_weights.is_empty() {
return Err(TaprootBuilderError::EmptyTree);
}
while node_weights.len() > 1 {
// Combine the last two elements and insert a new node
let (p1, s1) = node_weights.pop().expect("len must be at least two");
let (p2, s2) = node_weights.pop().expect("len must be at least two");
// Insert the sum of first two in the tree as a new node
// 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: Script,
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: Script) -> 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: sha256::Hash) -> 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()
}
/// 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).into_iter().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()
}
}
/// Represents the node information in taproot tree.
///
/// 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, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
#[cfg_attr(feature = "serde", serde(crate = "actual_serde"))]
pub struct NodeInfo {
/// Merkle hash for this node.
pub(crate) hash: sha256::Hash,
/// Information about leaves inside this node.
pub(crate) leaves: Vec<ScriptLeaf>,
/// Tracks information on hidden nodes below this node.
pub(crate) has_hidden_nodes: bool,
}
impl NodeInfo {
/// Creates a new [`NodeInfo`] with omitted/hidden info.
pub fn new_hidden_node(hash: sha256::Hash) -> Self {
Self {
hash,
leaves: vec![],
has_hidden_nodes: true
}
}
/// Creates a new leaf [`NodeInfo`] with given [`Script`] and [`LeafVersion`].
pub fn new_leaf_with_ver(script: Script, ver: LeafVersion) -> Self {
let leaf = ScriptLeaf::new(script, ver);
Self {
hash: sha256::Hash::from_inner(leaf.leaf_hash().into_inner()),
leaves: vec![leaf],
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());
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);
}
let hash = TapBranchHash::from_node_hashes(a.hash, b.hash);
Ok(Self {
hash: sha256::Hash::from_inner(hash.into_inner()),
leaves: all_leaves,
has_hidden_nodes: a.has_hidden_nodes || b.has_hidden_nodes
})
}
}
/// Store information about taproot leaf node.
#[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 ScriptLeaf {
/// The underlying script.
script: Script,
/// The leaf version.
ver: LeafVersion,
/// The merkle proof (hashing partners) to get this node.
merkle_branch: TaprootMerkleBranch,
}
impl ScriptLeaf {
/// Creates an new [`ScriptLeaf`] from `script` and `ver` and no merkle branch.
fn new(script: Script, ver: LeafVersion) -> Self {
Self {
script,
ver,
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`].
#[inline]
pub fn leaf_hash(&self) -> TapLeafHash {
TapLeafHash::from_script(&self.script, self.ver)
}
/// Returns reference to the leaf script.
#[inline]
pub fn script(&self) -> &Script {
&self.script
}
/// Returns leaf version of the script.
#[inline]
pub fn leaf_version(&self) -> LeafVersion {
self.ver
}
/// 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
}
}
/// The merkle proof for inclusion of a tree in a taptree hash.
// The type of hash is `sha256::Hash` because the vector might contain both `TapBranchHash` and
// `TapLeafHash`.
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
#[cfg_attr(feature = "serde", serde(crate = "actual_serde"))]
pub struct TaprootMerkleBranch(Vec<sha256::Hash>);
impl TaprootMerkleBranch {
/// Returns a reference to the inner vector of hashes.
pub fn as_inner(&self) -> &[sha256::Hash] {
&self.0
}
/// Creates a merkle proof from raw data representing a list of hashes.
pub fn from_slice(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| {
sha256::Hash::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<[sha256::Hash]> + Into<Vec<sha256::Hash>>>(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)?;
}
Ok(self.0.len() * sha256::Hash::LEN)
}
/// Serializes `self` as bytes.
pub fn serialize(&self) -> Vec<u8> {
self.0.iter().flat_map(|e| e.as_inner()).copied().collect::<Vec<u8>>()
}
/// Appends elements to proof.
fn push(&mut self, h: sha256::Hash) -> Result<(), TaprootBuilderError> {
if self.0.len() >= TAPROOT_CONTROL_MAX_NODE_COUNT {
Err(TaprootBuilderError::InvalidMerkleTreeDepth(self.0.len()))
} else {
self.0.push(h);
Ok(())
}
}
/// Creates a merkle proof from list of hashes.
///
/// # Errors
///
/// If inner proof length is more than [`TAPROOT_CONTROL_MAX_NODE_COUNT`] (128).
#[deprecated(since = "0.29.0", note = "use try_from instead")]
pub fn from_inner(inner: Vec<sha256::Hash>) -> Result<Self, TaprootError> {
Self::try_from(inner)
}
/// Returns the inner list of hashes.
pub fn into_inner(self) -> Vec<sha256::Hash> {
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!(&[sha256::Hash]);
impl_try_from!(Vec<sha256::Hash>);
impl_try_from!(Box<[sha256::Hash]>);
/// 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 {
/// Constructs a `ControlBlock` from slice. 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 from_slice(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::from_slice(&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 leaf_hash = TapLeafHash::from_script(script, self.leaf_version);
let mut curr_hash = TapBranchHash::from_inner(leaf_hash.into_inner());
// Verify the proof
for elem in self.merkle_branch.as_inner() {
// Recalculate the curr hash as parent hash
curr_hash = TapBranchHash::from_node_hashes(
sha256::Hash::from_inner(curr_hash.into_inner()),
*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")]
#[cfg_attr(docsrs, doc(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")]
#[cfg_attr(docsrs, doc(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_u8<E>(self, value: u8) -> Result<Self::Value, E>
where
E: serde::de::Error,
{
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")]
#[cfg_attr(docsrs, doc(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")]
#[cfg_attr(docsrs, doc(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 crate::{Address, Network};
use crate::schnorr::TapTweak;
use super::*;
use crate::hashes::hex::{FromHex, ToHex};
use crate::hashes::sha256t::Tag;
use crate::hashes::{sha256, Hash, HashEngine};
use secp256k1::{VerifyOnly, XOnlyPublicKey};
use core::str::FromStr;
extern crate serde_json;
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[..]);
engine.input(&tag_hash[..]);
engine
}
#[test]
fn test_midstates() {
// check midstate against hard-coded values
assert_eq!(MIDSTATE_TAPLEAF, tag_engine("TapLeaf").midstate().into_inner());
assert_eq!(MIDSTATE_TAPBRANCH, tag_engine("TapBranch").midstate().into_inner());
assert_eq!(MIDSTATE_TAPTWEAK, tag_engine("TapTweak").midstate().into_inner());
assert_eq!(MIDSTATE_TAPSIGHASH, tag_engine("TapSighash").midstate().into_inner());
// 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(&[]);
sha256::Hash::from_engine(e).into_inner()
}
assert_eq!(empty_hash("TapLeaf"), TapLeafHash::hash(&[]).into_inner());
assert_eq!(empty_hash("TapBranch"), TapBranchHash::hash(&[]).into_inner());
assert_eq!(empty_hash("TapTweak"), TapTweakHash::hash(&[]).into_inner());
assert_eq!(empty_hash("TapSighash"), TapSighashHash::hash(&[]).into_inner());
}
#[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_hex(),
"5212c288a377d1f8164962a5a13429f9ba6a7b84e59776a52c6637df2106facb"
);
assert_eq!(
TapBranchHash::from_engine(TapBranchTag::engine()).to_hex(),
"53c373ec4d6f3c53c1f5fb2ff506dcefe1a0ed74874f93fa93c8214cbe9ffddf"
);
assert_eq!(
TapTweakHash::from_engine(TapTweakTag::engine()).to_hex(),
"8aa4229474ab0100b2d6f0687f031d1fc9d8eef92a042ad97d279bff456b15e4"
);
assert_eq!(
TapSighashHash::from_engine(TapSighashTag::engine()).to_hex(),
"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_hex(),
"ed1382037800c9dd938dd8854f1a8863bcdeb6705069b4b56a66ec22519d5829"
);
assert_eq!(
TapBranchHash::hash(&[0]).to_hex(),
"92534b1960c7e6245af7d5fda2588db04aa6d646abc2b588dab2b69e5645eb1d"
);
assert_eq!(
TapTweakHash::hash(&[0]).to_hex(),
"cd8737b5e6047fc3f16f03e8b9959e3440e1bdf6dd02f7bb899c352ad490ea1e"
);
assert_eq!(
TapSighashHash::hash(&[0]).to_hex(),
"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 = Script::from_hex(script_hex).unwrap();
let control_block = ControlBlock::from_slice(&Vec::<u8>::from_hex(control_block_hex).unwrap()).unwrap();
assert_eq!(control_block_hex, control_block.serialize().to_hex());
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, Script::from_hex("51").unwrap()), // semantics of script don't matter for this test
(20, Script::from_hex("52").unwrap()),
(20, Script::from_hex("53").unwrap()),
(30, Script::from_hex("54").unwrap()),
(19, Script::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(&(Script::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 = Script::from_hex("51").unwrap();
let b = Script::from_hex("52").unwrap();
let c = Script::from_hex("53").unwrap();
let d = Script::from_hex("54").unwrap();
let e = Script::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();
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]
fn bip_341_tests() {
fn process_script_trees(
v: &serde_json::Value,
mut builder: TaprootBuilder,
leaves: &mut Vec<(Script, 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 = Script::from_str(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(TapBranchHash::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::from_slice(&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_hex(), 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 = Script::from_str(arr["expected"]["scriptPubKey"].as_str().unwrap()).unwrap();
let expected_addr = Address::from_str(arr["expected"]["bip350Address"].as_str().unwrap()).unwrap();
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!("../../test_data/bip341_tests.json");
serde_json::from_str(json_str).expect("JSON was not well-formatted")
}
}