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-rw-r--r--src/script/descriptor.cpp4
-rw-r--r--src/script/signingprovider.cpp13
-rw-r--r--src/script/signingprovider.h4
-rw-r--r--src/script/standard.cpp57
-rw-r--r--src/script/standard.h34
5 files changed, 105 insertions, 7 deletions
diff --git a/src/script/descriptor.cpp b/src/script/descriptor.cpp
index 51cf8a7d62..84a8b06c5c 100644
--- a/src/script/descriptor.cpp
+++ b/src/script/descriptor.cpp
@@ -843,7 +843,9 @@ protected:
XOnlyPubKey xpk(keys[0]);
if (!xpk.IsFullyValid()) return {};
builder.Finalize(xpk);
- return Vector(GetScriptForDestination(builder.GetOutput()));
+ WitnessV1Taproot output = builder.GetOutput();
+ out.tr_spenddata[output].Merge(builder.GetSpendData());
+ return Vector(GetScriptForDestination(output));
}
bool ToStringSubScriptHelper(const SigningProvider* arg, std::string& ret, bool priv, bool normalized) const override
{
diff --git a/src/script/signingprovider.cpp b/src/script/signingprovider.cpp
index 9781ec32af..b80fbe22ce 100644
--- a/src/script/signingprovider.cpp
+++ b/src/script/signingprovider.cpp
@@ -44,6 +44,11 @@ bool HidingSigningProvider::GetKeyOrigin(const CKeyID& keyid, KeyOriginInfo& inf
return m_provider->GetKeyOrigin(keyid, info);
}
+bool HidingSigningProvider::GetTaprootSpendData(const XOnlyPubKey& output_key, TaprootSpendData& spenddata) const
+{
+ return m_provider->GetTaprootSpendData(output_key, spenddata);
+}
+
bool FlatSigningProvider::GetCScript(const CScriptID& scriptid, CScript& script) const { return LookupHelper(scripts, scriptid, script); }
bool FlatSigningProvider::GetPubKey(const CKeyID& keyid, CPubKey& pubkey) const { return LookupHelper(pubkeys, keyid, pubkey); }
bool FlatSigningProvider::GetKeyOrigin(const CKeyID& keyid, KeyOriginInfo& info) const
@@ -54,6 +59,10 @@ bool FlatSigningProvider::GetKeyOrigin(const CKeyID& keyid, KeyOriginInfo& info)
return ret;
}
bool FlatSigningProvider::GetKey(const CKeyID& keyid, CKey& key) const { return LookupHelper(keys, keyid, key); }
+bool FlatSigningProvider::GetTaprootSpendData(const XOnlyPubKey& output_key, TaprootSpendData& spenddata) const
+{
+ return LookupHelper(tr_spenddata, output_key, spenddata);
+}
FlatSigningProvider Merge(const FlatSigningProvider& a, const FlatSigningProvider& b)
{
@@ -66,6 +75,10 @@ FlatSigningProvider Merge(const FlatSigningProvider& a, const FlatSigningProvide
ret.keys.insert(b.keys.begin(), b.keys.end());
ret.origins = a.origins;
ret.origins.insert(b.origins.begin(), b.origins.end());
+ ret.tr_spenddata = a.tr_spenddata;
+ for (const auto& [output_key, spenddata] : b.tr_spenddata) {
+ ret.tr_spenddata[output_key].Merge(spenddata);
+ }
return ret;
}
diff --git a/src/script/signingprovider.h b/src/script/signingprovider.h
index 76f31d2f6f..939ae10622 100644
--- a/src/script/signingprovider.h
+++ b/src/script/signingprovider.h
@@ -25,6 +25,7 @@ public:
virtual bool GetKey(const CKeyID &address, CKey& key) const { return false; }
virtual bool HaveKey(const CKeyID &address) const { return false; }
virtual bool GetKeyOrigin(const CKeyID& keyid, KeyOriginInfo& info) const { return false; }
+ virtual bool GetTaprootSpendData(const XOnlyPubKey& output_key, TaprootSpendData& spenddata) const { return false; }
};
extern const SigningProvider& DUMMY_SIGNING_PROVIDER;
@@ -42,6 +43,7 @@ public:
bool GetPubKey(const CKeyID& keyid, CPubKey& pubkey) const override;
bool GetKey(const CKeyID& keyid, CKey& key) const override;
bool GetKeyOrigin(const CKeyID& keyid, KeyOriginInfo& info) const override;
+ bool GetTaprootSpendData(const XOnlyPubKey& output_key, TaprootSpendData& spenddata) const override;
};
struct FlatSigningProvider final : public SigningProvider
@@ -50,11 +52,13 @@ struct FlatSigningProvider final : public SigningProvider
std::map<CKeyID, CPubKey> pubkeys;
std::map<CKeyID, std::pair<CPubKey, KeyOriginInfo>> origins;
std::map<CKeyID, CKey> keys;
+ std::map<XOnlyPubKey, TaprootSpendData> tr_spenddata; /** Map from output key to spend data. */
bool GetCScript(const CScriptID& scriptid, CScript& script) const override;
bool GetPubKey(const CKeyID& keyid, CPubKey& pubkey) const override;
bool GetKeyOrigin(const CKeyID& keyid, KeyOriginInfo& info) const override;
bool GetKey(const CKeyID& keyid, CKey& key) const override;
+ bool GetTaprootSpendData(const XOnlyPubKey& output_key, TaprootSpendData& spenddata) const override;
};
FlatSigningProvider Merge(const FlatSigningProvider& a, const FlatSigningProvider& b);
diff --git a/src/script/standard.cpp b/src/script/standard.cpp
index a4b11cc0a9..748f00dda5 100644
--- a/src/script/standard.cpp
+++ b/src/script/standard.cpp
@@ -377,6 +377,16 @@ bool IsValidDestination(const CTxDestination& dest) {
/*static*/ TaprootBuilder::NodeInfo TaprootBuilder::Combine(NodeInfo&& a, NodeInfo&& b)
{
NodeInfo ret;
+ /* Iterate over all tracked leaves in a, add b's hash to their Merkle branch, and move them to ret. */
+ for (auto& leaf : a.leaves) {
+ leaf.merkle_branch.push_back(b.hash);
+ ret.leaves.emplace_back(std::move(leaf));
+ }
+ /* Iterate over all tracked leaves in b, add a's hash to their Merkle branch, and move them to ret. */
+ for (auto& leaf : b.leaves) {
+ leaf.merkle_branch.push_back(a.hash);
+ ret.leaves.emplace_back(std::move(leaf));
+ }
/* Lexicographically sort a and b's hash, and compute parent hash. */
if (a.hash < b.hash) {
ret.hash = (CHashWriter(HASHER_TAPBRANCH) << a.hash << b.hash).GetSHA256();
@@ -386,6 +396,21 @@ bool IsValidDestination(const CTxDestination& dest) {
return ret;
}
+void TaprootSpendData::Merge(TaprootSpendData other)
+{
+ // TODO: figure out how to better deal with conflicting information
+ // being merged.
+ if (internal_key.IsNull() && !other.internal_key.IsNull()) {
+ internal_key = other.internal_key;
+ }
+ if (merkle_root.IsNull() && !other.merkle_root.IsNull()) {
+ merkle_root = other.merkle_root;
+ }
+ for (auto& [key, control_blocks] : other.scripts) {
+ scripts[key].merge(std::move(control_blocks));
+ }
+}
+
void TaprootBuilder::Insert(TaprootBuilder::NodeInfo&& node, int depth)
{
assert(depth >= 0 && (size_t)depth <= TAPROOT_CONTROL_MAX_NODE_COUNT);
@@ -435,13 +460,14 @@ void TaprootBuilder::Insert(TaprootBuilder::NodeInfo&& node, int depth)
return branch.size() == 0 || (branch.size() == 1 && branch[0]);
}
-TaprootBuilder& TaprootBuilder::Add(int depth, const CScript& script, int leaf_version)
+TaprootBuilder& TaprootBuilder::Add(int depth, const CScript& script, int leaf_version, bool track)
{
assert((leaf_version & ~TAPROOT_LEAF_MASK) == 0);
if (!IsValid()) return *this;
- /* Construct NodeInfo object with leaf hash. */
+ /* Construct NodeInfo object with leaf hash and (if track is true) also leaf information. */
NodeInfo node;
node.hash = (CHashWriter{HASHER_TAPLEAF} << uint8_t(leaf_version) << script).GetSHA256();
+ if (track) node.leaves.emplace_back(LeafInfo{script, leaf_version, {}});
/* Insert into the branch. */
Insert(std::move(node), depth);
return *this;
@@ -464,8 +490,33 @@ TaprootBuilder& TaprootBuilder::Finalize(const XOnlyPubKey& internal_key)
m_internal_key = internal_key;
auto ret = m_internal_key.CreateTapTweak(m_branch.size() == 0 ? nullptr : &m_branch[0]->hash);
assert(ret.has_value());
- std::tie(m_output_key, std::ignore) = *ret;
+ std::tie(m_output_key, m_parity) = *ret;
return *this;
}
WitnessV1Taproot TaprootBuilder::GetOutput() { return WitnessV1Taproot{m_output_key}; }
+
+TaprootSpendData TaprootBuilder::GetSpendData() const
+{
+ TaprootSpendData spd;
+ spd.merkle_root = m_branch.size() == 0 ? uint256() : m_branch[0]->hash;
+ spd.internal_key = m_internal_key;
+ if (m_branch.size()) {
+ // If any script paths exist, they have been combined into the root m_branch[0]
+ // by now. Compute the control block for each of its tracked leaves, and put them in
+ // spd.scripts.
+ for (const auto& leaf : m_branch[0]->leaves) {
+ std::vector<unsigned char> control_block;
+ control_block.resize(TAPROOT_CONTROL_BASE_SIZE + TAPROOT_CONTROL_NODE_SIZE * leaf.merkle_branch.size());
+ control_block[0] = leaf.leaf_version | (m_parity ? 1 : 0);
+ std::copy(m_internal_key.begin(), m_internal_key.end(), control_block.begin() + 1);
+ if (leaf.merkle_branch.size()) {
+ std::copy(leaf.merkle_branch[0].begin(),
+ leaf.merkle_branch[0].begin() + TAPROOT_CONTROL_NODE_SIZE * leaf.merkle_branch.size(),
+ control_block.begin() + TAPROOT_CONTROL_BASE_SIZE);
+ }
+ spd.scripts[{leaf.script, leaf.leaf_version}].insert(std::move(control_block));
+ }
+ }
+ return spd;
+}
diff --git a/src/script/standard.h b/src/script/standard.h
index d7ea5cef27..8db17b2779 100644
--- a/src/script/standard.h
+++ b/src/script/standard.h
@@ -11,6 +11,7 @@
#include <uint256.h>
#include <util/hash_type.h>
+#include <map>
#include <string>
#include <variant>
@@ -209,15 +210,38 @@ CScript GetScriptForRawPubKey(const CPubKey& pubkey);
/** Generate a multisig script. */
CScript GetScriptForMultisig(int nRequired, const std::vector<CPubKey>& keys);
+struct TaprootSpendData
+{
+ /** The BIP341 internal key. */
+ XOnlyPubKey internal_key;
+ /** The Merkle root of the script tree (0 if no scripts). */
+ uint256 merkle_root;
+ /** Map from (script, leaf_version) to (sets of) control blocks. */
+ std::map<std::pair<CScript, int>, std::set<std::vector<unsigned char>>> scripts;
+ /** Merge other TaprootSpendData (for the same scriptPubKey) into this. */
+ void Merge(TaprootSpendData other);
+};
+
/** Utility class to construct Taproot outputs from internal key and script tree. */
class TaprootBuilder
{
private:
+ /** Information about a tracked leaf in the Merkle tree. */
+ struct LeafInfo
+ {
+ CScript script; //!< The script.
+ int leaf_version; //!< The leaf version for that script.
+ std::vector<uint256> merkle_branch; //!< The hashing partners above this leaf.
+ };
+
/** Information associated with a node in the Merkle tree. */
struct NodeInfo
{
/** Merkle hash of this node. */
uint256 hash;
+ /** Tracked leaves underneath this node (either from the node itself, or its children).
+ * The merkle_branch field for each is the partners to get to *this* node. */
+ std::vector<LeafInfo> leaves;
};
/** Whether the builder is in a valid state so far. */
bool m_valid = true;
@@ -260,7 +284,8 @@ private:
std::vector<std::optional<NodeInfo>> m_branch;
XOnlyPubKey m_internal_key; //!< The internal key, set when finalizing.
- XOnlyPubKey m_output_key; //!< The output key, computed when finalizing. */
+ XOnlyPubKey m_output_key; //!< The output key, computed when finalizing.
+ bool m_parity; //!< The tweak parity, computed when finalizing.
/** Combine information about a parent Merkle tree node from its child nodes. */
static NodeInfo Combine(NodeInfo&& a, NodeInfo&& b);
@@ -269,8 +294,9 @@ private:
public:
/** Add a new script at a certain depth in the tree. Add() operations must be called
- * in depth-first traversal order of binary tree. */
- TaprootBuilder& Add(int depth, const CScript& script, int leaf_version);
+ * in depth-first traversal order of binary tree. If track is true, it will be included in
+ * the GetSpendData() output. */
+ TaprootBuilder& Add(int depth, const CScript& script, int leaf_version, bool track = true);
/** Like Add(), but for a Merkle node with a given hash to the tree. */
TaprootBuilder& AddOmitted(int depth, const uint256& hash);
/** Finalize the construction. Can only be called when IsComplete() is true.
@@ -285,6 +311,8 @@ public:
WitnessV1Taproot GetOutput();
/** Check if a list of depths is legal (will lead to IsComplete()). */
static bool ValidDepths(const std::vector<int>& depths);
+ /** Compute spending data (after Finalize()). */
+ TaprootSpendData GetSpendData() const;
};
#endif // BITCOIN_SCRIPT_STANDARD_H
generated by cgit v1.2.3 (git 2.26.2) at 2024-08-20 08:07:38 +0000