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-rw-r--r--src/script/descriptor.cpp4
-rw-r--r--src/script/interpreter.cpp14
-rw-r--r--src/script/interpreter.h5
-rw-r--r--src/script/sign.cpp195
-rw-r--r--src/script/sign.h9
-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.h46
9 files changed, 322 insertions, 25 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/interpreter.cpp b/src/script/interpreter.cpp
index 3c3c3ac1a8..2dd173ee20 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -1420,7 +1420,7 @@ uint256 GetSpentScriptsSHA256(const std::vector<CTxOut>& outputs_spent)
} // namespace
template <class T>
-void PrecomputedTransactionData::Init(const T& txTo, std::vector<CTxOut>&& spent_outputs)
+void PrecomputedTransactionData::Init(const T& txTo, std::vector<CTxOut>&& spent_outputs, bool force)
{
assert(!m_spent_outputs_ready);
@@ -1431,9 +1431,9 @@ void PrecomputedTransactionData::Init(const T& txTo, std::vector<CTxOut>&& spent
}
// Determine which precomputation-impacting features this transaction uses.
- bool uses_bip143_segwit = false;
- bool uses_bip341_taproot = false;
- for (size_t inpos = 0; inpos < txTo.vin.size(); ++inpos) {
+ bool uses_bip143_segwit = force;
+ bool uses_bip341_taproot = force;
+ for (size_t inpos = 0; inpos < txTo.vin.size() && !(uses_bip143_segwit && uses_bip341_taproot); ++inpos) {
if (!txTo.vin[inpos].scriptWitness.IsNull()) {
if (m_spent_outputs_ready && m_spent_outputs[inpos].scriptPubKey.size() == 2 + WITNESS_V1_TAPROOT_SIZE &&
m_spent_outputs[inpos].scriptPubKey[0] == OP_1) {
@@ -1478,8 +1478,8 @@ PrecomputedTransactionData::PrecomputedTransactionData(const T& txTo)
}
// explicit instantiation
-template void PrecomputedTransactionData::Init(const CTransaction& txTo, std::vector<CTxOut>&& spent_outputs);
-template void PrecomputedTransactionData::Init(const CMutableTransaction& txTo, std::vector<CTxOut>&& spent_outputs);
+template void PrecomputedTransactionData::Init(const CTransaction& txTo, std::vector<CTxOut>&& spent_outputs, bool force);
+template void PrecomputedTransactionData::Init(const CMutableTransaction& txTo, std::vector<CTxOut>&& spent_outputs, bool force);
template PrecomputedTransactionData::PrecomputedTransactionData(const CTransaction& txTo);
template PrecomputedTransactionData::PrecomputedTransactionData(const CMutableTransaction& txTo);
@@ -1711,7 +1711,7 @@ bool GenericTransactionSignatureChecker<T>::CheckSchnorrSignature(Span<const uns
if (hashtype == SIGHASH_DEFAULT) return set_error(serror, SCRIPT_ERR_SCHNORR_SIG_HASHTYPE);
}
uint256 sighash;
- assert(this->txdata);
+ if (!this->txdata) return HandleMissingData(m_mdb);
if (!SignatureHashSchnorr(sighash, execdata, *txTo, nIn, hashtype, sigversion, *this->txdata, m_mdb)) {
return set_error(serror, SCRIPT_ERR_SCHNORR_SIG_HASHTYPE);
}
diff --git a/src/script/interpreter.h b/src/script/interpreter.h
index fa4ee83e04..ced5c28bc1 100644
--- a/src/script/interpreter.h
+++ b/src/script/interpreter.h
@@ -168,7 +168,7 @@ struct PrecomputedTransactionData
PrecomputedTransactionData() = default;
template <class T>
- void Init(const T& tx, std::vector<CTxOut>&& spent_outputs);
+ void Init(const T& tx, std::vector<CTxOut>&& spent_outputs, bool force = false);
template <class T>
explicit PrecomputedTransactionData(const T& tx);
@@ -260,6 +260,9 @@ enum class MissingDataBehavior
FAIL, //!< Just act as if the signature was invalid
};
+template<typename T>
+bool SignatureHashSchnorr(uint256& hash_out, const ScriptExecutionData& execdata, const T& tx_to, uint32_t in_pos, uint8_t hash_type, SigVersion sigversion, const PrecomputedTransactionData& cache, MissingDataBehavior mdb);
+
template <class T>
class GenericTransactionSignatureChecker : public BaseSignatureChecker
{
diff --git a/src/script/sign.cpp b/src/script/sign.cpp
index da0092f9e3..65276f641f 100644
--- a/src/script/sign.cpp
+++ b/src/script/sign.cpp
@@ -11,13 +11,28 @@
#include <script/signingprovider.h>
#include <script/standard.h>
#include <uint256.h>
+#include <util/vector.h>
typedef std::vector<unsigned char> valtype;
-MutableTransactionSignatureCreator::MutableTransactionSignatureCreator(const CMutableTransaction* txToIn, unsigned int nInIn, const CAmount& amountIn, int nHashTypeIn) : txTo(txToIn), nIn(nInIn), nHashType(nHashTypeIn), amount(amountIn), checker(txTo, nIn, amountIn, MissingDataBehavior::FAIL) {}
+MutableTransactionSignatureCreator::MutableTransactionSignatureCreator(const CMutableTransaction* txToIn, unsigned int nInIn, const CAmount& amountIn, int nHashTypeIn)
+ : txTo(txToIn), nIn(nInIn), nHashType(nHashTypeIn), amount(amountIn), checker(txTo, nIn, amountIn, MissingDataBehavior::FAIL),
+ m_txdata(nullptr)
+{
+}
+
+MutableTransactionSignatureCreator::MutableTransactionSignatureCreator(const CMutableTransaction* txToIn, unsigned int nInIn, const CAmount& amountIn, const PrecomputedTransactionData* txdata, int nHashTypeIn)
+ : txTo(txToIn), nIn(nInIn), nHashType(nHashTypeIn), amount(amountIn),
+ checker(txdata ? MutableTransactionSignatureChecker(txTo, nIn, amount, *txdata, MissingDataBehavior::FAIL) :
+ MutableTransactionSignatureChecker(txTo, nIn, amount, MissingDataBehavior::FAIL)),
+ m_txdata(txdata)
+{
+}
bool MutableTransactionSignatureCreator::CreateSig(const SigningProvider& provider, std::vector<unsigned char>& vchSig, const CKeyID& address, const CScript& scriptCode, SigVersion sigversion) const
{
+ assert(sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0);
+
CKey key;
if (!provider.GetKey(address, key))
return false;
@@ -26,13 +41,61 @@ bool MutableTransactionSignatureCreator::CreateSig(const SigningProvider& provid
if (sigversion == SigVersion::WITNESS_V0 && !key.IsCompressed())
return false;
- // Signing for witness scripts needs the amount.
- if (sigversion == SigVersion::WITNESS_V0 && amount < 0) return false;
+ // Signing without known amount does not work in witness scripts.
+ if (sigversion == SigVersion::WITNESS_V0 && !MoneyRange(amount)) return false;
+
+ // BASE/WITNESS_V0 signatures don't support explicit SIGHASH_DEFAULT, use SIGHASH_ALL instead.
+ const int hashtype = nHashType == SIGHASH_DEFAULT ? SIGHASH_ALL : nHashType;
- uint256 hash = SignatureHash(scriptCode, *txTo, nIn, nHashType, amount, sigversion);
+ uint256 hash = SignatureHash(scriptCode, *txTo, nIn, hashtype, amount, sigversion, m_txdata);
if (!key.Sign(hash, vchSig))
return false;
- vchSig.push_back((unsigned char)nHashType);
+ vchSig.push_back((unsigned char)hashtype);
+ return true;
+}
+
+bool MutableTransactionSignatureCreator::CreateSchnorrSig(const SigningProvider& provider, std::vector<unsigned char>& sig, const XOnlyPubKey& pubkey, const uint256* leaf_hash, const uint256* merkle_root, SigVersion sigversion) const
+{
+ assert(sigversion == SigVersion::TAPROOT || sigversion == SigVersion::TAPSCRIPT);
+
+ CKey key;
+ {
+ // For now, use the old full pubkey-based key derivation logic. As it indexed by
+ // Hash160(full pubkey), we need to try both a version prefixed with 0x02, and one
+ // with 0x03.
+ unsigned char b[33] = {0x02};
+ std::copy(pubkey.begin(), pubkey.end(), b + 1);
+ CPubKey fullpubkey;
+ fullpubkey.Set(b, b + 33);
+ CKeyID keyid = fullpubkey.GetID();
+ if (!provider.GetKey(keyid, key)) {
+ b[0] = 0x03;
+ fullpubkey.Set(b, b + 33);
+ CKeyID keyid = fullpubkey.GetID();
+ if (!provider.GetKey(keyid, key)) return false;
+ }
+ }
+
+ // BIP341/BIP342 signing needs lots of precomputed transaction data. While some
+ // (non-SIGHASH_DEFAULT) sighash modes exist that can work with just some subset
+ // of data present, for now, only support signing when everything is provided.
+ if (!m_txdata || !m_txdata->m_bip341_taproot_ready || !m_txdata->m_spent_outputs_ready) return false;
+
+ ScriptExecutionData execdata;
+ execdata.m_annex_init = true;
+ execdata.m_annex_present = false; // Only support annex-less signing for now.
+ if (sigversion == SigVersion::TAPSCRIPT) {
+ execdata.m_codeseparator_pos_init = true;
+ execdata.m_codeseparator_pos = 0xFFFFFFFF; // Only support non-OP_CODESEPARATOR BIP342 signing for now.
+ if (!leaf_hash) return false; // BIP342 signing needs leaf hash.
+ execdata.m_tapleaf_hash_init = true;
+ execdata.m_tapleaf_hash = *leaf_hash;
+ }
+ uint256 hash;
+ if (!SignatureHashSchnorr(hash, execdata, *txTo, nIn, nHashType, sigversion, *m_txdata, MissingDataBehavior::FAIL)) return false;
+ sig.resize(64);
+ if (!key.SignSchnorr(hash, sig, merkle_root, nullptr)) return false;
+ if (nHashType) sig.push_back(nHashType);
return true;
}
@@ -92,6 +155,86 @@ static bool CreateSig(const BaseSignatureCreator& creator, SignatureData& sigdat
return false;
}
+static bool CreateTaprootScriptSig(const BaseSignatureCreator& creator, SignatureData& sigdata, const SigningProvider& provider, std::vector<unsigned char>& sig_out, const XOnlyPubKey& pubkey, const uint256& leaf_hash, SigVersion sigversion)
+{
+ auto lookup_key = std::make_pair(pubkey, leaf_hash);
+ auto it = sigdata.taproot_script_sigs.find(lookup_key);
+ if (it != sigdata.taproot_script_sigs.end()) {
+ sig_out = it->second;
+ }
+ if (creator.CreateSchnorrSig(provider, sig_out, pubkey, &leaf_hash, nullptr, sigversion)) {
+ sigdata.taproot_script_sigs[lookup_key] = sig_out;
+ return true;
+ }
+ return false;
+}
+
+static bool SignTaprootScript(const SigningProvider& provider, const BaseSignatureCreator& creator, SignatureData& sigdata, int leaf_version, const CScript& script, std::vector<valtype>& result)
+{
+ // Only BIP342 tapscript signing is supported for now.
+ if (leaf_version != TAPROOT_LEAF_TAPSCRIPT) return false;
+ SigVersion sigversion = SigVersion::TAPSCRIPT;
+
+ uint256 leaf_hash = (CHashWriter(HASHER_TAPLEAF) << uint8_t(leaf_version) << script).GetSHA256();
+
+ // <xonly pubkey> OP_CHECKSIG
+ if (script.size() == 34 && script[33] == OP_CHECKSIG && script[0] == 0x20) {
+ XOnlyPubKey pubkey(MakeSpan(script).subspan(1, 32));
+ std::vector<unsigned char> sig;
+ if (CreateTaprootScriptSig(creator, sigdata, provider, sig, pubkey, leaf_hash, sigversion)) {
+ result = Vector(std::move(sig));
+ return true;
+ }
+ }
+
+ return false;
+}
+
+static bool SignTaproot(const SigningProvider& provider, const BaseSignatureCreator& creator, const WitnessV1Taproot& output, SignatureData& sigdata, std::vector<valtype>& result)
+{
+ TaprootSpendData spenddata;
+
+ // Gather information about this output.
+ if (provider.GetTaprootSpendData(output, spenddata)) {
+ sigdata.tr_spenddata.Merge(spenddata);
+ }
+
+ // Try key path spending.
+ {
+ std::vector<unsigned char> sig;
+ if (sigdata.taproot_key_path_sig.size() == 0) {
+ if (creator.CreateSchnorrSig(provider, sig, spenddata.internal_key, nullptr, &spenddata.merkle_root, SigVersion::TAPROOT)) {
+ sigdata.taproot_key_path_sig = sig;
+ }
+ }
+ if (sigdata.taproot_key_path_sig.size()) {
+ result = Vector(sigdata.taproot_key_path_sig);
+ return true;
+ }
+ }
+
+ // Try script path spending.
+ std::vector<std::vector<unsigned char>> smallest_result_stack;
+ for (const auto& [key, control_blocks] : sigdata.tr_spenddata.scripts) {
+ const auto& [script, leaf_ver] = key;
+ std::vector<std::vector<unsigned char>> result_stack;
+ if (SignTaprootScript(provider, creator, sigdata, leaf_ver, script, result_stack)) {
+ result_stack.emplace_back(std::begin(script), std::end(script)); // Push the script
+ result_stack.push_back(*control_blocks.begin()); // Push the smallest control block
+ if (smallest_result_stack.size() == 0 ||
+ GetSerializeSize(result_stack, PROTOCOL_VERSION) < GetSerializeSize(smallest_result_stack, PROTOCOL_VERSION)) {
+ smallest_result_stack = std::move(result_stack);
+ }
+ }
+ }
+ if (smallest_result_stack.size() != 0) {
+ result = std::move(smallest_result_stack);
+ return true;
+ }
+
+ return false;
+}
+
/**
* Sign scriptPubKey using signature made with creator.
* Signatures are returned in scriptSigRet (or returns false if scriptPubKey can't be signed),
@@ -113,7 +256,6 @@ static bool SignStep(const SigningProvider& provider, const BaseSignatureCreator
case TxoutType::NONSTANDARD:
case TxoutType::NULL_DATA:
case TxoutType::WITNESS_UNKNOWN:
- case TxoutType::WITNESS_V1_TAPROOT:
return false;
case TxoutType::PUBKEY:
if (!CreateSig(creator, sigdata, provider, sig, CPubKey(vSolutions[0]), scriptPubKey, sigversion)) return false;
@@ -175,6 +317,9 @@ static bool SignStep(const SigningProvider& provider, const BaseSignatureCreator
// Could not find witnessScript, add to missing
sigdata.missing_witness_script = uint256(vSolutions[0]);
return false;
+
+ case TxoutType::WITNESS_V1_TAPROOT:
+ return SignTaproot(provider, creator, WitnessV1Taproot(XOnlyPubKey{vSolutions[0]}), sigdata, ret);
} // no default case, so the compiler can warn about missing cases
assert(false);
}
@@ -205,7 +350,6 @@ bool ProduceSignature(const SigningProvider& provider, const BaseSignatureCreato
bool solved = SignStep(provider, creator, fromPubKey, result, whichType, SigVersion::BASE, sigdata);
bool P2SH = false;
CScript subscript;
- sigdata.scriptWitness.stack.clear();
if (solved && whichType == TxoutType::SCRIPTHASH)
{
@@ -238,10 +382,17 @@ bool ProduceSignature(const SigningProvider& provider, const BaseSignatureCreato
sigdata.scriptWitness.stack = result;
sigdata.witness = true;
result.clear();
+ } else if (whichType == TxoutType::WITNESS_V1_TAPROOT && !P2SH) {
+ sigdata.witness = true;
+ if (solved) {
+ sigdata.scriptWitness.stack = std::move(result);
+ }
+ result.clear();
} else if (solved && whichType == TxoutType::WITNESS_UNKNOWN) {
sigdata.witness = true;
}
+ if (!sigdata.witness) sigdata.scriptWitness.stack.clear();
if (P2SH) {
result.push_back(std::vector<unsigned char>(subscript.begin(), subscript.end()));
}
@@ -402,6 +553,7 @@ class DummySignatureChecker final : public BaseSignatureChecker
public:
DummySignatureChecker() {}
bool CheckECDSASignature(const std::vector<unsigned char>& scriptSig, const std::vector<unsigned char>& vchPubKey, const CScript& scriptCode, SigVersion sigversion) const override { return true; }
+ bool CheckSchnorrSignature(Span<const unsigned char> sig, Span<const unsigned char> pubkey, SigVersion sigversion, const ScriptExecutionData& execdata, ScriptError* serror) const override { return true; }
};
const DummySignatureChecker DUMMY_CHECKER;
@@ -427,6 +579,11 @@ public:
vchSig[6 + m_r_len + m_s_len] = SIGHASH_ALL;
return true;
}
+ bool CreateSchnorrSig(const SigningProvider& provider, std::vector<unsigned char>& sig, const XOnlyPubKey& pubkey, const uint256* leaf_hash, const uint256* tweak, SigVersion sigversion) const override
+ {
+ sig.assign(64, '\000');
+ return true;
+ }
};
}
@@ -476,6 +633,26 @@ bool SignTransaction(CMutableTransaction& mtx, const SigningProvider* keystore,
// Use CTransaction for the constant parts of the
// transaction to avoid rehashing.
const CTransaction txConst(mtx);
+
+ PrecomputedTransactionData txdata;
+ std::vector<CTxOut> spent_outputs;
+ spent_outputs.resize(mtx.vin.size());
+ bool have_all_spent_outputs = true;
+ for (unsigned int i = 0; i < mtx.vin.size(); i++) {
+ CTxIn& txin = mtx.vin[i];
+ auto coin = coins.find(txin.prevout);
+ if (coin == coins.end() || coin->second.IsSpent()) {
+ have_all_spent_outputs = false;
+ } else {
+ spent_outputs[i] = CTxOut(coin->second.out.nValue, coin->second.out.scriptPubKey);
+ }
+ }
+ if (have_all_spent_outputs) {
+ txdata.Init(txConst, std::move(spent_outputs), true);
+ } else {
+ txdata.Init(txConst, {}, true);
+ }
+
// Sign what we can:
for (unsigned int i = 0; i < mtx.vin.size(); i++) {
CTxIn& txin = mtx.vin[i];
@@ -490,7 +667,7 @@ bool SignTransaction(CMutableTransaction& mtx, const SigningProvider* keystore,
SignatureData sigdata = DataFromTransaction(mtx, i, coin->second.out);
// Only sign SIGHASH_SINGLE if there's a corresponding output:
if (!fHashSingle || (i < mtx.vout.size())) {
- ProduceSignature(*keystore, MutableTransactionSignatureCreator(&mtx, i, amount, nHashType), prevPubKey, sigdata);
+ ProduceSignature(*keystore, MutableTransactionSignatureCreator(&mtx, i, amount, &txdata, nHashType), prevPubKey, sigdata);
}
UpdateInput(txin, sigdata);
@@ -502,7 +679,7 @@ bool SignTransaction(CMutableTransaction& mtx, const SigningProvider* keystore,
}
ScriptError serror = SCRIPT_ERR_OK;
- if (!VerifyScript(txin.scriptSig, prevPubKey, &txin.scriptWitness, STANDARD_SCRIPT_VERIFY_FLAGS, TransactionSignatureChecker(&txConst, i, amount, MissingDataBehavior::FAIL), &serror)) {
+ if (!VerifyScript(txin.scriptSig, prevPubKey, &txin.scriptWitness, STANDARD_SCRIPT_VERIFY_FLAGS, TransactionSignatureChecker(&txConst, i, amount, txdata, MissingDataBehavior::FAIL), &serror)) {
if (serror == SCRIPT_ERR_INVALID_STACK_OPERATION) {
// Unable to sign input and verification failed (possible attempt to partially sign).
input_errors[i] = "Unable to sign input, invalid stack size (possibly missing key)";
diff --git a/src/script/sign.h b/src/script/sign.h
index a1cfe1574d..b4e7318892 100644
--- a/src/script/sign.h
+++ b/src/script/sign.h
@@ -11,13 +11,13 @@
#include <pubkey.h>
#include <script/interpreter.h>
#include <script/keyorigin.h>
+#include <script/standard.h>
#include <span.h>
#include <streams.h>
class CKey;
class CKeyID;
class CScript;
-class CScriptID;
class CTransaction;
class SigningProvider;
@@ -31,6 +31,7 @@ public:
/** Create a singular (non-script) signature. */
virtual bool CreateSig(const SigningProvider& provider, std::vector<unsigned char>& vchSig, const CKeyID& keyid, const CScript& scriptCode, SigVersion sigversion) const =0;
+ virtual bool CreateSchnorrSig(const SigningProvider& provider, std::vector<unsigned char>& sig, const XOnlyPubKey& pubkey, const uint256* leaf_hash, const uint256* merkle_root, SigVersion sigversion) const =0;
};
/** A signature creator for transactions. */
@@ -40,11 +41,14 @@ class MutableTransactionSignatureCreator : public BaseSignatureCreator {
int nHashType;
CAmount amount;
const MutableTransactionSignatureChecker checker;
+ const PrecomputedTransactionData* m_txdata;
public:
MutableTransactionSignatureCreator(const CMutableTransaction* txToIn, unsigned int nInIn, const CAmount& amountIn, int nHashTypeIn = SIGHASH_ALL);
+ MutableTransactionSignatureCreator(const CMutableTransaction* txToIn, unsigned int nInIn, const CAmount& amountIn, const PrecomputedTransactionData* txdata, int nHashTypeIn = SIGHASH_ALL);
const BaseSignatureChecker& Checker() const override { return checker; }
bool CreateSig(const SigningProvider& provider, std::vector<unsigned char>& vchSig, const CKeyID& keyid, const CScript& scriptCode, SigVersion sigversion) const override;
+ bool CreateSchnorrSig(const SigningProvider& provider, std::vector<unsigned char>& sig, const XOnlyPubKey& pubkey, const uint256* leaf_hash, const uint256* merkle_root, SigVersion sigversion) const override;
};
/** A signature creator that just produces 71-byte empty signatures. */
@@ -64,8 +68,11 @@ struct SignatureData {
CScript redeem_script; ///< The redeemScript (if any) for the input
CScript witness_script; ///< The witnessScript (if any) for the input. witnessScripts are used in P2WSH outputs.
CScriptWitness scriptWitness; ///< The scriptWitness of an input. Contains complete signatures or the traditional partial signatures format. scriptWitness is part of a transaction input per BIP 144.
+ TaprootSpendData tr_spenddata; ///< Taproot spending data.
std::map<CKeyID, SigPair> signatures; ///< BIP 174 style partial signatures for the input. May contain all signatures necessary for producing a final scriptSig or scriptWitness.
std::map<CKeyID, std::pair<CPubKey, KeyOriginInfo>> misc_pubkeys;
+ std::vector<unsigned char> taproot_key_path_sig; /// Schnorr signature for key path spending
+ std::map<std::pair<XOnlyPubKey, uint256>, std::vector<unsigned char>> taproot_script_sigs; ///< (Partial) schnorr signatures, indexed by XOnlyPubKey and leaf_hash.
std::vector<CKeyID> missing_pubkeys; ///< KeyIDs of pubkeys which could not be found
std::vector<CKeyID> missing_sigs; ///< KeyIDs of pubkeys for signatures which could not be found
uint160 missing_redeem_script; ///< ScriptID of the missing redeemScript (if any)
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..285dd4c116 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 +210,50 @@ CScript GetScriptForRawPubKey(const CPubKey& pubkey);
/** Generate a multisig script. */
CScript GetScriptForMultisig(int nRequired, const std::vector<CPubKey>& keys);
+struct ShortestVectorFirstComparator
+{
+ bool operator()(const std::vector<unsigned char>& a, const std::vector<unsigned char>& b) const
+ {
+ if (a.size() < b.size()) return true;
+ if (a.size() > b.size()) return false;
+ return a < b;
+ }
+};
+
+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.
+ * The control blocks are sorted by size, so that the signing logic can
+ * easily prefer the cheapest one. */
+ std::map<std::pair<CScript, int>, std::set<std::vector<unsigned char>, ShortestVectorFirstComparator>> 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 +296,8 @@ 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 +306,9 @@ 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 +323,8 @@ 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 2024-10-27 19:14:34 +0000