Merge bitcoin/bitcoin#23394: Taproot wallet test vectors (generation+tests)

f1c33ee4ac1056289f2e67b75755388549ada4ca tests: implement BIP341 test vectors (Pieter Wuille)
ac3037df1196b1d95ade2dfad4699ad3a6074903 tests: BIP341 test vector generation (Pieter Wuille)
ca83ffc2ea5fe08f16fff7df71c040d067f2afb0 tests: add deterministic signing mode to ECDSA (Pieter Wuille)
c98c53f20cadeda53f6a9323f72363593d174f68 tests: abstract out precomputed BIP341 signature hash elements (Pieter Wuille)
a5bde018b42cd38979fee71d870e0140b10c73d6 tests: give feature_taproot access to sighash preimages (Pieter Wuille)
51408250969e7ed171378369a995c90d4f813189 tests: add more fields to TaprootInfo (Pieter Wuille)
2478c6730a81dda3c56cb99087caf6abe49c85f5 Make signing follow BIP340 exactly w.r.t. aux randomness (Pieter Wuille)

Pull request description:

  This PR adds code to `test/functional/feature_taproot.py` which runs through a (deterministic) scenario covering several aspects of the wallet side of BIP341 (scriptPubKey computation from keys/scripts, control block computation, key path spending), with the ability to output test vectors in mediawiki format based on this scenario. The generated tests are then also included directly in `src/test/script_tests.cpp` and `src/test/script_standard_tests.cpp`.

  I intend to add these test vectors to BIP341 itself: https://github.com/bitcoin/bips/pull/1225

ACKs for top commit:
  laanwj:
    Code review ACK f1c33ee4ac1056289f2e67b75755388549ada4ca

Tree-SHA512: fcf7109539cb214d3190516b205cd32d2b1b452f14aa66f4107acfaa8bfc7d368f626857f1935665a4342eabc0b9ee8aba608a7c0a2494bec0b498e723439c9d

1 files changed, 76 insertions, 0 deletions

diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
index 2c39cbffb9..a89eab68e9 100644
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -3,6 +3,7 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <test/data/script_tests.json.h>
+#include <test/data/bip341_wallet_vectors.json.h>
 
 #include <core_io.h>
 #include <fs.h>
@@ -1743,4 +1744,79 @@ BOOST_AUTO_TEST_CASE(script_assets_test)
     file.close();
 }
 
+BOOST_AUTO_TEST_CASE(bip341_keypath_test_vectors)
+{
+    UniValue tests;
+    tests.read((const char*)json_tests::bip341_wallet_vectors, sizeof(json_tests::bip341_wallet_vectors));
+
+    const auto& vectors = tests["keyPathSpending"];
+
+    for (const auto& vec : vectors.getValues()) {
+        auto txhex = ParseHex(vec["given"]["rawUnsignedTx"].get_str());
+        CMutableTransaction tx;
+        VectorReader(SER_NETWORK, PROTOCOL_VERSION, txhex, 0) >> tx;
+        std::vector<CTxOut> utxos;
+        for (const auto& utxo_spent : vec["given"]["utxosSpent"].getValues()) {
+            auto script_bytes = ParseHex(utxo_spent["scriptPubKey"].get_str());
+            CScript script{script_bytes.begin(), script_bytes.end()};
+            CAmount amount{utxo_spent["amountSats"].get_int()};
+            utxos.emplace_back(amount, script);
+        }
+
+        PrecomputedTransactionData txdata;
+        txdata.Init(tx, std::vector<CTxOut>{utxos}, true);
+
+        BOOST_CHECK(txdata.m_bip341_taproot_ready);
+        BOOST_CHECK_EQUAL(HexStr(txdata.m_spent_amounts_single_hash), vec["intermediary"]["hashAmounts"].get_str());
+        BOOST_CHECK_EQUAL(HexStr(txdata.m_outputs_single_hash), vec["intermediary"]["hashOutputs"].get_str());
+        BOOST_CHECK_EQUAL(HexStr(txdata.m_prevouts_single_hash), vec["intermediary"]["hashPrevouts"].get_str());
+        BOOST_CHECK_EQUAL(HexStr(txdata.m_spent_scripts_single_hash), vec["intermediary"]["hashScriptPubkeys"].get_str());
+        BOOST_CHECK_EQUAL(HexStr(txdata.m_sequences_single_hash), vec["intermediary"]["hashSequences"].get_str());
+
+        for (const auto& input : vec["inputSpending"].getValues()) {
+            int txinpos = input["given"]["txinIndex"].get_int();
+            int hashtype = input["given"]["hashType"].get_int();
+
+            // Load key.
+            auto privkey = ParseHex(input["given"]["internalPrivkey"].get_str());
+            CKey key;
+            key.Set(privkey.begin(), privkey.end(), true);
+
+            // Load Merkle root.
+            uint256 merkle_root;
+            if (!input["given"]["merkleRoot"].isNull()) {
+                merkle_root = uint256{ParseHex(input["given"]["merkleRoot"].get_str())};
+            }
+
+            // Compute and verify (internal) public key.
+            XOnlyPubKey pubkey{key.GetPubKey()};
+            BOOST_CHECK_EQUAL(HexStr(pubkey), input["intermediary"]["internalPubkey"].get_str());
+
+            // Sign and verify signature.
+            FlatSigningProvider provider;
+            provider.keys[key.GetPubKey().GetID()] = key;
+            MutableTransactionSignatureCreator creator(&tx, txinpos, utxos[txinpos].nValue, &txdata, hashtype);
+            std::vector<unsigned char> signature;
+            BOOST_CHECK(creator.CreateSchnorrSig(provider, signature, pubkey, nullptr, &merkle_root, SigVersion::TAPROOT));
+            BOOST_CHECK_EQUAL(HexStr(signature), input["expected"]["witness"][0].get_str());
+
+            // We can't observe the tweak used inside the signing logic, so verify by recomputing it.
+            BOOST_CHECK_EQUAL(HexStr(pubkey.ComputeTapTweakHash(merkle_root.IsNull() ? nullptr : &merkle_root)), input["intermediary"]["tweak"].get_str());
+
+            // We can't observe the sighash used inside the signing logic, so verify by recomputing it.
+            ScriptExecutionData sed;
+            sed.m_annex_init = true;
+            sed.m_annex_present = false;
+            uint256 sighash;
+            BOOST_CHECK(SignatureHashSchnorr(sighash, sed, tx, txinpos, hashtype, SigVersion::TAPROOT, txdata, MissingDataBehavior::FAIL));
+            BOOST_CHECK_EQUAL(HexStr(sighash), input["intermediary"]["sigHash"].get_str());
+
+            // To verify the sigmsg, hash the expected sigmsg, and compare it with the (expected) sighash.
+            BOOST_CHECK_EQUAL(HexStr((CHashWriter(HASHER_TAPSIGHASH) << MakeSpan(ParseHex(input["intermediary"]["sigMsg"].get_str()))).GetSHA256()), input["intermediary"]["sigHash"].get_str());
+        }
+
+    }
+
+}
+
 BOOST_AUTO_TEST_SUITE_END()