[test] Add BIP 328 test vectors for Musig2
What the developer wrote
Authored by w0xlt
[test] Add BIP 328 test vectors for Musig2
What changed, and why it matters
This commit only adds new test code. It introduces test vectors for BIP 328 (a Bitcoin improvement proposal related to the MuSig2 multi-signature scheme) to verify that public-key aggregation and synthetic extended-public-key generation produce expected outputs. No production code is changed, so it cannot directly introduce a runtime security vulnerability.
No security action required. Review the test vectors for correctness if desired, and ensure the new test file compiles and passes in CI.
Security signals we found
No changes to production code paths
Only test coverage added for existing MuSig2 aggregation helpers
Hard-coded test vectors are public BIP 328 vectors, not secrets
No input parsing, deserialization, or network handling changes
Evidence from the diff
The diff adds src/test/bip328_tests.cpp to the Bitcoin Core unit-test suite and registers it in src/test/CMakeLists.txt. The new file contains Boost.Test test cases that parse hard-coded secp256k1 public keys, call MuSig2AggregatePubkeys() and CreateMuSig2SyntheticXpub(), and assert the results match known BIP 328 test vectors. It also checks that an invalid public key causes aggregation to return std::nullopt. The commit does not modify any consensus, wallet, networking, or cryptographic implementation code.
Changed components
src/test/bip328_tests.cpp (new unit test file)src/test/CMakeLists.txt (test build registration)Inspect captured patch +115 / −0
diff --git a/src/test/CMakeLists.txt b/src/test/CMakeLists.txt
index 83cb989a..6e7b688a 100644
--- a/src/test/CMakeLists.txt
+++ b/src/test/CMakeLists.txt
@@ -62,6 +62,7 @@ add_executable(test_bitcoin
miniscript_tests.cpp
minisketch_tests.cpp
multisig_tests.cpp
+ bip328_tests.cpp
net_peer_connection_tests.cpp
net_peer_eviction_tests.cpp
net_tests.cpp
diff --git a/src/test/bip328_tests.cpp b/src/test/bip328_tests.cpp
new file mode 100644
index 00000000..9fffa00b
--- /dev/null
+++ b/src/test/bip328_tests.cpp
@@ -0,0 +1,114 @@
+// Copyright (c) 2026-present The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <boost/test/unit_test.hpp>
+
+#include <key.h>
+#include <key_io.h>
+#include <musig.h>
+#include <test/util/setup_common.h>
+#include <util/strencodings.h>
+#include <crypto/hex_base.h>
+
+#include <string>
+#include <vector>
+
+namespace {
+
+struct BIP328TestVector {
+ std::vector<std::string> pubkeys;
+ std::string expected_aggregate_pubkey;
+ std::string expected_aggregate_xpub;
+};
+
+BOOST_FIXTURE_TEST_SUITE(bip328_tests, BasicTestingSetup)
+
+BOOST_AUTO_TEST_CASE(valid_keys)
+{
+ // BIP 328 test vectors
+ std::vector<BIP328TestVector> test_vectors = {
+ // Test vector 0
+ {
+ .pubkeys = {
+ "03935F972DA013F80AE011890FA89B67A27B7BE6CCB24D3274D18B2D4067F261A9",
+ "02F9308A019258C31049344F85F89D5229B531C845836F99B08601F113BCE036F9"
+ },
+ .expected_aggregate_pubkey = "0354240c76b8f2999143301a99c7f721ee57eee0bce401df3afeaa9ae218c70f23",
+ .expected_aggregate_xpub = "xpub661MyMwAqRbcFt6tk3uaczE1y6EvM1TqXvawXcYmFEWijEM4PDBnuCXwwXEKGEouzXE6QLLRxjatMcLLzJ5LV5Nib1BN7vJg6yp45yHHRbm"
+ },
+ // Test vector 1
+ {
+ .pubkeys = {
+ "02F9308A019258C31049344F85F89D5229B531C845836F99B08601F113BCE036F9",
+ "03DFF1D77F2A671C5F36183726DB2341BE58FEAE1DA2DECED843240F7B502BA659",
+ "023590A94E768F8E1815C2F24B4D80A8E3149316C3518CE7B7AD338368D038CA66"
+ },
+ .expected_aggregate_pubkey = "0290539eede565f5d054f32cc0c220126889ed1e5d193baf15aef344fe59d4610c",
+ .expected_aggregate_xpub = "xpub661MyMwAqRbcFt6tk3uaczE1y6EvM1TqXvawXcYmFEWijEM4PDBnuCXwwVk5TFJk8Tw5WAdV3DhrGfbFA216sE9BsQQiSFTdudkETnKdg8k"
+ },
+ // Test vector 2
+ {
+ .pubkeys = {
+ "02DFF1D77F2A671C5F36183726DB2341BE58FEAE1DA2DECED843240F7B502BA659",
+ "023590A94E768F8E1815C2F24B4D80A8E3149316C3518CE7B7AD338368D038CA66",
+ "02F9308A019258C31049344F85F89D5229B531C845836F99B08601F113BCE036F9",
+ "03935F972DA013F80AE011890FA89B67A27B7BE6CCB24D3274D18B2D4067F261A9"
+ },
+ .expected_aggregate_pubkey = "022479f134cdb266141dab1a023cbba30a870f8995b95a91fc8464e56a7d41f8ea",
+ .expected_aggregate_xpub = "xpub661MyMwAqRbcFt6tk3uaczE1y6EvM1TqXvawXcYmFEWijEM4PDBnuCXwwUvaZYpysLX4wN59tjwU5pBuDjNrPEJbfxjLwn7ruzbXTcUTHkZ"
+ }
+ };
+
+ // Iterate through all test vectors
+ for (int i = 0; i < (int) test_vectors.size(); ++i) {
+ const auto& test = test_vectors[i];
+
+ // Parse public keys
+ std::vector<CPubKey> pubkeys;
+ for (const auto& hex_pubkey : test.pubkeys) {
+ std::vector<unsigned char> data = ParseHex(hex_pubkey);
+ CPubKey pubkey(data.begin(), data.end());
+ pubkeys.push_back(pubkey);
+ }
+
+ // Aggregate public keys
+ std::optional<CPubKey> m_aggregate_pubkey = MuSig2AggregatePubkeys(pubkeys);
+ BOOST_CHECK_MESSAGE(m_aggregate_pubkey.has_value(), "Test vector " << i << ": Failed to aggregate pubkeys");
+
+ // Check aggregate pubkey
+ std::string combined_keys = HexStr(m_aggregate_pubkey.value());
+ BOOST_CHECK_MESSAGE(combined_keys == test.expected_aggregate_pubkey, "Test vector " << i << ": Aggregate pubkey mismatch");
+
+ // Create extended public key
+ CExtPubKey extpub = CreateMuSig2SyntheticXpub(m_aggregate_pubkey.value());
+
+ // Check xpub
+ std::string xpub = EncodeExtPubKey(extpub);
+ BOOST_CHECK_MESSAGE(xpub == test.expected_aggregate_xpub, "Test vector " << i << ": Synthetic xpub mismatch");
+ }
+}
+
+BOOST_AUTO_TEST_CASE(invalid_key)
+{
+ std::vector<std::string> test_vectors = {
+ "00ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+ "02DFF1D77F2A671C5F36183726DB2341BE58FEAE1DA2DECED843240F7B502BA659"
+ };
+
+ // Parse public keys
+ std::vector<CPubKey> pubkeys;
+ for (const auto& hex_pubkey : test_vectors) {
+ std::vector<unsigned char> data = ParseHex(hex_pubkey);
+ CPubKey pubkey(data.begin(), data.end());
+ pubkeys.push_back(pubkey);
+ }
+
+ // Aggregate public keys
+ std::optional<CPubKey> m_aggregate_pubkey = MuSig2AggregatePubkeys(pubkeys);
+ BOOST_CHECK_MESSAGE(!m_aggregate_pubkey.has_value(), "Aggregate key with an invalid public key is null");
+}
+
+BOOST_AUTO_TEST_SUITE_END()
+
+}
Why this scored 15/100
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