Fuzz test for BIP324 key derivation

src/Makefile.test.include

@@ -220,6 +220,7 @@ test_fuzz_fuzz_SOURCES = \
  test/fuzz/banman.cpp \
  test/fuzz/base_encode_decode.cpp \
  test/fuzz/bech32.cpp \
+ test/fuzz/bip324.cpp \
  test/fuzz/block.cpp \
  test/fuzz/block_header.cpp \
  test/fuzz/blockfilter.cpp \

src/test/fuzz/bip324.cpp

@@ -0,0 +1,41 @@
+// Copyright (c) 2021 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 <chainparams.h>
+#include <crypto/bip324.h>
+#include <key.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+
+void initialize_chainparams()
+{
+    SelectParams(CBaseChainParams::REGTEST);
+}
+
+FUZZ_TARGET_INIT(bip324, initialize_chainparams)
+{
+    FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
+
+    ECDHSecret ecdh_secret;
+    ecdh_secret.resize(ECDH_SECRET_SIZE);
+    auto ecdh_secret_bytes = fuzzed_data_provider.ConsumeBytes<uint8_t>(ECDH_SECRET_SIZE);
+    ecdh_secret_bytes.resize(ECDH_SECRET_SIZE);
+
+    memcpy(ecdh_secret.data(), ecdh_secret_bytes.data(), ECDH_SECRET_SIZE);
+
+    auto initiator_hdata_len = fuzzed_data_provider.ConsumeIntegralInRange(0, 4096);
+    auto initiator_hdata = fuzzed_data_provider.ConsumeBytes<uint8_t>(initiator_hdata_len);
+
+    auto responder_hdata_len = fuzzed_data_provider.ConsumeIntegralInRange(0, 4096);
+    auto responder_hdata = fuzzed_data_provider.ConsumeBytes<uint8_t>(responder_hdata_len);
+
+    BIP324Keys keys;
+    assert(derive_bip324_keys(std::move(ecdh_secret), initiator_hdata, responder_hdata, keys));
+    assert(keys.initiator_F.size() == BIP324_KEY_LEN);
+    assert(keys.initiator_V.size() == BIP324_KEY_LEN);
+    assert(keys.responder_F.size() == BIP324_KEY_LEN);
+    assert(keys.responder_V.size() == BIP324_KEY_LEN);
+    assert(keys.session_id.size() == BIP324_KEY_LEN);
+    assert("0000000000000000000000000000000000000000000000000000000000000000" == HexStr(ecdh_secret));
+}