READ THE CODE

Inside Bitcoin

The code behind the network, with room to understand it.

Stable release v32.1bitcoin/bitcoin · f0de87f04062 ↗3,020 source files · 47.5 MB stored on the server440 file guides

Release published 2026-10-28 · Snapshot fetched 2026-11-01. Latest stable release at fetch time; development branches and Git history are excluded. Only the selected code window and visible folders load here.

4,612 bytes · SHA-256 e4c9f5b1343902f8… · View upstream ↗

1// Copyright (c) 2012-present The Bitcoin Core developers
2// Distributed under the MIT software license, see the accompanying
3// file COPYING or http://www.opensource.org/licenses/mit-license.php.
4
5#include <consensus/merkle.h>
6#include <merkleblock.h>
7#include <serialize.h>
8#include <streams.h>
9#include <test/util/random.h>
10#include <test/util/setup_common.h>
11#include <uint256.h>
12
13#include <vector>
14
15#include <boost/test/unit_test.hpp>
16
17class CPartialMerkleTreeTester : public CPartialMerkleTree
18{
19public:
20    CPartialMerkleTreeTester(FastRandomContext& rng) : m_rng{rng} {}
21
22    // flip one bit in one of the hashes - this should break the authentication
23    void Damage() {
24        unsigned int n = m_rng.randrange(vHash.size());
25        int bit = m_rng.randbits(8);
26        *(vHash[n].begin() + (bit>>3)) ^= 1<<(bit&7);
27    }
28
29    FastRandomContext& m_rng;
30};
31
32BOOST_FIXTURE_TEST_SUITE(pmt_tests, BasicTestingSetup)
33
34BOOST_AUTO_TEST_CASE(pmt_test1)
35{
36    static const unsigned int tx_counts[] = {1, 4, 7, 17, 56, 100, 127, 256, 312, 513, 1000, 4095};
37
38    for (int i = 0; i < 12; i++) {
39        unsigned int nTx = tx_counts[i];
40
41        // build a block with some dummy transactions
42        CBlock block;
43        for (unsigned int j=0; j<nTx; j++) {
44            CMutableTransaction tx;
45            tx.nLockTime = j; // actual transaction data doesn't matter; just make the nLockTime's unique
46            block.vtx.push_back(MakeTransactionRef(std::move(tx)));
47        }
48
49        // calculate actual merkle root and height
50        uint256 merkleRoot1 = BlockMerkleRoot(block);
51        std::vector<Txid> vTxid(nTx);
52        for (unsigned int j=0; j<nTx; j++)
53            vTxid[j] = block.vtx[j]->GetHash();
54        int nHeight = 1, nTx_ = nTx;
55        while (nTx_ > 1) {
56            nTx_ = (nTx_+1)/2;
57            nHeight++;
58        }
59
60        // check with random subsets with inclusion chances 1, 1/2, 1/4, ..., 1/128
61        for (int att = 1; att < 15; att++) {
62            // build random subset of txid's
63            std::vector<bool> vMatch(nTx, false);
64            std::vector<Txid> vMatchTxid1;
65            for (unsigned int j=0; j<nTx; j++) {
66                bool fInclude = m_rng.randbits(att / 2) == 0;
67                vMatch[j] = fInclude;
68                if (fInclude)
69                    vMatchTxid1.push_back(vTxid[j]);
70            }
71
72            // build the partial merkle tree
73            CPartialMerkleTree pmt1(vTxid, vMatch);
74
75            // serialize
76            DataStream ss{};
77            ss << pmt1;
78
79            // verify CPartialMerkleTree's size guarantees
80            unsigned int n = std::min<unsigned int>(nTx, 1 + vMatchTxid1.size()*nHeight);
81            BOOST_CHECK(ss.size() <= 10 + (258*n+7)/8);
82
83            // deserialize into a tester copy
84            CPartialMerkleTreeTester pmt2{m_rng};
85            ss >> pmt2;
86
87            // extract merkle root and matched txids from copy
88            std::vector<Txid> vMatchTxid2;
89            std::vector<unsigned int> vIndex;
90            uint256 merkleRoot2 = pmt2.ExtractMatches(vMatchTxid2, vIndex);
91
92            // check that it has the same merkle root as the original, and a valid one
93            BOOST_CHECK(merkleRoot1 == merkleRoot2);
94            BOOST_CHECK(!merkleRoot2.IsNull());
95
96            // check that it contains the matched transactions (in the same order!)
97            BOOST_CHECK(vMatchTxid1 == vMatchTxid2);
98
99            // check that random bit flips break the authentication
100            for (int j=0; j<4; j++) {
101                CPartialMerkleTreeTester pmt3(pmt2);
102                pmt3.Damage();
103                std::vector<Txid> vMatchTxid3;
104                uint256 merkleRoot3 = pmt3.ExtractMatches(vMatchTxid3, vIndex);
105                BOOST_CHECK(merkleRoot3 != merkleRoot1);
106            }
107        }
108    }
109}
110
111BOOST_AUTO_TEST_CASE(pmt_malleability)
112{
113    std::vector<Txid> vTxid{
114        Txid::FromUint256(uint256{1}), Txid::FromUint256(uint256{2}),
115        Txid::FromUint256(uint256{3}), Txid::FromUint256(uint256{4}),
116        Txid::FromUint256(uint256{5}), Txid::FromUint256(uint256{6}),
117        Txid::FromUint256(uint256{7}), Txid::FromUint256(uint256{8}),
118        Txid::FromUint256(uint256{9}), Txid::FromUint256(uint256{10}),
119        Txid::FromUint256(uint256{9}), Txid::FromUint256(uint256{10}),
120    };
121    std::vector<bool> vMatch = {false, false, false, false, false, false, false, false, false, true, true, false};
122
123    CPartialMerkleTree tree(vTxid, vMatch);
124    std::vector<unsigned int> vIndex;
125    BOOST_CHECK(tree.ExtractMatches(vTxid, vIndex).IsNull());
126}
127
128BOOST_AUTO_TEST_SUITE_END()
129

src/wallet/receive.cpp

src/wallet/coinselection.cpp

src/consensus/validation.h

src/primitives/transaction.cpp

src/script/descriptor.cpp

src/bitcoin-cli.cpp

src/rpc/blockchain.cpp

src/rpc/rawtransaction.cpp

src/init.cpp

src/crypto/sha256.cpp

src/consensus/merkle.h

src/consensus/tx_check.h

src/consensus/tx_verify.h

src/policy/feerate.h

src/policy/feerate.cpp

src/primitives/transaction_identifier.h

src/chainparamsbase.h

src/chainparamsbase.cpp

src/util/moneystr.cpp

src/crypto/ripemd160.h

src/crypto/sha1.h

src/crypto/sha512.h

src/crypto/hmac_sha256.h

src/crypto/hmac_sha512.h

src/crypto/hmac_sha256.cpp

src/crypto/hmac_sha512.cpp

src/crypto/hkdf_sha256_32.h

src/crypto/hkdf_sha256_32.cpp

src/support/cleanse.h

src/support/cleanse.cpp

src/crypto/siphash.cpp

src/crypto/muhash.h

src/crypto/chacha20.h

src/crypto/poly1305.h

src/crypto/chacha20poly1305.h

src/crypto/chacha20poly1305.cpp

src/util/chaintype.cpp

src/util/obfuscation.h

src/util/byte_units.h

src/util/overflow.h

src/blockencodings.cpp

src/net_permissions.cpp

src/policy/packages.cpp

src/policy/rbf.cpp

src/policy/truc_policy.cpp

src/policy/ephemeral_policy.cpp

src/policy/settings.cpp

src/policy/policy.cpp

src/node/transaction.cpp

src/node/coin.cpp

src/rpc/client.cpp

src/rpc/external_signer.cpp

src/rpc/request.cpp

src/rpc/server_util.cpp

src/rpc/fees.cpp

src/rpc/output_script.cpp

src/rpc/rawtransaction_util.cpp

src/rpc/rawtransaction_util.h

src/rpc/register.h

src/rpc/request.h

src/rpc/server_util.h

src/rpc/protocol.h

src/rpc/server.h

src/rpc/signmessage.cpp

src/rpc/txoutproof.cpp

src/rpc/util.cpp

src/rpc/util.h

src/wallet/rpc/addresses.cpp

src/wallet/rpc/backup.cpp

src/wallet/rpc/coins.cpp

src/wallet/rpc/encrypt.cpp

src/wallet/rpc/signmessage.cpp

src/wallet/rpc/util.cpp

src/wallet/rpc/util.h

src/wallet/coincontrol.cpp

src/wallet/coincontrol.h

src/wallet/context.cpp

src/wallet/context.h

src/wallet/crypter.cpp

src/wallet/crypter.h

src/wallet/db.cpp

src/wallet/export.cpp

src/wallet/external_signer_scriptpubkeyman.cpp

src/wallet/rpc/spend.cpp

src/wallet/rpc/transactions.cpp

src/wallet/rpc/wallet.cpp

src/wallet/feebumper.cpp

src/wallet/feebumper.h

src/index/base.h

src/index/base.cpp

src/index/txindex.h

src/index/txindex.cpp

src/index/txindex_key.h

src/index/txospenderindex.h

src/index/txospenderindex.cpp

src/index/blockfilterindex.h

src/index/blockfilterindex.cpp

src/index/coinstatsindex.h

src/index/coinstatsindex.cpp

src/index/db_key.h

src/index/disktxpos.h

src/kernel/chain.cpp

src/kernel/chain.h

src/kernel/checks.cpp

src/kernel/checks.h

src/kernel/context.cpp

src/kernel/context.h

src/kernel/cs_main.cpp

src/kernel/cs_main.h

src/kernel/disconnected_transactions.cpp

src/kernel/disconnected_transactions.h

src/kernel/mempool_removal_reason.cpp

src/kernel/mempool_removal_reason.h

src/kernel/coinstats.cpp

src/kernel/coinstats.h

src/kernel/chainparams.cpp

src/kernel/chainparams.h

src/wallet/sqlite.cpp

src/wallet/sqlite.h

src/wallet/transaction.cpp

src/wallet/transaction.h

src/wallet/dump.cpp

src/wallet/dump.h

src/wallet/init.cpp

src/wallet/walletutil.cpp

src/wallet/walletutil.h

src/wallet/wallettool.cpp

src/wallet/wallettool.h

src/wallet/export.h

src/wallet/migrate.cpp

src/wallet/migrate.h

src/wallet/db.h

src/wallet/walletdb.cpp

src/wallet/interfaces.cpp

src/wallet/scriptpubkeyman.cpp

src/wallet/scriptpubkeyman.h

src/kernel/bitcoinkernel.cpp

src/kernel/bitcoinkernel.h

src/kernel/bitcoinkernel_wrapper.h

src/node/chainstate.cpp

src/node/chainstate.h

src/node/blockstorage.cpp

src/node/blockstorage.h

src/node/mempool_persist.cpp

src/node/mempool_persist.h

src/node/utxo_snapshot.cpp

src/node/utxo_snapshot.h

src/node/kernel_notifications.cpp

src/node/kernel_notifications.h

src/node/blockmanager_args.cpp

src/kernel/blockmanager_opts.h

src/util/expected.cpp

src/policy/settings.h

src/util/types.h

src/kernel/messagestartchars.h

src/kernel/warning.h

src/util/exception.h

src/common/license_info.h

src/node/coins_view_args.h

src/node/database_args.h

src/util/batchpriority.h

src/util/ui_change_type.h

src/node/coins_view_args.cpp

src/node/peerman_args.h

src/util/serfloat.h

src/node/blockmanager_args.h

src/node/database_args.cpp

src/util/overloaded.h

src/interfaces/types.h

src/node/chainstatemanager_args.h

src/node/minisketchwrapper.h

src/util/macros.h

src/util/syserror.h

src/common/run_command.h

src/util/bytevectorhash.cpp

src/node/mempool_persist_args.cpp

src/util/exec.h

src/util/rbf.h

src/crypto/hex_base.h

src/node/mempool_persist_args.h

src/interfaces/echo.h

src/util/any.h

src/util/batchpriority.cpp

src/util/threadnames.h

src/node/coin.h

src/node/mempool_args.h

src/util/asmap.h

src/util/bytevectorhash.h

src/node/context.cpp

src/util/insert.h

src/util/readwritefile.h

src/node/peerman_args.cpp

src/node/interface_ui.cpp

src/interfaces/handler.h

src/node/mining_args.h

src/util/hasher.cpp

src/common/init.h

src/kernel/mempool_limits.h

src/common/system.h

src/crypto/sha3.h

src/util/threadinterrupt.cpp

src/node/protocol_version.h

src/util/exception.cpp

src/common/messages.h

src/node/connection_types.cpp

src/util/bip32.h

src/common/license_info.cpp

src/util/stdmutex.h

src/common/run_command.cpp

src/util/check.cpp

src/util/golombrice.h

src/node/types.h

src/node/timeoffsets.h

src/util/readwritefile.cpp

src/util/fastrange.h

src/util/signalinterrupt.h

src/util/task_runner.h

src/util/syserror.cpp

src/common/interfaces.cpp

src/common/types.h

src/util/threadinterrupt.h

src/kernel/chainstatemanager_opts.h

src/node/psbt.h

src/policy/ephemeral_policy.h

src/util/trace.h

src/common/url.cpp

src/kernel/mempool_options.h

src/util/serfloat.cpp

src/kernel/notifications_interface.h

src/node/timeoffsets.cpp

src/node/warnings.cpp

src/util/hash_type.h

src/crypto/hex_base.cpp

src/node/eviction.h

src/util/tokenbucket.h

src/crypto/aes.h

src/common/pcp.h

src/util/feefrac.cpp

src/node/transaction.h

src/util/threadnames.cpp

src/common/signmessage.h

src/util/exec.cpp

src/util/signalinterrupt.cpp

src/clientversion.cpp

src/common/signmessage.cpp

src/compat/assumptions.h

src/compat/byteswap.h

src/deploymentinfo.cpp

src/deploymentinfo.h

src/deploymentstatus.cpp

src/deploymentstatus.h

src/dummywallet.cpp

src/external_signer.h

src/init/bitcoin-gui.cpp

src/init/bitcoin-node.cpp

src/init/bitcoin-qt.cpp

src/init/bitcoin-wallet.cpp

src/init/bitcoind.cpp

src/init/common.h

src/interfaces/init.h

src/interfaces/ipc.h

src/key_io.h

src/logging/categories.h

src/logging/timer.h

src/mapport.h

src/musig.h

src/net_permissions.h

src/netgroup.h

src/netmessagemaker.h

src/node/chainstatemanager_args.cpp

src/node/connection_types.h

src/node/context.h

src/node/interface_ui.h

src/node/mempool_args.cpp

src/node/mining_args.cpp

src/node/minisketchwrapper.cpp

src/node/txreconciliation.h

src/policy/fees/estimator_args.cpp

src/policy/fees/estimator_args.h

src/policy/fees/estimator_man.cpp

src/policy/fees/estimator_man.h

src/policy/packages.h

src/policy/rbf.h

src/policy/truc_policy.h

src/pow.h

src/primitives/block.cpp

src/randomenv.h

src/rest.h

src/script/keyorigin.h

src/script/parsing.cpp

src/script/parsing.h

src/script/script_error.h

src/script/sigcache.cpp

src/script/sigcache.h

src/script/solver.h

src/script/verify_flags.h

src/semaphore_grant.h

src/signet.h

src/span.h

src/support/allocators/secure.h

src/support/allocators/zeroafterfree.h

src/util/tokenpipe.cpp

src/util/translation.h

src/util/vector.h

src/versionbits.h

src/versionbits_impl.h

src/wallet/external_signer_scriptpubkeyman.h

src/wallet/fees.h

src/wallet/load.h

src/wallet/receive.h

src/wallet/rpc/wallet.h

src/wallet/types.h

src/walletinitinterface.h

src/zmq/zmqabstractnotifier.cpp

Independent explanations by MyBitcoinExplorer. Not affiliated with or endorsed by Bitcoin Core. Guides are educational and do not replace the source or its tests.

Bitcoin Core source © its contributors, distributed under the MIT license. Original notices and bundled third-party licenses are retained in the source tree.