Constructing the parameters for each Bitcoin network

251        consensus.BIP65Height = 581885; // 00000000007f6655f22f98e72ed80d8b06dc761d5da09df0fa1dc4be4f861eb6
252        consensus.BIP66Height = 330776; // 000000002104c8c45e99a8853285a3b592602a3ccde2b832481da85e9e4ba182
253        consensus.CSVHeight = 770112; // 00000000025e930139bac5c6c31a403776da130831ab85be56578f3fa75369bb
254        consensus.SegwitHeight = 834624; // 00000000002b980fcd729daaa248fd9316a5200e9b367f4ff2c42453e84201ca
255        consensus.MinBIP9WarningHeight = 2013984; // taproot activation height + miner confirmation window
256        consensus.powLimit = uint256{"00000000ffffffffffffffffffffffffffffffffffffffffffffffffffffffff"};
257        consensus.nPowTargetTimespan = 14 * 24 * 60 * 60; // two weeks
258        consensus.nPowTargetSpacing = 10 * 60;
259        consensus.fPowAllowMinDifficultyBlocks = true;
260        consensus.enforce_BIP94 = false;
261        consensus.fPowNoRetargeting = false;
262        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].bit = 28;
263        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = Consensus::BIP9Deployment::NEVER_ACTIVE;
264        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
265        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].min_activation_height = 0; // No activation delay
266        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].threshold = 1512; // 75%
267        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].period = 2016;
268
269        ApplyDeploymentOptions(opts.dep_opts);
270
271        consensus.nMinimumChainWork = uint256{"0000000000000000000000000000000000000000000017f49f702147f10c0eb6"};
272        consensus.defaultAssumeValid = uint256{"00000000b318a3703d14a844c55ef507f4c2fc8f8766e24271fd43c180c51637"}; // 5128859
273
274        pchMessageStart[0] = 0x0b;
275        pchMessageStart[1] = 0x11;
276        pchMessageStart[2] = 0x09;
277        pchMessageStart[3] = 0x07;
278        nDefaultPort = 18333;
279        nPruneAfterHeight = 1000;
280        m_assumed_blockchain_size = 245;
281        m_assumed_chain_state_size = 19;
282
283        genesis = CreateGenesisBlock(1296688602, 414098458, 0x1d00ffff, 1, 50 * COIN);
284        consensus.hashGenesisBlock = genesis.GetHash();
285        assert(consensus.hashGenesisBlock == uint256{"000000000933ea01ad0ee984209779baaec3ced90fa3f408719526f8d77f4943"});
286        assert(genesis.hashMerkleRoot == uint256{"4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b"});
287
288        vFixedSeeds.clear();
289        vSeeds.clear();
290        // nodes with support for servicebits filtering should be at the top
291        vSeeds.emplace_back("testnet-seed.bitcoin.jonasschnelli.ch.");
292        vSeeds.emplace_back("seed.tbtc.petertodd.net.");
293        vSeeds.emplace_back("testnet-seed.bluematt.me."); // Just a static list of stable node(s), only supports x9
294        vSeeds.emplace_back("seed.testnet.achownodes.xyz."); // Ava Chow, only supports x1, x5, x9, x49, x809, x849, xd, x400, x404, x408, x448, xc08, xc48, x40c
295
296        base58Prefixes[PUBKEY_ADDRESS] = std::vector<unsigned char>(1,111);
297        base58Prefixes[SCRIPT_ADDRESS] = std::vector<unsigned char>(1,196);
298        base58Prefixes[SECRET_KEY] =     std::vector<unsigned char>(1,239);
299        base58Prefixes[EXT_PUBLIC_KEY] = {0x04, 0x35, 0x87, 0xCF};
300        base58Prefixes[EXT_SECRET_KEY] = {0x04, 0x35, 0x83, 0x94};
301
302        bech32_hrp = "tb";
303
304        vFixedSeeds = std::vector<uint8_t>(std::begin(chainparams_seed_test), std::end(chainparams_seed_test));
305
306        fDefaultConsistencyChecks = false;
307        m_is_mockable_chain = false;
308
309        m_assumeutxo_data = {
310            {
311                .height = 2'500'000,
312                .hash_serialized = AssumeutxoHash{uint256{"f841584909f68e47897952345234e37fcd9128cd818f41ee6c3ca68db8071be7"}},
313                .m_chain_tx_count = 66484552,
314                .blockhash = uint256{"0000000000000093bcb68c03a9a168ae252572d348a2eaeba2cdf9231d73206f"},
315            },
316            {
317                .height = 4'840'000,
318                .hash_serialized = AssumeutxoHash{uint256{"ce6bb677bb2ee9789c4a1c9d73e6683c53fc20e8fdbedbdaaf468982a0c8db2a"}},
319                .m_chain_tx_count = 536078574,
320                .blockhash = uint256{"00000000000000f4971a7fb37fbdff89315b69a2e1920c467654a382f0d64786"},
321            },
322            {
323                .height = 5'125'000,
324                .hash_serialized = AssumeutxoHash{uint256{"d05430f34c9b7dd7eb98c0718cdf03782bcce8273847557d68ac2efc1365d4b8"}},
325                .m_chain_tx_count = 536708663,
326                .blockhash = uint256{"00000000000009ad1946e21cb4f1a6323ee99c89017b59d5166472672b868133"},
327            }
328        };
329
330        chainTxData = ChainTxData{
331            // Data from RPC: getchaintxstats 4096 00000000b318a3703d14a844c55ef507f4c2fc8f8766e24271fd43c180c51637
332            .nTime    = 1788932318,
333            .tx_count = 536748780,
334            .dTxRate  = 0.02306697351149596,
335        };
336
337        // Generated by headerssync-params.py on 2026-09-08.
338        m_headers_sync_params = HeadersSyncParams{
339            .commitment_period = 682,
340            .redownload_buffer_size = 14613, // 14613/682 = ~21.4 commitments
341        };
342    }
343};
344
345/**
346 * Testnet (v4): public test network which is reset from time to time.
347 */
348class CTestNet4Params : public CChainParams {
349public:
350    CTestNet4Params(const TestNetOptions& opts) {
351        m_chain_type = ChainType::TESTNET4;
352        consensus.signet_blocks = false;
353        consensus.signet_challenge.clear();
354        consensus.nSubsidyHalvingInterval = 210000;
355        consensus.BIP34Height = 1;
356        consensus.BIP34Hash = uint256{};
357        consensus.BIP65Height = 1;
358        consensus.BIP66Height = 1;
359        consensus.CSVHeight = 1;
360        consensus.SegwitHeight = 1;
361        consensus.MinBIP9WarningHeight = 0;
362        consensus.powLimit = uint256{"00000000ffffffffffffffffffffffffffffffffffffffffffffffffffffffff"};
363        consensus.nPowTargetTimespan = 14 * 24 * 60 * 60; // two weeks
364        consensus.nPowTargetSpacing = 10 * 60;
365        consensus.fPowAllowMinDifficultyBlocks = true;
366        consensus.enforce_BIP94 = true;
367        consensus.fPowNoRetargeting = false;
368
369        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].bit = 28;
370        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = Consensus::BIP9Deployment::NEVER_ACTIVE;
371        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
372        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].min_activation_height = 0; // No activation delay
373        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].threshold = 1512; // 75%
374        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].period = 2016;
375
376        ApplyDeploymentOptions(opts.dep_opts);
377
378        consensus.nMinimumChainWork = uint256{"000000000000000000000000000000000000000000000e346a558455ade8eca9"};
379        consensus.defaultAssumeValid = uint256{"0000000021df65b91665a342e26ceb05e54826ad7d8fcd40316230058fa3b865"}; // 151604
380
381        pchMessageStart[0] = 0x1c;
382        pchMessageStart[1] = 0x16;
383        pchMessageStart[2] = 0x3f;
384        pchMessageStart[3] = 0x28;
385        nDefaultPort = 48333;
386        nPruneAfterHeight = 1000;
387        m_assumed_blockchain_size = 31;
388        m_assumed_chain_state_size = 2;
389
390        const char* testnet4_genesis_msg = "03/May/2024 000000000000000000001ebd58c244970b3aa9d783bb001011fbe8ea8e98e00e";
391        const CScript testnet4_genesis_script = CScript() << "000000000000000000000000000000000000000000000000000000000000000000"_hex << OP_CHECKSIG;
392        genesis = CreateGenesisBlock(testnet4_genesis_msg,
393                testnet4_genesis_script,
394                1714777860,
395                393743547,
396                0x1d00ffff,
397                1,
398                50 * COIN);
399        consensus.hashGenesisBlock = genesis.GetHash();
400        assert(consensus.hashGenesisBlock == uint256{"00000000da84f2bafbbc53dee25a72ae507ff4914b867c565be350b0da8bf043"});
401        assert(genesis.hashMerkleRoot == uint256{"7aa0a7ae1e223414cb807e40cd57e667b718e42aaf9306db9102fe28912b7b4e"});
402
403        vFixedSeeds.clear();
404        vSeeds.clear();
405        // nodes with support for servicebits filtering should be at the top
406        vSeeds.emplace_back("seed.testnet4.bitcoin.sprovoost.nl."); // Sjors Provoost
407        vSeeds.emplace_back("seed.testnet4.wiz.biz."); // Jason Maurice
408
409        base58Prefixes[PUBKEY_ADDRESS] = std::vector<unsigned char>(1,111);
410        base58Prefixes[SCRIPT_ADDRESS] = std::vector<unsigned char>(1,196);
411        base58Prefixes[SECRET_KEY] =     std::vector<unsigned char>(1,239);
412        base58Prefixes[EXT_PUBLIC_KEY] = {0x04, 0x35, 0x87, 0xCF};
413        base58Prefixes[EXT_SECRET_KEY] = {0x04, 0x35, 0x83, 0x94};
414
415        bech32_hrp = "tb";
416
417        vFixedSeeds = std::vector<uint8_t>(std::begin(chainparams_seed_testnet4), std::end(chainparams_seed_testnet4));
418
419        fDefaultConsistencyChecks = false;
420        m_is_mockable_chain = false;
421
422        m_assumeutxo_data = {
423            {
424                .height = 90'000,
425                .hash_serialized = AssumeutxoHash{uint256{"784fb5e98241de66fdd429f4392155c9e7db5c017148e66e8fdbc95746f8b9b5"}},
426                .m_chain_tx_count = 11347043,
427                .blockhash = uint256{"0000000002ebe8bcda020e0dd6ccfbdfac531d2f6a81457191b99fc2df2dbe3b"},
428            },
429            {
430                .height = 120'000,
431                .hash_serialized = AssumeutxoHash{uint256{"10b05d05ad468d0971162e1b222a4aa66caca89da2bb2a93f8f37fb29c4794b0"}},
432                .m_chain_tx_count = 14141057,
433                .blockhash = uint256{"000000000bd2317e51b3c5794981c35ba894ce27d3e772d5c39ecd9cbce01dc8"},
434            },
435            {
436                .height = 150'000,
437                .hash_serialized = AssumeutxoHash{uint256{"ca068cae50679d7c947454bbe4f0e6aeec1fbe2c6c2735a08bb988623649f950"}},
438                .m_chain_tx_count = 14810011,
439                .blockhash = uint256{"0000000000d9877342754dea8ec1eb24631517d38e3443c370465ee53a8b7434"},
440            }
441        };
442
443        chainTxData = ChainTxData{
444            // Data from RPC: getchaintxstats 4096 0000000021df65b91665a342e26ceb05e54826ad7d8fcd40316230058fa3b865
445            .nTime    = 1788932739,
446            .tx_count = 14825119,
447            .dTxRate  = 0.1148250171344748,
448        };
449
450        // Generated by headerssync-params.py on 2026-09-08.
451        m_headers_sync_params = HeadersSyncParams{
452            .commitment_period = 616,
453            .redownload_buffer_size = 16199, // 16199/616 = ~26.3 commitments
454        };
455    }
456};
457
458/**
459 * Signet: test network with an additional consensus parameter (see BIP325).
460 */
461class SigNetParams : public CChainParams {
462public:
463    explicit SigNetParams(const SigNetOptions& options)
464    {
465        std::vector<uint8_t> bin;
466        vFixedSeeds.clear();
467        vSeeds.clear();
468
469        if (!options.challenge) {
470            bin = "512103ad5e0edad18cb1f0fc0d28a3d4f1f3e445640337489abb10404f2d1e086be430210359ef5021964fe22d6f8e05b2463c9540ce96883fe3b278760f048f5189f2e6c452ae"_hex_v_u8;
471            vFixedSeeds = std::vector<uint8_t>(std::begin(chainparams_seed_signet), std::end(chainparams_seed_signet));
472            vSeeds.emplace_back("seed.signet.bitcoin.sprovoost.nl.");
473            vSeeds.emplace_back("seed.signet.achownodes.xyz."); // Ava Chow, only supports x1, x5, x9, x49, x809, x849, xd, x400, x404, x408, x448, xc08, xc48, x40c
474
475            consensus.nMinimumChainWork = uint256{"00000000000000000000000000000000000000000000000000001090e9dc1520"};
476            consensus.defaultAssumeValid = uint256{"00000002a5e0ba0498f1e9f4591af0b66b63c654665efe65206fd0ae7bbaf923"}; // 321295
477            m_assumed_blockchain_size = 25;
478            m_assumed_chain_state_size = 5;
479            chainTxData = ChainTxData{
480                // Data from RPC: getchaintxstats 4096 00000002a5e0ba0498f1e9f4591af0b66b63c654665efe65206fd0ae7bbaf923
481                .nTime    = 1788925860,
482                .tx_count = 32273793,
483                .dTxRate  = 0.3977566114505673,
484            };
485        } else {
486            bin = *options.challenge;
487            consensus.nMinimumChainWork = uint256{};
488            consensus.defaultAssumeValid = uint256{};
489            m_assumed_blockchain_size = 0;
490            m_assumed_chain_state_size = 0;
491            chainTxData = ChainTxData{
492                0,
493                0,
494                0,
495            };
496            LogInfo("Signet with challenge %s", HexStr(bin));
497        }
498
499        if (options.seeds) {
500            vSeeds = *options.seeds;