Merge bitcoin#34677: kernel: Chainparams and headerssync updates pre-31.0

44538f8 kernel: Add recent assumeutxo snapshot info (Ava Chow)
58c2e23 kernel: Update headerssync params (Ava Chow)
cf261b0 kernel: update chainTxData (Ava Chow)
8eaf1d2 kernel: update defaultAssumeValid and minimumChainWork (Ava Chow)
5ca0c55 kernel: update assumed blockchain and chainstate sizes (Ava Chow)

Pull request description:

  Update chainparams and headerssync params per the release process.

  Also added new assumeutxo snapshots for each network. I've uploaded snapshots to https://achow101.com/files/utxo-snapshots/

ACKs for top commit:
  Sjors:
    ACK 44538f8
  fjahr:
    ACK 44538f8
  janb84:
    ACK 44538f8
  sipa:
    ACK 44538f8. I re-did all the mainnet parameters, but did not look closely at the other networks.
  jaonoctus:
    ACK 44538f8

Tree-SHA512: f9b6ccc967c5ef58f734245df459c3136491e9b6a0f6e36f4272bc0787e7b59eabe47a8c8b19a90267eca4a0b5851dfbf45153f96eac599c417f148b3cf264cf

Author: fanquake

contrib/devtools/headerssync-params.py

@@ -12,13 +12,13 @@
 # Parameters:
 
 # Aim for still working fine at some point in the future. [datetime]
-TIME = datetime(2028, 4, 2)
+TIME = datetime(2028, 10, 10)
 
 # Expected block interval. [timedelta]
 BLOCK_INTERVAL = timedelta(seconds=600)
 
 # The number of headers corresponding to the minchainwork parameter. [headers]
-MINCHAINWORK_HEADERS = 912683
+MINCHAINWORK_HEADERS = 938343
 
 # Combined processing bandwidth from all attackers to one victim. [bit/s]
 # 6 Gbit/s is approximately the speed at which a single thread of a Ryzen 5950X CPU thread can hash

src/kernel/chainparams.cpp

@@ -114,8 +114,8 @@ class CMainParams : public CChainParams {
         consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].threshold = 1815; // 90%
         consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].period = 2016;
 
-        consensus.nMinimumChainWork = uint256{"0000000000000000000000000000000000000000dee8e2a309ad8a9820433c68"};
-        consensus.defaultAssumeValid = uint256{"00000000000000000000611fd22f2df7c8fbd0688745c3a6c3bb5109cc2a12cb"}; // 912683
+        consensus.nMinimumChainWork = uint256{"0000000000000000000000000000000000000001128750f82f4c366153a3a030"};
+        consensus.defaultAssumeValid = uint256{"00000000000000000000ccebd6d74d9194d8dcdc1d177c478e094bfad51ba5ac"}; // 938343
 
         /**
          * The message start string is designed to be unlikely to occur in normal data.
@@ -128,7 +128,7 @@ class CMainParams : public CChainParams {
         pchMessageStart[3] = 0xd9;
         nDefaultPort = 8333;
         nPruneAfterHeight = 100000;
-        m_assumed_blockchain_size = 810;
+        m_assumed_blockchain_size = 856;
         m_assumed_chain_state_size = 14;
 
         genesis = CreateGenesisBlock(1231006505, 2083236893, 0x1d00ffff, 1, 50 * COIN);
@@ -181,20 +181,26 @@ class CMainParams : public CChainParams {
                 .hash_serialized = AssumeutxoHash{uint256{"4daf8a17b4902498c5787966a2b51c613acdab5df5db73f196fa59a4da2f1568"}},
                 .m_chain_tx_count = 1226586151,
                 .blockhash = uint256{"0000000000000000000108970acb9522ffd516eae17acddcb1bd16469194a821"},
+            },
+            {
+                .height = 935'000,
+                .hash_serialized = AssumeutxoHash{uint256{"e4b90ef9eae834f56c4b64d2d50143cee10ad87994c614d7d04125e2a6025050"}},
+                .m_chain_tx_count = 1305397408,
+                .blockhash = uint256{"0000000000000000000147034958af1652b2b91bba607beacc5e72a56f0fb5ee"},
             }
         };
 
         chainTxData = ChainTxData{
-            // Data from RPC: getchaintxstats 4096 00000000000000000000611fd22f2df7c8fbd0688745c3a6c3bb5109cc2a12cb
-            .nTime    = 1756722903,
-            .tx_count = 1235299397,
-            .dTxRate  = 5.456290459519495,
+            // Data from RPC: getchaintxstats 4096 00000000000000000000ccebd6d74d9194d8dcdc1d177c478e094bfad51ba5ac
+            .nTime    = 1772055173,
+            .tx_count = 1315805869,
+            .dTxRate  = 5.40111006496122,
         };
 
-        // Generated by headerssync-params.py on 2025-09-01.
+        // Generated by headerssync-params.py on 2026-02-25.
         m_headers_sync_params = HeadersSyncParams{
-            .commitment_period = 632,
-            .redownload_buffer_size = 15009, // 15009/632 = ~23.7 commitments
+            .commitment_period = 641,
+            .redownload_buffer_size = 15218, // 15218/641 = ~23.7 commitments
         };
     }
 };
@@ -239,16 +245,16 @@ class CTestNetParams : public CChainParams {
         consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].threshold = 1512; // 75%
         consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].period = 2016;
 
-        consensus.nMinimumChainWork = uint256{"0000000000000000000000000000000000000000000016dd270dd94fac1d7632"};
-        consensus.defaultAssumeValid = uint256{"0000000000000065c6c38258e201971a3fdfcc2ceee0dd6e85a6c022d45dee34"}; // 4550000
+        consensus.nMinimumChainWork = uint256{"0000000000000000000000000000000000000000000017dde1c649f3708d14b6"};
+        consensus.defaultAssumeValid = uint256{"000000007a61e4230b28ac5cb6b5e5a0130de37ac1faf2f8987d2fa6505b67f4"}; // 4842348
 
         pchMessageStart[0] = 0x0b;
         pchMessageStart[1] = 0x11;
         pchMessageStart[2] = 0x09;
         pchMessageStart[3] = 0x07;
         nDefaultPort = 18333;
         nPruneAfterHeight = 1000;
-        m_assumed_blockchain_size = 240;
+        m_assumed_blockchain_size = 245;
         m_assumed_chain_state_size = 19;
 
         genesis = CreateGenesisBlock(1296688602, 414098458, 0x1d00ffff, 1, 50 * COIN);
@@ -284,20 +290,26 @@ class CTestNetParams : public CChainParams {
                 .hash_serialized = AssumeutxoHash{uint256{"f841584909f68e47897952345234e37fcd9128cd818f41ee6c3ca68db8071be7"}},
                 .m_chain_tx_count = 66484552,
                 .blockhash = uint256{"0000000000000093bcb68c03a9a168ae252572d348a2eaeba2cdf9231d73206f"},
+            },
+            {
+                .height = 4'840'000,
+                .hash_serialized = AssumeutxoHash{uint256{"ce6bb677bb2ee9789c4a1c9d73e6683c53fc20e8fdbedbdaaf468982a0c8db2a"}},
+                .m_chain_tx_count = 536078574,
+                .blockhash = uint256{"00000000000000f4971a7fb37fbdff89315b69a2e1920c467654a382f0d64786"},
             }
         };
 
         chainTxData = ChainTxData{
-            // Data from RPC: getchaintxstats 4096 0000000000000065c6c38258e201971a3fdfcc2ceee0dd6e85a6c022d45dee34
-            .nTime    = 1751816758,
-            .tx_count = 508468699,
-            .dTxRate  = 7.172978845985714,
+            // Data from RPC: getchaintxstats 4096 000000007a61e4230b28ac5cb6b5e5a0130de37ac1faf2f8987d2fa6505b67f4
+            .nTime    = 1772051651,
+            .tx_count = 536108416,
+            .dTxRate  = 0.02691479016257117,
         };
 
-        // Generated by headerssync-params.py on 2025-09-03.
+        // Generated by headerssync-params.py on 2026-02-25.
         m_headers_sync_params = HeadersSyncParams{
-            .commitment_period = 628,
-            .redownload_buffer_size = 13460, // 13460/628 = ~21.4 commitments
+            .commitment_period = 673,
+            .redownload_buffer_size = 14460, // 14460/673 = ~21.5 commitments
         };
     }
 };
@@ -341,16 +353,16 @@ class CTestNet4Params : public CChainParams {
         consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].threshold = 1512; // 75%
         consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].period = 2016;
 
-        consensus.nMinimumChainWork = uint256{"00000000000000000000000000000000000000000000034a4690fe592dc49c7c"};
-        consensus.defaultAssumeValid = uint256{"000000000000000180a58e7fa3b0db84b5ea76377524894f53660d93ac839d9b"}; // 91000
+        consensus.nMinimumChainWork = uint256{"0000000000000000000000000000000000000000000009a0fe15d0177d086304"};
+        consensus.defaultAssumeValid = uint256{"0000000002368b1e4ee27e2e85676ae6f9f9e69579b29093e9a82c170bf7cf8a"}; // 123613
 
         pchMessageStart[0] = 0x1c;
         pchMessageStart[1] = 0x16;
         pchMessageStart[2] = 0x3f;
         pchMessageStart[3] = 0x28;
         nDefaultPort = 48333;
         nPruneAfterHeight = 1000;
-        m_assumed_blockchain_size = 22;
+        m_assumed_blockchain_size = 31;
         m_assumed_chain_state_size = 2;
 
         const char* testnet4_genesis_msg = "03/May/2024 000000000000000000001ebd58c244970b3aa9d783bb001011fbe8ea8e98e00e";
@@ -391,20 +403,26 @@ class CTestNet4Params : public CChainParams {
                 .hash_serialized = AssumeutxoHash{uint256{"784fb5e98241de66fdd429f4392155c9e7db5c017148e66e8fdbc95746f8b9b5"}},
                 .m_chain_tx_count = 11347043,
                 .blockhash = uint256{"0000000002ebe8bcda020e0dd6ccfbdfac531d2f6a81457191b99fc2df2dbe3b"},
+            },
+            {
+                .height = 120'000,
+                .hash_serialized = AssumeutxoHash{uint256{"10b05d05ad468d0971162e1b222a4aa66caca89da2bb2a93f8f37fb29c4794b0"}},
+                .m_chain_tx_count = 14141057,
+                .blockhash = uint256{"000000000bd2317e51b3c5794981c35ba894ce27d3e772d5c39ecd9cbce01dc8"},
             }
         };
 
         chainTxData = ChainTxData{
-            // Data from RPC: getchaintxstats 4096 000000000000000180a58e7fa3b0db84b5ea76377524894f53660d93ac839d9b
-            .nTime    = 1752470331,
-            .tx_count = 11414302,
-            .dTxRate  = 0.2842619757327476,
+            // Data from RPC: getchaintxstats 4096 0000000002368b1e4ee27e2e85676ae6f9f9e69579b29093e9a82c170bf7cf8a
+            .nTime    = 1772013387,
+            .tx_count = 14191421,
+            .dTxRate  = 0.01848579579528412,
         };
 
-        // Generated by headerssync-params.py on 2025-09-03.
+        // Generated by headerssync-params.py on 2026-02-25.
         m_headers_sync_params = HeadersSyncParams{
-            .commitment_period = 275,
-            .redownload_buffer_size = 7017, // 7017/275 = ~25.5 commitments
+            .commitment_period = 606,
+            .redownload_buffer_size = 16092, // 16092/606 = ~26.6 commitments
         };
     }
 };
@@ -426,15 +444,15 @@ class SigNetParams : public CChainParams {
             vSeeds.emplace_back("seed.signet.bitcoin.sprovoost.nl.");
             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
 
-            consensus.nMinimumChainWork = uint256{"0000000000000000000000000000000000000000000000000000067d328e681a"};
-            consensus.defaultAssumeValid = uint256{"000000128586e26813922680309f04e1de713c7542fee86ed908f56368aefe2e"}; // 267665
-            m_assumed_blockchain_size = 20;
+            consensus.nMinimumChainWork = uint256{"00000000000000000000000000000000000000000000000000000b463ea0a4b8"};
+            consensus.defaultAssumeValid = uint256{"00000008414aab61092ef93f1aacc54cf9e9f16af29ddad493b908a01ff5c329"}; // 293175
+            m_assumed_blockchain_size = 24;
             m_assumed_chain_state_size = 4;
             chainTxData = ChainTxData{
-                // Data from RPC: getchaintxstats 4096 000000128586e26813922680309f04e1de713c7542fee86ed908f56368aefe2e
-                .nTime    = 1756723017,
-                .tx_count = 26185472,
-                .dTxRate  = 0.7452721495389969,
+                // Data from RPC: getchaintxstats 4096 00000008414aab61092ef93f1aacc54cf9e9f16af29ddad493b908a01ff5c329
+                .nTime    = 1772055248,
+                .tx_count = 28676833,
+                .dTxRate  = 0.06736623436338929,
             };
         } else {
             bin = *options.challenge;
@@ -506,6 +524,12 @@ class SigNetParams : public CChainParams {
                 .hash_serialized = AssumeutxoHash{uint256{"fe0a44309b74d6b5883d246cb419c6221bcccf0b308c9b59b7d70783dbdf928a"}},
                 .m_chain_tx_count = 2289496,
                 .blockhash = uint256{"0000003ca3c99aff040f2563c2ad8f8ec88bd0fd6b8f0895cfaf1ef90353a62c"},
+            },
+            {
+                .height = 290'000,
+                .hash_serialized = AssumeutxoHash{uint256{"97267e000b4b876800167e71b9123f1529d13b14308abec2888bbd2160d14545"}},
+                .m_chain_tx_count = 28547497,
+                .blockhash = uint256{"0000000577f2741bb30cd9d39d6d71b023afbeb9764f6260786a97969d5c9ac0"},
             }
         };
 
@@ -520,10 +544,10 @@ class SigNetParams : public CChainParams {
         fDefaultConsistencyChecks = false;
         m_is_mockable_chain = false;
 
-        // Generated by headerssync-params.py on 2025-09-03.
+        // Generated by headerssync-params.py on 2026-02-25.
         m_headers_sync_params = HeadersSyncParams{
-            .commitment_period = 390,
-            .redownload_buffer_size = 9584, // 9584/390 = ~24.6 commitments
+            .commitment_period = 620,
+            .redownload_buffer_size = 15724, // 15724/620 = ~25.4 commitments
         };
     }
 };