1 // Copyright (c) 2012-2013 The PPCoin developers
2 // Copyright (c) 2013-2015 The Novacoin developers
3 // Distributed under the MIT/X11 software license, see the accompanying
4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
5 // Distributed under the MIT/X11 software license, see the accompanying
6 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
8 #include <boost/assign/list_of.hpp>
11 #include "kernel_worker.h"
12 #include "txdb-leveldb.h"
14 extern unsigned int nStakeMaxAge;
15 extern unsigned int nStakeTargetSpacing;
20 // Protocol switch time for fixed kernel modifier interval
21 unsigned int nModifierSwitchTime = 1413763200; // Mon, 20 Oct 2014 00:00:00 GMT
22 unsigned int nModifierTestSwitchTime = 1397520000; // Tue, 15 Apr 2014 00:00:00 GMT
24 // Note: user must upgrade before the protocol switch deadline, otherwise it's required to
25 // re-download the blockchain. The timestamp of upgrade is recorded in the blockchain
27 unsigned int nModifierUpgradeTime = 0;
29 typedef std::map<int, unsigned int> MapModifierCheckpoints;
31 // Hard checkpoints of stake modifiers to ensure they are deterministic
32 static std::map<int, unsigned int> mapStakeModifierCheckpoints =
33 boost::assign::map_list_of
35 ( 12661, 0x5d84115du )
36 (143990, 0x9c592c78u )
37 (149000, 0x48f2bdc4u )
38 (160000, 0x789df0f0u )
39 (200000, 0x01ec1503u )
40 (221047, 0x0b39ef50u )
41 (243100, 0xe928d83au )
42 (532000, 0x3e5c2b81u )
43 (561108, 0x9c1860b0u )
46 // Hard checkpoints of stake modifiers to ensure they are deterministic (testNet)
47 static std::map<int, unsigned int> mapStakeModifierCheckpointsTestNet =
48 boost::assign::map_list_of
52 // Pregenerated entropy bits table (from genesis to #9689)
54 // Bits are packed into array of 256 bit integers:
56 // * array index calculated as nHeight / 256
57 // * position of bit is calculated as nHeight & 0xFF.
59 const uint256 entropyStore[] = {
60 uint256("0x4555b4dcc1d690ddd9b810c90c66e82b18bf4f43cc887246c418383ec120a5ab"),
61 uint256("0xaa6d1198412fa77608addf6549c9198a22155e8afd7a9ded6179f6b7cfc66b0c"),
62 uint256("0x9442fabfa4116fb14a9769c2eea003845a1f5c3a0260f36b497d68f3a3cd4078"),
63 uint256("0x0e769042a9a98e42388195d699574b822d06515f7053ad884c53d7ee059f05b1"),
64 uint256("0x7005aac20baf70251aebfe3f1b95987d83ef1e3e6963de8fed601d4dd07bf7cf"),
65 uint256("0x58952c5c3de188f2e33c38d3f53d7bf44f9bc545a4289d266696273fa821be66"),
66 uint256("0x50b6c2ed780c08aaec3f7665b1b6004206243e3866456fc910b83b52d07eeb63"),
67 uint256("0x563841eefca85ba3384986c58100408ae3f1ba2ac727e1ac910ce154a06c702f"),
68 uint256("0x79275b03938b3e27a9b01a7f7953c6c487c58355f5d4169accfbb800213ffd13"),
69 uint256("0xd783f2538b3ed18f135af90adc687c5646d93aeaeaabc6667be94f7aa0a2d366"),
70 uint256("0xb441d0c175c40c8e88b09d88ea008af79cbed2d28219427d2e72fda682974db8"),
71 uint256("0x3204c43bd41f2e19628af3b0c9aca3db15bca4c8705d51056e7b17a319c04715"),
72 uint256("0x7e80e6ab7857d8f2f261a0a49c783bd800b365b8c9b85cc0e13f73904b0dcaa9"),
73 uint256("0xefaaee60ed82d2ad145c0e347941fdb131eb8fd289a45eef07121a93f283c5f1"),
74 uint256("0x3efc86e4334da332c1fd4c12513c40cff689f3efdc7f9913230822adacdda4f9"),
75 uint256("0xf0d6b8f38599a017fa35d1fbbf9ef51eca5ebc5b286aadba40c4c3e1d9bace0c"),
76 uint256("0x286a67f27323486036a0a92d35382fc8963c0c00bad331723318b4b9fdb2b56e"),
77 uint256("0xecbfaaa6567c54f08c4d5bd0118a2d7b58740f42cbfc73aa1536c1f5f76de87c"),
78 uint256("0xf9a4de1c5c46520de5aaf10d3796cf0e27ddce98b3398357f5726a949664e308"),
79 uint256("0xd75e6c4dc4be08401e3478d2467d9ab96a62af4f255c04a82c41af0de0a487bb"),
80 uint256("0x1a82c3bc6ad6047294c16571b5e2b7316c97bf8813e7da15798b9820d67e39f2"),
81 uint256("0xb49be0080de564e01829ded7e7971979565a741c5975dc9978dcc020192d396c"),
82 uint256("0x0d8eed113be67663b5a15a0625a9b49792b5ea59c005c4f405914877acab7000"),
83 uint256("0x8f9d46e2bc05a218ffa942965b747056197d393b097085523640cd59e07fe7c7"),
84 uint256("0x7a63ab40bc7f40ac2ebe9ede438d97b45fa6ed6f8419016da8d5f7a670111dda"),
85 uint256("0x63fbcc080448c43d6cf915c958314feff7a95a52ba43a68c05fc281d3a522d25"),
86 uint256("0xf834cf824c326d3ea861ea1e85dc3289265e37045981e28208e7344a7f8081d7"),
87 uint256("0xb4edc22ec98cc49b2f5af5bae3f52f5e6058280f74f2c432c2dd89ae49acceb8"),
88 uint256("0x0fe596037dcf81bf5c64f39755261c404ed088af5c8c31dd7549b6657ee92365"),
89 uint256("0xbbad51a0aeba254b01d18c328de9e932b9b859b61e622c325d64e2211b5e413d"),
90 uint256("0xabf0194cc787be938bc51c7fdf1cae4ec79e65ebab8fa8b8f40541c44ef384b0"),
91 uint256("0x83bc12d6fdbd3e854cb91c4ca7dfba3c38e8714121af88c8a8abdb33e5002438"),
92 uint256("0x71a2513026cabaedcbe55aeb6dc8049e5b763a3f54f10c33dd333624f764b38c"),
93 uint256("0xee6725632ff5c025dff6a18cd059875dcae20f399b03bccba13d9d5fcf6d9d9a"),
94 uint256("0xa168a2741d1e7e50cc74b79f695c25ffd3576e6bd61353c2a20e569fd63b2dac"),
95 uint256("0x6e462d2a87bfde9398b6747f94a8ed6a01e4d96c5b4372df5c910c106c48bd13"),
96 uint256("0x8eeb696181957c4b22434028990f49cb30006827c73860e77e2eecf5c38be99d"),
97 uint256("0x3188aaa65877b166f05cdc48f55b1f77a7d6fb221c395596d990ae5647e9ba96")
100 // Whether the given block is subject to new modifier protocol
101 bool IsFixedModifierInterval(unsigned int nTimeBlock)
103 return (nTimeBlock >= (fTestNet? nModifierTestSwitchTime : nModifierSwitchTime));
106 // Get the last stake modifier and its generation time from a given block
107 static bool GetLastStakeModifier(const CBlockIndex* pindex, uint64_t& nStakeModifier, int64_t& nModifierTime)
110 return error("GetLastStakeModifier: null pindex");
111 while (pindex && pindex->pprev && !pindex->GeneratedStakeModifier())
112 pindex = pindex->pprev;
113 if (!pindex->GeneratedStakeModifier())
114 return error("GetLastStakeModifier: no generation at genesis block");
115 nStakeModifier = pindex->nStakeModifier;
116 nModifierTime = pindex->GetBlockTime();
120 // Get selection interval section (in seconds)
121 static int64_t GetStakeModifierSelectionIntervalSection(int nSection)
123 assert (nSection >= 0 && nSection < 64);
124 return (nModifierInterval * 63 / (63 + ((63 - nSection) * (MODIFIER_INTERVAL_RATIO - 1))));
127 // Get stake modifier selection interval (in seconds)
128 static int64_t GetStakeModifierSelectionInterval()
130 int64_t nSelectionInterval = 0;
131 for (int nSection=0; nSection<64; nSection++)
132 nSelectionInterval += GetStakeModifierSelectionIntervalSection(nSection);
133 return nSelectionInterval;
136 // select a block from the candidate blocks in vSortedByTimestamp, excluding
137 // already selected blocks in vSelectedBlocks, and with timestamp up to
138 // nSelectionIntervalStop.
139 static bool SelectBlockFromCandidates(vector<pair<int64_t, uint256> >& vSortedByTimestamp, map<uint256, const CBlockIndex*>& mapSelectedBlocks,
140 int64_t nSelectionIntervalStop, uint64_t nStakeModifierPrev, const CBlockIndex** pindexSelected)
142 bool fSelected = false;
143 uint256 hashBest = 0;
144 *pindexSelected = (const CBlockIndex*) 0;
145 BOOST_FOREACH(const PAIRTYPE(int64_t, uint256)& item, vSortedByTimestamp)
147 if (!mapBlockIndex.count(item.second))
148 return error("SelectBlockFromCandidates: failed to find block index for candidate block %s", item.second.ToString().c_str());
149 const CBlockIndex* pindex = mapBlockIndex[item.second];
150 if (fSelected && pindex->GetBlockTime() > nSelectionIntervalStop)
152 if (mapSelectedBlocks.count(pindex->GetBlockHash()) > 0)
154 // compute the selection hash by hashing its proof-hash and the
155 // previous proof-of-stake modifier
156 uint256 hashProof = pindex->IsProofOfStake()? pindex->hashProofOfStake : pindex->GetBlockHash();
157 CDataStream ss(SER_GETHASH, 0);
158 ss << hashProof << nStakeModifierPrev;
159 uint256 hashSelection = Hash(ss.begin(), ss.end());
160 // the selection hash is divided by 2**32 so that proof-of-stake block
161 // is always favored over proof-of-work block. this is to preserve
162 // the energy efficiency property
163 if (pindex->IsProofOfStake())
164 hashSelection >>= 32;
165 if (fSelected && hashSelection < hashBest)
167 hashBest = hashSelection;
168 *pindexSelected = pindex;
173 hashBest = hashSelection;
174 *pindexSelected = pindex;
177 if (fDebug && GetBoolArg("-printstakemodifier"))
178 printf("SelectBlockFromCandidates: selection hash=%s\n", hashBest.ToString().c_str());
182 // Stake Modifier (hash modifier of proof-of-stake):
183 // The purpose of stake modifier is to prevent a txout (coin) owner from
184 // computing future proof-of-stake generated by this txout at the time
185 // of transaction confirmation. To meet kernel protocol, the txout
186 // must hash with a future stake modifier to generate the proof.
187 // Stake modifier consists of bits each of which is contributed from a
188 // selected block of a given block group in the past.
189 // The selection of a block is based on a hash of the block's proof-hash and
190 // the previous stake modifier.
191 // Stake modifier is recomputed at a fixed time interval instead of every
192 // block. This is to make it difficult for an attacker to gain control of
193 // additional bits in the stake modifier, even after generating a chain of
195 bool ComputeNextStakeModifier(const CBlockIndex* pindexCurrent, uint64_t& nStakeModifier, bool& fGeneratedStakeModifier)
198 fGeneratedStakeModifier = false;
199 const CBlockIndex* pindexPrev = pindexCurrent->pprev;
202 fGeneratedStakeModifier = true;
203 return true; // genesis block's modifier is 0
206 // First find current stake modifier and its generation block time
207 // if it's not old enough, return the same stake modifier
208 int64_t nModifierTime = 0;
209 if (!GetLastStakeModifier(pindexPrev, nStakeModifier, nModifierTime))
210 return error("ComputeNextStakeModifier: unable to get last modifier");
213 printf("ComputeNextStakeModifier: prev modifier=0x%016" PRIx64 " time=%s epoch=%u\n", nStakeModifier, DateTimeStrFormat(nModifierTime).c_str(), (unsigned int)nModifierTime);
215 if (nModifierTime / nModifierInterval >= pindexPrev->GetBlockTime() / nModifierInterval)
219 printf("ComputeNextStakeModifier: no new interval keep current modifier: pindexPrev nHeight=%d nTime=%u\n", pindexPrev->nHeight, (unsigned int)pindexPrev->GetBlockTime());
223 if (nModifierTime / nModifierInterval >= pindexCurrent->GetBlockTime() / nModifierInterval)
225 // fixed interval protocol requires current block timestamp also be in a different modifier interval
226 if (IsFixedModifierInterval(pindexCurrent->nTime))
230 printf("ComputeNextStakeModifier: no new interval keep current modifier: pindexCurrent nHeight=%d nTime=%u\n", pindexCurrent->nHeight, (unsigned int)pindexCurrent->GetBlockTime());
238 printf("ComputeNextStakeModifier: old modifier at block %s not meeting fixed modifier interval: pindexCurrent nHeight=%d nTime=%u\n", pindexCurrent->GetBlockHash().ToString().c_str(), pindexCurrent->nHeight, (unsigned int)pindexCurrent->GetBlockTime());
243 // Sort candidate blocks by timestamp
244 vector<pair<int64_t, uint256> > vSortedByTimestamp;
245 vSortedByTimestamp.reserve(64 * nModifierInterval / nStakeTargetSpacing);
246 int64_t nSelectionInterval = GetStakeModifierSelectionInterval();
247 int64_t nSelectionIntervalStart = (pindexPrev->GetBlockTime() / nModifierInterval) * nModifierInterval - nSelectionInterval;
248 const CBlockIndex* pindex = pindexPrev;
249 while (pindex && pindex->GetBlockTime() >= nSelectionIntervalStart)
251 vSortedByTimestamp.push_back(make_pair(pindex->GetBlockTime(), pindex->GetBlockHash()));
252 pindex = pindex->pprev;
254 int nHeightFirstCandidate = pindex ? (pindex->nHeight + 1) : 0;
255 reverse(vSortedByTimestamp.begin(), vSortedByTimestamp.end());
256 sort(vSortedByTimestamp.begin(), vSortedByTimestamp.end());
258 // Select 64 blocks from candidate blocks to generate stake modifier
259 uint64_t nStakeModifierNew = 0;
260 int64_t nSelectionIntervalStop = nSelectionIntervalStart;
261 map<uint256, const CBlockIndex*> mapSelectedBlocks;
262 for (int nRound=0; nRound<min(64, (int)vSortedByTimestamp.size()); nRound++)
264 // add an interval section to the current selection round
265 nSelectionIntervalStop += GetStakeModifierSelectionIntervalSection(nRound);
266 // select a block from the candidates of current round
267 if (!SelectBlockFromCandidates(vSortedByTimestamp, mapSelectedBlocks, nSelectionIntervalStop, nStakeModifier, &pindex))
268 return error("ComputeNextStakeModifier: unable to select block at round %d", nRound);
269 // write the entropy bit of the selected block
270 nStakeModifierNew |= (((uint64_t)pindex->GetStakeEntropyBit()) << nRound);
271 // add the selected block from candidates to selected list
272 mapSelectedBlocks.insert(make_pair(pindex->GetBlockHash(), pindex));
273 if (fDebug && GetBoolArg("-printstakemodifier"))
274 printf("ComputeNextStakeModifier: selected round %d stop=%s height=%d bit=%d\n", nRound, DateTimeStrFormat(nSelectionIntervalStop).c_str(), pindex->nHeight, pindex->GetStakeEntropyBit());
277 // Print selection map for visualization of the selected blocks
278 if (fDebug && GetBoolArg("-printstakemodifier"))
280 string strSelectionMap = "";
281 // '-' indicates proof-of-work blocks not selected
282 strSelectionMap.insert(0, pindexPrev->nHeight - nHeightFirstCandidate + 1, '-');
284 while (pindex && pindex->nHeight >= nHeightFirstCandidate)
286 // '=' indicates proof-of-stake blocks not selected
287 if (pindex->IsProofOfStake())
288 strSelectionMap.replace(pindex->nHeight - nHeightFirstCandidate, 1, "=");
289 pindex = pindex->pprev;
291 BOOST_FOREACH(const PAIRTYPE(uint256, const CBlockIndex*)& item, mapSelectedBlocks)
293 // 'S' indicates selected proof-of-stake blocks
294 // 'W' indicates selected proof-of-work blocks
295 strSelectionMap.replace(item.second->nHeight - nHeightFirstCandidate, 1, item.second->IsProofOfStake()? "S" : "W");
297 printf("ComputeNextStakeModifier: selection height [%d, %d] map %s\n", nHeightFirstCandidate, pindexPrev->nHeight, strSelectionMap.c_str());
301 printf("ComputeNextStakeModifier: new modifier=0x%016" PRIx64 " time=%s\n", nStakeModifierNew, DateTimeStrFormat(pindexPrev->GetBlockTime()).c_str());
304 nStakeModifier = nStakeModifierNew;
305 fGeneratedStakeModifier = true;
309 // The stake modifier used to hash for a stake kernel is chosen as the stake
310 // modifier about a selection interval later than the coin generating the kernel
311 static bool GetKernelStakeModifier(uint256 hashBlockFrom, uint64_t& nStakeModifier, int& nStakeModifierHeight, int64_t& nStakeModifierTime, bool fPrintProofOfStake)
314 if (!mapBlockIndex.count(hashBlockFrom))
315 return error("GetKernelStakeModifier() : block not indexed");
316 const CBlockIndex* pindexFrom = mapBlockIndex[hashBlockFrom];
317 nStakeModifierHeight = pindexFrom->nHeight;
318 nStakeModifierTime = pindexFrom->GetBlockTime();
319 int64_t nStakeModifierSelectionInterval = GetStakeModifierSelectionInterval();
320 const CBlockIndex* pindex = pindexFrom;
321 // loop to find the stake modifier later by a selection interval
322 while (nStakeModifierTime < pindexFrom->GetBlockTime() + nStakeModifierSelectionInterval)
325 { // reached best block; may happen if node is behind on block chain
326 if (fPrintProofOfStake || (pindex->GetBlockTime() + nStakeMinAge - nStakeModifierSelectionInterval > GetAdjustedTime()))
327 return error("GetKernelStakeModifier() : reached best block %s at height %d from block %s",
328 pindex->GetBlockHash().ToString().c_str(), pindex->nHeight, hashBlockFrom.ToString().c_str());
332 pindex = pindex->pnext;
333 if (pindex->GeneratedStakeModifier())
335 nStakeModifierHeight = pindex->nHeight;
336 nStakeModifierTime = pindex->GetBlockTime();
339 nStakeModifier = pindex->nStakeModifier;
343 bool GetKernelStakeModifier(uint256 hashBlockFrom, uint64_t& nStakeModifier)
345 int nStakeModifierHeight;
346 int64_t nStakeModifierTime;
348 return GetKernelStakeModifier(hashBlockFrom, nStakeModifier, nStakeModifierHeight, nStakeModifierTime, false);
352 // ppcoin kernel protocol
353 // coinstake must meet hash target according to the protocol:
354 // kernel (input 0) must meet the formula
355 // hash(nStakeModifier + txPrev.block.nTime + txPrev.offset + txPrev.nTime + txPrev.vout.n + nTime) < bnTarget * nCoinDayWeight
356 // this ensures that the chance of getting a coinstake is proportional to the
357 // amount of coin age one owns.
358 // The reason this hash is chosen is the following:
359 // nStakeModifier: scrambles computation to make it very difficult to precompute
360 // future proof-of-stake at the time of the coin's confirmation
361 // txPrev.block.nTime: prevent nodes from guessing a good timestamp to
362 // generate transaction for future advantage
363 // txPrev.offset: offset of txPrev inside block, to reduce the chance of
364 // nodes generating coinstake at the same time
365 // txPrev.nTime: reduce the chance of nodes generating coinstake at the same
367 // txPrev.vout.n: output number of txPrev, to reduce the chance of nodes
368 // generating coinstake at the same time
369 // block/tx hash should not be used here as they can be generated in vast
370 // quantities so as to generate blocks faster, degrading the system back into
371 // a proof-of-work situation.
373 bool CheckStakeKernelHash(uint32_t nBits, const CBlock& blockFrom, uint32_t nTxPrevOffset, const CTransaction& txPrev, const COutPoint& prevout, uint32_t nTimeTx, uint256& hashProofOfStake, uint256& targetProofOfStake, bool fPrintProofOfStake)
375 if (nTimeTx < txPrev.nTime) // Transaction timestamp violation
376 return error("CheckStakeKernelHash() : nTime violation");
378 uint32_t nTimeBlockFrom = blockFrom.GetBlockTime();
379 if (nTimeBlockFrom + nStakeMinAge > nTimeTx) // Min age requirement
380 return error("CheckStakeKernelHash() : min age violation");
382 CBigNum bnTargetPerCoinDay;
383 bnTargetPerCoinDay.SetCompact(nBits);
384 int64_t nValueIn = txPrev.vout[prevout.n].nValue;
386 uint256 hashBlockFrom = blockFrom.GetHash();
388 CBigNum bnCoinDayWeight = CBigNum(nValueIn) * GetWeight((int64_t)txPrev.nTime, (int64_t)nTimeTx) / COIN / nOneDay;
389 targetProofOfStake = (bnCoinDayWeight * bnTargetPerCoinDay).getuint256();
392 CDataStream ss(SER_GETHASH, 0);
393 uint64_t nStakeModifier = 0;
394 int nStakeModifierHeight = 0;
395 int64_t nStakeModifierTime = 0;
397 if (!GetKernelStakeModifier(hashBlockFrom, nStakeModifier, nStakeModifierHeight, nStakeModifierTime, fPrintProofOfStake))
399 ss << nStakeModifier;
401 ss << nTimeBlockFrom << nTxPrevOffset << txPrev.nTime << prevout.n << nTimeTx;
402 hashProofOfStake = Hash(ss.begin(), ss.end());
403 if (fPrintProofOfStake)
405 printf("CheckStakeKernelHash() : using modifier 0x%016" PRIx64 " at height=%d timestamp=%s for block from height=%d timestamp=%s\n",
406 nStakeModifier, nStakeModifierHeight,
407 DateTimeStrFormat(nStakeModifierTime).c_str(),
408 mapBlockIndex[hashBlockFrom]->nHeight,
409 DateTimeStrFormat(blockFrom.GetBlockTime()).c_str());
410 printf("CheckStakeKernelHash() : check modifier=0x%016" PRIx64 " nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashTarget=%s hashProof=%s\n",
412 nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx,
413 targetProofOfStake.ToString().c_str(), hashProofOfStake.ToString().c_str());
416 // Now check if proof-of-stake hash meets target protocol
417 if (CBigNum(hashProofOfStake) > bnCoinDayWeight * bnTargetPerCoinDay)
419 if (fDebug && !fPrintProofOfStake)
421 printf("CheckStakeKernelHash() : using modifier 0x%016" PRIx64 " at height=%d timestamp=%s for block from height=%d timestamp=%s\n",
422 nStakeModifier, nStakeModifierHeight,
423 DateTimeStrFormat(nStakeModifierTime).c_str(),
424 mapBlockIndex[hashBlockFrom]->nHeight,
425 DateTimeStrFormat(blockFrom.GetBlockTime()).c_str());
426 printf("CheckStakeKernelHash() : pass modifier=0x%016" PRIx64 " nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashTarget=%s hashProof=%s\n",
428 nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx,
429 targetProofOfStake.ToString().c_str(), hashProofOfStake.ToString().c_str());
434 // Scan given kernel for solution
435 bool ScanKernelForward(unsigned char *kernel, uint32_t nBits, uint32_t nInputTxTime, int64_t nValueIn, std::pair<uint32_t, uint32_t> &SearchInterval, std::vector<std::pair<uint256, uint32_t> > &solutions)
437 // TODO: custom threads amount
439 uint32_t nThreads = boost::thread::hardware_concurrency();
443 printf("Warning: hardware_concurrency() failed in %s:%d\n", __FILE__, __LINE__);
445 uint32_t nPart = (SearchInterval.second - SearchInterval.first) / nThreads;
447 KernelWorker *workers = new KernelWorker[nThreads];
449 boost::thread_group group;
450 for(size_t i = 0; i < nThreads; i++)
452 uint32_t nBegin = SearchInterval.first + nPart * i;
453 uint32_t nEnd = SearchInterval.first + nPart * (i + 1);
454 workers[i] = KernelWorker(kernel, nBits, nInputTxTime, nValueIn, nBegin, nEnd);
455 boost::function<void()> workerFnc = boost::bind(&KernelWorker::Do, &workers[i]);
456 group.create_thread(workerFnc);
462 for(size_t i = 0; i < nThreads; i++)
464 std::vector<std::pair<uint256, uint32_t> > ws = workers[i].GetSolutions();
465 solutions.insert(solutions.end(), ws.begin(), ws.end());
470 if (solutions.size() == 0)
479 // Check kernel hash target and coinstake signature
480 bool CheckProofOfStake(const CTransaction& tx, unsigned int nBits, uint256& hashProofOfStake, uint256& targetProofOfStake)
482 if (!tx.IsCoinStake())
483 return error("CheckProofOfStake() : called on non-coinstake %s", tx.GetHash().ToString().c_str());
485 // Kernel (input 0) must match the stake hash target per coin age (nBits)
486 const CTxIn& txin = tx.vin[0];
488 // First try finding the previous transaction in database
492 if (!txPrev.ReadFromDisk(txdb, txin.prevout, txindex))
493 return tx.DoS(1, error("CheckProofOfStake() : INFO: read txPrev failed")); // previous transaction not in main chain, may occur during initial download
496 if (!VerifySignature(txPrev, tx, 0, MANDATORY_SCRIPT_VERIFY_FLAGS, 0))
497 return tx.DoS(100, error("CheckProofOfStake() : VerifySignature failed on coinstake %s", tx.GetHash().ToString().c_str()));
501 if (!block.ReadFromDisk(txindex.pos.nFile, txindex.pos.nBlockPos, false))
502 return fDebug? error("CheckProofOfStake() : read block failed") : false; // unable to read block of previous transaction
504 if (!CheckStakeKernelHash(nBits, block, txindex.pos.nTxPos - txindex.pos.nBlockPos, txPrev, txin.prevout, tx.nTime, hashProofOfStake, targetProofOfStake, fDebug))
505 return tx.DoS(1, error("CheckProofOfStake() : INFO: check kernel failed on coinstake %s, hashProof=%s", tx.GetHash().ToString().c_str(), hashProofOfStake.ToString().c_str())); // may occur during initial download or if behind on block chain sync
510 // Get stake modifier checksum
511 uint32_t GetStakeModifierChecksum(const CBlockIndex* pindex)
513 assert (pindex->pprev || pindex->GetBlockHash() == (!fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet));
514 // Hash previous checksum with flags, hashProofOfStake and nStakeModifier
515 CDataStream ss(SER_GETHASH, 0);
517 ss << pindex->pprev->nStakeModifierChecksum;
518 ss << pindex->nFlags << pindex->hashProofOfStake << pindex->nStakeModifier;
519 uint256 hashChecksum = Hash(ss.begin(), ss.end());
520 hashChecksum >>= (256 - 32);
521 return static_cast<uint32_t>(hashChecksum.Get64());
524 // Check stake modifier hard checkpoints
525 bool CheckStakeModifierCheckpoints(int nHeight, uint32_t nStakeModifierChecksum)
527 MapModifierCheckpoints& checkpoints = (fTestNet ? mapStakeModifierCheckpointsTestNet : mapStakeModifierCheckpoints);
529 if (checkpoints.count(nHeight))
530 return nStakeModifierChecksum == checkpoints[nHeight];