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.
10 #include "kernel_worker.h"
11 #include "txdb-leveldb.h"
13 extern unsigned int nStakeTargetSpacing;
18 // Protocol switch time for fixed kernel modifier interval
19 unsigned int nModifierSwitchTime = 1413763200; // Mon, 20 Oct 2014 00:00:00 GMT
20 unsigned int nModifierTestSwitchTime = 1397520000; // Tue, 15 Apr 2014 00:00:00 GMT
22 // Note: user must upgrade before the protocol switch deadline, otherwise it's required to
23 // re-download the blockchain. The timestamp of upgrade is recorded in the blockchain
25 unsigned int nModifierUpgradeTime = 0;
27 typedef std::map<int, unsigned int> MapModifierCheckpoints;
29 // Hard checkpoints of stake modifiers to ensure they are deterministic
30 static std::map<int, unsigned int> mapStakeModifierCheckpoints =
33 { 12661, 0x5d84115du },
34 {143990, 0x9c592c78u },
35 {149000, 0x48f2bdc4u },
36 {160000, 0x789df0f0u },
37 {200000, 0x01ec1503u },
38 {221047, 0x0b39ef50u },
39 {243100, 0xe928d83au },
40 {532000, 0x3e5c2b81u },
41 {561108, 0x9c1860b0u },
42 {712891, 0xee193895u }
45 // Hard checkpoints of stake modifiers to ensure they are deterministic (testNet)
46 static std::map<int, unsigned int> mapStakeModifierCheckpointsTestNet =
51 // Pregenerated entropy bits table (from genesis to #9689)
53 // Bits are packed into array of 256 bit integers:
55 // * array index calculated as nHeight / 256
56 // * position of bit is calculated as nHeight & 0xFF.
58 const uint256 entropyStore[] = {
59 uint256("0x4555b4dcc1d690ddd9b810c90c66e82b18bf4f43cc887246c418383ec120a5ab"),
60 uint256("0xaa6d1198412fa77608addf6549c9198a22155e8afd7a9ded6179f6b7cfc66b0c"),
61 uint256("0x9442fabfa4116fb14a9769c2eea003845a1f5c3a0260f36b497d68f3a3cd4078"),
62 uint256("0x0e769042a9a98e42388195d699574b822d06515f7053ad884c53d7ee059f05b1"),
63 uint256("0x7005aac20baf70251aebfe3f1b95987d83ef1e3e6963de8fed601d4dd07bf7cf"),
64 uint256("0x58952c5c3de188f2e33c38d3f53d7bf44f9bc545a4289d266696273fa821be66"),
65 uint256("0x50b6c2ed780c08aaec3f7665b1b6004206243e3866456fc910b83b52d07eeb63"),
66 uint256("0x563841eefca85ba3384986c58100408ae3f1ba2ac727e1ac910ce154a06c702f"),
67 uint256("0x79275b03938b3e27a9b01a7f7953c6c487c58355f5d4169accfbb800213ffd13"),
68 uint256("0xd783f2538b3ed18f135af90adc687c5646d93aeaeaabc6667be94f7aa0a2d366"),
69 uint256("0xb441d0c175c40c8e88b09d88ea008af79cbed2d28219427d2e72fda682974db8"),
70 uint256("0x3204c43bd41f2e19628af3b0c9aca3db15bca4c8705d51056e7b17a319c04715"),
71 uint256("0x7e80e6ab7857d8f2f261a0a49c783bd800b365b8c9b85cc0e13f73904b0dcaa9"),
72 uint256("0xefaaee60ed82d2ad145c0e347941fdb131eb8fd289a45eef07121a93f283c5f1"),
73 uint256("0x3efc86e4334da332c1fd4c12513c40cff689f3efdc7f9913230822adacdda4f9"),
74 uint256("0xf0d6b8f38599a017fa35d1fbbf9ef51eca5ebc5b286aadba40c4c3e1d9bace0c"),
75 uint256("0x286a67f27323486036a0a92d35382fc8963c0c00bad331723318b4b9fdb2b56e"),
76 uint256("0xecbfaaa6567c54f08c4d5bd0118a2d7b58740f42cbfc73aa1536c1f5f76de87c"),
77 uint256("0xf9a4de1c5c46520de5aaf10d3796cf0e27ddce98b3398357f5726a949664e308"),
78 uint256("0xd75e6c4dc4be08401e3478d2467d9ab96a62af4f255c04a82c41af0de0a487bb"),
79 uint256("0x1a82c3bc6ad6047294c16571b5e2b7316c97bf8813e7da15798b9820d67e39f2"),
80 uint256("0xb49be0080de564e01829ded7e7971979565a741c5975dc9978dcc020192d396c"),
81 uint256("0x0d8eed113be67663b5a15a0625a9b49792b5ea59c005c4f405914877acab7000"),
82 uint256("0x8f9d46e2bc05a218ffa942965b747056197d393b097085523640cd59e07fe7c7"),
83 uint256("0x7a63ab40bc7f40ac2ebe9ede438d97b45fa6ed6f8419016da8d5f7a670111dda"),
84 uint256("0x63fbcc080448c43d6cf915c958314feff7a95a52ba43a68c05fc281d3a522d25"),
85 uint256("0xf834cf824c326d3ea861ea1e85dc3289265e37045981e28208e7344a7f8081d7"),
86 uint256("0xb4edc22ec98cc49b2f5af5bae3f52f5e6058280f74f2c432c2dd89ae49acceb8"),
87 uint256("0x0fe596037dcf81bf5c64f39755261c404ed088af5c8c31dd7549b6657ee92365"),
88 uint256("0xbbad51a0aeba254b01d18c328de9e932b9b859b61e622c325d64e2211b5e413d"),
89 uint256("0xabf0194cc787be938bc51c7fdf1cae4ec79e65ebab8fa8b8f40541c44ef384b0"),
90 uint256("0x83bc12d6fdbd3e854cb91c4ca7dfba3c38e8714121af88c8a8abdb33e5002438"),
91 uint256("0x71a2513026cabaedcbe55aeb6dc8049e5b763a3f54f10c33dd333624f764b38c"),
92 uint256("0xee6725632ff5c025dff6a18cd059875dcae20f399b03bccba13d9d5fcf6d9d9a"),
93 uint256("0xa168a2741d1e7e50cc74b79f695c25ffd3576e6bd61353c2a20e569fd63b2dac"),
94 uint256("0x6e462d2a87bfde9398b6747f94a8ed6a01e4d96c5b4372df5c910c106c48bd13"),
95 uint256("0x8eeb696181957c4b22434028990f49cb30006827c73860e77e2eecf5c38be99d"),
96 uint256("0x3188aaa65877b166f05cdc48f55b1f77a7d6fb221c395596d990ae5647e9ba96")
99 // Whether the given block is subject to new modifier protocol
100 bool IsFixedModifierInterval(unsigned int nTimeBlock)
102 return (nTimeBlock >= (fTestNet? nModifierTestSwitchTime : nModifierSwitchTime));
105 // Get the last stake modifier and its generation time from a given block
106 static bool GetLastStakeModifier(const CBlockIndex* pindex, uint64_t& nStakeModifier, int64_t& nModifierTime)
109 return error("GetLastStakeModifier: null pindex");
110 while (pindex && pindex->pprev && !pindex->GeneratedStakeModifier())
111 pindex = pindex->pprev;
112 if (!pindex->GeneratedStakeModifier())
113 return error("GetLastStakeModifier: no generation at genesis block");
114 nStakeModifier = pindex->nStakeModifier;
115 nModifierTime = pindex->GetBlockTime();
119 // Get selection interval section (in seconds)
120 static int64_t GetStakeModifierSelectionIntervalSection(int nSection)
122 assert (nSection >= 0 && nSection < 64);
123 return (nModifierInterval * 63 / (63 + ((63 - nSection) * (MODIFIER_INTERVAL_RATIO - 1))));
126 // Get stake modifier selection interval (in seconds)
127 static int64_t GetStakeModifierSelectionInterval()
129 int64_t nSelectionInterval = 0;
130 for (int nSection=0; nSection<64; nSection++)
131 nSelectionInterval += GetStakeModifierSelectionIntervalSection(nSection);
132 return nSelectionInterval;
135 // select a block from the candidate blocks in vSortedByTimestamp, excluding
136 // already selected blocks in vSelectedBlocks, and with timestamp up to
137 // nSelectionIntervalStop.
138 static bool SelectBlockFromCandidates(vector<pair<int64_t, uint256> >& vSortedByTimestamp, map<uint256, const CBlockIndex*>& mapSelectedBlocks,
139 int64_t nSelectionIntervalStop, uint64_t nStakeModifierPrev, const CBlockIndex** pindexSelected)
141 bool fSelected = false;
142 uint256 hashBest = 0;
143 *pindexSelected = (const CBlockIndex*) 0;
144 for (const auto& item : vSortedByTimestamp)
146 if (!mapBlockIndex.count(item.second))
147 return error("SelectBlockFromCandidates: failed to find block index for candidate block %s", item.second.ToString().c_str());
148 const CBlockIndex* pindex = mapBlockIndex[item.second];
149 if (fSelected && pindex->GetBlockTime() > nSelectionIntervalStop)
151 if (mapSelectedBlocks.count(pindex->GetBlockHash()) > 0)
153 // compute the selection hash by hashing its proof-hash and the
154 // previous proof-of-stake modifier
155 uint256 hashProof = pindex->IsProofOfStake()? pindex->hashProofOfStake : pindex->GetBlockHash();
156 CDataStream ss(SER_GETHASH, 0);
157 ss << hashProof << nStakeModifierPrev;
158 uint256 hashSelection = Hash(ss.begin(), ss.end());
159 // the selection hash is divided by 2**32 so that proof-of-stake block
160 // is always favored over proof-of-work block. this is to preserve
161 // the energy efficiency property
162 if (pindex->IsProofOfStake())
163 hashSelection >>= 32;
164 if (fSelected && hashSelection < hashBest)
166 hashBest = hashSelection;
167 *pindexSelected = pindex;
172 hashBest = hashSelection;
173 *pindexSelected = pindex;
176 if (fDebug && GetBoolArg("-printstakemodifier"))
177 printf("SelectBlockFromCandidates: selection hash=%s\n", hashBest.ToString().c_str());
181 // Stake Modifier (hash modifier of proof-of-stake):
182 // The purpose of stake modifier is to prevent a txout (coin) owner from
183 // computing future proof-of-stake generated by this txout at the time
184 // of transaction confirmation. To meet kernel protocol, the txout
185 // must hash with a future stake modifier to generate the proof.
186 // Stake modifier consists of bits each of which is contributed from a
187 // selected block of a given block group in the past.
188 // The selection of a block is based on a hash of the block's proof-hash and
189 // the previous stake modifier.
190 // Stake modifier is recomputed at a fixed time interval instead of every
191 // block. This is to make it difficult for an attacker to gain control of
192 // additional bits in the stake modifier, even after generating a chain of
194 bool ComputeNextStakeModifier(const CBlockIndex* pindexCurrent, uint64_t& nStakeModifier, bool& fGeneratedStakeModifier)
197 fGeneratedStakeModifier = false;
198 const CBlockIndex* pindexPrev = pindexCurrent->pprev;
201 fGeneratedStakeModifier = true;
202 return true; // genesis block's modifier is 0
205 // First find current stake modifier and its generation block time
206 // if it's not old enough, return the same stake modifier
207 int64_t nModifierTime = 0;
208 if (!GetLastStakeModifier(pindexPrev, nStakeModifier, nModifierTime))
209 return error("ComputeNextStakeModifier: unable to get last modifier");
212 printf("ComputeNextStakeModifier: prev modifier=0x%016" PRIx64 " time=%s epoch=%u\n", nStakeModifier, DateTimeStrFormat(nModifierTime).c_str(), (unsigned int)nModifierTime);
214 if (nModifierTime / nModifierInterval >= pindexPrev->GetBlockTime() / nModifierInterval)
218 printf("ComputeNextStakeModifier: no new interval keep current modifier: pindexPrev nHeight=%d nTime=%u\n", pindexPrev->nHeight, (unsigned int)pindexPrev->GetBlockTime());
222 if (nModifierTime / nModifierInterval >= pindexCurrent->GetBlockTime() / nModifierInterval)
224 // fixed interval protocol requires current block timestamp also be in a different modifier interval
225 if (IsFixedModifierInterval(pindexCurrent->nTime))
229 printf("ComputeNextStakeModifier: no new interval keep current modifier: pindexCurrent nHeight=%d nTime=%u\n", pindexCurrent->nHeight, (unsigned int)pindexCurrent->GetBlockTime());
237 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());
242 // Sort candidate blocks by timestamp
243 vector<pair<int64_t, uint256> > vSortedByTimestamp;
244 vSortedByTimestamp.reserve(64 * nModifierInterval / nStakeTargetSpacing);
245 int64_t nSelectionInterval = GetStakeModifierSelectionInterval();
246 int64_t nSelectionIntervalStart = (pindexPrev->GetBlockTime() / nModifierInterval) * nModifierInterval - nSelectionInterval;
247 const CBlockIndex* pindex = pindexPrev;
248 while (pindex && pindex->GetBlockTime() >= nSelectionIntervalStart)
250 vSortedByTimestamp.push_back(make_pair(pindex->GetBlockTime(), pindex->GetBlockHash()));
251 pindex = pindex->pprev;
253 int nHeightFirstCandidate = pindex ? (pindex->nHeight + 1) : 0;
254 reverse(vSortedByTimestamp.begin(), vSortedByTimestamp.end());
255 sort(vSortedByTimestamp.begin(), vSortedByTimestamp.end());
257 // Select 64 blocks from candidate blocks to generate stake modifier
258 uint64_t nStakeModifierNew = 0;
259 int64_t nSelectionIntervalStop = nSelectionIntervalStart;
260 map<uint256, const CBlockIndex*> mapSelectedBlocks;
261 for (int nRound=0; nRound<min(64, (int)vSortedByTimestamp.size()); nRound++)
263 // add an interval section to the current selection round
264 nSelectionIntervalStop += GetStakeModifierSelectionIntervalSection(nRound);
265 // select a block from the candidates of current round
266 if (!SelectBlockFromCandidates(vSortedByTimestamp, mapSelectedBlocks, nSelectionIntervalStop, nStakeModifier, &pindex))
267 return error("ComputeNextStakeModifier: unable to select block at round %d", nRound);
268 // write the entropy bit of the selected block
269 nStakeModifierNew |= (((uint64_t)pindex->GetStakeEntropyBit()) << nRound);
270 // add the selected block from candidates to selected list
271 mapSelectedBlocks.insert(make_pair(pindex->GetBlockHash(), pindex));
272 if (fDebug && GetBoolArg("-printstakemodifier"))
273 printf("ComputeNextStakeModifier: selected round %d stop=%s height=%d bit=%d\n", nRound, DateTimeStrFormat(nSelectionIntervalStop).c_str(), pindex->nHeight, pindex->GetStakeEntropyBit());
276 // Print selection map for visualization of the selected blocks
277 if (fDebug && GetBoolArg("-printstakemodifier"))
279 string strSelectionMap = "";
280 // '-' indicates proof-of-work blocks not selected
281 strSelectionMap.insert(0, pindexPrev->nHeight - nHeightFirstCandidate + 1, '-');
283 while (pindex && pindex->nHeight >= nHeightFirstCandidate)
285 // '=' indicates proof-of-stake blocks not selected
286 if (pindex->IsProofOfStake())
287 strSelectionMap.replace(pindex->nHeight - nHeightFirstCandidate, 1, "=");
288 pindex = pindex->pprev;
290 for (const auto& item : mapSelectedBlocks)
292 // 'S' indicates selected proof-of-stake blocks
293 // 'W' indicates selected proof-of-work blocks
294 strSelectionMap.replace(item.second->nHeight - nHeightFirstCandidate, 1, item.second->IsProofOfStake()? "S" : "W");
296 printf("ComputeNextStakeModifier: selection height [%d, %d] map %s\n", nHeightFirstCandidate, pindexPrev->nHeight, strSelectionMap.c_str());
300 printf("ComputeNextStakeModifier: new modifier=0x%016" PRIx64 " time=%s\n", nStakeModifierNew, DateTimeStrFormat(pindexPrev->GetBlockTime()).c_str());
303 nStakeModifier = nStakeModifierNew;
304 fGeneratedStakeModifier = true;
308 // The stake modifier used to hash for a stake kernel is chosen as the stake
309 // modifier about a selection interval later than the coin generating the kernel
310 static bool GetKernelStakeModifier(uint256 hashBlockFrom, uint64_t& nStakeModifier, int& nStakeModifierHeight, int64_t& nStakeModifierTime, bool fPrintProofOfStake)
313 if (!mapBlockIndex.count(hashBlockFrom))
314 return error("GetKernelStakeModifier() : block not indexed");
315 const CBlockIndex* pindexFrom = mapBlockIndex[hashBlockFrom];
316 nStakeModifierHeight = pindexFrom->nHeight;
317 nStakeModifierTime = pindexFrom->GetBlockTime();
318 int64_t nStakeModifierSelectionInterval = GetStakeModifierSelectionInterval();
319 const CBlockIndex* pindex = pindexFrom;
320 // loop to find the stake modifier later by a selection interval
321 while (nStakeModifierTime < pindexFrom->GetBlockTime() + nStakeModifierSelectionInterval)
324 { // reached best block; may happen if node is behind on block chain
325 if (fPrintProofOfStake || (pindex->GetBlockTime() + nStakeMinAge - nStakeModifierSelectionInterval > GetAdjustedTime()))
326 return error("GetKernelStakeModifier() : reached best block %s at height %d from block %s",
327 pindex->GetBlockHash().ToString().c_str(), pindex->nHeight, hashBlockFrom.ToString().c_str());
331 pindex = pindex->pnext;
332 if (pindex->GeneratedStakeModifier())
334 nStakeModifierHeight = pindex->nHeight;
335 nStakeModifierTime = pindex->GetBlockTime();
338 nStakeModifier = pindex->nStakeModifier;
342 bool GetKernelStakeModifier(uint256 hashBlockFrom, uint64_t& nStakeModifier)
344 int nStakeModifierHeight;
345 int64_t nStakeModifierTime;
347 return GetKernelStakeModifier(hashBlockFrom, nStakeModifier, nStakeModifierHeight, nStakeModifierTime, false);
351 // ppcoin kernel protocol
352 // coinstake must meet hash target according to the protocol:
353 // kernel (input 0) must meet the formula
354 // hash(nStakeModifier + txPrev.block.nTime + txPrev.offset + txPrev.nTime + txPrev.vout.n + nTime) < bnTarget * nCoinDayWeight
355 // this ensures that the chance of getting a coinstake is proportional to the
356 // amount of coin age one owns.
357 // The reason this hash is chosen is the following:
358 // nStakeModifier: scrambles computation to make it very difficult to precompute
359 // future proof-of-stake at the time of the coin's confirmation
360 // txPrev.block.nTime: prevent nodes from guessing a good timestamp to
361 // generate transaction for future advantage
362 // txPrev.offset: offset of txPrev inside block, to reduce the chance of
363 // nodes generating coinstake at the same time
364 // txPrev.nTime: reduce the chance of nodes generating coinstake at the same
366 // txPrev.vout.n: output number of txPrev, to reduce the chance of nodes
367 // generating coinstake at the same time
368 // block/tx hash should not be used here as they can be generated in vast
369 // quantities so as to generate blocks faster, degrading the system back into
370 // a proof-of-work situation.
372 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)
374 if (nTimeTx < txPrev.nTime) // Transaction timestamp violation
375 return error("CheckStakeKernelHash() : nTime violation");
377 uint32_t nTimeBlockFrom = blockFrom.GetBlockTime();
378 if (nTimeBlockFrom + nStakeMinAge > nTimeTx) // Min age requirement
379 return error("CheckStakeKernelHash() : min age violation");
381 CBigNum bnTargetPerCoinDay;
382 bnTargetPerCoinDay.SetCompact(nBits);
383 int64_t nValueIn = txPrev.vout[prevout.n].nValue;
385 uint256 hashBlockFrom = blockFrom.GetHash();
387 CBigNum bnCoinDayWeight = CBigNum(nValueIn) * GetWeight((int64_t)txPrev.nTime, (int64_t)nTimeTx) / COIN / nOneDay;
388 targetProofOfStake = (bnCoinDayWeight * bnTargetPerCoinDay).getuint256();
391 CDataStream ss(SER_GETHASH, 0);
392 uint64_t nStakeModifier = 0;
393 int nStakeModifierHeight = 0;
394 int64_t nStakeModifierTime = 0;
396 if (!GetKernelStakeModifier(hashBlockFrom, nStakeModifier, nStakeModifierHeight, nStakeModifierTime, fPrintProofOfStake))
398 ss << nStakeModifier;
400 ss << nTimeBlockFrom << nTxPrevOffset << txPrev.nTime << prevout.n << nTimeTx;
401 hashProofOfStake = Hash(ss.begin(), ss.end());
402 if (fPrintProofOfStake)
404 printf("CheckStakeKernelHash() : using modifier 0x%016" PRIx64 " at height=%d timestamp=%s for block from height=%d timestamp=%s\n",
405 nStakeModifier, nStakeModifierHeight,
406 DateTimeStrFormat(nStakeModifierTime).c_str(),
407 mapBlockIndex[hashBlockFrom]->nHeight,
408 DateTimeStrFormat(blockFrom.GetBlockTime()).c_str());
409 printf("CheckStakeKernelHash() : check modifier=0x%016" PRIx64 " nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashTarget=%s hashProof=%s\n",
411 nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx,
412 targetProofOfStake.ToString().c_str(), hashProofOfStake.ToString().c_str());
415 // Now check if proof-of-stake hash meets target protocol
416 if (CBigNum(hashProofOfStake) > bnCoinDayWeight * bnTargetPerCoinDay)
418 if (fDebug && !fPrintProofOfStake)
420 printf("CheckStakeKernelHash() : using modifier 0x%016" PRIx64 " at height=%d timestamp=%s for block from height=%d timestamp=%s\n",
421 nStakeModifier, nStakeModifierHeight,
422 DateTimeStrFormat(nStakeModifierTime).c_str(),
423 mapBlockIndex[hashBlockFrom]->nHeight,
424 DateTimeStrFormat(blockFrom.GetBlockTime()).c_str());
425 printf("CheckStakeKernelHash() : pass modifier=0x%016" PRIx64 " nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashTarget=%s hashProof=%s\n",
427 nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx,
428 targetProofOfStake.ToString().c_str(), hashProofOfStake.ToString().c_str());
433 // Scan given kernel for solution
434 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)
436 // TODO: custom threads amount
438 uint32_t nThreads = boost::thread::hardware_concurrency();
442 printf("Warning: hardware_concurrency() failed in %s:%d\n", __FILE__, __LINE__);
444 uint32_t nPart = (SearchInterval.second - SearchInterval.first) / nThreads;
446 KernelWorker *workers = new KernelWorker[nThreads];
448 boost::thread_group group;
449 for(size_t i = 0; i < nThreads; i++)
451 uint32_t nBegin = SearchInterval.first + nPart * i;
452 uint32_t nEnd = SearchInterval.first + nPart * (i + 1);
453 workers[i] = KernelWorker(kernel, nBits, nInputTxTime, nValueIn, nBegin, nEnd);
454 boost::function<void()> workerFnc = boost::bind(&KernelWorker::Do, &workers[i]);
455 group.create_thread(workerFnc);
461 for(size_t i = 0; i < nThreads; i++)
463 std::vector<std::pair<uint256, uint32_t> > ws = workers[i].GetSolutions();
464 solutions.insert(solutions.end(), ws.begin(), ws.end());
469 if (solutions.size() == 0)
478 // Check kernel hash target and coinstake signature
479 bool CheckProofOfStake(const CTransaction& tx, unsigned int nBits, uint256& hashProofOfStake, uint256& targetProofOfStake)
481 if (!tx.IsCoinStake())
482 return error("CheckProofOfStake() : called on non-coinstake %s", tx.GetHash().ToString().c_str());
484 // Kernel (input 0) must match the stake hash target per coin age (nBits)
485 const CTxIn& txin = tx.vin[0];
487 // First try finding the previous transaction in database
491 if (!txPrev.ReadFromDisk(txdb, txin.prevout, txindex))
492 return tx.DoS(1, error("CheckProofOfStake() : INFO: read txPrev failed")); // previous transaction not in main chain, may occur during initial download
495 if (!VerifySignature(txPrev, tx, 0, MANDATORY_SCRIPT_VERIFY_FLAGS, 0))
496 return tx.DoS(100, error("CheckProofOfStake() : VerifySignature failed on coinstake %s", tx.GetHash().ToString().c_str()));
500 if (!block.ReadFromDisk(txindex.pos.nFile, txindex.pos.nBlockPos, false))
501 return fDebug? error("CheckProofOfStake() : read block failed") : false; // unable to read block of previous transaction
503 if (!CheckStakeKernelHash(nBits, block, txindex.pos.nTxPos - txindex.pos.nBlockPos, txPrev, txin.prevout, tx.nTime, hashProofOfStake, targetProofOfStake, fDebug))
504 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
509 // Get stake modifier checksum
510 uint32_t GetStakeModifierChecksum(const CBlockIndex* pindex)
512 assert (pindex->pprev || pindex->GetBlockHash() == (!fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet));
513 // Hash previous checksum with flags, hashProofOfStake and nStakeModifier
514 CDataStream ss(SER_GETHASH, 0);
516 ss << pindex->pprev->nStakeModifierChecksum;
517 ss << pindex->nFlags << pindex->hashProofOfStake << pindex->nStakeModifier;
518 uint256 hashChecksum = Hash(ss.begin(), ss.end());
519 hashChecksum >>= (256 - 32);
520 return static_cast<uint32_t>(hashChecksum.Get64());
523 // Check stake modifier hard checkpoints
524 bool CheckStakeModifierCheckpoints(int nHeight, uint32_t nStakeModifierChecksum)
526 MapModifierCheckpoints& checkpoints = (fTestNet ? mapStakeModifierCheckpointsTestNet : mapStakeModifierCheckpoints);
528 if (checkpoints.count(nHeight))
529 return nStakeModifierChecksum == checkpoints[nHeight];