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"
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 )
44 // Hard checkpoints of stake modifiers to ensure they are deterministic (testNet)
45 static std::map<int, unsigned int> mapStakeModifierCheckpointsTestNet =
46 boost::assign::map_list_of
50 // Pregenerated entropy bits table (from genesis to #9689)
52 // Bits are packed into array of 256 bit integers:
54 // * array index calculated as nHeight / 256
55 // * position of bit is calculated as nHeight & 0xFF.
57 const uint256 entropyStore[] = {
58 uint256("0x4555b4dcc1d690ddd9b810c90c66e82b18bf4f43cc887246c418383ec120a5ab"),
59 uint256("0xaa6d1198412fa77608addf6549c9198a22155e8afd7a9ded6179f6b7cfc66b0c"),
60 uint256("0x9442fabfa4116fb14a9769c2eea003845a1f5c3a0260f36b497d68f3a3cd4078"),
61 uint256("0x0e769042a9a98e42388195d699574b822d06515f7053ad884c53d7ee059f05b1"),
62 uint256("0x7005aac20baf70251aebfe3f1b95987d83ef1e3e6963de8fed601d4dd07bf7cf"),
63 uint256("0x58952c5c3de188f2e33c38d3f53d7bf44f9bc545a4289d266696273fa821be66"),
64 uint256("0x50b6c2ed780c08aaec3f7665b1b6004206243e3866456fc910b83b52d07eeb63"),
65 uint256("0x563841eefca85ba3384986c58100408ae3f1ba2ac727e1ac910ce154a06c702f"),
66 uint256("0x79275b03938b3e27a9b01a7f7953c6c487c58355f5d4169accfbb800213ffd13"),
67 uint256("0xd783f2538b3ed18f135af90adc687c5646d93aeaeaabc6667be94f7aa0a2d366"),
68 uint256("0xb441d0c175c40c8e88b09d88ea008af79cbed2d28219427d2e72fda682974db8"),
69 uint256("0x3204c43bd41f2e19628af3b0c9aca3db15bca4c8705d51056e7b17a319c04715"),
70 uint256("0x7e80e6ab7857d8f2f261a0a49c783bd800b365b8c9b85cc0e13f73904b0dcaa9"),
71 uint256("0xefaaee60ed82d2ad145c0e347941fdb131eb8fd289a45eef07121a93f283c5f1"),
72 uint256("0x3efc86e4334da332c1fd4c12513c40cff689f3efdc7f9913230822adacdda4f9"),
73 uint256("0xf0d6b8f38599a017fa35d1fbbf9ef51eca5ebc5b286aadba40c4c3e1d9bace0c"),
74 uint256("0x286a67f27323486036a0a92d35382fc8963c0c00bad331723318b4b9fdb2b56e"),
75 uint256("0xecbfaaa6567c54f08c4d5bd0118a2d7b58740f42cbfc73aa1536c1f5f76de87c"),
76 uint256("0xf9a4de1c5c46520de5aaf10d3796cf0e27ddce98b3398357f5726a949664e308"),
77 uint256("0xd75e6c4dc4be08401e3478d2467d9ab96a62af4f255c04a82c41af0de0a487bb"),
78 uint256("0x1a82c3bc6ad6047294c16571b5e2b7316c97bf8813e7da15798b9820d67e39f2"),
79 uint256("0xb49be0080de564e01829ded7e7971979565a741c5975dc9978dcc020192d396c"),
80 uint256("0x0d8eed113be67663b5a15a0625a9b49792b5ea59c005c4f405914877acab7000"),
81 uint256("0x8f9d46e2bc05a218ffa942965b747056197d393b097085523640cd59e07fe7c7"),
82 uint256("0x7a63ab40bc7f40ac2ebe9ede438d97b45fa6ed6f8419016da8d5f7a670111dda"),
83 uint256("0x63fbcc080448c43d6cf915c958314feff7a95a52ba43a68c05fc281d3a522d25"),
84 uint256("0xf834cf824c326d3ea861ea1e85dc3289265e37045981e28208e7344a7f8081d7"),
85 uint256("0xb4edc22ec98cc49b2f5af5bae3f52f5e6058280f74f2c432c2dd89ae49acceb8"),
86 uint256("0x0fe596037dcf81bf5c64f39755261c404ed088af5c8c31dd7549b6657ee92365"),
87 uint256("0xbbad51a0aeba254b01d18c328de9e932b9b859b61e622c325d64e2211b5e413d"),
88 uint256("0xabf0194cc787be938bc51c7fdf1cae4ec79e65ebab8fa8b8f40541c44ef384b0"),
89 uint256("0x83bc12d6fdbd3e854cb91c4ca7dfba3c38e8714121af88c8a8abdb33e5002438"),
90 uint256("0x71a2513026cabaedcbe55aeb6dc8049e5b763a3f54f10c33dd333624f764b38c"),
91 uint256("0xee6725632ff5c025dff6a18cd059875dcae20f399b03bccba13d9d5fcf6d9d9a"),
92 uint256("0xa168a2741d1e7e50cc74b79f695c25ffd3576e6bd61353c2a20e569fd63b2dac"),
93 uint256("0x6e462d2a87bfde9398b6747f94a8ed6a01e4d96c5b4372df5c910c106c48bd13"),
94 uint256("0x8eeb696181957c4b22434028990f49cb30006827c73860e77e2eecf5c38be99d"),
95 uint256("0x3188aaa65877b166f05cdc48f55b1f77a7d6fb221c395596d990ae5647e9ba96")
98 // Whether the given block is subject to new modifier protocol
99 bool IsFixedModifierInterval(unsigned int nTimeBlock)
101 return (nTimeBlock >= (fTestNet? nModifierTestSwitchTime : nModifierSwitchTime));
104 // Get the last stake modifier and its generation time from a given block
105 static bool GetLastStakeModifier(const CBlockIndex* pindex, uint64_t& nStakeModifier, int64_t& nModifierTime)
108 return error("GetLastStakeModifier: null pindex");
109 while (pindex && pindex->pprev && !pindex->GeneratedStakeModifier())
110 pindex = pindex->pprev;
111 if (!pindex->GeneratedStakeModifier())
112 return error("GetLastStakeModifier: no generation at genesis block");
113 nStakeModifier = pindex->nStakeModifier;
114 nModifierTime = pindex->GetBlockTime();
118 // Get selection interval section (in seconds)
119 static int64_t GetStakeModifierSelectionIntervalSection(int nSection)
121 assert (nSection >= 0 && nSection < 64);
122 return (nModifierInterval * 63 / (63 + ((63 - nSection) * (MODIFIER_INTERVAL_RATIO - 1))));
125 // Get stake modifier selection interval (in seconds)
126 static int64_t GetStakeModifierSelectionInterval()
128 int64_t nSelectionInterval = 0;
129 for (int nSection=0; nSection<64; nSection++)
130 nSelectionInterval += GetStakeModifierSelectionIntervalSection(nSection);
131 return nSelectionInterval;
134 // select a block from the candidate blocks in vSortedByTimestamp, excluding
135 // already selected blocks in vSelectedBlocks, and with timestamp up to
136 // nSelectionIntervalStop.
137 static bool SelectBlockFromCandidates(vector<pair<int64_t, uint256> >& vSortedByTimestamp, map<uint256, const CBlockIndex*>& mapSelectedBlocks,
138 int64_t nSelectionIntervalStop, uint64_t nStakeModifierPrev, const CBlockIndex** pindexSelected)
140 bool fSelected = false;
141 uint256 hashBest = 0;
142 *pindexSelected = (const CBlockIndex*) 0;
143 BOOST_FOREACH(const PAIRTYPE(int64_t, uint256)& item, vSortedByTimestamp)
145 if (!mapBlockIndex.count(item.second))
146 return error("SelectBlockFromCandidates: failed to find block index for candidate block %s", item.second.ToString().c_str());
147 const CBlockIndex* pindex = mapBlockIndex[item.second];
148 if (fSelected && pindex->GetBlockTime() > nSelectionIntervalStop)
150 if (mapSelectedBlocks.count(pindex->GetBlockHash()) > 0)
152 // compute the selection hash by hashing its proof-hash and the
153 // previous proof-of-stake modifier
154 uint256 hashProof = pindex->IsProofOfStake()? pindex->hashProofOfStake : pindex->GetBlockHash();
155 CDataStream ss(SER_GETHASH, 0);
156 ss << hashProof << nStakeModifierPrev;
157 uint256 hashSelection = Hash(ss.begin(), ss.end());
158 // the selection hash is divided by 2**32 so that proof-of-stake block
159 // is always favored over proof-of-work block. this is to preserve
160 // the energy efficiency property
161 if (pindex->IsProofOfStake())
162 hashSelection >>= 32;
163 if (fSelected && hashSelection < hashBest)
165 hashBest = hashSelection;
166 *pindexSelected = pindex;
171 hashBest = hashSelection;
172 *pindexSelected = pindex;
175 if (fDebug && GetBoolArg("-printstakemodifier"))
176 printf("SelectBlockFromCandidates: selection hash=%s\n", hashBest.ToString().c_str());
180 // Stake Modifier (hash modifier of proof-of-stake):
181 // The purpose of stake modifier is to prevent a txout (coin) owner from
182 // computing future proof-of-stake generated by this txout at the time
183 // of transaction confirmation. To meet kernel protocol, the txout
184 // must hash with a future stake modifier to generate the proof.
185 // Stake modifier consists of bits each of which is contributed from a
186 // selected block of a given block group in the past.
187 // The selection of a block is based on a hash of the block's proof-hash and
188 // the previous stake modifier.
189 // Stake modifier is recomputed at a fixed time interval instead of every
190 // block. This is to make it difficult for an attacker to gain control of
191 // additional bits in the stake modifier, even after generating a chain of
193 bool ComputeNextStakeModifier(const CBlockIndex* pindexCurrent, uint64_t& nStakeModifier, bool& fGeneratedStakeModifier)
196 fGeneratedStakeModifier = false;
197 const CBlockIndex* pindexPrev = pindexCurrent->pprev;
200 fGeneratedStakeModifier = true;
201 return true; // genesis block's modifier is 0
204 // First find current stake modifier and its generation block time
205 // if it's not old enough, return the same stake modifier
206 int64_t nModifierTime = 0;
207 if (!GetLastStakeModifier(pindexPrev, nStakeModifier, nModifierTime))
208 return error("ComputeNextStakeModifier: unable to get last modifier");
211 printf("ComputeNextStakeModifier: prev modifier=0x%016" PRIx64 " time=%s epoch=%u\n", nStakeModifier, DateTimeStrFormat(nModifierTime).c_str(), (unsigned int)nModifierTime);
213 if (nModifierTime / nModifierInterval >= pindexPrev->GetBlockTime() / nModifierInterval)
217 printf("ComputeNextStakeModifier: no new interval keep current modifier: pindexPrev nHeight=%d nTime=%u\n", pindexPrev->nHeight, (unsigned int)pindexPrev->GetBlockTime());
221 if (nModifierTime / nModifierInterval >= pindexCurrent->GetBlockTime() / nModifierInterval)
223 // fixed interval protocol requires current block timestamp also be in a different modifier interval
224 if (IsFixedModifierInterval(pindexCurrent->nTime))
228 printf("ComputeNextStakeModifier: no new interval keep current modifier: pindexCurrent nHeight=%d nTime=%u\n", pindexCurrent->nHeight, (unsigned int)pindexCurrent->GetBlockTime());
236 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());
241 // Sort candidate blocks by timestamp
242 vector<pair<int64_t, uint256> > vSortedByTimestamp;
243 vSortedByTimestamp.reserve(64 * nModifierInterval / nStakeTargetSpacing);
244 int64_t nSelectionInterval = GetStakeModifierSelectionInterval();
245 int64_t nSelectionIntervalStart = (pindexPrev->GetBlockTime() / nModifierInterval) * nModifierInterval - nSelectionInterval;
246 const CBlockIndex* pindex = pindexPrev;
247 while (pindex && pindex->GetBlockTime() >= nSelectionIntervalStart)
249 vSortedByTimestamp.push_back(make_pair(pindex->GetBlockTime(), pindex->GetBlockHash()));
250 pindex = pindex->pprev;
252 int nHeightFirstCandidate = pindex ? (pindex->nHeight + 1) : 0;
253 reverse(vSortedByTimestamp.begin(), vSortedByTimestamp.end());
254 sort(vSortedByTimestamp.begin(), vSortedByTimestamp.end());
256 // Select 64 blocks from candidate blocks to generate stake modifier
257 uint64_t nStakeModifierNew = 0;
258 int64_t nSelectionIntervalStop = nSelectionIntervalStart;
259 map<uint256, const CBlockIndex*> mapSelectedBlocks;
260 for (int nRound=0; nRound<min(64, (int)vSortedByTimestamp.size()); nRound++)
262 // add an interval section to the current selection round
263 nSelectionIntervalStop += GetStakeModifierSelectionIntervalSection(nRound);
264 // select a block from the candidates of current round
265 if (!SelectBlockFromCandidates(vSortedByTimestamp, mapSelectedBlocks, nSelectionIntervalStop, nStakeModifier, &pindex))
266 return error("ComputeNextStakeModifier: unable to select block at round %d", nRound);
267 // write the entropy bit of the selected block
268 nStakeModifierNew |= (((uint64_t)pindex->GetStakeEntropyBit()) << nRound);
269 // add the selected block from candidates to selected list
270 mapSelectedBlocks.insert(make_pair(pindex->GetBlockHash(), pindex));
271 if (fDebug && GetBoolArg("-printstakemodifier"))
272 printf("ComputeNextStakeModifier: selected round %d stop=%s height=%d bit=%d\n", nRound, DateTimeStrFormat(nSelectionIntervalStop).c_str(), pindex->nHeight, pindex->GetStakeEntropyBit());
275 // Print selection map for visualization of the selected blocks
276 if (fDebug && GetBoolArg("-printstakemodifier"))
278 string strSelectionMap = "";
279 // '-' indicates proof-of-work blocks not selected
280 strSelectionMap.insert(0, pindexPrev->nHeight - nHeightFirstCandidate + 1, '-');
282 while (pindex && pindex->nHeight >= nHeightFirstCandidate)
284 // '=' indicates proof-of-stake blocks not selected
285 if (pindex->IsProofOfStake())
286 strSelectionMap.replace(pindex->nHeight - nHeightFirstCandidate, 1, "=");
287 pindex = pindex->pprev;
289 BOOST_FOREACH(const PAIRTYPE(uint256, const CBlockIndex*)& item, mapSelectedBlocks)
291 // 'S' indicates selected proof-of-stake blocks
292 // 'W' indicates selected proof-of-work blocks
293 strSelectionMap.replace(item.second->nHeight - nHeightFirstCandidate, 1, item.second->IsProofOfStake()? "S" : "W");
295 printf("ComputeNextStakeModifier: selection height [%d, %d] map %s\n", nHeightFirstCandidate, pindexPrev->nHeight, strSelectionMap.c_str());
299 printf("ComputeNextStakeModifier: new modifier=0x%016" PRIx64 " time=%s\n", nStakeModifierNew, DateTimeStrFormat(pindexPrev->GetBlockTime()).c_str());
302 nStakeModifier = nStakeModifierNew;
303 fGeneratedStakeModifier = true;
307 // The stake modifier used to hash for a stake kernel is chosen as the stake
308 // modifier about a selection interval later than the coin generating the kernel
309 static bool GetKernelStakeModifier(uint256 hashBlockFrom, uint64_t& nStakeModifier, int& nStakeModifierHeight, int64_t& nStakeModifierTime, bool fPrintProofOfStake)
312 if (!mapBlockIndex.count(hashBlockFrom))
313 return error("GetKernelStakeModifier() : block not indexed");
314 const CBlockIndex* pindexFrom = mapBlockIndex[hashBlockFrom];
315 nStakeModifierHeight = pindexFrom->nHeight;
316 nStakeModifierTime = pindexFrom->GetBlockTime();
317 int64_t nStakeModifierSelectionInterval = GetStakeModifierSelectionInterval();
318 const CBlockIndex* pindex = pindexFrom;
319 // loop to find the stake modifier later by a selection interval
320 while (nStakeModifierTime < pindexFrom->GetBlockTime() + nStakeModifierSelectionInterval)
323 { // reached best block; may happen if node is behind on block chain
324 if (fPrintProofOfStake || (pindex->GetBlockTime() + nStakeMinAge - nStakeModifierSelectionInterval > GetAdjustedTime()))
325 return error("GetKernelStakeModifier() : reached best block %s at height %d from block %s",
326 pindex->GetBlockHash().ToString().c_str(), pindex->nHeight, hashBlockFrom.ToString().c_str());
330 pindex = pindex->pnext;
331 if (pindex->GeneratedStakeModifier())
333 nStakeModifierHeight = pindex->nHeight;
334 nStakeModifierTime = pindex->GetBlockTime();
337 nStakeModifier = pindex->nStakeModifier;
341 bool GetKernelStakeModifier(uint256 hashBlockFrom, uint64_t& nStakeModifier)
343 int nStakeModifierHeight;
344 int64_t nStakeModifierTime;
346 return GetKernelStakeModifier(hashBlockFrom, nStakeModifier, nStakeModifierHeight, nStakeModifierTime, false);
350 // ppcoin kernel protocol
351 // coinstake must meet hash target according to the protocol:
352 // kernel (input 0) must meet the formula
353 // hash(nStakeModifier + txPrev.block.nTime + txPrev.offset + txPrev.nTime + txPrev.vout.n + nTime) < bnTarget * nCoinDayWeight
354 // this ensures that the chance of getting a coinstake is proportional to the
355 // amount of coin age one owns.
356 // The reason this hash is chosen is the following:
357 // nStakeModifier: scrambles computation to make it very difficult to precompute
358 // future proof-of-stake at the time of the coin's confirmation
359 // txPrev.block.nTime: prevent nodes from guessing a good timestamp to
360 // generate transaction for future advantage
361 // txPrev.offset: offset of txPrev inside block, to reduce the chance of
362 // nodes generating coinstake at the same time
363 // txPrev.nTime: reduce the chance of nodes generating coinstake at the same
365 // txPrev.vout.n: output number of txPrev, to reduce the chance of nodes
366 // generating coinstake at the same time
367 // block/tx hash should not be used here as they can be generated in vast
368 // quantities so as to generate blocks faster, degrading the system back into
369 // a proof-of-work situation.
371 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)
373 if (nTimeTx < txPrev.nTime) // Transaction timestamp violation
374 return error("CheckStakeKernelHash() : nTime violation");
376 uint32_t nTimeBlockFrom = blockFrom.GetBlockTime();
377 if (nTimeBlockFrom + nStakeMinAge > nTimeTx) // Min age requirement
378 return error("CheckStakeKernelHash() : min age violation");
380 CBigNum bnTargetPerCoinDay;
381 bnTargetPerCoinDay.SetCompact(nBits);
382 int64_t nValueIn = txPrev.vout[prevout.n].nValue;
384 uint256 hashBlockFrom = blockFrom.GetHash();
386 CBigNum bnCoinDayWeight = CBigNum(nValueIn) * GetWeight((int64_t)txPrev.nTime, (int64_t)nTimeTx) / COIN / nOneDay;
387 targetProofOfStake = (bnCoinDayWeight * bnTargetPerCoinDay).getuint256();
390 CDataStream ss(SER_GETHASH, 0);
391 uint64_t nStakeModifier = 0;
392 int nStakeModifierHeight = 0;
393 int64_t nStakeModifierTime = 0;
395 if (!GetKernelStakeModifier(hashBlockFrom, nStakeModifier, nStakeModifierHeight, nStakeModifierTime, fPrintProofOfStake))
397 ss << nStakeModifier;
399 ss << nTimeBlockFrom << nTxPrevOffset << txPrev.nTime << prevout.n << nTimeTx;
400 hashProofOfStake = Hash(ss.begin(), ss.end());
401 if (fPrintProofOfStake)
403 printf("CheckStakeKernelHash() : using modifier 0x%016" PRIx64 " at height=%d timestamp=%s for block from height=%d timestamp=%s\n",
404 nStakeModifier, nStakeModifierHeight,
405 DateTimeStrFormat(nStakeModifierTime).c_str(),
406 mapBlockIndex[hashBlockFrom]->nHeight,
407 DateTimeStrFormat(blockFrom.GetBlockTime()).c_str());
408 printf("CheckStakeKernelHash() : check modifier=0x%016" PRIx64 " nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashTarget=%s hashProof=%s\n",
410 nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx,
411 targetProofOfStake.ToString().c_str(), hashProofOfStake.ToString().c_str());
414 // Now check if proof-of-stake hash meets target protocol
415 if (CBigNum(hashProofOfStake) > bnCoinDayWeight * bnTargetPerCoinDay)
417 if (fDebug && !fPrintProofOfStake)
419 printf("CheckStakeKernelHash() : using modifier 0x%016" PRIx64 " at height=%d timestamp=%s for block from height=%d timestamp=%s\n",
420 nStakeModifier, nStakeModifierHeight,
421 DateTimeStrFormat(nStakeModifierTime).c_str(),
422 mapBlockIndex[hashBlockFrom]->nHeight,
423 DateTimeStrFormat(blockFrom.GetBlockTime()).c_str());
424 printf("CheckStakeKernelHash() : pass modifier=0x%016" PRIx64 " nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashTarget=%s hashProof=%s\n",
426 nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx,
427 targetProofOfStake.ToString().c_str(), hashProofOfStake.ToString().c_str());
432 // Scan given kernel for solution
433 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)
435 // TODO: custom threads amount
437 uint32_t nThreads = boost::thread::hardware_concurrency();
438 uint32_t nPart = (SearchInterval.second - SearchInterval.first) / nThreads;
441 KernelWorker *workers = new KernelWorker[nThreads];
443 boost::thread_group group;
444 for(size_t i = 0; i < nThreads; i++)
446 uint32_t nBegin = SearchInterval.first + nPart * i;
447 uint32_t nEnd = SearchInterval.first + nPart * (i + 1);
448 workers[i] = KernelWorker(kernel, nBits, nInputTxTime, nValueIn, nBegin, nEnd);
449 boost::function<void()> workerFnc = boost::bind(&KernelWorker::Do, &workers[i]);
450 group.create_thread(workerFnc);
456 for(size_t i = 0; i < nThreads; i++)
458 std::vector<std::pair<uint256, uint32_t> > ws = workers[i].GetSolutions();
459 solutions.insert(solutions.end(), ws.begin(), ws.end());
464 if (solutions.size() == 0)
473 // Check kernel hash target and coinstake signature
474 bool CheckProofOfStake(const CTransaction& tx, unsigned int nBits, uint256& hashProofOfStake, uint256& targetProofOfStake)
476 if (!tx.IsCoinStake())
477 return error("CheckProofOfStake() : called on non-coinstake %s", tx.GetHash().ToString().c_str());
479 // Kernel (input 0) must match the stake hash target per coin age (nBits)
480 const CTxIn& txin = tx.vin[0];
482 // First try finding the previous transaction in database
486 if (!txPrev.ReadFromDisk(txdb, txin.prevout, txindex))
487 return tx.DoS(1, error("CheckProofOfStake() : INFO: read txPrev failed")); // previous transaction not in main chain, may occur during initial download
494 if (!VerifySignature(txPrev, tx, 0, MANDATORY_SCRIPT_VERIFY_FLAGS, 0))
495 return tx.DoS(100, error("CheckProofOfStake() : VerifySignature failed on coinstake %s", tx.GetHash().ToString().c_str()));
499 if (!block.ReadFromDisk(txindex.pos.nFile, txindex.pos.nBlockPos, false))
500 return fDebug? error("CheckProofOfStake() : read block failed") : false; // unable to read block of previous transaction
502 if (!CheckStakeKernelHash(nBits, block, txindex.pos.nTxPos - txindex.pos.nBlockPos, txPrev, txin.prevout, tx.nTime, hashProofOfStake, targetProofOfStake, fDebug))
503 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
508 // Get stake modifier checksum
509 uint32_t GetStakeModifierChecksum(const CBlockIndex* pindex)
511 assert (pindex->pprev || pindex->GetBlockHash() == (!fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet));
512 // Hash previous checksum with flags, hashProofOfStake and nStakeModifier
513 CDataStream ss(SER_GETHASH, 0);
515 ss << pindex->pprev->nStakeModifierChecksum;
516 ss << pindex->nFlags << pindex->hashProofOfStake << pindex->nStakeModifier;
517 uint256 hashChecksum = Hash(ss.begin(), ss.end());
518 hashChecksum >>= (256 - 32);
519 return static_cast<uint32_t>(hashChecksum.Get64());
522 // Check stake modifier hard checkpoints
523 bool CheckStakeModifierCheckpoints(int nHeight, uint32_t nStakeModifierChecksum)
525 MapModifierCheckpoints& checkpoints = (fTestNet ? mapStakeModifierCheckpointsTestNet : mapStakeModifierCheckpoints);
527 if (checkpoints.count(nHeight))
528 return nStakeModifierChecksum == checkpoints[nHeight];