1 // Copyright (c) 2012-2013 The PPCoin developers
2 // Distributed under the MIT/X11 software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
5 #include <boost/assign/list_of.hpp>
10 extern unsigned int nStakeMaxAge;
11 extern unsigned int nStakeTargetSpacing;
16 // Protocol switch time for fixed kernel modifier interval
17 unsigned int nModifierSwitchTime = 1413763200; // Mon, 20 Oct 2014 00:00:00 GMT
18 unsigned int nModifierTestSwitchTime = 1397520000; // Tue, 15 Apr 2014 00:00:00 GMT
20 // Note: user must upgrade before the protocol switch deadline, otherwise it's required to
21 // re-download the blockchain. The timestamp of upgrade is recorded in the blockchain
23 unsigned int nModifierUpgradeTime = 0;
25 typedef std::map<int, unsigned int> MapModifierCheckpoints;
27 // Hard checkpoints of stake modifiers to ensure they are deterministic
28 static std::map<int, unsigned int> mapStakeModifierCheckpoints =
29 boost::assign::map_list_of
32 ( 12661, 0x5d84115du )
33 ( 37092, 0xd230afccu )
34 ( 44200, 0x05370164u )
35 ( 65000, 0xc8e7be6au )
36 ( 68600, 0x73a8cc4cu )
37 ( 92161, 0xe21a911au )
38 ( 98661, 0xd20c44d4u )
39 (143990, 0x9c592c78u )
42 // Hard checkpoints of stake modifiers to ensure they are deterministic (testNet)
43 static std::map<int, unsigned int> mapStakeModifierCheckpointsTestNet =
44 boost::assign::map_list_of
48 // Whether the given block is subject to new modifier protocol
49 bool IsFixedModifierInterval(unsigned int nTimeBlock)
51 return (nTimeBlock >= (fTestNet? nModifierTestSwitchTime : nModifierSwitchTime));
55 int64_t GetWeight(int64_t nIntervalBeginning, int64_t nIntervalEnd)
57 // Kernel hash weight starts from 0 at the 30-day min age
58 // this change increases active coins participating the hash and helps
59 // to secure the network when proof-of-stake difficulty is low
61 // Maximum TimeWeight is 90 days.
63 return min(nIntervalEnd - nIntervalBeginning - nStakeMinAge, (int64_t)nStakeMaxAge);
66 // Get the last stake modifier and its generation time from a given block
67 static bool GetLastStakeModifier(const CBlockIndex* pindex, uint64_t& nStakeModifier, int64_t& nModifierTime)
70 return error("GetLastStakeModifier: null pindex");
71 while (pindex && pindex->pprev && !pindex->GeneratedStakeModifier())
72 pindex = pindex->pprev;
73 if (!pindex->GeneratedStakeModifier())
74 return error("GetLastStakeModifier: no generation at genesis block");
75 nStakeModifier = pindex->nStakeModifier;
76 nModifierTime = pindex->GetBlockTime();
80 // Get selection interval section (in seconds)
81 static int64_t GetStakeModifierSelectionIntervalSection(int nSection)
83 assert (nSection >= 0 && nSection < 64);
84 return (nModifierInterval * 63 / (63 + ((63 - nSection) * (MODIFIER_INTERVAL_RATIO - 1))));
87 // Get stake modifier selection interval (in seconds)
88 static int64_t GetStakeModifierSelectionInterval()
90 int64_t nSelectionInterval = 0;
91 for (int nSection=0; nSection<64; nSection++)
92 nSelectionInterval += GetStakeModifierSelectionIntervalSection(nSection);
93 return nSelectionInterval;
96 // select a block from the candidate blocks in vSortedByTimestamp, excluding
97 // already selected blocks in vSelectedBlocks, and with timestamp up to
98 // nSelectionIntervalStop.
99 static bool SelectBlockFromCandidates(vector<pair<int64_t, uint256> >& vSortedByTimestamp, map<uint256, const CBlockIndex*>& mapSelectedBlocks,
100 int64_t nSelectionIntervalStop, uint64_t nStakeModifierPrev, const CBlockIndex** pindexSelected)
102 bool fSelected = false;
103 uint256 hashBest = 0;
104 *pindexSelected = (const CBlockIndex*) 0;
105 BOOST_FOREACH(const PAIRTYPE(int64_t, uint256)& item, vSortedByTimestamp)
107 if (!mapBlockIndex.count(item.second))
108 return error("SelectBlockFromCandidates: failed to find block index for candidate block %s", item.second.ToString().c_str());
109 const CBlockIndex* pindex = mapBlockIndex[item.second];
110 if (fSelected && pindex->GetBlockTime() > nSelectionIntervalStop)
112 if (mapSelectedBlocks.count(pindex->GetBlockHash()) > 0)
114 // compute the selection hash by hashing its proof-hash and the
115 // previous proof-of-stake modifier
116 uint256 hashProof = pindex->IsProofOfStake()? pindex->hashProofOfStake : pindex->GetBlockHash();
117 CDataStream ss(SER_GETHASH, 0);
118 ss << hashProof << nStakeModifierPrev;
119 uint256 hashSelection = Hash(ss.begin(), ss.end());
120 // the selection hash is divided by 2**32 so that proof-of-stake block
121 // is always favored over proof-of-work block. this is to preserve
122 // the energy efficiency property
123 if (pindex->IsProofOfStake())
124 hashSelection >>= 32;
125 if (fSelected && hashSelection < hashBest)
127 hashBest = hashSelection;
128 *pindexSelected = (const CBlockIndex*) pindex;
133 hashBest = hashSelection;
134 *pindexSelected = (const CBlockIndex*) pindex;
137 if (fDebug && GetBoolArg("-printstakemodifier"))
138 printf("SelectBlockFromCandidates: selection hash=%s\n", hashBest.ToString().c_str());
142 // Stake Modifier (hash modifier of proof-of-stake):
143 // The purpose of stake modifier is to prevent a txout (coin) owner from
144 // computing future proof-of-stake generated by this txout at the time
145 // of transaction confirmation. To meet kernel protocol, the txout
146 // must hash with a future stake modifier to generate the proof.
147 // Stake modifier consists of bits each of which is contributed from a
148 // selected block of a given block group in the past.
149 // The selection of a block is based on a hash of the block's proof-hash and
150 // the previous stake modifier.
151 // Stake modifier is recomputed at a fixed time interval instead of every
152 // block. This is to make it difficult for an attacker to gain control of
153 // additional bits in the stake modifier, even after generating a chain of
155 bool ComputeNextStakeModifier(const CBlockIndex* pindexCurrent, uint64_t& nStakeModifier, bool& fGeneratedStakeModifier)
158 fGeneratedStakeModifier = false;
159 const CBlockIndex* pindexPrev = pindexCurrent->pprev;
162 fGeneratedStakeModifier = true;
163 return true; // genesis block's modifier is 0
166 // First find current stake modifier and its generation block time
167 // if it's not old enough, return the same stake modifier
168 int64_t nModifierTime = 0;
169 if (!GetLastStakeModifier(pindexPrev, nStakeModifier, nModifierTime))
170 return error("ComputeNextStakeModifier: unable to get last modifier");
173 printf("ComputeNextStakeModifier: prev modifier=0x%016" PRIx64 " time=%s epoch=%u\n", nStakeModifier, DateTimeStrFormat(nModifierTime).c_str(), (unsigned int)nModifierTime);
175 if (nModifierTime / nModifierInterval >= pindexPrev->GetBlockTime() / nModifierInterval)
179 printf("ComputeNextStakeModifier: no new interval keep current modifier: pindexPrev nHeight=%d nTime=%u\n", pindexPrev->nHeight, (unsigned int)pindexPrev->GetBlockTime());
183 if (nModifierTime / nModifierInterval >= pindexCurrent->GetBlockTime() / nModifierInterval)
185 // fixed interval protocol requires current block timestamp also be in a different modifier interval
186 if (IsFixedModifierInterval(pindexCurrent->nTime))
190 printf("ComputeNextStakeModifier: no new interval keep current modifier: pindexCurrent nHeight=%d nTime=%u\n", pindexCurrent->nHeight, (unsigned int)pindexCurrent->GetBlockTime());
198 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());
203 // Sort candidate blocks by timestamp
204 vector<pair<int64_t, uint256> > vSortedByTimestamp;
205 vSortedByTimestamp.reserve(64 * nModifierInterval / nStakeTargetSpacing);
206 int64_t nSelectionInterval = GetStakeModifierSelectionInterval();
207 int64_t nSelectionIntervalStart = (pindexPrev->GetBlockTime() / nModifierInterval) * nModifierInterval - nSelectionInterval;
208 const CBlockIndex* pindex = pindexPrev;
209 while (pindex && pindex->GetBlockTime() >= nSelectionIntervalStart)
211 vSortedByTimestamp.push_back(make_pair(pindex->GetBlockTime(), pindex->GetBlockHash()));
212 pindex = pindex->pprev;
214 int nHeightFirstCandidate = pindex ? (pindex->nHeight + 1) : 0;
215 reverse(vSortedByTimestamp.begin(), vSortedByTimestamp.end());
216 sort(vSortedByTimestamp.begin(), vSortedByTimestamp.end());
218 // Select 64 blocks from candidate blocks to generate stake modifier
219 uint64_t nStakeModifierNew = 0;
220 int64_t nSelectionIntervalStop = nSelectionIntervalStart;
221 map<uint256, const CBlockIndex*> mapSelectedBlocks;
222 for (int nRound=0; nRound<min(64, (int)vSortedByTimestamp.size()); nRound++)
224 // add an interval section to the current selection round
225 nSelectionIntervalStop += GetStakeModifierSelectionIntervalSection(nRound);
226 // select a block from the candidates of current round
227 if (!SelectBlockFromCandidates(vSortedByTimestamp, mapSelectedBlocks, nSelectionIntervalStop, nStakeModifier, &pindex))
228 return error("ComputeNextStakeModifier: unable to select block at round %d", nRound);
229 // write the entropy bit of the selected block
230 nStakeModifierNew |= (((uint64_t)pindex->GetStakeEntropyBit()) << nRound);
231 // add the selected block from candidates to selected list
232 mapSelectedBlocks.insert(make_pair(pindex->GetBlockHash(), pindex));
233 if (fDebug && GetBoolArg("-printstakemodifier"))
234 printf("ComputeNextStakeModifier: selected round %d stop=%s height=%d bit=%d\n", nRound, DateTimeStrFormat(nSelectionIntervalStop).c_str(), pindex->nHeight, pindex->GetStakeEntropyBit());
237 // Print selection map for visualization of the selected blocks
238 if (fDebug && GetBoolArg("-printstakemodifier"))
240 string strSelectionMap = "";
241 // '-' indicates proof-of-work blocks not selected
242 strSelectionMap.insert(0, pindexPrev->nHeight - nHeightFirstCandidate + 1, '-');
244 while (pindex && pindex->nHeight >= nHeightFirstCandidate)
246 // '=' indicates proof-of-stake blocks not selected
247 if (pindex->IsProofOfStake())
248 strSelectionMap.replace(pindex->nHeight - nHeightFirstCandidate, 1, "=");
249 pindex = pindex->pprev;
251 BOOST_FOREACH(const PAIRTYPE(uint256, const CBlockIndex*)& item, mapSelectedBlocks)
253 // 'S' indicates selected proof-of-stake blocks
254 // 'W' indicates selected proof-of-work blocks
255 strSelectionMap.replace(item.second->nHeight - nHeightFirstCandidate, 1, item.second->IsProofOfStake()? "S" : "W");
257 printf("ComputeNextStakeModifier: selection height [%d, %d] map %s\n", nHeightFirstCandidate, pindexPrev->nHeight, strSelectionMap.c_str());
261 printf("ComputeNextStakeModifier: new modifier=0x%016" PRIx64 " time=%s\n", nStakeModifierNew, DateTimeStrFormat(pindexPrev->GetBlockTime()).c_str());
264 nStakeModifier = nStakeModifierNew;
265 fGeneratedStakeModifier = true;
269 // The stake modifier used to hash for a stake kernel is chosen as the stake
270 // modifier about a selection interval later than the coin generating the kernel
271 static bool GetKernelStakeModifier(uint256 hashBlockFrom, uint64_t& nStakeModifier, int& nStakeModifierHeight, int64_t& nStakeModifierTime, bool fPrintProofOfStake)
274 if (!mapBlockIndex.count(hashBlockFrom))
275 return error("GetKernelStakeModifier() : block not indexed");
276 const CBlockIndex* pindexFrom = mapBlockIndex[hashBlockFrom];
277 nStakeModifierHeight = pindexFrom->nHeight;
278 nStakeModifierTime = pindexFrom->GetBlockTime();
279 int64_t nStakeModifierSelectionInterval = GetStakeModifierSelectionInterval();
280 const CBlockIndex* pindex = pindexFrom;
281 // loop to find the stake modifier later by a selection interval
282 while (nStakeModifierTime < pindexFrom->GetBlockTime() + nStakeModifierSelectionInterval)
285 { // reached best block; may happen if node is behind on block chain
286 if (fPrintProofOfStake || (pindex->GetBlockTime() + nStakeMinAge - nStakeModifierSelectionInterval > GetAdjustedTime()))
287 return error("GetKernelStakeModifier() : reached best block %s at height %d from block %s",
288 pindex->GetBlockHash().ToString().c_str(), pindex->nHeight, hashBlockFrom.ToString().c_str());
292 pindex = pindex->pnext;
293 if (pindex->GeneratedStakeModifier())
295 nStakeModifierHeight = pindex->nHeight;
296 nStakeModifierTime = pindex->GetBlockTime();
299 nStakeModifier = pindex->nStakeModifier;
303 bool GetKernelStakeModifier(uint256 hashBlockFrom, uint64_t& nStakeModifier)
305 int nStakeModifierHeight;
306 int64_t nStakeModifierTime;
308 return GetKernelStakeModifier(hashBlockFrom, nStakeModifier, nStakeModifierHeight, nStakeModifierTime, false);
312 // ppcoin kernel protocol
313 // coinstake must meet hash target according to the protocol:
314 // kernel (input 0) must meet the formula
315 // hash(nStakeModifier + txPrev.block.nTime + txPrev.offset + txPrev.nTime + txPrev.vout.n + nTime) < bnTarget * nCoinDayWeight
316 // this ensures that the chance of getting a coinstake is proportional to the
317 // amount of coin age one owns.
318 // The reason this hash is chosen is the following:
319 // nStakeModifier: scrambles computation to make it very difficult to precompute
320 // future proof-of-stake at the time of the coin's confirmation
321 // txPrev.block.nTime: prevent nodes from guessing a good timestamp to
322 // generate transaction for future advantage
323 // txPrev.offset: offset of txPrev inside block, to reduce the chance of
324 // nodes generating coinstake at the same time
325 // txPrev.nTime: reduce the chance of nodes generating coinstake at the same
327 // txPrev.vout.n: output number of txPrev, to reduce the chance of nodes
328 // generating coinstake at the same time
329 // block/tx hash should not be used here as they can be generated in vast
330 // quantities so as to generate blocks faster, degrading the system back into
331 // a proof-of-work situation.
333 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)
335 if (nTimeTx < txPrev.nTime) // Transaction timestamp violation
336 return error("CheckStakeKernelHash() : nTime violation");
338 uint32_t nTimeBlockFrom = blockFrom.GetBlockTime();
339 if (nTimeBlockFrom + nStakeMinAge > nTimeTx) // Min age requirement
340 return error("CheckStakeKernelHash() : min age violation");
342 CBigNum bnTargetPerCoinDay;
343 bnTargetPerCoinDay.SetCompact(nBits);
344 int64_t nValueIn = txPrev.vout[prevout.n].nValue;
346 uint256 hashBlockFrom = blockFrom.GetHash();
348 CBigNum bnCoinDayWeight = CBigNum(nValueIn) * GetWeight((int64_t)txPrev.nTime, (int64_t)nTimeTx) / COIN / (24 * 60 * 60);
349 targetProofOfStake = (bnCoinDayWeight * bnTargetPerCoinDay).getuint256();
352 CDataStream ss(SER_GETHASH, 0);
353 uint64_t nStakeModifier = 0;
354 int nStakeModifierHeight = 0;
355 int64_t nStakeModifierTime = 0;
357 if (!GetKernelStakeModifier(hashBlockFrom, nStakeModifier, nStakeModifierHeight, nStakeModifierTime, fPrintProofOfStake))
359 ss << nStakeModifier;
361 ss << nTimeBlockFrom << nTxPrevOffset << txPrev.nTime << prevout.n << nTimeTx;
362 hashProofOfStake = Hash(ss.begin(), ss.end());
363 if (fPrintProofOfStake)
365 printf("CheckStakeKernelHash() : using modifier 0x%016" PRIx64 " at height=%d timestamp=%s for block from height=%d timestamp=%s\n",
366 nStakeModifier, nStakeModifierHeight,
367 DateTimeStrFormat(nStakeModifierTime).c_str(),
368 mapBlockIndex[hashBlockFrom]->nHeight,
369 DateTimeStrFormat(blockFrom.GetBlockTime()).c_str());
370 printf("CheckStakeKernelHash() : check modifier=0x%016" PRIx64 " nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashProof=%s\n",
372 nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx,
373 hashProofOfStake.ToString().c_str());
376 // Now check if proof-of-stake hash meets target protocol
377 if (CBigNum(hashProofOfStake) > bnCoinDayWeight * bnTargetPerCoinDay)
379 if (fDebug && !fPrintProofOfStake)
381 printf("CheckStakeKernelHash() : using modifier 0x%016" PRIx64 " at height=%d timestamp=%s for block from height=%d timestamp=%s\n",
382 nStakeModifier, nStakeModifierHeight,
383 DateTimeStrFormat(nStakeModifierTime).c_str(),
384 mapBlockIndex[hashBlockFrom]->nHeight,
385 DateTimeStrFormat(blockFrom.GetBlockTime()).c_str());
386 printf("CheckStakeKernelHash() : pass modifier=0x%016" PRIx64 " nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashProof=%s\n",
388 nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx,
389 hashProofOfStake.ToString().c_str());
394 // Scan given coins set for kernel solution
395 bool ScanForStakeKernelHash(MetaMap &mapMeta, KernelSearchSettings &settings, CoinsSet::value_type &kernelcoin, uint32_t &nTimeTx, uint32_t &nBlockTime, uint64_t &nKernelsTried, uint64_t &nCoinDaysTried)
397 uint256 hashProofOfStake = 0;
399 // (txid, vout.n) => ((txindex, (tx, vout.n)), (block, modifier))
400 for(MetaMap::const_iterator meta_item = mapMeta.begin(); meta_item != mapMeta.end(); meta_item++)
402 if (!fCoinsDataActual)
405 CTxIndex txindex = (*meta_item).second.first.first;
406 CBlock block = (*meta_item).second.second.first;
407 uint64_t nStakeModifier = (*meta_item).second.second.second;
410 CoinsSet::value_type pcoin = meta_item->second.first.second;
412 static int nMaxStakeSearchInterval = 60;
414 // only count coins meeting min age requirement
415 if (nStakeMinAge + block.nTime > settings.nTime - nMaxStakeSearchInterval)
418 // Transaction offset inside block
419 uint32_t nTxOffset = txindex.pos.nTxPos - txindex.pos.nBlockPos;
421 // Current timestamp scanning interval
422 unsigned int nCurrentSearchInterval = min((int64_t)settings.nSearchInterval, (int64_t)nMaxStakeSearchInterval);
424 nBlockTime = block.nTime;
425 CBigNum bnTargetPerCoinDay;
426 bnTargetPerCoinDay.SetCompact(settings.nBits);
427 int64_t nValueIn = pcoin.first->vout[pcoin.second].nValue;
429 // Search backward in time from the given timestamp
430 // Search nSearchInterval seconds back up to nMaxStakeSearchInterval
431 // Stopping search in case of shutting down or cache invalidation
432 for (unsigned int n=0; n<nCurrentSearchInterval && fCoinsDataActual && !fShutdown; n++)
434 nTimeTx = settings.nTime - n;
435 CBigNum bnCoinDayWeight = CBigNum(nValueIn) * GetWeight((int64_t)pcoin.first->nTime, (int64_t)nTimeTx) / COIN / (24 * 60 * 60);
436 CBigNum bnTargetProofOfStake = bnCoinDayWeight * bnTargetPerCoinDay;
439 CDataStream ss(SER_GETHASH, 0);
440 ss << nStakeModifier;
441 ss << nBlockTime << nTxOffset << pcoin.first->nTime << pcoin.second << nTimeTx;
443 // Calculate kernel hash
444 hashProofOfStake = Hash(ss.begin(), ss.end());
448 nCoinDaysTried += bnCoinDayWeight.getuint64();
450 if (bnTargetProofOfStake >= CBigNum(hashProofOfStake))
453 printf("nStakeModifier=0x%016" PRIx64 ", nBlockTime=%u nTxOffset=%u nTxPrevTime=%u nVout=%u nTimeTx=%u hashProofOfStake=%s Success=true\n",
454 nStakeModifier, nBlockTime, nTxOffset, pcoin.first->nTime, pcoin.second, nTimeTx, hashProofOfStake.GetHex().c_str());
461 printf("nStakeModifier=0x%016" PRIx64 ", nBlockTime=%u nTxOffset=%u nTxPrevTime=%u nTxNumber=%u nTimeTx=%u hashProofOfStake=%s Success=false\n",
462 nStakeModifier, nBlockTime, nTxOffset, pcoin.first->nTime, pcoin.second, nTimeTx, hashProofOfStake.GetHex().c_str());
469 // Check kernel hash target and coinstake signature
470 bool CheckProofOfStake(const CTransaction& tx, unsigned int nBits, uint256& hashProofOfStake, uint256& targetProofOfStake)
472 if (!tx.IsCoinStake())
473 return error("CheckProofOfStake() : called on non-coinstake %s", tx.GetHash().ToString().c_str());
475 // Kernel (input 0) must match the stake hash target per coin age (nBits)
476 const CTxIn& txin = tx.vin[0];
478 // First try finding the previous transaction in database
482 if (!txPrev.ReadFromDisk(txdb, txin.prevout, txindex))
483 return tx.DoS(1, error("CheckProofOfStake() : INFO: read txPrev failed")); // previous transaction not in main chain, may occur during initial download
490 if (!VerifySignature(txPrev, tx, 0, MANDATORY_SCRIPT_VERIFY_FLAGS, 0))
491 return tx.DoS(100, error("CheckProofOfStake() : VerifySignature failed on coinstake %s", tx.GetHash().ToString().c_str()));
495 if (!block.ReadFromDisk(txindex.pos.nFile, txindex.pos.nBlockPos, false))
496 return fDebug? error("CheckProofOfStake() : read block failed") : false; // unable to read block of previous transaction
498 if (!CheckStakeKernelHash(nBits, block, txindex.pos.nTxPos - txindex.pos.nBlockPos, txPrev, txin.prevout, tx.nTime, hashProofOfStake, targetProofOfStake, fDebug))
499 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
504 // Get stake modifier checksum
505 uint32_t GetStakeModifierChecksum(const CBlockIndex* pindex)
507 assert (pindex->pprev || pindex->GetBlockHash() == (!fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet));
508 // Hash previous checksum with flags, hashProofOfStake and nStakeModifier
509 CDataStream ss(SER_GETHASH, 0);
511 ss << pindex->pprev->nStakeModifierChecksum;
512 ss << pindex->nFlags << pindex->hashProofOfStake << pindex->nStakeModifier;
513 uint256 hashChecksum = Hash(ss.begin(), ss.end());
514 hashChecksum >>= (256 - 32);
515 return hashChecksum.Get64();
518 // Check stake modifier hard checkpoints
519 bool CheckStakeModifierCheckpoints(int nHeight, uint32_t nStakeModifierChecksum)
521 MapModifierCheckpoints& checkpoints = (fTestNet ? mapStakeModifierCheckpointsTestNet : mapStakeModifierCheckpoints);
523 if (checkpoints.count(nHeight))
524 return nStakeModifierChecksum == checkpoints[nHeight];