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
31 ( 12661, 0x5d84115du )
32 (143990, 0x9c592c78u )
33 (149000, 0x48f2bdc4u )
34 (160000, 0x789df0f0u )
35 (200000, 0x01ec1503u )
38 // Hard checkpoints of stake modifiers to ensure they are deterministic (testNet)
39 static std::map<int, unsigned int> mapStakeModifierCheckpointsTestNet =
40 boost::assign::map_list_of
44 // Pregenerated entropy bits table (from genesis to #9689)
46 // Bits are packed into array of 256 bit integers:
48 // * array index calculated as nHeight / 256
49 // * position of bit is calculated as nHeight & 0xFF.
51 const uint256 entropyStore[] = {
52 uint256("0x4555b4dcc1d690ddd9b810c90c66e82b18bf4f43cc887246c418383ec120a5ab"),
53 uint256("0xaa6d1198412fa77608addf6549c9198a22155e8afd7a9ded6179f6b7cfc66b0c"),
54 uint256("0x9442fabfa4116fb14a9769c2eea003845a1f5c3a0260f36b497d68f3a3cd4078"),
55 uint256("0x0e769042a9a98e42388195d699574b822d06515f7053ad884c53d7ee059f05b1"),
56 uint256("0x7005aac20baf70251aebfe3f1b95987d83ef1e3e6963de8fed601d4dd07bf7cf"),
57 uint256("0x58952c5c3de188f2e33c38d3f53d7bf44f9bc545a4289d266696273fa821be66"),
58 uint256("0x50b6c2ed780c08aaec3f7665b1b6004206243e3866456fc910b83b52d07eeb63"),
59 uint256("0x563841eefca85ba3384986c58100408ae3f1ba2ac727e1ac910ce154a06c702f"),
60 uint256("0x79275b03938b3e27a9b01a7f7953c6c487c58355f5d4169accfbb800213ffd13"),
61 uint256("0xd783f2538b3ed18f135af90adc687c5646d93aeaeaabc6667be94f7aa0a2d366"),
62 uint256("0xb441d0c175c40c8e88b09d88ea008af79cbed2d28219427d2e72fda682974db8"),
63 uint256("0x3204c43bd41f2e19628af3b0c9aca3db15bca4c8705d51056e7b17a319c04715"),
64 uint256("0x7e80e6ab7857d8f2f261a0a49c783bd800b365b8c9b85cc0e13f73904b0dcaa9"),
65 uint256("0xefaaee60ed82d2ad145c0e347941fdb131eb8fd289a45eef07121a93f283c5f1"),
66 uint256("0x3efc86e4334da332c1fd4c12513c40cff689f3efdc7f9913230822adacdda4f9"),
67 uint256("0xf0d6b8f38599a017fa35d1fbbf9ef51eca5ebc5b286aadba40c4c3e1d9bace0c"),
68 uint256("0x286a67f27323486036a0a92d35382fc8963c0c00bad331723318b4b9fdb2b56e"),
69 uint256("0xecbfaaa6567c54f08c4d5bd0118a2d7b58740f42cbfc73aa1536c1f5f76de87c"),
70 uint256("0xf9a4de1c5c46520de5aaf10d3796cf0e27ddce98b3398357f5726a949664e308"),
71 uint256("0xd75e6c4dc4be08401e3478d2467d9ab96a62af4f255c04a82c41af0de0a487bb"),
72 uint256("0x1a82c3bc6ad6047294c16571b5e2b7316c97bf8813e7da15798b9820d67e39f2"),
73 uint256("0xb49be0080de564e01829ded7e7971979565a741c5975dc9978dcc020192d396c"),
74 uint256("0x0d8eed113be67663b5a15a0625a9b49792b5ea59c005c4f405914877acab7000"),
75 uint256("0x8f9d46e2bc05a218ffa942965b747056197d393b097085523640cd59e07fe7c7"),
76 uint256("0x7a63ab40bc7f40ac2ebe9ede438d97b45fa6ed6f8419016da8d5f7a670111dda"),
77 uint256("0x63fbcc080448c43d6cf915c958314feff7a95a52ba43a68c05fc281d3a522d25"),
78 uint256("0xf834cf824c326d3ea861ea1e85dc3289265e37045981e28208e7344a7f8081d7"),
79 uint256("0xb4edc22ec98cc49b2f5af5bae3f52f5e6058280f74f2c432c2dd89ae49acceb8"),
80 uint256("0x0fe596037dcf81bf5c64f39755261c404ed088af5c8c31dd7549b6657ee92365"),
81 uint256("0xbbad51a0aeba254b01d18c328de9e932b9b859b61e622c325d64e2211b5e413d"),
82 uint256("0xabf0194cc787be938bc51c7fdf1cae4ec79e65ebab8fa8b8f40541c44ef384b0"),
83 uint256("0x83bc12d6fdbd3e854cb91c4ca7dfba3c38e8714121af88c8a8abdb33e5002438"),
84 uint256("0x71a2513026cabaedcbe55aeb6dc8049e5b763a3f54f10c33dd333624f764b38c"),
85 uint256("0xee6725632ff5c025dff6a18cd059875dcae20f399b03bccba13d9d5fcf6d9d9a"),
86 uint256("0xa168a2741d1e7e50cc74b79f695c25ffd3576e6bd61353c2a20e569fd63b2dac"),
87 uint256("0x6e462d2a87bfde9398b6747f94a8ed6a01e4d96c5b4372df5c910c106c48bd13"),
88 uint256("0x8eeb696181957c4b22434028990f49cb30006827c73860e77e2eecf5c38be99d"),
89 uint256("0x3188aaa65877b166f05cdc48f55b1f77a7d6fb221c395596d990ae5647e9ba96")
92 // Whether the given block is subject to new modifier protocol
93 bool IsFixedModifierInterval(unsigned int nTimeBlock)
95 return (nTimeBlock >= (fTestNet? nModifierTestSwitchTime : nModifierSwitchTime));
98 // Get the last stake modifier and its generation time from a given block
99 static bool GetLastStakeModifier(const CBlockIndex* pindex, uint64_t& nStakeModifier, int64_t& nModifierTime)
102 return error("GetLastStakeModifier: null pindex");
103 while (pindex && pindex->pprev && !pindex->GeneratedStakeModifier())
104 pindex = pindex->pprev;
105 if (!pindex->GeneratedStakeModifier())
106 return error("GetLastStakeModifier: no generation at genesis block");
107 nStakeModifier = pindex->nStakeModifier;
108 nModifierTime = pindex->GetBlockTime();
112 // Get selection interval section (in seconds)
113 static int64_t GetStakeModifierSelectionIntervalSection(int nSection)
115 assert (nSection >= 0 && nSection < 64);
116 return (nModifierInterval * 63 / (63 + ((63 - nSection) * (MODIFIER_INTERVAL_RATIO - 1))));
119 // Get stake modifier selection interval (in seconds)
120 static int64_t GetStakeModifierSelectionInterval()
122 int64_t nSelectionInterval = 0;
123 for (int nSection=0; nSection<64; nSection++)
124 nSelectionInterval += GetStakeModifierSelectionIntervalSection(nSection);
125 return nSelectionInterval;
128 // select a block from the candidate blocks in vSortedByTimestamp, excluding
129 // already selected blocks in vSelectedBlocks, and with timestamp up to
130 // nSelectionIntervalStop.
131 static bool SelectBlockFromCandidates(vector<pair<int64_t, uint256> >& vSortedByTimestamp, map<uint256, const CBlockIndex*>& mapSelectedBlocks,
132 int64_t nSelectionIntervalStop, uint64_t nStakeModifierPrev, const CBlockIndex** pindexSelected)
134 bool fSelected = false;
135 uint256 hashBest = 0;
136 *pindexSelected = (const CBlockIndex*) 0;
137 BOOST_FOREACH(const PAIRTYPE(int64_t, uint256)& item, vSortedByTimestamp)
139 if (!mapBlockIndex.count(item.second))
140 return error("SelectBlockFromCandidates: failed to find block index for candidate block %s", item.second.ToString().c_str());
141 const CBlockIndex* pindex = mapBlockIndex[item.second];
142 if (fSelected && pindex->GetBlockTime() > nSelectionIntervalStop)
144 if (mapSelectedBlocks.count(pindex->GetBlockHash()) > 0)
146 // compute the selection hash by hashing its proof-hash and the
147 // previous proof-of-stake modifier
148 uint256 hashProof = pindex->IsProofOfStake()? pindex->hashProofOfStake : pindex->GetBlockHash();
149 CDataStream ss(SER_GETHASH, 0);
150 ss << hashProof << nStakeModifierPrev;
151 uint256 hashSelection = Hash(ss.begin(), ss.end());
152 // the selection hash is divided by 2**32 so that proof-of-stake block
153 // is always favored over proof-of-work block. this is to preserve
154 // the energy efficiency property
155 if (pindex->IsProofOfStake())
156 hashSelection >>= 32;
157 if (fSelected && hashSelection < hashBest)
159 hashBest = hashSelection;
160 *pindexSelected = (const CBlockIndex*) pindex;
165 hashBest = hashSelection;
166 *pindexSelected = (const CBlockIndex*) pindex;
169 if (fDebug && GetBoolArg("-printstakemodifier"))
170 printf("SelectBlockFromCandidates: selection hash=%s\n", hashBest.ToString().c_str());
174 // Stake Modifier (hash modifier of proof-of-stake):
175 // The purpose of stake modifier is to prevent a txout (coin) owner from
176 // computing future proof-of-stake generated by this txout at the time
177 // of transaction confirmation. To meet kernel protocol, the txout
178 // must hash with a future stake modifier to generate the proof.
179 // Stake modifier consists of bits each of which is contributed from a
180 // selected block of a given block group in the past.
181 // The selection of a block is based on a hash of the block's proof-hash and
182 // the previous stake modifier.
183 // Stake modifier is recomputed at a fixed time interval instead of every
184 // block. This is to make it difficult for an attacker to gain control of
185 // additional bits in the stake modifier, even after generating a chain of
187 bool ComputeNextStakeModifier(const CBlockIndex* pindexCurrent, uint64_t& nStakeModifier, bool& fGeneratedStakeModifier)
190 fGeneratedStakeModifier = false;
191 const CBlockIndex* pindexPrev = pindexCurrent->pprev;
194 fGeneratedStakeModifier = true;
195 return true; // genesis block's modifier is 0
198 // First find current stake modifier and its generation block time
199 // if it's not old enough, return the same stake modifier
200 int64_t nModifierTime = 0;
201 if (!GetLastStakeModifier(pindexPrev, nStakeModifier, nModifierTime))
202 return error("ComputeNextStakeModifier: unable to get last modifier");
205 printf("ComputeNextStakeModifier: prev modifier=0x%016" PRIx64 " time=%s epoch=%u\n", nStakeModifier, DateTimeStrFormat(nModifierTime).c_str(), (unsigned int)nModifierTime);
207 if (nModifierTime / nModifierInterval >= pindexPrev->GetBlockTime() / nModifierInterval)
211 printf("ComputeNextStakeModifier: no new interval keep current modifier: pindexPrev nHeight=%d nTime=%u\n", pindexPrev->nHeight, (unsigned int)pindexPrev->GetBlockTime());
215 if (nModifierTime / nModifierInterval >= pindexCurrent->GetBlockTime() / nModifierInterval)
217 // fixed interval protocol requires current block timestamp also be in a different modifier interval
218 if (IsFixedModifierInterval(pindexCurrent->nTime))
222 printf("ComputeNextStakeModifier: no new interval keep current modifier: pindexCurrent nHeight=%d nTime=%u\n", pindexCurrent->nHeight, (unsigned int)pindexCurrent->GetBlockTime());
230 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());
235 // Sort candidate blocks by timestamp
236 vector<pair<int64_t, uint256> > vSortedByTimestamp;
237 vSortedByTimestamp.reserve(64 * nModifierInterval / nStakeTargetSpacing);
238 int64_t nSelectionInterval = GetStakeModifierSelectionInterval();
239 int64_t nSelectionIntervalStart = (pindexPrev->GetBlockTime() / nModifierInterval) * nModifierInterval - nSelectionInterval;
240 const CBlockIndex* pindex = pindexPrev;
241 while (pindex && pindex->GetBlockTime() >= nSelectionIntervalStart)
243 vSortedByTimestamp.push_back(make_pair(pindex->GetBlockTime(), pindex->GetBlockHash()));
244 pindex = pindex->pprev;
246 int nHeightFirstCandidate = pindex ? (pindex->nHeight + 1) : 0;
247 reverse(vSortedByTimestamp.begin(), vSortedByTimestamp.end());
248 sort(vSortedByTimestamp.begin(), vSortedByTimestamp.end());
250 // Select 64 blocks from candidate blocks to generate stake modifier
251 uint64_t nStakeModifierNew = 0;
252 int64_t nSelectionIntervalStop = nSelectionIntervalStart;
253 map<uint256, const CBlockIndex*> mapSelectedBlocks;
254 for (int nRound=0; nRound<min(64, (int)vSortedByTimestamp.size()); nRound++)
256 // add an interval section to the current selection round
257 nSelectionIntervalStop += GetStakeModifierSelectionIntervalSection(nRound);
258 // select a block from the candidates of current round
259 if (!SelectBlockFromCandidates(vSortedByTimestamp, mapSelectedBlocks, nSelectionIntervalStop, nStakeModifier, &pindex))
260 return error("ComputeNextStakeModifier: unable to select block at round %d", nRound);
261 // write the entropy bit of the selected block
262 nStakeModifierNew |= (((uint64_t)pindex->GetStakeEntropyBit()) << nRound);
263 // add the selected block from candidates to selected list
264 mapSelectedBlocks.insert(make_pair(pindex->GetBlockHash(), pindex));
265 if (fDebug && GetBoolArg("-printstakemodifier"))
266 printf("ComputeNextStakeModifier: selected round %d stop=%s height=%d bit=%d\n", nRound, DateTimeStrFormat(nSelectionIntervalStop).c_str(), pindex->nHeight, pindex->GetStakeEntropyBit());
269 // Print selection map for visualization of the selected blocks
270 if (fDebug && GetBoolArg("-printstakemodifier"))
272 string strSelectionMap = "";
273 // '-' indicates proof-of-work blocks not selected
274 strSelectionMap.insert(0, pindexPrev->nHeight - nHeightFirstCandidate + 1, '-');
276 while (pindex && pindex->nHeight >= nHeightFirstCandidate)
278 // '=' indicates proof-of-stake blocks not selected
279 if (pindex->IsProofOfStake())
280 strSelectionMap.replace(pindex->nHeight - nHeightFirstCandidate, 1, "=");
281 pindex = pindex->pprev;
283 BOOST_FOREACH(const PAIRTYPE(uint256, const CBlockIndex*)& item, mapSelectedBlocks)
285 // 'S' indicates selected proof-of-stake blocks
286 // 'W' indicates selected proof-of-work blocks
287 strSelectionMap.replace(item.second->nHeight - nHeightFirstCandidate, 1, item.second->IsProofOfStake()? "S" : "W");
289 printf("ComputeNextStakeModifier: selection height [%d, %d] map %s\n", nHeightFirstCandidate, pindexPrev->nHeight, strSelectionMap.c_str());
293 printf("ComputeNextStakeModifier: new modifier=0x%016" PRIx64 " time=%s\n", nStakeModifierNew, DateTimeStrFormat(pindexPrev->GetBlockTime()).c_str());
296 nStakeModifier = nStakeModifierNew;
297 fGeneratedStakeModifier = true;
301 // The stake modifier used to hash for a stake kernel is chosen as the stake
302 // modifier about a selection interval later than the coin generating the kernel
303 static bool GetKernelStakeModifier(uint256 hashBlockFrom, uint64_t& nStakeModifier, int& nStakeModifierHeight, int64_t& nStakeModifierTime, bool fPrintProofOfStake)
306 if (!mapBlockIndex.count(hashBlockFrom))
307 return error("GetKernelStakeModifier() : block not indexed");
308 const CBlockIndex* pindexFrom = mapBlockIndex[hashBlockFrom];
309 nStakeModifierHeight = pindexFrom->nHeight;
310 nStakeModifierTime = pindexFrom->GetBlockTime();
311 int64_t nStakeModifierSelectionInterval = GetStakeModifierSelectionInterval();
312 const CBlockIndex* pindex = pindexFrom;
313 // loop to find the stake modifier later by a selection interval
314 while (nStakeModifierTime < pindexFrom->GetBlockTime() + nStakeModifierSelectionInterval)
317 { // reached best block; may happen if node is behind on block chain
318 if (fPrintProofOfStake || (pindex->GetBlockTime() + nStakeMinAge - nStakeModifierSelectionInterval > GetAdjustedTime()))
319 return error("GetKernelStakeModifier() : reached best block %s at height %d from block %s",
320 pindex->GetBlockHash().ToString().c_str(), pindex->nHeight, hashBlockFrom.ToString().c_str());
324 pindex = pindex->pnext;
325 if (pindex->GeneratedStakeModifier())
327 nStakeModifierHeight = pindex->nHeight;
328 nStakeModifierTime = pindex->GetBlockTime();
331 nStakeModifier = pindex->nStakeModifier;
335 bool GetKernelStakeModifier(uint256 hashBlockFrom, uint64_t& nStakeModifier)
337 int nStakeModifierHeight;
338 int64_t nStakeModifierTime;
340 return GetKernelStakeModifier(hashBlockFrom, nStakeModifier, nStakeModifierHeight, nStakeModifierTime, false);
344 // ppcoin kernel protocol
345 // coinstake must meet hash target according to the protocol:
346 // kernel (input 0) must meet the formula
347 // hash(nStakeModifier + txPrev.block.nTime + txPrev.offset + txPrev.nTime + txPrev.vout.n + nTime) < bnTarget * nCoinDayWeight
348 // this ensures that the chance of getting a coinstake is proportional to the
349 // amount of coin age one owns.
350 // The reason this hash is chosen is the following:
351 // nStakeModifier: scrambles computation to make it very difficult to precompute
352 // future proof-of-stake at the time of the coin's confirmation
353 // txPrev.block.nTime: prevent nodes from guessing a good timestamp to
354 // generate transaction for future advantage
355 // txPrev.offset: offset of txPrev inside block, to reduce the chance of
356 // nodes generating coinstake at the same time
357 // txPrev.nTime: reduce the chance of nodes generating coinstake at the same
359 // txPrev.vout.n: output number of txPrev, to reduce the chance of nodes
360 // generating coinstake at the same time
361 // block/tx hash should not be used here as they can be generated in vast
362 // quantities so as to generate blocks faster, degrading the system back into
363 // a proof-of-work situation.
365 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)
367 if (nTimeTx < txPrev.nTime) // Transaction timestamp violation
368 return error("CheckStakeKernelHash() : nTime violation");
370 uint32_t nTimeBlockFrom = blockFrom.GetBlockTime();
371 if (nTimeBlockFrom + nStakeMinAge > nTimeTx) // Min age requirement
372 return error("CheckStakeKernelHash() : min age violation");
374 CBigNum bnTargetPerCoinDay;
375 bnTargetPerCoinDay.SetCompact(nBits);
376 int64_t nValueIn = txPrev.vout[prevout.n].nValue;
378 uint256 hashBlockFrom = blockFrom.GetHash();
380 CBigNum bnCoinDayWeight = CBigNum(nValueIn) * GetWeight((int64_t)txPrev.nTime, (int64_t)nTimeTx) / COIN / nOneDay;
381 targetProofOfStake = (bnCoinDayWeight * bnTargetPerCoinDay).getuint256();
384 CDataStream ss(SER_GETHASH, 0);
385 uint64_t nStakeModifier = 0;
386 int nStakeModifierHeight = 0;
387 int64_t nStakeModifierTime = 0;
389 if (!GetKernelStakeModifier(hashBlockFrom, nStakeModifier, nStakeModifierHeight, nStakeModifierTime, fPrintProofOfStake))
391 ss << nStakeModifier;
393 ss << nTimeBlockFrom << nTxPrevOffset << txPrev.nTime << prevout.n << nTimeTx;
394 hashProofOfStake = Hash(ss.begin(), ss.end());
395 if (fPrintProofOfStake)
397 printf("CheckStakeKernelHash() : using modifier 0x%016" PRIx64 " at height=%d timestamp=%s for block from height=%d timestamp=%s\n",
398 nStakeModifier, nStakeModifierHeight,
399 DateTimeStrFormat(nStakeModifierTime).c_str(),
400 mapBlockIndex[hashBlockFrom]->nHeight,
401 DateTimeStrFormat(blockFrom.GetBlockTime()).c_str());
402 printf("CheckStakeKernelHash() : check modifier=0x%016" PRIx64 " nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashTarget=%s hashProof=%s\n",
404 nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx,
405 targetProofOfStake.ToString().c_str(), hashProofOfStake.ToString().c_str());
408 // Now check if proof-of-stake hash meets target protocol
409 if (CBigNum(hashProofOfStake) > bnCoinDayWeight * bnTargetPerCoinDay)
411 if (fDebug && !fPrintProofOfStake)
413 printf("CheckStakeKernelHash() : using modifier 0x%016" PRIx64 " at height=%d timestamp=%s for block from height=%d timestamp=%s\n",
414 nStakeModifier, nStakeModifierHeight,
415 DateTimeStrFormat(nStakeModifierTime).c_str(),
416 mapBlockIndex[hashBlockFrom]->nHeight,
417 DateTimeStrFormat(blockFrom.GetBlockTime()).c_str());
418 printf("CheckStakeKernelHash() : pass modifier=0x%016" PRIx64 " nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashTarget=%s hashProof=%s\n",
420 nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx,
421 targetProofOfStake.ToString().c_str(), hashProofOfStake.ToString().c_str());
430 static const uint32_t block1_suffix[9] = { 0x80000000, 0, 0, 0, 0, 0, 0, 0, 0xe0000000 };
431 static const uint32_t block1_suffix_4way[4 * 9] = {
432 0x00000080, 0x00000080, 0x00000080, 0x00000080,
440 0xe0000000, 0xe0000000, 0xe0000000, 0xe0000000
444 static const uint32_t block2_suffix[8] = { 0x80000000, 0, 0, 0, 0, 0, 0, 0x00010000 };
445 static const uint32_t block2_suffix_4way[4 * 8] = {
446 0x00000080, 0x00000080, 0x00000080, 0x00000080,
453 0x00010000, 0x00010000, 0x00010000, 0x00010000
456 extern "C" int sha256_use_4way();
458 extern "C" void sha256_init(uint32_t *state);
459 extern "C" void sha256_transform(uint32_t *state, const uint32_t *block, int swap);
461 extern "C" void sha256_init_4way(uint32_t *state);
462 extern "C" void sha256_transform_4way(uint32_t *state, const uint32_t *block, int swap);
464 bool fUse4Way = sha256_use_4way() != 0;
466 class ScanMidstateWorker
471 ScanMidstateWorker(unsigned char *kernel, uint32_t nBits, uint32_t nInputTxTime, int64_t nValueIn, uint32_t nIntervalBegin, uint32_t nIntervalEnd)
472 : kernel(kernel), nBits(nBits), nInputTxTime(nInputTxTime), bnValueIn(nValueIn), nIntervalBegin(nIntervalBegin), nIntervalEnd(nIntervalEnd)
474 solutions = vector<std::pair<uint256,uint32_t> >();
479 SetThreadPriority(THREAD_PRIORITY_LOWEST);
481 // Compute maximum possible target to filter out majority of obviously insufficient hashes
482 CBigNum bnTargetPerCoinDay;
483 bnTargetPerCoinDay.SetCompact(nBits);
484 uint256 nMaxTarget = (bnTargetPerCoinDay * bnValueIn * nStakeMaxAge / COIN / nOneDay).getuint256();
486 uint32_t state1[4 * 8] __attribute__((aligned(16)));
487 uint32_t state2[4 * 8] __attribute__((aligned(16)));
488 uint32_t blocks1[4 * 16] __attribute__((aligned(16)));
489 uint32_t blocks2[4 * 16] __attribute__((aligned(16)));
491 vector<uint32_t> vRow = vector<uint32_t>(4);
492 uint32_t *pnKernel = (uint32_t *) kernel;
494 for(int i = 0; i < 7; i++)
496 uint32_t nVal = pnKernel[i];
497 fill(vRow.begin(), vRow.end(), nVal);
499 for (int j = 0; j < 4; j++)
501 memcpy(&blocks1[i*4], &vRow[0], 16);
505 memcpy(&blocks1[28], &block1_suffix_4way[0], 36*4); // sha256 padding
506 memcpy(&blocks2[32], &block2_suffix_4way[0], 32*4);
508 // Search forward in time from the given timestamp
509 // Stopping search in case of shutting down
510 for (uint32_t nTimeTx=nIntervalBegin, nMaxTarget32 = nMaxTarget.Get32(7); nTimeTx<nIntervalEnd && !fShutdown; )
512 sha256_init_4way(state1);
513 sha256_init_4way(state2);
515 blocks1[24] = nTimeTx++;
516 blocks1[25] = nTimeTx++;
517 blocks1[26] = nTimeTx++;
518 blocks1[27] = nTimeTx++;
520 sha256_transform_4way(&state1[0], &blocks1[0], 1); // first hashing
522 for(int i=0; i<32; i++)
523 blocks2[i] = __builtin_bswap32(state1[i]);
525 sha256_transform_4way(&state2[0], &blocks2[0], 1); // second hashing
527 for(int nResult = 0; nResult < 4; nResult++)
529 uint32_t nHash = __builtin_bswap32(state2[28+nResult]);
531 if (nHash <= nMaxTarget32) // Possible hit
533 uint32_t nTime = blocks1[24+nResult];
534 uint256 nHashProofOfStake = 0;
535 uint32_t *pnHashProofOfStake = (uint32_t *) &nHashProofOfStake;
536 pnHashProofOfStake[7] = nHash;
538 for (int i = 0; i < 7; i++)
539 pnHashProofOfStake[i] = __builtin_bswap32(state2[(i*4) + nResult]);
541 CBigNum bnCoinDayWeight = bnValueIn * GetWeight((int64_t)nInputTxTime, (int64_t)nTimeTx) / COIN / nOneDay;
542 CBigNum bnTargetProofOfStake = bnCoinDayWeight * bnTargetPerCoinDay;
544 if (bnTargetProofOfStake >= CBigNum(nHashProofOfStake))
545 solutions.push_back(std::pair<uint256,uint32_t>(nHashProofOfStake, nTime));
553 SetThreadPriority(THREAD_PRIORITY_LOWEST);
555 // Init new sha256 context and update it
556 // with first 24 bytes of kernel
557 SHA256_CTX workerCtx;
558 SHA256_Init(&workerCtx);
559 SHA256_Update(&workerCtx, kernel, 8 + 16);
560 SHA256_CTX ctx = workerCtx;
562 // Sha256 result buffer
563 uint32_t hashProofOfStake[8];
565 // Compute maximum possible target to filter out majority of obviously insufficient hashes
566 CBigNum bnTargetPerCoinDay;
567 bnTargetPerCoinDay.SetCompact(nBits);
569 uint256 nMaxTarget = (bnTargetPerCoinDay * bnValueIn * nStakeMaxAge / COIN / nOneDay).getuint256(),
570 *pnHashProofOfStake = (uint256 *)&hashProofOfStake;
572 // Search forward in time from the given timestamp
573 // Stopping search in case of shutting down
574 for (uint32_t nTimeTx=nIntervalBegin, nMaxTarget32 = nMaxTarget.Get32(7); nTimeTx<nIntervalEnd && !fShutdown; nTimeTx++)
576 // Complete first hashing iteration
578 SHA256_Update(&ctx, (unsigned char*)&nTimeTx, 4);
579 SHA256_Final((unsigned char*)&hash1, &ctx);
584 // Finally, calculate kernel hash
585 SHA256((unsigned char*)&hash1, sizeof(hashProofOfStake), (unsigned char*)&hashProofOfStake);
587 // Skip if hash doesn't satisfy the maximum target
588 if (hashProofOfStake[7] > nMaxTarget32)
591 CBigNum bnCoinDayWeight = bnValueIn * GetWeight((int64_t)nInputTxTime, (int64_t)nTimeTx) / COIN / nOneDay;
592 CBigNum bnTargetProofOfStake = bnCoinDayWeight * bnTargetPerCoinDay;
594 if (bnTargetProofOfStake >= CBigNum(*pnHashProofOfStake))
595 solutions.push_back(std::pair<uint256,uint32_t>(*pnHashProofOfStake, nTimeTx));
607 vector<std::pair<uint256,uint32_t> >& GetSolutions()
613 std::vector<std::pair<uint256,uint32_t> > solutions;
617 uint32_t nInputTxTime;
619 uint32_t nIntervalBegin;
620 uint32_t nIntervalEnd;
624 class ScanMidstateWorker
629 ScanMidstateWorker(unsigned char *kernel, uint32_t nBits, uint32_t nInputTxTime, int64_t nValueIn, uint32_t nIntervalBegin, uint32_t nIntervalEnd)
630 : nBits(nBits), nInputTxTime(nInputTxTime), bnValueIn(nValueIn), nIntervalBegin(nIntervalBegin), nIntervalEnd(nIntervalEnd)
632 // Init new sha256 context and update it
633 // with first 24 bytes of kernel
634 SHA256_Init(&workerCtx);
635 SHA256_Update(&workerCtx, kernel, 8 + 16);
636 solutions = vector<std::pair<uint256,uint32_t> >();
641 SetThreadPriority(THREAD_PRIORITY_LOWEST);
642 SHA256_CTX ctx = workerCtx;
644 // Sha256 result buffer
645 uint32_t hashProofOfStake[8];
647 // Compute maximum possible target to filter out majority of obviously insufficient hashes
648 CBigNum bnTargetPerCoinDay;
649 bnTargetPerCoinDay.SetCompact(nBits);
651 uint256 nMaxTarget = (bnTargetPerCoinDay * bnValueIn * nStakeMaxAge / COIN / nOneDay).getuint256(),
652 *pnHashProofOfStake = (uint256 *)&hashProofOfStake;
654 // Search forward in time from the given timestamp
655 // Stopping search in case of shutting down
656 for (uint32_t nTimeTx=nIntervalBegin, nMaxTarget32 = nMaxTarget.Get32(7); nTimeTx<nIntervalEnd && !fShutdown; nTimeTx++)
658 // Complete first hashing iteration
660 SHA256_Update(&ctx, (unsigned char*)&nTimeTx, 4);
661 SHA256_Final((unsigned char*)&hash1, &ctx);
666 // Finally, calculate kernel hash
667 SHA256((unsigned char*)&hash1, sizeof(hashProofOfStake), (unsigned char*)&hashProofOfStake);
669 // Skip if hash doesn't satisfy the maximum target
670 if (hashProofOfStake[7] > nMaxTarget32)
673 CBigNum bnCoinDayWeight = bnValueIn * GetWeight((int64_t)nInputTxTime, (int64_t)nTimeTx) / COIN / nOneDay;
674 CBigNum bnTargetProofOfStake = bnCoinDayWeight * bnTargetPerCoinDay;
676 if (bnTargetProofOfStake >= CBigNum(*pnHashProofOfStake))
677 solutions.push_back(std::pair<uint256,uint32_t>(*pnHashProofOfStake, nTimeTx));
681 vector<std::pair<uint256,uint32_t> >& GetSolutions()
687 SHA256_CTX workerCtx;
688 std::vector<std::pair<uint256,uint32_t> > solutions;
691 uint32_t nInputTxTime;
693 uint32_t nIntervalBegin;
694 uint32_t nIntervalEnd;
698 // Scan given kernel for solution
699 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)
701 // TODO: custom threads amount
703 uint32_t nThreads = boost::thread::hardware_concurrency();
704 uint32_t nPart = (SearchInterval.second - SearchInterval.first) / nThreads;
707 ScanMidstateWorker *workers = new ScanMidstateWorker[nThreads];
709 boost::thread_group group;
710 for(size_t i = 0; i < nThreads; i++)
712 uint32_t nBegin = SearchInterval.first + nPart * i;
713 uint32_t nEnd = SearchInterval.first + nPart * (i + 1);
714 workers[i] = ScanMidstateWorker(kernel, nBits, nInputTxTime, nValueIn, nBegin, nEnd);
715 boost::function<void()> workerFnc = boost::bind(&ScanMidstateWorker::Do, &workers[i]);
716 group.create_thread(workerFnc);
722 for(size_t i = 0; i < nThreads; i++)
724 std::vector<std::pair<uint256, uint32_t> > ws = workers[i].GetSolutions();
725 solutions.insert(solutions.end(), ws.begin(), ws.end());
730 if (solutions.size() == 0)
739 // Scan given midstate for solution
740 bool ScanContextBackward(SHA256_CTX &ctx, uint32_t nBits, uint32_t nInputTxTime, int64_t nValueIn, std::pair<uint32_t, uint32_t> &SearchInterval, std::pair<uint256, uint32_t> &solution)
742 CBigNum bnTargetPerCoinDay;
743 bnTargetPerCoinDay.SetCompact(nBits);
745 // Get maximum possible target to filter out the majority of obviously insufficient hashes
746 CBigNum bnMaxTargetPerCoinDay = bnTargetPerCoinDay * CBigNum(nValueIn) * nStakeMaxAge / COIN / nOneDay;
747 uint256 maxTarget = bnMaxTargetPerCoinDay.getuint256();
749 SHA256_CTX ctxCopy = ctx;
751 // Search backward in time from the given timestamp
752 // Stopping search in case of shutting down
753 for (uint32_t nTimeTx=SearchInterval.first; nTimeTx>SearchInterval.second && !fShutdown; nTimeTx--)
755 // Complete first hashing iteration
757 SHA256_Update(&ctxCopy, (unsigned char*)&nTimeTx, 4);
758 SHA256_Final((unsigned char*)&hash1, &ctxCopy);
763 // Finally, calculate kernel hash
764 uint256 hashProofOfStake;
765 SHA256((unsigned char*)&hash1, sizeof(hashProofOfStake), (unsigned char*)&hashProofOfStake);
767 // Skip if hash doesn't satisfy the maximum target
768 if (hashProofOfStake > maxTarget)
771 CBigNum bnCoinDayWeight = CBigNum(nValueIn) * GetWeight((int64_t)nInputTxTime, (int64_t)nTimeTx) / COIN / nOneDay;
772 CBigNum bnTargetProofOfStake = bnCoinDayWeight * bnTargetPerCoinDay;
774 if (bnTargetProofOfStake >= CBigNum(hashProofOfStake))
776 solution.first = hashProofOfStake;
777 solution.second = nTimeTx;
786 // Check kernel hash target and coinstake signature
787 bool CheckProofOfStake(const CTransaction& tx, unsigned int nBits, uint256& hashProofOfStake, uint256& targetProofOfStake)
789 if (!tx.IsCoinStake())
790 return error("CheckProofOfStake() : called on non-coinstake %s", tx.GetHash().ToString().c_str());
792 // Kernel (input 0) must match the stake hash target per coin age (nBits)
793 const CTxIn& txin = tx.vin[0];
795 // First try finding the previous transaction in database
799 if (!txPrev.ReadFromDisk(txdb, txin.prevout, txindex))
800 return tx.DoS(1, error("CheckProofOfStake() : INFO: read txPrev failed")); // previous transaction not in main chain, may occur during initial download
807 if (!VerifySignature(txPrev, tx, 0, MANDATORY_SCRIPT_VERIFY_FLAGS, 0))
808 return tx.DoS(100, error("CheckProofOfStake() : VerifySignature failed on coinstake %s", tx.GetHash().ToString().c_str()));
812 if (!block.ReadFromDisk(txindex.pos.nFile, txindex.pos.nBlockPos, false))
813 return fDebug? error("CheckProofOfStake() : read block failed") : false; // unable to read block of previous transaction
815 if (!CheckStakeKernelHash(nBits, block, txindex.pos.nTxPos - txindex.pos.nBlockPos, txPrev, txin.prevout, tx.nTime, hashProofOfStake, targetProofOfStake, fDebug))
816 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
821 // Get stake modifier checksum
822 uint32_t GetStakeModifierChecksum(const CBlockIndex* pindex)
824 assert (pindex->pprev || pindex->GetBlockHash() == (!fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet));
825 // Hash previous checksum with flags, hashProofOfStake and nStakeModifier
826 CDataStream ss(SER_GETHASH, 0);
828 ss << pindex->pprev->nStakeModifierChecksum;
829 ss << pindex->nFlags << pindex->hashProofOfStake << pindex->nStakeModifier;
830 uint256 hashChecksum = Hash(ss.begin(), ss.end());
831 hashChecksum >>= (256 - 32);
832 return static_cast<uint32_t>(hashChecksum.Get64());
835 // Check stake modifier hard checkpoints
836 bool CheckStakeModifierCheckpoints(int nHeight, uint32_t nStakeModifierChecksum)
838 MapModifierCheckpoints& checkpoints = (fTestNet ? mapStakeModifierCheckpointsTestNet : mapStakeModifierCheckpoints);
840 if (checkpoints.count(nHeight))
841 return nStakeModifierChecksum == checkpoints[nHeight];