return (nTimeBlock >= (fTestNet? nModifierTestSwitchTime : nModifierSwitchTime));
}
-// Get time weight
-int64_t GetWeight(int64_t nIntervalBeginning, int64_t nIntervalEnd)
-{
- // Kernel hash weight starts from 0 at the 30-day min age
- // this change increases active coins participating the hash and helps
- // to secure the network when proof-of-stake difficulty is low
- //
- // Maximum TimeWeight is 90 days.
-
- return min(nIntervalEnd - nIntervalBeginning - nStakeMinAge, (int64_t)nStakeMaxAge);
-}
-
// Get the last stake modifier and its generation time from a given block
static bool GetLastStakeModifier(const CBlockIndex* pindex, uint64_t& nStakeModifier, int64_t& nModifierTime)
{
DateTimeStrFormat(nStakeModifierTime).c_str(),
mapBlockIndex[hashBlockFrom]->nHeight,
DateTimeStrFormat(blockFrom.GetBlockTime()).c_str());
- printf("CheckStakeKernelHash() : check modifier=0x%016" PRIx64 " nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashProof=%s\n",
+ printf("CheckStakeKernelHash() : check modifier=0x%016" PRIx64 " nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashTarget=%s hashProof=%s\n",
nStakeModifier,
nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx,
- hashProofOfStake.ToString().c_str());
+ targetProofOfStake.ToString().c_str(), hashProofOfStake.ToString().c_str());
}
// Now check if proof-of-stake hash meets target protocol
DateTimeStrFormat(nStakeModifierTime).c_str(),
mapBlockIndex[hashBlockFrom]->nHeight,
DateTimeStrFormat(blockFrom.GetBlockTime()).c_str());
- printf("CheckStakeKernelHash() : pass modifier=0x%016" PRIx64 " nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashProof=%s\n",
+ printf("CheckStakeKernelHash() : pass modifier=0x%016" PRIx64 " nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashTarget=%s hashProof=%s\n",
nStakeModifier,
nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx,
- hashProofOfStake.ToString().c_str());
+ targetProofOfStake.ToString().c_str(), hashProofOfStake.ToString().c_str());
}
return true;
}
-// Scan given coins set for kernel solution
-bool ScanForStakeKernelHash(MetaMap &mapMeta, uint32_t nBits, uint32_t nTime, uint32_t nSearchInterval, CoinsSet::value_type &kernelcoin, uint32_t &nTimeTx, uint32_t &nBlockTime, uint64_t &nKernelsTried, uint64_t &nCoinDaysTried)
+// Precompute hashing state for static part of kernel
+void GetKernelMidstate(uint64_t nStakeModifier, uint32_t nBlockTime, uint32_t nTxOffset, uint32_t nInputTxTime, uint32_t nOut, SHA256_CTX &ctx)
{
- uint256 hashProofOfStake = 0;
+ // Build static part of kernel
+ CDataStream ssKernel(SER_GETHASH, 0);
+ ssKernel << nStakeModifier;
+ ssKernel << nBlockTime << nTxOffset << nInputTxTime << nOut;
+ CDataStream::const_iterator it = ssKernel.begin();
+
+ // Init sha256 context and update it
+ // with first 24 bytes of kernel
+ SHA256_Init(&ctx);
+ SHA256_Update(&ctx, (unsigned char*)&it[0], 8 + 16);
+}
- // (txid, vout.n) => ((txindex, (tx, vout.n)), (block, modifier))
- for(MetaMap::const_iterator meta_item = mapMeta.begin(); meta_item != mapMeta.end(); meta_item++)
- {
- if (!fCoinsDataActual)
- break;
+// Scan given midstate for solution
+bool ScanMidstateForward(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)
+{
+ CBigNum bnTargetPerCoinDay;
+ bnTargetPerCoinDay.SetCompact(nBits);
- CTxIndex txindex = (*meta_item).second.first.first;
- CBlock block = (*meta_item).second.second.first;
- uint64_t nStakeModifier = (*meta_item).second.second.second;
+ // Get maximum possible target to filter out the majority of obviously insufficient hashes
+ CBigNum bnMaxTargetPerCoinDay = bnTargetPerCoinDay * CBigNum(nValueIn) * nStakeMaxAge / COIN / (24 * 60 * 60);
+ uint256 maxTarget = bnMaxTargetPerCoinDay.getuint256();
- // Get coin
- CoinsSet::value_type pcoin = meta_item->second.first.second;
+ SHA256_CTX ctxCopy = ctx;
- static unsigned int nMaxStakeSearchInterval = 60;
+ // Search forward in time from the given timestamp
+ // Stopping search in case of shutting down
+ for (uint32_t nTimeTx=SearchInterval.first; nTimeTx<SearchInterval.second && !fShutdown; nTimeTx++)
+ {
+ // Complete first hashing iteration
+ uint256 hash1;
+ SHA256_Update(&ctxCopy, (unsigned char*)&nTimeTx, 4);
+ SHA256_Final((unsigned char*)&hash1, &ctxCopy);
- // only count coins meeting min age requirement
- if (nStakeMinAge + block.nTime > nTime - nMaxStakeSearchInterval)
- continue;
+ // Restore context
+ ctxCopy = ctx;
- // Transaction offset inside block
- uint32_t nTxOffset = txindex.pos.nTxPos - txindex.pos.nBlockPos;
+ // Finally, calculate kernel hash
+ uint256 hashProofOfStake;
+ SHA256((unsigned char*)&hash1, sizeof(hashProofOfStake), (unsigned char*)&hashProofOfStake);
- // Current timestamp scanning interval
- unsigned int nCurrentSearchInterval = min(nSearchInterval, nMaxStakeSearchInterval);
+ // Skip if hash doesn't satisfy the maximum target
+ if (hashProofOfStake > maxTarget)
+ continue;
- nBlockTime = block.nTime;
- CBigNum bnTargetPerCoinDay;
- bnTargetPerCoinDay.SetCompact(nBits);
- int64_t nValueIn = pcoin.first->vout[pcoin.second].nValue;
+ CBigNum bnCoinDayWeight = CBigNum(nValueIn) * GetWeight((int64_t)nInputTxTime, (int64_t)nTimeTx) / COIN / (24 * 60 * 60);
+ CBigNum bnTargetProofOfStake = bnCoinDayWeight * bnTargetPerCoinDay;
- // Search backward in time from the given timestamp
- // Search nSearchInterval seconds back up to nMaxStakeSearchInterval
- // Stopping search in case of shutting down or cache invalidation
- for (unsigned int n=0; n<nCurrentSearchInterval && fCoinsDataActual && !fShutdown; n++)
+ if (bnTargetProofOfStake >= CBigNum(hashProofOfStake))
{
- nTimeTx = nTime - n;
- CBigNum bnCoinDayWeight = CBigNum(nValueIn) * GetWeight((int64_t)pcoin.first->nTime, (int64_t)nTimeTx) / COIN / (24 * 60 * 60);
- CBigNum bnTargetProofOfStake = bnCoinDayWeight * bnTargetPerCoinDay;
-
- // Build kernel
- CDataStream ss(SER_GETHASH, 0);
- ss << nStakeModifier;
- ss << nBlockTime << nTxOffset << pcoin.first->nTime << pcoin.second << nTimeTx;
-
- // Calculate kernel hash
- hashProofOfStake = Hash(ss.begin(), ss.end());
-
- // Update statistics
- nKernelsTried += 1;
- nCoinDaysTried += bnCoinDayWeight.getuint64();
-
- if (bnTargetProofOfStake >= CBigNum(hashProofOfStake))
- {
- if (fDebug)
- printf("nStakeModifier=0x%016" PRIx64 ", nBlockTime=%u nTxOffset=%u nTxPrevTime=%u nVout=%u nTimeTx=%u hashProofOfStake=%s Success=true\n",
- nStakeModifier, nBlockTime, nTxOffset, pcoin.first->nTime, pcoin.second, nTimeTx, hashProofOfStake.GetHex().c_str());
-
- kernelcoin = pcoin;
- return true;
- }
+ solution.first = hashProofOfStake;
+ solution.second = nTimeTx;
- if (fDebug)
- printf("nStakeModifier=0x%016" PRIx64 ", nBlockTime=%u nTxOffset=%u nTxPrevTime=%u nTxNumber=%u nTimeTx=%u hashProofOfStake=%s Success=false\n",
- nStakeModifier, nBlockTime, nTxOffset, pcoin.first->nTime, pcoin.second, nTimeTx, hashProofOfStake.GetHex().c_str());
+ return true;
}
}
return false;
}
-// Scan given input for kernel solution
-bool ScanInputForStakeKernelHash(CTransaction &tx, uint32_t nOut, uint32_t nBits, uint32_t nSearchInterval, std::pair<uint256, uint32_t> &solution)
+// Scan given midstate for solution
+bool ScanMidstateBackward(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)
{
- CTxDB txdb("r");
-
- CBlock block;
- CTxIndex txindex;
-
- // Load transaction index item
- if (!txdb.ReadTxIndex(tx.GetHash(), txindex))
- return false;
-
- // Read block header
- if (!block.ReadFromDisk(txindex.pos.nFile, txindex.pos.nBlockPos, false))
- return false;
-
- uint64_t nStakeModifier = 0;
- if (!GetKernelStakeModifier(block.GetHash(), nStakeModifier))
- return false;
-
- uint32_t nTime = GetTime();
- // Only count coins meeting min age requirement
- if (nStakeMinAge + block.nTime > nTime)
- nTime += (nStakeMinAge + block.nTime - nTime);
-
- // Transaction offset inside block
- uint32_t nTxOffset = txindex.pos.nTxPos - txindex.pos.nBlockPos;
- int64_t nValueIn = tx.vout[nOut].nValue;
-
CBigNum bnTargetPerCoinDay;
bnTargetPerCoinDay.SetCompact(nBits);
CBigNum bnMaxTargetPerCoinDay = bnTargetPerCoinDay * CBigNum(nValueIn) * nStakeMaxAge / COIN / (24 * 60 * 60);
uint256 maxTarget = bnMaxTargetPerCoinDay.getuint256();
- // Search forward in time from the given timestamp
+ SHA256_CTX ctxCopy = ctx;
+
+ // Search backward in time from the given timestamp
// Stopping search in case of shutting down
- for (unsigned int n=0; n<nSearchInterval && !fShutdown; n++)
+ for (uint32_t nTimeTx=SearchInterval.first; nTimeTx>SearchInterval.second && !fShutdown; nTimeTx--)
{
- uint32_t nTimeTx = nTime + n;
+ // Complete first hashing iteration
+ uint256 hash1;
+ SHA256_Update(&ctxCopy, (unsigned char*)&nTimeTx, 4);
+ SHA256_Final((unsigned char*)&hash1, &ctxCopy);
- // Build kernel
- CDataStream ss(SER_GETHASH, 0);
- ss << nStakeModifier;
- ss << block.nTime << nTxOffset << tx.nTime << nOut << nTimeTx;
+ // Restore context
+ ctxCopy = ctx;
- // Calculate kernel hash
- uint256 hashProofOfStake = Hash(ss.begin(), ss.end());
+ // Finally, calculate kernel hash
+ uint256 hashProofOfStake;
+ SHA256((unsigned char*)&hash1, sizeof(hashProofOfStake), (unsigned char*)&hashProofOfStake);
// Skip if hash doesn't satisfy the maximum target
if (hashProofOfStake > maxTarget)
continue;
- CBigNum bnCoinDayWeight = CBigNum(nValueIn) * GetWeight((int64_t)tx.nTime, (int64_t)nTimeTx) / COIN / (24 * 60 * 60);
+ CBigNum bnCoinDayWeight = CBigNum(nValueIn) * GetWeight((int64_t)nInputTxTime, (int64_t)nTimeTx) / COIN / (24 * 60 * 60);
CBigNum bnTargetProofOfStake = bnCoinDayWeight * bnTargetPerCoinDay;
if (bnTargetProofOfStake >= CBigNum(hashProofOfStake))
ss << pindex->nFlags << pindex->hashProofOfStake << pindex->nStakeModifier;
uint256 hashChecksum = Hash(ss.begin(), ss.end());
hashChecksum >>= (256 - 32);
- return hashChecksum.Get64();
+ return static_cast<uint32_t>(hashChecksum.Get64());
}
// Check stake modifier hard checkpoints
git://git.novaco.in / novacoin.git / blobdiff