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kernel.cpp
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kernel.cpp
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// Copyright (c) 2012-2013 The PPCoin developers
// Copyright (c) 2013-2015 The Novacoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <boost/assign/list_of.hpp>
#include "kernel.h"
#include "txdb.h"
extern unsigned int nStakeMaxAge;
extern unsigned int nStakeTargetSpacing;
using namespace std;
// Protocol switch time for fixed kernel modifier interval
unsigned int nModifierSwitchTime = 1413763200; // Mon, 20 Oct 2014 00:00:00 GMT
unsigned int nModifierTestSwitchTime = 1397520000; // Tue, 15 Apr 2014 00:00:00 GMT
// Note: user must upgrade before the protocol switch deadline, otherwise it's required to
// re-download the blockchain. The timestamp of upgrade is recorded in the blockchain
// database.
unsigned int nModifierUpgradeTime = 0;
typedef std::map<int, unsigned int> MapModifierCheckpoints;
// Hard checkpoints of stake modifiers to ensure they are deterministic
static std::map<int, unsigned int> mapStakeModifierCheckpoints =
boost::assign::map_list_of
( 0, 0x0e00670bu )
( 12661, 0x5d84115du )
(143990, 0x9c592c78u )
(149000, 0x48f2bdc4u )
(160000, 0x789df0f0u )
(200000, 0x01ec1503u )
;
// Hard checkpoints of stake modifiers to ensure they are deterministic (testNet)
static std::map<int, unsigned int> mapStakeModifierCheckpointsTestNet =
boost::assign::map_list_of
( 0, 0x0e00670bu )
;
// Pregenerated entropy bits table (from genesis to #9689)
//
// Bits are packed into array of 256 bit integers:
//
// * array index calculated as nHeight / 256
// * position of bit is calculated as nHeight & 0xFF.
//
const uint256 entropyStore[] = {
uint256("0x4555b4dcc1d690ddd9b810c90c66e82b18bf4f43cc887246c418383ec120a5ab"),
uint256("0xaa6d1198412fa77608addf6549c9198a22155e8afd7a9ded6179f6b7cfc66b0c"),
uint256("0x9442fabfa4116fb14a9769c2eea003845a1f5c3a0260f36b497d68f3a3cd4078"),
uint256("0x0e769042a9a98e42388195d699574b822d06515f7053ad884c53d7ee059f05b1"),
uint256("0x7005aac20baf70251aebfe3f1b95987d83ef1e3e6963de8fed601d4dd07bf7cf"),
uint256("0x58952c5c3de188f2e33c38d3f53d7bf44f9bc545a4289d266696273fa821be66"),
uint256("0x50b6c2ed780c08aaec3f7665b1b6004206243e3866456fc910b83b52d07eeb63"),
uint256("0x563841eefca85ba3384986c58100408ae3f1ba2ac727e1ac910ce154a06c702f"),
uint256("0x79275b03938b3e27a9b01a7f7953c6c487c58355f5d4169accfbb800213ffd13"),
uint256("0xd783f2538b3ed18f135af90adc687c5646d93aeaeaabc6667be94f7aa0a2d366"),
uint256("0xb441d0c175c40c8e88b09d88ea008af79cbed2d28219427d2e72fda682974db8"),
uint256("0x3204c43bd41f2e19628af3b0c9aca3db15bca4c8705d51056e7b17a319c04715"),
uint256("0x7e80e6ab7857d8f2f261a0a49c783bd800b365b8c9b85cc0e13f73904b0dcaa9"),
uint256("0xefaaee60ed82d2ad145c0e347941fdb131eb8fd289a45eef07121a93f283c5f1"),
uint256("0x3efc86e4334da332c1fd4c12513c40cff689f3efdc7f9913230822adacdda4f9"),
uint256("0xf0d6b8f38599a017fa35d1fbbf9ef51eca5ebc5b286aadba40c4c3e1d9bace0c"),
uint256("0x286a67f27323486036a0a92d35382fc8963c0c00bad331723318b4b9fdb2b56e"),
uint256("0xecbfaaa6567c54f08c4d5bd0118a2d7b58740f42cbfc73aa1536c1f5f76de87c"),
uint256("0xf9a4de1c5c46520de5aaf10d3796cf0e27ddce98b3398357f5726a949664e308"),
uint256("0xd75e6c4dc4be08401e3478d2467d9ab96a62af4f255c04a82c41af0de0a487bb"),
uint256("0x1a82c3bc6ad6047294c16571b5e2b7316c97bf8813e7da15798b9820d67e39f2"),
uint256("0xb49be0080de564e01829ded7e7971979565a741c5975dc9978dcc020192d396c"),
uint256("0x0d8eed113be67663b5a15a0625a9b49792b5ea59c005c4f405914877acab7000"),
uint256("0x8f9d46e2bc05a218ffa942965b747056197d393b097085523640cd59e07fe7c7"),
uint256("0x7a63ab40bc7f40ac2ebe9ede438d97b45fa6ed6f8419016da8d5f7a670111dda"),
uint256("0x63fbcc080448c43d6cf915c958314feff7a95a52ba43a68c05fc281d3a522d25"),
uint256("0xf834cf824c326d3ea861ea1e85dc3289265e37045981e28208e7344a7f8081d7"),
uint256("0xb4edc22ec98cc49b2f5af5bae3f52f5e6058280f74f2c432c2dd89ae49acceb8"),
uint256("0x0fe596037dcf81bf5c64f39755261c404ed088af5c8c31dd7549b6657ee92365"),
uint256("0xbbad51a0aeba254b01d18c328de9e932b9b859b61e622c325d64e2211b5e413d"),
uint256("0xabf0194cc787be938bc51c7fdf1cae4ec79e65ebab8fa8b8f40541c44ef384b0"),
uint256("0x83bc12d6fdbd3e854cb91c4ca7dfba3c38e8714121af88c8a8abdb33e5002438"),
uint256("0x71a2513026cabaedcbe55aeb6dc8049e5b763a3f54f10c33dd333624f764b38c"),
uint256("0xee6725632ff5c025dff6a18cd059875dcae20f399b03bccba13d9d5fcf6d9d9a"),
uint256("0xa168a2741d1e7e50cc74b79f695c25ffd3576e6bd61353c2a20e569fd63b2dac"),
uint256("0x6e462d2a87bfde9398b6747f94a8ed6a01e4d96c5b4372df5c910c106c48bd13"),
uint256("0x8eeb696181957c4b22434028990f49cb30006827c73860e77e2eecf5c38be99d"),
uint256("0x3188aaa65877b166f05cdc48f55b1f77a7d6fb221c395596d990ae5647e9ba96")
};
// Whether the given block is subject to new modifier protocol
bool IsFixedModifierInterval(unsigned int nTimeBlock)
{
return (nTimeBlock >= (fTestNet? nModifierTestSwitchTime : nModifierSwitchTime));
}
// 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)
{
if (!pindex)
return error("GetLastStakeModifier: null pindex");
while (pindex && pindex->pprev && !pindex->GeneratedStakeModifier())
pindex = pindex->pprev;
if (!pindex->GeneratedStakeModifier())
return error("GetLastStakeModifier: no generation at genesis block");
nStakeModifier = pindex->nStakeModifier;
nModifierTime = pindex->GetBlockTime();
return true;
}
// Get selection interval section (in seconds)
static int64_t GetStakeModifierSelectionIntervalSection(int nSection)
{
assert (nSection >= 0 && nSection < 64);
return (nModifierInterval * 63 / (63 + ((63 - nSection) * (MODIFIER_INTERVAL_RATIO - 1))));
}
// Get stake modifier selection interval (in seconds)
static int64_t GetStakeModifierSelectionInterval()
{
int64_t nSelectionInterval = 0;
for (int nSection=0; nSection<64; nSection++)
nSelectionInterval += GetStakeModifierSelectionIntervalSection(nSection);
return nSelectionInterval;
}
// select a block from the candidate blocks in vSortedByTimestamp, excluding
// already selected blocks in vSelectedBlocks, and with timestamp up to
// nSelectionIntervalStop.
static bool SelectBlockFromCandidates(vector<pair<int64_t, uint256> >& vSortedByTimestamp, map<uint256, const CBlockIndex*>& mapSelectedBlocks,
int64_t nSelectionIntervalStop, uint64_t nStakeModifierPrev, const CBlockIndex** pindexSelected)
{
bool fSelected = false;
uint256 hashBest = 0;
*pindexSelected = (const CBlockIndex*) 0;
BOOST_FOREACH(const PAIRTYPE(int64_t, uint256)& item, vSortedByTimestamp)
{
if (!mapBlockIndex.count(item.second))
return error("SelectBlockFromCandidates: failed to find block index for candidate block %s", item.second.ToString().c_str());
const CBlockIndex* pindex = mapBlockIndex[item.second];
if (fSelected && pindex->GetBlockTime() > nSelectionIntervalStop)
break;
if (mapSelectedBlocks.count(pindex->GetBlockHash()) > 0)
continue;
// compute the selection hash by hashing its proof-hash and the
// previous proof-of-stake modifier
uint256 hashProof = pindex->IsProofOfStake()? pindex->hashProofOfStake : pindex->GetBlockHash();
CDataStream ss(SER_GETHASH, 0);
ss << hashProof << nStakeModifierPrev;
uint256 hashSelection = Hash(ss.begin(), ss.end());
// the selection hash is divided by 2**32 so that proof-of-stake block
// is always favored over proof-of-work block. this is to preserve
// the energy efficiency property
if (pindex->IsProofOfStake())
hashSelection >>= 32;
if (fSelected && hashSelection < hashBest)
{
hashBest = hashSelection;
*pindexSelected = (const CBlockIndex*) pindex;
}
else if (!fSelected)
{
fSelected = true;
hashBest = hashSelection;
*pindexSelected = (const CBlockIndex*) pindex;
}
}
if (fDebug && GetBoolArg("-printstakemodifier"))
printf("SelectBlockFromCandidates: selection hash=%s\n", hashBest.ToString().c_str());
return fSelected;
}
// Stake Modifier (hash modifier of proof-of-stake):
// The purpose of stake modifier is to prevent a txout (coin) owner from
// computing future proof-of-stake generated by this txout at the time
// of transaction confirmation. To meet kernel protocol, the txout
// must hash with a future stake modifier to generate the proof.
// Stake modifier consists of bits each of which is contributed from a
// selected block of a given block group in the past.
// The selection of a block is based on a hash of the block's proof-hash and
// the previous stake modifier.
// Stake modifier is recomputed at a fixed time interval instead of every
// block. This is to make it difficult for an attacker to gain control of
// additional bits in the stake modifier, even after generating a chain of
// blocks.
bool ComputeNextStakeModifier(const CBlockIndex* pindexCurrent, uint64_t& nStakeModifier, bool& fGeneratedStakeModifier)
{
nStakeModifier = 0;
fGeneratedStakeModifier = false;
const CBlockIndex* pindexPrev = pindexCurrent->pprev;
if (!pindexPrev)
{
fGeneratedStakeModifier = true;
return true; // genesis block's modifier is 0
}
// First find current stake modifier and its generation block time
// if it's not old enough, return the same stake modifier
int64_t nModifierTime = 0;
if (!GetLastStakeModifier(pindexPrev, nStakeModifier, nModifierTime))
return error("ComputeNextStakeModifier: unable to get last modifier");
if (fDebug)
{
printf("ComputeNextStakeModifier: prev modifier=0x%016" PRIx64 " time=%s epoch=%u\n", nStakeModifier, DateTimeStrFormat(nModifierTime).c_str(), (unsigned int)nModifierTime);
}
if (nModifierTime / nModifierInterval >= pindexPrev->GetBlockTime() / nModifierInterval)
{
if (fDebug)
{
printf("ComputeNextStakeModifier: no new interval keep current modifier: pindexPrev nHeight=%d nTime=%u\n", pindexPrev->nHeight, (unsigned int)pindexPrev->GetBlockTime());
}
return true;
}
if (nModifierTime / nModifierInterval >= pindexCurrent->GetBlockTime() / nModifierInterval)
{
// fixed interval protocol requires current block timestamp also be in a different modifier interval
if (IsFixedModifierInterval(pindexCurrent->nTime))
{
if (fDebug)
{
printf("ComputeNextStakeModifier: no new interval keep current modifier: pindexCurrent nHeight=%d nTime=%u\n", pindexCurrent->nHeight, (unsigned int)pindexCurrent->GetBlockTime());
}
return true;
}
else
{
if (fDebug)
{
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());
}
}
}
// Sort candidate blocks by timestamp
vector<pair<int64_t, uint256> > vSortedByTimestamp;
vSortedByTimestamp.reserve(64 * nModifierInterval / nStakeTargetSpacing);
int64_t nSelectionInterval = GetStakeModifierSelectionInterval();
int64_t nSelectionIntervalStart = (pindexPrev->GetBlockTime() / nModifierInterval) * nModifierInterval - nSelectionInterval;
const CBlockIndex* pindex = pindexPrev;
while (pindex && pindex->GetBlockTime() >= nSelectionIntervalStart)
{
vSortedByTimestamp.push_back(make_pair(pindex->GetBlockTime(), pindex->GetBlockHash()));
pindex = pindex->pprev;
}
int nHeightFirstCandidate = pindex ? (pindex->nHeight + 1) : 0;
reverse(vSortedByTimestamp.begin(), vSortedByTimestamp.end());
sort(vSortedByTimestamp.begin(), vSortedByTimestamp.end());
// Select 64 blocks from candidate blocks to generate stake modifier
uint64_t nStakeModifierNew = 0;
int64_t nSelectionIntervalStop = nSelectionIntervalStart;
map<uint256, const CBlockIndex*> mapSelectedBlocks;
for (int nRound=0; nRound<min(64, (int)vSortedByTimestamp.size()); nRound++)
{
// add an interval section to the current selection round
nSelectionIntervalStop += GetStakeModifierSelectionIntervalSection(nRound);
// select a block from the candidates of current round
if (!SelectBlockFromCandidates(vSortedByTimestamp, mapSelectedBlocks, nSelectionIntervalStop, nStakeModifier, &pindex))
return error("ComputeNextStakeModifier: unable to select block at round %d", nRound);
// write the entropy bit of the selected block
nStakeModifierNew |= (((uint64_t)pindex->GetStakeEntropyBit()) << nRound);
// add the selected block from candidates to selected list
mapSelectedBlocks.insert(make_pair(pindex->GetBlockHash(), pindex));
if (fDebug && GetBoolArg("-printstakemodifier"))
printf("ComputeNextStakeModifier: selected round %d stop=%s height=%d bit=%d\n", nRound, DateTimeStrFormat(nSelectionIntervalStop).c_str(), pindex->nHeight, pindex->GetStakeEntropyBit());
}
// Print selection map for visualization of the selected blocks
if (fDebug && GetBoolArg("-printstakemodifier"))
{
string strSelectionMap = "";
// '-' indicates proof-of-work blocks not selected
strSelectionMap.insert(0, pindexPrev->nHeight - nHeightFirstCandidate + 1, '-');
pindex = pindexPrev;
while (pindex && pindex->nHeight >= nHeightFirstCandidate)
{
// '=' indicates proof-of-stake blocks not selected
if (pindex->IsProofOfStake())
strSelectionMap.replace(pindex->nHeight - nHeightFirstCandidate, 1, "=");
pindex = pindex->pprev;
}
BOOST_FOREACH(const PAIRTYPE(uint256, const CBlockIndex*)& item, mapSelectedBlocks)
{
// 'S' indicates selected proof-of-stake blocks
// 'W' indicates selected proof-of-work blocks
strSelectionMap.replace(item.second->nHeight - nHeightFirstCandidate, 1, item.second->IsProofOfStake()? "S" : "W");
}
printf("ComputeNextStakeModifier: selection height [%d, %d] map %s\n", nHeightFirstCandidate, pindexPrev->nHeight, strSelectionMap.c_str());
}
if (fDebug)
{
printf("ComputeNextStakeModifier: new modifier=0x%016" PRIx64 " time=%s\n", nStakeModifierNew, DateTimeStrFormat(pindexPrev->GetBlockTime()).c_str());
}
nStakeModifier = nStakeModifierNew;
fGeneratedStakeModifier = true;
return true;
}
// The stake modifier used to hash for a stake kernel is chosen as the stake
// modifier about a selection interval later than the coin generating the kernel
static bool GetKernelStakeModifier(uint256 hashBlockFrom, uint64_t& nStakeModifier, int& nStakeModifierHeight, int64_t& nStakeModifierTime, bool fPrintProofOfStake)
{
nStakeModifier = 0;
if (!mapBlockIndex.count(hashBlockFrom))
return error("GetKernelStakeModifier() : block not indexed");
const CBlockIndex* pindexFrom = mapBlockIndex[hashBlockFrom];
nStakeModifierHeight = pindexFrom->nHeight;
nStakeModifierTime = pindexFrom->GetBlockTime();
int64_t nStakeModifierSelectionInterval = GetStakeModifierSelectionInterval();
const CBlockIndex* pindex = pindexFrom;
// loop to find the stake modifier later by a selection interval
while (nStakeModifierTime < pindexFrom->GetBlockTime() + nStakeModifierSelectionInterval)
{
if (!pindex->pnext)
{ // reached best block; may happen if node is behind on block chain
if (fPrintProofOfStake || (pindex->GetBlockTime() + nStakeMinAge - nStakeModifierSelectionInterval > GetAdjustedTime()))
return error("GetKernelStakeModifier() : reached best block %s at height %d from block %s",
pindex->GetBlockHash().ToString().c_str(), pindex->nHeight, hashBlockFrom.ToString().c_str());
else
return false;
}
pindex = pindex->pnext;
if (pindex->GeneratedStakeModifier())
{
nStakeModifierHeight = pindex->nHeight;
nStakeModifierTime = pindex->GetBlockTime();
}
}
nStakeModifier = pindex->nStakeModifier;
return true;
}
bool GetKernelStakeModifier(uint256 hashBlockFrom, uint64_t& nStakeModifier)
{
int nStakeModifierHeight;
int64_t nStakeModifierTime;
return GetKernelStakeModifier(hashBlockFrom, nStakeModifier, nStakeModifierHeight, nStakeModifierTime, false);
}
// ppcoin kernel protocol
// coinstake must meet hash target according to the protocol:
// kernel (input 0) must meet the formula
// hash(nStakeModifier + txPrev.block.nTime + txPrev.offset + txPrev.nTime + txPrev.vout.n + nTime) < bnTarget * nCoinDayWeight
// this ensures that the chance of getting a coinstake is proportional to the
// amount of coin age one owns.
// The reason this hash is chosen is the following:
// nStakeModifier: scrambles computation to make it very difficult to precompute
// future proof-of-stake at the time of the coin's confirmation
// txPrev.block.nTime: prevent nodes from guessing a good timestamp to
// generate transaction for future advantage
// txPrev.offset: offset of txPrev inside block, to reduce the chance of
// nodes generating coinstake at the same time
// txPrev.nTime: reduce the chance of nodes generating coinstake at the same
// time
// txPrev.vout.n: output number of txPrev, to reduce the chance of nodes
// generating coinstake at the same time
// block/tx hash should not be used here as they can be generated in vast
// quantities so as to generate blocks faster, degrading the system back into
// a proof-of-work situation.
//
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)
{
if (nTimeTx < txPrev.nTime) // Transaction timestamp violation
return error("CheckStakeKernelHash() : nTime violation");
uint32_t nTimeBlockFrom = blockFrom.GetBlockTime();
if (nTimeBlockFrom + nStakeMinAge > nTimeTx) // Min age requirement
return error("CheckStakeKernelHash() : min age violation");
CBigNum bnTargetPerCoinDay;
bnTargetPerCoinDay.SetCompact(nBits);
int64_t nValueIn = txPrev.vout[prevout.n].nValue;
uint256 hashBlockFrom = blockFrom.GetHash();
CBigNum bnCoinDayWeight = CBigNum(nValueIn) * GetWeight((int64_t)txPrev.nTime, (int64_t)nTimeTx) / COIN / nOneDay;
targetProofOfStake = (bnCoinDayWeight * bnTargetPerCoinDay).getuint256();
// Calculate hash
CDataStream ss(SER_GETHASH, 0);
uint64_t nStakeModifier = 0;
int nStakeModifierHeight = 0;
int64_t nStakeModifierTime = 0;
if (!GetKernelStakeModifier(hashBlockFrom, nStakeModifier, nStakeModifierHeight, nStakeModifierTime, fPrintProofOfStake))
return false;
ss << nStakeModifier;
ss << nTimeBlockFrom << nTxPrevOffset << txPrev.nTime << prevout.n << nTimeTx;
hashProofOfStake = Hash(ss.begin(), ss.end());
if (fPrintProofOfStake)
{
printf("CheckStakeKernelHash() : using modifier 0x%016" PRIx64 " at height=%d timestamp=%s for block from height=%d timestamp=%s\n",
nStakeModifier, nStakeModifierHeight,
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 hashTarget=%s hashProof=%s\n",
nStakeModifier,
nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx,
targetProofOfStake.ToString().c_str(), hashProofOfStake.ToString().c_str());
}
// Now check if proof-of-stake hash meets target protocol
if (CBigNum(hashProofOfStake) > bnCoinDayWeight * bnTargetPerCoinDay)
return false;
if (fDebug && !fPrintProofOfStake)
{
printf("CheckStakeKernelHash() : using modifier 0x%016" PRIx64 " at height=%d timestamp=%s for block from height=%d timestamp=%s\n",
nStakeModifier, nStakeModifierHeight,
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 hashTarget=%s hashProof=%s\n",
nStakeModifier,
nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx,
targetProofOfStake.ToString().c_str(), hashProofOfStake.ToString().c_str());
}
return true;
}
#ifdef USE_ASM
#ifndef __i386__
// kernel padding
static const uint32_t block1_suffix[9] = { 0x80000000, 0, 0, 0, 0, 0, 0, 0, 0x000000e0 };
// hash padding
static const uint32_t block2_suffix[8] = { 0x80000000, 0, 0, 0, 0, 0, 0, 0x00000100 };
#endif
// 4-way kernel padding
static const uint32_t block1_suffix_4way[4 * 9] = {
0x80000000, 0x80000000, 0x80000000, 0x80000000,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0x000000e0, 0x000000e0, 0x000000e0, 0x000000e0
};
// 4-way hash padding
static const uint32_t block2_suffix_4way[4 * 8] = {
0x80000000, 0x80000000, 0x80000000, 0x80000000,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0x00000100, 0x00000100, 0x00000100, 0x00000100
};
#ifdef __x86_64__
// 8-way kernel padding
static const uint32_t block1_suffix_8way[8 * 9] = {
0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0x000000e0, 0x000000e0, 0x000000e0, 0x000000e0, 0x000000e0, 0x000000e0, 0x000000e0, 0x000000e0
};
// 8-way hash padding
static const uint32_t block2_suffix_8way[8 * 8] = {
0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0x000000e0, 0x000000e0, 0x000000e0, 0x000000e0, 0x000000e0, 0x000000e0, 0x000000e0, 0x000000e0
};
#endif
// Sha256 initial state
static const uint32_t sha256_initial[8] = { 0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19 };
#ifndef __i386__
extern "C" void sha256_transform(uint32_t *state, const uint32_t *block, int swap);
#endif
#if defined(__i386__) || defined(__x86_64__)
#include <immintrin.h>
extern "C" int sha256_use_ssse3();
bool fUseSSSE3 = sha256_use_ssse3() != 0;
inline void copyrow8_swap32(uint32_t *to, uint32_t *from)
{
__m128i mask = _mm_set_epi8(12, 13, 14, 15, 8, 9, 10, 11, 4, 5, 6, 7, 0, 1, 2, 3);
_mm_storeu_si128((__m128i *)&to[0], _mm_shuffle_epi8(_mm_loadu_si128((__m128i *)&from[0]), mask));
_mm_storeu_si128((__m128i *)&to[4], _mm_shuffle_epi8(_mm_loadu_si128((__m128i *)&from[4]), mask));
}
inline void copyrow4_swap32(uint32_t *to, uint32_t *from)
{
if (!fUseSSSE3)
{
for (int i = 0; i < 4; i++)
to[i] = __builtin_bswap32(from[i]);
}
else
{
__m128i mask = _mm_set_epi8(12, 13, 14, 15, 8, 9, 10, 11, 4, 5, 6, 7, 0, 1, 2, 3);
_mm_storeu_si128((__m128i *)&to[0], _mm_shuffle_epi8(_mm_loadu_si128((__m128i *)&from[0]), mask));
}
}
#else
inline void copyrow4_swap32(uint32_t *to, uint32_t *from)
{
for (int i = 0; i < 4; i++)
to[i] = __builtin_bswap32(from[i]);
}
#endif
extern "C" int sha256_use_4way();
extern "C" void sha256_init_4way(uint32_t *state);
extern "C" void sha256_transform_4way(uint32_t *state, const uint32_t *block, int swap);
bool fUse4Way = sha256_use_4way() != 0;
#ifdef __x86_64__
extern "C" int sha256_use_8way();
extern "C" void sha256_init_8way(uint32_t *state);
extern "C" void sha256_transform_8way(uint32_t *state, const uint32_t *block, int swap);
bool fUse8Way = sha256_use_8way() != 0;
#endif
class ScanMidstateWorker
{
public:
ScanMidstateWorker()
{ }
ScanMidstateWorker(unsigned char *kernel, uint32_t nBits, uint32_t nInputTxTime, int64_t nValueIn, uint32_t nIntervalBegin, uint32_t nIntervalEnd)
: kernel(kernel), nBits(nBits), nInputTxTime(nInputTxTime), bnValueIn(nValueIn), nIntervalBegin(nIntervalBegin), nIntervalEnd(nIntervalEnd)
{
solutions = vector<std::pair<uint256,uint32_t> >();
}
#ifdef __x86_64__
void Do_8way()
{
SetThreadPriority(THREAD_PRIORITY_LOWEST);
// Compute maximum possible target to filter out majority of obviously insufficient hashes
CBigNum bnTargetPerCoinDay;
bnTargetPerCoinDay.SetCompact(nBits);
uint256 nMaxTarget = (bnTargetPerCoinDay * bnValueIn * nStakeMaxAge / COIN / nOneDay).getuint256();
uint32_t blocks1[8 * 16] __attribute__((aligned(16)));
uint32_t blocks2[8 * 16] __attribute__((aligned(16)));
uint32_t candidates[8 * 8] __attribute__((aligned(16)));
vector<uint32_t> vRow = vector<uint32_t>(8);
uint32_t *pnKernel = (uint32_t *) kernel;
for(int i = 0; i < 7; i++)
{
fill(vRow.begin(), vRow.end(), pnKernel[i]);
copyrow8_swap32(&blocks1[i*8], &vRow[0]);
}
memcpy(&blocks1[56], &block1_suffix_8way[0], 36*8); // sha256 padding
memcpy(&blocks2[64], &block2_suffix_8way[0], 32*8);
uint32_t nHashes[8];
uint32_t nTimeStamps[8];
// Search forward in time from the given timestamp
// Stopping search in case of shutting down
for (uint32_t nTimeTx=nIntervalBegin, nMaxTarget32 = nMaxTarget.Get32(7); nTimeTx<nIntervalEnd && !fShutdown; nTimeTx +=8)
{
sha256_init_8way(blocks2);
sha256_init_8way(candidates);
nTimeStamps[0] = nTimeTx;
nTimeStamps[1] = nTimeTx+1;
nTimeStamps[2] = nTimeTx+2;
nTimeStamps[3] = nTimeTx+3;
nTimeStamps[4] = nTimeTx+4;
nTimeStamps[5] = nTimeTx+5;
nTimeStamps[6] = nTimeTx+6;
nTimeStamps[7] = nTimeTx+7;
copyrow8_swap32(&blocks1[24], &nTimeStamps[0]); // Kernel timestamps
sha256_transform_8way(&blocks2[0], &blocks1[0], 0); // first hashing
sha256_transform_8way(&candidates[0], &blocks2[0], 0); // second hashing
copyrow8_swap32(&nHashes[0], &candidates[56]);
for(int nResult = 0; nResult < 8; nResult++)
{
if (nHashes[nResult] <= nMaxTarget32) // Possible hit
{
uint256 nHashProofOfStake = 0;
uint32_t *pnHashProofOfStake = (uint32_t *) &nHashProofOfStake;
for (int i = 0; i < 7; i++)
pnHashProofOfStake[i] = __builtin_bswap32(candidates[(i*8) + nResult]);
pnHashProofOfStake[7] = nHashes[nResult];
CBigNum bnCoinDayWeight = bnValueIn * GetWeight((int64_t)nInputTxTime, (int64_t)nTimeStamps[nResult]) / COIN / nOneDay;
CBigNum bnTargetProofOfStake = bnCoinDayWeight * bnTargetPerCoinDay;
if (bnTargetProofOfStake >= CBigNum(nHashProofOfStake))
solutions.push_back(std::pair<uint256,uint32_t>(nHashProofOfStake, nTimeStamps[nResult]));
}
}
}
}
#endif
void Do_4way()
{
SetThreadPriority(THREAD_PRIORITY_LOWEST);
// Compute maximum possible target to filter out majority of obviously insufficient hashes
CBigNum bnTargetPerCoinDay;
bnTargetPerCoinDay.SetCompact(nBits);
uint256 nMaxTarget = (bnTargetPerCoinDay * bnValueIn * nStakeMaxAge / COIN / nOneDay).getuint256();
uint32_t blocks1[4 * 16] __attribute__((aligned(16)));
uint32_t blocks2[4 * 16] __attribute__((aligned(16)));
uint32_t candidates[4 * 8] __attribute__((aligned(16)));
vector<uint32_t> vRow = vector<uint32_t>(4);
uint32_t *pnKernel = (uint32_t *) kernel;
for(int i = 0; i < 7; i++)
{
fill(vRow.begin(), vRow.end(), pnKernel[i]);
copyrow4_swap32(&blocks1[i*4], &vRow[0]);
}
memcpy(&blocks1[28], &block1_suffix_4way[0], 36*4); // sha256 padding
memcpy(&blocks2[32], &block2_suffix_4way[0], 32*4);
uint32_t nHashes[4];
uint32_t nTimeStamps[4];
// Search forward in time from the given timestamp
// Stopping search in case of shutting down
for (uint32_t nTimeTx=nIntervalBegin, nMaxTarget32 = nMaxTarget.Get32(7); nTimeTx<nIntervalEnd && !fShutdown; nTimeTx +=4)
{
sha256_init_4way(blocks2);
sha256_init_4way(candidates);
nTimeStamps[0] = nTimeTx;
nTimeStamps[1] = nTimeTx+1;
nTimeStamps[2] = nTimeTx+2;
nTimeStamps[3] = nTimeTx+3;
copyrow4_swap32(&blocks1[24], &nTimeStamps[0]); // Kernel timestamps
sha256_transform_4way(&blocks2[0], &blocks1[0], 0); // first hashing
sha256_transform_4way(&candidates[0], &blocks2[0], 0); // second hashing
copyrow4_swap32(&nHashes[0], &candidates[28]);
for(int nResult = 0; nResult < 4; nResult++)
{
if (nHashes[nResult] <= nMaxTarget32) // Possible hit
{
uint256 nHashProofOfStake = 0;
uint32_t *pnHashProofOfStake = (uint32_t *) &nHashProofOfStake;
for (int i = 0; i < 7; i++)
pnHashProofOfStake[i] = __builtin_bswap32(candidates[(i*4) + nResult]);
pnHashProofOfStake[7] = nHashes[nResult];
CBigNum bnCoinDayWeight = bnValueIn * GetWeight((int64_t)nInputTxTime, (int64_t)nTimeStamps[nResult]) / COIN / nOneDay;
CBigNum bnTargetProofOfStake = bnCoinDayWeight * bnTargetPerCoinDay;
if (bnTargetProofOfStake >= CBigNum(nHashProofOfStake))
solutions.push_back(std::pair<uint256,uint32_t>(nHashProofOfStake, nTimeStamps[nResult]));
}
}
}
}
void Do_oneway()
{
SetThreadPriority(THREAD_PRIORITY_LOWEST);
// Compute maximum possible target to filter out majority of obviously insufficient hashes
CBigNum bnTargetPerCoinDay;
bnTargetPerCoinDay.SetCompact(nBits);
uint256 nMaxTarget = (bnTargetPerCoinDay * bnValueIn * nStakeMaxAge / COIN / nOneDay).getuint256();
#ifdef __i386__
SHA256_CTX ctx, workerCtx;
// Init new sha256 context and update it
// with first 24 bytes of kernel
SHA256_Init(&ctx);
SHA256_Update(&ctx, kernel, 8 + 16);
workerCtx = ctx; // save context
// Sha256 result buffer
uint32_t hashProofOfStake[8];
uint256 *pnHashProofOfStake = (uint256 *)&hashProofOfStake;
// Search forward in time from the given timestamp
// Stopping search in case of shutting down
for (uint32_t nTimeTx=nIntervalBegin, nMaxTarget32 = nMaxTarget.Get32(7); nTimeTx<nIntervalEnd && !fShutdown; nTimeTx++)
{
// Complete first hashing iteration
uint256 hash1;
SHA256_Update(&ctx, (unsigned char*)&nTimeTx, 4);
SHA256_Final((unsigned char*)&hash1, &ctx);
// Restore context
ctx = workerCtx;
// Finally, calculate kernel hash
SHA256((unsigned char*)&hash1, sizeof(hashProofOfStake), (unsigned char*)&hashProofOfStake);
// Skip if hash doesn't satisfy the maximum target
if (hashProofOfStake[7] > nMaxTarget32)
continue;
CBigNum bnCoinDayWeight = bnValueIn * GetWeight((int64_t)nInputTxTime, (int64_t)nTimeTx) / COIN / nOneDay;
CBigNum bnTargetProofOfStake = bnCoinDayWeight * bnTargetPerCoinDay;
if (bnTargetProofOfStake >= CBigNum(*pnHashProofOfStake))
solutions.push_back(std::pair<uint256,uint32_t>(*pnHashProofOfStake, nTimeTx));
}
#else
uint32_t block1[16] __attribute__((aligned(16)));
uint32_t block2[16] __attribute__((aligned(16)));
uint32_t candidate[8] __attribute__((aligned(16)));
memcpy(&block1[7], &block1_suffix[0], 36); // sha256 padding
memcpy(&block2[8], &block2_suffix[0], 32);
uint32_t *pnKernel = (uint32_t *) kernel;
copyrow4_swap32(&block1[0], pnKernel);
block1[4] = __builtin_bswap32(pnKernel[4]);
block1[5] = __builtin_bswap32(pnKernel[5]);
// Search forward in time from the given timestamp
// Stopping search in case of shutting down
for (uint32_t nTimeTx=nIntervalBegin, nMaxTarget32 = nMaxTarget.Get32(7); nTimeTx<nIntervalEnd && !fShutdown; nTimeTx++)
{
memcpy(&block2[0], &sha256_initial[0], 32);
memcpy(&candidate[0], &sha256_initial[0], 32);
block1[6] = __builtin_bswap32(nTimeTx);
sha256_transform(&block2[0], &block1[0], 0); // first hashing
sha256_transform(&candidate[0], &block2[0], 0); // second hashing
uint32_t nHash7 = __builtin_bswap32(candidate[7]);
// Skip if hash doesn't satisfy the maximum target
if (nHash7 > nMaxTarget32)
continue;
uint256 nHashProofOfStake;
uint32_t *pnHashProofOfStake = (uint32_t *) &nHashProofOfStake;
for (int i = 0; i < 7; i++)
pnHashProofOfStake[i] = __builtin_bswap32(candidate[i]);
pnHashProofOfStake[7] = nHash7;
CBigNum bnCoinDayWeight = bnValueIn * GetWeight((int64_t)nInputTxTime, (int64_t)nTimeTx) / COIN / nOneDay;
CBigNum bnTargetProofOfStake = bnCoinDayWeight * bnTargetPerCoinDay;
if (bnTargetProofOfStake >= CBigNum(nHashProofOfStake))
solutions.push_back(std::pair<uint256,uint32_t>(nHashProofOfStake, nTimeTx));
}
#endif
}
void Do()
{
#ifdef __x86_64__
if (false && fUse8Way) // disable for now
{
Do_8way();
return;
}
#endif
if (fUse4Way)
{
Do_4way();
return;
}
Do_oneway();
}
vector<std::pair<uint256,uint32_t> >& GetSolutions()
{
return solutions;
}
private:
std::vector<std::pair<uint256,uint32_t> > solutions;
uint8_t *kernel;
uint32_t nBits;
uint32_t nInputTxTime;
CBigNum bnValueIn;
uint32_t nIntervalBegin;
uint32_t nIntervalEnd;
};
#else
class ScanMidstateWorker
{
public:
ScanMidstateWorker()
{ }
ScanMidstateWorker(unsigned char *kernel, uint32_t nBits, uint32_t nInputTxTime, int64_t nValueIn, uint32_t nIntervalBegin, uint32_t nIntervalEnd)
: nBits(nBits), nInputTxTime(nInputTxTime), bnValueIn(nValueIn), nIntervalBegin(nIntervalBegin), nIntervalEnd(nIntervalEnd)
{
// Init new sha256 context and update it
// with first 24 bytes of kernel
SHA256_Init(&workerCtx);
SHA256_Update(&workerCtx, kernel, 8 + 16);
solutions = vector<std::pair<uint256,uint32_t> >();
}
void Do()
{
SetThreadPriority(THREAD_PRIORITY_LOWEST);
SHA256_CTX ctx = workerCtx;
// Sha256 result buffer
uint32_t hashProofOfStake[8];
// Compute maximum possible target to filter out majority of obviously insufficient hashes
CBigNum bnTargetPerCoinDay;
bnTargetPerCoinDay.SetCompact(nBits);
uint256 nMaxTarget = (bnTargetPerCoinDay * bnValueIn * nStakeMaxAge / COIN / nOneDay).getuint256(),
*pnHashProofOfStake = (uint256 *)&hashProofOfStake;
// Search forward in time from the given timestamp
// Stopping search in case of shutting down
for (uint32_t nTimeTx=nIntervalBegin, nMaxTarget32 = nMaxTarget.Get32(7); nTimeTx<nIntervalEnd && !fShutdown; nTimeTx++)
{
// Complete first hashing iteration
uint256 hash1;
SHA256_Update(&ctx, (unsigned char*)&nTimeTx, 4);
SHA256_Final((unsigned char*)&hash1, &ctx);
// Restore context
ctx = workerCtx;
// Finally, calculate kernel hash
SHA256((unsigned char*)&hash1, sizeof(hashProofOfStake), (unsigned char*)&hashProofOfStake);
// Skip if hash doesn't satisfy the maximum target
if (hashProofOfStake[7] > nMaxTarget32)
continue;
CBigNum bnCoinDayWeight = bnValueIn * GetWeight((int64_t)nInputTxTime, (int64_t)nTimeTx) / COIN / nOneDay;
CBigNum bnTargetProofOfStake = bnCoinDayWeight * bnTargetPerCoinDay;
if (bnTargetProofOfStake >= CBigNum(*pnHashProofOfStake))
solutions.push_back(std::pair<uint256,uint32_t>(*pnHashProofOfStake, nTimeTx));
}
}
vector<std::pair<uint256,uint32_t> >& GetSolutions()
{
return solutions;
}
private:
SHA256_CTX workerCtx;
std::vector<std::pair<uint256,uint32_t> > solutions;
uint32_t nBits;
uint32_t nInputTxTime;
CBigNum bnValueIn;
uint32_t nIntervalBegin;
uint32_t nIntervalEnd;
};
#endif
// Scan given kernel for solution
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)
{
// TODO: custom threads amount
uint32_t nThreads = boost::thread::hardware_concurrency();
uint32_t nPart = (SearchInterval.second - SearchInterval.first) / nThreads;
ScanMidstateWorker *workers = new ScanMidstateWorker[nThreads];
boost::thread_group group;
for(size_t i = 0; i < nThreads; i++)
{
uint32_t nBegin = SearchInterval.first + nPart * i;
uint32_t nEnd = SearchInterval.first + nPart * (i + 1);
workers[i] = ScanMidstateWorker(kernel, nBits, nInputTxTime, nValueIn, nBegin, nEnd);
boost::function<void()> workerFnc = boost::bind(&ScanMidstateWorker::Do, &workers[i]);
group.create_thread(workerFnc);
}
group.join_all();
solutions.clear();
for(size_t i = 0; i < nThreads; i++)
{
std::vector<std::pair<uint256, uint32_t> > ws = workers[i].GetSolutions();
solutions.insert(solutions.end(), ws.begin(), ws.end());
}
delete [] workers;
if (solutions.size() == 0)
{
// no solutions
return false;
}
return true;
}
// Scan given midstate for solution
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)
{
CBigNum bnTargetPerCoinDay;
bnTargetPerCoinDay.SetCompact(nBits);
// Get maximum possible target to filter out the majority of obviously insufficient hashes
CBigNum bnMaxTargetPerCoinDay = bnTargetPerCoinDay * CBigNum(nValueIn) * nStakeMaxAge / COIN / nOneDay;
uint256 maxTarget = bnMaxTargetPerCoinDay.getuint256();
SHA256_CTX ctxCopy = ctx;
// Search backward 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);
// Restore context
ctxCopy = ctx;
// 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)nInputTxTime, (int64_t)nTimeTx) / COIN / nOneDay;
CBigNum bnTargetProofOfStake = bnCoinDayWeight * bnTargetPerCoinDay;
if (bnTargetProofOfStake >= CBigNum(hashProofOfStake))
{
solution.first = hashProofOfStake;
solution.second = nTimeTx;
return true;
}
}
return false;
}
// Check kernel hash target and coinstake signature
bool CheckProofOfStake(const CTransaction& tx, unsigned int nBits, uint256& hashProofOfStake, uint256& targetProofOfStake)
{
if (!tx.IsCoinStake())
return error("CheckProofOfStake() : called on non-coinstake %s", tx.GetHash().ToString().c_str());
// Kernel (input 0) must match the stake hash target per coin age (nBits)
const CTxIn& txin = tx.vin[0];
// First try finding the previous transaction in database
CTxDB txdb("r");
CTransaction txPrev;
CTxIndex txindex;
if (!txPrev.ReadFromDisk(txdb, txin.prevout, txindex))
return tx.DoS(1, error("CheckProofOfStake() : INFO: read txPrev failed")); // previous transaction not in main chain, may occur during initial download