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// Copyright (c) 2012-2019 The Peercoin developers
// 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 "db.h"
#include "txdb.h"
using namespace std;
// Protocol switch time of v0.3 kernel protocol
unsigned int nProtocolV03SwitchTime = 1363800000;
unsigned int nProtocolV03TestSwitchTime = 1359781000;
// Protocol switch time of v0.4 kernel protocol
unsigned int nProtocolV04SwitchTime = 1399300000;
unsigned int nProtocolV04TestSwitchTime = 1395700000;
// Protocol switch time of v0.5 kernel protocol
unsigned int nProtocolV05SwitchTime = 1461700000;
unsigned int nProtocolV05TestSwitchTime = 1447700000;
// Protocol switch time of v0.6 kernel protocol
// supermajority hardfork: actual fork will happen later than switch time
const unsigned int nProtocolV06SwitchTime = 1513050000; // Tue 12 Dec 03:40:00 UTC 2017
const unsigned int nProtocolV06TestSwitchTime = 1508198400; // Tue 17 Oct 00:00:00 UTC 2017
// Protocol switch time for 0.7 kernel protocol
const unsigned int nProtocolV07SwitchTime = 1552392000; // Tue 12 Mar 12:00:00 UTC 2019
const unsigned int nProtocolV07TestSwitchTime = 1541505600; // Tue 06 Nov 12:00:00 UTC 2018
// Modifier interval: time to elapse before new modifier is computed
// Set to 6-hour for production network and 20-minute for test network
unsigned int nModifierInterval = MODIFIER_INTERVAL;
// Hard checkpoints of stake modifiers to ensure they are deterministic
static std::map<int, unsigned int> mapStakeModifierCheckpoints =
boost::assign::map_list_of
( 0, 0x0e00670bu )
( 19080, 0xad4e4d29u )
( 30583, 0xdc7bf136u )
( 99999, 0xf555cfd2u )
(219999, 0x91b7444du )
(336000, 0x6c3c8048u )
(371850, 0x9b850bdfu )
(407813, 0x46fe50b5u )
(420000, 0xc1c89fa6u )
;
static std::map<int, unsigned int> mapStakeModifierTestnetCheckpoints =
boost::assign::map_list_of
( 0, 0x0e00670bu )
( 19080, 0x3711dc3au )
( 30583, 0xb480fadeu )
( 99999, 0x9a62eaecu )
(219999, 0xeafe96c3u )
(336000, 0x8330dc09u )
(372751, 0xafb94e2fu )
(382019, 0x7f5cf5ebu )
(390390, 0xc6c0ea98u )
;
// Whether the given coinstake is subject to new v0.3 protocol
bool IsProtocolV03(unsigned int nTimeCoinStake)
{
return (nTimeCoinStake >= (fTestNet? nProtocolV03TestSwitchTime : nProtocolV03SwitchTime));
}
// Whether the given block is subject to new v0.4 protocol
bool IsProtocolV04(unsigned int nTimeBlock)
{
return (nTimeBlock >= (fTestNet? nProtocolV04TestSwitchTime : nProtocolV04SwitchTime));
}
// Whether the given transaction is subject to new v0.5 protocol
bool IsProtocolV05(unsigned int nTimeTx)
{
return (nTimeTx >= (fTestNet? nProtocolV05TestSwitchTime : nProtocolV05SwitchTime));
}
// Whether a given block is subject to new v0.6 protocol
// Test against previous block index! (always available)
bool IsProtocolV06(const CBlockIndex* pindexPrev)
{
if (pindexPrev->nTime < (fTestNet? nProtocolV06TestSwitchTime : nProtocolV06SwitchTime))
return false;
// if 900 of the last 1,000 blocks are version 2 or greater (90/100 if testnet):
// Soft-forking PoS can be dangerous if the super majority is too low
// The stake majority will decrease after the fork
// since only coindays of updated nodes will get destroyed.
if ((!fTestNet && CBlockIndex::IsSuperMajority(2, pindexPrev, 900, 1000)) ||
(fTestNet && CBlockIndex::IsSuperMajority(2, pindexPrev, 90, 100)))
return true;
return false;
}
// Whether a given transaction is subject to new v0.7 protocol
bool IsProtocolV07(unsigned int nTimeTx)
{
return (nTimeTx >= (fTestNet? nProtocolV07TestSwitchTime : nProtocolV07SwitchTime));
}
// Get the last stake modifier and its generation time from a given block
static bool GetLastStakeModifier(const CBlockIndex* pindex, uint64& nStakeModifier, int64& 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 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 GetStakeModifierSelectionInterval()
{
int64 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, uint256> >& vSortedByTimestamp,
map<uint256, const CBlockIndex*>& mapSelectedBlocks,
int64 nSelectionIntervalStop, uint64 nStakeModifierPrev,
const CBlockIndex** pindexSelected)
{
bool fSelected = false;
uint256 hashBest = 0;
*pindexSelected = (const CBlockIndex*) 0;
BOOST_FOREACH(const PAIRTYPE(int64, 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& nStakeModifier, bool& fGeneratedStakeModifier)
{
const CBlockIndex* pindexPrev = pindexCurrent->pprev;
nStakeModifier = 0;
fGeneratedStakeModifier = false;
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 nModifierTime = 0;
if (!GetLastStakeModifier(pindexPrev, nStakeModifier, nModifierTime))
return error("ComputeNextStakeModifier: unable to get last modifier");
if (fDebug)
{
printf("ComputeNextStakeModifier: prev modifier=0x%016" PRI64x" 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)
{
// v0.4+ requires current block timestamp also be in a different modifier interval
if (IsProtocolV04(pindexCurrent->nTime))
{
if (fDebug)
{
printf("ComputeNextStakeModifier: (v0.4+) 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: v0.3 modifier at block %s not meeting v0.4+ protocol: 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, uint256> > vSortedByTimestamp;
vSortedByTimestamp.reserve(64 * nModifierInterval / STAKE_TARGET_SPACING);
int64 nSelectionInterval = GetStakeModifierSelectionInterval();
int64 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 nStakeModifierNew = 0;
int64 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)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" PRI64x" time=%s\n", nStakeModifierNew, DateTimeStrFormat(pindexPrev->GetBlockTime()).c_str());
}
nStakeModifier = nStakeModifierNew;
fGeneratedStakeModifier = true;
return true;
}
// V0.5: Stake modifier used to hash for a stake kernel is chosen as the stake
// modifier that is (nStakeMinAge minus a selection interval) earlier than the
// stake, thus at least a selection interval later than the coin generating the // kernel, as the generating coin is from at least nStakeMinAge ago.
static bool GetKernelStakeModifierV05(unsigned int nTimeTx, uint64& nStakeModifier, int& nStakeModifierHeight, int64& nStakeModifierTime, bool fPrintProofOfStake)
{
const CBlockIndex* pindex = pindexBest;
nStakeModifierHeight = pindex->nHeight;
nStakeModifierTime = pindex->GetBlockTime();
int64 nStakeModifierSelectionInterval = GetStakeModifierSelectionInterval();
if (nStakeModifierTime + nStakeMinAge - nStakeModifierSelectionInterval <= (int64) nTimeTx)
{
// Best block is still more than
// (nStakeMinAge minus a selection interval) older than kernel timestamp
if (fPrintProofOfStake)
return error("GetKernelStakeModifier() : best block %s at height %d too old for stake",
pindex->GetBlockHash().ToString().c_str(), pindex->nHeight);
else
return false;
}
// loop to find the stake modifier earlier by
// (nStakeMinAge minus a selection interval)
while (nStakeModifierTime + nStakeMinAge - nStakeModifierSelectionInterval >(int64) nTimeTx)
{
if (!pindex->pprev)
{ // reached genesis block; should not happen
return error("GetKernelStakeModifier() : reached genesis block");
}
pindex = pindex->pprev;
if (pindex->GeneratedStakeModifier())
{
nStakeModifierHeight = pindex->nHeight;
nStakeModifierTime = pindex->GetBlockTime();
}
}
nStakeModifier = pindex->nStakeModifier;
return true;
}
// V0.3: 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 GetKernelStakeModifierV03(uint256 hashBlockFrom, uint64& nStakeModifier, int& nStakeModifierHeight, int64& 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 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;
}
// Get the stake modifier specified by the protocol to hash for a stake kernel
static bool GetKernelStakeModifier(uint256 hashBlockFrom, unsigned int nTimeTx, uint64& nStakeModifier, int& nStakeModifierHeight, int64& nStakeModifierTime, bool fPrintProofOfStake)
{
if (IsProtocolV05(nTimeTx))
return GetKernelStakeModifierV05(nTimeTx, nStakeModifier, nStakeModifierHeight, nStakeModifierTime, fPrintProofOfStake);
else
return GetKernelStakeModifierV03(hashBlockFrom, nStakeModifier, nStakeModifierHeight, nStakeModifierTime, fPrintProofOfStake);
}
// 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:
// (v0.5) uses dynamic stake modifier around 21 days before the kernel,
// versus static stake modifier about 9 days after the staked
// coin (txPrev) used in v0.3
// (v0.3) scrambles computation to make it very difficult to precompute
// future proof-of-stake at the time of the coin's confirmation
// (v0.2) nBits (deprecated): encodes all past block timestamps
// 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(unsigned int nBits, const CBlockHeader& blockFrom, unsigned int nTxPrevOffset, const CTransaction& txPrev, const COutPoint& prevout, unsigned int nTimeTx, uint256& hashProofOfStake, bool fPrintProofOfStake)
{
if (nTimeTx < txPrev.nTime) // Transaction timestamp violation
return error("CheckStakeKernelHash() : nTime violation");
unsigned int nTimeBlockFrom = blockFrom.GetBlockTime();
if (nTimeBlockFrom + nStakeMinAge > nTimeTx) // Min age requirement
return error("CheckStakeKernelHash() : min age violation");
CBigNum bnTargetPerCoinDay;
bnTargetPerCoinDay.SetCompact(nBits);
int64 nValueIn = txPrev.vout[prevout.n].nValue;
// v0.3 protocol 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
int64 nTimeWeight = min((int64)nTimeTx - txPrev.nTime, (int64)STAKE_MAX_AGE) - (IsProtocolV03(nTimeTx)? nStakeMinAge : 0);
CBigNum bnCoinDayWeight = CBigNum(nValueIn) * nTimeWeight / COIN / (24 * 60 * 60);
// Calculate hash
CDataStream ss(SER_GETHASH, 0);
uint64 nStakeModifier = 0;
int nStakeModifierHeight = 0;
int64 nStakeModifierTime = 0;
if (IsProtocolV03(nTimeTx)) // v0.3 protocol
{
if (!GetKernelStakeModifier(blockFrom.GetHash(), nTimeTx, nStakeModifier, nStakeModifierHeight, nStakeModifierTime, fPrintProofOfStake))
return false;
ss << nStakeModifier;
}
else // v0.2 protocol
{
ss << nBits;
}
ss << nTimeBlockFrom << nTxPrevOffset << txPrev.nTime << prevout.n << nTimeTx;
hashProofOfStake = Hash(ss.begin(), ss.end());
if (fPrintProofOfStake)
{
if (IsProtocolV03(nTimeTx))
printf("CheckStakeKernelHash() : using modifier 0x%016" PRI64x" at height=%d timestamp=%s for block from height=%d timestamp=%s\n",
nStakeModifier, nStakeModifierHeight,
DateTimeStrFormat(nStakeModifierTime).c_str(),
mapBlockIndex[blockFrom.GetHash()]->nHeight,
DateTimeStrFormat(blockFrom.GetBlockTime()).c_str());
printf("CheckStakeKernelHash() : check protocol=%s modifier=0x%016" PRI64x" nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashProof=%s\n",
IsProtocolV05(nTimeTx)? "0.5" : (IsProtocolV03(nTimeTx)? "0.3" : "0.2"),
IsProtocolV03(nTimeTx)? nStakeModifier : (uint64) nBits,
nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx,
hashProofOfStake.ToString().c_str());
}
// Now check if proof-of-stake hash meets target protocol
if (CBigNum(hashProofOfStake) > bnCoinDayWeight * bnTargetPerCoinDay)
return false;
if (fDebug && !fPrintProofOfStake)
{
if (IsProtocolV03(nTimeTx))
printf("CheckStakeKernelHash() : using modifier 0x%016" PRI64x" at height=%d timestamp=%s for block from height=%d timestamp=%s\n",
nStakeModifier, nStakeModifierHeight,
DateTimeStrFormat(nStakeModifierTime).c_str(),
mapBlockIndex[blockFrom.GetHash()]->nHeight,
DateTimeStrFormat(blockFrom.GetBlockTime()).c_str());
printf("CheckStakeKernelHash() : pass protocol=%s modifier=0x%016" PRI64x" nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashProof=%s\n",
IsProtocolV03(nTimeTx)? "0.3" : "0.2",
IsProtocolV03(nTimeTx)? nStakeModifier : (uint64) nBits,
nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx,
hashProofOfStake.ToString().c_str());
}
return true;
}
// Check kernel hash target and coinstake signature
bool CheckProofOfStake(CValidationState &state, const CTransaction& tx, unsigned int nBits, uint256& hashProofOfStake)
{
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];
// Transaction index is required to get to block header
if (!fTxIndex)
return error("CheckProofOfStake() : transaction index not available");
// Get transaction index for the previous transaction
CDiskTxPos postx;
if (!pblocktree->ReadTxIndex(txin.prevout.hash, postx))
return error("CheckProofOfStake() : tx index not found"); // tx index not found
// Read txPrev and header of its block
CBlockHeader header;
CTransaction txPrev;
{
CAutoFile file(OpenBlockFile(postx, true), SER_DISK, CLIENT_VERSION);
try {
file >> header;
fseek(file, postx.nTxOffset, SEEK_CUR);
file >> txPrev;
} catch (std::exception &e) {
return error("%s() : deserialize or I/O error in CheckProofOfStake()", __PRETTY_FUNCTION__);
}
if (txPrev.GetHash() != txin.prevout.hash)
return error("%s() : txid mismatch in CheckProofOfStake()", __PRETTY_FUNCTION__);
}
// Verify signature
CCoins coins(txPrev, 0);
if (!VerifySignature(coins, tx, 0, SCRIPT_VERIFY_P2SH, 0))
return state.DoS(100, error("CheckProofOfStake() : VerifySignature failed on coinstake %s", tx.GetHash().ToString().c_str()));
if (!CheckStakeKernelHash(nBits, header, postx.nTxOffset + sizeof(CBlockHeader), txPrev, txin.prevout, tx.nTime, hashProofOfStake, fDebug))
return state.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
return true;
}
// Check whether the coinstake timestamp meets protocol
bool CheckCoinStakeTimestamp(int64 nTimeBlock, int64 nTimeTx)
{
if (IsProtocolV03(nTimeTx)) // v0.3 protocol
return (nTimeBlock == nTimeTx);
else // v0.2 protocol
return ((nTimeTx <= nTimeBlock) && (nTimeBlock <= nTimeTx + nMaxClockDrift));
}
// Get stake modifier checksum
unsigned int GetStakeModifierChecksum(const CBlockIndex* pindex)
{
assert (pindex->pprev || pindex->GetBlockHash() == hashGenesisBlock);
// Hash previous checksum with flags, hashProofOfStake and nStakeModifier
CDataStream ss(SER_GETHASH, 0);
if (pindex->pprev)
ss << pindex->pprev->nStakeModifierChecksum;
ss << pindex->nFlags << pindex->hashProofOfStake << pindex->nStakeModifier;
uint256 hashChecksum = Hash(ss.begin(), ss.end());
hashChecksum >>= (256 - 32);
return hashChecksum.Get64();
}
// Check stake modifier hard checkpoints
bool CheckStakeModifierCheckpoints(int nHeight, unsigned int nStakeModifierChecksum)
{
if (fTestNet && mapStakeModifierTestnetCheckpoints.count(nHeight))
return nStakeModifierChecksum == mapStakeModifierTestnetCheckpoints[nHeight];
if (!fTestNet && mapStakeModifierCheckpoints.count(nHeight))
return nStakeModifierChecksum == mapStakeModifierCheckpoints[nHeight];
return true;
}
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