Make sure we always have a node to do IBD from
[novacoin.git] / src / main.cpp
index 894bad6..9a521fe 100644 (file)
@@ -6,15 +6,18 @@
 #include "alert.h"
 #include "checkpoints.h"
 #include "db.h"
+#include "txdb.h"
 #include "net.h"
 #include "init.h"
 #include "ui_interface.h"
+#include "checkqueue.h"
 #include "kernel.h"
-#include "scrypt_mine.h"
+#include "zerocoin/Zerocoin.h"
 #include <boost/algorithm/string/replace.hpp>
 #include <boost/filesystem.hpp>
 #include <boost/filesystem/fstream.hpp>
 
+
 using namespace std;
 using namespace boost;
 
@@ -32,6 +35,7 @@ unsigned int nTransactionsUpdated = 0;
 
 map<uint256, CBlockIndex*> mapBlockIndex;
 set<pair<COutPoint, unsigned int> > setStakeSeen;
+libzerocoin::Params* ZCParams;
 
 CBigNum bnProofOfWorkLimit(~uint256(0) >> 20); // "standard" scrypt target limit for proof of work, results with 0,000244140625 proof-of-work difficulty
 CBigNum bnProofOfStakeLegacyLimit(~uint256(0) >> 24); // proof of stake target limit from block #15000 and until 20 June 2013, results with 0,00390625 proof of stake difficulty
@@ -41,8 +45,8 @@ uint256 nPoWBase = uint256("0x00000000ffff00000000000000000000000000000000000000
 
 CBigNum bnProofOfWorkLimitTestNet(~uint256(0) >> 16);
 
-unsigned int nStakeMinAge = 60 * 60 * 24 * 30; // 30 days as minimum age for coin age
-unsigned int nStakeMaxAge = 60 * 60 * 24 * 90; // 90 days as stake age of full weight
+unsigned int nStakeMinAge = 60 * 60 * 24 * 30; // 30 days as zero time weight
+unsigned int nStakeMaxAge = 60 * 60 * 24 * 90; // 90 days as full weight
 unsigned int nStakeTargetSpacing = 10 * 60; // 10-minute stakes spacing
 unsigned int nModifierInterval = 6 * 60 * 60; // time to elapse before new modifier is computed
 
@@ -56,6 +60,7 @@ uint256 nBestInvalidTrust = 0;
 uint256 hashBestChain = 0;
 CBlockIndex* pindexBest = NULL;
 int64 nTimeBestReceived = 0;
+int nScriptCheckThreads = 0;
 
 CMedianFilter<int> cPeerBlockCounts(5, 0); // Amount of blocks that other nodes claim to have
 
@@ -64,8 +69,8 @@ multimap<uint256, CBlock*> mapOrphanBlocksByPrev;
 set<pair<COutPoint, unsigned int> > setStakeSeenOrphan;
 map<uint256, uint256> mapProofOfStake;
 
-map<uint256, CDataStream*> mapOrphanTransactions;
-map<uint256, map<uint256, CDataStream*> > mapOrphanTransactionsByPrev;
+map<uint256, CTransaction> mapOrphanTransactions;
+map<uint256, set<uint256> > mapOrphanTransactionsByPrev;
 
 // Constant stuff for coinbase transactions we create:
 CScript COINBASE_FLAGS;
@@ -74,7 +79,9 @@ const string strMessageMagic = "NovaCoin Signed Message:\n";
 
 // Settings
 int64 nTransactionFee = MIN_TX_FEE;
-bool fStakeUsePooledKeys = false;
+int64 nMinimumInputValue = MIN_TX_FEE;
+
+extern enum Checkpoints::CPMode CheckpointsMode;
 
 //////////////////////////////////////////////////////////////////////////////
 //
@@ -190,16 +197,12 @@ void ResendWalletTransactions()
 // mapOrphanTransactions
 //
 
-bool AddOrphanTx(const CDataStream& vMsg)
+bool AddOrphanTx(const CTransaction& tx)
 {
-    CTransaction tx;
-    CDataStream(vMsg) >> tx;
     uint256 hash = tx.GetHash();
     if (mapOrphanTransactions.count(hash))
         return false;
 
-    CDataStream* pvMsg = new CDataStream(vMsg);
-
     // Ignore big transactions, to avoid a
     // send-big-orphans memory exhaustion attack. If a peer has a legitimate
     // large transaction with a missing parent then we assume
@@ -207,16 +210,18 @@ bool AddOrphanTx(const CDataStream& vMsg)
     // have been mined or received.
     // 10,000 orphans, each of which is at most 5,000 bytes big is
     // at most 500 megabytes of orphans:
-    if (pvMsg->size() > 5000)
+
+    size_t nSize = tx.GetSerializeSize(SER_NETWORK, CTransaction::CURRENT_VERSION);
+
+    if (nSize > 5000)
     {
-        printf("ignoring large orphan tx (size: %"PRIszu", hash: %s)\n", pvMsg->size(), hash.ToString().substr(0,10).c_str());
-        delete pvMsg;
+        printf("ignoring large orphan tx (size: %"PRIszu", hash: %s)\n", nSize, hash.ToString().substr(0,10).c_str());
         return false;
     }
 
-    mapOrphanTransactions[hash] = pvMsg;
+    mapOrphanTransactions[hash] = tx;
     BOOST_FOREACH(const CTxIn& txin, tx.vin)
-        mapOrphanTransactionsByPrev[txin.prevout.hash].insert(make_pair(hash, pvMsg));
+        mapOrphanTransactionsByPrev[txin.prevout.hash].insert(hash);
 
     printf("stored orphan tx %s (mapsz %"PRIszu")\n", hash.ToString().substr(0,10).c_str(),
         mapOrphanTransactions.size());
@@ -227,16 +232,13 @@ void static EraseOrphanTx(uint256 hash)
 {
     if (!mapOrphanTransactions.count(hash))
         return;
-    const CDataStream* pvMsg = mapOrphanTransactions[hash];
-    CTransaction tx;
-    CDataStream(*pvMsg) >> tx;
+    const CTransaction& tx = mapOrphanTransactions[hash];
     BOOST_FOREACH(const CTxIn& txin, tx.vin)
     {
         mapOrphanTransactionsByPrev[txin.prevout.hash].erase(hash);
         if (mapOrphanTransactionsByPrev[txin.prevout.hash].empty())
             mapOrphanTransactionsByPrev.erase(txin.prevout.hash);
     }
-    delete pvMsg;
     mapOrphanTransactions.erase(hash);
 }
 
@@ -247,7 +249,7 @@ unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans)
     {
         // Evict a random orphan:
         uint256 randomhash = GetRandHash();
-        map<uint256, CDataStream*>::iterator it = mapOrphanTransactions.lower_bound(randomhash);
+        map<uint256, CTransaction>::iterator it = mapOrphanTransactions.lower_bound(randomhash);
         if (it == mapOrphanTransactions.end())
             it = mapOrphanTransactions.begin();
         EraseOrphanTx(it->first);
@@ -300,6 +302,8 @@ bool CTransaction::IsStandard() const
     if (nVersion > CTransaction::CURRENT_VERSION)
         return false;
 
+    unsigned int nDataOut = 0;
+    txnouttype whichType;
     BOOST_FOREACH(const CTxIn& txin, vin)
     {
         // Biggest 'standard' txin is a 3-signature 3-of-3 CHECKMULTISIG
@@ -309,13 +313,31 @@ bool CTransaction::IsStandard() const
             return false;
         if (!txin.scriptSig.IsPushOnly())
             return false;
+        if (!txin.scriptSig.HasCanonicalPushes()) {
+            return false;
+        }
     }
     BOOST_FOREACH(const CTxOut& txout, vout) {
-        if (!::IsStandard(txout.scriptPubKey))
-            return false;
-        if (txout.nValue == 0)
+        if (!::IsStandard(txout.scriptPubKey, whichType)) {
             return false;
+        }
+        if (whichType == TX_NULL_DATA)
+            nDataOut++;
+        else {
+            if (txout.nValue == 0) {
+                return false;
+            }
+            if (!txout.scriptPubKey.HasCanonicalPushes()) {
+                return false;
+            }
+        }
+    }
+
+    // only one OP_RETURN txout is permitted
+    if (nDataOut > 1) {
+        return false;
     }
+
     return true;
 }
 
@@ -355,7 +377,7 @@ bool CTransaction::AreInputsStandard(const MapPrevTx& mapInputs) const
         // beside "push data" in the scriptSig the
         // IsStandard() call returns false
         vector<vector<unsigned char> > stack;
-        if (!EvalScript(stack, vin[i].scriptSig, *this, i, 0))
+        if (!EvalScript(stack, vin[i].scriptSig, *this, i, false, 0))
             return false;
 
         if (whichType == TX_SCRIPTHASH)
@@ -476,12 +498,8 @@ bool CTransaction::CheckTransaction() const
         if (txout.IsEmpty() && !IsCoinBase() && !IsCoinStake())
             return DoS(100, error("CTransaction::CheckTransaction() : txout empty for user transaction"));
 
-        // NovaCoin: enforce minimum output amount for user transactions
-        // (and for all transactions until 20 Sep 2013)
-        if ((!IsCoinBase() || nTime < CHAINCHECKS_SWITCH_TIME)
-                && (!txout.IsEmpty()) && txout.nValue < MIN_TXOUT_AMOUNT)
-            return DoS(100, error("CTransaction::CheckTransaction() : txout.nValue below minimum"));
-
+        if (txout.nValue < 0)
+            return DoS(100, error("CTransaction::CheckTransaction() : txout.nValue is negative"));
         if (txout.nValue > MAX_MONEY)
             return DoS(100, error("CTransaction::CheckTransaction() : txout.nValue too high"));
         nValueOut += txout.nValue;
@@ -513,19 +531,58 @@ bool CTransaction::CheckTransaction() const
     return true;
 }
 
-int64 CTransaction::GetMinFee(unsigned int nBlockSize, bool fAllowFree,
-                              enum GetMinFee_mode mode) const
+int64 CTransaction::GetMinFee(unsigned int nBlockSize, bool fAllowFree, enum GetMinFee_mode mode, unsigned int nBytes) const
 {
-    // Base fee is either MIN_TX_FEE or MIN_RELAY_TX_FEE
-    int64 nBaseFee = (mode == GMF_RELAY) ? MIN_RELAY_TX_FEE : MIN_TX_FEE;
+    // Use new fees approach if we are on test network or 
+    //    switch date has been reached
+    bool fNewApproach = fTestNet || nTime > FEE_SWITCH_TIME;
+
+    int64 nMinTxFee = MIN_TX_FEE, nMinRelayTxFee = MIN_RELAY_TX_FEE;
+
+    if(!fNewApproach || IsCoinStake())
+    {
+        // Enforce 0.01 as minimum fee for old approach or coinstake
+        nMinTxFee = CENT;
+        nMinRelayTxFee = CENT;
+    }
+
+    // Base fee is either nMinTxFee or nMinRelayTxFee
+    int64 nBaseFee = (mode == GMF_RELAY) ? nMinRelayTxFee : nMinTxFee;
 
-    unsigned int nBytes = ::GetSerializeSize(*this, SER_NETWORK, PROTOCOL_VERSION);
     unsigned int nNewBlockSize = nBlockSize + nBytes;
     int64 nMinFee = (1 + (int64)nBytes / 1000) * nBaseFee;
 
-    // To limit dust spam, require MIN_TX_FEE/MIN_RELAY_TX_FEE if any output is less than 0.01
-    if (nMinFee < nBaseFee)
+    if (fNewApproach)
+    {
+        if (fAllowFree)
+        {
+            if (nBlockSize == 1)
+            {
+                // Transactions under 1K are free
+                if (nBytes < 1000)
+                    nMinFee = 0;
+            }
+            else
+            {
+                // Free transaction area
+                if (nNewBlockSize < 27000)
+                    nMinFee = 0;
+            }
+        }
+
+        // To limit dust spam, require additional MIN_TX_FEE/MIN_RELAY_TX_FEE for 
+        //    each non empty output which is less than 0.01
+        //
+        // It's safe to ignore empty outputs here, because these inputs are allowed
+        //     only for coinbase and coinstake transactions.
+        BOOST_FOREACH(const CTxOut& txout, vout)
+            if (txout.nValue < CENT && !txout.IsEmpty())
+                nMinFee += nBaseFee;
+    }
+    else if (nMinFee < nBaseFee)
     {
+        // To limit dust spam, require MIN_TX_FEE/MIN_RELAY_TX_FEE if 
+        //    any output is less than 0.01
         BOOST_FOREACH(const CTxOut& txout, vout)
             if (txout.nValue < CENT)
                 nMinFee = nBaseFee;
@@ -541,6 +598,7 @@ int64 CTransaction::GetMinFee(unsigned int nBlockSize, bool fAllowFree,
 
     if (!MoneyRange(nMinFee))
         nMinFee = MAX_MONEY;
+
     return nMinFee;
 }
 
@@ -635,7 +693,7 @@ bool CTxMemPool::accept(CTxDB& txdb, CTransaction &tx, bool fCheckInputs,
         unsigned int nSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
 
         // Don't accept it if it can't get into a block
-        int64 txMinFee = tx.GetMinFee(1000, false, GMF_RELAY);
+        int64 txMinFee = tx.GetMinFee(1000, true, GMF_RELAY, nSize);
         if (nFees < txMinFee)
             return error("CTxMemPool::accept() : not enough fees %s, %"PRI64d" < %"PRI64d,
                          hash.ToString().c_str(),
@@ -668,7 +726,7 @@ bool CTxMemPool::accept(CTxDB& txdb, CTransaction &tx, bool fCheckInputs,
 
         // Check against previous transactions
         // This is done last to help prevent CPU exhaustion denial-of-service attacks.
-        if (!tx.ConnectInputs(txdb, mapInputs, mapUnused, CDiskTxPos(1,1,1), pindexBest, false, false))
+        if (!tx.ConnectInputs(txdb, mapInputs, mapUnused, CDiskTxPos(1,1,1), pindexBest, false, false, true, SIG_SWITCH_TIME < tx.nTime ? STRICT_FLAGS : SOFT_FLAGS))
         {
             return error("CTxMemPool::accept() : ConnectInputs failed %s", hash.ToString().substr(0,10).c_str());
         }
@@ -954,7 +1012,7 @@ CBigNum inline GetProofOfStakeLimit(int nHeight, unsigned int nTime)
 }
 
 // miner's coin base reward based on nBits
-int64 GetProofOfWorkReward(unsigned int nBits)
+int64 GetProofOfWorkReward(unsigned int nBits, int64 nFees)
 {
     CBigNum bnSubsidyLimit = MAX_MINT_PROOF_OF_WORK;
 
@@ -989,7 +1047,7 @@ int64 GetProofOfWorkReward(unsigned int nBits)
     if (fDebug && GetBoolArg("-printcreation"))
         printf("GetProofOfWorkReward() : create=%s nBits=0x%08x nSubsidy=%"PRI64d"\n", FormatMoney(nSubsidy).c_str(), nBits, nSubsidy);
 
-    return min(nSubsidy, MAX_MINT_PROOF_OF_WORK);
+    return min(nSubsidy, MAX_MINT_PROOF_OF_WORK) + nFees;
 }
 
 // miner's coin stake reward based on nBits and coin age spent (coin-days)
@@ -1064,11 +1122,7 @@ int64 GetProofOfStakeReward(int64 nCoinAge, unsigned int nBits, unsigned int nTi
     if(bCoinYearOnly)
         return nRewardCoinYear;
 
-    // Fix problem with proof-of-stake rewards calculation since 20 Sep 2013
-    if(nTime < CHAINCHECKS_SWITCH_TIME)
-        nSubsidy = nCoinAge * 33 / (365 * 33 + 8) * nRewardCoinYear;
-    else
-        nSubsidy = nCoinAge * nRewardCoinYear * 33 / (365 * 33 + 8);
+    nSubsidy = nCoinAge * nRewardCoinYear * 33 / (365 * 33 + 8);
 
     // Set reasonable reward limit for large inputs since 20 Oct 2013
     //
@@ -1406,14 +1460,26 @@ unsigned int CTransaction::GetP2SHSigOpCount(const MapPrevTx& inputs) const
     return nSigOps;
 }
 
-bool CTransaction::ConnectInputs(CTxDB& txdb, MapPrevTx inputs,
-                                 map<uint256, CTxIndex>& mapTestPool, const CDiskTxPos& posThisTx,
-                                 const CBlockIndex* pindexBlock, bool fBlock, bool fMiner, bool fStrictPayToScriptHash)
+bool CScriptCheck::operator()() const {
+    const CScript &scriptSig = ptxTo->vin[nIn].scriptSig;
+    if (!VerifyScript(scriptSig, scriptPubKey, *ptxTo, nIn, nFlags, nHashType))
+        return error("CScriptCheck() : %s VerifySignature failed", ptxTo->GetHash().ToString().substr(0,10).c_str());
+    return true;
+}
+
+bool VerifySignature(const CTransaction& txFrom, const CTransaction& txTo, unsigned int nIn, unsigned int flags, int nHashType)
+{
+    return CScriptCheck(txFrom, txTo, nIn, flags, nHashType)();
+}
+
+bool CTransaction::ConnectInputs(CTxDB& txdb, MapPrevTx inputs, map<uint256, CTxIndex>& mapTestPool, const CDiskTxPos& posThisTx,
+    const CBlockIndex* pindexBlock, bool fBlock, bool fMiner, bool fScriptChecks, unsigned int flags, std::vector<CScriptCheck> *pvChecks)
 {
     // Take over previous transactions' spent pointers
     // fBlock is true when this is called from AcceptBlock when a new best-block is added to the blockchain
     // fMiner is true when called from the internal bitcoin miner
     // ... both are false when called from CTransaction::AcceptToMemoryPool
+
     if (!IsCoinBase())
     {
         int64 nValueIn = 0;
@@ -1444,6 +1510,10 @@ bool CTransaction::ConnectInputs(CTxDB& txdb, MapPrevTx inputs,
                 return DoS(100, error("ConnectInputs() : txin values out of range"));
 
         }
+
+        if (pvChecks)
+            pvChecks->reserve(vin.size());
+
         // The first loop above does all the inexpensive checks.
         // Only if ALL inputs pass do we perform expensive ECDSA signature checks.
         // Helps prevent CPU exhaustion attacks.
@@ -1463,16 +1533,24 @@ bool CTransaction::ConnectInputs(CTxDB& txdb, MapPrevTx inputs,
             // Skip ECDSA signature verification when connecting blocks (fBlock=true)
             // before the last blockchain checkpoint. This is safe because block merkle hashes are
             // still computed and checked, and any change will be caught at the next checkpoint.
-            if (!(fBlock && (nBestHeight < Checkpoints::GetTotalBlocksEstimate())))
+            if (fScriptChecks)
             {
                 // Verify signature
-                if (!VerifySignature(txPrev, *this, i, fStrictPayToScriptHash, 0))
+                CScriptCheck check(txPrev, *this, i, flags, 0);
+                if (pvChecks)
                 {
-                    // only during transition phase for P2SH: do not invoke anti-DoS code for
-                    // potentially old clients relaying bad P2SH transactions
-                    if (fStrictPayToScriptHash && VerifySignature(txPrev, *this, i, false, 0))
-                        return error("ConnectInputs() : %s P2SH VerifySignature failed", GetHash().ToString().substr(0,10).c_str());
-
+                    pvChecks->push_back(CScriptCheck());
+                    check.swap(pvChecks->back());
+                }
+                else if (!check())
+                {
+                    if (flags & STRICT_FLAGS)
+                    {
+                        // Don't trigger DoS code in case of STRICT_FLAGS caused failure.
+                        CScriptCheck check(txPrev, *this, i, flags & ~STRICT_FLAGS, 0);
+                        if (check())
+                            return error("ConnectInputs() : %s strict VerifySignature failed", GetHash().ToString().substr(0,10).c_str());
+                    }
                     return DoS(100,error("ConnectInputs() : %s VerifySignature failed", GetHash().ToString().substr(0,10).c_str()));
                 }
             }
@@ -1494,11 +1572,13 @@ bool CTransaction::ConnectInputs(CTxDB& txdb, MapPrevTx inputs,
             if (!GetCoinAge(txdb, nCoinAge))
                 return error("ConnectInputs() : %s unable to get coin age for coinstake", GetHash().ToString().substr(0,10).c_str());
 
-            int64 nStakeReward = GetValueOut() - nValueIn;
-            int64 nCalculatedStakeReward = GetProofOfStakeReward(nCoinAge, pindexBlock->nBits, nTime) - GetMinFee() + MIN_TX_FEE;
+            unsigned int nTxSize = (nTime > VALIDATION_SWITCH_TIME || fTestNet) ? GetSerializeSize(SER_NETWORK, PROTOCOL_VERSION) : 0;
+
+            int64 nReward = GetValueOut() - nValueIn;
+            int64 nCalculatedReward = GetProofOfStakeReward(nCoinAge, pindexBlock->nBits, nTime) - GetMinFee(1, false, GMF_BLOCK, nTxSize) + CENT;
 
-            if (nStakeReward > nCalculatedStakeReward)
-                return DoS(100, error("ConnectInputs() : coinstake pays too much(actual=%"PRI64d" vs calculated=%"PRI64d")", nStakeReward, nCalculatedStakeReward));
+            if (nReward > nCalculatedReward)
+                return DoS(100, error("ConnectInputs() : coinstake pays too much(actual=%"PRI64d" vs calculated=%"PRI64d")", nReward, nCalculatedReward));
         }
         else
         {
@@ -1509,9 +1589,6 @@ bool CTransaction::ConnectInputs(CTxDB& txdb, MapPrevTx inputs,
             int64 nTxFee = nValueIn - GetValueOut();
             if (nTxFee < 0)
                 return DoS(100, error("ConnectInputs() : %s nTxFee < 0", GetHash().ToString().substr(0,10).c_str()));
-            // ppcoin: enforce transaction fees for every block
-            if (nTxFee < GetMinFee())
-                return fBlock? DoS(100, error("ConnectInputs() : %s not paying required fee=%s, paid=%s", GetHash().ToString().substr(0,10).c_str(), FormatMoney(GetMinFee()).c_str(), FormatMoney(nTxFee).c_str())) : false;
 
             nFees += nTxFee;
             if (!MoneyRange(nFees))
@@ -1544,8 +1621,8 @@ bool CTransaction::ClientConnectInputs()
                 return false;
 
             // Verify signature
-            if (!VerifySignature(txPrev, *this, i, true, 0))
-                return error("ConnectInputs() : VerifySignature failed");
+            if (!VerifySignature(txPrev, *this, i, SCRIPT_VERIFY_NOCACHE | SCRIPT_VERIFY_P2SH, 0))
+                return error("ClientConnectInputs() : VerifySignature failed");
 
             ///// this is redundant with the mempool.mapNextTx stuff,
             ///// not sure which I want to get rid of
@@ -1596,12 +1673,27 @@ bool CBlock::DisconnectBlock(CTxDB& txdb, CBlockIndex* pindex)
     return true;
 }
 
+static CCheckQueue<CScriptCheck> scriptcheckqueue(128);
+
+void ThreadScriptCheck(void*) {
+    vnThreadsRunning[THREAD_SCRIPTCHECK]++;
+    RenameThread("novacoin-scriptch");
+    scriptcheckqueue.Thread();
+    vnThreadsRunning[THREAD_SCRIPTCHECK]--;
+}
+
+void ThreadScriptCheckQuit() {
+    scriptcheckqueue.Quit();
+}
+
 bool CBlock::ConnectBlock(CTxDB& txdb, CBlockIndex* pindex, bool fJustCheck)
 {
     // Check it again in case a previous version let a bad block in, but skip BlockSig checking
     if (!CheckBlock(!fJustCheck, !fJustCheck, false))
         return false;
 
+    bool fProtocol048 = fTestNet || VALIDATION_SWITCH_TIME < nTime;
+
     // Do not allow blocks that contain transactions which 'overwrite' older transactions,
     // unless those are already completely spent.
     // If such overwrites are allowed, coinbases and transactions depending upon those
@@ -1615,7 +1707,7 @@ bool CBlock::ConnectBlock(CTxDB& txdb, CBlockIndex* pindex, bool fJustCheck)
     // two in the chain that violate it. This prevents exploiting the issue against nodes in their
     // initial block download.
     bool fEnforceBIP30 = true; // Always active in NovaCoin
-    bool fStrictPayToScriptHash = true; // Always active in NovaCoin
+    bool fScriptChecks = pindex->nHeight >= Checkpoints::GetTotalBlocksEstimate();
 
     //// issue here: it doesn't know the version
     unsigned int nTxPos;
@@ -1627,6 +1719,8 @@ bool CBlock::ConnectBlock(CTxDB& txdb, CBlockIndex* pindex, bool fJustCheck)
         nTxPos = pindex->nBlockPos + ::GetSerializeSize(CBlock(), SER_DISK, CLIENT_VERSION) - (2 * GetSizeOfCompactSize(0)) + GetSizeOfCompactSize(vtx.size());
 
     map<uint256, CTxIndex> mapQueuedChanges;
+    CCheckQueueControl<CScriptCheck> control(fScriptChecks && nScriptCheckThreads ? &scriptcheckqueue : NULL);
+
     int64 nFees = 0;
     int64 nValueIn = 0;
     int64 nValueOut = 0;
@@ -1661,15 +1755,12 @@ bool CBlock::ConnectBlock(CTxDB& txdb, CBlockIndex* pindex, bool fJustCheck)
             if (!tx.FetchInputs(txdb, mapQueuedChanges, true, false, mapInputs, fInvalid))
                 return false;
 
-            if (fStrictPayToScriptHash)
-            {
-                // Add in sigops done by pay-to-script-hash inputs;
-                // this is to prevent a "rogue miner" from creating
-                // an incredibly-expensive-to-validate block.
-                nSigOps += tx.GetP2SHSigOpCount(mapInputs);
-                if (nSigOps > MAX_BLOCK_SIGOPS)
-                    return DoS(100, error("ConnectBlock() : too many sigops"));
-            }
+            // Add in sigops done by pay-to-script-hash inputs;
+            // this is to prevent a "rogue miner" from creating
+            // an incredibly-expensive-to-validate block.
+            nSigOps += tx.GetP2SHSigOpCount(mapInputs);
+            if (nSigOps > MAX_BLOCK_SIGOPS)
+                return DoS(100, error("ConnectBlock() : too many sigops"));
 
             int64 nTxValueIn = tx.GetValueIn(mapInputs);
             int64 nTxValueOut = tx.GetValueOut();
@@ -1678,22 +1769,38 @@ bool CBlock::ConnectBlock(CTxDB& txdb, CBlockIndex* pindex, bool fJustCheck)
             if (!tx.IsCoinStake())
                 nFees += nTxValueIn - nTxValueOut;
 
-            if (!tx.ConnectInputs(txdb, mapInputs, mapQueuedChanges, posThisTx, pindex, true, false, fStrictPayToScriptHash))
+            std::vector<CScriptCheck> vChecks;
+            if (!tx.ConnectInputs(txdb, mapInputs, mapQueuedChanges, posThisTx, pindex, true, false, fScriptChecks, SCRIPT_VERIFY_NOCACHE | SCRIPT_VERIFY_P2SH, nScriptCheckThreads ? &vChecks : NULL))
                 return false;
+            control.Add(vChecks);
         }
 
         mapQueuedChanges[hashTx] = CTxIndex(posThisTx, tx.vout.size());
     }
 
-    // ppcoin: track money supply and mint amount info
+    if (!control.Wait())
+        return DoS(100, false);
+
+    if (IsProofOfWork())
+    {
+        int64 nBlockReward = GetProofOfWorkReward(nBits, fProtocol048 ? nFees : 0);
+
+        // Check coinbase reward
+        if (vtx[0].GetValueOut() > nBlockReward)
+            return error("CheckBlock() : coinbase reward exceeded (actual=%"PRI64d" vs calculated=%"PRI64d")",
+                   vtx[0].GetValueOut(),
+                   nBlockReward);
+    }
+
+    // track money supply and mint amount info
     pindex->nMint = nValueOut - nValueIn + nFees;
     pindex->nMoneySupply = (pindex->pprev? pindex->pprev->nMoneySupply : 0) + nValueOut - nValueIn;
     if (!txdb.WriteBlockIndex(CDiskBlockIndex(pindex)))
         return error("Connect() : WriteBlockIndex for pindex failed");
 
-    // ppcoin: fees are not collected by miners as in bitcoin
-    // ppcoin: fees are destroyed to compensate the entire network
-    if (fDebug && GetBoolArg("-printcreation"))
+    // fees are not collected by proof-of-stake miners
+    // fees are destroyed to compensate the entire network
+    if (fProtocol048 && fDebug && IsProofOfStake() && GetBoolArg("-printcreation"))
         printf("ConnectBlock() : destroy=%s nFees=%"PRI64d"\n", FormatMoney(nFees).c_str(), nFees);
 
     if (fJustCheck)
@@ -2069,7 +2176,7 @@ bool CBlock::AddToBlockIndex(unsigned int nFile, unsigned int nBlockPos)
     // ppcoin: compute stake modifier
     uint64 nStakeModifier = 0;
     bool fGeneratedStakeModifier = false;
-    if (!ComputeNextStakeModifier(pindexNew->pprev, nStakeModifier, fGeneratedStakeModifier))
+    if (!ComputeNextStakeModifier(pindexNew, nStakeModifier, fGeneratedStakeModifier))
         return error("AddToBlockIndex() : ComputeNextStakeModifier() failed");
     pindexNew->SetStakeModifier(nStakeModifier, fGeneratedStakeModifier);
     pindexNew->nStakeModifierChecksum = GetStakeModifierChecksum(pindexNew);
@@ -2095,8 +2202,6 @@ bool CBlock::AddToBlockIndex(unsigned int nFile, unsigned int nBlockPos)
         if (!SetBestChain(txdb, pindexNew))
             return false;
 
-    txdb.Close();
-
     if (pindexNew == pindexBest)
     {
         // Notify UI to display prev block's coinbase if it was ours
@@ -2121,27 +2226,51 @@ bool CBlock::CheckBlock(bool fCheckPOW, bool fCheckMerkleRoot, bool fCheckSig) c
     if (vtx.empty() || vtx.size() > MAX_BLOCK_SIZE || ::GetSerializeSize(*this, SER_NETWORK, PROTOCOL_VERSION) > MAX_BLOCK_SIZE)
         return DoS(100, error("CheckBlock() : size limits failed"));
 
+    bool fProtocol048 = fTestNet || VALIDATION_SWITCH_TIME < nTime;
+
     // Check proof of work matches claimed amount
     if (fCheckPOW && IsProofOfWork() && !CheckProofOfWork(GetHash(), nBits))
         return DoS(50, error("CheckBlock() : proof of work failed"));
 
     // Check timestamp
-    if (GetBlockTime() > GetAdjustedTime() + nMaxClockDrift)
+    if (GetBlockTime() > FutureDrift(GetAdjustedTime()))
         return error("CheckBlock() : block timestamp too far in the future");
 
     // First transaction must be coinbase, the rest must not be
     if (vtx.empty() || !vtx[0].IsCoinBase())
         return DoS(100, error("CheckBlock() : first tx is not coinbase"));
+
+    if (!fProtocol048)
+    {
+        // Check coinbase timestamp
+        if (GetBlockTime() < (int64)vtx[0].nTime)
+            return DoS(100, error("CheckBlock() : coinbase timestamp violation"));
+    }
+    else
+    {
+        // Check coinbase timestamp
+        if (GetBlockTime() < PastDrift((int64)vtx[0].nTime))
+            return DoS(50, error("CheckBlock() : coinbase timestamp is too late"));
+    }
+
     for (unsigned int i = 1; i < vtx.size(); i++)
+    {
         if (vtx[i].IsCoinBase())
             return DoS(100, error("CheckBlock() : more than one coinbase"));
 
-    // Check coinbase timestamp
-    if (GetBlockTime() > (int64)vtx[0].nTime + nMaxClockDrift)
-        return DoS(50, error("CheckBlock() : coinbase timestamp is too early"));
+        // Check transaction timestamp
+        if (GetBlockTime() < (int64)vtx[i].nTime)
+            return DoS(50, error("CheckBlock() : block timestamp earlier than transaction timestamp"));
+    }
 
     if (IsProofOfStake())
     {
+        if (fProtocol048)
+        {
+            if (nNonce != 0)
+                return DoS(100, error("CheckBlock() : non-zero nonce in proof-of-stake block"));
+        }
+
         // Coinbase output should be empty if proof-of-stake block
         if (vtx[0].vout.size() != 1 || !vtx[0].vout[0].IsEmpty())
             return DoS(100, error("CheckBlock() : coinbase output not empty for proof-of-stake block"));
@@ -2154,7 +2283,7 @@ bool CBlock::CheckBlock(bool fCheckPOW, bool fCheckMerkleRoot, bool fCheckSig) c
                 return DoS(100, error("CheckBlock() : more than one coinstake"));
 
         // Check coinstake timestamp
-        if (!CheckCoinStakeTimestamp(GetBlockTime(), (int64)vtx[1].nTime))
+        if (GetBlockTime() != (int64)vtx[1].nTime)
             return DoS(50, error("CheckBlock() : coinstake timestamp violation nTimeBlock=%"PRI64d" nTimeTx=%u", GetBlockTime(), vtx[1].nTime));
 
         // NovaCoin: check proof-of-stake block signature
@@ -2163,15 +2292,6 @@ bool CBlock::CheckBlock(bool fCheckPOW, bool fCheckMerkleRoot, bool fCheckSig) c
     }
     else
     {
-        // Coinbase fee paid until 20 Sep 2013
-        int64 nFee = GetBlockTime() < CHAINCHECKS_SWITCH_TIME ? vtx[0].GetMinFee() - MIN_TX_FEE : 0;
-
-        // Check coinbase reward
-        if (vtx[0].GetValueOut() > (GetProofOfWorkReward(nBits) - nFee))
-            return DoS(50, error("CheckBlock() : coinbase reward exceeded (actual=%"PRI64d" vs calculated=%"PRI64d")",
-                   vtx[0].GetValueOut(),
-                   GetProofOfWorkReward(nBits) - nFee));
-
         // Should we check proof-of-work block signature or not?
         //
         // * Always skip on TestNet
@@ -2180,12 +2300,10 @@ bool CBlock::CheckBlock(bool fCheckPOW, bool fCheckMerkleRoot, bool fCheckSig) c
 
         if(!fTestNet && fCheckSig)
         {
-            bool isAfterCheckpoint = (GetBlockTime() > Checkpoints::GetLastCheckpointTime());
             bool checkEntropySig = (GetBlockTime() < ENTROPY_SWITCH_TIME);
-            bool checkPoWSig = (isAfterCheckpoint && GetBlockTime() < CHAINCHECKS_SWITCH_TIME);
 
             // NovaCoin: check proof-of-work block signature
-            if ((checkEntropySig || checkPoWSig) && !CheckBlockSignature(false))
+            if (checkEntropySig && !CheckBlockSignature(false))
                 return DoS(100, error("CheckBlock() : bad proof-of-work block signature"));
         }
     }
@@ -2195,10 +2313,6 @@ bool CBlock::CheckBlock(bool fCheckPOW, bool fCheckMerkleRoot, bool fCheckSig) c
     {
         if (!tx.CheckTransaction())
             return DoS(tx.nDoS, error("CheckBlock() : CheckTransaction failed"));
-
-        // ppcoin: check transaction timestamp
-        if (GetBlockTime() < (int64)tx.nTime)
-            return DoS(50, error("CheckBlock() : block timestamp earlier than transaction timestamp"));
     }
 
     // Check for duplicate txids. This is caught by ConnectInputs(),
@@ -2246,7 +2360,7 @@ bool CBlock::AcceptBlock()
         return DoS(100, error("AcceptBlock() : incorrect %s", IsProofOfWork() ? "proof-of-work" : "proof-of-stake"));
 
     // Check timestamp against prev
-    if (GetBlockTime() <= pindexPrev->GetMedianTimePast() || GetBlockTime() + nMaxClockDrift < pindexPrev->GetBlockTime())
+    if (GetBlockTime() <= pindexPrev->GetMedianTimePast() || FutureDrift(GetBlockTime()) < pindexPrev->GetBlockTime())
         return error("AcceptBlock() : block's timestamp is too early");
 
     // Check that all transactions are finalized
@@ -2258,13 +2372,19 @@ bool CBlock::AcceptBlock()
     if (!Checkpoints::CheckHardened(nHeight, hash))
         return DoS(100, error("AcceptBlock() : rejected by hardened checkpoint lock-in at %d", nHeight));
 
+    bool cpSatisfies = Checkpoints::CheckSync(hash, pindexPrev);
+
     // Check that the block satisfies synchronized checkpoint
-    if (!GetBoolArg("-nosynccheckpoints", false) && !Checkpoints::CheckSync(hash, pindexPrev))
+    if (CheckpointsMode == Checkpoints::STRICT && !cpSatisfies)
         return error("AcceptBlock() : rejected by synchronized checkpoint");
 
+    if (CheckpointsMode == Checkpoints::ADVISORY && !cpSatisfies)
+        strMiscWarning = _("WARNING: syncronized checkpoint violation detected, but skipped!");
+
     // Enforce rule that the coinbase starts with serialized block height
     CScript expect = CScript() << nHeight;
-    if (!std::equal(expect.begin(), expect.end(), vtx[0].vin[0].scriptSig.begin()))
+    if (vtx[0].vin[0].scriptSig.size() < expect.size() ||
+        !std::equal(expect.begin(), expect.end(), vtx[0].vin[0].scriptSig.begin()))
         return DoS(100, error("AcceptBlock() : block height mismatch in coinbase"));
 
     // Write block to history file
@@ -2301,7 +2421,7 @@ uint256 CBlockIndex::GetBlockTrust() const
     if (bnTarget <= 0)
         return 0;
 
-    /* Old protocol, will be removed later */
+    /* Old protocol */
     if (!fTestNet && GetBlockTime() < CHAINCHECKS_SWITCH_TIME)
         return (IsProofOfStake()? ((CBigNum(1)<<256) / (bnTarget+1)).getuint256() : 1);
 
@@ -2510,61 +2630,53 @@ bool ProcessBlock(CNode* pfrom, CBlock* pblock)
     return true;
 }
 
-// ppcoin: sign block
-bool CBlock::SignBlock(const CKeyStore& keystore)
+// novacoin: attempt to generate suitable proof-of-stake
+bool CBlock::SignBlock(CWallet& wallet)
 {
-    vector<valtype> vSolutions;
-    txnouttype whichType;
-
-    if(!IsProofOfStake())
-    {
-        for(unsigned int i = 0; i < vtx[0].vout.size(); i++)
-        {
-            const CTxOut& txout = vtx[0].vout[i];
+    // if we are trying to sign
+    //    something except proof-of-stake block template
+    if (!vtx[0].vout[0].IsEmpty())
+        return false;
 
-            if (!Solver(txout.scriptPubKey, whichType, vSolutions))
-                continue;
+    // if we are trying to sign
+    //    a complete proof-of-stake block
+    if (IsProofOfStake())
+        return true;
 
-            if (whichType == TX_PUBKEY)
-            {
-                // Sign
-                valtype& vchPubKey = vSolutions[0];
-                CKey key;
+    static int64 nLastCoinStakeSearchTime = GetAdjustedTime(); // startup timestamp
 
-                if (!keystore.GetKey(Hash160(vchPubKey), key))
-                    continue;
-                if (key.GetPubKey() != vchPubKey)
-                    continue;
-                if(!key.Sign(GetHash(), vchBlockSig))
-                    continue;
+    CKey key;
+    CTransaction txCoinStake;
+    int64 nSearchTime = txCoinStake.nTime; // search to current time
 
-                return true;
-            }
-        }
-    }
-    else
+    if (nSearchTime > nLastCoinStakeSearchTime)
     {
-        const CTxOut& txout = vtx[1].vout[1];
-
-        if (!Solver(txout.scriptPubKey, whichType, vSolutions))
-            return false;
-
-        if (whichType == TX_PUBKEY)
+        if (wallet.CreateCoinStake(wallet, nBits, nSearchTime-nLastCoinStakeSearchTime, txCoinStake, key))
         {
-            // Sign
-            valtype& vchPubKey = vSolutions[0];
-            CKey key;
-
-            if (!keystore.GetKey(Hash160(vchPubKey), key))
-                return false;
-            if (key.GetPubKey() != vchPubKey)
-                return false;
-
-            return key.Sign(GetHash(), vchBlockSig);
+            if (txCoinStake.nTime >= max(pindexBest->GetMedianTimePast()+1, PastDrift(pindexBest->GetBlockTime())))
+            {
+                // make sure coinstake would meet timestamp protocol
+                //    as it would be the same as the block timestamp
+                vtx[0].nTime = nTime = txCoinStake.nTime;
+                nTime = max(pindexBest->GetMedianTimePast()+1, GetMaxTransactionTime());
+                nTime = max(GetBlockTime(), PastDrift(pindexBest->GetBlockTime()));
+
+                // we have to make sure that we have no future timestamps in
+                //    our transactions set
+                for (vector<CTransaction>::iterator it = vtx.begin(); it != vtx.end();)
+                    if (it->nTime > nTime) { it = vtx.erase(it); } else { ++it; }
+
+                vtx.insert(vtx.begin() + 1, txCoinStake);
+                hashMerkleRoot = BuildMerkleTree();
+
+                // append a signature to our block
+                return key.Sign(GetHash(), vchBlockSig);
+            }
         }
+        nLastCoinStakeSearchInterval = nSearchTime - nLastCoinStakeSearchTime;
+        nLastCoinStakeSearchTime = nSearchTime;
     }
 
-    printf("Sign failed\n");
     return false;
 }
 
@@ -2669,7 +2781,7 @@ static unsigned int nCurrentBlockFile = 1;
 FILE* AppendBlockFile(unsigned int& nFileRet)
 {
     nFileRet = 0;
-    loop
+    while (true)
     {
         FILE* file = OpenBlockFile(nCurrentBlockFile, 0, "ab");
         if (!file)
@@ -2689,6 +2801,8 @@ FILE* AppendBlockFile(unsigned int& nFileRet)
 
 bool LoadBlockIndex(bool fAllowNew)
 {
+    CBigNum bnTrustedModulus;
+
     if (fTestNet)
     {
         pchMessageStart[0] = 0xcd;
@@ -2696,20 +2810,27 @@ bool LoadBlockIndex(bool fAllowNew)
         pchMessageStart[2] = 0xc0;
         pchMessageStart[3] = 0xef;
 
+        bnTrustedModulus.SetHex("f0d14cf72623dacfe738d0892b599be0f31052239cddd95a3f25101c801dc990453b38c9434efe3f372db39a32c2bb44cbaea72d62c8931fa785b0ec44531308df3e46069be5573e49bb29f4d479bfc3d162f57a5965db03810be7636da265bfced9c01a6b0296c77910ebdc8016f70174f0f18a57b3b971ac43a934c6aedbc5c866764a3622b5b7e3f9832b8b3f133c849dbcc0396588abcd1e41048555746e4823fb8aba5b3d23692c6857fccce733d6bb6ec1d5ea0afafecea14a0f6f798b6b27f77dc989c557795cc39a0940ef6bb29a7fc84135193a55bcfc2f01dd73efad1b69f45a55198bd0e6bef4d338e452f6a420f1ae2b1167b923f76633ab6e55");
         bnProofOfWorkLimit = bnProofOfWorkLimitTestNet; // 16 bits PoW target limit for testnet
         nStakeMinAge = 2 * 60 * 60; // test net min age is 2 hours
         nModifierInterval = 20 * 60; // test modifier interval is 20 minutes
         nCoinbaseMaturity = 10; // test maturity is 10 blocks
         nStakeTargetSpacing = 5 * 60; // test block spacing is 5 minutes
     }
+    else
+    {
+        bnTrustedModulus.SetHex("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");
+    }
+
+    // Set up the Zerocoin Params object
+    ZCParams = new libzerocoin::Params(bnTrustedModulus);
 
     //
     // Load block index
     //
-    CTxDB txdb("cr");
+    CTxDB txdb("cr+");
     if (!txdb.LoadBlockIndex())
         return false;
-    txdb.Close();
 
     //
     // Init with genesis block
@@ -2767,14 +2888,20 @@ bool LoadBlockIndex(bool fAllowNew)
         if (!block.AddToBlockIndex(nFile, nBlockPos))
             return error("LoadBlockIndex() : genesis block not accepted");
 
-        // ppcoin: initialize synchronized checkpoint
+        // initialize synchronized checkpoint
         if (!Checkpoints::WriteSyncCheckpoint((!fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet)))
             return error("LoadBlockIndex() : failed to init sync checkpoint");
+
+        // upgrade time set to zero if txdb initialized
+        {
+            if (!txdb.WriteModifierUpgradeTime(0))
+                return error("LoadBlockIndex() : failed to init upgrade info");
+            printf(" Upgrade Info: ModifierUpgradeTime txdb initialization\n");
+        }
     }
 
-    // ppcoin: if checkpoint master key changed must reset sync-checkpoint
     {
-        CTxDB txdb;
+        CTxDB txdb("r+");
         string strPubKey = "";
         if (!txdb.ReadCheckpointPubKey(strPubKey) || strPubKey != CSyncCheckpoint::strMasterPubKey)
         {
@@ -2787,7 +2914,26 @@ bool LoadBlockIndex(bool fAllowNew)
             if ((!fTestNet) && !Checkpoints::ResetSyncCheckpoint())
                 return error("LoadBlockIndex() : failed to reset sync-checkpoint");
         }
+
+        // upgrade time set to zero if blocktreedb initialized
+        if (txdb.ReadModifierUpgradeTime(nModifierUpgradeTime))
+        {
+            if (nModifierUpgradeTime)
+                printf(" Upgrade Info: blocktreedb upgrade detected at timestamp %d\n", nModifierUpgradeTime);
+            else
+                printf(" Upgrade Info: no blocktreedb upgrade detected.\n");
+        }
+        else
+        {
+            nModifierUpgradeTime = GetTime();
+            printf(" Upgrade Info: upgrading blocktreedb at timestamp %u\n", nModifierUpgradeTime);
+            if (!txdb.WriteModifierUpgradeTime(nModifierUpgradeTime))
+                return error("LoadBlockIndex() : failed to write upgrade info");
+        }
+
+#ifndef USE_LEVELDB
         txdb.Close();
+#endif
     }
 
     return true;
@@ -2929,14 +3075,6 @@ bool LoadExternalBlockFile(FILE* fileIn)
     return nLoaded > 0;
 }
 
-
-
-
-
-
-
-
-
 //////////////////////////////////////////////////////////////////////////////
 //
 // CAlert
@@ -2945,9 +3083,6 @@ bool LoadExternalBlockFile(FILE* fileIn)
 extern map<uint256, CAlert> mapAlerts;
 extern CCriticalSection cs_mapAlerts;
 
-static string strMintMessage = "Info: Minting suspended due to locked wallet.";
-static string strMintWarning;
-
 string GetWarnings(string strFor)
 {
     int nPriority = 0;
@@ -2957,13 +3092,6 @@ string GetWarnings(string strFor)
     if (GetBoolArg("-testsafemode"))
         strRPC = "test";
 
-    // ppcoin: wallet lock warning for minting
-    if (strMintWarning != "")
-    {
-        nPriority = 0;
-        strStatusBar = strMintWarning;
-    }
-
     // Misc warnings like out of disk space and clock is wrong
     if (strMiscWarning != "")
     {
@@ -2971,20 +3099,19 @@ string GetWarnings(string strFor)
         strStatusBar = strMiscWarning;
     }
 
-    // * Should not enter safe mode for longer invalid chain
-    // * If sync-checkpoint is too old do not enter safe mode
-    // * Do not display warning if -nosynccheckpoints specified
-    if (!GetBoolArg("-nosynccheckpoints", false) && Checkpoints::IsSyncCheckpointTooOld(60 * 60 * 24 * 10) && !fTestNet && !IsInitialBlockDownload())
+    // if detected unmet upgrade requirement enter safe mode
+    // Note: Modifier upgrade requires blockchain redownload if past protocol switch
+    if (IsFixedModifierInterval(nModifierUpgradeTime + 60*60*24)) // 1 day margin
     {
-        nPriority = 100;
-        strStatusBar = "WARNING: Checkpoint is too old. Wait for block chain to download, or notify developers.";
+        nPriority = 5000;
+        strStatusBar = strRPC = "WARNING: Blockchain redownload required approaching or past v.0.4.4.6u4 upgrade deadline.";
     }
 
-    // ppcoin: if detected invalid checkpoint enter safe mode
+    // if detected invalid checkpoint enter safe mode
     if (Checkpoints::hashInvalidCheckpoint != 0)
     {
         nPriority = 3000;
-        strStatusBar = strRPC = "WARNING: Invalid checkpoint found! Displayed transactions may not be correct! You may need to upgrade, or notify developers.";
+        strStatusBar = strRPC = _("WARNING: Invalid checkpoint found! Displayed transactions may not be correct! You may need to upgrade, or notify developers.");
     }
 
     // Alerts
@@ -3068,10 +3195,6 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         return true;
     }
 
-
-
-
-
     if (strCommand == "version")
     {
         // Each connection can only send one version message
@@ -3118,7 +3241,14 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
             return true;
         }
 
-        // ppcoin: record my external IP reported by peer
+        if (pfrom->nVersion < 60010)
+        {
+            printf("partner %s using a buggy client %d, disconnecting\n", pfrom->addr.ToString().c_str(), pfrom->nVersion);
+            pfrom->fDisconnect = true;
+            return true;
+        }
+
+        // record my external IP reported by peer
         if (addrFrom.IsRoutable() && addrMe.IsRoutable())
             addrSeenByPeer = addrMe;
 
@@ -3178,7 +3308,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
                 item.second.RelayTo(pfrom);
         }
 
-        // ppcoin: relay sync-checkpoint
+        // Relay sync-checkpoint
         {
             LOCK(Checkpoints::cs_hashSyncCheckpoint);
             if (!Checkpoints::checkpointMessage.IsNull())
@@ -3277,7 +3407,6 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
             pfrom->fDisconnect = true;
     }
 
-
     else if (strCommand == "inv")
     {
         vector<CInv> vInv;
@@ -3500,17 +3629,11 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         CInv inv(MSG_TX, tx.GetHash());
         pfrom->AddInventoryKnown(inv);
 
-        // Truncate messages to the size of the tx in them
-        unsigned int nSize = ::GetSerializeSize(tx,SER_NETWORK, PROTOCOL_VERSION);
-        if (nSize < vMsg.size()){
-            vMsg.resize(nSize);
-        }
-
         bool fMissingInputs = false;
         if (tx.AcceptToMemoryPool(txdb, true, &fMissingInputs))
         {
             SyncWithWallets(tx, NULL, true);
-            RelayMessage(inv, vMsg);
+            RelayTransaction(tx, inv.hash);
             mapAlreadyAskedFor.erase(inv);
             vWorkQueue.push_back(inv.hash);
             vEraseQueue.push_back(inv.hash);
@@ -3519,30 +3642,28 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
             for (unsigned int i = 0; i < vWorkQueue.size(); i++)
             {
                 uint256 hashPrev = vWorkQueue[i];
-                for (map<uint256, CDataStream*>::iterator mi = mapOrphanTransactionsByPrev[hashPrev].begin();
+                for (set<uint256>::iterator mi = mapOrphanTransactionsByPrev[hashPrev].begin();
                      mi != mapOrphanTransactionsByPrev[hashPrev].end();
                      ++mi)
                 {
-                    const CDataStream& vMsg = *((*mi).second);
-                    CTransaction tx;
-                    CDataStream(vMsg) >> tx;
-                    CInv inv(MSG_TX, tx.GetHash());
+                    const uint256& orphanTxHash = *mi;
+                    CTransaction& orphanTx = mapOrphanTransactions[orphanTxHash];
                     bool fMissingInputs2 = false;
 
-                    if (tx.AcceptToMemoryPool(txdb, true, &fMissingInputs2))
+                    if (orphanTx.AcceptToMemoryPool(txdb, true, &fMissingInputs2))
                     {
-                        printf("   accepted orphan tx %s\n", inv.hash.ToString().substr(0,10).c_str());
+                        printf("   accepted orphan tx %s\n", orphanTxHash.ToString().substr(0,10).c_str());
                         SyncWithWallets(tx, NULL, true);
-                        RelayMessage(inv, vMsg);
-                        mapAlreadyAskedFor.erase(inv);
-                        vWorkQueue.push_back(inv.hash);
-                        vEraseQueue.push_back(inv.hash);
+                        RelayTransaction(orphanTx, orphanTxHash);
+                        mapAlreadyAskedFor.erase(CInv(MSG_TX, orphanTxHash));
+                        vWorkQueue.push_back(orphanTxHash);
+                        vEraseQueue.push_back(orphanTxHash);
                     }
                     else if (!fMissingInputs2)
                     {
                         // invalid orphan
-                        vEraseQueue.push_back(inv.hash);
-                        printf("   removed invalid orphan tx %s\n", inv.hash.ToString().substr(0,10).c_str());
+                        vEraseQueue.push_back(orphanTxHash);
+                        printf("   removed invalid orphan tx %s\n", orphanTxHash.ToString().substr(0,10).c_str());
                     }
                 }
             }
@@ -3552,7 +3673,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         }
         else if (fMissingInputs)
         {
-            AddOrphanTx(vMsg);
+            AddOrphanTx(tx);
 
             // DoS prevention: do not allow mapOrphanTransactions to grow unbounded
             unsigned int nEvicted = LimitOrphanTxSize(MAX_ORPHAN_TRANSACTIONS);
@@ -3567,11 +3688,12 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
     {
         CBlock block;
         vRecv >> block;
+        uint256 hashBlock = block.GetHash();
 
-        printf("received block %s\n", block.GetHash().ToString().substr(0,20).c_str());
+        printf("received block %s\n", hashBlock.ToString().substr(0,20).c_str());
         // block.print();
 
-        CInv inv(MSG_BLOCK, block.GetHash());
+        CInv inv(MSG_BLOCK, hashBlock);
         pfrom->AddInventoryKnown(inv);
 
         if (ProcessBlock(pfrom, &block))
@@ -3740,7 +3862,7 @@ bool ProcessMessages(CNode* pfrom)
     //  (x) data
     //
 
-    loop
+    while (true)
     {
         // Don't bother if send buffer is too full to respond anyway
         if (pfrom->vSend.size() >= SendBufferSize())
@@ -3863,6 +3985,12 @@ bool SendMessages(CNode* pto, bool fSendTrickle)
                 pto->PushMessage("ping");
         }
 
+        // Start block sync
+        if (pto->fStartSync) {
+            pto->fStartSync = false;
+            pto->PushGetBlocks(pindexBest, uint256(0));
+        }
+
         // Resend wallet transactions that haven't gotten in a block yet
         ResendWalletTransactions();
 
@@ -4004,596 +4132,3 @@ bool SendMessages(CNode* pto, bool fSendTrickle)
     }
     return true;
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-//////////////////////////////////////////////////////////////////////////////
-//
-// BitcoinMiner
-//
-
-int static FormatHashBlocks(void* pbuffer, unsigned int len)
-{
-    unsigned char* pdata = (unsigned char*)pbuffer;
-    unsigned int blocks = 1 + ((len + 8) / 64);
-    unsigned char* pend = pdata + 64 * blocks;
-    memset(pdata + len, 0, 64 * blocks - len);
-    pdata[len] = 0x80;
-    unsigned int bits = len * 8;
-    pend[-1] = (bits >> 0) & 0xff;
-    pend[-2] = (bits >> 8) & 0xff;
-    pend[-3] = (bits >> 16) & 0xff;
-    pend[-4] = (bits >> 24) & 0xff;
-    return blocks;
-}
-
-static const unsigned int pSHA256InitState[8] =
-{0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19};
-
-void SHA256Transform(void* pstate, void* pinput, const void* pinit)
-{
-    SHA256_CTX ctx;
-    unsigned char data[64];
-
-    SHA256_Init(&ctx);
-
-    for (int i = 0; i < 16; i++)
-        ((uint32_t*)data)[i] = ByteReverse(((uint32_t*)pinput)[i]);
-
-    for (int i = 0; i < 8; i++)
-        ctx.h[i] = ((uint32_t*)pinit)[i];
-
-    SHA256_Update(&ctx, data, sizeof(data));
-    for (int i = 0; i < 8; i++)
-        ((uint32_t*)pstate)[i] = ctx.h[i];
-}
-
-// Some explaining would be appreciated
-class COrphan
-{
-public:
-    CTransaction* ptx;
-    set<uint256> setDependsOn;
-    double dPriority;
-    double dFeePerKb;
-
-    COrphan(CTransaction* ptxIn)
-    {
-        ptx = ptxIn;
-        dPriority = dFeePerKb = 0;
-    }
-
-    void print() const
-    {
-        printf("COrphan(hash=%s, dPriority=%.1f, dFeePerKb=%.1f)\n",
-               ptx->GetHash().ToString().substr(0,10).c_str(), dPriority, dFeePerKb);
-        BOOST_FOREACH(uint256 hash, setDependsOn)
-            printf("   setDependsOn %s\n", hash.ToString().substr(0,10).c_str());
-    }
-};
-
-
-uint64 nLastBlockTx = 0;
-uint64 nLastBlockSize = 0;
-int64 nLastCoinStakeSearchInterval = 0;
-// We want to sort transactions by priority and fee, so:
-typedef boost::tuple<double, double, CTransaction*> TxPriority;
-class TxPriorityCompare
-{
-    bool byFee;
-public:
-    TxPriorityCompare(bool _byFee) : byFee(_byFee) { }
-    bool operator()(const TxPriority& a, const TxPriority& b)
-    {
-        if (byFee)
-        {
-            if (a.get<1>() == b.get<1>())
-                return a.get<0>() < b.get<0>();
-            return a.get<1>() < b.get<1>();
-        }
-        else
-        {
-            if (a.get<0>() == b.get<0>())
-                return a.get<1>() < b.get<1>();
-            return a.get<0>() < b.get<0>();
-        }
-    }
-};
-
-// CreateNewBlock:
-//   fProofOfStake: try (best effort) to make a proof-of-stake block
-CBlock* CreateNewBlock(CWallet* pwallet, bool fProofOfStake)
-{
-    // Create new block
-    auto_ptr<CBlock> pblock(new CBlock());
-    if (!pblock.get())
-        return NULL;
-
-    // Create coinbase tx
-    CTransaction txNew;
-    txNew.vin.resize(1);
-    txNew.vin[0].prevout.SetNull();
-    txNew.vout.resize(1);
-
-    if (!fProofOfStake)
-    {
-        CReserveKey reservekey(pwallet);
-        txNew.vout[0].scriptPubKey << reservekey.GetReservedKey() << OP_CHECKSIG;
-    }
-    else
-        txNew.vout[0].SetEmpty();
-
-    // Add our coinbase tx as first transaction
-    pblock->vtx.push_back(txNew);
-
-    // Largest block you're willing to create:
-    unsigned int nBlockMaxSize = GetArg("-blockmaxsize", MAX_BLOCK_SIZE_GEN/2);
-    // Limit to betweeen 1K and MAX_BLOCK_SIZE-1K for sanity:
-    nBlockMaxSize = std::max((unsigned int)1000, std::min((unsigned int)(MAX_BLOCK_SIZE-1000), nBlockMaxSize));
-
-    // How much of the block should be dedicated to high-priority transactions,
-    // included regardless of the fees they pay
-    unsigned int nBlockPrioritySize = GetArg("-blockprioritysize", 27000);
-    nBlockPrioritySize = std::min(nBlockMaxSize, nBlockPrioritySize);
-
-    // Minimum block size you want to create; block will be filled with free transactions
-    // until there are no more or the block reaches this size:
-    unsigned int nBlockMinSize = GetArg("-blockminsize", 0);
-    nBlockMinSize = std::min(nBlockMaxSize, nBlockMinSize);
-
-    // Fee-per-kilobyte amount considered the same as "free"
-    // Be careful setting this: if you set it to zero then
-    // a transaction spammer can cheaply fill blocks using
-    // 1-satoshi-fee transactions. It should be set above the real
-    // cost to you of processing a transaction.
-    int64 nMinTxFee = MIN_TX_FEE;
-    if (mapArgs.count("-mintxfee"))
-        ParseMoney(mapArgs["-mintxfee"], nMinTxFee);
-
-    // ppcoin: if coinstake available add coinstake tx
-    static int64 nLastCoinStakeSearchTime = GetAdjustedTime();  // only initialized at startup
-    CBlockIndex* pindexPrev = pindexBest;
-
-    if (fProofOfStake)  // attempt to find a coinstake
-    {
-        pblock->nBits = GetNextTargetRequired(pindexPrev, true);
-        CTransaction txCoinStake;
-        int64 nSearchTime = txCoinStake.nTime; // search to current time
-        if (nSearchTime > nLastCoinStakeSearchTime)
-        {
-            if (pwallet->CreateCoinStake(*pwallet, pblock->nBits, nSearchTime-nLastCoinStakeSearchTime, txCoinStake))
-            {
-                if (txCoinStake.nTime >= max(pindexPrev->GetMedianTimePast()+1, pindexPrev->GetBlockTime() - nMaxClockDrift))
-                {   // make sure coinstake would meet timestamp protocol
-                    // as it would be the same as the block timestamp
-                    pblock->vtx[0].nTime = txCoinStake.nTime;
-                    pblock->vtx.push_back(txCoinStake);
-                }
-            }
-            nLastCoinStakeSearchInterval = nSearchTime - nLastCoinStakeSearchTime;
-            nLastCoinStakeSearchTime = nSearchTime;
-        }
-    }
-
-    pblock->nBits = GetNextTargetRequired(pindexPrev, pblock->IsProofOfStake());
-
-    // Collect memory pool transactions into the block
-    int64 nFees = 0;
-    {
-        LOCK2(cs_main, mempool.cs);
-        CBlockIndex* pindexPrev = pindexBest;
-        CTxDB txdb("r");
-
-        // Priority order to process transactions
-        list<COrphan> vOrphan; // list memory doesn't move
-        map<uint256, vector<COrphan*> > mapDependers;
-
-        // This vector will be sorted into a priority queue:
-        vector<TxPriority> vecPriority;
-        vecPriority.reserve(mempool.mapTx.size());
-        for (map<uint256, CTransaction>::iterator mi = mempool.mapTx.begin(); mi != mempool.mapTx.end(); ++mi)
-        {
-            CTransaction& tx = (*mi).second;
-            if (tx.IsCoinBase() || tx.IsCoinStake() || !tx.IsFinal())
-                continue;
-
-            COrphan* porphan = NULL;
-            double dPriority = 0;
-            int64 nTotalIn = 0;
-            bool fMissingInputs = false;
-            BOOST_FOREACH(const CTxIn& txin, tx.vin)
-            {
-                // Read prev transaction
-                CTransaction txPrev;
-                CTxIndex txindex;
-                if (!txPrev.ReadFromDisk(txdb, txin.prevout, txindex))
-                {
-                    // This should never happen; all transactions in the memory
-                    // pool should connect to either transactions in the chain
-                    // or other transactions in the memory pool.
-                    if (!mempool.mapTx.count(txin.prevout.hash))
-                    {
-                        printf("ERROR: mempool transaction missing input\n");
-                        if (fDebug) assert("mempool transaction missing input" == 0);
-                        fMissingInputs = true;
-                        if (porphan)
-                            vOrphan.pop_back();
-                        break;
-                    }
-
-                    // Has to wait for dependencies
-                    if (!porphan)
-                    {
-                        // Use list for automatic deletion
-                        vOrphan.push_back(COrphan(&tx));
-                        porphan = &vOrphan.back();
-                    }
-                    mapDependers[txin.prevout.hash].push_back(porphan);
-                    porphan->setDependsOn.insert(txin.prevout.hash);
-                    nTotalIn += mempool.mapTx[txin.prevout.hash].vout[txin.prevout.n].nValue;
-                    continue;
-                }
-                int64 nValueIn = txPrev.vout[txin.prevout.n].nValue;
-                nTotalIn += nValueIn;
-
-                int nConf = txindex.GetDepthInMainChain();
-                dPriority += (double)nValueIn * nConf;
-            }
-            if (fMissingInputs) continue;
-
-            // Priority is sum(valuein * age) / txsize
-            unsigned int nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
-            dPriority /= nTxSize;
-
-            // This is a more accurate fee-per-kilobyte than is used by the client code, because the
-            // client code rounds up the size to the nearest 1K. That's good, because it gives an
-            // incentive to create smaller transactions.
-            double dFeePerKb =  double(nTotalIn-tx.GetValueOut()) / (double(nTxSize)/1000.0);
-
-            if (porphan)
-            {
-                porphan->dPriority = dPriority;
-                porphan->dFeePerKb = dFeePerKb;
-            }
-            else
-                vecPriority.push_back(TxPriority(dPriority, dFeePerKb, &(*mi).second));
-        }
-
-        // Collect transactions into block
-        map<uint256, CTxIndex> mapTestPool;
-        uint64 nBlockSize = 1000;
-        uint64 nBlockTx = 0;
-        int nBlockSigOps = 100;
-        bool fSortedByFee = (nBlockPrioritySize <= 0);
-
-        TxPriorityCompare comparer(fSortedByFee);
-        std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
-
-        while (!vecPriority.empty())
-        {
-            // Take highest priority transaction off the priority queue:
-            double dPriority = vecPriority.front().get<0>();
-            double dFeePerKb = vecPriority.front().get<1>();
-            CTransaction& tx = *(vecPriority.front().get<2>());
-
-            std::pop_heap(vecPriority.begin(), vecPriority.end(), comparer);
-            vecPriority.pop_back();
-
-            // Size limits
-            unsigned int nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
-            if (nBlockSize + nTxSize >= nBlockMaxSize)
-                continue;
-
-            // Legacy limits on sigOps:
-            unsigned int nTxSigOps = tx.GetLegacySigOpCount();
-            if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS)
-                continue;
-
-            // Timestamp limit
-            if (tx.nTime > GetAdjustedTime() || (pblock->IsProofOfStake() && tx.nTime > pblock->vtx[1].nTime))
-                continue;
-
-            // ppcoin: simplify transaction fee - allow free = false
-            int64 nMinFee = tx.GetMinFee(nBlockSize, false, GMF_BLOCK);
-
-            // Skip free transactions if we're past the minimum block size:
-            if (fSortedByFee && (dFeePerKb < nMinTxFee) && (nBlockSize + nTxSize >= nBlockMinSize))
-                continue;
-
-            // Prioritize by fee once past the priority size or we run out of high-priority
-            // transactions:
-            if (!fSortedByFee &&
-                ((nBlockSize + nTxSize >= nBlockPrioritySize) || (dPriority < COIN * 144 / 250)))
-            {
-                fSortedByFee = true;
-                comparer = TxPriorityCompare(fSortedByFee);
-                std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
-            }
-
-            // Connecting shouldn't fail due to dependency on other memory pool transactions
-            // because we're already processing them in order of dependency
-            map<uint256, CTxIndex> mapTestPoolTmp(mapTestPool);
-            MapPrevTx mapInputs;
-            bool fInvalid;
-            if (!tx.FetchInputs(txdb, mapTestPoolTmp, false, true, mapInputs, fInvalid))
-                continue;
-
-            int64 nTxFees = tx.GetValueIn(mapInputs)-tx.GetValueOut();
-            if (nTxFees < nMinFee)
-                continue;
-
-            nTxSigOps += tx.GetP2SHSigOpCount(mapInputs);
-            if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS)
-                continue;
-
-            if (!tx.ConnectInputs(txdb, mapInputs, mapTestPoolTmp, CDiskTxPos(1,1,1), pindexPrev, false, true))
-                continue;
-            mapTestPoolTmp[tx.GetHash()] = CTxIndex(CDiskTxPos(1,1,1), tx.vout.size());
-            swap(mapTestPool, mapTestPoolTmp);
-
-            // Added
-            pblock->vtx.push_back(tx);
-            nBlockSize += nTxSize;
-            ++nBlockTx;
-            nBlockSigOps += nTxSigOps;
-            nFees += nTxFees;
-
-            if (fDebug && GetBoolArg("-printpriority"))
-            {
-                printf("priority %.1f feeperkb %.1f txid %s\n",
-                       dPriority, dFeePerKb, tx.GetHash().ToString().c_str());
-            }
-
-            // Add transactions that depend on this one to the priority queue
-            uint256 hash = tx.GetHash();
-            if (mapDependers.count(hash))
-            {
-                BOOST_FOREACH(COrphan* porphan, mapDependers[hash])
-                {
-                    if (!porphan->setDependsOn.empty())
-                    {
-                        porphan->setDependsOn.erase(hash);
-                        if (porphan->setDependsOn.empty())
-                        {
-                            vecPriority.push_back(TxPriority(porphan->dPriority, porphan->dFeePerKb, porphan->ptx));
-                            std::push_heap(vecPriority.begin(), vecPriority.end(), comparer);
-                        }
-                    }
-                }
-            }
-        }
-
-        nLastBlockTx = nBlockTx;
-        nLastBlockSize = nBlockSize;
-
-        if (fDebug && GetBoolArg("-printpriority"))
-            printf("CreateNewBlock(): total size %"PRI64u"\n", nBlockSize);
-
-        if (pblock->IsProofOfWork())
-            pblock->vtx[0].vout[0].nValue = GetProofOfWorkReward(pblock->nBits);
-
-        // Fill in header
-        pblock->hashPrevBlock  = pindexPrev->GetBlockHash();
-        if (pblock->IsProofOfStake())
-            pblock->nTime      = pblock->vtx[1].nTime; //same as coinstake timestamp
-        pblock->nTime          = max(pindexPrev->GetMedianTimePast()+1, pblock->GetMaxTransactionTime());
-        pblock->nTime          = max(pblock->GetBlockTime(), pindexPrev->GetBlockTime() - nMaxClockDrift);
-        if (pblock->IsProofOfWork())
-            pblock->UpdateTime(pindexPrev);
-        pblock->nNonce         = 0;
-    }
-
-    return pblock.release();
-}
-
-
-void IncrementExtraNonce(CBlock* pblock, CBlockIndex* pindexPrev, unsigned int& nExtraNonce)
-{
-    // Update nExtraNonce
-    static uint256 hashPrevBlock;
-    if (hashPrevBlock != pblock->hashPrevBlock)
-    {
-        nExtraNonce = 0;
-        hashPrevBlock = pblock->hashPrevBlock;
-    }
-    ++nExtraNonce;
-    unsigned int nHeight = pindexPrev->nHeight+1; // Height first in coinbase required for block.version=2
-    pblock->vtx[0].vin[0].scriptSig = (CScript() << nHeight << CBigNum(nExtraNonce)) + COINBASE_FLAGS;
-    assert(pblock->vtx[0].vin[0].scriptSig.size() <= 100);
-
-    pblock->hashMerkleRoot = pblock->BuildMerkleTree();
-}
-
-
-void FormatHashBuffers(CBlock* pblock, char* pmidstate, char* pdata, char* phash1)
-{
-    //
-    // Pre-build hash buffers
-    //
-    struct
-    {
-        struct unnamed2
-        {
-            int nVersion;
-            uint256 hashPrevBlock;
-            uint256 hashMerkleRoot;
-            unsigned int nTime;
-            unsigned int nBits;
-            unsigned int nNonce;
-        }
-        block;
-        unsigned char pchPadding0[64];
-        uint256 hash1;
-        unsigned char pchPadding1[64];
-    }
-    tmp;
-    memset(&tmp, 0, sizeof(tmp));
-
-    tmp.block.nVersion       = pblock->nVersion;
-    tmp.block.hashPrevBlock  = pblock->hashPrevBlock;
-    tmp.block.hashMerkleRoot = pblock->hashMerkleRoot;
-    tmp.block.nTime          = pblock->nTime;
-    tmp.block.nBits          = pblock->nBits;
-    tmp.block.nNonce         = pblock->nNonce;
-
-    FormatHashBlocks(&tmp.block, sizeof(tmp.block));
-    FormatHashBlocks(&tmp.hash1, sizeof(tmp.hash1));
-
-    // Byte swap all the input buffer
-    for (unsigned int i = 0; i < sizeof(tmp)/4; i++)
-        ((unsigned int*)&tmp)[i] = ByteReverse(((unsigned int*)&tmp)[i]);
-
-    // Precalc the first half of the first hash, which stays constant
-    SHA256Transform(pmidstate, &tmp.block, pSHA256InitState);
-
-    memcpy(pdata, &tmp.block, 128);
-    memcpy(phash1, &tmp.hash1, 64);
-}
-
-
-bool CheckWork(CBlock* pblock, CWallet& wallet, CReserveKey& reservekey)
-{
-    uint256 hash = pblock->GetHash();
-    uint256 hashTarget = CBigNum().SetCompact(pblock->nBits).getuint256();
-
-    if(!pblock->IsProofOfWork())
-        return error("CheckWork() : %s is not a proof-of-work block", hash.GetHex().c_str());
-
-    if (hash > hashTarget)
-        return error("CheckWork() : proof-of-work not meeting target");
-
-    //// debug print
-    printf("CheckWork() : new proof-of-stake block found  \n  hash: %s  \ntarget: %s\n", hash.GetHex().c_str(), hashTarget.GetHex().c_str());
-    pblock->print();
-    printf("generated %s\n", FormatMoney(pblock->vtx[0].vout[0].nValue).c_str());
-
-    // Found a solution
-    {
-        LOCK(cs_main);
-        if (pblock->hashPrevBlock != hashBestChain)
-            return error("CheckWork() : generated block is stale");
-
-        // Remove key from key pool
-        reservekey.KeepKey();
-
-        // Track how many getdata requests this block gets
-        {
-            LOCK(wallet.cs_wallet);
-            wallet.mapRequestCount[pblock->GetHash()] = 0;
-        }
-
-        // Process this block the same as if we had received it from another node
-        if (!ProcessBlock(NULL, pblock))
-            return error("CheckWork() : ProcessBlock, block not accepted");
-    }
-
-    return true;
-}
-
-bool CheckStake(CBlock* pblock, CWallet& wallet)
-{
-    uint256 proofHash = 0, hashTarget = 0;
-    uint256 hash = pblock->GetHash();
-
-    if(!pblock->IsProofOfStake())
-        return error("CheckStake() : %s is not a proof-of-stake block", hash.GetHex().c_str());
-
-    // verify hash target and signature of coinstake tx
-    if (!CheckProofOfStake(pblock->vtx[1], pblock->nBits, proofHash, hashTarget))
-        return error("CheckStake() : proof-of-stake checking failed");
-
-    //// debug print
-    printf("CheckStake() : new proof-of-stake block found  \n  hash: %s \nproofhash: %s  \ntarget: %s\n", hash.GetHex().c_str(), proofHash.GetHex().c_str(), hashTarget.GetHex().c_str());
-    pblock->print();
-    printf("out %s\n", FormatMoney(pblock->vtx[1].GetValueOut()).c_str());
-
-    // Found a solution
-    {
-        LOCK(cs_main);
-        if (pblock->hashPrevBlock != hashBestChain)
-            return error("CheckStake() : generated block is stale");
-
-        // Track how many getdata requests this block gets
-        {
-            LOCK(wallet.cs_wallet);
-            wallet.mapRequestCount[pblock->GetHash()] = 0;
-        }
-
-        // Process this block the same as if we had received it from another node
-        if (!ProcessBlock(NULL, pblock))
-            return error("CheckStake() : ProcessBlock, block not accepted");
-    }
-
-    return true;
-}
-
-void StakeMiner(CWallet *pwallet)
-{
-    SetThreadPriority(THREAD_PRIORITY_LOWEST);
-
-    // Make this thread recognisable as the mining thread
-    RenameThread("novacoin-miner");
-
-    // Each thread has its own counter
-    unsigned int nExtraNonce = 0;
-
-    while (true)
-    {
-        if (fShutdown)
-            return;
-        while (vNodes.empty() || IsInitialBlockDownload())
-        {
-            Sleep(1000);
-            if (fShutdown)
-                return;
-        }
-
-        while (pwallet->IsLocked())
-        {
-            strMintWarning = strMintMessage;
-            Sleep(1000);
-        }
-        strMintWarning = "";
-
-        //
-        // Create new block
-        //
-        CBlockIndex* pindexPrev = pindexBest;
-
-        auto_ptr<CBlock> pblock(CreateNewBlock(pwallet, true));
-        if (!pblock.get())
-            return;
-        IncrementExtraNonce(pblock.get(), pindexPrev, nExtraNonce);
-
-        if(pblock->IsProofOfStake())
-        {
-            // Trying to sign a block
-            if (!pblock->SignBlock(*pwalletMain))
-            {
-                strMintWarning = strMintMessage;
-                continue;
-            }
-
-            strMintWarning = "";
-            SetThreadPriority(THREAD_PRIORITY_NORMAL);
-            CheckStake(pblock.get(), *pwalletMain);
-            SetThreadPriority(THREAD_PRIORITY_LOWEST);
-        }
-
-        Sleep(500);
-        continue;
-    }
-}
-