Check last 288 block index records at startup.
[novacoin.git] / src / main.cpp
index 1befcb8..1e68aef 100644 (file)
@@ -1,20 +1,22 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2012 The Bitcoin developers
-// Copyright (c) 2011-2013 The PPCoin developers
 // Distributed under the MIT/X11 software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include "alert.h"
 #include "checkpoints.h"
 #include "db.h"
+#include "txdb.h"
 #include "net.h"
 #include "init.h"
 #include "ui_interface.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;
 
@@ -32,20 +34,32 @@ unsigned int nTransactionsUpdated = 0;
 
 map<uint256, CBlockIndex*> mapBlockIndex;
 set<pair<COutPoint, unsigned int> > setStakeSeen;
-uint256 hashGenesisBlock = hashGenesisBlockOfficial;
-static CBigNum bnProofOfWorkLimit(~uint256(0) >> 20);
-static CBigNum bnProofOfStakeLimit(~uint256(0) >> 24);
-static CBigNum bnProofOfStakeHardLimit(~uint256(0) >> 30);
-static CBigNum bnInitialHashTarget(~uint256(0) >> 20);
-unsigned int nStakeMinAge = STAKE_MIN_AGE;
-int nCoinbaseMaturity = COINBASE_MATURITY_PPC;
+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
+CBigNum bnProofOfStakeLimit(~uint256(0) >> 27); // proof of stake target limit since 20 June 2013, equal to 0.03125  proof of stake difficulty
+CBigNum bnProofOfStakeHardLimit(~uint256(0) >> 30); // disabled temporarily, will be used in the future to fix minimal proof of stake difficulty at 0.25
+uint256 nPoWBase = uint256("0x00000000ffff0000000000000000000000000000000000000000000000000000"); // difficulty-1 target
+
+CBigNum bnProofOfWorkLimitTestNet(~uint256(0) >> 16);
+
+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
+
+int nCoinbaseMaturity = 500;
 CBlockIndex* pindexGenesisBlock = NULL;
 int nBestHeight = -1;
-CBigNum bnBestChainTrust = 0;
-CBigNum bnBestInvalidTrust = 0;
+
+uint256 nBestChainTrust = 0;
+uint256 nBestInvalidTrust = 0;
+
 uint256 hashBestChain = 0;
 CBlockIndex* pindexBest = NULL;
 int64 nTimeBestReceived = 0;
+set<CBlockIndex*, CBlockIndexTrustComparator> setBlockIndexValid; // may contain all CBlockIndex*'s that have validness >=BLOCK_VALID_TRANSACTIONS, and must contain those who aren't failed
 
 CMedianFilter<int> cPeerBlockCounts(5, 0); // Amount of blocks that other nodes claim to have
 
@@ -54,21 +68,19 @@ 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;
 
 const string strMessageMagic = "NovaCoin Signed Message:\n";
 
-double dHashesPerSec;
-int64 nHPSTimerStart;
-
 // Settings
 int64 nTransactionFee = MIN_TX_FEE;
+int64 nMinimumInputValue = MIN_TX_FEE;
 
-
+extern enum Checkpoints::CPMode CheckpointsMode;
 
 //////////////////////////////////////////////////////////////////////////////
 //
@@ -120,7 +132,7 @@ void static EraseFromWallets(uint256 hash)
 }
 
 // make sure all wallets know about the given transaction, in the given block
-void static SyncWithWallets(const CTransaction& tx, const CBlock* pblock = NULL, bool fUpdate = false, bool fConnect = true)
+void SyncWithWallets(const uint256 &hash, const CTransaction& tx, const CBlock* pblock, bool fUpdate, bool fConnect)
 {
     if (!fConnect)
     {
@@ -135,7 +147,7 @@ void static SyncWithWallets(const CTransaction& tx, const CBlock* pblock = NULL,
     }
 
     BOOST_FOREACH(CWallet* pwallet, setpwalletRegistered)
-        pwallet->AddToWalletIfInvolvingMe(tx, pblock, fUpdate);
+        pwallet->AddToWalletIfInvolvingMe(hash, tx, pblock, fUpdate);
 }
 
 // notify wallets about a new best chain
@@ -167,33 +179,158 @@ void static Inventory(const uint256& hash)
 }
 
 // ask wallets to resend their transactions
-void ResendWalletTransactions()
+void ResendWalletTransactions(bool fForce)
 {
     BOOST_FOREACH(CWallet* pwallet, setpwalletRegistered)
-        pwallet->ResendWalletTransactions();
+        pwallet->ResendWalletTransactions(fForce);
+}
+
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// CCoinsView implementations
+//
+
+bool CCoinsView::GetCoins(uint256 txid, CCoins &coins) { return false; }
+bool CCoinsView::SetCoins(uint256 txid, const CCoins &coins) { return false; }
+bool CCoinsView::HaveCoins(uint256 txid) { return false; }
+CBlockIndex *CCoinsView::GetBestBlock() { return NULL; }
+bool CCoinsView::SetBestBlock(CBlockIndex *pindex) { return false; }
+bool CCoinsView::BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex) { return false; }
+bool CCoinsView::GetStats(CCoinsStats &stats) { return false; }
+
+CCoinsViewBacked::CCoinsViewBacked(CCoinsView &viewIn) : base(&viewIn) { }
+bool CCoinsViewBacked::GetCoins(uint256 txid, CCoins &coins) { return base->GetCoins(txid, coins); }
+bool CCoinsViewBacked::SetCoins(uint256 txid, const CCoins &coins) { return base->SetCoins(txid, coins); }
+bool CCoinsViewBacked::HaveCoins(uint256 txid) { return base->HaveCoins(txid); }
+CBlockIndex *CCoinsViewBacked::GetBestBlock() { return base->GetBestBlock(); }
+bool CCoinsViewBacked::SetBestBlock(CBlockIndex *pindex) { return base->SetBestBlock(pindex); }
+void CCoinsViewBacked::SetBackend(CCoinsView &viewIn) { base = &viewIn; }
+bool CCoinsViewBacked::GetStats(CCoinsStats &stats) { return base->GetStats(stats); }
+
+bool CCoinsViewBacked::BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex) { return base->BatchWrite(mapCoins, pindex); }
+
+CCoinsViewCache::CCoinsViewCache(CCoinsView &baseIn, bool fDummy) : CCoinsViewBacked(baseIn), pindexTip(NULL) { }
+
+bool CCoinsViewCache::GetCoins(uint256 txid, CCoins &coins) {
+    if (cacheCoins.count(txid)) {
+        coins = cacheCoins[txid];
+        return true;
+    }
+    if (base->GetCoins(txid, coins)) {
+        cacheCoins[txid] = coins;
+        return true;
+    }
+    return false;
+}
+
+// Select coins from read-only cache or database
+bool CCoinsViewCache::GetCoinsReadOnly(uint256 txid, CCoins &coins) {
+    if (cacheCoins.count(txid)) {
+        coins = cacheCoins[txid]; // get from cache
+        return true;
+    }
+    if (cacheCoinsReadOnly.count(txid)) {
+        coins = cacheCoinsReadOnly[txid]; // get from read-only cache
+        return true;
+    }
+    if (base->GetCoins(txid, coins)) {
+        cacheCoinsReadOnly[txid] = coins; // save to read-only cache
+        return true;
+    }
+    return false;
+}
+
+std::map<uint256,CCoins>::iterator CCoinsViewCache::FetchCoins(uint256 txid) {
+    std::map<uint256,CCoins>::iterator it = cacheCoins.find(txid);
+    if (it != cacheCoins.end())
+        return it;
+    CCoins tmp;
+    if (!base->GetCoins(txid,tmp))
+        return it;
+    std::pair<std::map<uint256,CCoins>::iterator,bool> ret = cacheCoins.insert(std::make_pair(txid, tmp));
+    return ret.first;
+}
+
+CCoins &CCoinsViewCache::GetCoins(uint256 txid) {
+    std::map<uint256,CCoins>::iterator it = FetchCoins(txid);
+    assert(it != cacheCoins.end());
+    return it->second;
+}
+
+bool CCoinsViewCache::SetCoins(uint256 txid, const CCoins &coins) {
+    cacheCoins[txid] = coins;
+    return true;
+}
+
+bool CCoinsViewCache::HaveCoins(uint256 txid) {
+    return FetchCoins(txid) != cacheCoins.end();
+}
+
+CBlockIndex *CCoinsViewCache::GetBestBlock() {
+    if (pindexTip == NULL)
+        pindexTip = base->GetBestBlock();
+    return pindexTip;
+}
+
+bool CCoinsViewCache::SetBestBlock(CBlockIndex *pindex) {
+    pindexTip = pindex;
+    return true;
 }
 
+bool CCoinsViewCache::BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex) {
+    for (std::map<uint256, CCoins>::const_iterator it = mapCoins.begin(); it != mapCoins.end(); it++)
+        cacheCoins[it->first] = it->second;
+    pindexTip = pindex;
+    return true;
+}
 
+bool CCoinsViewCache::Flush() {
+    cacheCoinsReadOnly.clear(); // purge read-only cache
 
+    bool fOk = base->BatchWrite(cacheCoins, pindexTip);
+    if (fOk)
+        cacheCoins.clear();
+    return fOk;
+}
 
+unsigned int CCoinsViewCache::GetCacheSize() {
+    return cacheCoins.size();
+}
 
+/** CCoinsView that brings transactions from a memorypool into view.
+    It does not check for spendings by memory pool transactions. */
+CCoinsViewMemPool::CCoinsViewMemPool(CCoinsView &baseIn, CTxMemPool &mempoolIn) : CCoinsViewBacked(baseIn), mempool(mempoolIn) { }
 
+bool CCoinsViewMemPool::GetCoins(uint256 txid, CCoins &coins) {
+    if (base->GetCoins(txid, coins))
+        return true;
+    if (mempool.exists(txid)) {
+        const CTransaction &tx = mempool.lookup(txid);
+        coins = CCoins(tx, MEMPOOL_HEIGHT, -1);
+        return true;
+    }
+    return false;
+}
+
+bool CCoinsViewMemPool::HaveCoins(uint256 txid) {
+    return mempool.exists(txid) || base->HaveCoins(txid);
+}
+
+CCoinsViewCache *pcoinsTip = NULL;
+CBlockTreeDB *pblocktree = NULL;
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // 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
@@ -201,18 +338,20 @@ 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: %u, 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 %u)\n", hash.ToString().substr(0,10).c_str(),
+    printf("stored orphan tx %s (mapsz %"PRIszu")\n", hash.ToString().substr(0,10).c_str(),
         mapOrphanTransactions.size());
     return true;
 }
@@ -221,16 +360,13 @@ 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);
 }
 
@@ -241,7 +377,7 @@ 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);
@@ -258,52 +394,54 @@ unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans)
 
 //////////////////////////////////////////////////////////////////////////////
 //
-// CTransaction and CTxIndex
+// CTransaction
 //
 
-bool CTransaction::ReadFromDisk(CTxDB& txdb, COutPoint prevout, CTxIndex& txindexRet)
+bool CTransaction::IsStandard() const
 {
-    SetNull();
-    if (!txdb.ReadTxIndex(prevout.hash, txindexRet))
-        return false;
-    if (!ReadFromDisk(txindexRet.pos))
-        return false;
-    if (prevout.n >= vout.size())
-    {
-        SetNull();
+    if (nVersion > CTransaction::CURRENT_VERSION) {
         return false;
     }
-    return true;
-}
-
-bool CTransaction::ReadFromDisk(CTxDB& txdb, COutPoint prevout)
-{
-    CTxIndex txindex;
-    return ReadFromDisk(txdb, prevout, txindex);
-}
 
-bool CTransaction::ReadFromDisk(COutPoint prevout)
-{
-    CTxDB txdb("r");
-    CTxIndex txindex;
-    return ReadFromDisk(txdb, prevout, txindex);
-}
-
-bool CTransaction::IsStandard() const
-{
     BOOST_FOREACH(const CTxIn& txin, vin)
     {
         // Biggest 'standard' txin is a 3-signature 3-of-3 CHECKMULTISIG
         // pay-to-script-hash, which is 3 ~80-byte signatures, 3
         // ~65-byte public keys, plus a few script ops.
-        if (txin.scriptSig.size() > 500)
+        if (txin.scriptSig.size() > 500) {
             return false;
-        if (!txin.scriptSig.IsPushOnly())
+        }
+        if (!txin.scriptSig.IsPushOnly()) {
             return false;
+        }
+        if (fEnforceCanonical && !txin.scriptSig.HasCanonicalPushes()) {
+            return false;
+        }
     }
-    BOOST_FOREACH(const CTxOut& txout, vout)
-        if (!::IsStandard(txout.scriptPubKey))
+
+    unsigned int nDataOut = 0;
+    txnouttype whichType;
+    BOOST_FOREACH(const CTxOut& txout, vout) {
+        if (!::IsStandard(txout.scriptPubKey, whichType)) {
             return false;
+        }
+        if (whichType == TX_NULL_DATA)
+            nDataOut++;
+        else {
+            if (txout.nValue == 0) {
+                return false;
+            }
+            if (fEnforceCanonical && !txout.scriptPubKey.HasCanonicalPushes()) {
+                return false;
+            }
+        }
+    }
+
+    // only one OP_RETURN txout is permitted
+    if (nDataOut > 1) {
+        return false;
+    }
+
     return true;
 }
 
@@ -318,7 +456,7 @@ bool CTransaction::IsStandard() const
 // expensive-to-check-upon-redemption script like:
 //   DUP CHECKSIG DROP ... repeated 100 times... OP_1
 //
-bool CTransaction::AreInputsStandard(const MapPrevTx& mapInputs) const
+bool CTransaction::AreInputsStandard(CCoinsViewCache& mapInputs) const
 {
     if (IsCoinBase())
         return true; // Coinbases don't use vin normally
@@ -343,7 +481,7 @@ 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)
@@ -398,17 +536,19 @@ int CMerkleTx::SetMerkleBranch(const CBlock* pblock)
     else
     {
         CBlock blockTmp;
-        if (pblock == NULL)
-        {
-            // Load the block this tx is in
-            CTxIndex txindex;
-            if (!CTxDB("r").ReadTxIndex(GetHash(), txindex))
-                return 0;
-            if (!blockTmp.ReadFromDisk(txindex.pos.nFile, txindex.pos.nBlockPos))
-                return 0;
-            pblock = &blockTmp;
+        if (pblock == NULL) {
+            CCoins coins;
+            if (pcoinsTip->GetCoins(GetHash(), coins)) {
+                CBlockIndex *pindex = FindBlockByHeight(coins.nHeight);
+                if (pindex) {
+                    if (!blockTmp.ReadFromDisk(pindex))
+                        return 0;
+                    pblock = &blockTmp;
+                }
+            }
         }
 
+        if (pblock) {
         // Update the tx's hashBlock
         hashBlock = pblock->GetHash();
 
@@ -426,6 +566,7 @@ int CMerkleTx::SetMerkleBranch(const CBlock* pblock)
 
         // Fill in merkle branch
         vMerkleBranch = pblock->GetMerkleBranch(nIndex);
+        }
     }
 
     // Is the tx in a block that's in the main chain
@@ -439,12 +580,6 @@ int CMerkleTx::SetMerkleBranch(const CBlock* pblock)
     return pindexBest->nHeight - pindex->nHeight + 1;
 }
 
-
-
-
-
-
-
 bool CTransaction::CheckTransaction() const
 {
     // Basic checks that don't depend on any context
@@ -458,14 +593,18 @@ bool CTransaction::CheckTransaction() const
 
     // Check for negative or overflow output values
     int64 nValueOut = 0;
-    for (int i = 0; i < vout.size(); i++)
+    for (unsigned int i = 0; i < vout.size(); i++)
     {
         const CTxOut& txout = vout[i];
-        if (txout.IsEmpty() && (!IsCoinBase()) && (!IsCoinStake()))
+        if (txout.IsEmpty() && !IsCoinBase() && !IsCoinStake())
             return DoS(100, error("CTransaction::CheckTransaction() : txout empty for user transaction"));
-        // ppcoin: enforce minimum output amount
-        if ((!txout.IsEmpty()) && txout.nValue < MIN_TXOUT_AMOUNT)
+
+        // Enforce minimum output amount for user transactions until 1 May 2014 04:00:00 GMT
+        if (!fTestNet && !IsCoinBase() && !txout.IsEmpty() && nTime < OUTPUT_SWITCH_TIME && 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;
@@ -485,7 +624,7 @@ bool CTransaction::CheckTransaction() const
     if (IsCoinBase())
     {
         if (vin[0].scriptSig.size() < 2 || vin[0].scriptSig.size() > 100)
-            return DoS(100, error("CTransaction::CheckTransaction() : coinbase script size"));
+            return DoS(100, error("CTransaction::CheckTransaction() : coinbase script size is invalid"));
     }
     else
     {
@@ -497,8 +636,50 @@ bool CTransaction::CheckTransaction() const
     return true;
 }
 
-bool CTxMemPool::accept(CTxDB& txdb, CTransaction &tx, bool fCheckInputs,
-                        bool* pfMissingInputs)
+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;
+
+    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)
+    {
+        BOOST_FOREACH(const CTxOut& txout, vout)
+            if (txout.nValue < CENT)
+                nMinFee = nBaseFee;
+    }
+
+    // Raise the price as the block approaches full
+    if (nBlockSize != 1 && nNewBlockSize >= MAX_BLOCK_SIZE_GEN/2)
+    {
+        if (nNewBlockSize >= MAX_BLOCK_SIZE_GEN)
+            return MAX_MONEY;
+        nMinFee *= MAX_BLOCK_SIZE_GEN / (MAX_BLOCK_SIZE_GEN - nNewBlockSize);
+    }
+
+    if (!MoneyRange(nMinFee))
+        nMinFee = MAX_MONEY;
+    return nMinFee;
+}
+
+void CTxMemPool::pruneSpent(const uint256 &hashTx, CCoins &coins)
+{
+    LOCK(cs);
+
+    std::map<COutPoint, CInPoint>::iterator it = mapNextTx.lower_bound(COutPoint(hashTx, 0));
+
+    // iterate over all COutPoints in mapNextTx whose hash equals the provided hashTx
+    while (it != mapNextTx.end() && it->first.hash == hashTx) {
+        coins.Spend(it->first.n); // and remove those outputs from coins
+        it++;
+    }
+}
+
+bool CTxMemPool::accept(CTransaction &tx, bool fCheckInputs, bool* pfMissingInputs)
 {
     if (pfMissingInputs)
         *pfMissingInputs = false;
@@ -509,7 +690,8 @@ bool CTxMemPool::accept(CTxDB& txdb, CTransaction &tx, bool fCheckInputs,
     // Coinbase is only valid in a block, not as a loose transaction
     if (tx.IsCoinBase())
         return tx.DoS(100, error("CTxMemPool::accept() : coinbase as individual tx"));
-    // ppcoin: coinstake is also only valid in a block, not as a loose transaction
+
+    // Coinstake is also only valid in a block, not as a loose transaction
     if (tx.IsCoinStake())
         return tx.DoS(100, error("CTxMemPool::accept() : coinstake as individual tx"));
 
@@ -521,16 +703,13 @@ bool CTxMemPool::accept(CTxDB& txdb, CTransaction &tx, bool fCheckInputs,
     if (!fTestNet && !tx.IsStandard())
         return error("CTxMemPool::accept() : nonstandard transaction type");
 
-    // Do we already have it?
+    // is it already in the memory pool?
     uint256 hash = tx.GetHash();
     {
         LOCK(cs);
         if (mapTx.count(hash))
             return false;
     }
-    if (fCheckInputs)
-        if (txdb.ContainsTx(hash))
-            return false;
 
     // Check for conflicts with in-memory transactions
     CTransaction* ptxOld = NULL;
@@ -562,36 +741,46 @@ bool CTxMemPool::accept(CTxDB& txdb, CTransaction &tx, bool fCheckInputs,
 
     if (fCheckInputs)
     {
-        MapPrevTx mapInputs;
-        map<uint256, CTxIndex> mapUnused;
-        bool fInvalid = false;
-        if (!tx.FetchInputs(txdb, mapUnused, false, false, mapInputs, fInvalid))
-        {
-            if (fInvalid)
-                return error("CTxMemPool::accept() : FetchInputs found invalid tx %s", hash.ToString().substr(0,10).c_str());
-            if (pfMissingInputs)
-                *pfMissingInputs = true;
-            return error("CTxMemPool::accept() : FetchInputs failed %s", hash.ToString().substr(0,10).c_str());
+        CCoinsViewCache &view = *pcoinsTip;
+
+        // do we already have it?
+        if (view.HaveCoins(hash))
+            return false;
+
+        // do all inputs exist?
+        BOOST_FOREACH(const CTxIn txin, tx.vin) {
+            if (!view.HaveCoins(txin.prevout.hash)) {
+                if (pfMissingInputs)
+                    *pfMissingInputs = true;
+                return false;
+            }
         }
 
+        if (!tx.HaveInputs(view))
+            return error("CTxMemPool::accept() : inputs already spent");
+
         // Check for non-standard pay-to-script-hash in inputs
-        if (!tx.AreInputsStandard(mapInputs) && !fTestNet)
+        if (!tx.AreInputsStandard(view) && !fTestNet)
             return error("CTxMemPool::accept() : nonstandard transaction input");
 
         // Note: if you modify this code to accept non-standard transactions, then
         // you should add code here to check that the transaction does a
         // reasonable number of ECDSA signature verifications.
 
-        int64 nFees = tx.GetValueIn(mapInputs)-tx.GetValueOut();
+        int64 nFees = tx.GetValueIn(view)-tx.GetValueOut();
         unsigned int nSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
 
         // Don't accept it if it can't get into a block
-        if (nFees < tx.GetMinFee(1000, false, GMF_RELAY))
-            return error("CTxMemPool::accept() : not enough fees");
+        int64 txMinFee = tx.GetMinFee(1000, false, GMF_RELAY, nSize);
+        if (nFees < txMinFee)
+            return error("CTxMemPool::accept() : not enough fees %s, %"PRI64d" < %"PRI64d,
+                         hash.ToString().c_str(),
+                         nFees, txMinFee);
+
 
         // Continuously rate-limit free transactions
         // This mitigates 'penny-flooding' -- sending thousands of free transactions just to
-        // be annoying or make other's transactions take longer to confirm.
+        // be annoying or make others' transactions take longer to confirm.
         if (nFees < MIN_RELAY_TX_FEE)
         {
             static CCriticalSection cs;
@@ -616,7 +805,7 @@ 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.CheckInputs(view, CS_ALWAYS, true, false))
         {
             return error("CTxMemPool::accept() : ConnectInputs failed %s", hash.ToString().substr(0,10).c_str());
         }
@@ -630,7 +819,7 @@ bool CTxMemPool::accept(CTxDB& txdb, CTransaction &tx, bool fCheckInputs,
             printf("CTxMemPool::accept() : replacing tx %s with new version\n", ptxOld->GetHash().ToString().c_str());
             remove(*ptxOld);
         }
-        addUnchecked(tx);
+        addUnchecked(hash, tx);
     }
 
     ///// are we sure this is ok when loading transactions or restoring block txes
@@ -638,23 +827,22 @@ bool CTxMemPool::accept(CTxDB& txdb, CTransaction &tx, bool fCheckInputs,
     if (ptxOld)
         EraseFromWallets(ptxOld->GetHash());
 
-    printf("CTxMemPool::accept() : accepted %s\n", hash.ToString().substr(0,10).c_str());
+    printf("CTxMemPool::accept() : accepted %s (poolsz %"PRIszu")\n",
+           hash.ToString().substr(0,10).c_str(),
+           mapTx.size());
     return true;
 }
 
-bool CTransaction::AcceptToMemoryPool(CTxDB& txdb, bool fCheckInputs, bool* pfMissingInputs)
+bool CTransaction::AcceptToMemoryPool(bool fCheckInputs, bool* pfMissingInputs)
 {
-    return mempool.accept(txdb, *this, fCheckInputs, pfMissingInputs);
+    return mempool.accept(*this, fCheckInputs, pfMissingInputs);
 }
 
-bool CTxMemPool::addUnchecked(CTransaction &tx)
+bool CTxMemPool::addUnchecked(const uint256& hash, CTransaction &tx)
 {
-    printf("addUnchecked(): size %lu\n",  mapTx.size());
     // Add to memory pool without checking anything.  Don't call this directly,
     // call CTxMemPool::accept to properly check the transaction first.
     {
-        LOCK(cs);
-        uint256 hash = tx.GetHash();
         mapTx[hash] = tx;
         for (unsigned int i = 0; i < tx.vin.size(); i++)
             mapNextTx[tx.vin[i].prevout] = CInPoint(&mapTx[hash], i);
@@ -681,24 +869,52 @@ bool CTxMemPool::remove(CTransaction &tx)
     return true;
 }
 
+void CTxMemPool::clear()
+{
+    LOCK(cs);
+    mapTx.clear();
+    mapNextTx.clear();
+    ++nTransactionsUpdated;
+}
+
+void CTxMemPool::queryHashes(std::vector<uint256>& vtxid)
+{
+    vtxid.clear();
+
+    LOCK(cs);
+    vtxid.reserve(mapTx.size());
+    for (map<uint256, CTransaction>::iterator mi = mapTx.begin(); mi != mapTx.end(); ++mi)
+        vtxid.push_back((*mi).first);
+}
+
+// Return depth of transaction in blockchain:
+// -1  : not in blockchain, and not in memory pool (conflicted transaction)
+//  0  : in memory pool, waiting to be included in a block
+// >=1 : this many blocks deep in the main chain
 int CMerkleTx::GetDepthInMainChain(CBlockIndex* &pindexRet) const
 {
-    if (hashBlock == 0 || nIndex == -1)
-        return 0;
+    bool fInMemPool = mempool.exists(GetHash());
+
+    if (hashBlock == 0 || nIndex == -1) {
+        return fInMemPool ? 0 : -1;
+    }
 
     // Find the block it claims to be in
     map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(hashBlock);
-    if (mi == mapBlockIndex.end())
-        return 0;
+    if (mi == mapBlockIndex.end()) {
+        return fInMemPool ? 0 : -1;
+    }
     CBlockIndex* pindex = (*mi).second;
-    if (!pindex || !pindex->IsInMainChain())
-        return 0;
+    if (!pindex || !pindex->IsInMainChain()) {
+        return fInMemPool ? 0 : -1;
+    }
 
     // Make sure the merkle branch connects to this block
     if (!fMerkleVerified)
     {
-        if (CBlock::CheckMerkleBranch(GetHash(), vMerkleBranch, nIndex) != pindex->hashMerkleRoot)
-            return 0;
+        if (CBlock::CheckMerkleBranch(GetHash(), vMerkleBranch, nIndex) != pindex->hashMerkleRoot) {
+            return fInMemPool ? 0 : -1;
+        }
         fMerkleVerified = true;
     }
 
@@ -706,7 +922,6 @@ int CMerkleTx::GetDepthInMainChain(CBlockIndex* &pindexRet) const
     return pindexBest->nHeight - pindex->nHeight + 1;
 }
 
-
 int CMerkleTx::GetBlocksToMaturity() const
 {
     if (!(IsCoinBase() || IsCoinStake()))
@@ -715,27 +930,21 @@ int CMerkleTx::GetBlocksToMaturity() const
 }
 
 
-bool CMerkleTx::AcceptToMemoryPool(CTxDB& txdb, bool fCheckInputs)
+bool CMerkleTx::AcceptToMemoryPool(bool fCheckInputs)
 {
     if (fClient)
     {
-        if (!IsInMainChain() && !ClientConnectInputs())
+        if (!IsInMainChain() && !ClientCheckInputs())
             return false;
-        return CTransaction::AcceptToMemoryPool(txdb, false);
+        return CTransaction::AcceptToMemoryPool(false);
     }
     else
     {
-        return CTransaction::AcceptToMemoryPool(txdb, fCheckInputs);
+        return CTransaction::AcceptToMemoryPool(fCheckInputs);
     }
 }
 
-bool CMerkleTx::AcceptToMemoryPool()
-{
-    CTxDB txdb("r");
-    return AcceptToMemoryPool(txdb);
-}
-
-bool CWalletTx::AcceptWalletTransaction(CTxDB& txdb, bool fCheckInputs)
+bool CWalletTx::AcceptWalletTransaction(bool fCheckInputs)
 {
 
     {
@@ -746,68 +955,83 @@ bool CWalletTx::AcceptWalletTransaction(CTxDB& txdb, bool fCheckInputs)
             if (!(tx.IsCoinBase() || tx.IsCoinStake()))
             {
                 uint256 hash = tx.GetHash();
-                if (!mempool.exists(hash) && !txdb.ContainsTx(hash))
-                    tx.AcceptToMemoryPool(txdb, fCheckInputs);
+                if (!mempool.exists(hash) && pcoinsTip->HaveCoins(hash))
+                    tx.AcceptToMemoryPool(fCheckInputs);
             }
         }
-        return AcceptToMemoryPool(txdb, fCheckInputs);
+        return AcceptToMemoryPool(fCheckInputs);
     }
     return false;
 }
 
-bool CWalletTx::AcceptWalletTransaction()
-{
-    CTxDB txdb("r");
-    return AcceptWalletTransaction(txdb);
-}
-
-int CTxIndex::GetDepthInMainChain() const
-{
-    // Read block header
-    CBlock block;
-    if (!block.ReadFromDisk(pos.nFile, pos.nBlockPos, false))
-        return 0;
-    // Find the block in the index
-    map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(block.GetHash());
-    if (mi == mapBlockIndex.end())
-        return 0;
-    CBlockIndex* pindex = (*mi).second;
-    if (!pindex || !pindex->IsInMainChain())
-        return 0;
-    return 1 + nBestHeight - pindex->nHeight;
-}
-
 // Return transaction in tx, and if it was found inside a block, its hash is placed in hashBlock
-bool GetTransaction(const uint256 &hash, CTransaction &tx, uint256 &hashBlock)
+bool GetTransaction(const uint256 &hash, CTransaction &txOut, uint256 &hashBlock, bool fAllowSlow)
 {
+    CBlockIndex *pindexSlow = NULL;
     {
         LOCK(cs_main);
         {
             LOCK(mempool.cs);
             if (mempool.exists(hash))
             {
-                tx = mempool.lookup(hash);
+                txOut = mempool.lookup(hash);
                 return true;
             }
         }
-        CTxDB txdb("r");
-        CTxIndex txindex;
-        if (tx.ReadFromDisk(txdb, COutPoint(hash, 0), txindex))
-        {
-            CBlock block;
-            if (block.ReadFromDisk(txindex.pos.nFile, txindex.pos.nBlockPos, false))
-                hashBlock = block.GetHash();
-            return true;
+
+        if (fAllowSlow) { // use coin database to locate block that contains transaction, and scan it
+            int nHeight = -1;
+            {
+                CCoinsViewCache &view = *pcoinsTip;
+                CCoins coins;
+                if (view.GetCoins(hash, coins))
+                    nHeight = coins.nHeight;
+            }
+            if (nHeight > 0)
+                pindexSlow = FindBlockByHeight(nHeight);
         }
     }
+
+    if (pindexSlow) {
+        CBlock block;
+        if (block.ReadFromDisk(pindexSlow)) {
+            BOOST_FOREACH(const CTransaction &tx, block.vtx) {
+                if (tx.GetHash() == hash) {
+                    txOut = tx;
+                    hashBlock = pindexSlow->GetBlockHash();
+                    return true;
+                }
+            }
+        }
+    }
+
     return false;
 }
 
+
 //////////////////////////////////////////////////////////////////////////////
 //
 // CBlock and CBlockIndex
 //
 
+static CBlockIndex* pblockindexFBBHLast;
+CBlockIndex* FindBlockByHeight(int nHeight)
+{
+    CBlockIndex *pblockindex;
+    if (nHeight < nBestHeight / 2)
+        pblockindex = pindexGenesisBlock;
+    else
+        pblockindex = pindexBest;
+    if (pblockindexFBBHLast && abs(nHeight - pblockindex->nHeight) > abs(nHeight - pblockindexFBBHLast->nHeight))
+        pblockindex = pblockindexFBBHLast;
+    while (pblockindex->nHeight > nHeight)
+        pblockindex = pblockindex->pprev;
+    while (pblockindex->nHeight < nHeight)
+        pblockindex = pblockindex->pnext;
+    pblockindexFBBHLast = pblockindex;
+    return pblockindex;
+}
+
 bool CBlock::ReadFromDisk(const CBlockIndex* pindex, bool fReadTransactions)
 {
     if (!fReadTransactions)
@@ -815,7 +1039,7 @@ bool CBlock::ReadFromDisk(const CBlockIndex* pindex, bool fReadTransactions)
         *this = pindex->GetBlockHeader();
         return true;
     }
-    if (!ReadFromDisk(pindex->nFile, pindex->nBlockPos, fReadTransactions))
+    if (!ReadFromDisk(pindex->GetBlockPos(), fReadTransactions))
         return false;
     if (GetHash() != pindex->GetBlockHash())
         return error("CBlock::ReadFromDisk() : GetHash() doesn't match index");
@@ -839,15 +1063,32 @@ uint256 WantedByOrphan(const CBlock* pblockOrphan)
     return pblockOrphan->hashPrevBlock;
 }
 
+// select stake target limit according to hard-coded conditions
+CBigNum inline GetProofOfStakeLimit(int nHeight, unsigned int nTime)
+{
+    if(fTestNet) // separate proof of stake target limit for testnet
+        return bnProofOfStakeLimit;
+    if(nTime > TARGETS_SWITCH_TIME) // 27 bits since 20 July 2013
+        return bnProofOfStakeLimit;
+    if(nHeight + 1 > 15000) // 24 bits since block 15000
+        return bnProofOfStakeLegacyLimit;
+    if(nHeight + 1 > 14060) // 31 bits since block 14060 until 15000
+        return bnProofOfStakeHardLimit;
+
+    return bnProofOfWorkLimit; // return bnProofOfWorkLimit of none matched
+}
+
+// miner's coin base reward based on nBits
 int64 GetProofOfWorkReward(unsigned int nBits)
 {
     CBigNum bnSubsidyLimit = MAX_MINT_PROOF_OF_WORK;
+
     CBigNum bnTarget;
     bnTarget.SetCompact(nBits);
     CBigNum bnTargetLimit = bnProofOfWorkLimit;
     bnTargetLimit.SetCompact(bnTargetLimit.GetCompact());
 
-    // ppcoin: subsidy is cut in half every 64x multiply of difficulty
+    // NovaCoin: subsidy is cut in half every 64x multiply of PoW difficulty
     // A reasonably continuous curve is used to avoid shock to market
     // (nSubsidyLimit / nSubsidy) ** 6 == bnProofOfWorkLimit / bnTarget
     //
@@ -868,6 +1109,7 @@ int64 GetProofOfWorkReward(unsigned int nBits)
     }
 
     int64 nSubsidy = bnUpperBound.getuint64();
+
     nSubsidy = (nSubsidy / CENT) * CENT;
     if (fDebug && GetBoolArg("-printcreation"))
         printf("GetProofOfWorkReward() : create=%s nBits=0x%08x nSubsidy=%"PRI64d"\n", FormatMoney(nSubsidy).c_str(), nBits, nSubsidy);
@@ -875,36 +1117,115 @@ int64 GetProofOfWorkReward(unsigned int nBits)
     return min(nSubsidy, MAX_MINT_PROOF_OF_WORK);
 }
 
-// ppcoin: miner's coin stake is rewarded based on coin age spent (coin-days)
-int64 GetProofOfStakeReward(int64 nCoinAge)
+// miner's coin stake reward based on nBits and coin age spent (coin-days)
+int64 GetProofOfStakeReward(int64 nCoinAge, unsigned int nBits, unsigned int nTime, bool bCoinYearOnly)
 {
-    static int64 nRewardCoinYear = 5 * CENT;  // creation amount per coin-year
-    int64 nSubsidy = nCoinAge * 33 / (365 * 33 + 8) * nRewardCoinYear;
+    int64 nRewardCoinYear, nSubsidy, nSubsidyLimit = 10 * COIN;
+
+    if(fTestNet || nTime > STAKE_SWITCH_TIME)
+    {
+        // Stage 2 of emission process is PoS-based. It will be active on mainNet since 20 Jun 2013.
+
+        CBigNum bnRewardCoinYearLimit = MAX_MINT_PROOF_OF_STAKE; // Base stake mint rate, 100% year interest
+        CBigNum bnTarget;
+        bnTarget.SetCompact(nBits);
+        CBigNum bnTargetLimit = GetProofOfStakeLimit(0, nTime);
+        bnTargetLimit.SetCompact(bnTargetLimit.GetCompact());
+
+        // NovaCoin: A reasonably continuous curve is used to avoid shock to market
+
+        CBigNum bnLowerBound = 1 * CENT, // Lower interest bound is 1% per year
+            bnUpperBound = bnRewardCoinYearLimit, // Upper interest bound is 100% per year
+            bnMidPart, bnRewardPart;
+
+        while (bnLowerBound + CENT <= bnUpperBound)
+        {
+            CBigNum bnMidValue = (bnLowerBound + bnUpperBound) / 2;
+            if (fDebug && GetBoolArg("-printcreation"))
+                printf("GetProofOfStakeReward() : lower=%"PRI64d" upper=%"PRI64d" mid=%"PRI64d"\n", bnLowerBound.getuint64(), bnUpperBound.getuint64(), bnMidValue.getuint64());
+
+            if(!fTestNet && nTime < STAKECURVE_SWITCH_TIME)
+            {
+                //
+                // Until 20 Oct 2013: reward for coin-year is cut in half every 64x multiply of PoS difficulty
+                //
+                // (nRewardCoinYearLimit / nRewardCoinYear) ** 6 == bnProofOfStakeLimit / bnTarget
+                //
+                // Human readable form: nRewardCoinYear = 1 / (posdiff ^ 1/6)
+                //
+
+                bnMidPart = bnMidValue * bnMidValue * bnMidValue * bnMidValue * bnMidValue * bnMidValue;
+                bnRewardPart = bnRewardCoinYearLimit * bnRewardCoinYearLimit * bnRewardCoinYearLimit * bnRewardCoinYearLimit * bnRewardCoinYearLimit * bnRewardCoinYearLimit;
+            }
+            else
+            {
+                //
+                // Since 20 Oct 2013: reward for coin-year is cut in half every 8x multiply of PoS difficulty
+                //
+                // (nRewardCoinYearLimit / nRewardCoinYear) ** 3 == bnProofOfStakeLimit / bnTarget
+                //
+                // Human readable form: nRewardCoinYear = 1 / (posdiff ^ 1/3)
+                //
+
+                bnMidPart = bnMidValue * bnMidValue * bnMidValue;
+                bnRewardPart = bnRewardCoinYearLimit * bnRewardCoinYearLimit * bnRewardCoinYearLimit;
+            }
+
+            if (bnMidPart * bnTargetLimit > bnRewardPart * bnTarget)
+                bnUpperBound = bnMidValue;
+            else
+                bnLowerBound = bnMidValue;
+        }
+
+        nRewardCoinYear = bnUpperBound.getuint64();
+        nRewardCoinYear = min((nRewardCoinYear / CENT) * CENT, MAX_MINT_PROOF_OF_STAKE);
+    }
+    else
+    {
+        // Old creation amount per coin-year, 5% fixed stake mint rate
+        nRewardCoinYear = 5 * CENT;
+    }
+
+    if(bCoinYearOnly)
+        return nRewardCoinYear;
+
+    nSubsidy = nCoinAge * nRewardCoinYear * 33 / (365 * 33 + 8);
+
+    // Set reasonable reward limit for large inputs since 20 Oct 2013
+    //
+    // This will stimulate large holders to use smaller inputs, that's good for the network protection
+    if(fTestNet || STAKECURVE_SWITCH_TIME < nTime)
+    {
+        if (fDebug && GetBoolArg("-printcreation") && nSubsidyLimit < nSubsidy)
+            printf("GetProofOfStakeReward(): %s is greater than %s, coinstake reward will be truncated\n", FormatMoney(nSubsidy).c_str(), FormatMoney(nSubsidyLimit).c_str());
+
+        nSubsidy = min(nSubsidy, nSubsidyLimit);
+    }
+
     if (fDebug && GetBoolArg("-printcreation"))
-        printf("GetProofOfStakeReward(): create=%s nCoinAge=%"PRI64d"\n", FormatMoney(nSubsidy).c_str(), nCoinAge);
+        printf("GetProofOfStakeReward(): create=%s nCoinAge=%"PRI64d" nBits=%d\n", FormatMoney(nSubsidy).c_str(), nCoinAge, nBits);
     return nSubsidy;
 }
 
 static const int64 nTargetTimespan = 7 * 24 * 60 * 60;  // one week
-static const int64 nTargetSpacingWorkMax = 12 * STAKE_TARGET_SPACING; // 2-hour
 
-//
-// minimum amount of work that could possibly be required nTime after
-// minimum work required was nBase
-//
-unsigned int ComputeMinWork(unsigned int nBase, int64 nTime, bool fProofOfStake, int nHeight)
+// get proof of work blocks max spacing according to hard-coded conditions
+int64 inline GetTargetSpacingWorkMax(int nHeight, unsigned int nTime)
 {
-    CBigNum bnTargetLimit = bnProofOfWorkLimit;
+    if(nTime > TARGETS_SWITCH_TIME)
+        return 3 * nStakeTargetSpacing; // 30 minutes on mainNet since 20 Jul 2013 00:00:00
 
-    if(fProofOfStake)
-    {
-        // Proof-of-Stake blocks has own target limit since nVersion=3 supermajority on mainNet and always on testNet
-        if(fTestNet || nHeight > 15000)
-            bnTargetLimit = bnProofOfStakeLimit;
-        else if(nHeight > 14060)
-            bnTargetLimit = bnProofOfStakeHardLimit;
-    }
+    if(fTestNet)
+        return 3 * nStakeTargetSpacing; // 15 minutes on testNet
+
+    return 12 * nStakeTargetSpacing; // 2 hours otherwise
+}
 
+//
+// maximum nBits value could possible be required nTime after
+//
+unsigned int ComputeMaxBits(CBigNum bnTargetLimit, unsigned int nBase, int64 nTime)
+{
     CBigNum bnResult;
     bnResult.SetCompact(nBase);
     bnResult *= 2;
@@ -919,6 +1240,25 @@ unsigned int ComputeMinWork(unsigned int nBase, int64 nTime, bool fProofOfStake,
     return bnResult.GetCompact();
 }
 
+//
+// minimum amount of work that could possibly be required nTime after
+// minimum proof-of-work required was nBase
+//
+unsigned int ComputeMinWork(unsigned int nBase, int64 nTime)
+{
+    return ComputeMaxBits(bnProofOfWorkLimit, nBase, nTime);
+}
+
+//
+// minimum amount of stake that could possibly be required nTime after
+// minimum proof-of-stake required was nBase
+//
+unsigned int ComputeMinStake(unsigned int nBase, int64 nTime, unsigned int nBlockTime)
+{
+    return ComputeMaxBits(GetProofOfStakeLimit(0, nBlockTime), nBase, nTime);
+}
+
+
 // ppcoin: find last block index up to pindex
 const CBlockIndex* GetLastBlockIndex(const CBlockIndex* pindex, bool fProofOfStake)
 {
@@ -927,28 +1267,19 @@ const CBlockIndex* GetLastBlockIndex(const CBlockIndex* pindex, bool fProofOfSta
     return pindex;
 }
 
-unsigned int static GetNextTargetRequired(const CBlockIndex* pindexLast, bool fProofOfStake)
+unsigned int GetNextTargetRequired(const CBlockIndex* pindexLast, bool fProofOfStake)
 {
-    CBigNum bnTargetLimit = bnProofOfWorkLimit;
-
-    if(fProofOfStake)
-    {
-        // Proof-of-Stake blocks has own target limit since nVersion=3 supermajority on mainNet and always on testNet
-        if(fTestNet || (pindexLast->nHeight + 1 > 15000))
-            bnTargetLimit = bnProofOfStakeLimit;
-        else if(pindexLast->nHeight + 1 > 14060)
-            bnTargetLimit = bnProofOfStakeHardLimit;
-    }
+    CBigNum bnTargetLimit = !fProofOfStake ? bnProofOfWorkLimit : GetProofOfStakeLimit(pindexLast->nHeight, pindexLast->nTime);
 
     if (pindexLast == NULL)
         return bnTargetLimit.GetCompact(); // genesis block
 
     const CBlockIndex* pindexPrev = GetLastBlockIndex(pindexLast, fProofOfStake);
     if (pindexPrev->pprev == NULL)
-        return bnInitialHashTarget.GetCompact(); // first block
+        return bnTargetLimit.GetCompact(); // first block
     const CBlockIndex* pindexPrevPrev = GetLastBlockIndex(pindexPrev->pprev, fProofOfStake);
     if (pindexPrevPrev->pprev == NULL)
-        return bnInitialHashTarget.GetCompact(); // second block
+        return bnTargetLimit.GetCompact(); // second block
 
     int64 nActualSpacing = pindexPrev->GetBlockTime() - pindexPrevPrev->GetBlockTime();
 
@@ -956,7 +1287,7 @@ unsigned int static GetNextTargetRequired(const CBlockIndex* pindexLast, bool fP
     // ppcoin: retarget with exponential moving toward target spacing
     CBigNum bnNew;
     bnNew.SetCompact(pindexPrev->nBits);
-    int64 nTargetSpacing = fProofOfStake? STAKE_TARGET_SPACING : min(nTargetSpacingWorkMax, (int64) STAKE_TARGET_SPACING * (1 + pindexLast->nHeight - pindexPrev->nHeight));
+    int64 nTargetSpacing = fProofOfStake? nStakeTargetSpacing : min(GetTargetSpacingWorkMax(pindexLast->nHeight, pindexLast->nTime), (int64) nStakeTargetSpacing * (1 + pindexLast->nHeight - pindexPrev->nHeight));
     int64 nInterval = nTargetTimespan / nTargetSpacing;
     bnNew *= ((nInterval - 1) * nTargetSpacing + nActualSpacing + nActualSpacing);
     bnNew /= ((nInterval + 1) * nTargetSpacing);
@@ -1006,171 +1337,107 @@ bool IsInitialBlockDownload()
 
 void static InvalidChainFound(CBlockIndex* pindexNew)
 {
-    if (pindexNew->bnChainTrust > bnBestInvalidTrust)
+    if (pindexNew->nChainTrust > nBestInvalidTrust)
     {
-        bnBestInvalidTrust = pindexNew->bnChainTrust;
-        CTxDB().WriteBestInvalidTrust(bnBestInvalidTrust);
-        MainFrameRepaint();
+        nBestInvalidTrust = pindexNew->nChainTrust;
+        pblocktree->WriteBestInvalidTrust(CBigNum(nBestInvalidTrust));
+        uiInterface.NotifyBlocksChanged();
     }
-    printf("InvalidChainFound: invalid block=%s  height=%d  trust=%s\n", pindexNew->GetBlockHash().ToString().substr(0,20).c_str(), pindexNew->nHeight, CBigNum(pindexNew->bnChainTrust).ToString().c_str());
-    printf("InvalidChainFound:  current best=%s  height=%d  trust=%s\n", hashBestChain.ToString().substr(0,20).c_str(), nBestHeight, CBigNum(bnBestChainTrust).ToString().c_str());
-    // ppcoin: should not enter safe mode for longer invalid chain
-}
 
-void CBlock::UpdateTime(const CBlockIndex* pindexPrev)
-{
-    nTime = max(GetBlockTime(), GetAdjustedTime());
+    uint256 nBestInvalidBlockTrust = pindexNew->nChainTrust - pindexNew->pprev->nChainTrust;
+    uint256 nBestBlockTrust = pindexBest->nHeight != 0 ? (pindexBest->nChainTrust - pindexBest->pprev->nChainTrust) : pindexBest->nChainTrust;
+
+    printf("InvalidChainFound: invalid block=%s  height=%d  trust=%s  blocktrust=%"PRI64d"  date=%s\n",
+      pindexNew->GetBlockHash().ToString().substr(0,20).c_str(), pindexNew->nHeight,
+      CBigNum(pindexNew->nChainTrust).ToString().c_str(), nBestInvalidBlockTrust.Get64(),
+      DateTimeStrFormat("%x %H:%M:%S", pindexNew->GetBlockTime()).c_str());
+    printf("InvalidChainFound:  current best=%s  height=%d  trust=%s  blocktrust=%"PRI64d"  date=%s\n",
+      hashBestChain.ToString().substr(0,20).c_str(), nBestHeight,
+      CBigNum(pindexBest->nChainTrust).ToString().c_str(),
+      nBestBlockTrust.Get64(),
+      DateTimeStrFormat("%x %H:%M:%S", pindexBest->GetBlockTime()).c_str());
 }
 
-
-
-
-
-
-
-
-
-
-
-bool CTransaction::DisconnectInputs(CTxDB& txdb)
-{
-    // Relinquish previous transactions' spent pointers
-    if (!IsCoinBase())
-    {
-        BOOST_FOREACH(const CTxIn& txin, vin)
-        {
-            COutPoint prevout = txin.prevout;
-
-            // Get prev txindex from disk
-            CTxIndex txindex;
-            if (!txdb.ReadTxIndex(prevout.hash, txindex))
-                return error("DisconnectInputs() : ReadTxIndex failed");
-
-            if (prevout.n >= txindex.vSpent.size())
-                return error("DisconnectInputs() : prevout.n out of range");
-
-            // Mark outpoint as not spent
-            txindex.vSpent[prevout.n].SetNull();
-
-            // Write back
-            if (!txdb.UpdateTxIndex(prevout.hash, txindex))
-                return error("DisconnectInputs() : UpdateTxIndex failed");
-        }
-    }
-
-    // Remove transaction from index
-    // This can fail if a duplicate of this transaction was in a chain that got
-    // reorganized away. This is only possible if this transaction was completely
-    // spent, so erasing it would be a no-op anway.
-    txdb.EraseTxIndex(*this);
-
-    return true;
+void static InvalidBlockFound(CBlockIndex *pindex) {
+    pindex->nStatus |= BLOCK_FAILED_VALID;
+    pblocktree->WriteBlockIndex(CDiskBlockIndex(pindex));
+    setBlockIndexValid.erase(pindex);
+    InvalidChainFound(pindex);
+    if (pindex->pnext)
+        ConnectBestBlock(); // reorganise away from the failed block
 }
 
+bool ConnectBestBlock() {
+    do {
+        CBlockIndex *pindexNewBest;
 
-bool CTransaction::FetchInputs(CTxDB& txdb, const map<uint256, CTxIndex>& mapTestPool,
-                               bool fBlock, bool fMiner, MapPrevTx& inputsRet, bool& fInvalid)
-{
-    // FetchInputs can return false either because we just haven't seen some inputs
-    // (in which case the transaction should be stored as an orphan)
-    // or because the transaction is malformed (in which case the transaction should
-    // be dropped).  If tx is definitely invalid, fInvalid will be set to true.
-    fInvalid = false;
-
-    if (IsCoinBase())
-        return true; // Coinbase transactions have no inputs to fetch.
-
-    for (unsigned int i = 0; i < vin.size(); i++)
-    {
-        COutPoint prevout = vin[i].prevout;
-        if (inputsRet.count(prevout.hash))
-            continue; // Got it already
-
-        // Read txindex
-        CTxIndex& txindex = inputsRet[prevout.hash].first;
-        bool fFound = true;
-        if ((fBlock || fMiner) && mapTestPool.count(prevout.hash))
-        {
-            // Get txindex from current proposed changes
-            txindex = mapTestPool.find(prevout.hash)->second;
-        }
-        else
         {
-            // Read txindex from txdb
-            fFound = txdb.ReadTxIndex(prevout.hash, txindex);
+            std::set<CBlockIndex*,CBlockIndexTrustComparator>::reverse_iterator it = setBlockIndexValid.rbegin();
+            if (it == setBlockIndexValid.rend())
+                return true;
+            pindexNewBest = *it;
         }
-        if (!fFound && (fBlock || fMiner))
-            return fMiner ? false : error("FetchInputs() : %s prev tx %s index entry not found", GetHash().ToString().substr(0,10).c_str(),  prevout.hash.ToString().substr(0,10).c_str());
 
-        // Read txPrev
-        CTransaction& txPrev = inputsRet[prevout.hash].second;
-        if (!fFound || txindex.pos == CDiskTxPos(1,1,1))
-        {
-            // Get prev tx from single transactions in memory
-            {
-                LOCK(mempool.cs);
-                if (!mempool.exists(prevout.hash))
-                    return error("FetchInputs() : %s mempool Tx prev not found %s", GetHash().ToString().substr(0,10).c_str(),  prevout.hash.ToString().substr(0,10).c_str());
-                txPrev = mempool.lookup(prevout.hash);
+        if (pindexNewBest == pindexBest)
+            return true; // nothing to do
+
+        // check ancestry
+        CBlockIndex *pindexTest = pindexNewBest;
+        std::vector<CBlockIndex*> vAttach;
+        do {
+            if (pindexTest->nStatus & BLOCK_FAILED_MASK) {
+                // mark descendants failed
+                CBlockIndex *pindexFailed = pindexNewBest;
+                while (pindexTest != pindexFailed) {
+                    pindexFailed->nStatus |= BLOCK_FAILED_CHILD;
+                    setBlockIndexValid.erase(pindexFailed);
+                    pblocktree->WriteBlockIndex(CDiskBlockIndex(pindexFailed));
+                    pindexFailed = pindexFailed->pprev;
+                }
+                InvalidChainFound(pindexNewBest);
+                break;
             }
-            if (!fFound)
-                txindex.vSpent.resize(txPrev.vout.size());
-        }
-        else
-        {
-            // Get prev tx from disk
-            if (!txPrev.ReadFromDisk(txindex.pos))
-                return error("FetchInputs() : %s ReadFromDisk prev tx %s failed", GetHash().ToString().substr(0,10).c_str(),  prevout.hash.ToString().substr(0,10).c_str());
-        }
-    }
 
-    // Make sure all prevout.n's are valid:
-    for (unsigned int i = 0; i < vin.size(); i++)
-    {
-        const COutPoint prevout = vin[i].prevout;
-        assert(inputsRet.count(prevout.hash) != 0);
-        const CTxIndex& txindex = inputsRet[prevout.hash].first;
-        const CTransaction& txPrev = inputsRet[prevout.hash].second;
-        if (prevout.n >= txPrev.vout.size() || prevout.n >= txindex.vSpent.size())
-        {
-            // Revisit this if/when transaction replacement is implemented and allows
-            // adding inputs:
-            fInvalid = true;
-            return DoS(100, error("FetchInputs() : %s prevout.n out of range %d %d %d prev tx %s\n%s", GetHash().ToString().substr(0,10).c_str(), prevout.n, txPrev.vout.size(), txindex.vSpent.size(), prevout.hash.ToString().substr(0,10).c_str(), txPrev.ToString().c_str()));
-        }
-    }
+            if (pindexBest == NULL || pindexTest->nChainTrust > pindexBest->nChainTrust)
+                vAttach.push_back(pindexTest);
 
-    return true;
+            if (pindexTest->pprev == NULL || pindexTest->pnext != NULL) {
+                reverse(vAttach.begin(), vAttach.end());
+                BOOST_FOREACH(CBlockIndex *pindexSwitch, vAttach)
+                    if (!SetBestChain(pindexSwitch))
+                        return false;
+                return true;
+            }
+            pindexTest = pindexTest->pprev;
+        } while(true);
+    } while(true);
 }
 
-const CTxOut& CTransaction::GetOutputFor(const CTxIn& input, const MapPrevTx& inputs) const
+void CBlock::UpdateTime(const CBlockIndex* pindexPrev)
 {
-    MapPrevTx::const_iterator mi = inputs.find(input.prevout.hash);
-    if (mi == inputs.end())
-        throw std::runtime_error("CTransaction::GetOutputFor() : prevout.hash not found");
-
-    const CTransaction& txPrev = (mi->second).second;
-    if (input.prevout.n >= txPrev.vout.size())
-        throw std::runtime_error("CTransaction::GetOutputFor() : prevout.n out of range");
+    nTime = max(GetBlockTime(), GetAdjustedTime());
+}
 
-    return txPrev.vout[input.prevout.n];
+const CTxOut &CTransaction::GetOutputFor(const CTxIn& input, CCoinsViewCache& view)
+{
+    const CCoins &coins = view.GetCoins(input.prevout.hash);
+    assert(coins.IsAvailable(input.prevout.n));
+    return coins.vout[input.prevout.n];
 }
 
-int64 CTransaction::GetValueIn(const MapPrevTx& inputs) const
+int64 CTransaction::GetValueIn(CCoinsViewCache& inputs) const
 {
     if (IsCoinBase())
         return 0;
 
     int64 nResult = 0;
     for (unsigned int i = 0; i < vin.size(); i++)
-    {
         nResult += GetOutputFor(vin[i], inputs).nValue;
-    }
-    return nResult;
 
+    return nResult;
 }
 
-unsigned int CTransaction::GetP2SHSigOpCount(const MapPrevTx& inputs) const
+unsigned int CTransaction::GetP2SHSigOpCount(CCoinsViewCache& inputs) const
 {
     if (IsCoinBase())
         return 0;
@@ -1178,119 +1445,146 @@ unsigned int CTransaction::GetP2SHSigOpCount(const MapPrevTx& inputs) const
     unsigned int nSigOps = 0;
     for (unsigned int i = 0; i < vin.size(); i++)
     {
-        const CTxOut& prevout = GetOutputFor(vin[i], inputs);
+        const CTxOut &prevout = GetOutputFor(vin[i], inputs);
         if (prevout.scriptPubKey.IsPayToScriptHash())
             nSigOps += prevout.scriptPubKey.GetSigOpCount(vin[i].scriptSig);
     }
     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 CTransaction::UpdateCoins(CCoinsViewCache &inputs, CTxUndo &txundo, int nHeight, unsigned int nTimeStamp, const uint256 &txhash) const
 {
-    // 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;
-        int64 nFees = 0;
-        for (unsigned int i = 0; i < vin.size(); i++)
-        {
-            COutPoint prevout = vin[i].prevout;
-            assert(inputs.count(prevout.hash) > 0);
-            CTxIndex& txindex = inputs[prevout.hash].first;
-            CTransaction& txPrev = inputs[prevout.hash].second;
-
-            if (prevout.n >= txPrev.vout.size() || prevout.n >= txindex.vSpent.size())
-                return DoS(100, error("ConnectInputs() : %s prevout.n out of range %d %d %d prev tx %s\n%s", GetHash().ToString().substr(0,10).c_str(), prevout.n, txPrev.vout.size(), txindex.vSpent.size(), prevout.hash.ToString().substr(0,10).c_str(), txPrev.ToString().c_str()));
+    // mark inputs spent
+    if (!IsCoinBase()) {
+        BOOST_FOREACH(const CTxIn &txin, vin) {
+            CCoins &coins = inputs.GetCoins(txin.prevout.hash);
+            if (coins.nTime > nTimeStamp)
+                return error("UpdateCoins() : timestamp violation");
+            CTxInUndo undo;
+            if (!coins.Spend(txin.prevout, undo))
+                return error("UpdateCoins() : cannot spend input");
+            txundo.vprevout.push_back(undo);
+        }
+    }
 
-            // If prev is coinbase/coinstake, check that it's matured
-            if (txPrev.IsCoinBase() || txPrev.IsCoinStake())
-                for (const CBlockIndex* pindex = pindexBlock; pindex && pindexBlock->nHeight - pindex->nHeight < nCoinbaseMaturity; pindex = pindex->pprev)
-                    if (pindex->nBlockPos == txindex.pos.nBlockPos && pindex->nFile == txindex.pos.nFile)
-                        return error("ConnectInputs() : tried to spend coinbase/coinstake at depth %d", pindexBlock->nHeight - pindex->nHeight);
+    // add outputs
+    if (!inputs.SetCoins(txhash, CCoins(*this, nHeight, nTimeStamp)))
+        return error("UpdateCoins() : cannot update output");
 
-            // ppcoin: check transaction timestamp
-            if (txPrev.nTime > nTime)
-                return DoS(100, error("ConnectInputs() : transaction timestamp earlier than input transaction"));
+    return true;
+}
 
-            // Check for negative or overflow input values
-            nValueIn += txPrev.vout[prevout.n].nValue;
-            if (!MoneyRange(txPrev.vout[prevout.n].nValue) || !MoneyRange(nValueIn))
-                return DoS(100, error("ConnectInputs() : txin values out of range"));
+bool CTransaction::HaveInputs(CCoinsViewCache &inputs) const
+{
+    if (!IsCoinBase()) { 
+        // first check whether information about the prevout hash is available
+        for (unsigned int i = 0; i < vin.size(); i++) {
+            const COutPoint &prevout = vin[i].prevout;
+            if (!inputs.HaveCoins(prevout.hash))
+                return false;
+        }
 
+        // then check whether the actual outputs are available
+        for (unsigned int i = 0; i < vin.size(); i++) {
+            const COutPoint &prevout = vin[i].prevout;
+            const CCoins &coins = inputs.GetCoins(prevout.hash);
+            if (!coins.IsAvailable(prevout.n))
+                return false;
         }
-        // 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.
+    }
+    return true;
+}
+
+bool CTransaction::CheckInputs(CCoinsViewCache &inputs, enum CheckSig_mode csmode, bool fStrictPayToScriptHash, bool fStrictEncodings, CBlock *pblock) const
+{
+    if (!IsCoinBase())
+    {
+        // This doesn't trigger the DoS code on purpose; if it did, it would make it easier
+        // for an attacker to attempt to split the network.
+        if (!HaveInputs(inputs))
+            return error("CheckInputs() : %s inputs unavailable", GetHash().ToString().substr(0,10).c_str());
+
+        CBlockIndex *pindexBlock = inputs.GetBestBlock();
+        int64 nValueIn = 0;
+        int64 nFees = 0;
         for (unsigned int i = 0; i < vin.size(); i++)
         {
-            COutPoint prevout = vin[i].prevout;
-            assert(inputs.count(prevout.hash) > 0);
-            CTxIndex& txindex = inputs[prevout.hash].first;
-            CTransaction& txPrev = inputs[prevout.hash].second;
-
-            // Check for conflicts (double-spend)
-            // This doesn't trigger the DoS code on purpose; if it did, it would make it easier
-            // for an attacker to attempt to split the network.
-            if (!txindex.vSpent[prevout.n].IsNull())
-                return fMiner ? false : error("ConnectInputs() : %s prev tx already used at %s", GetHash().ToString().substr(0,10).c_str(), txindex.vSpent[prevout.n].ToString().c_str());
-
-            // 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())))
-            {
-                // Verify signature
-                if (!VerifySignature(txPrev, *this, i, fStrictPayToScriptHash, 0))
-                {
-                    // 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());
+            const COutPoint &prevout = vin[i].prevout;
+            const CCoins &coins = inputs.GetCoins(prevout.hash);
 
-                    return DoS(100,error("ConnectInputs() : %s VerifySignature failed", GetHash().ToString().substr(0,10).c_str()));
-                }
+            // If prev is coinbase or coinstake, check that it's matured
+            if (coins.IsCoinBase() || coins.IsCoinStake()) {
+                if (pindexBlock->nHeight - coins.nHeight < nCoinbaseMaturity)
+                    return error("CheckInputs() : tried to spend %s at depth %d", coins.IsCoinBase() ? "coinbase" : "coinstake", pindexBlock->nHeight - coins.nHeight);
             }
 
-            // Mark outpoints as spent
-            txindex.vSpent[prevout.n] = posThisTx;
+            // Check transaction timestamp
+            if (coins.nTime > nTime)
+                return DoS(100, error("CheckInputs() : transaction timestamp earlier than input transaction"));
 
-            // Write back
-            if (fBlock || fMiner)
-            {
-                mapTestPool[prevout.hash] = txindex;
-            }
+            // Check for negative or overflow input values
+            nValueIn += coins.vout[prevout.n].nValue;
+            if (!MoneyRange(coins.vout[prevout.n].nValue) || !MoneyRange(nValueIn))
+                return DoS(100, error("CheckInputs() : txin values out of range"));
         }
 
         if (IsCoinStake())
         {
-            // ppcoin: coin stake tx earns reward instead of paying fee
+            if (!pblock)
+                return error("CheckInputs() : %s is a coinstake, but no block specified", GetHash().ToString().substr(0,10).c_str());
+
+            // Coin stake tx earns reward instead of paying fee
             uint64 nCoinAge;
-            if (!GetCoinAge(txdb, nCoinAge))
-                return error("ConnectInputs() : %s unable to get coin age for coinstake", GetHash().ToString().substr(0,10).c_str());
+            if (!GetCoinAge(nCoinAge))
+                return error("CheckInputs() : %s unable to get coin age for coinstake", GetHash().ToString().substr(0,10).c_str());
+
             int64 nStakeReward = GetValueOut() - nValueIn;
-            if (nStakeReward > GetProofOfStakeReward(nCoinAge) - GetMinFee() + MIN_TX_FEE)
-                return DoS(100, error("ConnectInputs() : %s stake reward exceeded", GetHash().ToString().substr(0,10).c_str()));
+            int64 nCalculatedStakeReward = GetProofOfStakeReward(nCoinAge, pblock->nBits, nTime) - GetMinFee() + MIN_TX_FEE;
+
+            if (nStakeReward > nCalculatedStakeReward)
+                return DoS(100, error("CheckInputs() : coinstake pays too much(actual=%"PRI64d" vs calculated=%"PRI64d")", nStakeReward, nCalculatedStakeReward));
         }
         else
         {
             if (nValueIn < GetValueOut())
-                return DoS(100, error("ConnectInputs() : %s value in < value out", GetHash().ToString().substr(0,10).c_str()));
+                return DoS(100, error("ChecktInputs() : %s value in < value out", GetHash().ToString().substr(0,10).c_str()));
 
             // Tally transaction fees
             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;
+                return DoS(100, error("CheckInputs() : %s nTxFee < 0", GetHash().ToString().substr(0,10).c_str()));
             nFees += nTxFee;
             if (!MoneyRange(nFees))
-                return DoS(100, error("ConnectInputs() : nFees out of range"));
+                return DoS(100, error("CheckInputs() : nFees out of range"));
+
+            // enforce transaction fees for every block until 1 May 2014 04:00:00 GMT
+            if (!fTestNet && nTxFee < GetMinFee() && nTime < OUTPUT_SWITCH_TIME)
+                return pblock? DoS(100, error("CheckInputs() : %s not paying required fee=%s, paid=%s", GetHash().ToString().substr(0,10).c_str(), FormatMoney(GetMinFee()).c_str(), FormatMoney(nTxFee).c_str())) : false;
+        }
+
+        // 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.
+
+        // Skip ECDSA signature verification when connecting blocks
+        // 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 (csmode == CS_ALWAYS || 
+            (csmode == CS_AFTER_CHECKPOINT && inputs.GetBestBlock()->nHeight >= Checkpoints::GetTotalBlocksEstimate())) {
+            for (unsigned int i = 0; i < vin.size(); i++) {
+                const COutPoint &prevout = vin[i].prevout;
+                const CCoins &coins = inputs.GetCoins(prevout.hash);
+
+                // Verify signature
+                if (!VerifySignature(coins, *this, i, fStrictPayToScriptHash, fStrictEncodings, 0)) {
+                    // only during transition phase for P2SH: do not invoke anti-DoS code for
+                    // potentially old clients relaying bad P2SH transactions
+                    if (fStrictPayToScriptHash && VerifySignature(coins, *this, i, false, fStrictEncodings, 0))
+                        return error("CheckInputs() : %s P2SH VerifySignature failed", GetHash().ToString().substr(0,10).c_str());
+
+                    return DoS(100,error("CheckInputs() : %s VerifySignature failed", GetHash().ToString().substr(0,10).c_str()));
+                }
+            }
         }
     }
 
@@ -1298,7 +1592,7 @@ bool CTransaction::ConnectInputs(CTxDB& txdb, MapPrevTx inputs,
 }
 
 
-bool CTransaction::ClientConnectInputs()
+bool CTransaction::ClientCheckInputs() const
 {
     if (IsCoinBase())
         return false;
@@ -1319,7 +1613,7 @@ bool CTransaction::ClientConnectInputs()
                 return false;
 
             // Verify signature
-            if (!VerifySignature(txPrev, *this, i, true, 0))
+            if (!VerifySignature(CCoins(txPrev, -1, -1), *this, i, true, false, 0))
                 return error("ConnectInputs() : VerifySignature failed");
 
             ///// this is redundant with the mempool.mapNextTx stuff,
@@ -1344,39 +1638,98 @@ bool CTransaction::ClientConnectInputs()
     return true;
 }
 
+bool CBlock::DisconnectBlock(CBlockIndex *pindex, CCoinsViewCache &view)
+{
+    assert(pindex == view.GetBestBlock());
 
+    CBlockUndo blockUndo;
+    {
+        CDiskBlockPos pos = pindex->GetUndoPos();
+        if (pos.IsNull())
+            return error("DisconnectBlock() : no undo data available");
+        FILE *file = OpenUndoFile(pos, true);
+        if (file == NULL)
+            return error("DisconnectBlock() : undo file not available");
+        CAutoFile fileUndo(file, SER_DISK, CLIENT_VERSION);
+        fileUndo >> blockUndo;
+    }
 
+    assert(blockUndo.vtxundo.size() + 1 == vtx.size());
 
-bool CBlock::DisconnectBlock(CTxDB& txdb, CBlockIndex* pindex)
-{
-    // Disconnect in reverse order
-    for (int i = vtx.size()-1; i >= 0; i--)
-        if (!vtx[i].DisconnectInputs(txdb))
-            return false;
+    // undo transactions in reverse order
+    for (int i = vtx.size() - 1; i >= 0; i--) {
+        const CTransaction &tx = vtx[i];
+        uint256 hash = tx.GetHash();
 
-    // Update block index on disk without changing it in memory.
-    // The memory index structure will be changed after the db commits.
-    if (pindex->pprev)
-    {
-        CDiskBlockIndex blockindexPrev(pindex->pprev);
-        blockindexPrev.hashNext = 0;
-        if (!txdb.WriteBlockIndex(blockindexPrev))
-            return error("DisconnectBlock() : WriteBlockIndex failed");
+        // don't check coinbase coins for proof-of-stake block
+        if(IsProofOfStake() && tx.IsCoinBase())
+            continue;
+
+        // check that all outputs are available
+        if (!view.HaveCoins(hash))
+            return error("DisconnectBlock() : outputs still spent? database corrupted");
+        CCoins &outs = view.GetCoins(hash);
+
+        CCoins outsBlock = CCoins(tx, pindex->nHeight, pindex->nTime);
+        if (outs != outsBlock)
+            return error("DisconnectBlock() : added transaction mismatch? database corrupted");
+
+        // remove outputs
+        outs = CCoins();
+
+        // restore inputs
+        if (i > 0) { // not coinbases
+            const CTxUndo &txundo = blockUndo.vtxundo[i-1];
+            assert(txundo.vprevout.size() == tx.vin.size());
+            for (unsigned int j = tx.vin.size(); j-- > 0;) {
+                const COutPoint &out = tx.vin[j].prevout;
+                const CTxInUndo &undo = txundo.vprevout[j];
+                CCoins coins;
+                view.GetCoins(out.hash, coins); // this can fail if the prevout was already entirely spent
+                if (coins.IsPruned()) {
+                    if (undo.nHeight == 0)
+                        return error("DisconnectBlock() : undo data doesn't contain tx metadata? database corrupted");
+                    coins.fCoinBase = undo.fCoinBase;
+                    coins.fCoinStake = undo.fCoinStake;
+                    coins.nHeight = undo.nHeight;
+                    coins.nTime = undo.nTime;
+                    coins.nBlockTime = undo.nBlockTime;
+                    coins.nVersion = undo.nVersion;
+                } else {
+                    if (undo.nHeight != 0)
+                        return error("DisconnectBlock() : undo data contains unneeded tx metadata? database corrupted");
+                }
+                if (coins.IsAvailable(out.n))
+                    return error("DisconnectBlock() : prevout output not spent? database corrupted");
+                if (coins.vout.size() < out.n+1)
+                    coins.vout.resize(out.n+1);
+                coins.vout[out.n] = undo.txout;
+                if (!view.SetCoins(out.hash, coins))
+                    return error("DisconnectBlock() : cannot restore coin inputs");
+            }
+        }
+
+        // clean up wallet after disconnecting coinstake
+        SyncWithWallets(vtx[i].GetHash(), vtx[i], this, false, false);
     }
 
-    // ppcoin: clean up wallet after disconnecting coinstake
-    BOOST_FOREACH(CTransaction& tx, vtx)
-        SyncWithWallets(tx, this, false, false);
+    // move best block pointer to prevout block
+    view.SetBestBlock(pindex->pprev);
 
     return true;
 }
 
-bool CBlock::ConnectBlock(CTxDB& txdb, CBlockIndex* pindex)
+bool FindUndoPos(int nFile, CDiskBlockPos &pos, unsigned int nAddSize);
+
+bool CBlock::ConnectBlock(CBlockIndex* pindex, CCoinsViewCache &view, bool fJustCheck)
 {
     // Check it again in case a previous version let a bad block in
-    if (!CheckBlock())
+    if (!CheckBlock(!fJustCheck, !fJustCheck))
         return false;
 
+    // verify that the view's current state corresponds to the previous block
+    assert(pindex->pprev == view.GetBestBlock());
+
     // 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
@@ -1384,179 +1737,216 @@ bool CBlock::ConnectBlock(CTxDB& txdb, CBlockIndex* pindex)
     // being sent to another address.
     // See BIP30 and http://r6.ca/blog/20120206T005236Z.html for more information.
     // This logic is not necessary for memory pool transactions, as AcceptToMemoryPool
-    // already refuses previously-known transaction id's entirely.
-    BOOST_FOREACH(CTransaction& tx, vtx)
-    {
-        CTxIndex txindexOld;
-        if (txdb.ReadTxIndex(tx.GetHash(), txindexOld))
-        {
-            BOOST_FOREACH(CDiskTxPos &pos, txindexOld.vSpent)
-                if (pos.IsNull())
-                    return false;
+    // already refuses previously-known transaction ids entirely.
+    // This rule was originally applied all blocks whose timestamp was after March 15, 2012, 0:00 UTC.
+    // Now that the whole chain is irreversibly beyond that time it is applied to all blocks except the
+    // two in the chain that violate it. This prevents exploiting the issue against nodes in their
+    // initial block download.
+    bool fEnforceBIP30 = true;
+
+    if (fEnforceBIP30) {
+        for (unsigned int i=0; i<vtx.size(); i++) {
+            uint256 hash = GetTxHash(i);
+            if (view.HaveCoins(hash) && !view.GetCoins(hash).IsPruned())
+                return error("ConnectBlock() : tried to overwrite transaction");
         }
     }
 
     // BIP16 always active
     bool fStrictPayToScriptHash = true;
 
-    //// issue here: it doesn't know the version
-    unsigned int nTxPos = pindex->nBlockPos + ::GetSerializeSize(CBlock(), SER_DISK, CLIENT_VERSION) - (2 * GetSizeOfCompactSize(0)) + GetSizeOfCompactSize(vtx.size());
+    CBlockUndo blockundo;
 
-    map<uint256, CTxIndex> mapQueuedChanges;
-    int64 nFees = 0;
-    int64 nValueIn = 0;
-    int64 nValueOut = 0;
+    int64 nFees = 0, nValueIn = 0, nValueOut = 0;
     unsigned int nSigOps = 0;
-    BOOST_FOREACH(CTransaction& tx, vtx)
+    for (unsigned int i=0; i<vtx.size(); i++)
     {
+        const CTransaction &tx = vtx[i];
         nSigOps += tx.GetLegacySigOpCount();
         if (nSigOps > MAX_BLOCK_SIGOPS)
             return DoS(100, error("ConnectBlock() : too many sigops"));
 
-        CDiskTxPos posThisTx(pindex->nFile, pindex->nBlockPos, nTxPos);
-        nTxPos += ::GetSerializeSize(tx, SER_DISK, CLIENT_VERSION);
-
-        MapPrevTx mapInputs;
-        if (tx.IsCoinBase())
-            nValueOut += tx.GetValueOut();
-        else
+        if (!tx.IsCoinBase())
         {
-            bool fInvalid;
-            if (!tx.FetchInputs(txdb, mapQueuedChanges, true, false, mapInputs, fInvalid))
-                return false;
+            if (!tx.HaveInputs(view))
+                return DoS(100, error("ConnectBlock() : inputs missing/spent"));
 
             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);
+                nSigOps += tx.GetP2SHSigOpCount(view);
                 if (nSigOps > MAX_BLOCK_SIGOPS)
-                    return DoS(100, error("ConnectBlock() : too many sigops"));
+                     return DoS(100, error("ConnectBlock() : too many sigops"));
             }
 
-            int64 nTxValueIn = tx.GetValueIn(mapInputs);
             int64 nTxValueOut = tx.GetValueOut();
+            int64 nTxValueIn  = tx.GetValueIn(view);
+
             nValueIn += nTxValueIn;
             nValueOut += nTxValueOut;
+
             if (!tx.IsCoinStake())
                 nFees += nTxValueIn - nTxValueOut;
 
-            if (!tx.ConnectInputs(txdb, mapInputs, mapQueuedChanges, posThisTx, pindex, true, false, fStrictPayToScriptHash))
+            if (!tx.CheckInputs(view, CS_AFTER_CHECKPOINT, fStrictPayToScriptHash, false, this))
                 return false;
         }
+        else
+        {
+            nValueOut += tx.GetValueOut();
+        }
 
-        mapQueuedChanges[tx.GetHash()] = CTxIndex(posThisTx, tx.vout.size());
+        // don't create coinbase coins for proof-of-stake block
+        if(IsProofOfStake() && tx.IsCoinBase())
+            continue;
+
+        CTxUndo txundo;
+        if (!tx.UpdateCoins(view, txundo, pindex->nHeight, pindex->nTime, GetTxHash(i)))
+            return error("ConnectBlock() : UpdateInputs failed");
+        if (!tx.IsCoinBase())
+            blockundo.vtxundo.push_back(txundo);
     }
 
-    // ppcoin: 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");
 
-    // Write queued txindex changes
-    for (map<uint256, CTxIndex>::iterator mi = mapQueuedChanges.begin(); mi != mapQueuedChanges.end(); ++mi)
+    if (fJustCheck)
+        return true;
+
+    // Write undo information to disk
+    if (pindex->GetUndoPos().IsNull() || (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_SCRIPTS)
     {
-        if (!txdb.UpdateTxIndex((*mi).first, (*mi).second))
-            return error("ConnectBlock() : UpdateTxIndex failed");
+        if (pindex->GetUndoPos().IsNull()) {
+            CDiskBlockPos pos;
+            if (!FindUndoPos(pindex->nFile, pos, ::GetSerializeSize(blockundo, SER_DISK, CLIENT_VERSION) + 8))
+                return error("ConnectBlock() : FindUndoPos failed");
+            if (!blockundo.WriteToDisk(pos))
+                return error("ConnectBlock() : CBlockUndo::WriteToDisk failed");
+
+            // update nUndoPos in block index
+            pindex->nUndoPos = pos.nPos;
+            pindex->nStatus |= BLOCK_HAVE_UNDO;
+        }
+
+        pindex->nStatus = (pindex->nStatus & ~BLOCK_VALID_MASK) | BLOCK_VALID_SCRIPTS;
+
+        CDiskBlockIndex blockindex(pindex);
+        if (!pblocktree->WriteBlockIndex(blockindex))
+            return error("ConnectBlock() : WriteBlockIndex failed");
     }
 
-    // ppcoin: fees are not collected by miners as in bitcoin
-    // ppcoin: fees are destroyed to compensate the entire network
+    // add this block to the view's blockchain
+    if (!view.SetBestBlock(pindex))
+        return false;
+
+    // fees are destroyed to compensate the entire network
     if (fDebug && GetBoolArg("-printcreation"))
         printf("ConnectBlock() : destroy=%s nFees=%"PRI64d"\n", FormatMoney(nFees).c_str(), nFees);
 
-    // Update block index on disk without changing it in memory.
-    // The memory index structure will be changed after the db commits.
-    if (pindex->pprev)
-    {
-        CDiskBlockIndex blockindexPrev(pindex->pprev);
-        blockindexPrev.hashNext = pindex->GetBlockHash();
-        if (!txdb.WriteBlockIndex(blockindexPrev))
-            return error("ConnectBlock() : WriteBlockIndex for blockindexPrev failed");
-    }
-
     // Watch for transactions paying to me
-    BOOST_FOREACH(CTransaction& tx, vtx)
-        SyncWithWallets(tx, this, true);
+    for (unsigned int i=0; i<vtx.size(); i++)
+        SyncWithWallets(GetTxHash(i), vtx[i], this, true);
 
     return true;
 }
 
-bool Reorganize(CTxDB& txdb, CBlockIndex* pindexNew)
+bool SetBestChain(CBlockIndex* pindexNew)
 {
-    printf("REORGANIZE\n");
+    CCoinsViewCache &view = *pcoinsTip;
+
+    // special case for attaching the genesis block
+    // note that no ConnectBlock is called, so its coinbase output is non-spendable
+    if (pindexGenesisBlock == NULL && pindexNew->GetBlockHash() == (!fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet))
+    {
+        view.SetBestBlock(pindexNew);
+        if (!view.Flush())
+            return false;
+        pindexGenesisBlock = pindexNew;
+        pindexBest = pindexNew;
+        hashBestChain = pindexNew->GetBlockHash();
+        nBestHeight = pindexBest->nHeight;
+        nBestChainTrust = pindexNew->nChainTrust;
+        return true;
+    }
 
-    // Find the fork
-    CBlockIndex* pfork = pindexBest;
+    // Find the fork (typically, there is none)
+    CBlockIndex* pfork = view.GetBestBlock();
     CBlockIndex* plonger = pindexNew;
     while (pfork != plonger)
     {
         while (plonger->nHeight > pfork->nHeight)
             if (!(plonger = plonger->pprev))
-                return error("Reorganize() : plonger->pprev is null");
+                return error("SetBestChain() : plonger->pprev is null");
         if (pfork == plonger)
             break;
         if (!(pfork = pfork->pprev))
-            return error("Reorganize() : pfork->pprev is null");
+            return error("SetBestChain() : pfork->pprev is null");
     }
 
-    // List of what to disconnect
+    // List of what to disconnect (typically nothing)
     vector<CBlockIndex*> vDisconnect;
-    for (CBlockIndex* pindex = pindexBest; pindex != pfork; pindex = pindex->pprev)
+    for (CBlockIndex* pindex = view.GetBestBlock(); pindex != pfork; pindex = pindex->pprev)
         vDisconnect.push_back(pindex);
 
-    // List of what to connect
+    // List of what to connect (typically only pindexNew)
     vector<CBlockIndex*> vConnect;
     for (CBlockIndex* pindex = pindexNew; pindex != pfork; pindex = pindex->pprev)
         vConnect.push_back(pindex);
     reverse(vConnect.begin(), vConnect.end());
 
-    printf("REORGANIZE: Disconnect %i blocks; %s..%s\n", vDisconnect.size(), pfork->GetBlockHash().ToString().substr(0,20).c_str(), pindexBest->GetBlockHash().ToString().substr(0,20).c_str());
-    printf("REORGANIZE: Connect %i blocks; %s..%s\n", vConnect.size(), pfork->GetBlockHash().ToString().substr(0,20).c_str(), pindexNew->GetBlockHash().ToString().substr(0,20).c_str());
+    if (vDisconnect.size() > 0) {
+        printf("REORGANIZE: Disconnect %"PRIszu" blocks; %s..%s\n", vDisconnect.size(), pfork->GetBlockHash().ToString().substr(0,20).c_str(), pindexBest->GetBlockHash().ToString().substr(0,20).c_str());
+        printf("REORGANIZE: Connect %"PRIszu" blocks; %s..%s\n", vConnect.size(), pfork->GetBlockHash().ToString().substr(0,20).c_str(), pindexNew->GetBlockHash().ToString().substr(0,20).c_str());
+    }
 
     // Disconnect shorter branch
     vector<CTransaction> vResurrect;
-    BOOST_FOREACH(CBlockIndex* pindex, vDisconnect)
-    {
+    BOOST_FOREACH(CBlockIndex* pindex, vDisconnect) {
         CBlock block;
         if (!block.ReadFromDisk(pindex))
-            return error("Reorganize() : ReadFromDisk for disconnect failed");
-        if (!block.DisconnectBlock(txdb, pindex))
-            return error("Reorganize() : DisconnectBlock %s failed", pindex->GetBlockHash().ToString().substr(0,20).c_str());
+            return error("SetBestChain() : ReadFromDisk for disconnect failed");
+        CCoinsViewCache viewTemp(view, true);
+        if (!block.DisconnectBlock(pindex, viewTemp))
+            return error("SetBestChain() : DisconnectBlock %s failed", pindex->GetBlockHash().ToString().substr(0,20).c_str());
+        if (!viewTemp.Flush())
+            return error("SetBestChain() : Cache flush failed after disconnect");
 
         // Queue memory transactions to resurrect
         BOOST_FOREACH(const CTransaction& tx, block.vtx)
-            if (!(tx.IsCoinBase() || tx.IsCoinStake()))
+            if (!tx.IsCoinBase() && !tx.IsCoinStake())
                 vResurrect.push_back(tx);
     }
 
     // Connect longer branch
     vector<CTransaction> vDelete;
-    for (unsigned int i = 0; i < vConnect.size(); i++)
-    {
-        CBlockIndex* pindex = vConnect[i];
+    BOOST_FOREACH(CBlockIndex *pindex, vConnect) {
         CBlock block;
         if (!block.ReadFromDisk(pindex))
-            return error("Reorganize() : ReadFromDisk for connect failed");
-        if (!block.ConnectBlock(txdb, pindex))
-        {
-            // Invalid block
-            txdb.TxnAbort();
-            return error("Reorganize() : ConnectBlock %s failed", pindex->GetBlockHash().ToString().substr(0,20).c_str());
+            return error("SetBestChain() : ReadFromDisk for connect failed");
+        CCoinsViewCache viewTemp(view, true);
+        if (!block.ConnectBlock(pindex, viewTemp)) {
+            InvalidChainFound(pindexNew);
+            InvalidBlockFound(pindex);
+            return error("SetBestChain() : ConnectBlock %s failed", pindex->GetBlockHash().ToString().substr(0,20).c_str());
         }
+        if (!viewTemp.Flush())
+            return error("SetBestChain() : Cache flush failed after connect");
 
         // Queue memory transactions to delete
         BOOST_FOREACH(const CTransaction& tx, block.vtx)
             vDelete.push_back(tx);
     }
-    if (!txdb.WriteHashBestChain(pindexNew->GetBlockHash()))
-        return error("Reorganize() : WriteHashBestChain failed");
 
     // Make sure it's successfully written to disk before changing memory structure
-    if (!txdb.TxnCommit())
-        return error("Reorganize() : TxnCommit failed");
+    bool fIsInitialDownload = IsInitialBlockDownload();
+    if (!fIsInitialDownload || view.GetCacheSize()>5000)
+        if (!view.Flush())
+            return false;
+
+    // At this point, all changes have been done to the database.
+    // Proceed by updating the memory structures.
 
     // Disconnect shorter branch
     BOOST_FOREACH(CBlockIndex* pindex, vDisconnect)
@@ -1570,118 +1960,13 @@ bool Reorganize(CTxDB& txdb, CBlockIndex* pindexNew)
 
     // Resurrect memory transactions that were in the disconnected branch
     BOOST_FOREACH(CTransaction& tx, vResurrect)
-        tx.AcceptToMemoryPool(txdb, false);
+        tx.AcceptToMemoryPool(false);
 
     // Delete redundant memory transactions that are in the connected branch
     BOOST_FOREACH(CTransaction& tx, vDelete)
         mempool.remove(tx);
 
-    printf("REORGANIZE: done\n");
-
-    return true;
-}
-
-
-static void
-runCommand(std::string strCommand)
-{
-    int nErr = ::system(strCommand.c_str());
-    if (nErr)
-        printf("runCommand error: system(%s) returned %d\n", strCommand.c_str(), nErr);
-}
-
-// Called from inside SetBestChain: attaches a block to the new best chain being built
-bool CBlock::SetBestChainInner(CTxDB& txdb, CBlockIndex *pindexNew)
-{
-    uint256 hash = GetHash();
-
-    // Adding to current best branch
-    if (!ConnectBlock(txdb, pindexNew) || !txdb.WriteHashBestChain(hash))
-    {
-        txdb.TxnAbort();
-        InvalidChainFound(pindexNew);
-        return false;
-    }
-    if (!txdb.TxnCommit())
-        return error("SetBestChain() : TxnCommit failed");
-
-    // Add to current best branch
-    pindexNew->pprev->pnext = pindexNew;
-
-    // Delete redundant memory transactions
-    BOOST_FOREACH(CTransaction& tx, vtx)
-        mempool.remove(tx);
-
-    return true;
-}
-
-bool CBlock::SetBestChain(CTxDB& txdb, CBlockIndex* pindexNew)
-{
-    uint256 hash = GetHash();
-
-    if (!txdb.TxnBegin())
-        return error("SetBestChain() : TxnBegin failed");
-
-    if (pindexGenesisBlock == NULL && hash == hashGenesisBlock)
-    {
-        txdb.WriteHashBestChain(hash);
-        if (!txdb.TxnCommit())
-            return error("SetBestChain() : TxnCommit failed");
-        pindexGenesisBlock = pindexNew;
-    }
-    else if (hashPrevBlock == hashBestChain)
-    {
-        if (!SetBestChainInner(txdb, pindexNew))
-            return error("SetBestChain() : SetBestChainInner failed");
-    }
-    else
-    {
-        // the first block in the new chain that will cause it to become the new best chain
-        CBlockIndex *pindexIntermediate = pindexNew;
-
-        // list of blocks that need to be connected afterwards
-        std::vector<CBlockIndex*> vpindexSecondary;
-
-        // Reorganize is costly in terms of db load, as it works in a single db transaction.
-        // Try to limit how much needs to be done inside
-        while (pindexIntermediate->pprev && pindexIntermediate->pprev->bnChainTrust > pindexBest->bnChainTrust)
-        {
-            vpindexSecondary.push_back(pindexIntermediate);
-            pindexIntermediate = pindexIntermediate->pprev;
-        }
-
-        if (!vpindexSecondary.empty())
-            printf("Postponing %i reconnects\n", vpindexSecondary.size());
-
-        // Switch to new best branch
-        if (!Reorganize(txdb, pindexIntermediate))
-        {
-            txdb.TxnAbort();
-            InvalidChainFound(pindexNew);
-            return error("SetBestChain() : Reorganize failed");
-        }
-
-        // Connect futher blocks
-        BOOST_REVERSE_FOREACH(CBlockIndex *pindex, vpindexSecondary)
-        {
-            CBlock block;
-            if (!block.ReadFromDisk(pindex))
-            {
-                printf("SetBestChain() : ReadFromDisk failed\n");
-                break;
-            }
-            if (!txdb.TxnBegin()) {
-                printf("SetBestChain() : TxnBegin 2 failed\n");
-                break;
-            }
-            // errors now are not fatal, we still did a reorganisation to a new chain in a valid way
-            if (!block.SetBestChainInner(txdb, pindex))
-                break;
-        }
-    }
-
     // Update best block in wallet (so we can detect restored wallets)
-    bool fIsInitialDownload = IsInitialBlockDownload();
     if (!fIsInitialDownload)
     {
         const CBlockLocator locator(pindexNew);
@@ -1689,13 +1974,37 @@ bool CBlock::SetBestChain(CTxDB& txdb, CBlockIndex* pindexNew)
     }
 
     // New best block
-    hashBestChain = hash;
+    hashBestChain = pindexNew->GetBlockHash();
     pindexBest = pindexNew;
+    pblockindexFBBHLast = NULL;
     nBestHeight = pindexBest->nHeight;
-    bnBestChainTrust = pindexNew->bnChainTrust;
+    nBestChainTrust = pindexNew->nChainTrust;
     nTimeBestReceived = GetTime();
     nTransactionsUpdated++;
-    printf("SetBestChain: new best=%s  height=%d  trust=%s  moneysupply=%s\n", hashBestChain.ToString().substr(0,20).c_str(), nBestHeight, bnBestChainTrust.ToString().c_str(), FormatMoney(pindexBest->nMoneySupply).c_str());
+
+    uint256 nBestBlockTrust = pindexBest->nHeight != 0 ? (pindexBest->nChainTrust - pindexBest->pprev->nChainTrust) : pindexBest->nChainTrust;
+
+    printf("SetBestChain: new best=%s  height=%d  trust=%s blocktrust=%s  tx=%lu  date=%s\n",
+      hashBestChain.ToString().substr(0,20).c_str(), nBestHeight, CBigNum(nBestChainTrust).ToString().c_str(), CBigNum(nBestBlockTrust).ToString().c_str(), (unsigned long)pindexNew->nChainTx,
+      DateTimeStrFormat("%x %H:%M:%S", pindexBest->GetBlockTime()).c_str());
+
+    // Check the version of the last 100 blocks to see if we need to upgrade:
+    if (!fIsInitialDownload)
+    {
+        int nUpgraded = 0;
+        const CBlockIndex* pindex = pindexBest;
+        for (int i = 0; i < 100 && pindex != NULL; i++)
+        {
+            if (pindex->nVersion > CBlock::CURRENT_VERSION)
+                ++nUpgraded;
+            pindex = pindex->pprev;
+        }
+        if (nUpgraded > 0)
+            printf("SetBestChain: %d of last 100 blocks above version %d\n", nUpgraded, CBlock::CURRENT_VERSION);
+        if (nUpgraded > 100/2)
+            // strMiscWarning is read by GetWarnings(), called by Qt and the JSON-RPC code to warn the user:
+            strMiscWarning = _("Warning: This version is obsolete, upgrade required!");
+    }
 
     std::string strCmd = GetArg("-blocknotify", "");
 
@@ -1708,44 +2017,39 @@ bool CBlock::SetBestChain(CTxDB& txdb, CBlockIndex* pindexNew)
     return true;
 }
 
-
-// ppcoin: total coin age spent in transaction, in the unit of coin-days.
+// Total coin age spent in transaction, in the unit of coin-days.
 // Only those coins meeting minimum age requirement counts. As those
 // transactions not in main chain are not currently indexed so we
 // might not find out about their coin age. Older transactions are 
 // guaranteed to be in main chain by sync-checkpoint. This rule is
 // introduced to help nodes establish a consistent view of the coin
 // age (trust score) of competing branches.
-bool CTransaction::GetCoinAge(CTxDB& txdb, uint64& nCoinAge) const
+bool CTransaction::GetCoinAge(uint64& nCoinAge) const
 {
+    CCoinsViewCache &inputs = *pcoinsTip;
+
     CBigNum bnCentSecond = 0;  // coin age in the unit of cent-seconds
     nCoinAge = 0;
 
     if (IsCoinBase())
         return true;
 
-    BOOST_FOREACH(const CTxIn& txin, vin)
+    for (unsigned int i = 0; i < vin.size(); i++)
     {
-        // First try finding the previous transaction in database
-        CTransaction txPrev;
-        CTxIndex txindex;
-        if (!txPrev.ReadFromDisk(txdb, txin.prevout, txindex))
-            continue;  // previous transaction not in main chain
-        if (nTime < txPrev.nTime)
-            return false;  // Transaction timestamp violation
+        const COutPoint &prevout = vin[i].prevout;
+        CCoins coins;
+        if (!inputs.GetCoins(prevout.hash, coins))
+            continue;
 
-        // Read block header
-        CBlock block;
-        if (!block.ReadFromDisk(txindex.pos.nFile, txindex.pos.nBlockPos, false))
-            return false; // unable to read block of previous transaction
-        if (block.GetBlockTime() + nStakeMinAge > nTime)
-            continue; // only count coins meeting min age requirement
+        if (nTime < coins.nTime)
+            return false;  // Transaction timestamp violation
 
-        int64 nValueIn = txPrev.vout[txin.prevout.n].nValue;
-        bnCentSecond += CBigNum(nValueIn) * (nTime-txPrev.nTime) / CENT;
+        // only count coins meeting min age requirement
+        if (coins.nBlockTime + nStakeMinAge > nTime)
+            continue;
 
-        if (fDebug && GetBoolArg("-printcoinage"))
-            printf("coin age nValueIn=%-12I64d nTimeDiff=%d bnCentSecond=%s\n", nValueIn, nTime - txPrev.nTime, bnCentSecond.ToString().c_str());
+        int64 nValueIn = coins.vout[vin[i].prevout.n].nValue;
+        bnCentSecond += CBigNum(nValueIn) * (nTime-coins.nTime) / CENT;
     }
 
     CBigNum bnCoinDay = bnCentSecond * CENT / COIN / (24 * 60 * 60);
@@ -1755,16 +2059,15 @@ bool CTransaction::GetCoinAge(CTxDB& txdb, uint64& nCoinAge) const
     return true;
 }
 
-// ppcoin: total coin age spent in block, in the unit of coin-days.
+// Total coin age spent in block, in the unit of coin-days.
 bool CBlock::GetCoinAge(uint64& nCoinAge) const
 {
     nCoinAge = 0;
 
-    CTxDB txdb("r");
     BOOST_FOREACH(const CTransaction& tx, vtx)
     {
         uint64 nTxCoinAge;
-        if (tx.GetCoinAge(txdb, nTxCoinAge))
+        if (tx.GetCoinAge(nTxCoinAge))
             nCoinAge += nTxCoinAge;
         else
             return false;
@@ -1777,8 +2080,7 @@ bool CBlock::GetCoinAge(uint64& nCoinAge) const
     return true;
 }
 
-
-bool CBlock::AddToBlockIndex(unsigned int nFile, unsigned int nBlockPos)
+bool CBlock::AddToBlockIndex(const CDiskBlockPos &pos)
 {
     // Check for duplicate
     uint256 hash = GetHash();
@@ -1786,26 +2088,30 @@ bool CBlock::AddToBlockIndex(unsigned int nFile, unsigned int nBlockPos)
         return error("AddToBlockIndex() : %s already exists", hash.ToString().substr(0,20).c_str());
 
     // Construct new block index object
-    CBlockIndex* pindexNew = new CBlockIndex(nFile, nBlockPos, *this);
+    CBlockIndex* pindexNew = new CBlockIndex(*this);
     if (!pindexNew)
         return error("AddToBlockIndex() : new CBlockIndex failed");
-
-    pindexNew->phashBlock = &hash;
+    map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.insert(make_pair(hash, pindexNew)).first;
+    pindexNew->phashBlock = &((*mi).first);
     map<uint256, CBlockIndex*>::iterator miPrev = mapBlockIndex.find(hashPrevBlock);
     if (miPrev != mapBlockIndex.end())
     {
         pindexNew->pprev = (*miPrev).second;
         pindexNew->nHeight = pindexNew->pprev->nHeight + 1;
     }
-
-    // ppcoin: compute chain trust score
-    pindexNew->bnChainTrust = (pindexNew->pprev ? pindexNew->pprev->bnChainTrust : 0) + pindexNew->GetBlockTrust();
-
-    // ppcoin: compute stake entropy bit for stake modifier
-    if (!pindexNew->SetStakeEntropyBit(GetStakeEntropyBit(pindexNew->nHeight)))
+    pindexNew->nTx = vtx.size();
+    pindexNew->nChainTrust = (pindexNew->pprev ? pindexNew->pprev->nChainTrust : 0) + pindexNew->GetBlockTrust();
+    pindexNew->nChainTx = (pindexNew->pprev ? pindexNew->pprev->nChainTx : 0) + pindexNew->nTx;
+    pindexNew->nFile = pos.nFile;
+    pindexNew->nDataPos = pos.nPos;
+    pindexNew->nUndoPos = 0;
+    pindexNew->nStatus = BLOCK_VALID_TRANSACTIONS | BLOCK_HAVE_DATA;
+
+    // Compute stake entropy bit for stake modifier
+    if (!pindexNew->SetStakeEntropyBit(GetStakeEntropyBit(pindexNew->nTime)))
         return error("AddToBlockIndex() : SetStakeEntropyBit() failed");
 
-    // ppcoin: record proof-of-stake hash value
+    // Record proof-of-stake hash value
     if (pindexNew->IsProofOfStake())
     {
         if (!mapProofOfStake.count(hash))
@@ -1813,7 +2119,7 @@ bool CBlock::AddToBlockIndex(unsigned int nFile, unsigned int nBlockPos)
         pindexNew->hashProofOfStake = mapProofOfStake[hash];
     }
 
-    // ppcoin: compute stake modifier
+    // Compute stake modifier
     uint64 nStakeModifier = 0;
     bool fGeneratedStakeModifier = false;
     if (!ComputeNextStakeModifier(pindexNew->pprev, nStakeModifier, fGeneratedStakeModifier))
@@ -1823,43 +2129,109 @@ bool CBlock::AddToBlockIndex(unsigned int nFile, unsigned int nBlockPos)
     if (!CheckStakeModifierCheckpoints(pindexNew->nHeight, pindexNew->nStakeModifierChecksum))
         return error("AddToBlockIndex() : Rejected by stake modifier checkpoint height=%d, modifier=0x%016"PRI64x, pindexNew->nHeight, nStakeModifier);
 
-    // Add to mapBlockIndex
-    map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.insert(make_pair(hash, pindexNew)).first;
-    if (pindexNew->IsProofOfStake())
-        setStakeSeen.insert(make_pair(pindexNew->prevoutStake, pindexNew->nStakeTime));
-    pindexNew->phashBlock = &((*mi).first);
+    setBlockIndexValid.insert(pindexNew);
 
-    // Write to disk block index
-    CTxDB txdb;
-    if (!txdb.TxnBegin())
-        return false;
-    txdb.WriteBlockIndex(CDiskBlockIndex(pindexNew));
-    if (!txdb.TxnCommit())
-        return false;
-
-    // New best
-    if (pindexNew->bnChainTrust > bnBestChainTrust)
-        if (!SetBestChain(txdb, pindexNew))
-            return false;
+    pblocktree->WriteBlockIndex(CDiskBlockIndex(pindexNew));
 
-    txdb.Close();
+    // New best?
+    if (!ConnectBestBlock())
+        return false;
 
     if (pindexNew == pindexBest)
     {
         // Notify UI to display prev block's coinbase if it was ours
         static uint256 hashPrevBestCoinBase;
         UpdatedTransaction(hashPrevBestCoinBase);
-        hashPrevBestCoinBase = vtx[0].GetHash();
+        hashPrevBestCoinBase = GetTxHash(0);
     }
 
-    MainFrameRepaint();
+    pblocktree->Flush();
+
+    uiInterface.NotifyBlocksChanged();
     return true;
 }
 
+bool FindBlockPos(CDiskBlockPos &pos, unsigned int nAddSize, unsigned int nHeight, uint64 nTime)
+{
+    bool fUpdatedLast = false;
 
+    LOCK(cs_LastBlockFile);
 
+    while (infoLastBlockFile.nSize + nAddSize >= MAX_BLOCKFILE_SIZE) {
+        printf("Leaving block file %i: %s\n", nLastBlockFile, infoLastBlockFile.ToString().c_str());
+        FILE *file = OpenBlockFile(pos);
+        FileCommit(file);
+        fclose(file);
+        file = OpenUndoFile(pos);
+        FileCommit(file);
+        fclose(file);
+        nLastBlockFile++;
+        infoLastBlockFile.SetNull();
+        pblocktree->ReadBlockFileInfo(nLastBlockFile, infoLastBlockFile); // check whether data for the new file somehow already exist; can fail just fine
+        fUpdatedLast = true;
+    }
 
-bool CBlock::CheckBlock() const
+    pos.nFile = nLastBlockFile;
+    pos.nPos = infoLastBlockFile.nSize;
+    infoLastBlockFile.nSize += nAddSize;
+    infoLastBlockFile.AddBlock(nHeight, nTime);
+
+    unsigned int nOldChunks = (pos.nPos + BLOCKFILE_CHUNK_SIZE - 1) / BLOCKFILE_CHUNK_SIZE;
+    unsigned int nNewChunks = (infoLastBlockFile.nSize + BLOCKFILE_CHUNK_SIZE - 1) / BLOCKFILE_CHUNK_SIZE;
+    if (nNewChunks > nOldChunks) {
+        FILE *file = OpenBlockFile(pos);
+        if (file) {
+            printf("Pre-allocating up to position 0x%x in blk%05u.dat\n", nNewChunks * BLOCKFILE_CHUNK_SIZE, pos.nFile);
+            AllocateFileRange(file, pos.nPos, nNewChunks * BLOCKFILE_CHUNK_SIZE - pos.nPos);
+        }
+        fclose(file);
+    }
+
+    if (!pblocktree->WriteBlockFileInfo(nLastBlockFile, infoLastBlockFile))
+        return error("FindBlockPos() : cannot write updated block info");
+    if (fUpdatedLast)
+        pblocktree->WriteLastBlockFile(nLastBlockFile);
+
+    return true;
+}
+
+bool FindUndoPos(int nFile, CDiskBlockPos &pos, unsigned int nAddSize)
+{
+    pos.nFile = nFile;
+
+    LOCK(cs_LastBlockFile);
+
+    unsigned int nNewSize;
+    if (nFile == nLastBlockFile) {
+        pos.nPos = infoLastBlockFile.nUndoSize;
+        nNewSize = (infoLastBlockFile.nUndoSize += nAddSize);
+        if (!pblocktree->WriteBlockFileInfo(nLastBlockFile, infoLastBlockFile))
+            return error("FindUndoPos() : cannot write updated block info");
+    } else {
+        CBlockFileInfo info;
+        if (!pblocktree->ReadBlockFileInfo(nFile, info))
+            return error("FindUndoPos() : cannot read block info");
+        pos.nPos = info.nUndoSize;
+        nNewSize = (info.nUndoSize += nAddSize);
+        if (!pblocktree->WriteBlockFileInfo(nFile, info))
+            return error("FindUndoPos() : cannot write updated block info");
+    }
+
+    unsigned int nOldChunks = (pos.nPos + UNDOFILE_CHUNK_SIZE - 1) / UNDOFILE_CHUNK_SIZE;
+    unsigned int nNewChunks = (nNewSize + UNDOFILE_CHUNK_SIZE - 1) / UNDOFILE_CHUNK_SIZE;
+    if (nNewChunks > nOldChunks) {
+        FILE *file = OpenUndoFile(pos);
+        if (file) {
+            printf("Pre-allocating up to position 0x%x in rev%05u.dat\n", nNewChunks * UNDOFILE_CHUNK_SIZE, pos.nFile);
+            AllocateFileRange(file, pos.nPos, nNewChunks * UNDOFILE_CHUNK_SIZE - pos.nPos);
+        }
+        fclose(file);
+    }
+
+    return true;
+}
+
+bool CBlock::CheckBlock(bool fCheckPOW, bool fCheckMerkleRoot, bool fCheckSig) const
 {
     // These are checks that are independent of context
     // that can be verified before saving an orphan block.
@@ -1869,11 +2241,11 @@ bool CBlock::CheckBlock() const
         return DoS(100, error("CheckBlock() : size limits failed"));
 
     // Check proof of work matches claimed amount
-    if (IsProofOfWork() && !CheckProofOfWork(GetHash(), nBits))
+    if (fCheckPOW && IsProofOfWork() && !CheckProofOfWork(GetHash(), nBits))
         return DoS(50, error("CheckBlock() : proof of work failed"));
 
     // Check timestamp
-    if (GetBlockTime() > GetAdjustedTime() + nMaxClockDrift)
+    if (GetBlockTime() > GetAdjustedTime() + 2 * 60 * 60)
         return error("CheckBlock() : block timestamp too far in the future");
 
     // First transaction must be coinbase, the rest must not be
@@ -1883,45 +2255,70 @@ bool CBlock::CheckBlock() const
         if (vtx[i].IsCoinBase())
             return DoS(100, error("CheckBlock() : more than one coinbase"));
 
-    // ppcoin: only the second transaction can be the optional coinstake
-    for (int i = 2; i < vtx.size(); i++)
-        if (vtx[i].IsCoinStake())
-            return DoS(100, error("CheckBlock() : coinstake in wrong position"));
-
-    // ppcoin: coinbase output should be empty if proof-of-stake block
-    if (IsProofOfStake() && (vtx[0].vout.size() != 1 || !vtx[0].vout[0].IsEmpty()))
-        return error("CheckBlock() : coinbase output not empty for proof-of-stake block");
-
     // Check coinbase timestamp
-    if (GetBlockTime() > (int64)vtx[0].nTime + nMaxClockDrift)
+    if (GetBlockTime() > FutureDrift((int64)vtx[0].nTime))
         return DoS(50, error("CheckBlock() : coinbase timestamp is too early"));
 
-    // Check coinstake timestamp
-    if (IsProofOfStake() && !CheckCoinStakeTimestamp(GetBlockTime(), (int64)vtx[1].nTime))
-        return DoS(50, error("CheckBlock() : coinstake timestamp violation nTimeBlock=%u nTimeTx=%u", GetBlockTime(), vtx[1].nTime));
+    if (IsProofOfStake())
+    {
+        // 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"));
+
+        // Second transaction must be coinstake, the rest must not be
+        if (vtx.empty() || !vtx[1].IsCoinStake())
+            return DoS(100, error("CheckBlock() : second tx is not coinstake"));
+        for (unsigned int i = 2; i < vtx.size(); i++)
+            if (vtx[i].IsCoinStake())
+                return DoS(100, error("CheckBlock() : more than one coinstake"));
+
+        // Check coinstake timestamp
+        if (!CheckCoinStakeTimestamp(GetBlockTime(), (int64)vtx[1].nTime))
+            return DoS(50, error("CheckBlock() : coinstake timestamp violation nTimeBlock=%"PRI64d" nTimeTx=%u", GetBlockTime(), vtx[1].nTime));
+    }
+    else
+    {
+        int64 nReward = GetProofOfWorkReward(nBits);
+        // Check coinbase reward
+        if (vtx[0].GetValueOut() > nReward)
+            return DoS(50, error("CheckBlock() : coinbase reward exceeded (actual=%"PRI64d" vs calculated=%"PRI64d")",
+                   vtx[0].GetValueOut(),
+                   nReward));
+
+        // Should we check proof-of-work block signature or not?
+        //
+        // * Always skip on TestNet
+        // * Perform checking for the first 9689 blocks
+        // * Perform checking since last checkpoint until 20 Sep 2013 (will be removed after)
+
+        if(!fTestNet && fCheckSig)
+        {
+            bool checkEntropySig = (GetBlockTime() < ENTROPY_SWITCH_TIME);
+
+            // check legacy proof-of-work block signature
+            if (checkEntropySig && !CheckLegacySignature())
+                return DoS(100, error("CheckBlock() : bad proof-of-work block signature"));
+        }
+    }
 
-    // Check coinbase reward
-    if (vtx[0].GetValueOut() > (IsProofOfWork()? (GetProofOfWorkReward(nBits) - vtx[0].GetMinFee() + MIN_TX_FEE) : 0))
-        return DoS(50, error("CheckBlock() : coinbase reward exceeded %s > %s", 
-                   FormatMoney(vtx[0].GetValueOut()).c_str(),
-                   FormatMoney(IsProofOfWork()? GetProofOfWorkReward(nBits) : 0).c_str()));
 
     // Check transactions
     BOOST_FOREACH(const CTransaction& tx, vtx)
     {
         if (!tx.CheckTransaction())
             return DoS(tx.nDoS, error("CheckBlock() : CheckTransaction failed"));
-        // ppcoin: check transaction timestamp
+
+        // 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(),
     // but catching it earlier avoids a potential DoS attack:
+    BuildMerkleTree();
     set<uint256> uniqueTx;
-    BOOST_FOREACH(const CTransaction& tx, vtx)
-    {
-        uniqueTx.insert(tx.GetHash());
+    for (unsigned int i=0; i<vtx.size(); i++) {
+        uniqueTx.insert(GetTxHash(i));
     }
     if (uniqueTx.size() != vtx.size())
         return DoS(100, error("CheckBlock() : duplicate transaction"));
@@ -1934,35 +2331,13 @@ bool CBlock::CheckBlock() const
     if (nSigOps > MAX_BLOCK_SIGOPS)
         return DoS(100, error("CheckBlock() : out-of-bounds SigOpCount"));
 
-    // Check merkleroot
-    if (hashMerkleRoot != BuildMerkleTree())
+    // Check merkle root
+    if (fCheckMerkleRoot && hashMerkleRoot != BuildMerkleTree())
         return DoS(100, error("CheckBlock() : hashMerkleRoot mismatch"));
 
-    // ppcoin: check block signature
-    if (!CheckBlockSignature())
-        return DoS(100, error("CheckBlock() : bad block signature"));
-
     return true;
 }
 
-int CBlock::GetBlockHeight() const
-{
-    if(nVersion == 1)
-        return 0;
-
-    if(vtx[0].vin[0].scriptSig[0] > 4)
-        return vtx[0].vin[0].scriptSig[0] - 80;
-
-    int nBlockHeight = 0;
-
-    memcpy((void *)&nBlockHeight, (const void *)&vtx[0].vin[0].scriptSig[1], vtx[0].vin[0].scriptSig[0]);
-
-#ifdef BIGENDIAN
-    return htonl(nBlockHeight);
-#else
-    return nBlockHeight;
-#endif
-}
 
 bool CBlock::AcceptBlock()
 {
@@ -1980,10 +2355,10 @@ bool CBlock::AcceptBlock()
 
     // Check proof-of-work or proof-of-stake
     if (nBits != GetNextTargetRequired(pindexPrev, IsProofOfStake()))
-        return DoS(100, error("AcceptBlock() : incorrect proof-of-work/proof-of-stake"));
+        return DoS(100, error("AcceptBlock() : incorrect proof-of-%s amount", IsProofOfWork() ? "work" : "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
@@ -1991,38 +2366,37 @@ bool CBlock::AcceptBlock()
         if (!tx.IsFinal(nHeight, GetBlockTime()))
             return DoS(10, error("AcceptBlock() : contains a non-final transaction"));
 
-    // Check that the block chain matches the known block chain up to a hardened checkpoint
+    // Check that the block chain matches the known block chain up to a checkpoint
     if (!Checkpoints::CheckHardened(nHeight, hash))
-        return DoS(100, error("AcceptBlock() : rejected by hardened checkpoint lockin at %d", nHeight));
+        return DoS(100, error("AcceptBlock() : rejected by hardened checkpoint lock-in at %d", nHeight));
 
-    // ppcoin: check that the block satisfies synchronized checkpoint
-    if (!Checkpoints::CheckSync(hash, pindexPrev))
+    bool cpSatisfies = Checkpoints::CheckSync(hash, pindexPrev);
+
+    // Check that the block satisfies synchronized checkpoint
+    if (CheckpointsMode == Checkpoints::STRICT && !cpSatisfies)
         return error("AcceptBlock() : rejected by synchronized checkpoint");
 
-    // Reject block.nVersion < 3 blocks since 95% threshold on mainNet and always on testNet:
-    if (nVersion < 3 && ((!fTestNet && nHeight > 14060) || (fTestNet && nHeight > 0)))
-        return error("CheckBlock() : rejected nVersion < 3 block");
+    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"));
 
-    /**
-      * TODO: replace previous check with this.
-      */
-
-    // if(nHeight != GetBlockHeight())
-    //    return DoS(100, error("AcceptBlock() : block height mismatch in coinbase"));
-
-
     // Write block to history file
+    unsigned int nBlockSize = ::GetSerializeSize(*this, SER_DISK, CLIENT_VERSION);
     if (!CheckDiskSpace(::GetSerializeSize(*this, SER_DISK, CLIENT_VERSION)))
         return error("AcceptBlock() : out of disk space");
-    unsigned int nFile = -1;
-    unsigned int nBlockPos = 0;
-    if (!WriteToDisk(nFile, nBlockPos))
+    CDiskBlockPos blockPos;
+    {
+        if (!FindBlockPos(blockPos, nBlockSize+8, nHeight, nTime))
+            return error("AcceptBlock() : FindBlockPos failed");
+    }
+    if (!WriteToDisk(blockPos))
         return error("AcceptBlock() : WriteToDisk failed");
-    if (!AddToBlockIndex(nFile, nBlockPos))
+    if (!AddToBlockIndex(blockPos))
         return error("AcceptBlock() : AddToBlockIndex failed");
 
     // Relay inventory, but don't relay old inventory during initial block download
@@ -2035,12 +2409,108 @@ bool CBlock::AcceptBlock()
                 pnode->PushInventory(CInv(MSG_BLOCK, hash));
     }
 
-    // ppcoin: check pending sync-checkpoint
+    // Check pending sync-checkpoint
     Checkpoints::AcceptPendingSyncCheckpoint();
 
     return true;
 }
 
+uint256 CBlockIndex::GetBlockTrust() const
+{
+    CBigNum bnTarget;
+    bnTarget.SetCompact(nBits);
+
+    if (bnTarget <= 0)
+        return 0;
+
+    /* Old protocol */
+    if (!fTestNet && GetBlockTime() < CHAINCHECKS_SWITCH_TIME)
+        return (IsProofOfStake()? ((CBigNum(1)<<256) / (bnTarget+1)).getuint256() : 1);
+
+    /* New protocol */
+
+    // Calculate work amount for block
+    uint256 nPoWTrust = (CBigNum(nPoWBase) / (bnTarget+1)).getuint256();
+
+    // Set nPowTrust to 1 if we are checking PoS block or PoW difficulty is too low
+    nPoWTrust = (IsProofOfStake() || nPoWTrust < 1) ? 1 : nPoWTrust;
+
+    // Return nPoWTrust for the first 12 blocks
+    if (pprev == NULL || pprev->nHeight < 12)
+        return nPoWTrust;
+
+    const CBlockIndex* currentIndex = pprev;
+
+    if(IsProofOfStake())
+    {
+        CBigNum bnNewTrust = (CBigNum(1)<<256) / (bnTarget+1);
+
+        // Return 1/3 of score if parent block is not the PoW block
+        if (!pprev->IsProofOfWork())
+            return (bnNewTrust / 3).getuint256();
+
+        int nPoWCount = 0;
+
+        // Check last 12 blocks type
+        while (pprev->nHeight - currentIndex->nHeight < 12)
+        {
+            if (currentIndex->IsProofOfWork())
+                nPoWCount++;
+            currentIndex = currentIndex->pprev;
+        }
+
+        // Return 1/3 of score if less than 3 PoW blocks found
+        if (nPoWCount < 3)
+            return (bnNewTrust / 3).getuint256();
+
+        return bnNewTrust.getuint256();
+    }
+    else
+    {
+        CBigNum bnLastBlockTrust = CBigNum(pprev->nChainTrust - pprev->pprev->nChainTrust);
+
+        // Return nPoWTrust + 2/3 of previous block score if two parent blocks are not PoS blocks
+        if (!(pprev->IsProofOfStake() && pprev->pprev->IsProofOfStake()))
+            return nPoWTrust + (2 * bnLastBlockTrust / 3).getuint256();
+
+        int nPoSCount = 0;
+
+        // Check last 12 blocks type
+        while (pprev->nHeight - currentIndex->nHeight < 12)
+        {
+            if (currentIndex->IsProofOfStake())
+                nPoSCount++;
+            currentIndex = currentIndex->pprev;
+        }
+
+        // Return nPoWTrust + 2/3 of previous block score if less than 7 PoS blocks found
+        if (nPoSCount < 7)
+            return nPoWTrust + (2 * bnLastBlockTrust / 3).getuint256();
+
+        bnTarget.SetCompact(pprev->nBits);
+
+        if (bnTarget <= 0)
+            return 0;
+
+        CBigNum bnNewTrust = (CBigNum(1)<<256) / (bnTarget+1);
+
+        // Return nPoWTrust + full trust score for previous block nBits
+        return nPoWTrust + bnNewTrust.getuint256();
+    }
+}
+
+bool CBlockIndex::IsSuperMajority(int minVersion, const CBlockIndex* pstart, unsigned int nRequired, unsigned int nToCheck)
+{
+    unsigned int nFound = 0;
+    for (unsigned int i = 0; i < nToCheck && nFound < nRequired && pstart != NULL; i++)
+    {
+        if (pstart->nVersion >= minVersion)
+            ++nFound;
+        pstart = pstart->pprev;
+    }
+    return (nFound >= nRequired);
+}
+
 bool ProcessBlock(CNode* pfrom, CBlock* pblock)
 {
     // Check for duplicate
@@ -2050,25 +2520,44 @@ bool ProcessBlock(CNode* pfrom, CBlock* pblock)
     if (mapOrphanBlocks.count(hash))
         return error("ProcessBlock() : already have block (orphan) %s", hash.ToString().substr(0,20).c_str());
 
-    // ppcoin: check proof-of-stake
-    // Limited duplicity on stake: prevents block flood attack
-    // Duplicate stake allowed only when there is orphan child block
-    if (pblock->IsProofOfStake() && setStakeSeen.count(pblock->GetProofOfStake()) && !mapOrphanBlocksByPrev.count(hash) && !Checkpoints::WantedByPendingSyncCheckpoint(hash))
-        return error("ProcessBlock() : duplicate proof-of-stake (%s, %d) for block %s", pblock->GetProofOfStake().first.ToString().c_str(), pblock->GetProofOfStake().second, hash.ToString().c_str());
-
     // Preliminary checks
     if (!pblock->CheckBlock())
         return error("ProcessBlock() : CheckBlock FAILED");
 
-    // ppcoin: verify hash target and signature of coinstake tx
     if (pblock->IsProofOfStake())
     {
-        uint256 hashProofOfStake = 0;
-        if (!CheckProofOfStake(pblock->vtx[1], pblock->nBits, hashProofOfStake))
+        // Limited duplicity on stake: prevents block flood attack
+        // Duplicate stake allowed only when there is orphan child block
+        if (setStakeSeen.count(pblock->GetProofOfStake()) && !mapOrphanBlocksByPrev.count(hash) && !Checkpoints::WantedByPendingSyncCheckpoint(hash))
+            return error("ProcessBlock() : duplicate proof-of-stake (%s, %d) for block %s", pblock->GetProofOfStake().first.ToString().c_str(), pblock->GetProofOfStake().second, hash.ToString().c_str());
+
+        bool fFatal = false;
+        uint256 hashProofOfStake;
+
+        // Verify proof-of-stake script, hash target and signature
+        if (!pblock->CheckSignature(fFatal, hashProofOfStake))
         {
-            printf("WARNING: ProcessBlock(): check proof-of-stake failed for block %s\n", hash.ToString().c_str());
-            return false; // do not error here as we expect this during initial block download
+            if (fFatal)
+            {
+                // Invalid coinstake script, blockhash signature or no generator defined, nothing to do here
+                // This also may occur when supplied proof-of-stake doesn't satisfy required target
+                if (pfrom)
+                    pfrom->Misbehaving(100);
+                return error("ProcessBlock() : invalid signatures found in proof-of-stake block %s", hash.ToString().c_str());
+            }
+            else
+            {
+                // Blockhash and coinstake signatures are OK but target checkings failed
+                // This may occur during initial block download
+
+                if (pfrom)
+                    pfrom->Misbehaving(1); // Small DoS penalty
+
+                printf("WARNING: ProcessBlock(): proof-of-stake target checkings failed for block %s, we'll try again later\n", hash.ToString().c_str());
+                return false;
+            }
         }
+
         if (!mapProofOfStake.count(hash)) // add to mapProofOfStake
             mapProofOfStake.insert(make_pair(hash, hashProofOfStake));
     }
@@ -2081,17 +2570,21 @@ bool ProcessBlock(CNode* pfrom, CBlock* pblock)
         CBigNum bnNewBlock;
         bnNewBlock.SetCompact(pblock->nBits);
         CBigNum bnRequired;
-        bnRequired.SetCompact(ComputeMinWork(GetLastBlockIndex(pcheckpoint, pblock->IsProofOfStake())->nBits, deltaTime, pblock->IsProofOfStake(), pblock->GetBlockHeight()));
+
+        if (pblock->IsProofOfStake())
+            bnRequired.SetCompact(ComputeMinStake(GetLastBlockIndex(pcheckpoint, true)->nBits, deltaTime, pblock->nTime));
+        else
+            bnRequired.SetCompact(ComputeMinWork(GetLastBlockIndex(pcheckpoint, false)->nBits, deltaTime));
 
         if (bnNewBlock > bnRequired)
         {
             if (pfrom)
                 pfrom->Misbehaving(100);
-            return error("ProcessBlock() : block with too little %s", pblock->IsProofOfStake()? "proof-of-stake" : "proof-of-work");
+            return error("ProcessBlock() : block with too little proof-of-%s", pblock->IsProofOfStake() ? "stake" : "work");
         }
     }
 
-    // ppcoin: ask for pending sync-checkpoint if any
+    // Ask for pending sync-checkpoint if any
     if (!IsInitialBlockDownload())
         Checkpoints::AskForPendingSyncCheckpoint(pfrom);
 
@@ -2100,7 +2593,7 @@ bool ProcessBlock(CNode* pfrom, CBlock* pblock)
     {
         printf("ProcessBlock: ORPHAN BLOCK, prev=%s\n", pblock->hashPrevBlock.ToString().substr(0,20).c_str());
         CBlock* pblock2 = new CBlock(*pblock);
-        // ppcoin: check proof-of-stake
+
         if (pblock2->IsProofOfStake())
         {
             // Limited duplicity on stake: prevents block flood attack
@@ -2110,6 +2603,7 @@ bool ProcessBlock(CNode* pfrom, CBlock* pblock)
             else
                 setStakeSeenOrphan.insert(pblock2->GetProofOfStake());
         }
+
         mapOrphanBlocks.insert(make_pair(hash, pblock2));
         mapOrphanBlocksByPrev.insert(make_pair(pblock2->hashPrevBlock, pblock2));
 
@@ -2158,147 +2652,192 @@ bool ProcessBlock(CNode* pfrom, CBlock* pblock)
     return true;
 }
 
-// ppcoin: sign block
-bool CBlock::SignBlock(const CKeyStore& keystore)
+// attempt to generate suitable proof-of-stake
+bool CBlock::SignBlock(CWallet& wallet)
 {
-    vector<valtype> vSolutions;
-    txnouttype whichType;
-
-    if(!IsProofOfStake())
-    {
-        for(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;
+    if (nSearchTime > nLastCoinStakeSearchTime)
+    {
+        if (wallet.CreateCoinStake(wallet, nBits, nSearchTime-nLastCoinStakeSearchTime, txCoinStake, key))
+        {
+            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;
     }
-    else
-    {
-        const CTxOut& txout = vtx[1].vout[1];
 
-        if (!Solver(txout.scriptPubKey, whichType, vSolutions))
-            return false;
+    return false;
+}
 
-        if (whichType == TX_PUBKEY)
-        {
-            // Sign
-            valtype& vchPubKey = vSolutions[0];
-            CKey key;
+// get generation key
+bool CBlock::GetGenerator(CKey& GeneratorKey) const
+{
+    if(!IsProofOfStake())
+        return false;
 
-            if (!keystore.GetKey(Hash160(vchPubKey), key))
-                return false;
-            if (key.GetPubKey() != vchPubKey)
-                return false;
+    vector<valtype> vSolutions;
+    txnouttype whichType;
 
-            return key.Sign(GetHash(), vchBlockSig);
-        }
+    const CTxOut& txout = vtx[1].vout[1];
+
+    if (!Solver(txout.scriptPubKey, whichType, vSolutions))
+        return false;
+    if (whichType == TX_PUBKEY)
+    {
+        valtype& vchPubKey = vSolutions[0];
+        CKey key;
+        return GeneratorKey.SetPubKey(vchPubKey);
     }
 
-    printf("Sign failed\n");
     return false;
 }
 
-// ppcoin: check block signature
-bool CBlock::CheckBlockSignature() const
+// verify proof-of-stake signatures
+bool CBlock::CheckSignature(bool& fFatal, uint256& hashProofOfStake) const
 {
-    if (GetHash() == hashGenesisBlock)
-        return vchBlockSig.empty();
+    CKey key;
+
+    // no generator or invalid hash signature means fatal error
+    fFatal = !GetGenerator(key) || !key.Verify(GetHash(), vchBlockSig);
+
+    if (fFatal)
+        return false;
+
+    uint256 hashTarget = 0;
+    if (!CheckProofOfStake(vtx[1], nBits, hashProofOfStake, hashTarget, fFatal))
+        return false; // hash target mismatch or invalid coinstake signature
+
+    return true;
+}
+
+// verify legacy proof-of-work signature
+bool CBlock::CheckLegacySignature() const
+{
+    if (IsProofOfStake())
+        return false;
 
     vector<valtype> vSolutions;
     txnouttype whichType;
 
-    if(IsProofOfStake())
+    for(unsigned int i = 0; i < vtx[0].vout.size(); i++)
     {
-        const CTxOut& txout = vtx[1].vout[1];
+        const CTxOut& txout = vtx[0].vout[i];
 
         if (!Solver(txout.scriptPubKey, whichType, vSolutions))
             return false;
+
         if (whichType == TX_PUBKEY)
         {
+            // Verify
             valtype& vchPubKey = vSolutions[0];
             CKey key;
             if (!key.SetPubKey(vchPubKey))
-                return false;
+                continue;
             if (vchBlockSig.empty())
-                return false;
-            return key.Verify(GetHash(), vchBlockSig);
+                continue;
+            if(!key.Verify(GetHash(), vchBlockSig))
+                continue;
+            return true;
         }
     }
-    else
-    {
-        for(int i = 0; i < vtx[0].vout.size(); i++)
-        {
-            const CTxOut& txout = vtx[0].vout[i];
-
-            if (!Solver(txout.scriptPubKey, whichType, vSolutions))
-                return false;
 
-            if (whichType == TX_PUBKEY)
-            {
-                // Verify
-                valtype& vchPubKey = vSolutions[0];
-                CKey key;
-                if (!key.SetPubKey(vchPubKey))
-                    continue;
-                if (vchBlockSig.empty())
-                    continue;
-                if(!key.Verify(GetHash(), vchBlockSig))
-                    continue;
+    return false;
+}
 
-                return true;
-            }
-        }
+// entropy bit for stake modifier if chosen by modifier
+unsigned int CBlock::GetStakeEntropyBit(unsigned int nTime) const
+{
+    // Protocol switch at novacoin block #9689
+    if (nTime >= ENTROPY_SWITCH_TIME || fTestNet)
+    {
+        // Take last bit of block hash as entropy bit
+        unsigned int nEntropyBit = ((GetHash().Get64()) & 1llu);
+        if (fDebug && GetBoolArg("-printstakemodifier"))
+            printf("GetStakeEntropyBit: nTime=%u hashBlock=%s nEntropyBit=%u\n", nTime, GetHash().ToString().c_str(), nEntropyBit);
+        return nEntropyBit;
     }
-    return false;
+    // Before novacoin block #9689 - old protocol
+    uint160 hashSig = Hash160(vchBlockSig);
+    if (fDebug && GetBoolArg("-printstakemodifier"))
+        printf("GetStakeEntropyBit: hashSig=%s", hashSig.ToString().c_str());
+    hashSig >>= 159; // take the first bit of the hash
+    if (fDebug && GetBoolArg("-printstakemodifier"))
+        printf(" entropybit=%"PRI64d"\n", hashSig.Get64());
+    return hashSig.Get64();
 }
 
 bool CheckDiskSpace(uint64 nAdditionalBytes)
 {
     uint64 nFreeBytesAvailable = filesystem::space(GetDataDir()).available;
 
-    // Check for 15MB because database could create another 10MB log file at any time
-    if (nFreeBytesAvailable < (uint64)15000000 + nAdditionalBytes)
+    // Check for nMinDiskSpace bytes (currently 50MB)
+    if (nFreeBytesAvailable < nMinDiskSpace + nAdditionalBytes)
     {
         fShutdown = true;
-        string strMessage = _("Warning: Disk space is low");
+        string strMessage = _("Warning: Disk space is low!");
         strMiscWarning = strMessage;
         printf("*** %s\n", strMessage.c_str());
-        ThreadSafeMessageBox(strMessage, "NovaCoin", wxOK | wxICON_EXCLAMATION | wxMODAL);
+        uiInterface.ThreadSafeMessageBox(strMessage, "NovaCoin", CClientUIInterface::OK | CClientUIInterface::ICON_EXCLAMATION | CClientUIInterface::MODAL);
         StartShutdown();
         return false;
     }
     return true;
 }
 
-FILE* OpenBlockFile(unsigned int nFile, unsigned int nBlockPos, const char* pszMode)
+
+CCriticalSection cs_LastBlockFile;
+CBlockFileInfo infoLastBlockFile;
+int nLastBlockFile = 0;
+
+FILE* OpenDiskFile(const CDiskBlockPos &pos, const char *prefix, bool fReadOnly)
 {
-    if (nFile == -1)
+    if (pos.IsNull())
         return NULL;
-    FILE* file = fopen((GetDataDir() / strprintf("blk%04d.dat", nFile)).string().c_str(), pszMode);
-    if (!file)
+    boost::filesystem::path path = GetDataDir() / "blocks" / strprintf("%s%05u.dat", prefix, pos.nFile);
+    boost::filesystem::create_directories(path.parent_path());
+    FILE* file = fopen(path.string().c_str(), "rb+");
+    if (!file && !fReadOnly)
+        file = fopen(path.string().c_str(), "wb+");
+    if (!file) {
+        printf("Unable to open file %s\n", path.string().c_str());
         return NULL;
-    if (nBlockPos != 0 && !strchr(pszMode, 'a') && !strchr(pszMode, 'w'))
-    {
-        if (fseek(file, nBlockPos, SEEK_SET) != 0)
-        {
+    }
+    if (pos.nPos) {
+        if (fseek(file, pos.nPos, SEEK_SET)) {
+            printf("Unable to seek to position %u of %s\n", pos.nPos, path.string().c_str());
             fclose(file);
             return NULL;
         }
@@ -2306,48 +2845,169 @@ FILE* OpenBlockFile(unsigned int nFile, unsigned int nBlockPos, const char* pszM
     return file;
 }
 
-static unsigned int nCurrentBlockFile = 1;
+FILE* OpenBlockFile(const CDiskBlockPos &pos, bool fReadOnly) {
+    return OpenDiskFile(pos, "blk", fReadOnly);
+}
+
+FILE *OpenUndoFile(const CDiskBlockPos &pos, bool fReadOnly) {
+    return OpenDiskFile(pos, "rev", fReadOnly);
+}
 
-FILE* AppendBlockFile(unsigned int& nFileRet)
+CBlockIndex * InsertBlockIndex(uint256 hash)
 {
-    nFileRet = 0;
-    loop
+    if (hash == 0)
+        return NULL;
+
+    // Return existing
+    map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(hash);
+    if (mi != mapBlockIndex.end())
+        return (*mi).second;
+
+    // Create new
+    CBlockIndex* pindexNew = new CBlockIndex();
+    if (!pindexNew)
+        throw runtime_error("InsertBlockIndex() : new CBlockIndex failed");
+    mi = mapBlockIndex.insert(make_pair(hash, pindexNew)).first;
+    pindexNew->phashBlock = &((*mi).first);
+
+    return pindexNew;
+}
+
+bool static LoadBlockIndexDB()
+{
+    if (!pblocktree->LoadBlockIndexGuts())
+        return false;
+
+    if (fRequestShutdown)
+        return true;
+
+    // Calculate nChainTrust
+    vector<pair<int, CBlockIndex*> > vSortedByHeight;
+    vSortedByHeight.reserve(mapBlockIndex.size());
+    BOOST_FOREACH(const PAIRTYPE(uint256, CBlockIndex*)& item, mapBlockIndex)
     {
-        FILE* file = OpenBlockFile(nCurrentBlockFile, 0, "ab");
-        if (!file)
-            return NULL;
-        if (fseek(file, 0, SEEK_END) != 0)
-            return NULL;
-        // FAT32 filesize max 4GB, fseek and ftell max 2GB, so we must stay under 2GB
-        if (ftell(file) < 0x7F000000 - MAX_SIZE)
+        CBlockIndex* pindex = item.second;
+        vSortedByHeight.push_back(make_pair(pindex->nHeight, pindex));
+    }
+    sort(vSortedByHeight.begin(), vSortedByHeight.end());
+    BOOST_FOREACH(const PAIRTYPE(int, CBlockIndex*)& item, vSortedByHeight)
+    {
+        CBlockIndex* pindex = item.second;
+        pindex->nChainTrust = (pindex->pprev ? pindex->pprev->nChainTrust : 0) + pindex->GetBlockTrust();
+        pindex->nChainTx = (pindex->pprev ? pindex->pprev->nChainTx : 0) + pindex->nTx;
+        if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TRANSACTIONS && !(pindex->nStatus & BLOCK_FAILED_MASK))
+            setBlockIndexValid.insert(pindex);
+
+        // Calculate stake modifier checksum
+        pindex->nStakeModifierChecksum = GetStakeModifierChecksum(pindex);
+        if (!CheckStakeModifierCheckpoints(pindex->nHeight, pindex->nStakeModifierChecksum))
+            return error("LoadBlockIndexDB() : Failed stake modifier checkpoint height=%d, modifier=0x%016"PRI64x, pindex->nHeight, pindex->nStakeModifier);
+    }
+
+    // Load block file info
+    pblocktree->ReadLastBlockFile(nLastBlockFile);
+    printf("LoadBlockIndexDB(): last block file = %i\n", nLastBlockFile);
+    if (pblocktree->ReadBlockFileInfo(nLastBlockFile, infoLastBlockFile))
+        printf("LoadBlockIndexDB(): last block file: %s\n", infoLastBlockFile.ToString().c_str());
+
+    // Load hashBestChain pointer to end of best chain
+    pindexBest = pcoinsTip->GetBestBlock();
+    if (pindexBest == NULL)
+    {
+        if (pindexGenesisBlock == NULL)
+            return true;
+        return error("LoadBlockIndexDB() : hashBestChain not loaded");
+    }
+    hashBestChain = pindexBest->GetBlockHash();
+    nBestHeight = pindexBest->nHeight;
+    nBestChainTrust = pindexBest->nChainTrust;
+
+    // set 'next' pointers in best chain
+    CBlockIndex *pindex = pindexBest;
+    while(pindex != NULL && pindex->pprev != NULL) {
+         CBlockIndex *pindexPrev = pindex->pprev;
+         pindexPrev->pnext = pindex;
+         pindex = pindexPrev;
+    }
+    printf("LoadBlockIndexDB(): hashBestChain=%s  height=%d date=%s\n",
+        hashBestChain.ToString().substr(0,20).c_str(), nBestHeight,
+        DateTimeStrFormat("%x %H:%M:%S", pindexBest->GetBlockTime()).c_str());
+
+    // Load sync-checkpoint
+    if (!pblocktree->ReadSyncCheckpoint(Checkpoints::hashSyncCheckpoint))
+        return error("LoadBlockIndexDB() : hashSyncCheckpoint not loaded");
+    printf("LoadBlockIndexDB(): synchronized checkpoint %s\n", Checkpoints::hashSyncCheckpoint.ToString().c_str());
+
+    // Load bnBestInvalidTrust, OK if it doesn't exist
+    CBigNum bnBestInvalidTrust;
+    pblocktree->ReadBestInvalidTrust(bnBestInvalidTrust);
+    nBestInvalidTrust = bnBestInvalidTrust.getuint256();
+
+    // Verify blocks in the best chain
+    int nCheckLevel = GetArg("-checklevel", 1);
+    int nCheckDepth = GetArg( "-checkblocks", 288);
+    if (nCheckDepth == 0)
+        nCheckDepth = 1000000000; // suffices until the year 19000
+    if (nCheckDepth > nBestHeight)
+        nCheckDepth = nBestHeight;
+    printf("Verifying last %i blocks at level %i\n", nCheckDepth, nCheckLevel);
+    CBlockIndex* pindexFork = NULL;
+    for (CBlockIndex* pindex = pindexBest; pindex && pindex->pprev; pindex = pindex->pprev)
+    {
+        if (fRequestShutdown || pindex->nHeight < nBestHeight-nCheckDepth)
+            break;
+        CBlock block;
+        if (!block.ReadFromDisk(pindex))
+            return error("LoadBlockIndexDB() : block.ReadFromDisk failed");
+        // check level 1: verify block validity
+        if (nCheckLevel>0 && !block.CheckBlock())
         {
-            nFileRet = nCurrentBlockFile;
-            return file;
+            printf("LoadBlockIndexDB() : *** found bad block at %d, hash=%s\n", pindex->nHeight, pindex->GetBlockHash().ToString().c_str());
+            pindexFork = pindex->pprev;
         }
-        fclose(file);
-        nCurrentBlockFile++;
+        // TODO: stronger verifications
+    }
+    if (pindexFork && !fRequestShutdown)
+    {
+        // TODO: reorg back
+        return error("LoadBlockIndexDB(): chain database corrupted");
     }
+
+    return true;
 }
 
+
 bool LoadBlockIndex(bool fAllowNew)
 {
+    CBigNum bnTrustedModulus;
+
     if (fTestNet)
     {
-        hashGenesisBlock = hashGenesisBlockTestNet;
-        nStakeMinAge = 60 * 60 * 24; // test net min age is 1 day
-        nCoinbaseMaturity = 60;
+        pchMessageStart[0] = 0xcd;
+        pchMessageStart[1] = 0xf2;
+        pchMessageStart[2] = 0xc0;
+        pchMessageStart[3] = 0xef;
+
+        bnTrustedModulus.SetHex("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");
+        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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");
     }
 
-    printf("%s Network: genesis=0x%s nBitsLimit=0x%08x nBitsInitial=0x%08x nStakeMinAge=%d nCoinbaseMaturity=%d nModifierInterval=%d\n",
-           fTestNet? "Test" : "NovaCoin", hashGenesisBlock.ToString().substr(0, 20).c_str(), bnProofOfWorkLimit.GetCompact(), bnInitialHashTarget.GetCompact(), nStakeMinAge, nCoinbaseMaturity, nModifierInterval);
+    // Set up the Zerocoin Params object
+    ZCParams = new libzerocoin::Params(bnTrustedModulus);
 
     //
-    // Load block index
+    // Load block index from databases
     //
-    CTxDB txdb("cr");
-    if (!txdb.LoadBlockIndex())
+    if (!LoadBlockIndexDB())
         return false;
-    txdb.Close();
 
     //
     // Init with genesis block
@@ -2358,6 +3018,23 @@ bool LoadBlockIndex(bool fAllowNew)
             return false;
 
         // Genesis block
+
+        // MainNet:
+
+        //CBlock(hash=00000a060336cbb72fe969666d337b87198b1add2abaa59cca226820b32933a4, ver=1, hashPrevBlock=0000000000000000000000000000000000000000000000000000000000000000, hashMerkleRoot=4cb33b3b6a861dcbc685d3e614a9cafb945738d6833f182855679f2fad02057b, nTime=1360105017, nBits=1e0fffff, nNonce=1575379, vtx=1, vchBlockSig=)
+        //  Coinbase(hash=4cb33b3b6a, nTime=1360105017, ver=1, vin.size=1, vout.size=1, nLockTime=0)
+        //    CTxIn(COutPoint(0000000000, 4294967295), coinbase 04ffff001d020f274468747470733a2f2f626974636f696e74616c6b2e6f72672f696e6465782e7068703f746f7069633d3133343137392e6d736731353032313936236d736731353032313936)
+        //    CTxOut(empty)
+        //  vMerkleTree: 4cb33b3b6a
+
+        // TestNet:
+
+        //CBlock(hash=0000c763e402f2436da9ed36c7286f62c3f6e5dbafce9ff289bd43d7459327eb, ver=1, hashPrevBlock=0000000000000000000000000000000000000000000000000000000000000000, hashMerkleRoot=4cb33b3b6a861dcbc685d3e614a9cafb945738d6833f182855679f2fad02057b, nTime=1360105017, nBits=1f00ffff, nNonce=46534, vtx=1, vchBlockSig=)
+        //  Coinbase(hash=4cb33b3b6a, nTime=1360105017, ver=1, vin.size=1, vout.size=1, nLockTime=0)
+        //    CTxIn(COutPoint(0000000000, 4294967295), coinbase 04ffff001d020f274468747470733a2f2f626974636f696e74616c6b2e6f72672f696e6465782e7068703f746f7069633d3133343137392e6d736731353032313936236d736731353032313936)
+        //    CTxOut(empty)
+        //  vMerkleTree: 4cb33b3b6a
+
         const char* pszTimestamp = "https://bitcointalk.org/index.php?topic=134179.msg1502196#msg1502196";
         CTransaction txNew;
         txNew.nTime = 1360105017;
@@ -2372,53 +3049,52 @@ bool LoadBlockIndex(bool fAllowNew)
         block.nVersion = 1;
         block.nTime    = 1360105017;
         block.nBits    = bnProofOfWorkLimit.GetCompact();
-        block.nNonce   = 1575379;
+        block.nNonce   = !fTestNet ? 1575379 : 46534;
 
         //// debug print
+        uint256 hash = block.GetHash();
+        printf("%s\n", hash.ToString().c_str());
         assert(block.hashMerkleRoot == uint256("0x4cb33b3b6a861dcbc685d3e614a9cafb945738d6833f182855679f2fad02057b"));
         block.print();
-        assert(block.GetHash() == hashGenesisBlock);
+        assert(hash == (!fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet));
         assert(block.CheckBlock());
 
         // Start new block file
-        unsigned int nFile;
-        unsigned int nBlockPos;
-        if (!block.WriteToDisk(nFile, nBlockPos))
+        unsigned int nBlockSize = ::GetSerializeSize(block, SER_DISK, CLIENT_VERSION);
+        CDiskBlockPos blockPos;
+        if (!FindBlockPos(blockPos, nBlockSize+8, 0, block.nTime))
+            return error("AcceptBlock() : FindBlockPos failed");
+        if (!block.WriteToDisk(blockPos))
             return error("LoadBlockIndex() : writing genesis block to disk failed");
-        if (!block.AddToBlockIndex(nFile, nBlockPos))
+        if (!block.AddToBlockIndex(blockPos))
             return error("LoadBlockIndex() : genesis block not accepted");
 
-        // ppcoin: initialize synchronized checkpoint
-        if (!Checkpoints::WriteSyncCheckpoint(hashGenesisBlock))
+        // initialize synchronized checkpoint
+        if (!Checkpoints::WriteSyncCheckpoint((!fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet)))
             return error("LoadBlockIndex() : failed to init sync checkpoint");
     }
 
-    // ppcoin: if checkpoint master key changed must reset sync-checkpoint
+    string strPubKey = "";
+    // if checkpoint master key changed must reset sync-checkpoint
+    if (!pblocktree->ReadCheckpointPubKey(strPubKey) || strPubKey != CSyncCheckpoint::strMasterPubKey)
     {
-        CTxDB txdb;
-        string strPubKey = "";
-        if (!txdb.ReadCheckpointPubKey(strPubKey) || strPubKey != CSyncCheckpoint::strMasterPubKey)
         {
+            LOCK(Checkpoints::cs_hashSyncCheckpoint);
             // write checkpoint master key to db
-            txdb.TxnBegin();
-            if (!txdb.WriteCheckpointPubKey(CSyncCheckpoint::strMasterPubKey))
+            if (!pblocktree->WriteCheckpointPubKey(CSyncCheckpoint::strMasterPubKey))
                 return error("LoadBlockIndex() : failed to write new checkpoint master key to db");
-            if (!txdb.TxnCommit())
-                return error("LoadBlockIndex() : failed to commit new checkpoint master key to db");
-            if ((!fTestNet) && !Checkpoints::ResetSyncCheckpoint())
-                return error("LoadBlockIndex() : failed to reset sync-checkpoint");
         }
-        txdb.Close();
+
+        if ((!fTestNet) && !Checkpoints::ResetSyncCheckpoint())
+            return error("LoadBlockIndex() : failed to reset sync-checkpoint");
     }
 
     return true;
 }
 
-
-
 void PrintBlockTree()
 {
-    // precompute tree structure
+    // pre-compute tree structure
     map<CBlockIndex*, vector<CBlockIndex*> > mapNext;
     for (map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.begin(); mi != mapBlockIndex.end(); ++mi)
     {
@@ -2461,19 +3137,15 @@ void PrintBlockTree()
         // print item
         CBlock block;
         block.ReadFromDisk(pindex);
-        printf("%d (%u,%u) %s  %08lx  %s  mint %7s  tx %d",
+        printf("%d (blk%05u.dat:0x%x)  %s  tx %"PRIszu"",
             pindex->nHeight,
-            pindex->nFile,
-            pindex->nBlockPos,
-            block.GetHash().ToString().c_str(),
-            block.nBits,
-            DateTimeStrFormat(block.GetBlockTime()).c_str(),
-            FormatMoney(pindex->nMint).c_str(),
+            pindex->GetBlockPos().nFile, pindex->GetBlockPos().nPos,
+            DateTimeStrFormat("%x %H:%M:%S", block.GetBlockTime()).c_str(),
             block.vtx.size());
 
         PrintWallets(block);
 
-        // put the main timechain first
+        // put the main time-chain first
         vector<CBlockIndex*>& vNext = mapNext[pindex];
         for (unsigned int i = 0; i < vNext.size(); i++)
         {
@@ -2490,31 +3162,83 @@ void PrintBlockTree()
     }
 }
 
+bool LoadExternalBlockFile(FILE* fileIn)
+{
+    int64 nStart = GetTimeMillis();
 
-
-
-
-
-
-
-
+    int nLoaded = 0;
+    {
+        LOCK(cs_main);
+        try {
+            CAutoFile blkdat(fileIn, SER_DISK, CLIENT_VERSION);
+            unsigned int nPos = 0;
+            while (nPos != (unsigned int)-1 && blkdat.good() && !fRequestShutdown)
+            {
+                unsigned char pchData[65536];
+                do {
+                    fseek(blkdat, nPos, SEEK_SET);
+                    int nRead = fread(pchData, 1, sizeof(pchData), blkdat);
+                    if (nRead <= 8)
+                    {
+                        nPos = (unsigned int)-1;
+                        break;
+                    }
+                    void* nFind = memchr(pchData, pchMessageStart[0], nRead+1-sizeof(pchMessageStart));
+                    if (nFind)
+                    {
+                        if (memcmp(nFind, pchMessageStart, sizeof(pchMessageStart))==0)
+                        {
+                            nPos += ((unsigned char*)nFind - pchData) + sizeof(pchMessageStart);
+                            break;
+                        }
+                        nPos += ((unsigned char*)nFind - pchData) + 1;
+                    }
+                    else
+                        nPos += sizeof(pchData) - sizeof(pchMessageStart) + 1;
+                } while(!fRequestShutdown);
+                if (nPos == (unsigned int)-1)
+                    break;
+                fseek(blkdat, nPos, SEEK_SET);
+                unsigned int nSize;
+                blkdat >> nSize;
+                if (nSize > 0 && nSize <= MAX_BLOCK_SIZE)
+                {
+                    CBlock block;
+                    blkdat >> block;
+                    if (ProcessBlock(NULL,&block))
+                    {
+                        nLoaded++;
+                        nPos += 4 + nSize;
+                    }
+                }
+            }
+        }
+        catch (std::exception &e) {
+            printf("%s() : Deserialize or I/O error caught during load\n",
+                   __PRETTY_FUNCTION__);
+        }
+    }
+    printf("Loaded %i blocks from external file in %"PRI64d"ms\n", nLoaded, GetTimeMillis() - nStart);
+    return nLoaded > 0;
+}
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // CAlert
 //
 
-map<uint256, CAlert> mapAlerts;
-CCriticalSection cs_mapAlerts;
+extern map<uint256, CAlert> mapAlerts;
+extern CCriticalSection cs_mapAlerts;
 
-static string strMintMessage = _("Info: Minting suspended due to locked wallet."); 
-static string strMintWarning;
+extern string strMintMessage;
+extern string strMintWarning;
 
 string GetWarnings(string strFor)
 {
     int nPriority = 0;
     string strStatusBar;
     string strRPC;
+
     if (GetBoolArg("-testsafemode"))
         strRPC = "test";
 
@@ -2532,19 +3256,21 @@ string GetWarnings(string strFor)
         strStatusBar = strMiscWarning;
     }
 
-    // ppcoin: should not enter safe mode for longer invalid chain
-    // ppcoin: if sync-checkpoint is too old do not enter safe mode
-    if (Checkpoints::IsSyncCheckpointTooOld(60 * 60 * 24 * 10) && !fTestNet && !IsInitialBlockDownload())
+    // * Should not enter safe mode for longer invalid chain
+    // * If sync-checkpoint is too old do not enter safe mode
+    // * Display warning only in the STRICT mode
+    if (CheckpointsMode == Checkpoints::STRICT && Checkpoints::IsSyncCheckpointTooOld(60 * 60 * 24 * 10) &&
+        !fTestNet && !IsInitialBlockDownload())
     {
         nPriority = 100;
-        strStatusBar = "WARNING: Checkpoint is too old. Wait for block chain to download, or notify developers.";
+        strStatusBar = _("WARNING: Checkpoint is too old. Wait for block chain to download, or notify developers.");
     }
 
     // ppcoin: 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
@@ -2558,7 +3284,7 @@ string GetWarnings(string strFor)
                 nPriority = alert.nPriority;
                 strStatusBar = alert.strStatusBar;
                 if (nPriority > 1000)
-                    strRPC = strStatusBar;  // ppcoin: safe mode for high alert
+                    strRPC = strStatusBar;
             }
         }
     }
@@ -2571,53 +3297,6 @@ string GetWarnings(string strFor)
     return "error";
 }
 
-bool CAlert::ProcessAlert()
-{
-    if (!CheckSignature())
-        return false;
-    if (!IsInEffect())
-        return false;
-
-    {
-        LOCK(cs_mapAlerts);
-        // Cancel previous alerts
-        for (map<uint256, CAlert>::iterator mi = mapAlerts.begin(); mi != mapAlerts.end();)
-        {
-            const CAlert& alert = (*mi).second;
-            if (Cancels(alert))
-            {
-                printf("cancelling alert %d\n", alert.nID);
-                mapAlerts.erase(mi++);
-            }
-            else if (!alert.IsInEffect())
-            {
-                printf("expiring alert %d\n", alert.nID);
-                mapAlerts.erase(mi++);
-            }
-            else
-                mi++;
-        }
-
-        // Check if this alert has been cancelled
-        BOOST_FOREACH(PAIRTYPE(const uint256, CAlert)& item, mapAlerts)
-        {
-            const CAlert& alert = item.second;
-            if (alert.Cancels(*this))
-            {
-                printf("alert already cancelled by %d\n", alert.nID);
-                return false;
-            }
-        }
-
-        // Add to mapAlerts
-        mapAlerts.insert(make_pair(GetHash(), *this));
-    }
-
-    printf("accepted alert %d, AppliesToMe()=%d\n", nID, AppliesToMe());
-    MainFrameRepaint();
-    return true;
-}
-
 
 
 
@@ -2631,22 +3310,20 @@ bool CAlert::ProcessAlert()
 //
 
 
-bool static AlreadyHave(CTxDB& txdb, const CInv& inv)
+bool static AlreadyHave(const CInv& inv)
 {
     switch (inv.type)
     {
     case MSG_TX:
         {
-        bool txInMap = false;
+            bool txInMap = false;
             {
-            LOCK(mempool.cs);
-            txInMap = (mempool.exists(inv.hash));
+                LOCK(mempool.cs);
+                txInMap = mempool.exists(inv.hash);
             }
-        return txInMap ||
-               mapOrphanTransactions.count(inv.hash) ||
-               txdb.ContainsTx(inv.hash);
+            return txInMap || mapOrphanTransactions.count(inv.hash) ||
+                pcoinsTip->HaveCoins(inv.hash);
         }
-
     case MSG_BLOCK:
         return mapBlockIndex.count(inv.hash) ||
                mapOrphanBlocks.count(inv.hash);
@@ -2658,24 +3335,23 @@ bool static AlreadyHave(CTxDB& txdb, const CInv& inv)
 
 
 
+// The message start string is designed to be unlikely to occur in normal data.
+// The characters are rarely used upper ASCII, not valid as UTF-8, and produce
+// a large 4-byte int at any alignment.
+unsigned char pchMessageStart[4] = { 0xe4, 0xe8, 0xe9, 0xe5 };
+
 bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
 {
-    static map<CService, vector<unsigned char> > mapReuseKey;
+    static map<CService, CPubKey> mapReuseKey;
     RandAddSeedPerfmon();
-    if (fDebug) {
-        printf("%s ", DateTimeStrFormat(GetTime()).c_str());
-        printf("received: %s (%d bytes)\n", strCommand.c_str(), vRecv.size());
-    }
+    if (fDebug)
+        printf("received: %s (%"PRIszu" bytes)\n", strCommand.c_str(), vRecv.size());
     if (mapArgs.count("-dropmessagestest") && GetRand(atoi(mapArgs["-dropmessagestest"])) == 0)
     {
         printf("dropmessagestest DROPPING RECV MESSAGE\n");
         return true;
     }
 
-
-
-
-
     if (strCommand == "version")
     {
         // Each connection can only send one version message
@@ -2708,6 +3384,12 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         if (!vRecv.empty())
             vRecv >> pfrom->nStartingHeight;
 
+        if (pfrom->fInbound && addrMe.IsRoutable())
+        {
+            pfrom->addrLocal = addrMe;
+            SeenLocal(addrMe);
+        }
+
         // Disconnect if we connected to ourself
         if (nNonce == nLocalHostNonce && nNonce > 1)
         {
@@ -2716,7 +3398,14 @@ 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;
 
@@ -2735,16 +3424,15 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         if (!pfrom->fInbound)
         {
             // Advertise our address
-            if (!fNoListen && !fUseProxy && addrLocalHost.IsRoutable() &&
-                !IsInitialBlockDownload())
+            if (!fNoListen && !IsInitialBlockDownload())
             {
-                CAddress addr(addrLocalHost);
-                addr.nTime = GetAdjustedTime();
-                pfrom->PushAddress(addr);
+                CAddress addr = GetLocalAddress(&pfrom->addr);
+                if (addr.IsRoutable())
+                    pfrom->PushAddress(addr);
             }
 
             // Get recent addresses
-            if (pfrom->nVersion >= CADDR_TIME_VERSION || addrman.size() < 1000)
+            if (pfrom->fOneShot || pfrom->nVersion >= CADDR_TIME_VERSION || addrman.size() < 1000)
             {
                 pfrom->PushMessage("getaddr");
                 pfrom->fGetAddr = true;
@@ -2760,7 +3448,8 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
 
         // Ask the first connected node for block updates
         static int nAskedForBlocks = 0;
-        if (!pfrom->fClient &&
+        if (!pfrom->fClient && !pfrom->fOneShot &&
+            (pfrom->nStartingHeight > (nBestHeight - 144)) &&
             (pfrom->nVersion < NOBLKS_VERSION_START ||
              pfrom->nVersion >= NOBLKS_VERSION_END) &&
              (nAskedForBlocks < 1 || vNodes.size() <= 1))
@@ -2776,7 +3465,7 @@ 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())
@@ -2785,7 +3474,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
 
         pfrom->fSuccessfullyConnected = true;
 
-        printf("version message: version %d, blocks=%d\n", pfrom->nVersion, pfrom->nStartingHeight);
+        printf("receive version message: version %d, blocks=%d, us=%s, them=%s, peer=%s\n", pfrom->nVersion, pfrom->nStartingHeight, addrMe.ToString().c_str(), addrFrom.ToString().c_str(), pfrom->addr.ToString().c_str());
 
         cPeerBlockCounts.input(pfrom->nStartingHeight);
 
@@ -2820,22 +3509,21 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         if (vAddr.size() > 1000)
         {
             pfrom->Misbehaving(20);
-            return error("message addr size() = %d", vAddr.size());
+            return error("message addr size() = %"PRIszu"", vAddr.size());
         }
 
         // Store the new addresses
+        vector<CAddress> vAddrOk;
         int64 nNow = GetAdjustedTime();
         int64 nSince = nNow - 10 * 60;
         BOOST_FOREACH(CAddress& addr, vAddr)
         {
             if (fShutdown)
                 return true;
-            // ignore IPv6 for now, since it isn't implemented anyway
-            if (!addr.IsIPv4())
-                continue;
             if (addr.nTime <= 100000000 || addr.nTime > nNow + 10 * 60)
                 addr.nTime = nNow - 5 * 24 * 60 * 60;
             pfrom->AddAddressKnown(addr);
+            bool fReachable = IsReachable(addr);
             if (addr.nTime > nSince && !pfrom->fGetAddr && vAddr.size() <= 10 && addr.IsRoutable())
             {
                 // Relay to a limited number of other nodes
@@ -2846,7 +3534,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
                     static uint256 hashSalt;
                     if (hashSalt == 0)
                         hashSalt = GetRandHash();
-                    int64 hashAddr = addr.GetHash();
+                    uint64 hashAddr = addr.GetHash();
                     uint256 hashRand = hashSalt ^ (hashAddr<<32) ^ ((GetTime()+hashAddr)/(24*60*60));
                     hashRand = Hash(BEGIN(hashRand), END(hashRand));
                     multimap<uint256, CNode*> mapMix;
@@ -2860,26 +3548,30 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
                         hashKey = Hash(BEGIN(hashKey), END(hashKey));
                         mapMix.insert(make_pair(hashKey, pnode));
                     }
-                    int nRelayNodes = 2;
+                    int nRelayNodes = fReachable ? 2 : 1; // limited relaying of addresses outside our network(s)
                     for (multimap<uint256, CNode*>::iterator mi = mapMix.begin(); mi != mapMix.end() && nRelayNodes-- > 0; ++mi)
                         ((*mi).second)->PushAddress(addr);
                 }
             }
+            // Do not store addresses outside our network
+            if (fReachable)
+                vAddrOk.push_back(addr);
         }
-        addrman.Add(vAddr, pfrom->addr, 2 * 60 * 60);
+        addrman.Add(vAddrOk, pfrom->addr, 2 * 60 * 60);
         if (vAddr.size() < 1000)
             pfrom->fGetAddr = false;
+        if (pfrom->fOneShot)
+            pfrom->fDisconnect = true;
     }
 
-
     else if (strCommand == "inv")
     {
         vector<CInv> vInv;
         vRecv >> vInv;
-        if (vInv.size() > 50000)
+        if (vInv.size() > MAX_INV_SZ)
         {
             pfrom->Misbehaving(20);
-            return error("message inv size() = %d", vInv.size());
+            return error("message inv size() = %"PRIszu"", vInv.size());
         }
 
         // find last block in inv vector
@@ -2890,7 +3582,6 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
                 break;
             }
         }
-        CTxDB txdb("r");
         for (unsigned int nInv = 0; nInv < vInv.size(); nInv++)
         {
             const CInv &inv = vInv[nInv];
@@ -2899,7 +3590,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
                 return true;
             pfrom->AddInventoryKnown(inv);
 
-            bool fAlreadyHave = AlreadyHave(txdb, inv);
+            bool fAlreadyHave = AlreadyHave(inv);
             if (fDebug)
                 printf("  got inventory: %s  %s\n", inv.ToString().c_str(), fAlreadyHave ? "have" : "new");
 
@@ -2911,7 +3602,6 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
                 // In case we are on a very long side-chain, it is possible that we already have
                 // the last block in an inv bundle sent in response to getblocks. Try to detect
                 // this situation and push another getblocks to continue.
-                std::vector<CInv> vGetData(1,inv);
                 pfrom->PushGetBlocks(mapBlockIndex[inv.hash], uint256(0));
                 if (fDebug)
                     printf("force request: %s\n", inv.ToString().c_str());
@@ -2927,17 +3617,21 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
     {
         vector<CInv> vInv;
         vRecv >> vInv;
-        if (vInv.size() > 50000)
+        if (vInv.size() > MAX_INV_SZ)
         {
             pfrom->Misbehaving(20);
-            return error("message getdata size() = %d", vInv.size());
+            return error("message getdata size() = %"PRIszu"", vInv.size());
         }
 
+        if (fDebugNet || (vInv.size() != 1))
+            printf("received getdata (%"PRIszu" invsz)\n", vInv.size());
+
         BOOST_FOREACH(const CInv& inv, vInv)
         {
             if (fShutdown)
                 return true;
-            printf("received getdata for: %s\n", inv.ToString().c_str());
+            if (fDebugNet || (vInv.size() == 1))
+                printf("received getdata for: %s\n", inv.ToString().c_str());
 
             if (inv.type == MSG_BLOCK)
             {
@@ -2952,9 +3646,6 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
                     // Trigger them to send a getblocks request for the next batch of inventory
                     if (inv.hash == pfrom->hashContinue)
                     {
-                        // Bypass PushInventory, this must send even if redundant,
-                        // and we want it right after the last block so they don't
-                        // wait for other stuff first.
                         // ppcoin: send latest proof-of-work block to allow the
                         // download node to accept as orphan (proof-of-stake 
                         // block might be rejected by stake connection check)
@@ -2968,11 +3659,24 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
             else if (inv.IsKnownType())
             {
                 // Send stream from relay memory
+                bool pushed = false;
                 {
                     LOCK(cs_mapRelay);
                     map<CInv, CDataStream>::iterator mi = mapRelay.find(inv);
-                    if (mi != mapRelay.end())
+                    if (mi != mapRelay.end()) {
                         pfrom->PushMessage(inv.GetCommand(), (*mi).second);
+                        pushed = true;
+                    }
+                }
+                if (!pushed && inv.type == MSG_TX) {
+                    LOCK(mempool.cs);
+                    if (mempool.exists(inv.hash)) {
+                        CTransaction tx = mempool.lookup(inv.hash);
+                        CDataStream ss(SER_NETWORK, PROTOCOL_VERSION);
+                        ss.reserve(1000);
+                        ss << tx;
+                        pfrom->PushMessage("tx", ss);
+                    }
                 }
             }
 
@@ -2994,14 +3698,13 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         // Send the rest of the chain
         if (pindex)
             pindex = pindex->pnext;
-        int nLimit = 500 + locator.GetDistanceBack();
-        unsigned int nBytes = 0;
+        int nLimit = 500;
         printf("getblocks %d to %s limit %d\n", (pindex ? pindex->nHeight : -1), hashStop.ToString().substr(0,20).c_str(), nLimit);
         for (; pindex; pindex = pindex->pnext)
         {
             if (pindex->GetBlockHash() == hashStop)
             {
-                printf("  getblocks stopping at %d %s (%u bytes)\n", pindex->nHeight, pindex->GetBlockHash().ToString().substr(0,20).c_str(), nBytes);
+                printf("  getblocks stopping at %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString().substr(0,20).c_str());
                 // ppcoin: tell downloading node about the latest block if it's
                 // without risk being rejected due to stake connection check
                 if (hashStop != hashBestChain && pindex->GetBlockTime() + nStakeMinAge > pindexBest->GetBlockTime())
@@ -3009,20 +3712,30 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
                 break;
             }
             pfrom->PushInventory(CInv(MSG_BLOCK, pindex->GetBlockHash()));
-            CBlock block;
-            block.ReadFromDisk(pindex, true);
-            nBytes += block.GetSerializeSize(SER_NETWORK, PROTOCOL_VERSION);
-            if (--nLimit <= 0 || nBytes >= SendBufferSize()/2)
+            if (--nLimit <= 0)
             {
                 // When this block is requested, we'll send an inv that'll make them
                 // getblocks the next batch of inventory.
-                printf("  getblocks stopping at limit %d %s (%u bytes)\n", pindex->nHeight, pindex->GetBlockHash().ToString().substr(0,20).c_str(), nBytes);
+                printf("  getblocks stopping at limit %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString().substr(0,20).c_str());
                 pfrom->hashContinue = pindex->GetBlockHash();
                 break;
             }
         }
     }
+    else if (strCommand == "checkpoint")
+    {
+        CSyncCheckpoint checkpoint;
+        vRecv >> checkpoint;
 
+        if (checkpoint.ProcessSyncCheckpoint(pfrom))
+        {
+            // Relay
+            pfrom->hashCheckpointKnown = checkpoint.hashCheckpoint;
+            LOCK(cs_vNodes);
+            BOOST_FOREACH(CNode* pnode, vNodes)
+                checkpoint.RelayTo(pnode);
+        }
+    }
 
     else if (strCommand == "getheaders")
     {
@@ -3065,7 +3778,6 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         vector<uint256> vWorkQueue;
         vector<uint256> vEraseQueue;
         CDataStream vMsg(vRecv);
-        CTxDB txdb("r");
         CTransaction tx;
         vRecv >> tx;
 
@@ -3073,10 +3785,10 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         pfrom->AddInventoryKnown(inv);
 
         bool fMissingInputs = false;
-        if (tx.AcceptToMemoryPool(txdb, true, &fMissingInputs))
+        if (tx.AcceptToMemoryPool(true, &fMissingInputs))
         {
-            SyncWithWallets(tx, NULL, true);
-            RelayMessage(inv, vMsg);
+            SyncWithWallets(inv.hash, tx, NULL, true);
+            RelayTransaction(tx, inv.hash);
             mapAlreadyAskedFor.erase(inv);
             vWorkQueue.push_back(inv.hash);
             vEraseQueue.push_back(inv.hash);
@@ -3085,30 +3797,28 @@ 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(true, &fMissingInputs2))
                     {
-                        printf("   accepted orphan tx %s\n", inv.hash.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);
+                        printf("   accepted orphan tx %s\n", orphanTxHash.ToString().substr(0,10).c_str());
+                        SyncWithWallets(inv.hash, tx, NULL, true);
+                        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());
                     }
                 }
             }
@@ -3118,7 +3828,7 @@ 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);
@@ -3133,11 +3843,12 @@ 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))
@@ -3148,10 +3859,29 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
 
     else if (strCommand == "getaddr")
     {
+        // Don't return addresses older than nCutOff timestamp
+        int64 nCutOff = GetTime() - (nNodeLifespan * 24 * 60 * 60);
         pfrom->vAddrToSend.clear();
         vector<CAddress> vAddr = addrman.GetAddr();
         BOOST_FOREACH(const CAddress &addr, vAddr)
-            pfrom->PushAddress(addr);
+            if(addr.nTime > nCutOff)
+                pfrom->PushAddress(addr);
+    }
+
+
+    else if (strCommand == "mempool")
+    {
+        std::vector<uint256> vtxid;
+        mempool.queryHashes(vtxid);
+        vector<CInv> vInv;
+        for (unsigned int i = 0; i < vtxid.size(); i++) {
+            CInv inv(MSG_TX, vtxid[i]);
+            vInv.push_back(inv);
+            if (i == (MAX_INV_SZ - 1))
+                    break;
+        }
+        if (vInv.size() > 0)
+            pfrom->PushMessage("inv", vInv);
     }
 
 
@@ -3229,32 +3959,31 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         CAlert alert;
         vRecv >> alert;
 
-        if (alert.ProcessAlert())
+        uint256 alertHash = alert.GetHash();
+        if (pfrom->setKnown.count(alertHash) == 0)
         {
-            // Relay
-            pfrom->setKnown.insert(alert.GetHash());
+            if (alert.ProcessAlert())
             {
-                LOCK(cs_vNodes);
-                BOOST_FOREACH(CNode* pnode, vNodes)
-                    alert.RelayTo(pnode);
+                // Relay
+                pfrom->setKnown.insert(alertHash);
+                {
+                    LOCK(cs_vNodes);
+                    BOOST_FOREACH(CNode* pnode, vNodes)
+                        alert.RelayTo(pnode);
+                }
+            }
+            else {
+                // Small DoS penalty so peers that send us lots of
+                // duplicate/expired/invalid-signature/whatever alerts
+                // eventually get banned.
+                // This isn't a Misbehaving(100) (immediate ban) because the
+                // peer might be an older or different implementation with
+                // a different signature key, etc.
+                pfrom->Misbehaving(10);
             }
         }
     }
 
-    else if (strCommand == "checkpoint")
-    {
-        CSyncCheckpoint checkpoint;
-        vRecv >> checkpoint;
-
-        if (checkpoint.ProcessSyncCheckpoint(pfrom))
-        {
-            // Relay
-            pfrom->hashCheckpointKnown = checkpoint.hashCheckpoint;
-            LOCK(cs_vNodes);
-            BOOST_FOREACH(CNode* pnode, vNodes)
-                checkpoint.RelayTo(pnode);
-        }
-    }
 
     else
     {
@@ -3288,19 +4017,12 @@ bool ProcessMessages(CNode* pfrom)
     //  (x) data
     //
 
-    unsigned char pchMessageStart[4];
-    GetMessageStart(pchMessageStart);
-    static int64 nTimeLastPrintMessageStart = 0;
-    if (fDebug && GetBoolArg("-printmessagestart") && nTimeLastPrintMessageStart + 30 < GetAdjustedTime())
+    while (true)
     {
-        string strMessageStart((const char *)pchMessageStart, sizeof(pchMessageStart));
-        vector<unsigned char> vchMessageStart(strMessageStart.begin(), strMessageStart.end());
-        printf("ProcessMessages : AdjustedTime=%"PRI64d" MessageStart=%s\n", GetAdjustedTime(), HexStr(vchMessageStart).c_str());
-        nTimeLastPrintMessageStart = GetAdjustedTime();
-    }
+        // Don't bother if send buffer is too full to respond anyway
+        if (pfrom->vSend.size() >= SendBufferSize())
+            break;
 
-    loop
-    {
         // Scan for message start
         CDataStream::iterator pstart = search(vRecv.begin(), vRecv.end(), BEGIN(pchMessageStart), END(pchMessageStart));
         int nHeaderSize = vRecv.GetSerializeSize(CMessageHeader());
@@ -3314,7 +4036,7 @@ bool ProcessMessages(CNode* pfrom)
             break;
         }
         if (pstart - vRecv.begin() > 0)
-            printf("\n\nPROCESSMESSAGE SKIPPED %d BYTES\n\n", pstart - vRecv.begin());
+            printf("\n\nPROCESSMESSAGE SKIPPED %"PRIpdd" BYTES\n\n", pstart - vRecv.begin());
         vRecv.erase(vRecv.begin(), pstart);
 
         // Read header
@@ -3372,12 +4094,12 @@ bool ProcessMessages(CNode* pfrom)
         {
             if (strstr(e.what(), "end of data"))
             {
-                // Allow exceptions from underlength message on vRecv
+                // Allow exceptions from under-length message on vRecv
                 printf("ProcessMessages(%s, %u bytes) : Exception '%s' caught, normally caused by a message being shorter than its stated length\n", strCommand.c_str(), nMessageSize, e.what());
             }
             else if (strstr(e.what(), "size too large"))
             {
-                // Allow exceptions from overlong size
+                // Allow exceptions from over-long size
                 printf("ProcessMessages(%s, %u bytes) : Exception '%s' caught\n", strCommand.c_str(), nMessageSize, e.what());
             }
             else
@@ -3434,11 +4156,11 @@ bool SendMessages(CNode* pto, bool fSendTrickle)
                         pnode->setAddrKnown.clear();
 
                     // Rebroadcast our address
-                    if (!fNoListen && !fUseProxy && addrLocalHost.IsRoutable())
+                    if (!fNoListen)
                     {
-                        CAddress addr(addrLocalHost);
-                        addr.nTime = GetAdjustedTime();
-                        pnode->PushAddress(addr);
+                        CAddress addr = GetLocalAddress(&pnode->addr);
+                        if (addr.IsRoutable())
+                            pnode->PushAddress(addr);
                     }
                 }
             }
@@ -3535,21 +4257,21 @@ bool SendMessages(CNode* pto, bool fSendTrickle)
         //
         vector<CInv> vGetData;
         int64 nNow = GetTime() * 1000000;
-        CTxDB txdb("r");
         while (!pto->mapAskFor.empty() && (*pto->mapAskFor.begin()).first <= nNow)
         {
             const CInv& inv = (*pto->mapAskFor.begin()).second;
-            if (!AlreadyHave(txdb, inv))
+            if (!AlreadyHave(inv))
             {
-                printf("sending getdata: %s\n", inv.ToString().c_str());
+                if (fDebugNet)
+                    printf("sending getdata: %s\n", inv.ToString().c_str());
                 vGetData.push_back(inv);
                 if (vGetData.size() >= 1000)
                 {
                     pto->PushMessage("getdata", vGetData);
                     vGetData.clear();
                 }
+                mapAlreadyAskedFor[inv] = nNow;
             }
-            mapAlreadyAskedFor[inv] = nNow;
             pto->mapAskFor.erase(pto->mapAskFor.begin());
         }
         if (!vGetData.empty())
@@ -3559,635 +4281,56 @@ bool SendMessages(CNode* pto, bool fSendTrickle)
     return true;
 }
 
+// Amount compression:
+// * If the amount is 0, output 0
+// * first, divide the amount (in base units) by the largest power of 10 possible; call the exponent e (e is max 9)
+// * if e<9, the last digit of the resulting number cannot be 0; store it as d, and drop it (divide by 10)
+//   * call the result n
+//   * output 1 + 10*(9*n + d - 1) + e
+// * if e==9, we only know the resulting number is not zero, so output 1 + 10*(n - 1) + 9
+// (this is decodable, as d is in [1-9] and e is in [0-9])
 
-
-
-
-
-
-
-
-
-
-
-
-
-//////////////////////////////////////////////////////////////////////////////
-//
-// 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;
-
-    COrphan(CTransaction* ptxIn)
-    {
-        ptx = ptxIn;
-        dPriority = 0;
-    }
-
-    void print() const
-    {
-        printf("COrphan(hash=%s, dPriority=%.1f)\n", ptx->GetHash().ToString().substr(0,10).c_str(), dPriority);
-        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;
-
-// CreateNewBlock:
-//   fProofOfStake: try (best effort) to make a proof-of-stake block
-CBlock* CreateNewBlock(CWallet* pwallet, bool fProofOfStake)
-{
-    CReserveKey reservekey(pwallet);
-
-    // 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);
-    txNew.vout[0].scriptPubKey << reservekey.GetReservedKey() << OP_CHECKSIG;
-
-    // Add our coinbase tx as first transaction
-    pblock->vtx.push_back(txNew);
-
-    // ppcoin: if coinstake available add coinstake tx
-    static int64 nLastCoinStakeSearchTime = GetAdjustedTime();  // only initialized at startup
-    CBlockIndex* pindexPrev = pindexBest;
-
-    if (fProofOfStake)  // attemp 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].vout[0].SetEmpty();
-                    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);
-        CTxDB txdb("r");
-
-        // Priority order to process transactions
-        list<COrphan> vOrphan; // list memory doesn't move
-        map<uint256, vector<COrphan*> > mapDependers;
-        multimap<double, CTransaction*> mapPriority;
-        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;
-            BOOST_FOREACH(const CTxIn& txin, tx.vin)
-            {
-                // Read prev transaction
-                CTransaction txPrev;
-                CTxIndex txindex;
-                if (!txPrev.ReadFromDisk(txdb, txin.prevout, txindex))
-                {
-                    // 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);
-                    continue;
-                }
-                int64 nValueIn = txPrev.vout[txin.prevout.n].nValue;
-
-                // Read block header
-                int nConf = txindex.GetDepthInMainChain();
-
-                dPriority += (double)nValueIn * nConf;
-
-                if (fDebug && GetBoolArg("-printpriority"))
-                    printf("priority     nValueIn=%-12"PRI64d" nConf=%-5d dPriority=%-20.1f\n", nValueIn, nConf, dPriority);
-            }
-
-            // Priority is sum(valuein * age) / txsize
-            dPriority /= ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
-
-            if (porphan)
-                porphan->dPriority = dPriority;
-            else
-                mapPriority.insert(make_pair(-dPriority, &(*mi).second));
-
-            if (fDebug && GetBoolArg("-printpriority"))
-            {
-                printf("priority %-20.1f %s\n%s", dPriority, tx.GetHash().ToString().substr(0,10).c_str(), tx.ToString().c_str());
-                if (porphan)
-                    porphan->print();
-                printf("\n");
-            }
-        }
-
-        // Collect transactions into block
-        map<uint256, CTxIndex> mapTestPool;
-        uint64 nBlockSize = 1000;
-        uint64 nBlockTx = 0;
-        int nBlockSigOps = 100;
-        while (!mapPriority.empty())
-        {
-            // Take highest priority transaction off priority queue
-            CTransaction& tx = *(*mapPriority.begin()).second;
-            mapPriority.erase(mapPriority.begin());
-
-            // Size limits
-            unsigned int nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
-            if (nBlockSize + nTxSize >= MAX_BLOCK_SIZE_GEN)
-                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);
-
-            // 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;
-
-            // 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())
-                            mapPriority.insert(make_pair(-porphan->dPriority, porphan->ptx));
-                    }
-                }
-            }
-        }
-
-        nLastBlockTx = nBlockTx;
-        nLastBlockSize = nBlockSize;
-        if (fDebug && GetBoolArg("-printpriority"))
-            printf("CreateNewBlock(): total size %lu\n", nBlockSize);
-
-    }
-    if (pblock->IsProofOfWork())
-        pblock->vtx[0].vout[0].nValue = GetProofOfWorkReward(pblock->nBits);
-
-    // Fill in header
-    pblock->hashPrevBlock  = pindexPrev->GetBlockHash();
-    pblock->hashMerkleRoot = pblock->BuildMerkleTree();
-    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)
+uint64 CTxOutCompressor::CompressAmount(uint64 n)
 {
-    // Update nExtraNonce
-    static uint256 hashPrevBlock;
-    if (hashPrevBlock != pblock->hashPrevBlock)
-    {
-        nExtraNonce = 0;
-        hashPrevBlock = pblock->hashPrevBlock;
+    if (n == 0)
+        return 0;
+    int e = 0;
+    while (((n % 10) == 0) && e < 9) {
+        n /= 10;
+        e++;
     }
-    ++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)
-{
-    //
-    // Prebuild 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];
+    if (e < 9) {
+        int d = (n % 10);
+        assert(d >= 1 && d <= 9);
+        n /= 10;
+        return 1 + (n*9 + d - 1)*10 + e;
+    } else {
+        return 1 + (n - 1)*10 + 9;
     }
-    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 (hash > hashTarget && pblock->IsProofOfWork())
-        return error("BitcoinMiner : proof-of-work not meeting target");
-
-    //// debug print
-    printf("BitcoinMiner:\n");
-    printf("new block found  \n  hash: %s  \ntarget: %s\n", hash.GetHex().c_str(), hashTarget.GetHex().c_str());
-    pblock->print();
-    printf("%s ", DateTimeStrFormat(GetTime()).c_str());
-    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("BitcoinMiner : 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("BitcoinMiner : ProcessBlock, block not accepted");
-    }
-
-    return true;
 }
 
-void static ThreadBitcoinMiner(void* parg);
-
-static bool fGenerateBitcoins = false;
-static bool fLimitProcessors = false;
-static int nLimitProcessors = -1;
-
-void BitcoinMiner(CWallet *pwallet, bool fProofOfStake)
+uint64 CTxOutCompressor::DecompressAmount(uint64 x)
 {
-    void *scratchbuf = scrypt_buffer_alloc();
-
-    printf("CPUMiner started for proof-of-%s\n", fProofOfStake? "stake" : "work");
-    SetThreadPriority(THREAD_PRIORITY_LOWEST);
-
-    // Each thread has its own key and counter
-    CReserveKey reservekey(pwallet);
-    unsigned int nExtraNonce = 0;
-
-    while (fGenerateBitcoins || fProofOfStake)
-    {
-        if (fShutdown)
-            return;
-        while (vNodes.empty() || IsInitialBlockDownload())
-        {
-            Sleep(1000);
-            if (fShutdown)
-                return;
-            if ((!fGenerateBitcoins) && !fProofOfStake)
-                return;
-        }
-
-        while (pwallet->IsLocked())
-        {
-            strMintWarning = strMintMessage;
-            Sleep(1000);
-        }
-        strMintWarning = "";
-
-        //
-        // Create new block
-        //
-        unsigned int nTransactionsUpdatedLast = nTransactionsUpdated;
-        CBlockIndex* pindexPrev = pindexBest;
-
-        auto_ptr<CBlock> pblock(CreateNewBlock(pwallet, fProofOfStake));
-        if (!pblock.get())
-            return;
-
-        IncrementExtraNonce(pblock.get(), pindexPrev, nExtraNonce);
-
-        if (fProofOfStake)
-        {
-            // ppcoin: if proof-of-stake block found then process block
-            if (pblock->IsProofOfStake())
-            {
-                if (!pblock->SignBlock(*pwalletMain))
-                {
-                    strMintWarning = strMintMessage;
-                    continue;
-                }
-                strMintWarning = "";
-                printf("CPUMiner : proof-of-stake block found %s\n", pblock->GetHash().ToString().c_str()); 
-                SetThreadPriority(THREAD_PRIORITY_NORMAL);
-                CheckWork(pblock.get(), *pwalletMain, reservekey);
-                SetThreadPriority(THREAD_PRIORITY_LOWEST);
-            }
-            Sleep(500);
-            continue;
-        }
-
-        printf("Running BitcoinMiner with %d transactions in block\n", pblock->vtx.size());
-
-
-        //
-        // Prebuild hash buffers
-        //
-        char pmidstatebuf[32+16]; char* pmidstate = alignup<16>(pmidstatebuf);
-        char pdatabuf[128+16];    char* pdata     = alignup<16>(pdatabuf);
-        char phash1buf[64+16];    char* phash1    = alignup<16>(phash1buf);
-
-        FormatHashBuffers(pblock.get(), pmidstate, pdata, phash1);
-
-        unsigned int& nBlockTime = *(unsigned int*)(pdata + 64 + 4);
-        unsigned int& nBlockNonce = *(unsigned int*)(pdata + 64 + 12);
-
-
-        //
-        // Search
-        //
-        int64 nStart = GetTime();
-        uint256 hashTarget = CBigNum().SetCompact(pblock->nBits).getuint256();
-
-        unsigned int max_nonce = 0xffff0000;
-        block_header res_header;
-        uint256 result;
-
-        loop
-        {
-            unsigned int nHashesDone = 0;
-            unsigned int nNonceFound;
-
-            nNonceFound = scanhash_scrypt(
-                        (block_header *)&pblock->nVersion,
-                        scratchbuf,
-                        max_nonce,
-                        nHashesDone,
-                        UBEGIN(result),
-                        &res_header
-            );
-
-            // Check if something found
-            if (nNonceFound != (unsigned int) -1)
-            {
-                if (result <= hashTarget)
-                {
-                    // Found a solution
-                    pblock->nNonce = nNonceFound;
-                    assert(result == pblock->GetHash());
-                    if (!pblock->SignBlock(*pwalletMain))
-                    {
-                        strMintWarning = strMintMessage;
-                        break;
-                    }
-                    strMintWarning = "";
-                    SetThreadPriority(THREAD_PRIORITY_NORMAL);
-                    CheckWork(pblock.get(), *pwalletMain, reservekey);
-                    SetThreadPriority(THREAD_PRIORITY_LOWEST);
-                    break;
-                }
-            }
-
-            // Meter hashes/sec
-            static int64 nHashCounter;
-            if (nHPSTimerStart == 0)
-            {
-                nHPSTimerStart = GetTimeMillis();
-                nHashCounter = 0;
-            }
-            else
-                nHashCounter += nHashesDone;
-            if (GetTimeMillis() - nHPSTimerStart > 4000)
-            {
-                static CCriticalSection cs;
-                {
-                    LOCK(cs);
-                    if (GetTimeMillis() - nHPSTimerStart > 4000)
-                    {
-                        dHashesPerSec = 1000.0 * nHashCounter / (GetTimeMillis() - nHPSTimerStart);
-                        nHPSTimerStart = GetTimeMillis();
-                        nHashCounter = 0;
-                        static int64 nLogTime;
-                        if (GetTime() - nLogTime > 30 * 60)
-                        {
-                            nLogTime = GetTime();
-                            printf("%s ", DateTimeStrFormat(GetTime()).c_str());
-                            printf("hashmeter %3d CPUs %6.0f khash/s\n", vnThreadsRunning[THREAD_MINER], dHashesPerSec/1000.0);
-                        }
-                    }
-                }
-            }
-
-            // Check for stop or if block needs to be rebuilt
-            if (fShutdown)
-                return;
-            if (!fGenerateBitcoins)
-                return;
-            if (fLimitProcessors && vnThreadsRunning[THREAD_MINER] > nLimitProcessors)
-                return;
-            if (vNodes.empty())
-                break;
-            if (nBlockNonce >= 0xffff0000)
-                break;
-            if (nTransactionsUpdated != nTransactionsUpdatedLast && GetTime() - nStart > 60)
-                break;
-            if (pindexPrev != pindexBest)
-                break;
-
-            // Update nTime every few seconds
-            pblock->nTime = max(pindexPrev->GetMedianTimePast()+1, pblock->GetMaxTransactionTime());
-            pblock->nTime = max(pblock->GetBlockTime(), pindexPrev->GetBlockTime() - nMaxClockDrift);
-            pblock->UpdateTime(pindexPrev);
-            nBlockTime = ByteReverse(pblock->nTime);
-            if (pblock->GetBlockTime() >= (int64)pblock->vtx[0].nTime + nMaxClockDrift)
-                break;  // need to update coinbase timestamp
-        }
+    // x = 0  OR  x = 1+10*(9*n + d - 1) + e  OR  x = 1+10*(n - 1) + 9
+    if (x == 0)
+        return 0;
+    x--;
+    // x = 10*(9*n + d - 1) + e
+    int e = x % 10;
+    x /= 10;
+    uint64 n = 0;
+    if (e < 9) {
+        // x = 9*n + d - 1
+        int d = (x % 9) + 1;
+        x /= 9;
+        // x = n
+        n = x*10 + d;
+    } else {
+        n = x+1;
     }
-
-    scrypt_buffer_free(scratchbuf);
-}
-
-void static ThreadBitcoinMiner(void* parg)
-{
-    CWallet* pwallet = (CWallet*)parg;
-    try
-    {
-        vnThreadsRunning[THREAD_MINER]++;
-        BitcoinMiner(pwallet, false);
-        vnThreadsRunning[THREAD_MINER]--;
-    }
-    catch (std::exception& e) {
-        vnThreadsRunning[THREAD_MINER]--;
-        PrintException(&e, "ThreadBitcoinMiner()");
-    } catch (...) {
-        vnThreadsRunning[THREAD_MINER]--;
-        PrintException(NULL, "ThreadBitcoinMiner()");
-    }
-    nHPSTimerStart = 0;
-    if (vnThreadsRunning[THREAD_MINER] == 0)
-        dHashesPerSec = 0;
-    printf("ThreadBitcoinMiner exiting, %d threads remaining\n", vnThreadsRunning[THREAD_MINER]);
-}
-
-
-void GenerateBitcoins(bool fGenerate, CWallet* pwallet)
-{
-    fGenerateBitcoins = fGenerate;
-    nLimitProcessors = GetArg("-genproclimit", -1);
-    if (nLimitProcessors == 0)
-        fGenerateBitcoins = false;
-    fLimitProcessors = (nLimitProcessors != -1);
-
-    if (fGenerate)
-    {
-        int nProcessors = boost::thread::hardware_concurrency();
-        printf("%d processors\n", nProcessors);
-        if (nProcessors < 1)
-            nProcessors = 1;
-        if (fLimitProcessors && nProcessors > nLimitProcessors)
-            nProcessors = nLimitProcessors;
-        int nAddThreads = nProcessors - vnThreadsRunning[THREAD_MINER];
-        printf("Starting %d BitcoinMiner threads\n", nAddThreads);
-        for (int i = 0; i < nAddThreads; i++)
-        {
-            if (!CreateThread(ThreadBitcoinMiner, pwallet))
-                printf("Error: CreateThread(ThreadBitcoinMiner) failed\n");
-            Sleep(10);
-        }
+    while (e) {
+        n *= 10;
+        e--;
     }
+    return n;
 }