Merge pull request #2632 from mikehearn/chainparams

Refactor chain-specific tweaks into a CChainParams class and introduce a regtest mode

27 files changed, 638 insertions, 658 deletions

diff --git a/bitcoin-qt.pro b/bitcoin-qt.pro
index 8f49dccee3..1d62941e68 100644
--- a/bitcoin-qt.pro
+++ b/bitcoin-qt.pro
@@ -147,6 +147,7 @@ HEADERS += src/qt/bitcoingui.h \
     src/addrman.h \
     src/base58.h \
     src/bignum.h \
+    src/chainparams.h \
     src/checkpoints.h \
     src/compat.h \
     src/sync.h \
@@ -227,6 +228,7 @@ SOURCES += src/qt/bitcoin.cpp \
     src/qt/editaddressdialog.cpp \
     src/qt/bitcoinaddressvalidator.cpp \
     src/alert.cpp \
+    src/chainparams.cpp \
     src/version.cpp \
     src/sync.cpp \
     src/util.cpp \
diff --git a/contrib/test-patches/bitcoind-comparison.patch b/contrib/test-patches/bitcoind-comparison.patch
deleted file mode 100644
index f82b102e2a..0000000000
--- a/contrib/test-patches/bitcoind-comparison.patch
+++ /dev/null
@@ -1,196 +0,0 @@
-diff --git a/contrib/test-patches/bitcoind-comparison.patch b/contrib/test-patches/bitcoind-comparison.patch
-index 04a8618..519429a 100644
---- a/src/main.cpp
-+++ b/src/main.cpp
-@@ -31,8 +31,8 @@ CTxMemPool mempool;
- 
- map<uint256, CBlockIndex*> mapBlockIndex;
- std::vector<CBlockIndex*> vBlockIndexByHeight;
--uint256 hashGenesisBlock("0x000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f");
--static CBigNum bnProofOfWorkLimit(~uint256(0) >> 32);
-+uint256 hashGenesisBlock("0x0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206");
-+static CBigNum bnProofOfWorkLimit(~uint256(0) >> 1);
- CBlockIndex* pindexGenesisBlock = NULL;
- int nBestHeight = -1;
- uint256 nBestChainWork = 0;
-@@ -1055,7 +1055,7 @@ int64 static GetBlockValue(int nHeight, int64 nFees)
-     int64 nSubsidy = 50 * COIN;
- 
-     // Subsidy is cut in half every 210000 blocks, which will occur approximately every 4 years
--    nSubsidy >>= (nHeight / 210000);
-+    nSubsidy >>= (nHeight / 150);
- 
-     return nSubsidy + nFees;
- }
-@@ -2736,9 +2736,9 @@ bool InitBlockIndex() {
-         block.hashPrevBlock = 0;
-         block.hashMerkleRoot = block.BuildMerkleTree();
-         block.nVersion = 1;
--        block.nTime    = 1231006505;
--        block.nBits    = 0x1d00ffff;
--        block.nNonce   = 2083236893;
-+        block.nTime    = 1296688602;
-+        block.nBits    = 0x207fffff;
-+        block.nNonce   = 2;
- 
-         if (fTestNet)
-         {
-@@ -3024,7 +3024,7 @@ bool static AlreadyHave(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] = { 0xf9, 0xbe, 0xb4, 0xd9 };
-+unsigned char pchMessageStart[4] = { 0xfa, 0xbf, 0xb5, 0xda };
- 
- 
- void static ProcessGetData(CNode* pfrom)
-diff --git a/src/test/miner_tests.cpp b/src/test/miner_tests.cpp
-index af28465..ee9a4db 100644
---- a/src/test/miner_tests.cpp
-+++ b/src/test/miner_tests.cpp
-@@ -15,34 +15,117 @@ struct {
-     unsigned char extranonce;
-     unsigned int nonce;
- } blockinfo[] = {
--    {4, 0xa4a3e223}, {2, 0x15c32f9e}, {1, 0x0375b547}, {1, 0x7004a8a5},
--    {2, 0xce440296}, {2, 0x52cfe198}, {1, 0x77a72cd0}, {2, 0xbb5d6f84},
--    {2, 0x83f30c2c}, {1, 0x48a73d5b}, {1, 0xef7dcd01}, {2, 0x6809c6c4},
--    {2, 0x0883ab3c}, {1, 0x087bbbe2}, {2, 0x2104a814}, {2, 0xdffb6daa},
--    {1, 0xee8a0a08}, {2, 0xba4237c1}, {1, 0xa70349dc}, {1, 0x344722bb},
--    {3, 0xd6294733}, {2, 0xec9f5c94}, {2, 0xca2fbc28}, {1, 0x6ba4f406},
--    {2, 0x015d4532}, {1, 0x6e119b7c}, {2, 0x43e8f314}, {2, 0x27962f38},
--    {2, 0xb571b51b}, {2, 0xb36bee23}, {2, 0xd17924a8}, {2, 0x6bc212d9},
--    {1, 0x630d4948}, {2, 0x9a4c4ebb}, {2, 0x554be537}, {1, 0xd63ddfc7},
--    {2, 0xa10acc11}, {1, 0x759a8363}, {2, 0xfb73090d}, {1, 0xe82c6a34},
--    {1, 0xe33e92d7}, {3, 0x658ef5cb}, {2, 0xba32ff22}, {5, 0x0227a10c},
--    {1, 0xa9a70155}, {5, 0xd096d809}, {1, 0x37176174}, {1, 0x830b8d0f},
--    {1, 0xc6e3910e}, {2, 0x823f3ca8}, {1, 0x99850849}, {1, 0x7521fb81},
--    {1, 0xaacaabab}, {1, 0xd645a2eb}, {5, 0x7aea1781}, {5, 0x9d6e4b78},
--    {1, 0x4ce90fd8}, {1, 0xabdc832d}, {6, 0x4a34f32a}, {2, 0xf2524c1c},
--    {2, 0x1bbeb08a}, {1, 0xad47f480}, {1, 0x9f026aeb}, {1, 0x15a95049},
--    {2, 0xd1cb95b2}, {2, 0xf84bbda5}, {1, 0x0fa62cd1}, {1, 0xe05f9169},
--    {1, 0x78d194a9}, {5, 0x3e38147b}, {5, 0x737ba0d4}, {1, 0x63378e10},
--    {1, 0x6d5f91cf}, {2, 0x88612eb8}, {2, 0xe9639484}, {1, 0xb7fabc9d},
--    {2, 0x19b01592}, {1, 0x5a90dd31}, {2, 0x5bd7e028}, {2, 0x94d00323},
--    {1, 0xa9b9c01a}, {1, 0x3a40de61}, {1, 0x56e7eec7}, {5, 0x859f7ef6},
--    {1, 0xfd8e5630}, {1, 0x2b0c9f7f}, {1, 0xba700e26}, {1, 0x7170a408},
--    {1, 0x70de86a8}, {1, 0x74d64cd5}, {1, 0x49e738a1}, {2, 0x6910b602},
--    {0, 0x643c565f}, {1, 0x54264b3f}, {2, 0x97ea6396}, {2, 0x55174459},
--    {2, 0x03e8779a}, {1, 0x98f34d8f}, {1, 0xc07b2b07}, {1, 0xdfe29668},
--    {1, 0x3141c7c1}, {1, 0xb3b595f4}, {1, 0x735abf08}, {5, 0x623bfbce},
--    {2, 0xd351e722}, {1, 0xf4ca48c9}, {1, 0x5b19c670}, {1, 0xa164bf0e},
--    {2, 0xbbbeb305}, {2, 0xfe1c810a},
-+{4, 2762203683},
-+{2, 365113248},
-+{1, 58045772},
-+{1, 1879353512},
-+{2, 3460563607},
-+{2, 1389355416},
-+{1, 2007444690},
-+{2, 3143462790},
-+{2, 2213743660},
-+{1, 1218919771},
-+{1, 4017999107},
-+{2, 1745471173},
-+{2, 142846780},
-+{1, 142326754},
-+{2, 553953301},
-+{2, 3757796778},
-+{1, 4002023946},
-+{2, 3124901826},
-+{1, 2802010589},
-+{1, 877077181},
-+{3, 3593029427},
-+{2, 3969866902},
-+{2, 3392125996},
-+{1, 1805972490},
-+{2, 22889779},
-+{1, 1846647676},
-+{2, 1139340052},
-+{2, 664153912},
-+{2, 3044128027},
-+{2, 3010194979},
-+{2, 3514377385},
-+{2, 1807880922},
-+{1, 1661815113},
-+{2, 2588692156},
-+{2, 1431037239},
-+{1, 3594379210},
-+{2, 2701839377},
-+{1, 1973060452},
-+{2, 4218620174},
-+{1, 3895224884},
-+{1, 3812528857},
-+{3, 1703867851},
-+{2, 3123904294},
-+{5, 36151564},
-+{1, 2846294357},
-+{5, 3499546633},
-+{1, 924279160},
-+{1, 2198572304},
-+{1, 3336802574},
-+{2, 2185182379},
-+{1, 2575632458},
-+{1, 1965161345},
-+{1, 2865408940},
-+{1, 3594887915},
-+{5, 2062161796},
-+{5, 2641251194},
-+{1, 1290342362},
-+{1, 2883355438},
-+{6, 1244984107},
-+{2, 4065479712},
-+{2, 465481866},
-+{1, 2907174016},
-+{1, 2667735788},
-+{1, 363417673},
-+{2, 3519780275},
-+{2, 4165713317},
-+{1, 262548689},
-+{1, 3764359529},
-+{1, 2027001003},
-+{5, 1043862655},
-+{5, 1937481940},
-+{1, 1664585233},
-+{1, 1834979792},
-+{2, 2288070330},
-+{2, 3915617412},
-+{1, 3086662813},
-+{2, 430970259},
-+{1, 1519443249},
-+{2, 1540874280},
-+{2, 2496660261},
-+{1, 2847522842},
-+{1, 977329763},
-+{1, 1458040519},
-+{5, 2241822454},
-+{1, 4253963824},
-+{1, 722247551},
-+{1, 3127905834},
-+{1, 1903207432},
-+{1, 1893631657},
-+{1, 1960201429},
-+{1, 1239890082},
-+{2, 1762702850},
-+{0, 1681675873},
-+{1, 1411795775},
-+{2, 2548720534},
-+{2, 1427588186},
-+{2, 65566621},
-+{1, 2566081936},
-+{1, 3229297415},
-+{1, 3756168812},
-+{1, 826394561},
-+{1, 3015022068},
-+{1, 1935326986},
-+{5, 1648098256},
-+{2, 3545360164},
-+{1, 4106897609},
-+{1, 1528415857},
-+{1, 2707734286},
-+{2, 3149837061},
-+{2, 4263280906},
-+
- };
- 
- // NOTE: These tests rely on CreateNewBlock doing its own self-validation!
diff --git a/src/alert.cpp b/src/alert.cpp
index 44f4d5eec6..e00847aadb 100644
--- a/src/alert.cpp
+++ b/src/alert.cpp
@@ -19,9 +19,6 @@ using namespace std;
 map<uint256, CAlert> mapAlerts;
 CCriticalSection cs_mapAlerts;
 
-static const char* pszMainKey = "04fc9702847840aaf195de8442ebecedf5b095cdbb9bc716bda9110971b28a49e0ead8564ff0db22209e0374782c093bb899692d524e9d6a6956e7c5ecbcd68284";
-static const char* pszTestKey = "04302390343f91cc401d56d68b123028bf52e5fca1939df127f63c6467cdf9c8e2c14b61104cf817d0b780da337893ecc4aaff1309e536162dabbdb45200ca2b0a";
-
 void CUnsignedAlert::SetNull()
 {
     nVersion = 1;
@@ -144,7 +141,7 @@ bool CAlert::RelayTo(CNode* pnode) const
 
 bool CAlert::CheckSignature() const
 {
-    CPubKey key(ParseHex(fTestNet ? pszTestKey : pszMainKey));
+    CPubKey key(Params().AlertKey());
     if (!key.Verify(Hash(vchMsg.begin(), vchMsg.end()), vchSig))
         return error("CAlert::CheckSignature() : verify signature failed");
 
diff --git a/src/base58.h b/src/base58.h
index efe3a95ebd..630d6fe9aa 100644
--- a/src/base58.h
+++ b/src/base58.h
@@ -18,6 +18,7 @@
 #include <string>
 #include <vector>
 
+#include "chainparams.h"
 #include "bignum.h"
 #include "key.h"
 #include "script.h"
@@ -270,21 +271,13 @@ public:
 class CBitcoinAddress : public CBase58Data
 {
 public:
-    enum
-    {
-        PUBKEY_ADDRESS = 0,
-        SCRIPT_ADDRESS = 5,
-        PUBKEY_ADDRESS_TEST = 111,
-        SCRIPT_ADDRESS_TEST = 196,
-    };
-
     bool Set(const CKeyID &id) {
-        SetData(fTestNet ? PUBKEY_ADDRESS_TEST : PUBKEY_ADDRESS, &id, 20);
+        SetData(Params().Base58Prefix(CChainParams::PUBKEY_ADDRESS), &id, 20);
         return true;
     }
 
     bool Set(const CScriptID &id) {
-        SetData(fTestNet ? SCRIPT_ADDRESS_TEST : SCRIPT_ADDRESS, &id, 20);
+        SetData(Params().Base58Prefix(CChainParams::SCRIPT_ADDRESS), &id, 20);
         return true;
     }
 
@@ -295,32 +288,10 @@ public:
 
     bool IsValid() const
     {
-        unsigned int nExpectedSize = 20;
-        bool fExpectTestNet = false;
-        switch(nVersion)
-        {
-            case PUBKEY_ADDRESS:
-                nExpectedSize = 20; // Hash of public key
-                fExpectTestNet = false;
-                break;
-            case SCRIPT_ADDRESS:
-                nExpectedSize = 20; // Hash of CScript
-                fExpectTestNet = false;
-                break;
-
-            case PUBKEY_ADDRESS_TEST:
-                nExpectedSize = 20;
-                fExpectTestNet = true;
-                break;
-            case SCRIPT_ADDRESS_TEST:
-                nExpectedSize = 20;
-                fExpectTestNet = true;
-                break;
-
-            default:
-                return false;
-        }
-        return fExpectTestNet == fTestNet && vchData.size() == nExpectedSize;
+        bool fCorrectSize = vchData.size() == 20;
+        bool fKnownVersion = nVersion == Params().Base58Prefix(CChainParams::PUBKEY_ADDRESS) ||
+                             nVersion == Params().Base58Prefix(CChainParams::SCRIPT_ADDRESS);
+        return fCorrectSize && fKnownVersion;
     }
 
     CBitcoinAddress()
@@ -345,48 +316,27 @@ public:
     CTxDestination Get() const {
         if (!IsValid())
             return CNoDestination();
-        switch (nVersion) {
-        case PUBKEY_ADDRESS:
-        case PUBKEY_ADDRESS_TEST: {
-            uint160 id;
-            memcpy(&id, &vchData[0], 20);
+        uint160 id;
+        memcpy(&id, &vchData[0], 20);
+        if (nVersion == Params().Base58Prefix(CChainParams::PUBKEY_ADDRESS))
             return CKeyID(id);
-        }
-        case SCRIPT_ADDRESS:
-        case SCRIPT_ADDRESS_TEST: {
-            uint160 id;
-            memcpy(&id, &vchData[0], 20);
+        else if (nVersion == Params().Base58Prefix(CChainParams::SCRIPT_ADDRESS))
             return CScriptID(id);
-        }
-        }
-        return CNoDestination();
+        else
+            return CNoDestination();
     }
 
     bool GetKeyID(CKeyID &keyID) const {
-        if (!IsValid())
+        if (!IsValid() || nVersion != Params().Base58Prefix(CChainParams::PUBKEY_ADDRESS))
             return false;
-        switch (nVersion) {
-        case PUBKEY_ADDRESS:
-        case PUBKEY_ADDRESS_TEST: {
-            uint160 id;
-            memcpy(&id, &vchData[0], 20);
-            keyID = CKeyID(id);
-            return true;
-        }
-        default: return false;
-        }
+        uint160 id;
+        memcpy(&id, &vchData[0], 20);
+        keyID = CKeyID(id);
+        return true;
     }
 
     bool IsScript() const {
-        if (!IsValid())
-            return false;
-        switch (nVersion) {
-        case SCRIPT_ADDRESS:
-        case SCRIPT_ADDRESS_TEST: {
-            return true;
-        }
-        default: return false;
-        }
+        return IsValid() && nVersion == Params().Base58Prefix(CChainParams::SCRIPT_ADDRESS);
     }
 };
 
@@ -401,7 +351,7 @@ public:
     void SetKey(const CKey& vchSecret)
     {
         assert(vchSecret.IsValid());
-        SetData(fTestNet ? 239 : 128, vchSecret.begin(), vchSecret.size());
+        SetData(Params().Base58Prefix(CChainParams::SECRET_KEY), vchSecret.begin(), vchSecret.size());
         if (vchSecret.IsCompressed())
             vchData.push_back(1);
     }
@@ -415,20 +365,9 @@ public:
 
     bool IsValid() const
     {
-        bool fExpectTestNet = false;
-        switch(nVersion)
-        {
-            case 128:
-                break;
-
-            case 239:
-                fExpectTestNet = true;
-                break;
-
-            default:
-                return false;
-        }
-        return fExpectTestNet == fTestNet && (vchData.size() == 32 || (vchData.size() == 33 && vchData[32] == 1));
+        bool fExpectedFormat = vchData.size() == 32 || (vchData.size() == 33 && vchData[32] == 1);
+        bool fCorrectVersion = nVersion == Params().Base58Prefix(CChainParams::SECRET_KEY);
+        return fExpectedFormat && fCorrectVersion;
     }
 
     bool SetString(const char* pszSecret)
diff --git a/src/bitcoind.cpp b/src/bitcoind.cpp
index 682a214fb2..bc23cf5507 100644
--- a/src/bitcoind.cpp
+++ b/src/bitcoind.cpp
@@ -67,6 +67,10 @@ bool AppInit(int argc, char* argv[])
 
         if (fCommandLine)
         {
+            if (!SelectParamsFromCommandLine()) {
+                fprintf(stderr, "Error: invalid combination of -regtest and -testnet.\n");
+                return false;
+            }
             int ret = CommandLineRPC(argc, argv);
             exit(ret);
         }
diff --git a/src/bitcoinrpc.cpp b/src/bitcoinrpc.cpp
index 285a88c8d8..febb475db3 100644
--- a/src/bitcoinrpc.cpp
+++ b/src/bitcoinrpc.cpp
@@ -3,6 +3,7 @@
 // Distributed under the MIT/X11 software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include "chainparams.h"
 #include "init.h"
 #include "util.h"
 #include "sync.h"
@@ -38,11 +39,6 @@ static map<string, boost::shared_ptr<deadline_timer> > deadlineTimers;
 static ssl::context* rpc_ssl_context = NULL;
 static boost::thread_group* rpc_worker_group = NULL;
 
-static inline unsigned short GetDefaultRPCPort()
-{
-    return GetBoolArg("-testnet", false) ? 18332 : 8332;
-}
-
 Object JSONRPCError(int code, const string& message)
 {
     Object error;
@@ -724,8 +720,8 @@ static void RPCAcceptHandler(boost::shared_ptr< basic_socket_acceptor<Protocol,
 void StartRPCThreads()
 {
     strRPCUserColonPass = mapArgs["-rpcuser"] + ":" + mapArgs["-rpcpassword"];
-    if ((mapArgs["-rpcpassword"] == "") ||
-        (mapArgs["-rpcuser"] == mapArgs["-rpcpassword"]))
+    if (((mapArgs["-rpcpassword"] == "") ||
+         (mapArgs["-rpcuser"] == mapArgs["-rpcpassword"])) && Params().RequireRPCPassword())
     {
         unsigned char rand_pwd[32];
         RAND_bytes(rand_pwd, 32);
@@ -780,7 +776,7 @@ void StartRPCThreads()
     // Try a dual IPv6/IPv4 socket, falling back to separate IPv4 and IPv6 sockets
     const bool loopback = !mapArgs.count("-rpcallowip");
     asio::ip::address bindAddress = loopback ? asio::ip::address_v6::loopback() : asio::ip::address_v6::any();
-    ip::tcp::endpoint endpoint(bindAddress, GetArg("-rpcport", GetDefaultRPCPort()));
+    ip::tcp::endpoint endpoint(bindAddress, GetArg("-rpcport", Params().RPCPort()));
     boost::system::error_code v6_only_error;
     boost::shared_ptr<ip::tcp::acceptor> acceptor(new ip::tcp::acceptor(*rpc_io_service));
 
@@ -1078,7 +1074,7 @@ Object CallRPC(const string& strMethod, const Array& params)
     asio::ssl::stream<asio::ip::tcp::socket> sslStream(io_service, context);
     SSLIOStreamDevice<asio::ip::tcp> d(sslStream, fUseSSL);
     iostreams::stream< SSLIOStreamDevice<asio::ip::tcp> > stream(d);
-    if (!d.connect(GetArg("-rpcconnect", "127.0.0.1"), GetArg("-rpcport", itostr(GetDefaultRPCPort()))))
+    if (!d.connect(GetArg("-rpcconnect", "127.0.0.1"), GetArg("-rpcport", itostr(Params().RPCPort()))))
         throw runtime_error("couldn't connect to server");
 
     // HTTP basic authentication
diff --git a/src/chainparams.cpp b/src/chainparams.cpp
new file mode 100644
index 0000000000..8859424d20
--- /dev/null
+++ b/src/chainparams.cpp
@@ -0,0 +1,286 @@
+// Copyright (c) 2010 Satoshi Nakamoto
+// Copyright (c) 2009-2012 The Bitcoin developers
+// Distributed under the MIT/X11 software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "assert.h"
+
+#include "chainparams.h"
+#include "main.h"
+#include "util.h"
+
+//
+// Main network
+//
+
+unsigned int pnSeed[] =
+{
+    0xe473042e, 0xb177f2ad, 0xd63f3fb2, 0xf864f736, 0x44a23ac7, 0xcf6d9650, 0xd648042e, 0x0536f447,
+    0x3c654ed0, 0x3e16a5bc, 0xa38e09b0, 0xdfae795b, 0xabfeca5b, 0x94ad7840, 0xf3b9f1c7, 0xbe70e0ad,
+    0x3bbd09b0, 0x8d0c7dd5, 0x3b2a7332, 0x1a06175e, 0x581f175e, 0xca0d2dcc, 0x0fdbc658, 0xcf591ec7,
+    0x295a12b2, 0xb4707bce, 0x68bb09b0, 0x4e735747, 0x89709553, 0x05a7814e, 0x5b8ec658, 0x402c5512,
+    0xe80d0905, 0x17681a5e, 0xc02aa748, 0x9f811741, 0x5f321cb0, 0x23e1ee47, 0xaf7f170c, 0xaa240ab0,
+    0xedea6257, 0x76106bc1, 0x2cf310cc, 0x08612acb, 0x9c682e4e, 0x8e963c6c, 0x443c795b, 0x22e246b8,
+    0xfa1f2dcc, 0x90118140, 0x3821042e, 0x33c3fd2e, 0x10046d5b, 0x40d14b3e, 0x7fb8f8ce, 0x67696550,
+    0xeeecbe58, 0x4f341745, 0x46b8fbd5, 0xc8463932, 0x6b73e862, 0x4c715932, 0x4a6785d5, 0xce3a64c2,
+    0xde9604c7, 0x9b06884f, 0x18002a45, 0xea9bc345, 0xc4f1c658, 0xe475c1c7, 0xdd3e795b, 0x9722175e,
+    0x34562f4e, 0x66c46e4e, 0x40bb1243, 0x7d9171d0, 0x17b8dbd5, 0x63cbfd2e, 0x1a08b8d8, 0x6175a73b,
+    0x228d2660, 0x8627c658, 0x9c566644, 0x38cca5bc, 0x3089de5b, 0x92e25f5d, 0xa393f73f, 0xcc92dc3e,
+    0x27487446, 0x62cbfd2e, 0x9d983b45, 0xf72a09b0, 0xf75f042e, 0x6434bb6a, 0xb29e77d8, 0x19be4fd9,
+    0x76443243, 0x9dd72645, 0x694cef43, 0x89c2efd5, 0x5f1c5058, 0x46c6e45b, 0xe1391b40, 0x77ccefd5,
+    0x472e5a6d, 0x85709553, 0xdd4f5d4c, 0x64ef5a46, 0x7f0ae502, 0xcf08d850, 0x3460042e, 0xeafa2d42,
+    0x793c9044, 0x9d094746, 0x1ab9b153, 0xbfe9a5bc, 0x34771fb0, 0xb7722e32, 0x1168964b, 0x19b06ab8,
+    0x19243b25, 0x13188045, 0xb4070905, 0x728ebb5d, 0x44f24ac8, 0xa317fead, 0x642f6a57, 0x3d951f32,
+    0x3d312e4e, 0xfac4d048, 0xefc4dd50, 0x52b9f1c7, 0xc14d3cc3, 0x0219ea44, 0x3b79d058, 0xfa217242,
+    0x39c80647, 0xfb697252, 0x1d495a42, 0x0aa81f4e, 0x58249ab8, 0xe6a8e6c3, 0x2bc4dad8, 0x85963c6c,
+    0xa4ce09b0, 0x2005f536, 0x5cc2703e, 0x1992de43, 0x74e86b4c, 0xe7085653, 0xf5e15a51, 0xb4872b60,
+    0x29e2b162, 0xa07ea053, 0x8229fd18, 0x4562ec4d, 0x8dec814e, 0x36cfa4cf, 0x96461032, 0x3c8770de,
+    0xd10a1f5f, 0x95934641, 0x97cd65d0, 0x2e35324a, 0x2566ba1f, 0x1ca1a9d1, 0xb808b8d5, 0xf9a24a5d,
+    0xafc8d431, 0xe4b8d9b2, 0x0f5321b2, 0x330bc658, 0x74b347ce, 0x972babd5, 0x044f7d4f, 0x06562f4e,
+    0x8b8d3c6c, 0x3507c658, 0xe4174e4d, 0xf1c009b0, 0x52249ab8, 0x27211772, 0xf6a9ba59, 0x7a391b40,
+    0x855dc6c0, 0x291f20b2, 0xe29bc345, 0x90963c6c, 0x0af70732, 0x4242a91f, 0x4c531d48, 0xa32df948,
+    0x627e3044, 0x65be1f54, 0x1a0cbf83, 0x6a443532, 0x8d5f1955, 0xbafa8132, 0x3534bdd5, 0xca019dd9,
+    0x8a0d9332, 0x5584e7d8, 0x7cd1f25e, 0xeabe3fb2, 0x2945d0d1, 0x46415718, 0x70d6042e, 0x99eb76d0,
+    0x9ece09b0, 0xb3777418, 0x5e5e91d9, 0x237a3ab0, 0xf512b62e, 0x45dec347, 0x59b7f862, 0x4c443b25,
+    0x3cc6484b, 0x9a8ec6d1, 0x021eea44, 0xc9483944, 0xfd567e32, 0xfd204bb2, 0xc5330bcc, 0x5202894e,
+    0xf9e309b0, 0x4cc17557, 0xdb9064ae, 0xe19e77d8, 0x25857f60, 0xeb4a15ad, 0x1f47f554, 0xea4472d9,
+    0xd20de593, 0xf5733b25, 0x11892b54, 0x5729d35f, 0xe6188cd1, 0x488b132e, 0x541c534a, 0xa8e854ae,
+    0xa255a66c, 0x33688763, 0xc6629ac6, 0xc20a6265, 0xcd92a059, 0x72029d3b, 0x4c298f5e, 0x51452e4e,
+    0xbb065058, 0x15fd2dcc, 0xf40c135e, 0x615a0bad, 0x0c6a6805, 0x4971a7ad, 0x17f2a5d5, 0xf8babf47,
+    0xb61f50ad, 0x4e1451b1, 0xf72d9252, 0x5c2abe58, 0xbd987c61, 0x084ae5cf, 0x20781fb0, 0x38b0f160,
+    0x18aac705, 0x14f86dc1, 0x5556f481, 0x0a36c144, 0xeb446e4c, 0x2c1c0d6c, 0xbd0ff860, 0x869f92db,
+    0x36c94f4c, 0x05502444, 0x148fe55b, 0xd5301e59, 0xd57a8f45, 0x110dc04a, 0x8670fc36, 0xee733b25,
+    0xca56f481, 0x2a5c3bae, 0x844b0905, 0x1e51fe53, 0x0241c244, 0x59c0614e, 0x94e70a55, 0x7312fead,
+    0xb735be44, 0xa55d0905, 0x2f63962e, 0x14a4e15b, 0x63f8f05c, 0x62d0d262, 0x3cab41ad, 0x87f1b1cb,
+    0x018da6b8, 0xb3967dd5, 0xcb56f481, 0x685ad718, 0x3b4aeeca, 0x8d106bc1, 0x51180905, 0x72660f48,
+    0x1521a243, 0x5b56f481, 0x6390e560, 0xdd61464e, 0x58353b25, 0x553fc062, 0x27c45d59, 0xacc62e4e,
+    0x0d5a1cd9, 0x7f65f442, 0xbdeef660, 0xf1bd1855, 0xf8473cae, 0x13b120b2, 0x442440d0, 0x53fd4352,
+    0xa305fc57, 0x458be84d, 0x639ce1c3, 0xebaaee47, 0x95e2c247, 0xf056f481, 0x6256f481, 0x1d87c65e,
+    0x0a453418, 0x5beb175e, 0xd64f1618, 0xc360795b, 0x2fbf5753, 0xa8c58e53, 0x651cec52, 0x9d37b043,
+    0x124a9758, 0x5242e4a9, 0x89913c6c, 0x880efe2e, 0x2f2f2f0c, 0x72b26751, 0x2896e46d, 0x80f4166c,
+    0x320d59ad, 0xc50151d0, 0x11a8aa43, 0xccf56057, 0x5fbad118, 0x4719b151, 0x2b5f4bc0, 0x4d7a4a50,
+    0xad06e047, 0x62ef5a46, 0x5aebde58, 0xdf7aa66c, 0x851acb50, 0x66b9a559, 0x3e9bb153, 0xcc512f2e,
+    0xc073b08e, 0xd519be58, 0xe981ea4d, 0x12fd50cb, 0x378739ad, 0x06683cae, 0xa22310b2, 0xc185c705,
+    0x8741b545, 0xa26c8318, 0x22d5bc43, 0x39201ec0, 0x68581e3e, 0xdc9bcf62, 0xd508cc82, 0xb149675b,
+    0x4c9609b0, 0x84feb84c, 0x08291e2e, 0xfd2253b2, 0x1fd269c1, 0xc9483932, 0x4d641fb0, 0x7d37c918,
+    0xa9de20ad, 0x77e2d655, 0x6d421b59, 0xd7668f80, 0xced09b62, 0xa9e5a5bc, 0xa4074e18, 0x60fc5ecc,
+    0x01300148, 0x68062444, 0xb4224847, 0xed3aa443, 0xb772fb43, 0x9f56f481, 0x220dfd18, 0x8e1c3d6c,
+    0xc44f09b0, 0x7df2bb73, 0xe22fb844, 0xea534242, 0xb6a755d4, 0xa036654b, 0x138ece5b, 0xda65d3c3,
+    0x955871bc, 0x792124b0, 0xfc82594c, 0x851d494b, 0x2c7aee47, 0x26af46b8, 0x1416252e, 0xa8abb944,
+    0x36c49d25, 0x674f645d, 0x363646b8, 0x9e1a2942, 0x66d0c154, 0xc6c2a545, 0x3570f2ad, 0xe7d547c7,
+    0x7d104932, 0x18cb9c18, 0x1dcfa4cf, 0xd156f481, 0x2a02b91f, 0x3eeb3fa8, 0xcac4175e, 0x34146d42,
+    0x994c4d46, 0x5666f440, 0x85d6713e, 0x5ecb296c, 0x0ea0ae46, 0x87e69f42, 0xc58409b0, 0x1f3436ae,
+    0x21dc6a57, 0x4ad1cd42, 0xfb8c1a4c, 0x52d3dab2, 0x3769894b, 0xb52f1c62, 0x3677916d, 0x82b3fe57,
+    0x493d4ac6, 0x9f963c6c, 0x5d91ff60, 0x458e0dad, 0xa49d0947, 0x491a3e18, 0x4aadcd5b, 0x0e46494b,
+    0x1d1610ad, 0x1a10af5d, 0x4956f481, 0x207a3eae, 0x77e73244, 0xfa3b8742, 0x3261fc36, 0xfcebf536,
+    0x1662e836, 0xf655f636, 0xa2dbd0ad, 0x23036693, 0x30448432, 0xa2b03463, 0x30730344, 0x8e4a6882,
+    0x0c50a1cb, 0xc8d8c06b, 0xc9cd6191, 0xf443db50, 0xa9553c50, 0x23145847, 0xc35da66c, 0x29c12a60,
+    0x55c2b447, 0x7434f75c, 0x61660640, 0xde2a7018, 0xc639494c, 0x1c306fce, 0x19b89244, 0xd29a6462,
+    0x462cd1b2, 0x29902f44, 0x2817fa53, 0x21a30905, 0x7777ae46, 0x288443a1, 0x7bee5148, 0xc2a8b043,
+    0xf5c3d35f, 0x2311ef84, 0x57de08a4, 0x6b221bb2, 0xf2625846, 0x4b9e09b0, 0xa24f880e, 0x22b11447,
+    0xb3a0c744, 0x919e77d8, 0xec8b64ae, 0xff5c8d45, 0x7b15b484, 0x32679a5f, 0xba80b62e, 0x05c25c61,
+    0x60014746, 0x5e8fb04c, 0xe67c0905, 0x4329c658, 0xac8fe555, 0xf875e647, 0x67406386, 0x35ceea18,
+    0xbb79484b, 0xd7b9fa62, 0x238209b0, 0x208a1d32, 0x9630995e, 0x039c1318, 0x6e48006c, 0x60582344,
+    0xadbb0150, 0x853fd462, 0x03772e4e, 0x652ce960, 0x49b630ad, 0x9993af43, 0x3735b34b, 0x548a07d9,
+    0x55a44aad, 0xa23d1bcc, 0xfdbb2f4e, 0x530b24a0, 0x0a44b451, 0x6827c657, 0x1f66494b, 0x4e680a47,
+    0x77e7b747, 0xa5eb3fa8, 0x6649764a, 0xd4e76c4b, 0x2c691fb0, 0xf1292e44, 0xc6d6c774, 0x85d23775,
+    0x28275f4d, 0x259ae46d, 0x02424e81, 0x5f16be58, 0xe707c658, 0x49eae5c7, 0xd5d147ad, 0x9a7abdc3,
+    0xe8ac7fc7, 0x84ec3aae, 0xc24942d0, 0x294aa318, 0x08ac3d18, 0x8894042e, 0xb24609b0, 0x9bcaab58,
+    0xc400f712, 0xd5c512b8, 0x2c02cc62, 0x25080fd8, 0xed74a847, 0x18a5ec5e, 0x9850ec6d, 0xf8909758,
+    0x7f56f481, 0x4496f23c, 0xae27784f, 0xcb7cd93e, 0x06e32860, 0x50b9a84f, 0x3660434a, 0x09161f5f,
+    0x900486bc, 0x08055459, 0xe7ec1017, 0x7e39494c, 0x4f443b25, 0x14751a8a, 0x717d03d4, 0xbd0e24d8,
+    0x054b6f56, 0x854c496c, 0xd92a454a, 0xc39bd054, 0x6093614b, 0x9dbad754, 0x5bf0604a, 0x99f22305
+};
+
+class CMainParams : public CChainParams {
+public:
+    CMainParams() {
+        // 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.
+        pchMessageStart[0] = 0xf9;
+        pchMessageStart[1] = 0xbe;
+        pchMessageStart[2] = 0xb4;
+        pchMessageStart[3] = 0xd9;
+        vAlertPubKey = ParseHex("04fc9702847840aaf195de8442ebecedf5b095cdbb9bc716bda9110971b28a49e0ead8564ff0db22209e0374782c093bb899692d524e9d6a6956e7c5ecbcd68284");
+        nDefaultPort = 8333;
+        nRPCPort = 8332;
+        bnProofOfWorkLimit = CBigNum(~uint256(0) >> 32);
+        nSubsidyHalvingInterval = 210000;
+
+        // Build the genesis block. Note that the output of the genesis coinbase cannot
+        // be spent as it did not originally exist in the database.
+        //
+        // CBlock(hash=000000000019d6, ver=1, hashPrevBlock=00000000000000, hashMerkleRoot=4a5e1e, nTime=1231006505, nBits=1d00ffff, nNonce=2083236893, vtx=1)
+        //   CTransaction(hash=4a5e1e, ver=1, vin.size=1, vout.size=1, nLockTime=0)
+        //     CTxIn(COutPoint(000000, -1), coinbase 04ffff001d0104455468652054696d65732030332f4a616e2f32303039204368616e63656c6c6f72206f6e206272696e6b206f66207365636f6e64206261696c6f757420666f722062616e6b73)
+        //     CTxOut(nValue=50.00000000, scriptPubKey=0x5F1DF16B2B704C8A578D0B)
+        //   vMerkleTree: 4a5e1e
+        const char* pszTimestamp = "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks";
+        CTransaction txNew;
+        txNew.vin.resize(1);
+        txNew.vout.resize(1);
+        txNew.vin[0].scriptSig = CScript() << 486604799 << CBigNum(4) << vector<unsigned char>((const unsigned char*)pszTimestamp, (const unsigned char*)pszTimestamp + strlen(pszTimestamp));
+        txNew.vout[0].nValue = 50 * COIN;
+        txNew.vout[0].scriptPubKey = CScript() << ParseHex("04678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef38c4f35504e51ec112de5c384df7ba0b8d578a4c702b6bf11d5f") << OP_CHECKSIG;
+        genesis.vtx.push_back(txNew);
+        genesis.hashPrevBlock = 0;
+        genesis.hashMerkleRoot = genesis.BuildMerkleTree();
+        genesis.nVersion = 1;
+        genesis.nTime    = 1231006505;
+        genesis.nBits    = 0x1d00ffff;
+        genesis.nNonce   = 2083236893;
+
+        hashGenesisBlock = genesis.GetHash();
+        assert(hashGenesisBlock == uint256("0x000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f"));
+        assert(genesis.hashMerkleRoot == uint256("0x4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b"));
+
+        vSeeds.push_back(CDNSSeedData("bitcoin.sipa.be", "seed.bitcoin.sipa.be"));
+        vSeeds.push_back(CDNSSeedData("bluematt.me", "dnsseed.bluematt.me"));
+        vSeeds.push_back(CDNSSeedData("dashjr.org", "dnsseed.bitcoin.dashjr.org"));
+        vSeeds.push_back(CDNSSeedData("xf2.org", "bitseed.xf2.org"));
+
+        base58Prefixes[PUBKEY_ADDRESS] = 0;
+        base58Prefixes[SCRIPT_ADDRESS] = 5;
+        base58Prefixes[SECRET_KEY] = 128;
+
+        // Convert the pnSeeds array into usable address objects.
+        for (unsigned int i = 0; i < ARRAYLEN(pnSeed); i++)
+        {
+            // It'll only connect to one or two seed nodes because once it connects,
+            // it'll get a pile of addresses with newer timestamps.
+            // Seed nodes are given a random 'last seen time' of between one and two
+            // weeks ago.
+            const int64 nOneWeek = 7*24*60*60;
+            struct in_addr ip;
+            memcpy(&ip, &pnSeed[i], sizeof(ip));
+            CAddress addr(CService(ip, GetDefaultPort()));
+            addr.nTime = GetTime() - GetRand(nOneWeek) - nOneWeek;
+            vFixedSeeds.push_back(addr);
+        }
+    }
+
+    virtual const CBlock& GenesisBlock() const { return genesis; }
+    virtual Network NetworkID() const { return CChainParams::MAIN; }
+
+    virtual const vector<CAddress>& FixedSeeds() const {
+        return vFixedSeeds;
+    }
+protected:
+    CBlock genesis;
+    vector<CAddress> vFixedSeeds;
+};
+static CMainParams mainParams;
+
+
+//
+// Testnet (v3)
+//
+class CTestNetParams : public CMainParams {
+public:
+    CTestNetParams() {
+        // 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.
+        pchMessageStart[0] = 0x0b;
+        pchMessageStart[1] = 0x11;
+        pchMessageStart[2] = 0x09;
+        pchMessageStart[3] = 0x07;
+        vAlertPubKey = ParseHex("04302390343f91cc401d56d68b123028bf52e5fca1939df127f63c6467cdf9c8e2c14b61104cf817d0b780da337893ecc4aaff1309e536162dabbdb45200ca2b0a");
+        nDefaultPort = 18333;
+        nRPCPort = 18332;
+        strDataDir = "testnet3";
+
+        // Modify the testnet genesis block so the timestamp is valid for a later start.
+        genesis.nTime = 1296688602;
+        genesis.nNonce = 414098458;
+        hashGenesisBlock = genesis.GetHash();
+        assert(hashGenesisBlock == uint256("000000000933ea01ad0ee984209779baaec3ced90fa3f408719526f8d77f4943"));
+
+        vFixedSeeds.clear();
+        vSeeds.clear();
+        vSeeds.push_back(CDNSSeedData("bitcoin.petertodd.org", "testnet-seed.bitcoin.petertodd.org"));
+        vSeeds.push_back(CDNSSeedData("bluematt.me", "testnet-seed.bluematt.me"));
+
+        base58Prefixes[PUBKEY_ADDRESS] = 111;
+        base58Prefixes[SCRIPT_ADDRESS] = 196;
+        base58Prefixes[SECRET_KEY] = 239;
+
+    }
+    virtual Network NetworkID() const { return CChainParams::TESTNET; }
+};
+static CTestNetParams testNetParams;
+
+
+//
+// Regression test
+//
+class CRegTestParams : public CTestNetParams {
+public:
+    CRegTestParams() {
+        pchMessageStart[0] = 0xfa;
+        pchMessageStart[1] = 0xbf;
+        pchMessageStart[2] = 0xb5;
+        pchMessageStart[3] = 0xda;
+        nSubsidyHalvingInterval = 150;
+        bnProofOfWorkLimit = CBigNum(~uint256(0) >> 1);
+        genesis.nTime = 1296688602;
+        genesis.nBits = 0x207fffff;
+        genesis.nNonce = 2;
+        hashGenesisBlock = genesis.GetHash();
+        nDefaultPort = 18444;
+        strDataDir = "regtest";
+        assert(hashGenesisBlock == uint256("0x0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206"));
+
+        vSeeds.clear();  // Regtest mode doesn't have any DNS seeds.
+
+        base58Prefixes[PUBKEY_ADDRESS] = 0;
+        base58Prefixes[SCRIPT_ADDRESS] = 5;
+        base58Prefixes[SECRET_KEY] = 128;
+    }
+
+    virtual bool RequireRPCPassword() const { return false; }
+    virtual Network NetworkID() const { return CChainParams::REGTEST; }
+};
+static CRegTestParams regTestParams;
+
+static CChainParams *pCurrentParams = &mainParams;
+
+const CChainParams &Params() {
+    return *pCurrentParams;
+}
+
+void SelectParams(CChainParams::Network network) {
+    switch (network) {
+        case CChainParams::MAIN:
+            pCurrentParams = &mainParams;
+            break;
+        case CChainParams::TESTNET:
+            pCurrentParams = &testNetParams;
+            break;
+        case CChainParams::REGTEST:
+            pCurrentParams = &regTestParams;
+            break;
+        default:
+            assert(false && "Unimplemented network");
+            return;
+    }
+}
+
+bool SelectParamsFromCommandLine() {
+    bool fRegTest = GetBoolArg("-regtest", false);
+    bool fTestNet = GetBoolArg("-testnet", false);
+
+    if (fTestNet && fRegTest) {
+        return false;
+    }
+
+    if (fRegTest) {
+        SelectParams(CChainParams::REGTEST);
+    } else if (fTestNet) {
+        SelectParams(CChainParams::TESTNET);
+    } else {
+        SelectParams(CChainParams::MAIN);
+    }
+    return true;
+}
diff --git a/src/chainparams.h b/src/chainparams.h
new file mode 100644
index 0000000000..572712b589
--- /dev/null
+++ b/src/chainparams.h
@@ -0,0 +1,102 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2013 The Bitcoin developers
+// Distributed under the MIT/X11 software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_CHAIN_PARAMS_H
+#define BITCOIN_CHAIN_PARAMS_H
+
+#include "bignum.h"
+#include "uint256.h"
+#include "util.h"
+
+#include <vector>
+
+using namespace std;
+
+#define MESSAGE_START_SIZE 4
+typedef unsigned char MessageStartChars[MESSAGE_START_SIZE];
+
+class CAddress;
+class CBlock;
+
+struct CDNSSeedData {
+    string name, host;
+    CDNSSeedData(const string &strName, const string &strHost) : name(strName), host(strHost) {}
+};
+
+/**
+ * CChainParams defines various tweakable parameters of a given instance of the
+ * Bitcoin system. There are three: the main network on which people trade goods
+ * and services, the public test network which gets reset from time to time and
+ * a regression test mode which is intended for private networks only. It has
+ * minimal difficulty to ensure that blocks can be found instantly.
+ */
+class CChainParams
+{
+public:
+    enum Network {
+        MAIN,
+        TESTNET,
+        REGTEST,
+    };
+
+    enum Base58Type {
+        PUBKEY_ADDRESS,
+        SCRIPT_ADDRESS,
+        SECRET_KEY,
+
+        MAX_BASE58_TYPES
+    };
+
+    const uint256& HashGenesisBlock() const { return hashGenesisBlock; }
+    const MessageStartChars& MessageStart() const { return pchMessageStart; }
+    const vector<unsigned char>& AlertKey() const { return vAlertPubKey; }
+    int GetDefaultPort() const { return nDefaultPort; }
+    const CBigNum& ProofOfWorkLimit() const { return bnProofOfWorkLimit; }
+    int SubsidyHalvingInterval() const { return nSubsidyHalvingInterval; }
+    virtual const CBlock& GenesisBlock() const = 0;
+    virtual bool RequireRPCPassword() const { return true; }
+    const string& DataDir() const { return strDataDir; }
+    virtual Network NetworkID() const = 0;
+    const vector<CDNSSeedData>& DNSSeeds() const { return vSeeds; }
+    int Base58Prefix(Base58Type type) const { return base58Prefixes[type]; }
+    virtual const vector<CAddress>& FixedSeeds() const = 0;
+    int RPCPort() const { return nRPCPort; }
+protected:
+    CChainParams() {};
+
+    uint256 hashGenesisBlock;
+    MessageStartChars pchMessageStart;
+    // Raw pub key bytes for the broadcast alert signing key.
+    vector<unsigned char> vAlertPubKey;
+    int nDefaultPort;
+    int nRPCPort;
+    CBigNum bnProofOfWorkLimit;
+    int nSubsidyHalvingInterval;
+    string strDataDir;
+    vector<CDNSSeedData> vSeeds;
+    int base58Prefixes[MAX_BASE58_TYPES];
+};
+
+/**
+ * Return the currently selected parameters. This won't change after app startup
+ * outside of the unit tests.
+ */
+const CChainParams &Params();
+
+/** Sets the params returned by Params() to those for the given network. */
+void SelectParams(CChainParams::Network network);
+
+/**
+ * Looks for -regtest or -testnet and then calls SelectParams as appropriate.
+ * Returns false if an invalid combination is given.
+ */
+bool SelectParamsFromCommandLine();
+
+inline bool TestNet() {
+    // Note: it's deliberate that this returns "false" for regression test mode.
+    return Params().NetworkID() == CChainParams::TESTNET;
+}
+
+#endif
diff --git a/src/checkpoints.cpp b/src/checkpoints.cpp
index 7643ec5df8..ba29e2463e 100644
--- a/src/checkpoints.cpp
+++ b/src/checkpoints.cpp
@@ -56,7 +56,7 @@ namespace Checkpoints
         60000.0     // * estimated number of transactions per day after checkpoint
     };
 
-    static MapCheckpoints mapCheckpointsTestnet = 
+    static MapCheckpoints mapCheckpointsTestnet =
         boost::assign::map_list_of
         ( 546, uint256("000000002a936ca763904c3c35fce2f3556c559c0214345d31b1bcebf76acb70"))
         ;
@@ -68,7 +68,7 @@ namespace Checkpoints
     };
 
     const CCheckpointData &Checkpoints() {
-        if (fTestNet)
+        if (TestNet())
             return dataTestnet;
         else
             return data;
diff --git a/src/db.cpp b/src/db.cpp
index 1f53917602..93f3f5d8c4 100644
--- a/src/db.cpp
+++ b/src/db.cpp
@@ -3,6 +3,7 @@
 // Distributed under the MIT/X11 software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include "chainparams.h"
 #include "db.h"
 #include "util.h"
 #include "hash.h"
@@ -488,8 +489,6 @@ void CDBEnv::Flush(bool fShutdown)
 // CAddrDB
 //
 
-unsigned char CAddrDB::pchMessageStart[4] = { 0x00, 0x00, 0x00, 0x00 };
-
 CAddrDB::CAddrDB()
 {
     pathAddr = GetDataDir() / "peers.dat";
@@ -504,7 +503,7 @@ bool CAddrDB::Write(const CAddrMan& addr)
 
     // serialize addresses, checksum data up to that point, then append csum
     CDataStream ssPeers(SER_DISK, CLIENT_VERSION);
-    ssPeers << FLATDATA(CAddrDB::pchMessageStart);
+    ssPeers << FLATDATA(Params().MessageStart());
     ssPeers << addr;
     uint256 hash = Hash(ssPeers.begin(), ssPeers.end());
     ssPeers << hash;
@@ -569,11 +568,11 @@ bool CAddrDB::Read(CAddrMan& addr)
 
     unsigned char pchMsgTmp[4];
     try {
-        // de-serialize file header (CAddrDB::pchMessageStart magic number) and
+        // de-serialize file header (network specific magic number) and ..
         ssPeers >> FLATDATA(pchMsgTmp);
 
-        // verify the network matches ours
-        if (memcmp(pchMsgTmp, CAddrDB::pchMessageStart, sizeof(pchMsgTmp)))
+        // ... verify the network matches ours
+        if (memcmp(pchMsgTmp, Params().MessageStart(), sizeof(pchMsgTmp)))
             return error("CAddrman::Read() : invalid network magic number");
 
         // de-serialize address data into one CAddrMan object
diff --git a/src/db.h b/src/db.h
index 92241f6cf2..b3f269f3da 100644
--- a/src/db.h
+++ b/src/db.h
@@ -318,14 +318,10 @@ class CAddrDB
 {
 private:
     boost::filesystem::path pathAddr;
-    static unsigned char pchMessageStart[4];
-
 public:
     CAddrDB();
     bool Write(const CAddrMan& addr);
     bool Read(CAddrMan& addr);
-
-    static void SetMessageStart(unsigned char _pchMessageStart[]) { memcpy(CAddrDB::pchMessageStart, _pchMessageStart, sizeof(CAddrDB::pchMessageStart)); }
 };
 
 #endif // BITCOIN_DB_H
diff --git a/src/init.cpp b/src/init.cpp
index fe74cd6963..4e599048ac 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -6,6 +6,7 @@
 #include "init.h"
 #include "main.h"
 #include "core.h"
+#include "chainparams.h"
 #include "txdb.h"
 #include "walletdb.h"
 #include "bitcoinrpc.h"
@@ -13,6 +14,7 @@
 #include "util.h"
 #include "ui_interface.h"
 #include "checkpoints.h"
+#include "chainparams.h"
 
 #include <boost/filesystem.hpp>
 #include <boost/filesystem/fstream.hpp>
@@ -210,6 +212,8 @@ std::string HelpMessage()
     strUsage += "  -logtimestamps         " + _("Prepend debug output with timestamp") + "\n";
     strUsage += "  -shrinkdebugfile       " + _("Shrink debug.log file on client startup (default: 1 when no -debug)") + "\n";
     strUsage += "  -printtoconsole        " + _("Send trace/debug info to console instead of debug.log file") + "\n";
+    strUsage += "  -regtest               " + _("Enter regression test mode, which uses a special chain in which blocks can be "
+                                                "solved instantly. This is intended for regression testing tools and app development.") + "\n";
 #ifdef WIN32
     strUsage += "  -printtodebugger       " + _("Send trace/debug info to debugger") + "\n";
 #endif
@@ -366,8 +370,10 @@ bool AppInit2(boost::thread_group& threadGroup)
 
     // ********************************************************* Step 2: parameter interactions
 
-    fTestNet = GetBoolArg("-testnet", false);
     Checkpoints::fEnabled = GetBoolArg("-checkpoints", true);
+    if (!SelectParamsFromCommandLine()) {
+        return InitError("Invalid combination of -testnet and -regtest.");
+    }
 
     if (mapArgs.count("-bind")) {
         // when specifying an explicit binding address, you want to listen on it
@@ -572,7 +578,7 @@ bool AppInit2(boost::thread_group& threadGroup)
     // ********************************************************* Step 6: network initialization
 
     RegisterNodeSignals(GetNodeSignals());
- 
+
     int nSocksVersion = GetArg("-socks", 5);
     if (nSocksVersion != 4 && nSocksVersion != 5)
         return InitError(strprintf(_("Unknown -socks proxy version requested: %i"), nSocksVersion));
@@ -937,7 +943,6 @@ bool AppInit2(boost::thread_group& threadGroup)
     nStart = GetTimeMillis();
 
     {
-        CAddrDB::SetMessageStart(pchMessageStart);
         CAddrDB adb;
         if (!adb.Read(addrman))
             printf("Invalid or missing peers.dat; recreating\n");
diff --git a/src/main.cpp b/src/main.cpp
index f0c08d273f..975e0f6e6c 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -11,6 +11,7 @@
 #include "init.h"
 #include "ui_interface.h"
 #include "checkqueue.h"
+#include "chainparams.h"
 #include <boost/algorithm/string/replace.hpp>
 #include <boost/filesystem.hpp>
 #include <boost/filesystem/fstream.hpp>
@@ -32,8 +33,6 @@ unsigned int nTransactionsUpdated = 0;
 
 map<uint256, CBlockIndex*> mapBlockIndex;
 std::vector<CBlockIndex*> vBlockIndexByHeight;
-uint256 hashGenesisBlock("0x000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f");
-static CBigNum bnProofOfWorkLimit(~uint256(0) >> 32);
 CBlockIndex* pindexGenesisBlock = NULL;
 int nBestHeight = -1;
 uint256 nBestChainWork = 0;
@@ -158,8 +157,6 @@ void static ResendWalletTransactions()
         pwallet->ResendWalletTransactions();
 }
 
-
-
 //////////////////////////////////////////////////////////////////////////////
 //
 // Registration of network node signals.
@@ -177,7 +174,95 @@ void UnregisterNodeSignals(CNodeSignals& nodeSignals)
     nodeSignals.SendMessages.disconnect(&SendMessages);
 }
 
+//////////////////////////////////////////////////////////////////////////////
+//
+// CBlockLocator implementation
+//
+
+CBlockLocator::CBlockLocator(uint256 hashBlock)
+{
+    std::map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(hashBlock);
+    if (mi != mapBlockIndex.end())
+        Set((*mi).second);
+}
+
+void CBlockLocator::Set(const CBlockIndex* pindex)
+{
+    vHave.clear();
+    int nStep = 1;
+    while (pindex)
+    {
+        vHave.push_back(pindex->GetBlockHash());
+
+        // Exponentially larger steps back
+        for (int i = 0; pindex && i < nStep; i++)
+            pindex = pindex->pprev;
+        if (vHave.size() > 10)
+            nStep *= 2;
+    }
+    vHave.push_back(Params().HashGenesisBlock());
+}
+
+int CBlockLocator::GetDistanceBack()
+{
+    // Retrace how far back it was in the sender's branch
+    int nDistance = 0;
+    int nStep = 1;
+    BOOST_FOREACH(const uint256& hash, vHave)
+    {
+        std::map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(hash);
+        if (mi != mapBlockIndex.end())
+        {
+            CBlockIndex* pindex = (*mi).second;
+            if (pindex->IsInMainChain())
+                return nDistance;
+        }
+        nDistance += nStep;
+        if (nDistance > 10)
+            nStep *= 2;
+    }
+    return nDistance;
+}
 
+CBlockIndex *CBlockLocator::GetBlockIndex()
+{
+    // Find the first block the caller has in the main chain
+    BOOST_FOREACH(const uint256& hash, vHave)
+    {
+        std::map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(hash);
+        if (mi != mapBlockIndex.end())
+        {
+            CBlockIndex* pindex = (*mi).second;
+            if (pindex->IsInMainChain())
+                return pindex;
+        }
+    }
+    return pindexGenesisBlock;
+}
+
+uint256 CBlockLocator::GetBlockHash()
+{
+    // Find the first block the caller has in the main chain
+    BOOST_FOREACH(const uint256& hash, vHave)
+    {
+        std::map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(hash);
+        if (mi != mapBlockIndex.end())
+        {
+            CBlockIndex* pindex = (*mi).second;
+            if (pindex->IsInMainChain())
+                return hash;
+        }
+    }
+    return Params().HashGenesisBlock();
+}
+
+int CBlockLocator::GetHeight()
+{
+    CBlockIndex* pindex = GetBlockIndex();
+    if (!pindex)
+        return 0;
+    return pindex->nHeight;
+}
 
 //////////////////////////////////////////////////////////////////////////////
 //
@@ -712,7 +797,7 @@ bool CTxMemPool::accept(CValidationState &state, CTransaction &tx, bool fLimitFr
         return error("CTxMemPool::accept() : not accepting nLockTime beyond 2038 yet");
 
     // Rather not work on nonstandard transactions (unless -testnet)
-    if (!fTestNet && !IsStandardTx(tx))
+    if (!TestNet() && !IsStandardTx(tx))
         return error("CTxMemPool::accept() : nonstandard transaction type");
 
     // is it already in the memory pool?
@@ -787,7 +872,7 @@ bool CTxMemPool::accept(CValidationState &state, CTransaction &tx, bool fLimitFr
         }
 
         // Check for non-standard pay-to-script-hash in inputs
-        if (!AreInputsStandard(tx, view) && !fTestNet)
+        if (!TestNet() && !AreInputsStandard(tx, view))
             return error("CTxMemPool::accept() : nonstandard transaction input");
 
         // Note: if you modify this code to accept non-standard transactions, then
@@ -1097,8 +1182,8 @@ int64 static GetBlockValue(int nHeight, int64 nFees)
 {
     int64 nSubsidy = 50 * COIN;
 
-    // Subsidy is cut in half every 210000 blocks, which will occur approximately every 4 years
-    nSubsidy >>= (nHeight / 210000);
+    // Subsidy is cut in half every 210,000 blocks which will occur approximately every 4 years.
+    nSubsidy >>= (nHeight / Params().SubsidyHalvingInterval());
 
     return nSubsidy + nFees;
 }
@@ -1113,28 +1198,29 @@ static const int64 nInterval = nTargetTimespan / nTargetSpacing;
 //
 unsigned int ComputeMinWork(unsigned int nBase, int64 nTime)
 {
+    const CBigNum &bnLimit = Params().ProofOfWorkLimit();
     // Testnet has min-difficulty blocks
     // after nTargetSpacing*2 time between blocks:
-    if (fTestNet && nTime > nTargetSpacing*2)
-        return bnProofOfWorkLimit.GetCompact();
+    if (TestNet() && nTime > nTargetSpacing*2)
+        return bnLimit.GetCompact();
 
     CBigNum bnResult;
     bnResult.SetCompact(nBase);
-    while (nTime > 0 && bnResult < bnProofOfWorkLimit)
+    while (nTime > 0 && bnResult < bnLimit)
     {
         // Maximum 400% adjustment...
         bnResult *= 4;
         // ... in best-case exactly 4-times-normal target time
         nTime -= nTargetTimespan*4;
     }
-    if (bnResult > bnProofOfWorkLimit)
-        bnResult = bnProofOfWorkLimit;
+    if (bnResult > bnLimit)
+        bnResult = bnLimit;
     return bnResult.GetCompact();
 }
 
 unsigned int static GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHeader *pblock)
 {
-    unsigned int nProofOfWorkLimit = bnProofOfWorkLimit.GetCompact();
+    unsigned int nProofOfWorkLimit = Params().ProofOfWorkLimit().GetCompact();
 
     // Genesis block
     if (pindexLast == NULL)
@@ -1143,9 +1229,9 @@ unsigned int static GetNextWorkRequired(const CBlockIndex* pindexLast, const CBl
     // Only change once per interval
     if ((pindexLast->nHeight+1) % nInterval != 0)
     {
-        // Special difficulty rule for testnet:
-        if (fTestNet)
+        if (TestNet())
         {
+            // Special difficulty rule for testnet:
             // If the new block's timestamp is more than 2* 10 minutes
             // then allow mining of a min-difficulty block.
             if (pblock->nTime > pindexLast->nTime + nTargetSpacing*2)
@@ -1159,7 +1245,6 @@ unsigned int static GetNextWorkRequired(const CBlockIndex* pindexLast, const CBl
                 return pindex->nBits;
             }
         }
-
         return pindexLast->nBits;
     }
 
@@ -1183,8 +1268,8 @@ unsigned int static GetNextWorkRequired(const CBlockIndex* pindexLast, const CBl
     bnNew *= nActualTimespan;
     bnNew /= nTargetTimespan;
 
-    if (bnNew > bnProofOfWorkLimit)
-        bnNew = bnProofOfWorkLimit;
+    if (bnNew > Params().ProofOfWorkLimit())
+        bnNew = Params().ProofOfWorkLimit();
 
     /// debug print
     printf("GetNextWorkRequired RETARGET\n");
@@ -1201,7 +1286,7 @@ bool CheckProofOfWork(uint256 hash, unsigned int nBits)
     bnTarget.SetCompact(nBits);
 
     // Check range
-    if (bnTarget <= 0 || bnTarget > bnProofOfWorkLimit)
+    if (bnTarget <= 0 || bnTarget > Params().ProofOfWorkLimit())
         return error("CheckProofOfWork() : nBits below minimum work");
 
     // Check proof of work matches claimed amount
@@ -1319,7 +1404,7 @@ void UpdateTime(CBlockHeader& block, const CBlockIndex* pindexPrev)
     block.nTime = max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime());
 
     // Updating time can change work required on testnet:
-    if (fTestNet)
+    if (TestNet())
         block.nBits = GetNextWorkRequired(pindexPrev, &block);
 }
 
@@ -1608,7 +1693,7 @@ bool CBlock::ConnectBlock(CValidationState &state, CBlockIndex* pindex, CCoinsVi
 
     // Special case for the genesis block, skipping connection of its transactions
     // (its coinbase is unspendable)
-    if (GetHash() == hashGenesisBlock) {
+    if (GetHash() == Params().HashGenesisBlock()) {
         view.SetBestBlock(pindex);
         pindexGenesisBlock = pindex;
         return true;
@@ -2136,7 +2221,7 @@ bool CBlock::AcceptBlock(CValidationState &state, CDiskBlockPos *dbp)
     // Get prev block index
     CBlockIndex* pindexPrev = NULL;
     int nHeight = 0;
-    if (hash != hashGenesisBlock) {
+    if (hash != Params().HashGenesisBlock()) {
         map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(hashPrevBlock);
         if (mi == mapBlockIndex.end())
             return state.DoS(10, error("AcceptBlock() : prev block not found"));
@@ -2163,8 +2248,8 @@ bool CBlock::AcceptBlock(CValidationState &state, CDiskBlockPos *dbp)
         // Reject block.nVersion=1 blocks when 95% (75% on testnet) of the network has upgraded:
         if (nVersion < 2)
         {
-            if ((!fTestNet && CBlockIndex::IsSuperMajority(2, pindexPrev, 950, 1000)) ||
-                (fTestNet && CBlockIndex::IsSuperMajority(2, pindexPrev, 75, 100)))
+            if ((!TestNet() && CBlockIndex::IsSuperMajority(2, pindexPrev, 950, 1000)) ||
+                (TestNet() && CBlockIndex::IsSuperMajority(2, pindexPrev, 75, 100)))
             {
                 return state.Invalid(error("AcceptBlock() : rejected nVersion=1 block"));
             }
@@ -2173,8 +2258,8 @@ bool CBlock::AcceptBlock(CValidationState &state, CDiskBlockPos *dbp)
         if (nVersion >= 2)
         {
             // if 750 of the last 1,000 blocks are version 2 or greater (51/100 if testnet):
-            if ((!fTestNet && CBlockIndex::IsSuperMajority(2, pindexPrev, 750, 1000)) ||
-                (fTestNet && CBlockIndex::IsSuperMajority(2, pindexPrev, 51, 100)))
+            if ((!TestNet() && CBlockIndex::IsSuperMajority(2, pindexPrev, 750, 1000)) ||
+                (TestNet() && CBlockIndex::IsSuperMajority(2, pindexPrev, 51, 100)))
             {
                 CScript expect = CScript() << nHeight;
                 if (!std::equal(expect.begin(), expect.end(), vtx[0].vin[0].scriptSig.begin()))
@@ -2704,21 +2789,9 @@ void UnloadBlockIndex()
 
 bool LoadBlockIndex()
 {
-    if (fTestNet)
-    {
-        pchMessageStart[0] = 0x0b;
-        pchMessageStart[1] = 0x11;
-        pchMessageStart[2] = 0x09;
-        pchMessageStart[3] = 0x07;
-        hashGenesisBlock = uint256("000000000933ea01ad0ee984209779baaec3ced90fa3f408719526f8d77f4943");
-    }
-
-    //
     // Load block index from databases
-    //
     if (!fReindex && !LoadBlockIndexDB())
         return false;
-
     return true;
 }
 
@@ -2735,47 +2808,9 @@ bool InitBlockIndex() {
 
     // Only add the genesis block if not reindexing (in which case we reuse the one already on disk)
     if (!fReindex) {
-        // Genesis Block:
-        // CBlock(hash=000000000019d6, ver=1, hashPrevBlock=00000000000000, hashMerkleRoot=4a5e1e, nTime=1231006505, nBits=1d00ffff, nNonce=2083236893, vtx=1)
-        //   CTransaction(hash=4a5e1e, ver=1, vin.size=1, vout.size=1, nLockTime=0)
-        //     CTxIn(COutPoint(000000, -1), coinbase 04ffff001d0104455468652054696d65732030332f4a616e2f32303039204368616e63656c6c6f72206f6e206272696e6b206f66207365636f6e64206261696c6f757420666f722062616e6b73)
-        //     CTxOut(nValue=50.00000000, scriptPubKey=0x5F1DF16B2B704C8A578D0B)
-        //   vMerkleTree: 4a5e1e
-
-        // Genesis block
-        const char* pszTimestamp = "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks";
-        CTransaction txNew;
-        txNew.vin.resize(1);
-        txNew.vout.resize(1);
-        txNew.vin[0].scriptSig = CScript() << 486604799 << CBigNum(4) << vector<unsigned char>((const unsigned char*)pszTimestamp, (const unsigned char*)pszTimestamp + strlen(pszTimestamp));
-        txNew.vout[0].nValue = 50 * COIN;
-        txNew.vout[0].scriptPubKey = CScript() << ParseHex("04678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef38c4f35504e51ec112de5c384df7ba0b8d578a4c702b6bf11d5f") << OP_CHECKSIG;
-        CBlock block;
-        block.vtx.push_back(txNew);
-        block.hashPrevBlock = 0;
-        block.hashMerkleRoot = block.BuildMerkleTree();
-        block.nVersion = 1;
-        block.nTime    = 1231006505;
-        block.nBits    = 0x1d00ffff;
-        block.nNonce   = 2083236893;
-
-        if (fTestNet)
-        {
-            block.nTime    = 1296688602;
-            block.nNonce   = 414098458;
-        }
-
-        //// debug print
-        uint256 hash = block.GetHash();
-        printf("%s\n", hash.ToString().c_str());
-        printf("%s\n", hashGenesisBlock.ToString().c_str());
-        printf("%s\n", block.hashMerkleRoot.ToString().c_str());
-        assert(block.hashMerkleRoot == uint256("0x4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b"));
-        block.print();
-        assert(hash == hashGenesisBlock);
-
-        // Start new block file
         try {
+            CBlock &block = const_cast<CBlock&>(Params().GenesisBlock());
+            // Start new block file
             unsigned int nBlockSize = ::GetSerializeSize(block, SER_DISK, CLIENT_VERSION);
             CDiskBlockPos blockPos;
             CValidationState state;
@@ -2892,10 +2927,10 @@ bool LoadExternalBlockFile(FILE* fileIn, CDiskBlockPos *dbp)
             try {
                 // locate a header
                 unsigned char buf[4];
-                blkdat.FindByte(pchMessageStart[0]);
+                blkdat.FindByte(Params().MessageStart()[0]);
                 nRewind = blkdat.GetPos()+1;
                 blkdat >> FLATDATA(buf);
-                if (memcmp(buf, pchMessageStart, 4))
+                if (memcmp(buf, Params().MessageStart(), 4))
                     continue;
                 // read size
                 blkdat >> nSize;
@@ -3040,12 +3075,6 @@ bool static AlreadyHave(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] = { 0xf9, 0xbe, 0xb4, 0xd9 };
-
-
 void static ProcessGetData(CNode* pfrom)
 {
     std::deque<CInv>::iterator it = pfrom->vRecvGetData.begin();
@@ -3768,7 +3797,7 @@ bool ProcessMessages(CNode* pfrom)
         it++;
 
         // Scan for message start
-        if (memcmp(msg.hdr.pchMessageStart, pchMessageStart, sizeof(pchMessageStart)) != 0) {
+        if (memcmp(msg.hdr.pchMessageStart, Params().MessageStart(), MESSAGE_START_SIZE) != 0) {
             printf("\n\nPROCESSMESSAGE: INVALID MESSAGESTART\n\n");
             fOk = false;
             break;
@@ -4512,8 +4541,12 @@ void static BitcoinMiner(CWallet *pwallet)
     unsigned int nExtraNonce = 0;
 
     try { loop {
-        while (vNodes.empty())
-            MilliSleep(1000);
+        if (Params().NetworkID() != CChainParams::REGTEST) {
+            // Busy-wait for the network to come online so we don't waste time mining
+            // on an obsolete chain. In regtest mode we expect to fly solo.
+            while (vNodes.empty())
+                MilliSleep(1000);
+        }
 
         //
         // Create new block
@@ -4575,6 +4608,12 @@ void static BitcoinMiner(CWallet *pwallet)
                     SetThreadPriority(THREAD_PRIORITY_NORMAL);
                     CheckWork(pblock, *pwalletMain, reservekey);
                     SetThreadPriority(THREAD_PRIORITY_LOWEST);
+
+                    // In regression test mode, stop mining after a block is found. This
+                    // allows developers to controllably generate a block on demand.
+                    if (Params().NetworkID() == CChainParams::REGTEST)
+                        throw boost::thread_interrupted();
+
                     break;
                 }
             }
@@ -4610,7 +4649,7 @@ void static BitcoinMiner(CWallet *pwallet)
 
             // Check for stop or if block needs to be rebuilt
             boost::this_thread::interruption_point();
-            if (vNodes.empty())
+            if (vNodes.empty() && Params().NetworkID() != CChainParams::REGTEST)
                 break;
             if (nBlockNonce >= 0xffff0000)
                 break;
@@ -4622,7 +4661,7 @@ void static BitcoinMiner(CWallet *pwallet)
             // Update nTime every few seconds
             UpdateTime(*pblock, pindexPrev);
             nBlockTime = ByteReverse(pblock->nTime);
-            if (fTestNet)
+            if (TestNet())
             {
                 // Changing pblock->nTime can change work required on testnet:
                 nBlockBits = ByteReverse(pblock->nBits);
@@ -4642,8 +4681,12 @@ void GenerateBitcoins(bool fGenerate, CWallet* pwallet)
     static boost::thread_group* minerThreads = NULL;
 
     int nThreads = GetArg("-genproclimit", -1);
-    if (nThreads < 0)
-        nThreads = boost::thread::hardware_concurrency();
+    if (nThreads < 0) {
+        if (Params().NetworkID() == CChainParams::REGTEST)
+            nThreads = 1;
+        else
+            nThreads = boost::thread::hardware_concurrency();
+    }
 
     if (minerThreads != NULL)
     {
diff --git a/src/main.h b/src/main.h
index 87f1dbfa8f..ec89d8bdd3 100644
--- a/src/main.h
+++ b/src/main.h
@@ -70,7 +70,6 @@ extern CCriticalSection cs_main;
 extern std::map<uint256, CBlockIndex*> mapBlockIndex;
 extern std::vector<CBlockIndex*> vBlockIndexByHeight;
 extern std::set<CBlockIndex*, CBlockIndexWorkComparator> setBlockIndexValid;
-extern uint256 hashGenesisBlock;
 extern CBlockIndex* pindexGenesisBlock;
 extern int nBestHeight;
 extern uint256 nBestChainWork;
@@ -86,7 +85,6 @@ extern int64 nHPSTimerStart;
 extern int64 nTimeBestReceived;
 extern CCriticalSection cs_setpwalletRegistered;
 extern std::set<CWallet*> setpwalletRegistered;
-extern unsigned char pchMessageStart[4];
 extern bool fImporting;
 extern bool fReindex;
 extern bool fBenchmark;
@@ -353,7 +351,7 @@ public:
 
         // Write index header
         unsigned int nSize = fileout.GetSerializeSize(*this);
-        fileout << FLATDATA(pchMessageStart) << nSize;
+        fileout << FLATDATA(Params().MessageStart()) << nSize;
 
         // Write undo data
         long fileOutPos = ftell(fileout);
@@ -692,7 +690,7 @@ public:
 
         // Write index header
         unsigned int nSize = fileout.GetSerializeSize(*this);
-        fileout << FLATDATA(pchMessageStart) << nSize;
+        fileout << FLATDATA(Params().MessageStart()) << nSize;
 
         // Write block
         long fileOutPos = ftell(fileout);
@@ -1202,22 +1200,14 @@ class CBlockLocator
 protected:
     std::vector<uint256> vHave;
 public:
-
-    CBlockLocator()
-    {
-    }
+    CBlockLocator() {}
 
     explicit CBlockLocator(const CBlockIndex* pindex)
     {
         Set(pindex);
     }
 
-    explicit CBlockLocator(uint256 hashBlock)
-    {
-        std::map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(hashBlock);
-        if (mi != mapBlockIndex.end())
-            Set((*mi).second);
-    }
+    explicit CBlockLocator(uint256 hashBlock);
 
     CBlockLocator(const std::vector<uint256>& vHaveIn)
     {
@@ -1241,83 +1231,16 @@ public:
         return vHave.empty();
     }
 
-    void Set(const CBlockIndex* pindex)
-    {
-        vHave.clear();
-        int nStep = 1;
-        while (pindex)
-        {
-            vHave.push_back(pindex->GetBlockHash());
-
-            // Exponentially larger steps back
-            for (int i = 0; pindex && i < nStep; i++)
-                pindex = pindex->pprev;
-            if (vHave.size() > 10)
-                nStep *= 2;
-        }
-        vHave.push_back(hashGenesisBlock);
-    }
-
-    int GetDistanceBack()
-    {
-        // Retrace how far back it was in the sender's branch
-        int nDistance = 0;
-        int nStep = 1;
-        BOOST_FOREACH(const uint256& hash, vHave)
-        {
-            std::map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(hash);
-            if (mi != mapBlockIndex.end())
-            {
-                CBlockIndex* pindex = (*mi).second;
-                if (pindex->IsInMainChain())
-                    return nDistance;
-            }
-            nDistance += nStep;
-            if (nDistance > 10)
-                nStep *= 2;
-        }
-        return nDistance;
-    }
-
-    CBlockIndex* GetBlockIndex()
-    {
-        // Find the first block the caller has in the main chain
-        BOOST_FOREACH(const uint256& hash, vHave)
-        {
-            std::map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(hash);
-            if (mi != mapBlockIndex.end())
-            {
-                CBlockIndex* pindex = (*mi).second;
-                if (pindex->IsInMainChain())
-                    return pindex;
-            }
-        }
-        return pindexGenesisBlock;
-    }
-
-    uint256 GetBlockHash()
-    {
-        // Find the first block the caller has in the main chain
-        BOOST_FOREACH(const uint256& hash, vHave)
-        {
-            std::map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(hash);
-            if (mi != mapBlockIndex.end())
-            {
-                CBlockIndex* pindex = (*mi).second;
-                if (pindex->IsInMainChain())
-                    return hash;
-            }
-        }
-        return hashGenesisBlock;
-    }
-
-    int GetHeight()
-    {
-        CBlockIndex* pindex = GetBlockIndex();
-        if (!pindex)
-            return 0;
-        return pindex->nHeight;
-    }
+    /** Given a block initialises the locator to that point in the chain. */
+    void Set(const CBlockIndex* pindex);
+    /** Returns the distance in blocks this locator is from our chain head. */
+    int GetDistanceBack();
+    /** Returns the first best-chain block the locator contains. */
+    CBlockIndex* GetBlockIndex();
+    /** Returns the hash of the first best chain block the locator contains. */
+    uint256 GetBlockHash();
+    /** Returns the height of the first best chain block the locator has. */
+    int GetHeight();
 };
 
 
diff --git a/src/makefile.unix b/src/makefile.unix
index a83bab1047..f17de05cb9 100644
--- a/src/makefile.unix
+++ b/src/makefile.unix
@@ -143,7 +143,8 @@ OBJS= \
     obj/bloom.o \
     obj/noui.o \
     obj/leveldb.o \
-    obj/txdb.o
+    obj/txdb.o \
+    obj/chainparams.o
 
 
 all: bitcoind
diff --git a/src/net.cpp b/src/net.cpp
index 1d181823e2..0adf26ef0d 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -3,6 +3,7 @@
 // Distributed under the MIT/X11 software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include "chainparams.h"
 #include "db.h"
 #include "net.h"
 #include "core.h"
@@ -80,7 +81,7 @@ void AddOneShot(string strDest)
 
 unsigned short GetListenPort()
 {
-    return (unsigned short)(GetArg("-port", GetDefaultPort()));
+    return (unsigned short)(GetArg("-port", Params().GetDefaultPort()));
 }
 
 // find 'best' local address for a particular peer
@@ -464,7 +465,7 @@ CNode* ConnectNode(CAddress addrConnect, const char *pszDest)
 
     // Connect
     SOCKET hSocket;
-    if (pszDest ? ConnectSocketByName(addrConnect, hSocket, pszDest, GetDefaultPort()) : ConnectSocket(addrConnect, hSocket))
+    if (pszDest ? ConnectSocketByName(addrConnect, hSocket, pszDest, Params().GetDefaultPort()) : ConnectSocket(addrConnect, hSocket))
     {
         addrman.Attempt(addrConnect);
 
@@ -1170,53 +1171,31 @@ void MapPort(bool)
 
 
 
-
-
-
-// DNS seeds
-// Each pair gives a source name and a seed name.
-// The first name is used as information source for addrman.
-// The second name should resolve to a list of seed addresses.
-static const char *strMainNetDNSSeed[][2] = {
-    {"bitcoin.sipa.be", "seed.bitcoin.sipa.be"},
-    {"bluematt.me", "dnsseed.bluematt.me"},
-    {"dashjr.org", "dnsseed.bitcoin.dashjr.org"},
-    {"xf2.org", "bitseed.xf2.org"},
-    {NULL, NULL}
-};
-
-static const char *strTestNetDNSSeed[][2] = {
-    {"bitcoin.petertodd.org", "testnet-seed.bitcoin.petertodd.org"},
-    {"bluematt.me", "testnet-seed.bluematt.me"},
-    {NULL, NULL}
-};
-
 void ThreadDNSAddressSeed()
 {
-    static const char *(*strDNSSeed)[2] = fTestNet ? strTestNetDNSSeed : strMainNetDNSSeed;
-
+    const vector<CDNSSeedData> &vSeeds = Params().DNSSeeds();
     int found = 0;
 
     printf("Loading addresses from DNS seeds (could take a while)\n");
 
-    for (unsigned int seed_idx = 0; strDNSSeed[seed_idx][0] != NULL; seed_idx++) {
+    BOOST_FOREACH(const CDNSSeedData &seed, vSeeds) {
         if (HaveNameProxy()) {
-            AddOneShot(strDNSSeed[seed_idx][1]);
+            AddOneShot(seed.host);
         } else {
-            vector<CNetAddr> vaddr;
+            vector<CNetAddr> vIPs;
             vector<CAddress> vAdd;
-            if (LookupHost(strDNSSeed[seed_idx][1], vaddr))
+            if (LookupHost(seed.host.c_str(), vIPs))
             {
-                BOOST_FOREACH(CNetAddr& ip, vaddr)
+                BOOST_FOREACH(CNetAddr& ip, vIPs)
                 {
                     int nOneDay = 24*3600;
-                    CAddress addr = CAddress(CService(ip, GetDefaultPort()));
+                    CAddress addr = CAddress(CService(ip, Params().GetDefaultPort()));
                     addr.nTime = GetTime() - 3*nOneDay - GetRand(4*nOneDay); // use a random age between 3 and 7 days old
                     vAdd.push_back(addr);
                     found++;
                 }
             }
-            addrman.Add(vAdd, CNetAddr(strDNSSeed[seed_idx][0], true));
+            addrman.Add(vAdd, CNetAddr(seed.name, true));
         }
     }
 
@@ -1234,85 +1213,6 @@ void ThreadDNSAddressSeed()
 
 
 
-unsigned int pnSeed[] =
-{
-    0xe473042e, 0xb177f2ad, 0xd63f3fb2, 0xf864f736, 0x44a23ac7, 0xcf6d9650, 0xd648042e, 0x0536f447,
-    0x3c654ed0, 0x3e16a5bc, 0xa38e09b0, 0xdfae795b, 0xabfeca5b, 0x94ad7840, 0xf3b9f1c7, 0xbe70e0ad,
-    0x3bbd09b0, 0x8d0c7dd5, 0x3b2a7332, 0x1a06175e, 0x581f175e, 0xca0d2dcc, 0x0fdbc658, 0xcf591ec7,
-    0x295a12b2, 0xb4707bce, 0x68bb09b0, 0x4e735747, 0x89709553, 0x05a7814e, 0x5b8ec658, 0x402c5512,
-    0xe80d0905, 0x17681a5e, 0xc02aa748, 0x9f811741, 0x5f321cb0, 0x23e1ee47, 0xaf7f170c, 0xaa240ab0,
-    0xedea6257, 0x76106bc1, 0x2cf310cc, 0x08612acb, 0x9c682e4e, 0x8e963c6c, 0x443c795b, 0x22e246b8,
-    0xfa1f2dcc, 0x90118140, 0x3821042e, 0x33c3fd2e, 0x10046d5b, 0x40d14b3e, 0x7fb8f8ce, 0x67696550,
-    0xeeecbe58, 0x4f341745, 0x46b8fbd5, 0xc8463932, 0x6b73e862, 0x4c715932, 0x4a6785d5, 0xce3a64c2,
-    0xde9604c7, 0x9b06884f, 0x18002a45, 0xea9bc345, 0xc4f1c658, 0xe475c1c7, 0xdd3e795b, 0x9722175e,
-    0x34562f4e, 0x66c46e4e, 0x40bb1243, 0x7d9171d0, 0x17b8dbd5, 0x63cbfd2e, 0x1a08b8d8, 0x6175a73b,
-    0x228d2660, 0x8627c658, 0x9c566644, 0x38cca5bc, 0x3089de5b, 0x92e25f5d, 0xa393f73f, 0xcc92dc3e,
-    0x27487446, 0x62cbfd2e, 0x9d983b45, 0xf72a09b0, 0xf75f042e, 0x6434bb6a, 0xb29e77d8, 0x19be4fd9,
-    0x76443243, 0x9dd72645, 0x694cef43, 0x89c2efd5, 0x5f1c5058, 0x46c6e45b, 0xe1391b40, 0x77ccefd5,
-    0x472e5a6d, 0x85709553, 0xdd4f5d4c, 0x64ef5a46, 0x7f0ae502, 0xcf08d850, 0x3460042e, 0xeafa2d42,
-    0x793c9044, 0x9d094746, 0x1ab9b153, 0xbfe9a5bc, 0x34771fb0, 0xb7722e32, 0x1168964b, 0x19b06ab8,
-    0x19243b25, 0x13188045, 0xb4070905, 0x728ebb5d, 0x44f24ac8, 0xa317fead, 0x642f6a57, 0x3d951f32,
-    0x3d312e4e, 0xfac4d048, 0xefc4dd50, 0x52b9f1c7, 0xc14d3cc3, 0x0219ea44, 0x3b79d058, 0xfa217242,
-    0x39c80647, 0xfb697252, 0x1d495a42, 0x0aa81f4e, 0x58249ab8, 0xe6a8e6c3, 0x2bc4dad8, 0x85963c6c,
-    0xa4ce09b0, 0x2005f536, 0x5cc2703e, 0x1992de43, 0x74e86b4c, 0xe7085653, 0xf5e15a51, 0xb4872b60,
-    0x29e2b162, 0xa07ea053, 0x8229fd18, 0x4562ec4d, 0x8dec814e, 0x36cfa4cf, 0x96461032, 0x3c8770de,
-    0xd10a1f5f, 0x95934641, 0x97cd65d0, 0x2e35324a, 0x2566ba1f, 0x1ca1a9d1, 0xb808b8d5, 0xf9a24a5d,
-    0xafc8d431, 0xe4b8d9b2, 0x0f5321b2, 0x330bc658, 0x74b347ce, 0x972babd5, 0x044f7d4f, 0x06562f4e,
-    0x8b8d3c6c, 0x3507c658, 0xe4174e4d, 0xf1c009b0, 0x52249ab8, 0x27211772, 0xf6a9ba59, 0x7a391b40,
-    0x855dc6c0, 0x291f20b2, 0xe29bc345, 0x90963c6c, 0x0af70732, 0x4242a91f, 0x4c531d48, 0xa32df948,
-    0x627e3044, 0x65be1f54, 0x1a0cbf83, 0x6a443532, 0x8d5f1955, 0xbafa8132, 0x3534bdd5, 0xca019dd9,
-    0x8a0d9332, 0x5584e7d8, 0x7cd1f25e, 0xeabe3fb2, 0x2945d0d1, 0x46415718, 0x70d6042e, 0x99eb76d0,
-    0x9ece09b0, 0xb3777418, 0x5e5e91d9, 0x237a3ab0, 0xf512b62e, 0x45dec347, 0x59b7f862, 0x4c443b25,
-    0x3cc6484b, 0x9a8ec6d1, 0x021eea44, 0xc9483944, 0xfd567e32, 0xfd204bb2, 0xc5330bcc, 0x5202894e,
-    0xf9e309b0, 0x4cc17557, 0xdb9064ae, 0xe19e77d8, 0x25857f60, 0xeb4a15ad, 0x1f47f554, 0xea4472d9,
-    0xd20de593, 0xf5733b25, 0x11892b54, 0x5729d35f, 0xe6188cd1, 0x488b132e, 0x541c534a, 0xa8e854ae,
-    0xa255a66c, 0x33688763, 0xc6629ac6, 0xc20a6265, 0xcd92a059, 0x72029d3b, 0x4c298f5e, 0x51452e4e,
-    0xbb065058, 0x15fd2dcc, 0xf40c135e, 0x615a0bad, 0x0c6a6805, 0x4971a7ad, 0x17f2a5d5, 0xf8babf47,
-    0xb61f50ad, 0x4e1451b1, 0xf72d9252, 0x5c2abe58, 0xbd987c61, 0x084ae5cf, 0x20781fb0, 0x38b0f160,
-    0x18aac705, 0x14f86dc1, 0x5556f481, 0x0a36c144, 0xeb446e4c, 0x2c1c0d6c, 0xbd0ff860, 0x869f92db,
-    0x36c94f4c, 0x05502444, 0x148fe55b, 0xd5301e59, 0xd57a8f45, 0x110dc04a, 0x8670fc36, 0xee733b25,
-    0xca56f481, 0x2a5c3bae, 0x844b0905, 0x1e51fe53, 0x0241c244, 0x59c0614e, 0x94e70a55, 0x7312fead,
-    0xb735be44, 0xa55d0905, 0x2f63962e, 0x14a4e15b, 0x63f8f05c, 0x62d0d262, 0x3cab41ad, 0x87f1b1cb,
-    0x018da6b8, 0xb3967dd5, 0xcb56f481, 0x685ad718, 0x3b4aeeca, 0x8d106bc1, 0x51180905, 0x72660f48,
-    0x1521a243, 0x5b56f481, 0x6390e560, 0xdd61464e, 0x58353b25, 0x553fc062, 0x27c45d59, 0xacc62e4e,
-    0x0d5a1cd9, 0x7f65f442, 0xbdeef660, 0xf1bd1855, 0xf8473cae, 0x13b120b2, 0x442440d0, 0x53fd4352,
-    0xa305fc57, 0x458be84d, 0x639ce1c3, 0xebaaee47, 0x95e2c247, 0xf056f481, 0x6256f481, 0x1d87c65e,
-    0x0a453418, 0x5beb175e, 0xd64f1618, 0xc360795b, 0x2fbf5753, 0xa8c58e53, 0x651cec52, 0x9d37b043,
-    0x124a9758, 0x5242e4a9, 0x89913c6c, 0x880efe2e, 0x2f2f2f0c, 0x72b26751, 0x2896e46d, 0x80f4166c,
-    0x320d59ad, 0xc50151d0, 0x11a8aa43, 0xccf56057, 0x5fbad118, 0x4719b151, 0x2b5f4bc0, 0x4d7a4a50,
-    0xad06e047, 0x62ef5a46, 0x5aebde58, 0xdf7aa66c, 0x851acb50, 0x66b9a559, 0x3e9bb153, 0xcc512f2e,
-    0xc073b08e, 0xd519be58, 0xe981ea4d, 0x12fd50cb, 0x378739ad, 0x06683cae, 0xa22310b2, 0xc185c705,
-    0x8741b545, 0xa26c8318, 0x22d5bc43, 0x39201ec0, 0x68581e3e, 0xdc9bcf62, 0xd508cc82, 0xb149675b,
-    0x4c9609b0, 0x84feb84c, 0x08291e2e, 0xfd2253b2, 0x1fd269c1, 0xc9483932, 0x4d641fb0, 0x7d37c918,
-    0xa9de20ad, 0x77e2d655, 0x6d421b59, 0xd7668f80, 0xced09b62, 0xa9e5a5bc, 0xa4074e18, 0x60fc5ecc,
-    0x01300148, 0x68062444, 0xb4224847, 0xed3aa443, 0xb772fb43, 0x9f56f481, 0x220dfd18, 0x8e1c3d6c,
-    0xc44f09b0, 0x7df2bb73, 0xe22fb844, 0xea534242, 0xb6a755d4, 0xa036654b, 0x138ece5b, 0xda65d3c3,
-    0x955871bc, 0x792124b0, 0xfc82594c, 0x851d494b, 0x2c7aee47, 0x26af46b8, 0x1416252e, 0xa8abb944,
-    0x36c49d25, 0x674f645d, 0x363646b8, 0x9e1a2942, 0x66d0c154, 0xc6c2a545, 0x3570f2ad, 0xe7d547c7,
-    0x7d104932, 0x18cb9c18, 0x1dcfa4cf, 0xd156f481, 0x2a02b91f, 0x3eeb3fa8, 0xcac4175e, 0x34146d42,
-    0x994c4d46, 0x5666f440, 0x85d6713e, 0x5ecb296c, 0x0ea0ae46, 0x87e69f42, 0xc58409b0, 0x1f3436ae,
-    0x21dc6a57, 0x4ad1cd42, 0xfb8c1a4c, 0x52d3dab2, 0x3769894b, 0xb52f1c62, 0x3677916d, 0x82b3fe57,
-    0x493d4ac6, 0x9f963c6c, 0x5d91ff60, 0x458e0dad, 0xa49d0947, 0x491a3e18, 0x4aadcd5b, 0x0e46494b,
-    0x1d1610ad, 0x1a10af5d, 0x4956f481, 0x207a3eae, 0x77e73244, 0xfa3b8742, 0x3261fc36, 0xfcebf536,
-    0x1662e836, 0xf655f636, 0xa2dbd0ad, 0x23036693, 0x30448432, 0xa2b03463, 0x30730344, 0x8e4a6882,
-    0x0c50a1cb, 0xc8d8c06b, 0xc9cd6191, 0xf443db50, 0xa9553c50, 0x23145847, 0xc35da66c, 0x29c12a60,
-    0x55c2b447, 0x7434f75c, 0x61660640, 0xde2a7018, 0xc639494c, 0x1c306fce, 0x19b89244, 0xd29a6462,
-    0x462cd1b2, 0x29902f44, 0x2817fa53, 0x21a30905, 0x7777ae46, 0x288443a1, 0x7bee5148, 0xc2a8b043,
-    0xf5c3d35f, 0x2311ef84, 0x57de08a4, 0x6b221bb2, 0xf2625846, 0x4b9e09b0, 0xa24f880e, 0x22b11447,
-    0xb3a0c744, 0x919e77d8, 0xec8b64ae, 0xff5c8d45, 0x7b15b484, 0x32679a5f, 0xba80b62e, 0x05c25c61,
-    0x60014746, 0x5e8fb04c, 0xe67c0905, 0x4329c658, 0xac8fe555, 0xf875e647, 0x67406386, 0x35ceea18,
-    0xbb79484b, 0xd7b9fa62, 0x238209b0, 0x208a1d32, 0x9630995e, 0x039c1318, 0x6e48006c, 0x60582344,
-    0xadbb0150, 0x853fd462, 0x03772e4e, 0x652ce960, 0x49b630ad, 0x9993af43, 0x3735b34b, 0x548a07d9,
-    0x55a44aad, 0xa23d1bcc, 0xfdbb2f4e, 0x530b24a0, 0x0a44b451, 0x6827c657, 0x1f66494b, 0x4e680a47,
-    0x77e7b747, 0xa5eb3fa8, 0x6649764a, 0xd4e76c4b, 0x2c691fb0, 0xf1292e44, 0xc6d6c774, 0x85d23775,
-    0x28275f4d, 0x259ae46d, 0x02424e81, 0x5f16be58, 0xe707c658, 0x49eae5c7, 0xd5d147ad, 0x9a7abdc3,
-    0xe8ac7fc7, 0x84ec3aae, 0xc24942d0, 0x294aa318, 0x08ac3d18, 0x8894042e, 0xb24609b0, 0x9bcaab58,
-    0xc400f712, 0xd5c512b8, 0x2c02cc62, 0x25080fd8, 0xed74a847, 0x18a5ec5e, 0x9850ec6d, 0xf8909758,
-    0x7f56f481, 0x4496f23c, 0xae27784f, 0xcb7cd93e, 0x06e32860, 0x50b9a84f, 0x3660434a, 0x09161f5f,
-    0x900486bc, 0x08055459, 0xe7ec1017, 0x7e39494c, 0x4f443b25, 0x14751a8a, 0x717d03d4, 0xbd0e24d8,
-    0x054b6f56, 0x854c496c, 0xd92a454a, 0xc39bd054, 0x6093614b, 0x9dbad754, 0x5bf0604a, 0x99f22305
-};
-
 void DumpAddresses()
 {
     int64 nStart = GetTimeMillis();
@@ -1374,24 +1274,14 @@ void ThreadOpenConnections()
         CSemaphoreGrant grant(*semOutbound);
         boost::this_thread::interruption_point();
 
-        // Add seed nodes if IRC isn't working
-        if (addrman.size()==0 && (GetTime() - nStart > 60) && !fTestNet)
-        {
-            std::vector<CAddress> vAdd;
-            for (unsigned int i = 0; i < ARRAYLEN(pnSeed); i++)
-            {
-                // It'll only connect to one or two seed nodes because once it connects,
-                // it'll get a pile of addresses with newer timestamps.
-                // Seed nodes are given a random 'last seen time' of between one and two
-                // weeks ago.
-                const int64 nOneWeek = 7*24*60*60;
-                struct in_addr ip;
-                memcpy(&ip, &pnSeed[i], sizeof(ip));
-                CAddress addr(CService(ip, GetDefaultPort()));
-                addr.nTime = GetTime()-GetRand(nOneWeek)-nOneWeek;
-                vAdd.push_back(addr);
+        // Add seed nodes if DNS seeds are all down (an infrastructure attack?).
+        if (addrman.size() == 0 && (GetTime() - nStart > 60)) {
+            static bool done = false;
+            if (!done) {
+                printf("Adding fixed seed nodes as DNS doesn't seem to be available.\n");
+                addrman.Add(Params().FixedSeeds(), CNetAddr("127.0.0.1"));
+                done = true;
             }
-            addrman.Add(vAdd, CNetAddr("127.0.0.1"));
         }
 
         //
@@ -1440,7 +1330,7 @@ void ThreadOpenConnections()
                 continue;
 
             // do not allow non-default ports, unless after 50 invalid addresses selected already
-            if (addr.GetPort() != GetDefaultPort() && nTries < 50)
+            if (addr.GetPort() != Params().GetDefaultPort() && nTries < 50)
                 continue;
 
             addrConnect = addr;
@@ -1490,7 +1380,7 @@ void ThreadOpenAddedConnections()
         BOOST_FOREACH(string& strAddNode, lAddresses)
         {
             vector<CService> vservNode(0);
-            if(Lookup(strAddNode.c_str(), vservNode, GetDefaultPort(), fNameLookup, 0))
+            if(Lookup(strAddNode.c_str(), vservNode, Params().GetDefaultPort(), fNameLookup, 0))
             {
                 lservAddressesToAdd.push_back(vservNode);
                 {
diff --git a/src/protocol.cpp b/src/protocol.cpp
index 1e22467a33..745b4338e4 100644
--- a/src/protocol.cpp
+++ b/src/protocol.cpp
@@ -21,7 +21,7 @@ static const char* ppszTypeName[] =
 
 CMessageHeader::CMessageHeader()
 {
-    memcpy(pchMessageStart, ::pchMessageStart, sizeof(pchMessageStart));
+    memcpy(pchMessageStart, Params().MessageStart(), MESSAGE_START_SIZE);
     memset(pchCommand, 0, sizeof(pchCommand));
     pchCommand[1] = 1;
     nMessageSize = -1;
@@ -30,7 +30,7 @@ CMessageHeader::CMessageHeader()
 
 CMessageHeader::CMessageHeader(const char* pszCommand, unsigned int nMessageSizeIn)
 {
-    memcpy(pchMessageStart, ::pchMessageStart, sizeof(pchMessageStart));
+    memcpy(pchMessageStart, Params().MessageStart(), MESSAGE_START_SIZE);
     strncpy(pchCommand, pszCommand, COMMAND_SIZE);
     nMessageSize = nMessageSizeIn;
     nChecksum = 0;
@@ -47,7 +47,7 @@ std::string CMessageHeader::GetCommand() const
 bool CMessageHeader::IsValid() const
 {
     // Check start string
-    if (memcmp(pchMessageStart, ::pchMessageStart, sizeof(pchMessageStart)) != 0)
+    if (memcmp(pchMessageStart, Params().MessageStart(), MESSAGE_START_SIZE) != 0)
         return false;
 
     // Check the command string for errors
diff --git a/src/protocol.h b/src/protocol.h
index 4998425070..ae541dfdba 100644
--- a/src/protocol.h
+++ b/src/protocol.h
@@ -10,20 +10,12 @@
 #ifndef __INCLUDED_PROTOCOL_H__
 #define __INCLUDED_PROTOCOL_H__
 
+#include "chainparams.h"
 #include "serialize.h"
 #include "netbase.h"
 #include <string>
 #include "uint256.h"
 
-extern bool fTestNet;
-static inline unsigned short GetDefaultPort(const bool testnet = fTestNet)
-{
-    return testnet ? 18333 : 8333;
-}
-
-
-extern unsigned char pchMessageStart[4];
-
 /** Message header.
  * (4) message start.
  * (12) command.
@@ -50,7 +42,6 @@ class CMessageHeader
     // TODO: make private (improves encapsulation)
     public:
         enum {
-            MESSAGE_START_SIZE=sizeof(::pchMessageStart),
             COMMAND_SIZE=12,
             MESSAGE_SIZE_SIZE=sizeof(int),
             CHECKSUM_SIZE=sizeof(int),
diff --git a/src/qt/clientmodel.cpp b/src/qt/clientmodel.cpp
index e8d99a8d45..5cf4dd8111 100644
--- a/src/qt/clientmodel.cpp
+++ b/src/qt/clientmodel.cpp
@@ -5,6 +5,7 @@
 #include "addresstablemodel.h"
 #include "transactiontablemodel.h"
 
+#include "chainparams.h"
 #include "alert.h"
 #include "main.h"
 #include "checkpoints.h"
@@ -110,7 +111,7 @@ void ClientModel::updateAlert(const QString &hash, int status)
 
 bool ClientModel::isTestNet() const
 {
-    return fTestNet;
+    return TestNet();
 }
 
 bool ClientModel::inInitialBlockDownload() const
diff --git a/src/rpcmining.cpp b/src/rpcmining.cpp
index 6f8ac7a112..d0b0a70be4 100644
--- a/src/rpcmining.cpp
+++ b/src/rpcmining.cpp
@@ -3,6 +3,7 @@
 // Distributed under the MIT/X11 software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include "chainparams.h"
 #include "main.h"
 #include "db.h"
 #include "init.h"
@@ -93,7 +94,7 @@ Value getmininginfo(const Array& params, bool fHelp)
     obj.push_back(Pair("genproclimit",     (int)GetArg("-genproclimit", -1)));
     obj.push_back(Pair("hashespersec",     gethashespersec(params, false)));
     obj.push_back(Pair("pooledtx",         (uint64_t)mempool.size()));
-    obj.push_back(Pair("testnet",          fTestNet));
+    obj.push_back(Pair("testnet",          TestNet()));
     return obj;
 }
 
diff --git a/src/rpcnet.cpp b/src/rpcnet.cpp
index 644c2675ae..bd7bc0ba10 100644
--- a/src/rpcnet.cpp
+++ b/src/rpcnet.cpp
@@ -157,7 +157,7 @@ Value getaddednodeinfo(const Array& params, bool fHelp)
     BOOST_FOREACH(string& strAddNode, laddedNodes)
     {
         vector<CService> vservNode(0);
-        if(Lookup(strAddNode.c_str(), vservNode, GetDefaultPort(), fNameLookup, 0))
+        if(Lookup(strAddNode.c_str(), vservNode, Params().GetDefaultPort(), fNameLookup, 0))
             laddedAddreses.push_back(make_pair(strAddNode, vservNode));
         else
         {
diff --git a/src/rpcwallet.cpp b/src/rpcwallet.cpp
index 585bdb2bfb..5388bd4d84 100644
--- a/src/rpcwallet.cpp
+++ b/src/rpcwallet.cpp
@@ -79,7 +79,7 @@ Value getinfo(const Array& params, bool fHelp)
     obj.push_back(Pair("connections",   (int)vNodes.size()));
     obj.push_back(Pair("proxy",         (proxy.first.IsValid() ? proxy.first.ToStringIPPort() : string())));
     obj.push_back(Pair("difficulty",    (double)GetDifficulty()));
-    obj.push_back(Pair("testnet",       fTestNet));
+    obj.push_back(Pair("testnet",       TestNet()));
     obj.push_back(Pair("keypoololdest", (boost::int64_t)pwalletMain->GetOldestKeyPoolTime()));
     obj.push_back(Pair("keypoolsize",   pwalletMain->GetKeyPoolSize()));
     obj.push_back(Pair("paytxfee",      ValueFromAmount(nTransactionFee)));
diff --git a/src/test/DoS_tests.cpp b/src/test/DoS_tests.cpp
index b1e98f65ed..ea0cc1bcef 100644
--- a/src/test/DoS_tests.cpp
+++ b/src/test/DoS_tests.cpp
@@ -8,6 +8,7 @@
 #include <boost/test/unit_test.hpp>
 #include <boost/foreach.hpp>
 
+#include "chainparams.h"
 #include "main.h"
 #include "wallet.h"
 #include "net.h"
@@ -25,7 +26,7 @@ CService ip(uint32_t i)
 {
     struct in_addr s;
     s.s_addr = i;
-    return CService(CNetAddr(s), GetDefaultPort());
+    return CService(CNetAddr(s), Params().GetDefaultPort());
 }
 
 BOOST_AUTO_TEST_SUITE(DoS_tests)
diff --git a/src/test/base58_tests.cpp b/src/test/base58_tests.cpp
index 2741672a88..af65416485 100644
--- a/src/test/base58_tests.cpp
+++ b/src/test/base58_tests.cpp
@@ -108,8 +108,6 @@ BOOST_AUTO_TEST_CASE(base58_keys_valid_parse)
     std::vector<unsigned char> result;
     CBitcoinSecret secret;
     CBitcoinAddress addr;
-    // Save global state
-    bool fTestNet_stored = fTestNet;
 
     BOOST_FOREACH(Value& tv, tests)
     {
@@ -125,7 +123,10 @@ BOOST_AUTO_TEST_CASE(base58_keys_valid_parse)
         const Object &metadata = test[2].get_obj();
         bool isPrivkey = find_value(metadata, "isPrivkey").get_bool();
         bool isTestnet = find_value(metadata, "isTestnet").get_bool();
-        fTestNet = isTestnet; // Override testnet flag
+        if (isTestnet)
+            SelectParams(CChainParams::TESTNET);
+        else
+            SelectParams(CChainParams::MAIN);
         if(isPrivkey)
         {
             bool isCompressed = find_value(metadata, "isCompressed").get_bool();
@@ -156,8 +157,7 @@ BOOST_AUTO_TEST_CASE(base58_keys_valid_parse)
             BOOST_CHECK_MESSAGE(!secret.IsValid(), "IsValid pubkey as privkey:" + strTest);
         }
     }
-    // Restore global state
-    fTestNet = fTestNet_stored;
+    SelectParams(CChainParams::MAIN);
 }
 
 // Goal: check that generated keys match test vectors
@@ -165,9 +165,6 @@ BOOST_AUTO_TEST_CASE(base58_keys_valid_gen)
 {
     Array tests = read_json("base58_keys_valid.json");
     std::vector<unsigned char> result;
-    // Save global state
-    bool fTestNet_stored = fTestNet;
-
     BOOST_FOREACH(Value& tv, tests)
     {
         Array test = tv.get_array();
@@ -182,7 +179,10 @@ BOOST_AUTO_TEST_CASE(base58_keys_valid_gen)
         const Object &metadata = test[2].get_obj();
         bool isPrivkey = find_value(metadata, "isPrivkey").get_bool();
         bool isTestnet = find_value(metadata, "isTestnet").get_bool();
-        fTestNet = isTestnet; // Override testnet flag
+        if (isTestnet)
+            SelectParams(CChainParams::TESTNET);
+        else
+            SelectParams(CChainParams::MAIN);
         if(isPrivkey)
         {
             bool isCompressed = find_value(metadata, "isCompressed").get_bool();
@@ -225,8 +225,7 @@ BOOST_AUTO_TEST_CASE(base58_keys_valid_gen)
     CTxDestination nodest = CNoDestination();
     BOOST_CHECK(!boost::apply_visitor(CBitcoinAddressVisitor(&dummyAddr), nodest));
 
-    // Restore global state
-    fTestNet = fTestNet_stored;
+    SelectParams(CChainParams::MAIN);
 }
 
 // Goal: check that base58 parsing code is robust against a variety of corrupted data
diff --git a/src/txdb.cpp b/src/txdb.cpp
index 3d34710d22..34836eaa97 100644
--- a/src/txdb.cpp
+++ b/src/txdb.cpp
@@ -6,6 +6,7 @@
 #include "txdb.h"
 #include "main.h"
 #include "hash.h"
+#include "chainparams.h"
 
 using namespace std;
 
@@ -223,7 +224,7 @@ bool CBlockTreeDB::LoadBlockIndexGuts()
                 pindexNew->nTx            = diskindex.nTx;
 
                 // Watch for genesis block
-                if (pindexGenesisBlock == NULL && diskindex.GetBlockHash() == hashGenesisBlock)
+                if (pindexGenesisBlock == NULL && diskindex.GetBlockHash() == Params().HashGenesisBlock())
                     pindexGenesisBlock = pindexNew;
 
                 if (!pindexNew->CheckIndex())
diff --git a/src/util.cpp b/src/util.cpp
index f4892a2387..bfb6d75838 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -13,6 +13,7 @@
 #include <sys/resource.h>
 #endif
 
+#include "chainparams.h"
 #include "util.h"
 #include "sync.h"
 #include "version.h"
@@ -78,7 +79,6 @@ bool fDaemon = false;
 bool fServer = false;
 bool fCommandLine = false;
 string strMiscWarning;
-bool fTestNet = false;
 bool fNoListen = false;
 bool fLogTimestamps = false;
 CMedianFilter<int64> vTimeOffsets(200,0);
@@ -1068,8 +1068,8 @@ const boost::filesystem::path &GetDataDir(bool fNetSpecific)
     } else {
         path = GetDefaultDataDir();
     }
-    if (fNetSpecific && GetBoolArg("-testnet", false))
-        path /= "testnet3";
+    if (fNetSpecific)
+        path /= Params().DataDir();
 
     fs::create_directories(path);
 
diff --git a/src/util.h b/src/util.h
index 9173b5bb58..86a38ad331 100644
--- a/src/util.h
+++ b/src/util.h
@@ -143,7 +143,6 @@ extern bool fDaemon;
 extern bool fServer;
 extern bool fCommandLine;
 extern std::string strMiscWarning;
-extern bool fTestNet;
 extern bool fNoListen;
 extern bool fLogTimestamps;
 extern volatile bool fReopenDebugLog;