Merge branch 'master' of github.com:bitcoin/bitcoin

1 files changed, 1206 insertions, 0 deletions

diff --git a/src/script.cpp b/src/script.cpp
new file mode 100644
index 0000000000..a85c3710a3
--- /dev/null
+++ b/src/script.cpp
@@ -0,0 +1,1206 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Distributed under the MIT/X11 software license, see the accompanying
+// file license.txt or http://www.opensource.org/licenses/mit-license.php.
+
+#include "headers.h"
+
+bool CheckSig(vector<unsigned char> vchSig, vector<unsigned char> vchPubKey, CScript scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType);
+
+
+
+typedef vector<unsigned char> valtype;
+static const valtype vchFalse(0);
+static const valtype vchZero(0);
+static const valtype vchTrue(1, 1);
+static const CBigNum bnZero(0);
+static const CBigNum bnOne(1);
+static const CBigNum bnFalse(0);
+static const CBigNum bnTrue(1);
+static const size_t nMaxNumSize = 4;
+
+
+CBigNum CastToBigNum(const valtype& vch)
+{
+    if (vch.size() > nMaxNumSize)
+        throw runtime_error("CastToBigNum() : overflow");
+    // Get rid of extra leading zeros
+    return CBigNum(CBigNum(vch).getvch());
+}
+
+bool CastToBool(const valtype& vch)
+{
+    for (int i = 0; i < vch.size(); i++)
+    {
+        if (vch[i] != 0)
+        {
+            // Can be negative zero
+            if (i == vch.size()-1 && vch[i] == 0x80)
+                return false;
+            return true;
+        }
+    }
+    return false;
+}
+
+void MakeSameSize(valtype& vch1, valtype& vch2)
+{
+    // Lengthen the shorter one
+    if (vch1.size() < vch2.size())
+        vch1.resize(vch2.size(), 0);
+    if (vch2.size() < vch1.size())
+        vch2.resize(vch1.size(), 0);
+}
+
+
+
+//
+// Script is a stack machine (like Forth) that evaluates a predicate
+// returning a bool indicating valid or not.  There are no loops.
+//
+#define stacktop(i)  (stack.at(stack.size()+(i)))
+#define altstacktop(i)  (altstack.at(altstack.size()+(i)))
+static inline void popstack(vector<valtype>& stack)
+{
+    if (stack.empty())
+        throw runtime_error("popstack() : stack empty");
+    stack.pop_back();
+}
+
+
+bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, const CTransaction& txTo, unsigned int nIn, int nHashType)
+{
+    CAutoBN_CTX pctx;
+    CScript::const_iterator pc = script.begin();
+    CScript::const_iterator pend = script.end();
+    CScript::const_iterator pbegincodehash = script.begin();
+    opcodetype opcode;
+    valtype vchPushValue;
+    vector<bool> vfExec;
+    vector<valtype> altstack;
+    if (script.size() > 10000)
+        return false;
+    int nOpCount = 0;
+
+
+    try
+    {
+        while (pc < pend)
+        {
+            bool fExec = !count(vfExec.begin(), vfExec.end(), false);
+
+            //
+            // Read instruction
+            //
+            if (!script.GetOp(pc, opcode, vchPushValue))
+                return false;
+            if (vchPushValue.size() > 520)
+                return false;
+            if (opcode > OP_16 && ++nOpCount > 201)
+                return false;
+
+            if (opcode == OP_CAT ||
+                opcode == OP_SUBSTR ||
+                opcode == OP_LEFT ||
+                opcode == OP_RIGHT ||
+                opcode == OP_INVERT ||
+                opcode == OP_AND ||
+                opcode == OP_OR ||
+                opcode == OP_XOR ||
+                opcode == OP_2MUL ||
+                opcode == OP_2DIV ||
+                opcode == OP_MUL ||
+                opcode == OP_DIV ||
+                opcode == OP_MOD ||
+                opcode == OP_LSHIFT ||
+                opcode == OP_RSHIFT)
+                return false;
+
+            if (fExec && 0 <= opcode && opcode <= OP_PUSHDATA4)
+                stack.push_back(vchPushValue);
+            else if (fExec || (OP_IF <= opcode && opcode <= OP_ENDIF))
+            switch (opcode)
+            {
+                //
+                // Push value
+                //
+                case OP_1NEGATE:
+                case OP_1:
+                case OP_2:
+                case OP_3:
+                case OP_4:
+                case OP_5:
+                case OP_6:
+                case OP_7:
+                case OP_8:
+                case OP_9:
+                case OP_10:
+                case OP_11:
+                case OP_12:
+                case OP_13:
+                case OP_14:
+                case OP_15:
+                case OP_16:
+                {
+                    // ( -- value)
+                    CBigNum bn((int)opcode - (int)(OP_1 - 1));
+                    stack.push_back(bn.getvch());
+                }
+                break;
+
+
+                //
+                // Control
+                //
+                case OP_NOP:
+                case OP_NOP1: case OP_NOP2: case OP_NOP3: case OP_NOP4: case OP_NOP5:
+                case OP_NOP6: case OP_NOP7: case OP_NOP8: case OP_NOP9: case OP_NOP10:
+                break;
+
+                case OP_IF:
+                case OP_NOTIF:
+                {
+                    // <expression> if [statements] [else [statements]] endif
+                    bool fValue = false;
+                    if (fExec)
+                    {
+                        if (stack.size() < 1)
+                            return false;
+                        valtype& vch = stacktop(-1);
+                        fValue = CastToBool(vch);
+                        if (opcode == OP_NOTIF)
+                            fValue = !fValue;
+                        popstack(stack);
+                    }
+                    vfExec.push_back(fValue);
+                }
+                break;
+
+                case OP_ELSE:
+                {
+                    if (vfExec.empty())
+                        return false;
+                    vfExec.back() = !vfExec.back();
+                }
+                break;
+
+                case OP_ENDIF:
+                {
+                    if (vfExec.empty())
+                        return false;
+                    vfExec.pop_back();
+                }
+                break;
+
+                case OP_VERIFY:
+                {
+                    // (true -- ) or
+                    // (false -- false) and return
+                    if (stack.size() < 1)
+                        return false;
+                    bool fValue = CastToBool(stacktop(-1));
+                    if (fValue)
+                        popstack(stack);
+                    else
+                        return false;
+                }
+                break;
+
+                case OP_RETURN:
+                {
+                    return false;
+                }
+                break;
+
+
+                //
+                // Stack ops
+                //
+                case OP_TOALTSTACK:
+                {
+                    if (stack.size() < 1)
+                        return false;
+                    altstack.push_back(stacktop(-1));
+                    popstack(stack);
+                }
+                break;
+
+                case OP_FROMALTSTACK:
+                {
+                    if (altstack.size() < 1)
+                        return false;
+                    stack.push_back(altstacktop(-1));
+                    popstack(altstack);
+                }
+                break;
+
+                case OP_2DROP:
+                {
+                    // (x1 x2 -- )
+                    if (stack.size() < 2)
+                        return false;
+                    popstack(stack);
+                    popstack(stack);
+                }
+                break;
+
+                case OP_2DUP:
+                {
+                    // (x1 x2 -- x1 x2 x1 x2)
+                    if (stack.size() < 2)
+                        return false;
+                    valtype vch1 = stacktop(-2);
+                    valtype vch2 = stacktop(-1);
+                    stack.push_back(vch1);
+                    stack.push_back(vch2);
+                }
+                break;
+
+                case OP_3DUP:
+                {
+                    // (x1 x2 x3 -- x1 x2 x3 x1 x2 x3)
+                    if (stack.size() < 3)
+                        return false;
+                    valtype vch1 = stacktop(-3);
+                    valtype vch2 = stacktop(-2);
+                    valtype vch3 = stacktop(-1);
+                    stack.push_back(vch1);
+                    stack.push_back(vch2);
+                    stack.push_back(vch3);
+                }
+                break;
+
+                case OP_2OVER:
+                {
+                    // (x1 x2 x3 x4 -- x1 x2 x3 x4 x1 x2)
+                    if (stack.size() < 4)
+                        return false;
+                    valtype vch1 = stacktop(-4);
+                    valtype vch2 = stacktop(-3);
+                    stack.push_back(vch1);
+                    stack.push_back(vch2);
+                }
+                break;
+
+                case OP_2ROT:
+                {
+                    // (x1 x2 x3 x4 x5 x6 -- x3 x4 x5 x6 x1 x2)
+                    if (stack.size() < 6)
+                        return false;
+                    valtype vch1 = stacktop(-6);
+                    valtype vch2 = stacktop(-5);
+                    stack.erase(stack.end()-6, stack.end()-4);
+                    stack.push_back(vch1);
+                    stack.push_back(vch2);
+                }
+                break;
+
+                case OP_2SWAP:
+                {
+                    // (x1 x2 x3 x4 -- x3 x4 x1 x2)
+                    if (stack.size() < 4)
+                        return false;
+                    swap(stacktop(-4), stacktop(-2));
+                    swap(stacktop(-3), stacktop(-1));
+                }
+                break;
+
+                case OP_IFDUP:
+                {
+                    // (x - 0 | x x)
+                    if (stack.size() < 1)
+                        return false;
+                    valtype vch = stacktop(-1);
+                    if (CastToBool(vch))
+                        stack.push_back(vch);
+                }
+                break;
+
+                case OP_DEPTH:
+                {
+                    // -- stacksize
+                    CBigNum bn(stack.size());
+                    stack.push_back(bn.getvch());
+                }
+                break;
+
+                case OP_DROP:
+                {
+                    // (x -- )
+                    if (stack.size() < 1)
+                        return false;
+                    popstack(stack);
+                }
+                break;
+
+                case OP_DUP:
+                {
+                    // (x -- x x)
+                    if (stack.size() < 1)
+                        return false;
+                    valtype vch = stacktop(-1);
+                    stack.push_back(vch);
+                }
+                break;
+
+                case OP_NIP:
+                {
+                    // (x1 x2 -- x2)
+                    if (stack.size() < 2)
+                        return false;
+                    stack.erase(stack.end() - 2);
+                }
+                break;
+
+                case OP_OVER:
+                {
+                    // (x1 x2 -- x1 x2 x1)
+                    if (stack.size() < 2)
+                        return false;
+                    valtype vch = stacktop(-2);
+                    stack.push_back(vch);
+                }
+                break;
+
+                case OP_PICK:
+                case OP_ROLL:
+                {
+                    // (xn ... x2 x1 x0 n - xn ... x2 x1 x0 xn)
+                    // (xn ... x2 x1 x0 n - ... x2 x1 x0 xn)
+                    if (stack.size() < 2)
+                        return false;
+                    int n = CastToBigNum(stacktop(-1)).getint();
+                    popstack(stack);
+                    if (n < 0 || n >= stack.size())
+                        return false;
+                    valtype vch = stacktop(-n-1);
+                    if (opcode == OP_ROLL)
+                        stack.erase(stack.end()-n-1);
+                    stack.push_back(vch);
+                }
+                break;
+
+                case OP_ROT:
+                {
+                    // (x1 x2 x3 -- x2 x3 x1)
+                    //  x2 x1 x3  after first swap
+                    //  x2 x3 x1  after second swap
+                    if (stack.size() < 3)
+                        return false;
+                    swap(stacktop(-3), stacktop(-2));
+                    swap(stacktop(-2), stacktop(-1));
+                }
+                break;
+
+                case OP_SWAP:
+                {
+                    // (x1 x2 -- x2 x1)
+                    if (stack.size() < 2)
+                        return false;
+                    swap(stacktop(-2), stacktop(-1));
+                }
+                break;
+
+                case OP_TUCK:
+                {
+                    // (x1 x2 -- x2 x1 x2)
+                    if (stack.size() < 2)
+                        return false;
+                    valtype vch = stacktop(-1);
+                    stack.insert(stack.end()-2, vch);
+                }
+                break;
+
+
+                //
+                // Splice ops
+                //
+                case OP_CAT:
+                {
+                    // (x1 x2 -- out)
+                    if (stack.size() < 2)
+                        return false;
+                    valtype& vch1 = stacktop(-2);
+                    valtype& vch2 = stacktop(-1);
+                    vch1.insert(vch1.end(), vch2.begin(), vch2.end());
+                    popstack(stack);
+                    if (stacktop(-1).size() > 520)
+                        return false;
+                }
+                break;
+
+                case OP_SUBSTR:
+                {
+                    // (in begin size -- out)
+                    if (stack.size() < 3)
+                        return false;
+                    valtype& vch = stacktop(-3);
+                    int nBegin = CastToBigNum(stacktop(-2)).getint();
+                    int nEnd = nBegin + CastToBigNum(stacktop(-1)).getint();
+                    if (nBegin < 0 || nEnd < nBegin)
+                        return false;
+                    if (nBegin > vch.size())
+                        nBegin = vch.size();
+                    if (nEnd > vch.size())
+                        nEnd = vch.size();
+                    vch.erase(vch.begin() + nEnd, vch.end());
+                    vch.erase(vch.begin(), vch.begin() + nBegin);
+                    popstack(stack);
+                    popstack(stack);
+                }
+                break;
+
+                case OP_LEFT:
+                case OP_RIGHT:
+                {
+                    // (in size -- out)
+                    if (stack.size() < 2)
+                        return false;
+                    valtype& vch = stacktop(-2);
+                    int nSize = CastToBigNum(stacktop(-1)).getint();
+                    if (nSize < 0)
+                        return false;
+                    if (nSize > vch.size())
+                        nSize = vch.size();
+                    if (opcode == OP_LEFT)
+                        vch.erase(vch.begin() + nSize, vch.end());
+                    else
+                        vch.erase(vch.begin(), vch.end() - nSize);
+                    popstack(stack);
+                }
+                break;
+
+                case OP_SIZE:
+                {
+                    // (in -- in size)
+                    if (stack.size() < 1)
+                        return false;
+                    CBigNum bn(stacktop(-1).size());
+                    stack.push_back(bn.getvch());
+                }
+                break;
+
+
+                //
+                // Bitwise logic
+                //
+                case OP_INVERT:
+                {
+                    // (in - out)
+                    if (stack.size() < 1)
+                        return false;
+                    valtype& vch = stacktop(-1);
+                    for (int i = 0; i < vch.size(); i++)
+                        vch[i] = ~vch[i];
+                }
+                break;
+
+                case OP_AND:
+                case OP_OR:
+                case OP_XOR:
+                {
+                    // (x1 x2 - out)
+                    if (stack.size() < 2)
+                        return false;
+                    valtype& vch1 = stacktop(-2);
+                    valtype& vch2 = stacktop(-1);
+                    MakeSameSize(vch1, vch2);
+                    if (opcode == OP_AND)
+                    {
+                        for (int i = 0; i < vch1.size(); i++)
+                            vch1[i] &= vch2[i];
+                    }
+                    else if (opcode == OP_OR)
+                    {
+                        for (int i = 0; i < vch1.size(); i++)
+                            vch1[i] |= vch2[i];
+                    }
+                    else if (opcode == OP_XOR)
+                    {
+                        for (int i = 0; i < vch1.size(); i++)
+                            vch1[i] ^= vch2[i];
+                    }
+                    popstack(stack);
+                }
+                break;
+
+                case OP_EQUAL:
+                case OP_EQUALVERIFY:
+                //case OP_NOTEQUAL: // use OP_NUMNOTEQUAL
+                {
+                    // (x1 x2 - bool)
+                    if (stack.size() < 2)
+                        return false;
+                    valtype& vch1 = stacktop(-2);
+                    valtype& vch2 = stacktop(-1);
+                    bool fEqual = (vch1 == vch2);
+                    // OP_NOTEQUAL is disabled because it would be too easy to say
+                    // something like n != 1 and have some wiseguy pass in 1 with extra
+                    // zero bytes after it (numerically, 0x01 == 0x0001 == 0x000001)
+                    //if (opcode == OP_NOTEQUAL)
+                    //    fEqual = !fEqual;
+                    popstack(stack);
+                    popstack(stack);
+                    stack.push_back(fEqual ? vchTrue : vchFalse);
+                    if (opcode == OP_EQUALVERIFY)
+                    {
+                        if (fEqual)
+                            popstack(stack);
+                        else
+                            return false;
+                    }
+                }
+                break;
+
+
+                //
+                // Numeric
+                //
+                case OP_1ADD:
+                case OP_1SUB:
+                case OP_2MUL:
+                case OP_2DIV:
+                case OP_NEGATE:
+                case OP_ABS:
+                case OP_NOT:
+                case OP_0NOTEQUAL:
+                {
+                    // (in -- out)
+                    if (stack.size() < 1)
+                        return false;
+                    CBigNum bn = CastToBigNum(stacktop(-1));
+                    switch (opcode)
+                    {
+                    case OP_1ADD:       bn += bnOne; break;
+                    case OP_1SUB:       bn -= bnOne; break;
+                    case OP_2MUL:       bn <<= 1; break;
+                    case OP_2DIV:       bn >>= 1; break;
+                    case OP_NEGATE:     bn = -bn; break;
+                    case OP_ABS:        if (bn < bnZero) bn = -bn; break;
+                    case OP_NOT:        bn = (bn == bnZero); break;
+                    case OP_0NOTEQUAL:  bn = (bn != bnZero); break;
+                    }
+                    popstack(stack);
+                    stack.push_back(bn.getvch());
+                }
+                break;
+
+                case OP_ADD:
+                case OP_SUB:
+                case OP_MUL:
+                case OP_DIV:
+                case OP_MOD:
+                case OP_LSHIFT:
+                case OP_RSHIFT:
+                case OP_BOOLAND:
+                case OP_BOOLOR:
+                case OP_NUMEQUAL:
+                case OP_NUMEQUALVERIFY:
+                case OP_NUMNOTEQUAL:
+                case OP_LESSTHAN:
+                case OP_GREATERTHAN:
+                case OP_LESSTHANOREQUAL:
+                case OP_GREATERTHANOREQUAL:
+                case OP_MIN:
+                case OP_MAX:
+                {
+                    // (x1 x2 -- out)
+                    if (stack.size() < 2)
+                        return false;
+                    CBigNum bn1 = CastToBigNum(stacktop(-2));
+                    CBigNum bn2 = CastToBigNum(stacktop(-1));
+                    CBigNum bn;
+                    switch (opcode)
+                    {
+                    case OP_ADD:
+                        bn = bn1 + bn2;
+                        break;
+
+                    case OP_SUB:
+                        bn = bn1 - bn2;
+                        break;
+
+                    case OP_MUL:
+                        if (!BN_mul(&bn, &bn1, &bn2, pctx))
+                            return false;
+                        break;
+
+                    case OP_DIV:
+                        if (!BN_div(&bn, NULL, &bn1, &bn2, pctx))
+                            return false;
+                        break;
+
+                    case OP_MOD:
+                        if (!BN_mod(&bn, &bn1, &bn2, pctx))
+                            return false;
+                        break;
+
+                    case OP_LSHIFT:
+                        if (bn2 < bnZero || bn2 > CBigNum(2048))
+                            return false;
+                        bn = bn1 << bn2.getulong();
+                        break;
+
+                    case OP_RSHIFT:
+                        if (bn2 < bnZero || bn2 > CBigNum(2048))
+                            return false;
+                        bn = bn1 >> bn2.getulong();
+                        break;
+
+                    case OP_BOOLAND:             bn = (bn1 != bnZero && bn2 != bnZero); break;
+                    case OP_BOOLOR:              bn = (bn1 != bnZero || bn2 != bnZero); break;
+                    case OP_NUMEQUAL:            bn = (bn1 == bn2); break;
+                    case OP_NUMEQUALVERIFY:      bn = (bn1 == bn2); break;
+                    case OP_NUMNOTEQUAL:         bn = (bn1 != bn2); break;
+                    case OP_LESSTHAN:            bn = (bn1 < bn2); break;
+                    case OP_GREATERTHAN:         bn = (bn1 > bn2); break;
+                    case OP_LESSTHANOREQUAL:     bn = (bn1 <= bn2); break;
+                    case OP_GREATERTHANOREQUAL:  bn = (bn1 >= bn2); break;
+                    case OP_MIN:                 bn = (bn1 < bn2 ? bn1 : bn2); break;
+                    case OP_MAX:                 bn = (bn1 > bn2 ? bn1 : bn2); break;
+                    }
+                    popstack(stack);
+                    popstack(stack);
+                    stack.push_back(bn.getvch());
+
+                    if (opcode == OP_NUMEQUALVERIFY)
+                    {
+                        if (CastToBool(stacktop(-1)))
+                            popstack(stack);
+                        else
+                            return false;
+                    }
+                }
+                break;
+
+                case OP_WITHIN:
+                {
+                    // (x min max -- out)
+                    if (stack.size() < 3)
+                        return false;
+                    CBigNum bn1 = CastToBigNum(stacktop(-3));
+                    CBigNum bn2 = CastToBigNum(stacktop(-2));
+                    CBigNum bn3 = CastToBigNum(stacktop(-1));
+                    bool fValue = (bn2 <= bn1 && bn1 < bn3);
+                    popstack(stack);
+                    popstack(stack);
+                    popstack(stack);
+                    stack.push_back(fValue ? vchTrue : vchFalse);
+                }
+                break;
+
+
+                //
+                // Crypto
+                //
+                case OP_RIPEMD160:
+                case OP_SHA1:
+                case OP_SHA256:
+                case OP_HASH160:
+                case OP_HASH256:
+                {
+                    // (in -- hash)
+                    if (stack.size() < 1)
+                        return false;
+                    valtype& vch = stacktop(-1);
+                    valtype vchHash((opcode == OP_RIPEMD160 || opcode == OP_SHA1 || opcode == OP_HASH160) ? 20 : 32);
+                    if (opcode == OP_RIPEMD160)
+                        RIPEMD160(&vch[0], vch.size(), &vchHash[0]);
+                    else if (opcode == OP_SHA1)
+                        SHA1(&vch[0], vch.size(), &vchHash[0]);
+                    else if (opcode == OP_SHA256)
+                        SHA256(&vch[0], vch.size(), &vchHash[0]);
+                    else if (opcode == OP_HASH160)
+                    {
+                        uint160 hash160 = Hash160(vch);
+                        memcpy(&vchHash[0], &hash160, sizeof(hash160));
+                    }
+                    else if (opcode == OP_HASH256)
+                    {
+                        uint256 hash = Hash(vch.begin(), vch.end());
+                        memcpy(&vchHash[0], &hash, sizeof(hash));
+                    }
+                    popstack(stack);
+                    stack.push_back(vchHash);
+                }
+                break;
+
+                case OP_CODESEPARATOR:
+                {
+                    // Hash starts after the code separator
+                    pbegincodehash = pc;
+                }
+                break;
+
+                case OP_CHECKSIG:
+                case OP_CHECKSIGVERIFY:
+                {
+                    // (sig pubkey -- bool)
+                    if (stack.size() < 2)
+                        return false;
+
+                    valtype& vchSig    = stacktop(-2);
+                    valtype& vchPubKey = stacktop(-1);
+
+                    ////// debug print
+                    //PrintHex(vchSig.begin(), vchSig.end(), "sig: %s\n");
+                    //PrintHex(vchPubKey.begin(), vchPubKey.end(), "pubkey: %s\n");
+
+                    // Subset of script starting at the most recent codeseparator
+                    CScript scriptCode(pbegincodehash, pend);
+
+                    // Drop the signature, since there's no way for a signature to sign itself
+                    scriptCode.FindAndDelete(CScript(vchSig));
+
+                    bool fSuccess = CheckSig(vchSig, vchPubKey, scriptCode, txTo, nIn, nHashType);
+
+                    popstack(stack);
+                    popstack(stack);
+                    stack.push_back(fSuccess ? vchTrue : vchFalse);
+                    if (opcode == OP_CHECKSIGVERIFY)
+                    {
+                        if (fSuccess)
+                            popstack(stack);
+                        else
+                            return false;
+                    }
+                }
+                break;
+
+                case OP_CHECKMULTISIG:
+                case OP_CHECKMULTISIGVERIFY:
+                {
+                    // ([sig ...] num_of_signatures [pubkey ...] num_of_pubkeys -- bool)
+
+                    int i = 1;
+                    if (stack.size() < i)
+                        return false;
+
+                    int nKeysCount = CastToBigNum(stacktop(-i)).getint();
+                    if (nKeysCount < 0 || nKeysCount > 20)
+                        return false;
+                    nOpCount += nKeysCount;
+                    if (nOpCount > 201)
+                        return false;
+                    int ikey = ++i;
+                    i += nKeysCount;
+                    if (stack.size() < i)
+                        return false;
+
+                    int nSigsCount = CastToBigNum(stacktop(-i)).getint();
+                    if (nSigsCount < 0 || nSigsCount > nKeysCount)
+                        return false;
+                    int isig = ++i;
+                    i += nSigsCount;
+                    if (stack.size() < i)
+                        return false;
+
+                    // Subset of script starting at the most recent codeseparator
+                    CScript scriptCode(pbegincodehash, pend);
+
+                    // Drop the signatures, since there's no way for a signature to sign itself
+                    for (int k = 0; k < nSigsCount; k++)
+                    {
+                        valtype& vchSig = stacktop(-isig-k);
+                        scriptCode.FindAndDelete(CScript(vchSig));
+                    }
+
+                    bool fSuccess = true;
+                    while (fSuccess && nSigsCount > 0)
+                    {
+                        valtype& vchSig    = stacktop(-isig);
+                        valtype& vchPubKey = stacktop(-ikey);
+
+                        // Check signature
+                        if (CheckSig(vchSig, vchPubKey, scriptCode, txTo, nIn, nHashType))
+                        {
+                            isig++;
+                            nSigsCount--;
+                        }
+                        ikey++;
+                        nKeysCount--;
+
+                        // If there are more signatures left than keys left,
+                        // then too many signatures have failed
+                        if (nSigsCount > nKeysCount)
+                            fSuccess = false;
+                    }
+
+                    while (i-- > 0)
+                        popstack(stack);
+                    stack.push_back(fSuccess ? vchTrue : vchFalse);
+
+                    if (opcode == OP_CHECKMULTISIGVERIFY)
+                    {
+                        if (fSuccess)
+                            popstack(stack);
+                        else
+                            return false;
+                    }
+                }
+                break;
+
+                default:
+                    return false;
+            }
+
+            // Size limits
+            if (stack.size() + altstack.size() > 1000)
+                return false;
+        }
+    }
+    catch (...)
+    {
+        return false;
+    }
+
+
+    if (!vfExec.empty())
+        return false;
+
+    return true;
+}
+
+
+
+
+
+
+
+
+
+uint256 SignatureHash(CScript scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType)
+{
+    if (nIn >= txTo.vin.size())
+    {
+        printf("ERROR: SignatureHash() : nIn=%d out of range\n", nIn);
+        return 1;
+    }
+    CTransaction txTmp(txTo);
+
+    // In case concatenating two scripts ends up with two codeseparators,
+    // or an extra one at the end, this prevents all those possible incompatibilities.
+    scriptCode.FindAndDelete(CScript(OP_CODESEPARATOR));
+
+    // Blank out other inputs' signatures
+    for (int i = 0; i < txTmp.vin.size(); i++)
+        txTmp.vin[i].scriptSig = CScript();
+    txTmp.vin[nIn].scriptSig = scriptCode;
+
+    // Blank out some of the outputs
+    if ((nHashType & 0x1f) == SIGHASH_NONE)
+    {
+        // Wildcard payee
+        txTmp.vout.clear();
+
+        // Let the others update at will
+        for (int i = 0; i < txTmp.vin.size(); i++)
+            if (i != nIn)
+                txTmp.vin[i].nSequence = 0;
+    }
+    else if ((nHashType & 0x1f) == SIGHASH_SINGLE)
+    {
+        // Only lockin the txout payee at same index as txin
+        unsigned int nOut = nIn;
+        if (nOut >= txTmp.vout.size())
+        {
+            printf("ERROR: SignatureHash() : nOut=%d out of range\n", nOut);
+            return 1;
+        }
+        txTmp.vout.resize(nOut+1);
+        for (int i = 0; i < nOut; i++)
+            txTmp.vout[i].SetNull();
+
+        // Let the others update at will
+        for (int i = 0; i < txTmp.vin.size(); i++)
+            if (i != nIn)
+                txTmp.vin[i].nSequence = 0;
+    }
+
+    // Blank out other inputs completely, not recommended for open transactions
+    if (nHashType & SIGHASH_ANYONECANPAY)
+    {
+        txTmp.vin[0] = txTmp.vin[nIn];
+        txTmp.vin.resize(1);
+    }
+
+    // Serialize and hash
+    CDataStream ss(SER_GETHASH);
+    ss.reserve(10000);
+    ss << txTmp << nHashType;
+    return Hash(ss.begin(), ss.end());
+}
+
+
+bool CheckSig(vector<unsigned char> vchSig, vector<unsigned char> vchPubKey, CScript scriptCode,
+              const CTransaction& txTo, unsigned int nIn, int nHashType)
+{
+    CKey key;
+    if (!key.SetPubKey(vchPubKey))
+        return false;
+
+    // Hash type is one byte tacked on to the end of the signature
+    if (vchSig.empty())
+        return false;
+    if (nHashType == 0)
+        nHashType = vchSig.back();
+    else if (nHashType != vchSig.back())
+        return false;
+    vchSig.pop_back();
+
+    return key.Verify(SignatureHash(scriptCode, txTo, nIn, nHashType), vchSig);
+}
+
+
+
+
+
+
+
+
+
+
+bool Solver(const CScript& scriptPubKey, vector<pair<opcodetype, valtype> >& vSolutionRet)
+{
+    // Templates
+    static vector<CScript> vTemplates;
+    if (vTemplates.empty())
+    {
+        // Standard tx, sender provides pubkey, receiver adds signature
+        vTemplates.push_back(CScript() << OP_PUBKEY << OP_CHECKSIG);
+
+        // Bitcoin address tx, sender provides hash of pubkey, receiver provides signature and pubkey
+        vTemplates.push_back(CScript() << OP_DUP << OP_HASH160 << OP_PUBKEYHASH << OP_EQUALVERIFY << OP_CHECKSIG);
+    }
+
+    // Scan templates
+    const CScript& script1 = scriptPubKey;
+    foreach(const CScript& script2, vTemplates)
+    {
+        vSolutionRet.clear();
+        opcodetype opcode1, opcode2;
+        vector<unsigned char> vch1, vch2;
+
+        // Compare
+        CScript::const_iterator pc1 = script1.begin();
+        CScript::const_iterator pc2 = script2.begin();
+        loop
+        {
+            if (pc1 == script1.end() && pc2 == script2.end())
+            {
+                // Found a match
+                reverse(vSolutionRet.begin(), vSolutionRet.end());
+                return true;
+            }
+            if (!script1.GetOp(pc1, opcode1, vch1))
+                break;
+            if (!script2.GetOp(pc2, opcode2, vch2))
+                break;
+            if (opcode2 == OP_PUBKEY)
+            {
+                if (vch1.size() < 33 || vch1.size() > 120)
+                    break;
+                vSolutionRet.push_back(make_pair(opcode2, vch1));
+            }
+            else if (opcode2 == OP_PUBKEYHASH)
+            {
+                if (vch1.size() != sizeof(uint160))
+                    break;
+                vSolutionRet.push_back(make_pair(opcode2, vch1));
+            }
+            else if (opcode1 != opcode2 || vch1 != vch2)
+            {
+                break;
+            }
+        }
+    }
+
+    vSolutionRet.clear();
+    return false;
+}
+
+
+bool Solver(const CScript& scriptPubKey, uint256 hash, int nHashType, CScript& scriptSigRet)
+{
+    scriptSigRet.clear();
+
+    vector<pair<opcodetype, valtype> > vSolution;
+    if (!Solver(scriptPubKey, vSolution))
+        return false;
+
+    // Compile solution
+    CRITICAL_BLOCK(cs_mapKeys)
+    {
+        foreach(PAIRTYPE(opcodetype, valtype)& item, vSolution)
+        {
+            if (item.first == OP_PUBKEY)
+            {
+                // Sign
+                const valtype& vchPubKey = item.second;
+                if (!mapKeys.count(vchPubKey))
+                    return false;
+                if (hash != 0)
+                {
+                    vector<unsigned char> vchSig;
+                    if (!CKey::Sign(mapKeys[vchPubKey], hash, vchSig))
+                        return false;
+                    vchSig.push_back((unsigned char)nHashType);
+                    scriptSigRet << vchSig;
+                }
+            }
+            else if (item.first == OP_PUBKEYHASH)
+            {
+                // Sign and give pubkey
+                map<uint160, valtype>::iterator mi = mapPubKeys.find(uint160(item.second));
+                if (mi == mapPubKeys.end())
+                    return false;
+                const vector<unsigned char>& vchPubKey = (*mi).second;
+                if (!mapKeys.count(vchPubKey))
+                    return false;
+                if (hash != 0)
+                {
+                    vector<unsigned char> vchSig;
+                    if (!CKey::Sign(mapKeys[vchPubKey], hash, vchSig))
+                        return false;
+                    vchSig.push_back((unsigned char)nHashType);
+                    scriptSigRet << vchSig << vchPubKey;
+                }
+            }
+            else
+            {
+                return false;
+            }
+        }
+    }
+
+    return true;
+}
+
+
+bool IsStandard(const CScript& scriptPubKey)
+{
+    vector<pair<opcodetype, valtype> > vSolution;
+    return Solver(scriptPubKey, vSolution);
+}
+
+
+bool IsMine(const CScript& scriptPubKey)
+{
+    CScript scriptSig;
+    return Solver(scriptPubKey, 0, 0, scriptSig);
+}
+
+
+bool ExtractPubKey(const CScript& scriptPubKey, bool fMineOnly, vector<unsigned char>& vchPubKeyRet)
+{
+    vchPubKeyRet.clear();
+
+    vector<pair<opcodetype, valtype> > vSolution;
+    if (!Solver(scriptPubKey, vSolution))
+        return false;
+
+    CRITICAL_BLOCK(cs_mapKeys)
+    {
+        foreach(PAIRTYPE(opcodetype, valtype)& item, vSolution)
+        {
+            valtype vchPubKey;
+            if (item.first == OP_PUBKEY)
+            {
+                vchPubKey = item.second;
+            }
+            else if (item.first == OP_PUBKEYHASH)
+            {
+                map<uint160, valtype>::iterator mi = mapPubKeys.find(uint160(item.second));
+                if (mi == mapPubKeys.end())
+                    continue;
+                vchPubKey = (*mi).second;
+            }
+            if (!fMineOnly || mapKeys.count(vchPubKey))
+            {
+                vchPubKeyRet = vchPubKey;
+                return true;
+            }
+        }
+    }
+    return false;
+}
+
+
+bool ExtractHash160(const CScript& scriptPubKey, uint160& hash160Ret)
+{
+    hash160Ret = 0;
+
+    vector<pair<opcodetype, valtype> > vSolution;
+    if (!Solver(scriptPubKey, vSolution))
+        return false;
+
+    foreach(PAIRTYPE(opcodetype, valtype)& item, vSolution)
+    {
+        if (item.first == OP_PUBKEYHASH)
+        {
+            hash160Ret = uint160(item.second);
+            return true;
+        }
+    }
+    return false;
+}
+
+
+bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, const CTransaction& txTo, unsigned int nIn, int nHashType)
+{
+    vector<vector<unsigned char> > stack;
+    if (!EvalScript(stack, scriptSig, txTo, nIn, nHashType))
+        return false;
+    if (!EvalScript(stack, scriptPubKey, txTo, nIn, nHashType))
+        return false;
+    if (stack.empty())
+        return false;
+    return CastToBool(stack.back());
+}
+
+
+bool SignSignature(const CTransaction& txFrom, CTransaction& txTo, unsigned int nIn, int nHashType, CScript scriptPrereq)
+{
+    assert(nIn < txTo.vin.size());
+    CTxIn& txin = txTo.vin[nIn];
+    assert(txin.prevout.n < txFrom.vout.size());
+    const CTxOut& txout = txFrom.vout[txin.prevout.n];
+
+    // Leave out the signature from the hash, since a signature can't sign itself.
+    // The checksig op will also drop the signatures from its hash.
+    uint256 hash = SignatureHash(scriptPrereq + txout.scriptPubKey, txTo, nIn, nHashType);
+
+    if (!Solver(txout.scriptPubKey, hash, nHashType, txin.scriptSig))
+        return false;
+
+    txin.scriptSig = scriptPrereq + txin.scriptSig;
+
+    // Test solution
+    if (scriptPrereq.empty())
+        if (!VerifyScript(txin.scriptSig, txout.scriptPubKey, txTo, nIn, 0))
+            return false;
+
+    return true;
+}
+
+
+bool VerifySignature(const CTransaction& txFrom, const CTransaction& txTo, unsigned int nIn, int nHashType)
+{
+    assert(nIn < txTo.vin.size());
+    const CTxIn& txin = txTo.vin[nIn];
+    if (txin.prevout.n >= txFrom.vout.size())
+        return false;
+    const CTxOut& txout = txFrom.vout[txin.prevout.n];
+
+    if (txin.prevout.hash != txFrom.GetHash())
+        return false;
+
+    if (!VerifyScript(txin.scriptSig, txout.scriptPubKey, txTo, nIn, nHashType))
+        return false;
+
+    // Anytime a signature is successfully verified, it's proof the outpoint is spent,
+    // so lets update the wallet spent flag if it doesn't know due to wallet.dat being
+    // restored from backup or the user making copies of wallet.dat.
+    WalletUpdateSpent(txin.prevout);
+
+    return true;
+}