1 files changed, 260 insertions, 0 deletions
diff --git a/src/script/sign.cpp b/src/script/sign.cpp
new file mode 100644
index 0000000000..958177de3d
--- /dev/null
+++ b/src/script/sign.cpp
@@ -0,0 +1,260 @@
+// 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.
+
+#include "script/sign.h"
+
+#include "core.h"
+#include "key.h"
+#include "keystore.h"
+#include "script/standard.h"
+#include "uint256.h"
+
+#include <boost/foreach.hpp>
+
+using namespace std;
+
+typedef vector<unsigned char> valtype;
+
+bool Sign1(const CKeyID& address, const CKeyStore& keystore, uint256 hash, int nHashType, CScript& scriptSigRet)
+{
+    CKey key;
+    if (!keystore.GetKey(address, key))
+        return false;
+
+    vector<unsigned char> vchSig;
+    if (!key.Sign(hash, vchSig))
+        return false;
+    vchSig.push_back((unsigned char)nHashType);
+    scriptSigRet << vchSig;
+
+    return true;
+}
+
+bool SignN(const vector<valtype>& multisigdata, const CKeyStore& keystore, uint256 hash, int nHashType, CScript& scriptSigRet)
+{
+    int nSigned = 0;
+    int nRequired = multisigdata.front()[0];
+    for (unsigned int i = 1; i < multisigdata.size()-1 && nSigned < nRequired; i++)
+    {
+        const valtype& pubkey = multisigdata[i];
+        CKeyID keyID = CPubKey(pubkey).GetID();
+        if (Sign1(keyID, keystore, hash, nHashType, scriptSigRet))
+            ++nSigned;
+    }
+    return nSigned==nRequired;
+}
+
+//
+// Sign scriptPubKey with private keys stored in keystore, given transaction hash and hash type.
+// Signatures are returned in scriptSigRet (or returns false if scriptPubKey can't be signed),
+// unless whichTypeRet is TX_SCRIPTHASH, in which case scriptSigRet is the redemption script.
+// Returns false if scriptPubKey could not be completely satisfied.
+//
+bool Solver(const CKeyStore& keystore, const CScript& scriptPubKey, uint256 hash, int nHashType,
+                  CScript& scriptSigRet, txnouttype& whichTypeRet)
+{
+    scriptSigRet.clear();
+
+    vector<valtype> vSolutions;
+    if (!Solver(scriptPubKey, whichTypeRet, vSolutions))
+        return false;
+
+    CKeyID keyID;
+    switch (whichTypeRet)
+    {
+    case TX_NONSTANDARD:
+    case TX_NULL_DATA:
+        return false;
+    case TX_PUBKEY:
+        keyID = CPubKey(vSolutions[0]).GetID();
+        return Sign1(keyID, keystore, hash, nHashType, scriptSigRet);
+    case TX_PUBKEYHASH:
+        keyID = CKeyID(uint160(vSolutions[0]));
+        if (!Sign1(keyID, keystore, hash, nHashType, scriptSigRet))
+            return false;
+        else
+        {
+            CPubKey vch;
+            keystore.GetPubKey(keyID, vch);
+            scriptSigRet << vch;
+        }
+        return true;
+    case TX_SCRIPTHASH:
+        return keystore.GetCScript(uint160(vSolutions[0]), scriptSigRet);
+
+    case TX_MULTISIG:
+        scriptSigRet << OP_0; // workaround CHECKMULTISIG bug
+        return (SignN(vSolutions, keystore, hash, nHashType, scriptSigRet));
+    }
+    return false;
+}
+
+bool SignSignature(const CKeyStore &keystore, const CScript& fromPubKey, CMutableTransaction& txTo, unsigned int nIn, int nHashType)
+{
+    assert(nIn < txTo.vin.size());
+    CTxIn& txin = txTo.vin[nIn];
+
+    // 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(fromPubKey, txTo, nIn, nHashType);
+
+    txnouttype whichType;
+    if (!Solver(keystore, fromPubKey, hash, nHashType, txin.scriptSig, whichType))
+        return false;
+
+    if (whichType == TX_SCRIPTHASH)
+    {
+        // Solver returns the subscript that need to be evaluated;
+        // the final scriptSig is the signatures from that
+        // and then the serialized subscript:
+        CScript subscript = txin.scriptSig;
+
+        // Recompute txn hash using subscript in place of scriptPubKey:
+        uint256 hash2 = SignatureHash(subscript, txTo, nIn, nHashType);
+
+        txnouttype subType;
+        bool fSolved =
+            Solver(keystore, subscript, hash2, nHashType, txin.scriptSig, subType) && subType != TX_SCRIPTHASH;
+        // Append serialized subscript whether or not it is completely signed:
+        txin.scriptSig << static_cast<valtype>(subscript);
+        if (!fSolved) return false;
+    }
+
+    // Test solution
+    return VerifyScript(txin.scriptSig, fromPubKey, txTo, nIn, STANDARD_SCRIPT_VERIFY_FLAGS, 0);
+}
+
+bool SignSignature(const CKeyStore &keystore, const CTransaction& txFrom, CMutableTransaction& txTo, unsigned int nIn, int nHashType)
+{
+    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];
+
+    return SignSignature(keystore, txout.scriptPubKey, txTo, nIn, nHashType);
+}
+
+static CScript PushAll(const vector<valtype>& values)
+{
+    CScript result;
+    BOOST_FOREACH(const valtype& v, values)
+        result << v;
+    return result;
+}
+
+static CScript CombineMultisig(CScript scriptPubKey, const CMutableTransaction& txTo, unsigned int nIn,
+                               const vector<valtype>& vSolutions,
+                               vector<valtype>& sigs1, vector<valtype>& sigs2)
+{
+    // Combine all the signatures we've got:
+    set<valtype> allsigs;
+    BOOST_FOREACH(const valtype& v, sigs1)
+    {
+        if (!v.empty())
+            allsigs.insert(v);
+    }
+    BOOST_FOREACH(const valtype& v, sigs2)
+    {
+        if (!v.empty())
+            allsigs.insert(v);
+    }
+
+    // Build a map of pubkey -> signature by matching sigs to pubkeys:
+    assert(vSolutions.size() > 1);
+    unsigned int nSigsRequired = vSolutions.front()[0];
+    unsigned int nPubKeys = vSolutions.size()-2;
+    map<valtype, valtype> sigs;
+    BOOST_FOREACH(const valtype& sig, allsigs)
+    {
+        for (unsigned int i = 0; i < nPubKeys; i++)
+        {
+            const valtype& pubkey = vSolutions[i+1];
+            if (sigs.count(pubkey))
+                continue; // Already got a sig for this pubkey
+
+            if (CheckSig(sig, pubkey, scriptPubKey, txTo, nIn, 0, 0))
+            {
+                sigs[pubkey] = sig;
+                break;
+            }
+        }
+    }
+    // Now build a merged CScript:
+    unsigned int nSigsHave = 0;
+    CScript result; result << OP_0; // pop-one-too-many workaround
+    for (unsigned int i = 0; i < nPubKeys && nSigsHave < nSigsRequired; i++)
+    {
+        if (sigs.count(vSolutions[i+1]))
+        {
+            result << sigs[vSolutions[i+1]];
+            ++nSigsHave;
+        }
+    }
+    // Fill any missing with OP_0:
+    for (unsigned int i = nSigsHave; i < nSigsRequired; i++)
+        result << OP_0;
+
+    return result;
+}
+
+static CScript CombineSignatures(CScript scriptPubKey, const CTransaction& txTo, unsigned int nIn,
+                                 const txnouttype txType, const vector<valtype>& vSolutions,
+                                 vector<valtype>& sigs1, vector<valtype>& sigs2)
+{
+    switch (txType)
+    {
+    case TX_NONSTANDARD:
+    case TX_NULL_DATA:
+        // Don't know anything about this, assume bigger one is correct:
+        if (sigs1.size() >= sigs2.size())
+            return PushAll(sigs1);
+        return PushAll(sigs2);
+    case TX_PUBKEY:
+    case TX_PUBKEYHASH:
+        // Signatures are bigger than placeholders or empty scripts:
+        if (sigs1.empty() || sigs1[0].empty())
+            return PushAll(sigs2);
+        return PushAll(sigs1);
+    case TX_SCRIPTHASH:
+        if (sigs1.empty() || sigs1.back().empty())
+            return PushAll(sigs2);
+        else if (sigs2.empty() || sigs2.back().empty())
+            return PushAll(sigs1);
+        else
+        {
+            // Recur to combine:
+            valtype spk = sigs1.back();
+            CScript pubKey2(spk.begin(), spk.end());
+
+            txnouttype txType2;
+            vector<vector<unsigned char> > vSolutions2;
+            Solver(pubKey2, txType2, vSolutions2);
+            sigs1.pop_back();
+            sigs2.pop_back();
+            CScript result = CombineSignatures(pubKey2, txTo, nIn, txType2, vSolutions2, sigs1, sigs2);
+            result << spk;
+            return result;
+        }
+    case TX_MULTISIG:
+        return CombineMultisig(scriptPubKey, txTo, nIn, vSolutions, sigs1, sigs2);
+    }
+
+    return CScript();
+}
+
+CScript CombineSignatures(CScript scriptPubKey, const CTransaction& txTo, unsigned int nIn,
+                          const CScript& scriptSig1, const CScript& scriptSig2)
+{
+    txnouttype txType;
+    vector<vector<unsigned char> > vSolutions;
+    Solver(scriptPubKey, txType, vSolutions);
+
+    vector<valtype> stack1;
+    EvalScript(stack1, scriptSig1, CTransaction(), 0, SCRIPT_VERIFY_STRICTENC, 0);
+    vector<valtype> stack2;
+    EvalScript(stack2, scriptSig2, CTransaction(), 0, SCRIPT_VERIFY_STRICTENC, 0);
+
+    return CombineSignatures(scriptPubKey, txTo, nIn, txType, vSolutions, stack1, stack2);
+}