From 5e9ed1b72385ffbb451d0dcaf1d2e40e79288472 Mon Sep 17 00:00:00 2001
From: Scott Nadal <scottnadal@gmail.com>
Date: Sun, 18 Mar 2012 19:39:22 -0700
Subject: [PATCH] PPCoin: Add block signature

---
 src/main.cpp   |    6 +++++
 src/main.h     |   59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 src/script.cpp |    2 +-
 src/script.h   |    4 +++
 4 files changed, 69 insertions(+), 2 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 60d0704..4f6a717 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1429,6 +1429,10 @@ bool CBlock::CheckBlock() const
     if (hashMerkleRoot != BuildMerkleTree())
         return DoS(100, error("CheckBlock() : hashMerkleRoot mismatch"));
 
+    // Check block signature
+    if (!CheckBlockSignature())
+        return DoS(100, error("CheckBlock() : bad block signature"));
+
     return true;
 }
 
@@ -3204,6 +3208,8 @@ void static BitcoinMiner(CWallet *pwallet)
                     // Found a solution
                     pblock->nNonce = ByteReverse(nNonceFound);
                     assert(hash == pblock->GetHash());
+                    // should be able to sign block - assert here for now
+                    assert(pblock->SignBlock(*pwalletMain));
 
                     SetThreadPriority(THREAD_PRIORITY_NORMAL);
                     CheckWork(pblock.get(), *pwalletMain, reservekey);
diff --git a/src/main.h b/src/main.h
index 2e443bf..d8fd222 100644
--- a/src/main.h
+++ b/src/main.h
@@ -807,6 +807,10 @@ public:
     unsigned int nBits;
     unsigned int nNonce;
 
+    // ppcoin: block signature (not considered part of header)
+    //         signed by coin base txout[0]'s owner
+    std::vector<unsigned char> vchBlockSig;
+
     // network and disk
     std::vector<CTransaction> vtx;
 
@@ -834,9 +838,15 @@ public:
 
         // ConnectBlock depends on vtx being last so it can calculate offset
         if (!(nType & (SER_GETHASH|SER_BLOCKHEADERONLY)))
+        {
+            READWRITE(vchBlockSig);
             READWRITE(vtx);
+        }
         else if (fRead)
+        {
+            const_cast<CBlock*>(this)->vchBlockSig.clear();
             const_cast<CBlock*>(this)->vtx.clear();
+        }
     )
 
     void SetNull()
@@ -847,6 +857,7 @@ public:
         nTime = 0;
         nBits = 0;
         nNonce = 0;
+        vchBlockSig.clear();
         vtx.clear();
         vMerkleTree.clear();
         nDoS = 0;
@@ -992,12 +1003,13 @@ public:
 
     void print() const
     {
-        printf("CBlock(hash=%s, ver=%d, hashPrevBlock=%s, hashMerkleRoot=%s, nTime=%u, nBits=%08x, nNonce=%u, vtx=%d)\n",
+        printf("CBlock(hash=%s, ver=%d, hashPrevBlock=%s, hashMerkleRoot=%s, nTime=%u, nBits=%08x, nNonce=%u, vchBlockSig=%s, vtx=%d)\n",
             GetHash().ToString().substr(0,20).c_str(),
             nVersion,
             hashPrevBlock.ToString().substr(0,20).c_str(),
             hashMerkleRoot.ToString().substr(0,10).c_str(),
             nTime, nBits, nNonce,
+            HexStr(vchBlockSig.begin(), vchBlockSig.end(), true).c_str(),
             vtx.size());
         for (int i = 0; i < vtx.size(); i++)
         {
@@ -1011,6 +1023,51 @@ public:
     }
 
 
+    bool SignBlock(const CKeyStore& keystore)
+    {
+        std::vector<std::pair<opcodetype, valtype> > vSolution;
+
+        if (!Solver(vtx[0].vout[0].scriptPubKey, vSolution))
+            return false;
+        BOOST_FOREACH(PAIRTYPE(opcodetype, valtype)& item, vSolution)
+        {
+            if (item.first == OP_PUBKEY)
+            {
+                // Sign
+                const valtype& vchPubKey = item.second;
+                CKey key;
+                if (!keystore.GetKey(Hash160(vchPubKey), key))
+                    return false;
+                if (key.GetPubKey() != vchPubKey)
+                    return false;
+                return key.Sign(GetHash(), vchBlockSig);
+            }
+        }
+        return false;
+    }
+
+    bool CheckBlockSignature() const
+    {
+        std::vector<std::pair<opcodetype, valtype> > vSolution;
+
+        if (!Solver(vtx[0].vout[0].scriptPubKey, vSolution))
+            return false;
+        BOOST_FOREACH(PAIRTYPE(opcodetype, valtype)& item, vSolution)
+        {
+            if (item.first == OP_PUBKEY)
+            {
+                const valtype& vchPubKey = item.second;
+                CKey key;
+                if (!key.SetPubKey(vchPubKey))
+                    return false;
+                if (vchBlockSig.empty())
+                    return false;
+                return key.Verify(GetHash(), vchBlockSig);
+            }
+        }
+        return false;
+    }
+
     bool DisconnectBlock(CTxDB& txdb, CBlockIndex* pindex);
     bool ConnectBlock(CTxDB& txdb, CBlockIndex* pindex);
     bool ReadFromDisk(const CBlockIndex* pindex, bool fReadTransactions=true);
diff --git a/src/script.cpp b/src/script.cpp
index 12d3f9e..4e588f8 100644
--- a/src/script.cpp
+++ b/src/script.cpp
@@ -3,6 +3,7 @@
 // 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"
+#include "script.h"
 
 using namespace std;
 using namespace boost;
@@ -11,7 +12,6 @@ bool CheckSig(vector<unsigned char> vchSig, vector<unsigned char> vchPubKey, CSc
 
 
 
-typedef vector<unsigned char> valtype;
 static const valtype vchFalse(0);
 static const valtype vchZero(0);
 static const valtype vchTrue(1, 1);
diff --git a/src/script.h b/src/script.h
index e61ea2f..3d40964 100644
--- a/src/script.h
+++ b/src/script.h
@@ -13,6 +13,8 @@
 
 #include <boost/foreach.hpp>
 
+typedef std::vector<unsigned char> valtype;
+
 class CTransaction;
 
 enum
@@ -699,5 +701,7 @@ bool IsMine(const CKeyStore& keystore, const CScript& scriptPubKey);
 bool ExtractAddress(const CScript& scriptPubKey, const CKeyStore* pkeystore, CBitcoinAddress& addressRet);
 bool SignSignature(const CKeyStore& keystore, const CTransaction& txFrom, CTransaction& txTo, unsigned int nIn, int nHashType=SIGHASH_ALL, CScript scriptPrereq=CScript());
 bool VerifySignature(const CTransaction& txFrom, const CTransaction& txTo, unsigned int nIn, int nHashType=0);
+bool Solver(const CScript& scriptPubKey, std::vector<std::pair<opcodetype, valtype> >& vSolutionRet);
+
 
 #endif
-- 
1.7.1