New syncronized checkpoints policy: no immediate PoW block checkpointing.

diff --git a/src/checkpoints.cpp b/src/checkpoints.cpp
index f9c3c2e..a64243a 100644 (file)
--- a/src/checkpoints.cpp
+++ b/src/checkpoints.cpp
@@ -128,7 +128,7 @@ namespace Checkpoints
             CBlockIndex* pindex = pindexSyncCheckpoint;
             while (pindex->nHeight > pindexCheckpointRecv->nHeight)
                 if (!(pindex = pindex->pprev))
-                    return error("ValidateSyncCheckpoint: pprev1 null - block index structure failure");
+                    return error("ValidateSyncCheckpoint: pprev null - block index structure failure");
             if (pindex->GetBlockHash() != hashCheckpoint)
             {
                 hashInvalidCheckpoint = hashCheckpoint;
@@ -221,14 +221,10 @@ namespace Checkpoints
     // Automatically select a suitable sync-checkpoint 
     uint256 AutoSelectSyncCheckpoint()
     {
-        // Proof-of-work blocks are immediately checkpointed
-        // to defend against 51% attack which rejects other miners block 
-
-        // Select the last proof-of-work block
-        const CBlockIndex *pindex = GetLastBlockIndex(pindexBest, false);
-        // Search forward for a block within max span and maturity window
-        while (pindex->pnext && (pindex->GetBlockTime() + CHECKPOINT_MAX_SPAN <= pindexBest->GetBlockTime() || pindex->nHeight + std::min(6, nCoinbaseMaturity - 20) <= pindexBest->nHeight))
-            pindex = pindex->pnext;
+        const CBlockIndex *pindex = pindexBest;
+        // Search backward for a block within max span and maturity window
+        while (pindex->pprev && (pindex->GetBlockTime() + CHECKPOINT_MAX_SPAN > pindexBest->GetBlockTime() || pindex->nHeight + 8 > pindexBest->nHeight))
+            pindex = pindex->pprev;
         return pindex->GetBlockHash();
     }
 

diff --git a/src/checkpoints.h b/src/checkpoints.h
index a8e7ecb..fedcf36 100644 (file)
--- a/src/checkpoints.h
+++ b/src/checkpoints.h
@@ -8,7 +8,7 @@
 #include "net.h"
 #include "util.h"
 
-#define CHECKPOINT_MAX_SPAN (60 * 60 * 4) // max 4 hours before latest block
+#define CHECKPOINT_MAX_SPAN (60 * 60) // max 1 hour before latest block
 
 #ifdef WIN32
 #undef STRICT