diff --git a/include/block.inc.php b/include/block.inc.php
index f742859..f501877 100755
--- a/include/block.inc.php
+++ b/include/block.inc.php
@@ -267,10 +267,10 @@ $this->reset_fails_masternodes($mn_winner, $height, $hash);
             }
 	}elseif($height>=80458){
 		 $type=$height%2;
-		$current=$db->row("SELECT difficulty from blocks ORDER by height DESC LIMIT 1,1");
+		$current=$db->row("SELECT difficulty from blocks WHERE height<=:h ORDER by height DESC LIMIT 1,1",[":h"=>$height]);
             $blks=0;
             $total_time=0;
-            $blk = $db->run("SELECT `date`, height FROM blocks  ORDER by height DESC LIMIT 20");
+            $blk = $db->run("SELECT `date`, height FROM blocks WHERE height<=:h  ORDER by height DESC LIMIT 20",[":h"=>$height]);
             for ($i=0;$i<19;$i++) {
                 $ctype=$blk[$i+1]['height']%2;
                 $time=$blk[$i]['date']-$blk[$i+1]['date'];
diff --git a/include/transaction.inc.php b/include/transaction.inc.php
index 88ca382..d9c3494 100755
--- a/include/transaction.inc.php
+++ b/include/transaction.inc.php
@@ -378,6 +378,10 @@ class Transaction
                     _log("The Masternode IP is invalid", 3);
                     return false;
                 }
+		$existing=$db->single("SELECT COUNT(1) FROM masternode WHERE public_key=:id or ip=:ip",["id"=>$x['public_key'], ":ip"=>$message]);
+		if($existing!=0){
+			return false;
+		}
             }
            
         
diff --git a/util.php b/util.php
index 3fbb435..2b18278 100755
--- a/util.php
+++ b/util.php
@@ -93,7 +93,7 @@ elseif ($cmd == 'block-time') {
         }
         $time = $t - $x['date'];
         $t = $x['date'];
-        echo "$x[height] -> $time\n";
+        echo "$x[height]\t\t$time\t\t$x[difficulty]\n";
         $end = $x['date'];
     }
     echo "Average block time: ".ceil(($start - $end) / 100)." seconds\n";