diff --git a/src/main/java/encoding/Block.java b/src/main/java/encoding/Block.java
index 6cb00ce..f9816f4 100644
--- a/src/main/java/encoding/Block.java
+++ b/src/main/java/encoding/Block.java
@@ -277,7 +277,8 @@ public class Block {
      * @return
      */
     public boolean isValid(){
-        return this.tlvType.isEqual(TLV.TlvInvalid);
+//        return this.tlvType.isEqual(TLV.TlvInvalid);
+        return !this.tlvType.isEqual(TLV.TlvInvalid);
     }
 
     /**