In PublisherPublicKeyDigest, make the value a Blob.
diff --git a/ndn-cpp/key.hpp b/ndn-cpp/key.hpp
index 0717e1b..9f4f30e 100644
--- a/ndn-cpp/key.hpp
+++ b/ndn-cpp/key.hpp
@@ -26,7 +26,7 @@
   {
     type_ = (ndn_KeyLocatorType)-1;
     keyNameType_ = (ndn_KeyNameType)-1;
-    keyData_ = Blob(0, 0);
+    keyData_.reset();
   }
   
   /**