diff --git a/src/security/validity-period.hpp b/src/security/validity-period.hpp
index e87c6ec..ee7c602 100644
--- a/src/security/validity-period.hpp
+++ b/src/security/validity-period.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2017 Regents of the University of California.
+ * Copyright (c) 2013-2018 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -40,11 +40,7 @@
   class Error : public tlv::Error
   {
   public:
-    explicit
-    Error(const std::string& what)
-      : tlv::Error(what)
-    {
-    }
+    using tlv::Error::Error;
   };
 
 public: