diff --git a/src/security/validity-period.cpp b/src/security/validity-period.cpp
index 14ba0f2..c30497b 100644
--- a/src/security/validity-period.cpp
+++ b/src/security/validity-period.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2013-2016 Regents of the University of California.
+/*
+ * Copyright (c) 2013-2017 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -72,11 +72,7 @@
   return totalLength;
 }
 
-template size_t
-ValidityPeriod::wireEncode<encoding::EncoderTag>(EncodingImpl<encoding::EncoderTag>& encoder) const;
-
-template size_t
-ValidityPeriod::wireEncode<encoding::EstimatorTag>(EncodingImpl<encoding::EstimatorTag>& encoder) const;
+NDN_CXX_DEFINE_WIRE_ENCODE_INSTANTIATIONS(ValidityPeriod);
 
 const Block&
 ValidityPeriod::wireEncode() const