diff --git a/src/security/transform/transform-base.cpp b/src/security/transform/transform-base.cpp
index b04c3f5..2a65281 100644
--- a/src/security/transform/transform-base.cpp
+++ b/src/security/transform/transform-base.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).
  *
@@ -26,7 +26,7 @@
 namespace transform {
 
 Error::Error(size_t index, const std::string& what)
-  : std::runtime_error("Error in module " + std::to_string(index) + ": " + what)
+  : std::runtime_error("Error in module " + to_string(index) + ": " + what)
   , m_index(index)
 {
 }