diff --git a/src/encoding/block-helpers.hpp b/src/encoding/block-helpers.hpp
index 5634ed6..c66c0b9 100644
--- a/src/encoding/block-helpers.hpp
+++ b/src/encoding/block-helpers.hpp
@@ -26,8 +26,6 @@
 #include "encoding-buffer.hpp"
 #include "../util/concepts.hpp"
 
-#include <iterator>
-
 namespace ndn {
 namespace encoding {
 
@@ -233,8 +231,6 @@
 Block
 makeBinaryBlock(uint32_t type, Iterator first, Iterator last)
 {
-  static_assert(sizeof(typename std::iterator_traits<Iterator>::value_type) == 1, "");
-
   using BinaryBlockHelper = typename std::conditional<
     std::is_base_of<std::random_access_iterator_tag,
                     typename std::iterator_traits<Iterator>::iterator_category>::value,
diff --git a/src/encoding/encoder.hpp b/src/encoding/encoder.hpp
index 28b2fa1..06a7ca1 100644
--- a/src/encoding/encoder.hpp
+++ b/src/encoding/encoder.hpp
@@ -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).
  *
@@ -22,7 +22,6 @@
 #ifndef NDN_ENCODING_ENCODER_HPP
 #define NDN_ENCODING_ENCODER_HPP
 
-#include "../common.hpp"
 #include "block.hpp"
 
 namespace ndn {
@@ -140,9 +139,9 @@
   appendBlock(const Block& block);
 
 public: // unique interface to the Encoder
-  typedef Buffer::value_type value_type;
-  typedef Buffer::iterator iterator;
-  typedef Buffer::const_iterator const_iterator;
+  using value_type = Buffer::value_type;
+  using iterator = Buffer::iterator;
+  using const_iterator = Buffer::const_iterator;
 
   /**
    * @brief Create EncodingBlock from existing block
@@ -316,6 +315,9 @@
 inline size_t
 Encoder::prependRange(Iterator first, Iterator last)
 {
+  using ValueType = typename std::iterator_traits<Iterator>::value_type;
+  static_assert(sizeof(ValueType) == 1 && !std::is_same<ValueType, bool>::value, "");
+
   size_t length = std::distance(first, last);
   reserveFront(length);
 
@@ -329,6 +331,9 @@
 inline size_t
 Encoder::appendRange(Iterator first, Iterator last)
 {
+  using ValueType = typename std::iterator_traits<Iterator>::value_type;
+  static_assert(sizeof(ValueType) == 1 && !std::is_same<ValueType, bool>::value, "");
+
   size_t length = std::distance(first, last);
   reserveBack(length);