diff --git a/ndnboost/type_traits/is_signed.hpp b/ndnboost/type_traits/is_signed.hpp
new file mode 100644
index 0000000..1697dee
--- /dev/null
+++ b/ndnboost/type_traits/is_signed.hpp
@@ -0,0 +1,140 @@
+
+//  (C) Copyright John Maddock 2005.  
+//  Use, modification and distribution are subject to the Boost Software License,
+//  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+//  http://www.boost.org/LICENSE_1_0.txt).
+//
+//  See http://www.boost.org/libs/type_traits for most recent version including documentation.
+
+
+#ifndef BOOST_TT_IS_SIGNED_HPP_INCLUDED
+#define BOOST_TT_IS_SIGNED_HPP_INCLUDED
+
+#include <ndnboost/type_traits/is_integral.hpp>
+#include <ndnboost/type_traits/remove_cv.hpp>
+#include <ndnboost/type_traits/is_enum.hpp>
+#include <ndnboost/type_traits/detail/ice_or.hpp>
+
+// should be the last #include
+#include <ndnboost/type_traits/detail/bool_trait_def.hpp>
+
+namespace ndnboost {
+
+#if !defined( __CODEGEARC__ )
+
+namespace detail{
+
+#if !(defined(__EDG_VERSION__) && __EDG_VERSION__ <= 238) && !defined(BOOST_NO_INCLASS_MEMBER_INITIALIZATION)
+
+template <class T>
+struct is_signed_values
+{
+   //
+   // Note that we cannot use BOOST_STATIC_CONSTANT here, using enum's
+   // rather than "real" static constants simply doesn't work or give
+   // the correct answer.
+   //
+   typedef typename remove_cv<T>::type no_cv_t;
+   static const no_cv_t minus_one = (static_cast<no_cv_t>(-1));
+   static const no_cv_t zero = (static_cast<no_cv_t>(0));
+};
+
+template <class T>
+struct is_signed_helper
+{
+   typedef typename remove_cv<T>::type no_cv_t;
+   BOOST_STATIC_CONSTANT(bool, value = (!(::ndnboost::detail::is_signed_values<T>::minus_one  > ndnboost::detail::is_signed_values<T>::zero)));
+};
+
+template <bool integral_type>
+struct is_signed_select_helper
+{
+   template <class T>
+   struct rebind
+   {
+      typedef is_signed_helper<T> type;
+   };
+};
+
+template <>
+struct is_signed_select_helper<false>
+{
+   template <class T>
+   struct rebind
+   {
+      typedef false_type type;
+   };
+};
+
+template <class T>
+struct is_signed_imp
+{
+   typedef is_signed_select_helper< 
+      ::ndnboost::type_traits::ice_or<
+         ::ndnboost::is_integral<T>::value,
+         ::ndnboost::is_enum<T>::value>::value 
+   > selector;
+   typedef typename selector::template rebind<T> binder;
+   typedef typename binder::type type;
+#if defined(BOOST_MSVC) && (BOOST_MSVC < 1300)
+   BOOST_STATIC_CONSTANT(bool, value = is_signed_imp<T>::type::value);
+#else
+   BOOST_STATIC_CONSTANT(bool, value = type::value);
+#endif
+};
+
+#else
+
+template <class T> struct is_signed_imp : public false_type{};
+template <> struct is_signed_imp<signed char> : public true_type{};
+template <> struct is_signed_imp<const signed char> : public true_type{};
+template <> struct is_signed_imp<volatile signed char> : public true_type{};
+template <> struct is_signed_imp<const volatile signed char> : public true_type{};
+template <> struct is_signed_imp<short> : public true_type{};
+template <> struct is_signed_imp<const short> : public true_type{};
+template <> struct is_signed_imp<volatile short> : public true_type{};
+template <> struct is_signed_imp<const volatile short> : public true_type{};
+template <> struct is_signed_imp<int> : public true_type{};
+template <> struct is_signed_imp<const int> : public true_type{};
+template <> struct is_signed_imp<volatile int> : public true_type{};
+template <> struct is_signed_imp<const volatile int> : public true_type{};
+template <> struct is_signed_imp<long> : public true_type{};
+template <> struct is_signed_imp<const long> : public true_type{};
+template <> struct is_signed_imp<volatile long> : public true_type{};
+template <> struct is_signed_imp<const volatile long> : public true_type{};
+#ifdef BOOST_HAS_LONG_LONG
+template <> struct is_signed_imp<long long> : public true_type{};
+template <> struct is_signed_imp<const long long> : public true_type{};
+template <> struct is_signed_imp<volatile long long> : public true_type{};
+template <> struct is_signed_imp<const volatile long long> : public true_type{};
+#endif
+#if defined(CHAR_MIN) && (CHAR_MIN != 0)
+template <> struct is_signed_imp<char> : public true_type{};
+template <> struct is_signed_imp<const char> : public true_type{};
+template <> struct is_signed_imp<volatile char> : public true_type{};
+template <> struct is_signed_imp<const volatile char> : public true_type{};
+#endif
+#if defined(WCHAR_MIN) && (WCHAR_MIN != 0)
+template <> struct is_signed_imp<wchar_t> : public true_type{};
+template <> struct is_signed_imp<const wchar_t> : public true_type{};
+template <> struct is_signed_imp<volatile wchar_t> : public true_type{};
+template <> struct is_signed_imp<const volatile wchar_t> : public true_type{};
+#endif
+
+#endif
+
+}
+
+#endif // !defined( __CODEGEARC__ )
+
+#if defined( __CODEGEARC__ )
+BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_signed,T,__is_signed(T))
+#else
+BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_signed,T,::ndnboost::detail::is_signed_imp<T>::value)
+#endif
+
+} // namespace ndnboost
+
+#include <ndnboost/type_traits/detail/bool_trait_undef.hpp>
+
+#endif // BOOST_TT_IS_MEMBER_FUNCTION_POINTER_HPP_INCLUDED