diff --git a/src/name-assignments/assignment-funcs.hpp b/src/name-assignments/assignment-funcs.hpp
new file mode 100644
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+++ b/src/name-assignments/assignment-funcs.hpp
@@ -0,0 +1,78 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2017-2019, Regents of the University of California.
+ *
+ * This file is part of ndncert, a certificate management system based on NDN.
+ *
+ * ndncert is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation, either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * ndncert is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License along with
+ * ndncert, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ndncert authors and contributors.
+ */
+
+#ifndef NDNCERT_ASSIGNMENT_FUNCS_HPP
+#define NDNCERT_ASSIGNMENT_FUNCS_HPP
+
+#include <configuration.hpp>
+#include "ca-state.hpp"
+
+namespace ndn {
+namespace ndncert {
+
+class NameAssignmentFuncFactory : noncopyable {
+public:
+  explicit
+  NameAssignmentFuncFactory(const std::string& factoryType);
+
+  virtual ~NameAssignmentFuncFactory() = default;
+
+  template <class ChallengeType>
+  static void
+  registerNameAssignmentFuncFactorys(const std::string& typeName)
+  {
+    FuncFactoryFactory& factory = getFactory();
+    BOOST_ASSERT(factory.count(typeName) == 0);
+    factory[typeName] = [] { return make_unique<ChallengeType>(); };
+  }
+
+  static bool
+  isChallengeSupported(const std::string& challengeType);
+
+  static unique_ptr<NameAssignmentFuncFactory>
+  createNameAssignmentConfigFuncs(const std::string& challengeType);
+
+  virtual NameAssignmentFunc
+  getFunction(const std::string& factoryParam) = 0;
+
+public:
+  const std::string FACTORY_TYPE;
+
+private:
+  typedef function<unique_ptr<NameAssignmentFuncFactory>()> FactoryCreateFunc;
+  typedef std::map<std::string, FactoryCreateFunc> FuncFactoryFactory;
+
+  static FuncFactoryFactory&
+  getFactory();
+};
+
+#define NDNCERT_REGISTER_FUNCFACTORY(C, T)                              \
+  static class NdnCert##C##FuncFactoryRegistrationClass {               \
+  public:                                                             \
+    NdnCert##C##FuncFactoryRegistrationClass()                          \
+    {                                                                 \
+      ::ndn::ndncert::NameAssignmentFuncFactory::registerNameAssignmentFuncFactorys<C>(T); \
+    }                                                                 \
+  } g_NdnCert##C##ChallengeRegistrationVariable
+
+}  // namespace ndncert
+}  // namespace ndn
+
+#endif  // NDNCERT_ASSIGNMENT_FUNCS_HPP