diff --git a/src/name-assignments/assignment-funcs.cpp b/src/name-assignments/assignment-funcs.cpp
new file mode 100644
index 0000000..7e806f8
--- /dev/null
+++ b/src/name-assignments/assignment-funcs.cpp
@@ -0,0 +1,56 @@
+/* -*- 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.
+ */
+
+#include "assignment-funcs.hpp"
+#include <ndn-cxx/util/random.hpp>
+
+namespace ndn {
+namespace ndncert {
+
+NameAssignmentFuncFactory::NameAssignmentFuncFactory(const std::string& factoryType)
+  : FACTORY_TYPE(factoryType)
+{
+}
+
+bool
+NameAssignmentFuncFactory::isChallengeSupported(const std::string& challengeType)
+{
+  FuncFactoryFactory& factory = getFactory();
+  auto i = factory.find(challengeType);
+  return i != factory.end();
+}
+
+unique_ptr<NameAssignmentFuncFactory>
+NameAssignmentFuncFactory::createNameAssignmentConfigFuncs(const std::string& challengeType)
+{
+  FuncFactoryFactory& factory = getFactory();
+  auto i = factory.find(challengeType);
+  return i == factory.end() ? nullptr : i->second();
+}
+
+NameAssignmentFuncFactory::FuncFactoryFactory&
+NameAssignmentFuncFactory::getFactory()
+{
+  static NameAssignmentFuncFactory::FuncFactoryFactory factory;
+  return factory;
+}
+
+} // namespace ndncert
+} // namespace ndn