diff --git a/src/name-assignment/assignment-func.cpp b/src/name-assignment/assignment-func.cpp
index d65eefd..f4728d3 100644
--- a/src/name-assignment/assignment-func.cpp
+++ b/src/name-assignment/assignment-func.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -19,9 +19,7 @@
  */
 
 #include "assignment-func.hpp"
-#include <ndn-cxx/util/random.hpp>
 
-namespace ndn {
 namespace ndncert {
 
 NameAssignmentFunc::NameAssignmentFunc(const std::string& format)
@@ -39,7 +37,7 @@
   }
 }
 
-unique_ptr<NameAssignmentFunc>
+std::unique_ptr<NameAssignmentFunc>
 NameAssignmentFunc::createNameAssignmentFunc(const std::string& challengeType, const std::string& format)
 {
   CurriedFuncFactory& factory = getFactory();
@@ -55,4 +53,3 @@
 }
 
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/name-assignment/assignment-func.hpp b/src/name-assignment/assignment-func.hpp
index 9e9b128..7f35fcf 100644
--- a/src/name-assignment/assignment-func.hpp
+++ b/src/name-assignment/assignment-func.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -22,12 +22,12 @@
 #define NDNCERT_ASSIGNMENT_FUNC_HPP
 
 #include "detail/ca-request-state.hpp"
+
 #include <map>
 
-namespace ndn {
 namespace ndncert {
 
-class NameAssignmentFunc : noncopyable
+class NameAssignmentFunc : boost::noncopyable
 {
 protected:
   explicit NameAssignmentFunc(const std::string& format = "");
@@ -45,7 +45,7 @@
    * @param vector A list of parameter key-value pair used for name assignment.
    * @return a vector containing the possible namespaces derived from the parameters.
    */
-  virtual std::vector<PartialName>
+  virtual std::vector<ndn::PartialName>
   assignName(const std::multimap<std::string, std::string>& params) = 0;
 
 public:
@@ -58,14 +58,14 @@
     factory[typeName] = [](const std::string& format) { return std::make_unique<AssignmentType>(format); };
   }
 
-  static unique_ptr<NameAssignmentFunc>
+  static std::unique_ptr<NameAssignmentFunc>
   createNameAssignmentFunc(const std::string& challengeType, const std::string& format = "");
 
 NDNCERT_PUBLIC_WITH_TESTS_ELSE_PROTECTED:
   std::vector<std::string> m_nameFormat;
 
 private:
-  typedef function<unique_ptr<NameAssignmentFunc>(const std::string&)> FactoryCreateFunc;
+  typedef std::function<std::unique_ptr<NameAssignmentFunc>(const std::string&)> FactoryCreateFunc;
   typedef std::map<std::string, FactoryCreateFunc> CurriedFuncFactory;
 
   static CurriedFuncFactory&
@@ -73,15 +73,15 @@
 };
 
 #define NDNCERT_REGISTER_FUNCFACTORY(C, T)                                        \
-  static class NdnCert##C##FuncFactoryRegistrationClass {                         \
+  static class NdnCert##C##FuncFactoryRegistrationClass                           \
+  {                                                                               \
   public:                                                                         \
     NdnCert##C##FuncFactoryRegistrationClass()                                    \
     {                                                                             \
-      ::ndn::ndncert::NameAssignmentFunc::registerNameAssignmentFunc<C>(T);       \
+      ::ndncert::NameAssignmentFunc::registerNameAssignmentFunc<C>(T);            \
     }                                                                             \
   } g_NdnCert##C##ChallengeRegistrationVariable
 
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_ASSIGNMENT_FUNC_HPP
diff --git a/src/name-assignment/assignment-hash.cpp b/src/name-assignment/assignment-hash.cpp
index f292821..f406619 100644
--- a/src/name-assignment/assignment-hash.cpp
+++ b/src/name-assignment/assignment-hash.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -19,26 +19,27 @@
  */
 
 #include "assignment-hash.hpp"
+
 #include <ndn-cxx/util/sha256.hpp>
 
-namespace ndn {
 namespace ndncert {
 
 NDNCERT_REGISTER_FUNCFACTORY(AssignmentHash, "hash");
 
 AssignmentHash::AssignmentHash(const std::string& format)
   : NameAssignmentFunc(format)
-{}
+{
+}
 
-std::vector<PartialName>
+std::vector<ndn::PartialName>
 AssignmentHash::assignName(const std::multimap<std::string, std::string>& params)
 {
-  std::vector<PartialName> resultList;
+  std::vector<ndn::PartialName> resultList;
   Name result;
   for (const auto& item : m_nameFormat) {
     auto it = params.find(item);
     if (it != params.end()) {
-      util::Sha256 digest;
+      ndn::util::Sha256 digest;
       digest << it->second;
       result.append(digest.toString());
     }
@@ -51,4 +52,3 @@
 }
 
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/name-assignment/assignment-hash.hpp b/src/name-assignment/assignment-hash.hpp
index 83acc28..66d3984 100644
--- a/src/name-assignment/assignment-hash.hpp
+++ b/src/name-assignment/assignment-hash.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,7 +23,6 @@
 
 #include "assignment-func.hpp"
 
-namespace ndn {
 namespace ndncert {
 
 /**
@@ -34,12 +33,10 @@
 public:
   AssignmentHash(const std::string& format = "");
 
-  std::vector<PartialName>
+  std::vector<ndn::PartialName>
   assignName(const std::multimap<std::string, std::string>& params) override;
-
 };
 
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_ASSIGNMENT_HASH_HPP
diff --git a/src/name-assignment/assignment-param.cpp b/src/name-assignment/assignment-param.cpp
index 53022cc..956b3d8 100644
--- a/src/name-assignment/assignment-param.cpp
+++ b/src/name-assignment/assignment-param.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -20,19 +20,19 @@
 
 #include "assignment-param.hpp"
 
-namespace ndn {
 namespace ndncert {
 
 NDNCERT_REGISTER_FUNCFACTORY(AssignmentParam, "param");
 
 AssignmentParam::AssignmentParam(const std::string& format)
   : NameAssignmentFunc(format)
-{}
+{
+}
 
-std::vector<PartialName>
+std::vector<ndn::PartialName>
 AssignmentParam::assignName(const std::multimap<std::string, std::string>& params)
 {
-  std::vector<PartialName> resultList;
+  std::vector<ndn::PartialName> resultList;
   Name result;
   for (const auto& item : m_nameFormat) {
     auto it = std::find_if(params.begin(), params.end(),
@@ -49,4 +49,3 @@
 }
 
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/name-assignment/assignment-param.hpp b/src/name-assignment/assignment-param.hpp
index 52bcb80..fc77d27 100644
--- a/src/name-assignment/assignment-param.hpp
+++ b/src/name-assignment/assignment-param.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,7 +23,6 @@
 
 #include "assignment-func.hpp"
 
-namespace ndn {
 namespace ndncert {
 
 /**
@@ -34,12 +33,10 @@
 public:
   AssignmentParam(const std::string& format = "");
 
-  std::vector<PartialName>
+  std::vector<ndn::PartialName>
   assignName(const std::multimap<std::string, std::string>& params) override;
-
 };
 
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_ASSIGNMENT_PARAM_HPP
diff --git a/src/name-assignment/assignment-random.cpp b/src/name-assignment/assignment-random.cpp
index 284a1f7..3305cae 100644
--- a/src/name-assignment/assignment-random.cpp
+++ b/src/name-assignment/assignment-random.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -19,24 +19,22 @@
  */
 
 #include "assignment-random.hpp"
+
 #include <ndn-cxx/util/random.hpp>
 
-namespace ndn {
 namespace ndncert {
 
 NDNCERT_REGISTER_FUNCFACTORY(AssignmentRandom, "random");
 
 AssignmentRandom::AssignmentRandom(const std::string& format)
   : NameAssignmentFunc(format)
-{}
-
-std::vector<PartialName>
-AssignmentRandom::assignName(const std::multimap<std::string, std::string>& params)
 {
-  std::vector<PartialName> resultList;
-  resultList.emplace_back(to_string(random::generateSecureWord64()));
-  return resultList;
+}
+
+std::vector<ndn::PartialName>
+AssignmentRandom::assignName(const std::multimap<std::string, std::string>&)
+{
+  return {ndn::PartialName(ndn::to_string(ndn::random::generateSecureWord64()))};
 }
 
 } // namespace ndncert
-} // namespace ndn
diff --git a/src/name-assignment/assignment-random.hpp b/src/name-assignment/assignment-random.hpp
index 86f8096..872c784 100644
--- a/src/name-assignment/assignment-random.hpp
+++ b/src/name-assignment/assignment-random.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,7 +23,6 @@
 
 #include "assignment-func.hpp"
 
-namespace ndn {
 namespace ndncert {
 
 /**
@@ -34,11 +33,10 @@
 public:
   AssignmentRandom(const std::string& format = "");
 
-  std::vector<PartialName>
+  std::vector<ndn::PartialName>
   assignName(const std::multimap<std::string, std::string>& params) override;
 };
 
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_ASSIGNMENT_RANDOM_HPP