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