diff --git a/src/detail/ca-profile.cpp b/src/detail/ca-profile.cpp
index 0f1ad01..624ec7a 100644
--- a/src/detail/ca-profile.cpp
+++ b/src/detail/ca-profile.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.
  *
@@ -20,10 +20,11 @@
 
 #include "detail/ca-profile.hpp"
 #include "challenge/challenge-module.hpp"
+
 #include <ndn-cxx/util/io.hpp>
+
 #include <boost/filesystem.hpp>
 
-namespace ndn {
 namespace ndncert {
 
 CaProfile
@@ -79,7 +80,7 @@
   auto certificateStr = json.get(CONFIG_CERTIFICATE, "");
   if (certificateStr != "") {
     std::istringstream ss(certificateStr);
-    profile.cert = io::load<security::Certificate>(ss);
+    profile.cert = ndn::io::load<Certificate>(ss);
   }
   return profile;
 }
@@ -114,11 +115,10 @@
   }
   if (cert != nullptr) {
     std::stringstream ss;
-    io::save(*cert, ss);
+    ndn::io::save(*cert, ss);
     caItem.put("certificate", ss.str());
   }
   return caItem;
 }
 
 } // namespace ndncert
-} // namespace ndn