diff --git a/ndn-cxx/data.hpp b/ndn-cxx/data.hpp
index 389d244..d15b850 100644
--- a/ndn-cxx/data.hpp
+++ b/ndn-cxx/data.hpp
@@ -24,8 +24,8 @@
 
 #include "ndn-cxx/meta-info.hpp"
 #include "ndn-cxx/name.hpp"
-#include "ndn-cxx/packet-base.hpp"
 #include "ndn-cxx/signature.hpp"
+#include "ndn-cxx/detail/packet-base.hpp"
 #include "ndn-cxx/encoding/block.hpp"
 
 namespace ndn {
diff --git a/ndn-cxx/packet-base.cpp b/ndn-cxx/detail/packet-base.cpp
similarity index 96%
rename from ndn-cxx/packet-base.cpp
rename to ndn-cxx/detail/packet-base.cpp
index dd159a8..8ba7362 100644
--- a/ndn-cxx/packet-base.cpp
+++ b/ndn-cxx/detail/packet-base.cpp
@@ -19,7 +19,7 @@
  * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
  */
 
-#include "ndn-cxx/packet-base.hpp"
+#include "ndn-cxx/detail/packet-base.hpp"
 #include "ndn-cxx/lp/tags.hpp"
 
 namespace ndn {
diff --git a/ndn-cxx/packet-base.hpp b/ndn-cxx/detail/packet-base.hpp
similarity index 90%
rename from ndn-cxx/packet-base.hpp
rename to ndn-cxx/detail/packet-base.hpp
index 6eaf36a..8903fd7 100644
--- a/ndn-cxx/packet-base.hpp
+++ b/ndn-cxx/detail/packet-base.hpp
@@ -19,10 +19,10 @@
  * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
  */
 
-#ifndef NDN_PACKET_BASE_HPP
-#define NDN_PACKET_BASE_HPP
+#ifndef NDN_DETAIL_PACKET_BASE_HPP
+#define NDN_DETAIL_PACKET_BASE_HPP
 
-#include "ndn-cxx/tag-host.hpp"
+#include "ndn-cxx/detail/tag-host.hpp"
 
 namespace ndn {
 
@@ -44,4 +44,4 @@
 
 } // namespace ndn
 
-#endif // NDN_PACKET_BASE_HPP
+#endif // NDN_DETAIL_PACKET_BASE_HPP
diff --git a/ndn-cxx/tag-host.hpp b/ndn-cxx/detail/tag-host.hpp
similarity index 95%
rename from ndn-cxx/tag-host.hpp
rename to ndn-cxx/detail/tag-host.hpp
index df6b9a7..8fecc63 100644
--- a/ndn-cxx/tag-host.hpp
+++ b/ndn-cxx/detail/tag-host.hpp
@@ -19,8 +19,8 @@
  * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
  */
 
-#ifndef NDN_TAG_HOST_HPP
-#define NDN_TAG_HOST_HPP
+#ifndef NDN_DETAIL_TAG_HOST_HPP
+#define NDN_DETAIL_TAG_HOST_HPP
 
 #include "ndn-cxx/detail/common.hpp"
 #include "ndn-cxx/tag.hpp"
@@ -97,4 +97,4 @@
 
 } // namespace ndn
 
-#endif // NDN_TAG_HOST_HPP
+#endif // NDN_DETAIL_TAG_HOST_HPP
diff --git a/ndn-cxx/interest.hpp b/ndn-cxx/interest.hpp
index ffc5841..ad271d0 100644
--- a/ndn-cxx/interest.hpp
+++ b/ndn-cxx/interest.hpp
@@ -24,8 +24,8 @@
 
 #include "ndn-cxx/delegation-list.hpp"
 #include "ndn-cxx/name.hpp"
-#include "ndn-cxx/packet-base.hpp"
 #include "ndn-cxx/selectors.hpp"
+#include "ndn-cxx/detail/packet-base.hpp"
 #include "ndn-cxx/util/time.hpp"
 
 #include <boost/logic/tribool.hpp>
diff --git a/ndn-cxx/lp/nack.hpp b/ndn-cxx/lp/nack.hpp
index db1f920..e08307d 100644
--- a/ndn-cxx/lp/nack.hpp
+++ b/ndn-cxx/lp/nack.hpp
@@ -25,7 +25,7 @@
 #define NDN_CXX_LP_NACK_HPP
 
 #include "ndn-cxx/interest.hpp"
-#include "ndn-cxx/packet-base.hpp"
+#include "ndn-cxx/detail/packet-base.hpp"
 #include "ndn-cxx/lp/nack-header.hpp"
 
 namespace ndn {
diff --git a/ndn-cxx/security/v2/validation-state.hpp b/ndn-cxx/security/v2/validation-state.hpp
index 379382c..4ebf31c 100644
--- a/ndn-cxx/security/v2/validation-state.hpp
+++ b/ndn-cxx/security/v2/validation-state.hpp
@@ -22,7 +22,7 @@
 #ifndef NDN_SECURITY_V2_VALIDATION_STATE_HPP
 #define NDN_SECURITY_V2_VALIDATION_STATE_HPP
 
-#include "ndn-cxx/tag-host.hpp"
+#include "ndn-cxx/detail/tag-host.hpp"
 #include "ndn-cxx/security/v2/validation-callback.hpp"
 #include "ndn-cxx/security/v2/certificate.hpp"
 #include "ndn-cxx/util/signal.hpp"
diff --git a/tests/unit/packet-base.t.cpp b/tests/unit/detail/packet-base.t.cpp
similarity index 94%
rename from tests/unit/packet-base.t.cpp
rename to tests/unit/detail/packet-base.t.cpp
index d541512..41d47db 100644
--- a/tests/unit/packet-base.t.cpp
+++ b/tests/unit/detail/packet-base.t.cpp
@@ -19,7 +19,7 @@
  * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
  */
 
-#include "ndn-cxx/packet-base.hpp"
+#include "ndn-cxx/detail/packet-base.hpp"
 #include "ndn-cxx/interest.hpp"
 #include "ndn-cxx/lp/tags.hpp"
 
@@ -28,6 +28,7 @@
 namespace ndn {
 namespace tests {
 
+BOOST_AUTO_TEST_SUITE(Detail)
 BOOST_AUTO_TEST_SUITE(TestPacketBase)
 
 BOOST_AUTO_TEST_CASE(CongestionMark)
@@ -59,6 +60,7 @@
 }
 
 BOOST_AUTO_TEST_SUITE_END() // TestPacketBase
+BOOST_AUTO_TEST_SUITE_END() // Detail
 
 } // namespace tests
 } // namespace ndn
diff --git a/tests/unit/tag-host.t.cpp b/tests/unit/detail/tag-host.t.cpp
similarity index 95%
rename from tests/unit/tag-host.t.cpp
rename to tests/unit/detail/tag-host.t.cpp
index b9192ed..72caa7e 100644
--- a/tests/unit/tag-host.t.cpp
+++ b/tests/unit/detail/tag-host.t.cpp
@@ -19,7 +19,7 @@
  * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
  */
 
-#include "ndn-cxx/tag-host.hpp"
+#include "ndn-cxx/detail/tag-host.hpp"
 #include "ndn-cxx/data.hpp"
 #include "ndn-cxx/interest.hpp"
 
@@ -30,6 +30,7 @@
 namespace ndn {
 namespace tests {
 
+BOOST_AUTO_TEST_SUITE(Detail)
 BOOST_AUTO_TEST_SUITE(TestTagHost)
 
 class TestTag : public Tag
@@ -81,6 +82,7 @@
 }
 
 BOOST_AUTO_TEST_SUITE_END() // TestTagHost
+BOOST_AUTO_TEST_SUITE_END() // Detail
 
 } // namespace tests
 } // namespace ndn