diff --git a/src/ca-module.cpp b/src/ca-module.cpp
index 0318a05..821372b 100644
--- a/src/ca-module.cpp
+++ b/src/ca-module.cpp
@@ -19,7 +19,7 @@
  */
 
 #include "ca-module.hpp"
-#include "crypto-support/enc-tlv.hpp"
+#include "protocol-detail/enc-tlv.hpp"
 #include "identity-challenge/challenge-module.hpp"
 #include "name-assignments/assignment-funcs.hpp"
 #include "protocol-detail/challenge.hpp"
diff --git a/src/ca-module.hpp b/src/ca-module.hpp
index 64af10a..652a7e4 100644
--- a/src/ca-module.hpp
+++ b/src/ca-module.hpp
@@ -22,7 +22,7 @@
 #define NDNCERT_CA_MODULE_HPP
 
 #include "configuration.hpp"
-#include "crypto-support/crypto-helper.hpp"
+#include "protocol-detail/crypto-helper.hpp"
 #include "ca-storage/ca-storage.hpp"
 
 namespace ndn {
diff --git a/src/crypto-support/crypto-helper.cpp b/src/protocol-detail/crypto-helper.cpp
similarity index 99%
rename from src/crypto-support/crypto-helper.cpp
rename to src/protocol-detail/crypto-helper.cpp
index 286490d..b83d13a 100644
--- a/src/crypto-support/crypto-helper.cpp
+++ b/src/protocol-detail/crypto-helper.cpp
@@ -22,6 +22,8 @@
 #include <openssl/err.h>
 #include <openssl/hmac.h>
 #include <openssl/pem.h>
+#include <openssl/ec.h>
+#include <openssl/evp.h>
 #include <ndn-cxx/encoding/buffer-stream.hpp>
 #include <ndn-cxx/security/transform/base64-decode.hpp>
 #include <ndn-cxx/security/transform/base64-encode.hpp>
diff --git a/src/crypto-support/crypto-helper.hpp b/src/protocol-detail/crypto-helper.hpp
similarity index 98%
rename from src/crypto-support/crypto-helper.hpp
rename to src/protocol-detail/crypto-helper.hpp
index eb4122c..8df3fa0 100644
--- a/src/crypto-support/crypto-helper.hpp
+++ b/src/protocol-detail/crypto-helper.hpp
@@ -22,8 +22,6 @@
 #define NDNCERT_CRYPTO_SUPPORT_CRYPTO_HELPER_HPP
 
 #include "../ndncert-common.hpp"
-#include <openssl/ec.h>
-#include <openssl/evp.h>
 
 namespace ndn {
 namespace ndncert {
diff --git a/src/crypto-support/enc-tlv.cpp b/src/protocol-detail/enc-tlv.cpp
similarity index 100%
rename from src/crypto-support/enc-tlv.cpp
rename to src/protocol-detail/enc-tlv.cpp
diff --git a/src/crypto-support/enc-tlv.hpp b/src/protocol-detail/enc-tlv.hpp
similarity index 100%
rename from src/crypto-support/enc-tlv.hpp
rename to src/protocol-detail/enc-tlv.hpp
diff --git a/src/requester-state.hpp b/src/requester-state.hpp
index 06126c1..f027863 100644
--- a/src/requester-state.hpp
+++ b/src/requester-state.hpp
@@ -22,7 +22,7 @@
 #define NDNCERT_REQUESTER_STATE_HPP
 
 #include "ndncert-common.hpp"
-#include "crypto-support/crypto-helper.hpp"
+#include "protocol-detail/crypto-helper.hpp"
 #include "configuration.hpp"
 
 namespace ndn {
diff --git a/src/requester.cpp b/src/requester.cpp
index c7717a7..358126e 100644
--- a/src/requester.cpp
+++ b/src/requester.cpp
@@ -20,7 +20,7 @@
 
 #include "requester.hpp"
 #include "identity-challenge/challenge-module.hpp"
-#include "crypto-support/enc-tlv.hpp"
+#include "protocol-detail/enc-tlv.hpp"
 #include "protocol-detail/challenge.hpp"
 #include "protocol-detail/error.hpp"
 #include "protocol-detail/info.hpp"
diff --git a/tests/unit-tests/crypto-helper.t.cpp b/tests/unit-tests/crypto-helper.t.cpp
index 50b3e0e..4df1b02 100644
--- a/tests/unit-tests/crypto-helper.t.cpp
+++ b/tests/unit-tests/crypto-helper.t.cpp
@@ -18,7 +18,7 @@
  * See AUTHORS.md for complete list of ndncert authors and contributors.
  */
 
-#include "crypto-support/crypto-helper.hpp"
+#include "protocol-detail/crypto-helper.hpp"
 #include "test-common.hpp"
 
 namespace ndn {
diff --git a/tests/unit-tests/enc-tlv.t.cpp b/tests/unit-tests/enc-tlv.t.cpp
index 444c387..24e4d4b 100644
--- a/tests/unit-tests/enc-tlv.t.cpp
+++ b/tests/unit-tests/enc-tlv.t.cpp
@@ -18,8 +18,8 @@
  * See AUTHORS.md for complete list of ndncert authors and contributors.
  */
 
-#include "crypto-support/crypto-helper.hpp"
-#include "crypto-support/enc-tlv.hpp"
+#include "protocol-detail/crypto-helper.hpp"
+#include "protocol-detail/enc-tlv.hpp"
 #include "test-common.hpp"
 
 namespace ndn {