diff --git a/ndn-cxx/security/transform/base64-decode.cpp b/ndn-cxx/security/transform/base64-decode.cpp
index 7b731a0..e9a3f08 100644
--- a/ndn-cxx/security/transform/base64-decode.cpp
+++ b/ndn-cxx/security/transform/base64-decode.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2021 Regents of the University of California.
+ * Copyright (c) 2013-2022 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -20,7 +20,9 @@
  */
 
 #include "ndn-cxx/security/transform/base64-decode.hpp"
-#include "ndn-cxx/security/impl/openssl.hpp"
+
+#include <openssl/bio.h>
+#include <openssl/evp.h>
 
 namespace ndn {
 namespace security {
diff --git a/ndn-cxx/security/transform/base64-encode.cpp b/ndn-cxx/security/transform/base64-encode.cpp
index 51f5e50..5383a8f 100644
--- a/ndn-cxx/security/transform/base64-encode.cpp
+++ b/ndn-cxx/security/transform/base64-encode.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2021 Regents of the University of California.
+ * Copyright (c) 2013-2022 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -20,7 +20,9 @@
  */
 
 #include "ndn-cxx/security/transform/base64-encode.hpp"
-#include "ndn-cxx/security/impl/openssl.hpp"
+
+#include <openssl/bio.h>
+#include <openssl/evp.h>
 
 namespace ndn {
 namespace security {
diff --git a/ndn-cxx/security/transform/block-cipher.cpp b/ndn-cxx/security/transform/block-cipher.cpp
index 1857776..bc881f1 100644
--- a/ndn-cxx/security/transform/block-cipher.cpp
+++ b/ndn-cxx/security/transform/block-cipher.cpp
@@ -20,7 +20,9 @@
  */
 
 #include "ndn-cxx/security/transform/block-cipher.hpp"
-#include "ndn-cxx/security/impl/openssl.hpp"
+
+#include <openssl/bio.h>
+#include <openssl/evp.h>
 
 #include <boost/lexical_cast.hpp>
 
diff --git a/ndn-cxx/security/transform/private-key.cpp b/ndn-cxx/security/transform/private-key.cpp
index 831ab8a..53501a9 100644
--- a/ndn-cxx/security/transform/private-key.cpp
+++ b/ndn-cxx/security/transform/private-key.cpp
@@ -37,6 +37,11 @@
 #include <boost/lexical_cast.hpp>
 #include <cstring>
 
+#include <openssl/ec.h>
+#include <openssl/pem.h>
+#include <openssl/rsa.h>
+#include <openssl/x509.h>
+
 #define ENSURE_PRIVATE_KEY_LOADED(key) \
   do { \
     if ((key) == nullptr) \
diff --git a/ndn-cxx/security/transform/public-key.cpp b/ndn-cxx/security/transform/public-key.cpp
index 6427f4d..3291628 100644
--- a/ndn-cxx/security/transform/public-key.cpp
+++ b/ndn-cxx/security/transform/public-key.cpp
@@ -28,6 +28,9 @@
 #include "ndn-cxx/security/impl/openssl-helper.hpp"
 #include "ndn-cxx/encoding/buffer-stream.hpp"
 
+#include <openssl/rsa.h>
+#include <openssl/x509.h>
+
 #define ENSURE_PUBLIC_KEY_LOADED(key) \
   do { \
     if ((key) == nullptr) \