diff --git a/include/aes.h b/include/aes.h
index b22f0f8..4604a16 100644
--- a/include/aes.h
+++ b/include/aes.h
@@ -17,9 +17,6 @@
  */
 
 
-#include "n2n.h"               // HAVE_OPENSSL_1_1, traceEvent ...
-
-
 #ifndef AES_H
 #define AES_H
 
diff --git a/src/aes.c b/src/aes.c
index 35375bd..3fbea53 100644
--- a/src/aes.c
+++ b/src/aes.c
@@ -17,7 +17,12 @@
  */
 
 
-#include "n2n.h"
+#include <endian.h>  // for be32toh, htobe32
+#include <stdint.h>  // for uint32_t, uint8_t
+#include <stdlib.h>  // for calloc, free
+#include <string.h>  // for memcpy, size_t
+#include "aes.h"     // for AES_BLOCK_SIZE, aes_context_t, AES128_KEY_BYTES
+#include "n2n.h"     // for TRACE_ERROR, traceEvent
 
 
 #if defined (HAVE_OPENSSL_1_1) // openSSL 1.1 ---------------------------------------------------------------------
diff --git a/src/transform_aes.c b/src/transform_aes.c
index ca6eb4f..6e66ada 100644
--- a/src/transform_aes.c
+++ b/src/transform_aes.c
@@ -17,6 +17,7 @@
  */
 
 
+#include "aes.h"             // for AES_BLOCK_SIZE, aes_cbc_decrypt, aes_cbc...
 #include "n2n.h"             // for n2n_trans_op_t, traceEvent, TRACE_ERROR
 #include "pearson.h"         // for pearson_hash_256
 #include "random_numbers.h"  // for n2n_rand