diff --git a/include/mbedtls/chacha20.h b/include/mbedtls/chacha20.h
index a6a8cda..441aaa4 100644
--- a/include/mbedtls/chacha20.h
+++ b/include/mbedtls/chacha20.h
@@ -31,6 +31,7 @@
 
 #ifndef MBEDTLS_CHACHA20_H
 #define MBEDTLS_CHACHA20_H
+#include "mbedtls/private_access.h"
 
 #if !defined(MBEDTLS_CONFIG_FILE)
 #include "mbedtls/config.h"
@@ -51,9 +52,9 @@
 
 typedef struct mbedtls_chacha20_context
 {
-    uint32_t state[16];          /*! The state (before round operations). */
-    uint8_t  keystream8[64];     /*! Leftover keystream bytes. */
-    size_t keystream_bytes_used; /*! Number of keystream bytes already used. */
+    uint32_t MBEDTLS_PRIVATE(state)[16];          /*! The state (before round operations). */
+    uint8_t  MBEDTLS_PRIVATE(keystream8)[64];     /*! Leftover keystream bytes. */
+    size_t MBEDTLS_PRIVATE(keystream_bytes_used); /*! Number of keystream bytes already used. */
 }
 mbedtls_chacha20_context;