diff --git a/include/mbedtls/ccm.h b/include/mbedtls/ccm.h
index ef75839..579402f 100644
--- a/include/mbedtls/ccm.h
+++ b/include/mbedtls/ccm.h
@@ -28,6 +28,10 @@
 #define MBEDTLS_ERR_CCM_BAD_INPUT      -0x000D /**< Bad input parameters to function. */
 #define MBEDTLS_ERR_CCM_AUTH_FAILED    -0x000F /**< Authenticated decryption failed. */
 
+#if !defined(MBEDTLS_CCM_ALT)
+// Regular implementation
+//
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -125,6 +129,18 @@
                       const unsigned char *input, unsigned char *output,
                       const unsigned char *tag, size_t tag_len );
 
+#ifdef __cplusplus
+}
+#endif
+
+#else  /* !MBEDTLS_CCM_ALT */
+#include "ccm_alt.h"
+#endif /* !MBEDTLS_CCM_ALT */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
 /**
  * \brief          Checkup routine