diff --git a/include/mbedtls/rsa.h b/include/mbedtls/rsa.h
index 8aefdb6..0deff00 100644
--- a/include/mbedtls/rsa.h
+++ b/include/mbedtls/rsa.h
@@ -209,6 +209,8 @@
  * Implementation of RSA interface
  */
 
+#if !defined(MBEDTLS_RSA_ALT)
+
 /**
  * \brief          RSA context structure
  */
@@ -252,6 +254,12 @@
 }
 mbedtls_rsa_context;
 
+#else
+
+#include "rsa_alt.h"
+
+#endif /* MBEDTLS_RSA_ALT */
+
 /**
  * \brief          Initialize an RSA context
  *