diff --git a/library/nist_kw.c b/library/nist_kw.c
index 317a242..03e8072 100644
--- a/library/nist_kw.c
+++ b/library/nist_kw.c
@@ -39,6 +39,7 @@
 
 #include "mbedtls/nist_kw.h"
 #include "mbedtls/platform_util.h"
+#include "mbedtls/error.h"
 
 #include <stdint.h>
 #include <string.h>
@@ -116,7 +117,7 @@
                             unsigned int keybits,
                             const int is_wrap )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     const mbedtls_cipher_info_t *cipher_info;
 
     cipher_info = mbedtls_cipher_info_from_values( cipher,