diff --git a/library/aes.c b/library/aes.c
index aff0a99..6e86990 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -38,6 +38,7 @@
 #include "mbedtls/aes.h"
 #include "mbedtls/platform.h"
 #include "mbedtls/platform_util.h"
+#include "mbedtls/error.h"
 #if defined(MBEDTLS_PADLOCK_C)
 #include "mbedtls/padlock.h"
 #endif
@@ -766,7 +767,7 @@
                                 const unsigned char *key,
                                 unsigned int keybits)
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     const unsigned char *key1, *key2;
     unsigned int key1bits, key2bits;
 
@@ -791,7 +792,7 @@
                                 const unsigned char *key,
                                 unsigned int keybits)
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     const unsigned char *key1, *key2;
     unsigned int key1bits, key2bits;
 
@@ -1175,7 +1176,7 @@
                            const unsigned char *input,
                            unsigned char *output )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t blocks = length / 16;
     size_t leftover = length % 16;
     unsigned char tweak[16];