diff --git a/library/md4.c b/library/md4.c
index 828fd42..6a658e3 100644
--- a/library/md4.c
+++ b/library/md4.c
@@ -35,6 +35,7 @@
 
 #include "mbedtls/md4.h"
 #include "mbedtls/platform_util.h"
+#include "mbedtls/error.h"
 
 #include <string.h>
 
@@ -253,7 +254,7 @@
                             const unsigned char *input,
                             size_t ilen )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t fill;
     uint32_t left;
 
@@ -323,7 +324,7 @@
 int mbedtls_md4_finish_ret( mbedtls_md4_context *ctx,
                             unsigned char output[16] )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     uint32_t last, padn;
     uint32_t high, low;
     unsigned char msglen[8];
@@ -371,7 +372,7 @@
                      size_t ilen,
                      unsigned char output[16] )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_md4_context ctx;
 
     mbedtls_md4_init( &ctx );