diff --git a/library/sha512.c b/library/sha512.c
index 97cee07..e8d1b69 100644
--- a/library/sha512.c
+++ b/library/sha512.c
@@ -33,6 +33,7 @@
 #if defined(MBEDTLS_SHA512_C)
 
 #include "mbedtls/sha512.h"
+#include "mbedtls/utils.h"
 
 #if defined(_MSC_VER) || defined(__WATCOMC__)
   #define UL64(x) x##ui64
@@ -56,11 +57,6 @@
 
 #if !defined(MBEDTLS_SHA512_ALT)
 
-/* Implementation that should never be optimized out by the compiler */
-static void mbedtls_zeroize( void *v, size_t n ) {
-    volatile unsigned char *p = v; while( n-- ) *p++ = 0;
-}
-
 /*
  * 64-bit integer manipulation macros (big endian)
  */