diff --git a/library/pem.c b/library/pem.c
index 13f9208..527c5f4 100644
--- a/library/pem.c
+++ b/library/pem.c
@@ -33,6 +33,7 @@
 #include "mbedtls/aes.h"
 #include "mbedtls/md5.h"
 #include "mbedtls/cipher.h"
+#include "mbedtls/utils.h"
 
 #include <string.h>
 
@@ -45,11 +46,6 @@
 #endif
 
 #if defined(MBEDTLS_PEM_PARSE_C)
-/* 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;
-}
-
 void mbedtls_pem_init( mbedtls_pem_context *ctx )
 {
     memset( ctx, 0, sizeof( mbedtls_pem_context ) );