diff --git a/library/platform.c b/library/platform.c
index b882b659d..76df7fac1 100644
--- a/library/platform.c
+++ b/library/platform.c
@@ -29,6 +29,14 @@
 
 #include "mbedtls/platform.h"
 
+#if defined(MBEDTLS_ENTROPY_NV_SEED) && \
+    !defined(MBEDTLS_PLATFORM_NO_STD_FUNCTIONS) && defined(MBEDTLS_FS_IO)
+/* Implementation that should never be optimized out by the compiler */
+static void mbedtls_zeroize( void *v, size_t n ) {
+    volatile unsigned char *p = (unsigned char*)v; while( n-- ) *p++ = 0;
+}
+#endif
+
 #if defined(MBEDTLS_PLATFORM_MEMORY)
 #if !defined(MBEDTLS_PLATFORM_STD_CALLOC)
 static void *platform_calloc_uninit( size_t n, size_t size )