diff --git a/library/pkcs5.c b/library/pkcs5.c
index a517778..e551547 100644
--- a/library/pkcs5.c
+++ b/library/pkcs5.c
@@ -231,7 +231,7 @@
     unsigned char *out_p = output;
     unsigned char counter[4];
 
-    memset( counter, 0, 4 );
+    mbedtls_platform_memset( counter, 0, 4 );
     counter[3] = 1;
 
 #if UINT_MAX > 0xFFFFFFFF