diff --git a/library/hmac_drbg.c b/library/hmac_drbg.c
index 27806f3..d0de5de 100644
--- a/library/hmac_drbg.c
+++ b/library/hmac_drbg.c
@@ -547,7 +547,7 @@
                                         unsigned char *buf, size_t len )
 {
     const unsigned char *p = data;
-    mbedtls_platform_memcpy( buf, p + test_offset, len );
+    memcpy( buf, p + test_offset, len );
     test_offset += len;
     return( 0 );
 }