diff --git a/programs/pkey/pk_sign.c b/programs/pkey/pk_sign.c
index c1640d6..af52583 100644
--- a/programs/pkey/pk_sign.c
+++ b/programs/pkey/pk_sign.c
@@ -5,6 +5,8 @@
  *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
  */
 
+#define MBEDTLS_DECLARE_PRIVATE_IDENTIFIERS
+
 #include "mbedtls/build_info.h"
 
 #include "mbedtls/platform.h"