diff --git a/include/mbedtls/ctr_drbg.h b/include/mbedtls/ctr_drbg.h
index 3408862..390059c 100644
--- a/include/mbedtls/ctr_drbg.h
+++ b/include/mbedtls/ctr_drbg.h
@@ -33,7 +33,13 @@
  */
 /*
  *  Copyright (C) 2006-2019, Arm Limited (or its affiliates), All Rights Reserved
- *  SPDX-License-Identifier: Apache-2.0
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ *
+ *  This file is provided under the Apache License 2.0, or the
+ *  GNU General Public License v2.0 or later.
+ *
+ *  **********
+ *  Apache License 2.0:
  *
  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
  *  not use this file except in compliance with the License.
@@ -47,6 +53,27 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  *
+ *  **********
+ *
+ *  **********
+ *  GNU General Public License v2.0 or later:
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ *  **********
+ *
  *  This file is part of Mbed TLS (https://tls.mbed.org)
  */