text: /*
   * Copyright (C) 2018 Intel Corporation. All rights reserved.
   *
   * SPDX-License-Identifier: BSD-3-Clause
   */
  
  #include <rtl.h>
  
  int hkdf_sha256(uint8_t *out_key, size_t out_len,
  		const uint8_t *secret, size_t secret_len,
  		__unused const uint8_t *salt, __unused size_t salt_len,
  		__unused const uint8_t *info, __unused size_t info_len)
  {
  	/* FIXME: currently, we only support one AaaG/Trusty
  	 * instance, so just simply copy the h/w seed to Trusty.
  	 * In the future, we will choose another crypto library
  	 * to derive multiple seeds in order to support multiple
  	 * AaaG/Trusty instances.
  	 */
  	memcpy_s(out_key, out_len, secret, secret_len);
  
  	return 1;
  }
  