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       1                 :             : /*
       2                 :             :    Copyright (c) 2021 Fraunhofer AISEC. See the COPYRIGHT
       3                 :             :    file at the top-level directory of this distribution.
       4                 :             : 
       5                 :             :    Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
       6                 :             :    http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
       7                 :             :    <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
       8                 :             :    option. This file may not be copied, modified, or distributed
       9                 :             :    except according to those terms.
      10                 :             : */
      11                 :             : 
      12                 :             : #include <string.h>
      13                 :             : 
      14                 :             : #include "edhoc/buffer_sizes.h"
      15                 :             : 
      16                 :             : #include "edhoc/suites.h"
      17                 :             : #include "edhoc/prk.h"
      18                 :             : #include "edhoc/okm.h"
      19                 :             : 
      20                 :             : #include "common/crypto_wrapper.h"
      21                 :             : #include "common/oscore_edhoc_error.h"
      22                 :             : #include "common/print_util.h"
      23                 :             : #include "common/memcpy_s.h"
      24                 :             : 
      25                 :          12 : enum err prk_derive(bool static_dh_auth, struct suite suite, uint8_t label,
      26                 :             :                     struct byte_array *context, const struct byte_array *prk_in,
      27                 :             :                     const struct byte_array *stat_pk,
      28                 :             :                     const struct byte_array *stat_sk, uint8_t *prk_out)
      29                 :             : {
      30         [ -  + ]:          12 :         if (static_dh_auth) {
      31         [ #  # ]:           0 :                 BYTE_ARRAY_NEW(dh_secret, ECDH_SECRET_SIZE, ECDH_SECRET_SIZE);
      32                 :             : 
      33         [ #  # ]:           0 :                 TRY(shared_secret_derive(suite.edhoc_ecdh, stat_sk, stat_pk,
      34                 :             :                                          dh_secret.ptr));
      35                 :           0 :                 PRINT_ARRAY("dh_secret", dh_secret.ptr, dh_secret.len);
      36                 :             : 
      37   [ #  #  #  # ]:           0 :                 BYTE_ARRAY_NEW(salt, HASH_SIZE, get_hash_len(suite.edhoc_hash));
      38         [ #  # ]:           0 :                 TRY(edhoc_kdf(suite.edhoc_hash, prk_in, label, context, &salt));
      39                 :           0 :                 PRINT_ARRAY("SALT_3e2m or SALT4e3m", salt.ptr, salt.len);
      40                 :             : 
      41         [ #  # ]:           0 :                 TRY(hkdf_extract(suite.edhoc_hash, &salt, &dh_secret, prk_out));
      42                 :             :         } else {
      43                 :             :                 /*it is save to do that since prks have the same size*/
      44                 :          12 :                 memcpy(prk_out, prk_in->ptr, prk_in->len);
      45                 :             :         }
      46                 :          12 :         return ok;
      47                 :             : }