osfmk/corecrypto/cchmac/src/cchmac_final.c

   1 /*
   2  *  cchmac_final.c
   3  *  corecrypto
   4  *
   5  *  Created on 12/07/2010
   6  *
   7  *  Copyright (c) 2010,2011,2015 Apple Inc. All rights reserved.
   8  *
   9  *
  10  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  11  *
  12  * This file contains Original Code and/or Modifications of Original Code
  13  * as defined in and that are subject to the Apple Public Source License
  14  * Version 2.0 (the 'License'). You may not use this file except in
  15  * compliance with the License. The rights granted to you under the License
  16  * may not be used to create, or enable the creation or redistribution of,
  17  * unlawful or unlicensed copies of an Apple operating system, or to
  18  * circumvent, violate, or enable the circumvention or violation of, any
  19  * terms of an Apple operating system software license agreement.
  20  *
  21  * Please obtain a copy of the License at
  22  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  23  *
  24  * The Original Code and all software distributed under the License are
  25  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  26  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  27  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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  29  * Please see the License for the specific language governing rights and
  30  * limitations under the License.
  31  *
  32  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  33  */
  34
  35 #include <corecrypto/ccdigest_priv.h>
  36 #include <corecrypto/cchmac.h>
  37 #include <corecrypto/ccn.h>
  38 #include <corecrypto/cc_priv.h>
  39
  40 void
  41 cchmac_final(const struct ccdigest_info *di, cchmac_ctx_t hc,
  42     unsigned char *mac)
  43 {
  44         // Finalize the inner state of the data being HMAC'd, i.e., H((key \oplus ipad) || m)
  45         ccdigest_final(di, cchmac_digest_ctx(di, hc), cchmac_data(di, hc));
  46
  47         // Set the HMAC output size based on the digest algorithm
  48         cchmac_num(di, hc) = (unsigned int)di->output_size; /* typecast: output size will alwys fit in an unsigned int */
  49         cchmac_nbits(di, hc) = di->block_size * 8;
  50
  51         // Copy the pre-computed compress(key \oplus opad) back to digest state,
  52         // and then run through the digest once more to finish the HMAC
  53         ccdigest_copy_state(di, cchmac_istate32(di, hc), cchmac_ostate32(di, hc));
  54         ccdigest_final(di, cchmac_digest_ctx(di, hc), mac);
  55 }