Source/charon/transforms/hmac.h

   1 /**
   2  * @file hmac.h
   3  *
   4  * @brief Implementation of message authentication
   5  * using cryptographic hash functions (HMAC). See RFC2104.
   6  *
   7  */
   8
   9 /*
  10  * Copyright (C) 2005 Jan Hutter, Martin Willi
  11  * Hochschule fuer Technik Rapperswil
  12  *
  13  * This program is free software; you can redistribute it and/or modify it
  14  * under the terms of the GNU General Public License as published by the
  15  * Free Software Foundation; either version 2 of the License, or (at your
  16  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  17  *
  18  * This program is distributed in the hope that it will be useful, but
  19  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  20  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  21  * for more details.
  22  */
  23
  24 #ifndef HMAC_H_
  25 #define HMAC_H_
  26
  27
  28 #include "hashers/hasher.h"
  29
  30
  31 /**
  32  * Object representing a hmac
  33  */
  34 typedef struct hmac_s hmac_t;
  35
  36 struct hmac_s {
  37         /**
  38          * @brief Generate message authentication code.
  39          *
  40          * @param this                  calling hmac
  41          * @param data                  chunk of data to authenticate
  42          * @param [out]buffer   pointer where the generated bytes will be written
  43          * @return
  44          *                                              - SUCCESS in any case
  45          */
  46         status_t (*get_mac) (hmac_t *this, chunk_t data, u_int8_t *buffer);
  47
  48         /**
  49          * @brief Generates message authentication code and
  50          * allocate space for them.
  51          *
  52          * @param this                  calling hmac
  53          * @param data                  chunk of data to authenticate
  54          * @param [out]chunk    chunk which will hold generated bytes
  55          * @return
  56          *                                              - SUCCESS in any case
  57          *                                              - OUT_OF_RES if space could not be allocated
  58          */
  59         status_t (*allocate_mac) (hmac_t *this, chunk_t data, chunk_t *chunk);
  60
  61         /**
  62          * @brief get the block size of this hmac
  63          *
  64          * @param this                  calling hmac
  65          * @return                              block size in bytes
  66          */
  67         size_t (*get_block_size) (hmac_t *this);
  68
  69         /**
  70          * @brief Destroys a hmac object.
  71          *
  72          * @param this  hmac_t object to destroy
  73          * @return
  74          *                              SUCCESS in any case
  75          */
  76         status_t (*destroy) (hmac_t *this);
  77 };
  78
  79 /**
  80  * Creates a new hmac_t object
  81  *
  82  * @param hash_algorithm                hash algorithm to use
  83  * @param key                                   A chunk containing the key
  84  * @return
  85  *                                                              - hmac_t if successfully
  86  *                                                              - NULL if out of ressources or hash not supported
  87  */
  88 hmac_t *hmac_create(hash_algorithm_t hash_algorithm, chunk_t key);
  89
  90 #endif /*HMAC_H_*/