src/libstrongswan/crypto/hashers/hasher.h

   1 /*
   2  * Copyright (C) 2005 Jan Hutter
   3  * Copyright (C) 2005-2006 Martin Willi
   4  *
   5  * Hochschule fuer Technik Rapperswil
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the
   9  * Free Software Foundation; either version 2 of the License, or (at your
  10  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  14  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15  * for more details.
  16  */
  17
  18 /**
  19  * @defgroup hasher hasher
  20  * @{ @ingroup crypto
  21  */
  22
  23 #ifndef HASHER_H_
  24 #define HASHER_H_
  25
  26 typedef enum hash_algorithm_t hash_algorithm_t;
  27 typedef struct hasher_t hasher_t;
  28
  29 #include <library.h>
  30
  31 /**
  32  * Algorithms to use for hashing.
  33  */
  34 enum hash_algorithm_t {
  35         /** not specified hash function */
  36         HASH_UNKNOWN            = 0,
  37         /** preferred hash function, general purpose */
  38         HASH_PREFERRED          = 1,
  39         HASH_MD2                        = 2,
  40         HASH_MD5                        = 3,
  41         HASH_SHA1                       = 4,
  42         HASH_SHA256             = 5,
  43         HASH_SHA384             = 6,
  44         HASH_SHA512             = 7,
  45         HASH_MD4                        = 8,
  46 };
  47
  48 #define HASH_SIZE_MD2           16
  49 #define HASH_SIZE_MD4           16
  50 #define HASH_SIZE_MD5           16
  51 #define HASH_SIZE_SHA1          20
  52 #define HASH_SIZE_SHA256        32
  53 #define HASH_SIZE_SHA384        48
  54 #define HASH_SIZE_SHA512        64
  55
  56 /**
  57  * enum names for hash_algorithm_t.
  58  */
  59 extern enum_name_t *hash_algorithm_names;
  60
  61 /**
  62  * Generic interface for all hash functions.
  63  */
  64 struct hasher_t {
  65         /**
  66          * Hash data and write it in the buffer.
  67          *
  68          * If the parameter hash is NULL, no result is written back
  69          * and more data can be appended to already hashed data.
  70          * If not, the result is written back and the hasher is reset.
  71          *
  72          * The hash output parameter must hold at least
  73          * hash_t.get_block_size() bytes.
  74          *
  75          * @param data          data to hash
  76          * @param hash          pointer where the hash will be written
  77          */
  78         void (*get_hash) (hasher_t *this, chunk_t data, u_int8_t *hash);
  79
  80         /**
  81          * Hash data and allocate space for the hash.
  82          *
  83          * If the parameter hash is NULL, no result is written back
  84          * and more data can be appended to already hashed data.
  85          * If not, the result is written back and the hasher is reset.
  86          *
  87          * @param data          chunk with data to hash
  88          * @param hash          chunk which will hold allocated hash
  89          */
  90         void (*allocate_hash) (hasher_t *this, chunk_t data, chunk_t *hash);
  91
  92         /**
  93          * Get the size of the resulting hash.
  94          *
  95          * @return                      hash size in bytes
  96          */
  97         size_t (*get_hash_size) (hasher_t *this);
  98
  99         /**
 100          * Resets the hashers state.
 101          */
 102         void (*reset) (hasher_t *this);
 103
 104         /**
 105          * Destroys a hasher object.
 106          */
 107         void (*destroy) (hasher_t *this);
 108 };
 109
 110 /**
 111  * Conversion of ASN.1 OID to hash algorithm.
 112  *
 113  * @param oid                   ASN.1 OID
 114  * @return                              hash algorithm, HASH_UNKNOWN if OID unsuported
 115  */
 116 hash_algorithm_t hasher_algorithm_from_oid(int oid);
 117
 118 /**
 119  * Conversion of hash algorithm into ASN.1 OID.
 120  *
 121  * @param alg                   hash algorithm
 122  * @return                              ASN.1 OID, or OID_UNKNOW
 123  */
 124 int hasher_algorithm_to_oid(hash_algorithm_t alg);
 125
 126 /**
 127  * Conversion of hash signature algorithm into ASN.1 OID.
 128  *
 129  * @param alg                   hash algorithm
 130  * @return                              ASN.1 OID if, or OID_UNKNOW
 131  */
 132 int hasher_signature_algorithm_to_oid(hash_algorithm_t alg);
 133
 134 #endif /** HASHER_H_ @}*/