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   1 /* -*-c-*-
   2  *
   3  * $Id: sha256.h,v 1.3 2004/03/21 22:43:34 mdw Exp $
   4  *
   5  * Implementation of the SHA-256 hash function
   6  *
   7  * (c) 2000 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: sha256.h,v $
  33  * Revision 1.3  2004/03/21 22:43:34  mdw
  34  * New hash variant SHA224.
  35  *
  36  * Revision 1.2  2000/10/15 19:09:20  mdw
  37  * Support HMAC mode for hash functions which need to store more state than
  38  * the hash output size.
  39  *
  40  * Revision 1.1  2000/10/15 17:48:15  mdw
  41  * New SHA variants with longer outputs.
  42  *
  43  */
  44
  45 /*----- Notes on the SHA-256 hash function ----------------------------------*
  46  *
  47  * SHA-1 (Secure Hash Algorithm) was designed by the NSA, for use with the
  48  * Digital Signature Algorithm.  This is an evolution with a larger output
  49  * size, intended to provide security commensurate with 128-bit AES.  At the
  50  * time of writing, SHA-256 is very new, and can't be trusted too far.
  51  */
  52
  53 #ifndef CATACOMB_SHA256_H
  54 #define CATACOMB_SHA256_H
  55
  56 #ifdef __cplusplus
  57   extern "C" {
  58 #endif
  59
  60 /*----- Header files ------------------------------------------------------*/
  61
  62 #include <mLib/bits.h>
  63
  64 #ifndef CATACOMB_GHASH_H
  65 #  include "ghash.h"
  66 #endif
  67
  68 /*----- Magic numbers -----------------------------------------------------*/
  69
  70 #define SHA256_BUFSZ 64
  71 #define SHA256_HASHSZ 32
  72 #define SHA256_STATESZ 32
  73
  74 #define SHA224_BUFSZ 64
  75 #define SHA224_HASHSZ 28
  76 #define SHA224_STATESZ 32
  77
  78 /*----- Data structures ---------------------------------------------------*/
  79
  80 typedef struct sha256_ctx {
  81   uint32 a, b, c, d, e, f, g, h;        /* Chaining variables */
  82   uint32 nl, nh;                        /* Byte count so far */
  83   unsigned off;                         /* Offset into buffer */
  84   octet buf[SHA256_BUFSZ];              /* Accumulation buffer */
  85 } sha256_ctx, sha224_ctx;
  86
  87 /*----- Functions provided ------------------------------------------------*/
  88
  89 /* --- @sha256_compress@, @sha224_compress@ --- *
  90  *
  91  * Arguments:   @sha256_ctx *ctx@ = pointer to context block
  92  *              @const void *sbuf@ = pointer to buffer of appropriate size
  93  *
  94  * Returns:     ---
  95  *
  96  * Use:         SHA-256 compression function.
  97  */
  98
  99 extern void sha256_compress(sha256_ctx */*ctx*/, const void */*sbuf*/);
 100 #define sha224_compress sha256_compress
 101
 102 /* --- @sha256_init@, @sha224_init@ --- *
 103  *
 104  * Arguments:   @sha256_ctx *ctx@ = pointer to context block to initialize
 105  *
 106  * Returns:     ---
 107  *
 108  * Use:         Initializes a context block ready for hashing.
 109  */
 110
 111 extern void sha256_init(sha256_ctx */*ctx*/);
 112 extern void sha224_init(sha256_ctx */*ctx*/);
 113
 114 /* --- @sha256_set@, @sha224_set@ --- *
 115  *
 116  * Arguments:   @sha256_ctx *ctx@ = pointer to context block
 117  *              @const void *buf@ = pointer to state buffer
 118  *              @unsigned long count@ = current count of bytes processed
 119  *
 120  * Returns:     ---
 121  *
 122  * Use:         Initializes a context block from a given state.  This is
 123  *              useful in cases where the initial hash state is meant to be
 124  *              secret, e.g., for NMAC and HMAC support.
 125  */
 126
 127 extern void sha256_set(sha256_ctx */*ctx*/, const void */*buf*/,
 128                        unsigned long /*count*/);
 129 #define sha224_set sha256_set
 130
 131 /* --- @sha256_hash@, @sha224_hash@ --- *
 132  *
 133  * Arguments:   @sha256_ctx *ctx@ = pointer to context block
 134  *              @const void *buf@ = buffer of data to hash
 135  *              @size_t sz@ = size of buffer to hash
 136  *
 137  * Returns:     ---
 138  *
 139  * Use:         Hashes a buffer of data.  The buffer may be of any size and
 140  *              alignment.
 141  */
 142
 143 extern void sha256_hash(sha256_ctx */*ctx*/,
 144                         const void */*buf*/, size_t /*sz*/);
 145 #define sha224_hash sha256_hash
 146
 147 /* --- @sha256_done@, @sha224_done@ --- *
 148  *
 149  * Arguments:   @sha256_ctx *ctx@ = pointer to context block
 150  *              @void *hash@ = pointer to output buffer
 151  *
 152  * Returns:     ---
 153  *
 154  * Use:         Returns the hash of the data read so far.
 155  */
 156
 157 extern void sha256_done(sha256_ctx */*ctx*/, void */*hash*/);
 158 extern void sha224_done(sha256_ctx */*ctx*/, void */*hash*/);
 159
 160 /* --- @sha256_state@, @sha224_state@ --- *
 161  *
 162  * Arguments:   @sha256_ctx *ctx@ = pointer to context
 163  *              @void *state@ = pointer to buffer for current state
 164  *
 165  * Returns:     Number of bytes written to the hash function so far.
 166  *
 167  * Use:         Returns the current state of the hash function such that
 168  *              it can be passed to @sha256_set@.
 169  */
 170
 171 extern unsigned long sha256_state(sha256_ctx */*ctx*/, void */*state*/);
 172 #define sha224_state sha256_state
 173
 174 /*----- Generic hash interface --------------------------------------------*/
 175
 176 extern const gchash sha256;
 177 extern const gchash sha224;
 178
 179 /*----- That's all, folks -------------------------------------------------*/
 180
 181 #ifdef __cplusplus
 182   }
 183 #endif
 184
 185 #endif