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   1 /* -*-c-*-
   2  *
   3  * $Id: sha256.h,v 1.4 2004/04/08 01:36:15 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 /*----- Notes on the SHA-256 hash function ----------------------------------*
  31  *
  32  * SHA-1 (Secure Hash Algorithm) was designed by the NSA, for use with the
  33  * Digital Signature Algorithm.  This is an evolution with a larger output
  34  * size, intended to provide security commensurate with 128-bit AES.  At the
  35  * time of writing, SHA-256 is very new, and can't be trusted too far.
  36  */
  37
  38 #ifndef CATACOMB_SHA256_H
  39 #define CATACOMB_SHA256_H
  40
  41 #ifdef __cplusplus
  42   extern "C" {
  43 #endif
  44
  45 /*----- Header files ------------------------------------------------------*/
  46
  47 #include <mLib/bits.h>
  48
  49 #ifndef CATACOMB_GHASH_H
  50 #  include "ghash.h"
  51 #endif
  52
  53 /*----- Magic numbers -----------------------------------------------------*/
  54
  55 #define SHA256_BUFSZ 64
  56 #define SHA256_HASHSZ 32
  57 #define SHA256_STATESZ 32
  58
  59 #define SHA224_BUFSZ 64
  60 #define SHA224_HASHSZ 28
  61 #define SHA224_STATESZ 32
  62
  63 /*----- Data structures ---------------------------------------------------*/
  64
  65 typedef struct sha256_ctx {
  66   uint32 a, b, c, d, e, f, g, h;        /* Chaining variables */
  67   uint32 nl, nh;                        /* Byte count so far */
  68   unsigned off;                         /* Offset into buffer */
  69   octet buf[SHA256_BUFSZ];              /* Accumulation buffer */
  70 } sha256_ctx, sha224_ctx;
  71
  72 /*----- Functions provided ------------------------------------------------*/
  73
  74 /* --- @sha256_compress@, @sha224_compress@ --- *
  75  *
  76  * Arguments:   @sha256_ctx *ctx@ = pointer to context block
  77  *              @const void *sbuf@ = pointer to buffer of appropriate size
  78  *
  79  * Returns:     ---
  80  *
  81  * Use:         SHA-256 compression function.
  82  */
  83
  84 extern void sha256_compress(sha256_ctx */*ctx*/, const void */*sbuf*/);
  85 #define sha224_compress sha256_compress
  86
  87 /* --- @sha256_init@, @sha224_init@ --- *
  88  *
  89  * Arguments:   @sha256_ctx *ctx@ = pointer to context block to initialize
  90  *
  91  * Returns:     ---
  92  *
  93  * Use:         Initializes a context block ready for hashing.
  94  */
  95
  96 extern void sha256_init(sha256_ctx */*ctx*/);
  97 extern void sha224_init(sha256_ctx */*ctx*/);
  98
  99 /* --- @sha256_set@, @sha224_set@ --- *
 100  *
 101  * Arguments:   @sha256_ctx *ctx@ = pointer to context block
 102  *              @const void *buf@ = pointer to state buffer
 103  *              @unsigned long count@ = current count of bytes processed
 104  *
 105  * Returns:     ---
 106  *
 107  * Use:         Initializes a context block from a given state.  This is
 108  *              useful in cases where the initial hash state is meant to be
 109  *              secret, e.g., for NMAC and HMAC support.
 110  */
 111
 112 extern void sha256_set(sha256_ctx */*ctx*/, const void */*buf*/,
 113                        unsigned long /*count*/);
 114 #define sha224_set sha256_set
 115
 116 /* --- @sha256_hash@, @sha224_hash@ --- *
 117  *
 118  * Arguments:   @sha256_ctx *ctx@ = pointer to context block
 119  *              @const void *buf@ = buffer of data to hash
 120  *              @size_t sz@ = size of buffer to hash
 121  *
 122  * Returns:     ---
 123  *
 124  * Use:         Hashes a buffer of data.  The buffer may be of any size and
 125  *              alignment.
 126  */
 127
 128 extern void sha256_hash(sha256_ctx */*ctx*/,
 129                         const void */*buf*/, size_t /*sz*/);
 130 #define sha224_hash sha256_hash
 131
 132 /* --- @sha256_done@, @sha224_done@ --- *
 133  *
 134  * Arguments:   @sha256_ctx *ctx@ = pointer to context block
 135  *              @void *hash@ = pointer to output buffer
 136  *
 137  * Returns:     ---
 138  *
 139  * Use:         Returns the hash of the data read so far.
 140  */
 141
 142 extern void sha256_done(sha256_ctx */*ctx*/, void */*hash*/);
 143 extern void sha224_done(sha256_ctx */*ctx*/, void */*hash*/);
 144
 145 /* --- @sha256_state@, @sha224_state@ --- *
 146  *
 147  * Arguments:   @sha256_ctx *ctx@ = pointer to context
 148  *              @void *state@ = pointer to buffer for current state
 149  *
 150  * Returns:     Number of bytes written to the hash function so far.
 151  *
 152  * Use:         Returns the current state of the hash function such that
 153  *              it can be passed to @sha256_set@.
 154  */
 155
 156 extern unsigned long sha256_state(sha256_ctx */*ctx*/, void */*state*/);
 157 #define sha224_state sha256_state
 158
 159 /*----- Generic hash interface --------------------------------------------*/
 160
 161 extern const gchash sha256;
 162 extern const gchash sha224;
 163
 164 /*----- That's all, folks -------------------------------------------------*/
 165
 166 #ifdef __cplusplus
 167   }
 168 #endif
 169
 170 #endif