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   1 /* -*-c-*-
   2  *
   3  * $Id: sha256.h,v 1.1 2000/10/15 17:48:15 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 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: sha256.h,v $
  33  * Revision 1.1  2000/10/15 17:48:15  mdw
  34  * New SHA variants with longer outputs.
  35  *
  36  */
  37
  38 /*----- Notes on the SHA-256 hash function ----------------------------------*
  39  *
  40  * SHA-1 (Secure Hash Algorithm) was designed by the NSA, for use with the
  41  * Digital Signature Algorithm.  This is an evolution with a larger output
  42  * size, intended to provide security commensurate with 128-bit AES.  At the
  43  * time of writing, SHA-256 is very new, and can't be trusted too far.
  44  */
  45
  46 #ifndef CATACOMB_SHA256_H
  47 #define CATACOMB_SHA256_H
  48
  49 #ifdef __cplusplus
  50   extern "C" {
  51 #endif
  52
  53 /*----- Header files ------------------------------------------------------*/
  54
  55 #include <mLib/bits.h>
  56
  57 #ifndef CATACOMB_GHASH_H
  58 #  include "ghash.h"
  59 #endif
  60
  61 /*----- Magic numbers -----------------------------------------------------*/
  62
  63 #define SHA256_BUFSZ 64
  64 #define SHA256_HASHSZ 32
  65
  66 /*----- Data structures ---------------------------------------------------*/
  67
  68 typedef struct sha256_ctx {
  69   uint32 a, b, c, d, e, f, g, h;        /* Chaining variables */
  70   uint32 nl, nh;                        /* Byte count so far */
  71   unsigned off;                         /* Offset into buffer */
  72   octet buf[SHA256_BUFSZ];              /* Accumulation buffer */
  73 } sha256_ctx;
  74
  75 /*----- Functions provided ------------------------------------------------*/
  76
  77 /* --- @sha256_compress@ --- *
  78  *
  79  * Arguments:   @sha256_ctx *ctx@ = pointer to context block
  80  *              @const void *sbuf@ = pointer to buffer of appropriate size
  81  *
  82  * Returns:     ---
  83  *
  84  * Use:         SHA-256 compression function.
  85  */
  86
  87 extern void sha256_compress(sha256_ctx */*ctx*/, const void */*sbuf*/);
  88
  89 /* --- @sha256_init@ --- *
  90  *
  91  * Arguments:   @sha256_ctx *ctx@ = pointer to context block to initialize
  92  *
  93  * Returns:     ---
  94  *
  95  * Use:         Initializes a context block ready for hashing.
  96  */
  97
  98 extern void sha256_init(sha256_ctx */*ctx*/);
  99
 100 /* --- @sha256_set@ --- *
 101  *
 102  * Arguments:   @sha256_ctx *ctx@ = pointer to context block
 103  *              @const void *buf@ = pointer to state buffer
 104  *              @unsigned long count@ = current count of bytes processed
 105  *
 106  * Returns:     ---
 107  *
 108  * Use:         Initializes a context block from a given state.  This is
 109  *              useful in cases where the initial hash state is meant to be
 110  *              secret, e.g., for NMAC and HMAC support.
 111  */
 112
 113 extern void sha256_set(sha256_ctx */*ctx*/, const void */*buf*/,
 114                        unsigned long /*count*/);
 115
 116 /* --- @sha256_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
 131 /* --- @sha256_done@ --- *
 132  *
 133  * Arguments:   @sha256_ctx *ctx@ = pointer to context block
 134  *              @void *hash@ = pointer to output buffer
 135  *
 136  * Returns:     ---
 137  *
 138  * Use:         Returns the hash of the data read so far.
 139  */
 140
 141 extern void sha256_done(sha256_ctx */*ctx*/, void */*hash*/);
 142
 143 /* --- @sha256_state@ --- *
 144  *
 145  * Arguments:   @sha256_ctx *ctx@ = pointer to context
 146  *              @void *state@ = pointer to buffer for current state
 147  *
 148  * Returns:     Number of bytes written to the hash function so far.
 149  *
 150  * Use:         Returns the current state of the hash function such that
 151  *              it can be passed to @sha256_set@.
 152  */
 153
 154 extern unsigned long sha256_state(sha256_ctx */*ctx*/, void */*state*/);
 155
 156 /*----- Generic hash interface --------------------------------------------*/
 157
 158 extern const gchash sha256;
 159
 160 /*----- That's all, folks -------------------------------------------------*/
 161
 162 #ifdef __cplusplus
 163   }
 164 #endif
 165
 166 #endif