git.distorted.org.uk Git - u/mdw/catacomb/blob - sha256.h

   1 /* -*-c-*-
   2  *
   3  * $Id$
   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 #define CATACOMB_SHA224_H
  41
  42 #ifdef __cplusplus
  43   extern "C" {
  44 #endif
  45
  46 /*----- Header files ------------------------------------------------------*/
  47
  48 #include <mLib/bits.h>
  49
  50 #ifndef CATACOMB_GHASH_H
  51 #  include "ghash.h"
  52 #endif
  53
  54 /*----- Magic numbers -----------------------------------------------------*/
  55
  56 #define SHA256_BUFSZ 64
  57 #define SHA256_HASHSZ 32
  58 #define SHA256_STATESZ 32
  59
  60 #define SHA224_BUFSZ 64
  61 #define SHA224_HASHSZ 28
  62 #define SHA224_STATESZ 32
  63
  64 /*----- Data structures ---------------------------------------------------*/
  65
  66 typedef struct sha256_ctx {
  67   uint32 a, b, c, d, e, f, g, h;        /* Chaining variables */
  68   uint32 nl, nh;                        /* Byte count so far */
  69   unsigned off;                         /* Offset into buffer */
  70   octet buf[SHA256_BUFSZ];              /* Accumulation buffer */
  71 } sha256_ctx, sha224_ctx;
  72
  73 /*----- Functions provided ------------------------------------------------*/
  74
  75 /* --- @sha256_compress@, @sha224_compress@ --- *
  76  *
  77  * Arguments:   @sha256_ctx *ctx@ = pointer to context block
  78  *              @const void *sbuf@ = pointer to buffer of appropriate size
  79  *
  80  * Returns:     ---
  81  *
  82  * Use:         SHA-256 compression function.
  83  */
  84
  85 extern void sha256_compress(sha256_ctx */*ctx*/, const void */*sbuf*/);
  86 #define sha224_compress sha256_compress
  87
  88 /* --- @sha256_init@, @sha224_init@ --- *
  89  *
  90  * Arguments:   @sha256_ctx *ctx@ = pointer to context block to initialize
  91  *
  92  * Returns:     ---
  93  *
  94  * Use:         Initializes a context block ready for hashing.
  95  */
  96
  97 extern void sha256_init(sha256_ctx */*ctx*/);
  98 extern void sha224_init(sha256_ctx */*ctx*/);
  99
 100 /* --- @sha256_set@, @sha224_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 #define sha224_set sha256_set
 116
 117 /* --- @sha256_hash@, @sha224_hash@ --- *
 118  *
 119  * Arguments:   @sha256_ctx *ctx@ = pointer to context block
 120  *              @const void *buf@ = buffer of data to hash
 121  *              @size_t sz@ = size of buffer to hash
 122  *
 123  * Returns:     ---
 124  *
 125  * Use:         Hashes a buffer of data.  The buffer may be of any size and
 126  *              alignment.
 127  */
 128
 129 extern void sha256_hash(sha256_ctx */*ctx*/,
 130                         const void */*buf*/, size_t /*sz*/);
 131 #define sha224_hash sha256_hash
 132
 133 /* --- @sha256_done@, @sha224_done@ --- *
 134  *
 135  * Arguments:   @sha256_ctx *ctx@ = pointer to context block
 136  *              @void *hash@ = pointer to output buffer
 137  *
 138  * Returns:     ---
 139  *
 140  * Use:         Returns the hash of the data read so far.
 141  */
 142
 143 extern void sha256_done(sha256_ctx */*ctx*/, void */*hash*/);
 144 extern void sha224_done(sha256_ctx */*ctx*/, void */*hash*/);
 145
 146 /* --- @sha256_state@, @sha224_state@ --- *
 147  *
 148  * Arguments:   @sha256_ctx *ctx@ = pointer to context
 149  *              @void *state@ = pointer to buffer for current state
 150  *
 151  * Returns:     Number of bytes written to the hash function so far.
 152  *
 153  * Use:         Returns the current state of the hash function such that
 154  *              it can be passed to @sha256_set@.
 155  */
 156
 157 extern unsigned long sha256_state(sha256_ctx */*ctx*/, void */*state*/);
 158 #define sha224_state sha256_state
 159
 160 /*----- Generic hash interface --------------------------------------------*/
 161
 162 extern const gchash sha256;
 163 extern const gchash sha224;
 164
 165 /*----- That's all, folks -------------------------------------------------*/
 166
 167 #ifdef __cplusplus
 168   }
 169 #endif
 170
 171 #endif