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

   1 /* -*-c-*-
   2  *
   3  * Implementation of the SHA-256 hash function
   4  *
   5  * (c) 2000 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Notes on the SHA-256 hash function --------------------------------*
  29  *
  30  * SHA-1 (Secure Hash Algorithm) was designed by the NSA, for use with the
  31  * Digital Signature Algorithm.  This is an evolution with a larger output
  32  * size, intended to provide security commensurate with 128-bit AES.  At the
  33  * time of writing, SHA-256 is very new, and can't be trusted too far.
  34  */
  35
  36 #ifndef CATACOMB_SHA256_H
  37 #define CATACOMB_SHA256_H
  38 #define CATACOMB_SHA224_H
  39
  40 #ifdef __cplusplus
  41   extern "C" {
  42 #endif
  43
  44 /*----- Header files ------------------------------------------------------*/
  45
  46 #include <mLib/bits.h>
  47
  48 #ifndef CATACOMB_GHASH_H
  49 #  include "ghash.h"
  50 #endif
  51
  52 /*----- Magic numbers -----------------------------------------------------*/
  53
  54 #define SHA256_BUFSZ 64
  55 #define SHA256_HASHSZ 32
  56 #define SHA256_STATESZ 32
  57
  58 #define SHA224_BUFSZ 64
  59 #define SHA224_HASHSZ 28
  60 #define SHA224_STATESZ 32
  61
  62 /*----- Data structures ---------------------------------------------------*/
  63
  64 typedef struct sha256_ctx {
  65   uint32 a, b, c, d, e, f, g, h;        /* Chaining variables */
  66   uint32 nl, nh;                        /* Byte count so far */
  67   unsigned off;                         /* Offset into buffer */
  68   octet buf[SHA256_BUFSZ];              /* Accumulation buffer */
  69 } sha256_ctx, sha224_ctx;
  70
  71 /*----- Functions provided ------------------------------------------------*/
  72
  73 /* --- @sha256_compress@, @sha224_compress@ --- *
  74  *
  75  * Arguments:   @sha256_ctx *ctx@ = pointer to context block
  76  *              @const void *sbuf@ = pointer to buffer of appropriate size
  77  *
  78  * Returns:     ---
  79  *
  80  * Use:         SHA-256 compression function.
  81  */
  82
  83 extern void sha256_compress(sha256_ctx */*ctx*/, const void */*sbuf*/);
  84 #define sha224_compress sha256_compress
  85
  86 /* --- @sha256_init@, @sha224_init@ --- *
  87  *
  88  * Arguments:   @sha256_ctx *ctx@ = pointer to context block to initialize
  89  *
  90  * Returns:     ---
  91  *
  92  * Use:         Initializes a context block ready for hashing.
  93  */
  94
  95 extern void sha256_init(sha256_ctx */*ctx*/);
  96 extern void sha224_init(sha256_ctx */*ctx*/);
  97
  98 /* --- @sha256_set@, @sha224_set@ --- *
  99  *
 100  * Arguments:   @sha256_ctx *ctx@ = pointer to context block
 101  *              @const void *buf@ = pointer to state buffer
 102  *              @unsigned long count@ = current count of bytes processed
 103  *
 104  * Returns:     ---
 105  *
 106  * Use:         Initializes a context block from a given state.  This is
 107  *              useful in cases where the initial hash state is meant to be
 108  *              secret, e.g., for NMAC and HMAC support.
 109  */
 110
 111 extern void sha256_set(sha256_ctx */*ctx*/, const void */*buf*/,
 112                        unsigned long /*count*/);
 113 #define sha224_set sha256_set
 114
 115 /* --- @sha256_hash@, @sha224_hash@ --- *
 116  *
 117  * Arguments:   @sha256_ctx *ctx@ = pointer to context block
 118  *              @const void *buf@ = buffer of data to hash
 119  *              @size_t sz@ = size of buffer to hash
 120  *
 121  * Returns:     ---
 122  *
 123  * Use:         Hashes a buffer of data.  The buffer may be of any size and
 124  *              alignment.
 125  */
 126
 127 extern void sha256_hash(sha256_ctx */*ctx*/,
 128                         const void */*buf*/, size_t /*sz*/);
 129 #define sha224_hash sha256_hash
 130
 131 /* --- @sha256_done@, @sha224_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 extern void sha224_done(sha256_ctx */*ctx*/, void */*hash*/);
 143
 144 /* --- @sha256_state@, @sha224_state@ --- *
 145  *
 146  * Arguments:   @sha256_ctx *ctx@ = pointer to context
 147  *              @void *state@ = pointer to buffer for current state
 148  *
 149  * Returns:     Number of bytes written to the hash function so far.
 150  *
 151  * Use:         Returns the current state of the hash function such that
 152  *              it can be passed to @sha256_set@.
 153  */
 154
 155 extern unsigned long sha256_state(sha256_ctx */*ctx*/, void */*state*/);
 156 #define sha224_state sha256_state
 157
 158 /*----- Generic hash interface --------------------------------------------*/
 159
 160 extern const gchash sha256;
 161 extern const gchash sha224;
 162
 163 /*----- That's all, folks -------------------------------------------------*/
 164
 165 #ifdef __cplusplus
 166   }
 167 #endif
 168
 169 #endif