lib/sha256.h

   1 /* Declarations of functions and data types used for SHA256 and SHA224 sum
   2    library functions.
   3    Copyright (C) 2005-2006, 2008-2020 Free Software Foundation, Inc.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation, either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 #ifndef SHA256_H
  19 # define SHA256_H 1
  20
  21 # include <stdio.h>
  22 # include <stdint.h>
  23
  24 # if HAVE_OPENSSL_SHA256
  25 #  include <openssl/sha.h>
  26 # endif
  27
  28 # ifdef __cplusplus
  29 extern "C" {
  30 # endif
  31
  32 enum { SHA224_DIGEST_SIZE = 224 / 8 };
  33 enum { SHA256_DIGEST_SIZE = 256 / 8 };
  34
  35 # if HAVE_OPENSSL_SHA256
  36 #  define GL_OPENSSL_NAME 224
  37 #  include "gl_openssl.h"
  38 #  define GL_OPENSSL_NAME 256
  39 #  include "gl_openssl.h"
  40 # else
  41 /* Structure to save state of computation between the single steps.  */
  42 struct sha256_ctx
  43 {
  44   uint32_t state[8];
  45
  46   uint32_t total[2];
  47   size_t buflen;       /* ≥ 0, ≤ 128 */
  48   uint32_t buffer[32]; /* 128 bytes; the first buflen bytes are in use */
  49 };
  50
  51 /* Initialize structure containing state of computation. */
  52 extern void sha256_init_ctx (struct sha256_ctx *ctx);
  53 extern void sha224_init_ctx (struct sha256_ctx *ctx);
  54
  55 /* Starting with the result of former calls of this function (or the
  56    initialization function update the context for the next LEN bytes
  57    starting at BUFFER.
  58    It is necessary that LEN is a multiple of 64!!! */
  59 extern void sha256_process_block (const void *buffer, size_t len,
  60                                   struct sha256_ctx *ctx);
  61
  62 /* Starting with the result of former calls of this function (or the
  63    initialization function update the context for the next LEN bytes
  64    starting at BUFFER.
  65    It is NOT required that LEN is a multiple of 64.  */
  66 extern void sha256_process_bytes (const void *buffer, size_t len,
  67                                   struct sha256_ctx *ctx);
  68
  69 /* Process the remaining bytes in the buffer and put result from CTX
  70    in first 32 (28) bytes following RESBUF.  The result is always in little
  71    endian byte order, so that a byte-wise output yields to the wanted
  72    ASCII representation of the message digest.  */
  73 extern void *sha256_finish_ctx (struct sha256_ctx *ctx, void *restrict resbuf);
  74 extern void *sha224_finish_ctx (struct sha256_ctx *ctx, void *restrict resbuf);
  75
  76
  77 /* Put result from CTX in first 32 (28) bytes following RESBUF.  The result is
  78    always in little endian byte order, so that a byte-wise output yields
  79    to the wanted ASCII representation of the message digest.  */
  80 extern void *sha256_read_ctx (const struct sha256_ctx *ctx,
  81                               void *restrict resbuf);
  82 extern void *sha224_read_ctx (const struct sha256_ctx *ctx,
  83                               void *restrict resbuf);
  84
  85
  86 /* Compute SHA256 (SHA224) message digest for LEN bytes beginning at BUFFER.
  87    The result is always in little endian byte order, so that a byte-wise
  88    output yields to the wanted ASCII representation of the message
  89    digest.  */
  90 extern void *sha256_buffer (const char *buffer, size_t len,
  91                             void *restrict resblock);
  92 extern void *sha224_buffer (const char *buffer, size_t len,
  93                             void *restrict resblock);
  94
  95 # endif
  96 /* Compute SHA256 (SHA224) message digest for bytes read from STREAM.
  97    STREAM is an open file stream.  Regular files are handled more efficiently.
  98    The contents of STREAM from its current position to its end will be read.
  99    The case that the last operation on STREAM was an 'ungetc' is not supported.
 100    The resulting message digest number will be written into the 32 (28) bytes
 101    beginning at RESBLOCK.  */
 102 extern int sha256_stream (FILE *stream, void *resblock);
 103 extern int sha224_stream (FILE *stream, void *resblock);
 104
 105
 106 # ifdef __cplusplus
 107 }
 108 # endif
 109
 110 #endif
 111
 112 /*
 113  * Hey Emacs!
 114  * Local Variables:
 115  * coding: utf-8
 116  * End:
 117  */