release/src/router/nettle/des3.c

   1 /* des3.h
   2  *
   3  * Triple DES cipher. Three key encrypt-decrypt-encrypt.
   4  */
   5
   6 /* nettle, low-level cryptographics library
   7  *
   8  * Copyright (C) 2001 Niels Möller
   9  *
  10  * The nettle library is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU Lesser General Public License as published by
  12  * the Free Software Foundation; either version 2.1 of the License, or (at your
  13  * option) any later version.
  14  *
  15  * The nettle library is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  17  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  18  * License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public License
  21  * along with the nettle library; see the file COPYING.LIB.  If not, write to
  22  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  23  * MA 02111-1301, USA.
  24  */
  25
  26 #if HAVE_CONFIG_H
  27 # include "config.h"
  28 #endif
  29
  30 #include "des.h"
  31
  32 /* It's possible to make some more general pipe construction, like the
  33  * lsh/src/cascade.c, but as in practice it's never used for anything
  34  * like triple DES, it's not worth the effort. */
  35
  36 /* Returns 1 for good keys and 0 for weak keys. */
  37 int
  38 des3_set_key(struct des3_ctx *ctx, const uint8_t *key)
  39 {
  40   unsigned i;
  41   int is_good = 1;
  42
  43   for (i = 0; i<3; i++, key += DES_KEY_SIZE)
  44     if (!des_set_key(&ctx->des[i], key))
  45       is_good = 0;
  46
  47   return is_good;
  48 }
  49
  50 void
  51 des3_encrypt(const struct des3_ctx *ctx,
  52              unsigned length, uint8_t *dst,
  53              const uint8_t *src)
  54 {
  55   des_encrypt(&ctx->des[0],
  56               length, dst, src);
  57   des_decrypt(&ctx->des[1],
  58               length, dst, dst);
  59   des_encrypt(&ctx->des[2],
  60               length, dst, dst);
  61 }
  62
  63 void
  64 des3_decrypt(const struct des3_ctx *ctx,
  65              unsigned length, uint8_t *dst,
  66              const uint8_t *src)
  67 {
  68   des_decrypt(&ctx->des[2],
  69               length, dst, src);
  70   des_encrypt(&ctx->des[1],
  71               length, dst, dst);
  72   des_decrypt(&ctx->des[0],
  73               length, dst, dst);
  74 }