des-compat.c 5.28 KB
Newer Older
Niels Möller's avatar
Niels Möller committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
/* des-compat.h
 *
 * The des block cipher, libdes/openssl-style interface.
 */

/* nettle, low-level cryptographics library
 *
 * Copyright (C) 2001 Niels Möller
 *  
 * The nettle library is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at your
 * option) any later version.
 * 
 * The nettle library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 * License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with the nettle library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

#include "des-compat.h"

#include "cbc.h"
29
#include "macros.h"
Niels Möller's avatar
Niels Möller committed
30 31 32 33
#include "memxor.h"

#include <string.h>
#include <assert.h>
Niels Möller's avatar
Niels Möller committed
34

35 36 37 38 39 40 41 42
struct des_compat_des3 { struct des_ctx *keys[3]; }; 

typedef void (*cbc_crypt_func)(void *, uint32_t, uint8_t *, const uint8_t *);

static void
des_compat_des3_encrypt(struct des_compat_des3 *ctx,
			uint32_t length, uint8_t *dst, const uint8_t *src)
{
43 44 45
  nettle_des_encrypt(ctx->keys[0], length, dst, src);
  nettle_des_decrypt(ctx->keys[1], length, dst, dst);
  nettle_des_encrypt(ctx->keys[2], length, dst, dst);
46 47 48 49 50
}

static void
des_compat_des3_decrypt(struct des_compat_des3 *ctx,
			uint32_t length, uint8_t *dst, const uint8_t *src)
Niels Möller's avatar
Niels Möller committed
51
{
52 53 54
  nettle_des_decrypt(ctx->keys[2], length, dst, src);
  nettle_des_encrypt(ctx->keys[1], length, dst, dst);
  nettle_des_decrypt(ctx->keys[0], length, dst, dst);
55 56 57
}

void
58 59 60
des_ecb3_encrypt(des_cblock *src, des_cblock *dst,
		 des_key_schedule k1, des_key_schedule k2,
		 des_key_schedule k3, int enc)
61
{
62 63 64 65
  struct des_compat_des3 keys;
  keys.keys[0] = k1;
  keys.keys[1] = k2;
  keys.keys[2] = k3;
66 67

  ((enc == DES_ENCRYPT) ? des_compat_des3_encrypt : des_compat_des3_decrypt)
68
    (&keys, DES_BLOCK_SIZE, *dst, *src);
Niels Möller's avatar
Niels Möller committed
69 70
}

71 72 73 74
uint32_t
des_cbc_cksum(des_cblock *src, des_cblock *dst,
	      long length, des_key_schedule ctx,
	      des_cblock *iv)
Niels Möller's avatar
Niels Möller committed
75 76 77 78 79
{
  /* FIXME: I'm not entirely sure how this function is supposed to
   * work, in particular what it should return, and if iv can be
   * modified. */
  uint8_t block[DES_BLOCK_SIZE];
80
  uint8_t *p;
81 82

  memcpy(block, *iv, DES_BLOCK_SIZE);
83
  
Niels Möller's avatar
Niels Möller committed
84 85
  assert(!(length % DES_BLOCK_SIZE));
  
86
  for (p = *src; length; length -= DES_BLOCK_SIZE, p += DES_BLOCK_SIZE)
Niels Möller's avatar
Niels Möller committed
87
    {
88
      memxor(block, p, DES_BLOCK_SIZE);
89
      nettle_des_encrypt(ctx, DES_BLOCK_SIZE, block, block);
Niels Möller's avatar
Niels Möller committed
90 91
    }
  memcpy(dst, block, DES_BLOCK_SIZE);
92 93

  return LE_READ_UINT32(block + 4);
Niels Möller's avatar
Niels Möller committed
94 95
}

96 97 98 99 100 101 102 103
void
des_ncbc_encrypt(des_cblock *src, des_cblock *dst, long length,
                 des_key_schedule ctx, des_cblock *iv,
                 int enc)
{
  switch (enc)
    {
    case DES_ENCRYPT:
104 105 106
      nettle_cbc_encrypt(ctx, (cbc_crypt_func) des_encrypt,
			 DES_BLOCK_SIZE, *iv,
			 length, *dst, *src);
107 108
      break;
    case DES_DECRYPT:
109 110 111 112
      nettle_cbc_decrypt(ctx,
			 (cbc_crypt_func) des_decrypt,
			 DES_BLOCK_SIZE, *iv,
			 length, *dst, *src);
113 114 115 116 117
      break;
    default:
      abort();
    }
}
Niels Möller's avatar
Niels Möller committed
118 119

void
120 121
des_cbc_encrypt(des_cblock *src, des_cblock *dst, long length,
		des_key_schedule ctx, des_cblock *civ,
Niels Möller's avatar
Niels Möller committed
122 123
		int enc)
{
124
  des_cblock iv;
125 126

  memcpy(iv, civ, DES_BLOCK_SIZE);
Niels Möller's avatar
Niels Möller committed
127

128
  des_ncbc_encrypt(src, dst, length, ctx, &iv, enc);
129
}
Niels Möller's avatar
Niels Möller committed
130

131

Niels Möller's avatar
Niels Möller committed
132
void
133 134
des_ecb_encrypt(des_cblock *src, des_cblock *dst,
		des_key_schedule ctx,
Niels Möller's avatar
Niels Möller committed
135 136
		int enc)
{
137 138
  ((enc == DES_ENCRYPT) ? nettle_des_encrypt : nettle_des_decrypt)
    (ctx, DES_BLOCK_SIZE, *dst, *src);
Niels Möller's avatar
Niels Möller committed
139
}
140

Niels Möller's avatar
Niels Möller committed
141
void
142
des_ede3_cbc_encrypt(des_cblock *src, des_cblock *dst, long length,
143 144 145
		     des_key_schedule k1,
		     des_key_schedule k2,
		     des_key_schedule k3,
146
		     des_cblock *iv,
147 148
		     int enc)
{
149 150 151 152
  struct des_compat_des3 keys;
  keys.keys[0] = k1;
  keys.keys[1] = k2;
  keys.keys[2] = k3;
153

154 155 156
  switch (enc)
    {
    case DES_ENCRYPT:
157 158 159
      nettle_cbc_encrypt(&keys, (cbc_crypt_func) des_compat_des3_encrypt,
			 DES_BLOCK_SIZE, *iv,
			 length, *dst, *src);
160 161
      break;
    case DES_DECRYPT:
162 163 164
      nettle_cbc_decrypt(&keys, (cbc_crypt_func) des_compat_des3_decrypt,
			 DES_BLOCK_SIZE, *iv,
			 length, *dst, *src);
165 166 167 168
      break;
    default:
      abort();
    }
169
}
Niels Möller's avatar
Niels Möller committed
170 171

int
172
des_set_odd_parity(des_cblock *key)
173
{
174
  nettle_des_fix_parity(DES_KEY_SIZE, *key, *key);
Niels Möller's avatar
Niels Möller committed
175 176 177

  /* FIXME: What to return? */
  return 0;
178
}
Niels Möller's avatar
Niels Möller committed
179

180 181 182 183 184 185 186 187 188 189

/* If des_check_key is non-zero, returns
 *
 *   0 for ok, -1 for bad parity, and -2 for weak keys.
 *
 * If des_check_key is zero (the default), always returns zero.
 */

int des_check_key = 0;

Niels Möller's avatar
Niels Möller committed
190
int
191
des_key_sched(des_cblock *key, des_key_schedule ctx)
192
{
193 194 195 196
  if (!des_check_key)
    /* Fix the parity */
    des_set_odd_parity(key);
  
197
  if (nettle_des_set_key(ctx, *key))
Niels Möller's avatar
Niels Möller committed
198 199 200 201
    return 0;
  else switch(ctx->status)
    {
    case DES_BAD_PARITY:
202 203 204 205 206
      if (des_check_key)
        return -1;
      else
        /* We fixed the parity above */
        abort();
Niels Möller's avatar
Niels Möller committed
207
    case DES_WEAK_KEY:
208 209 210 211 212 213 214
      if (des_check_key)
        return -2;

      /* Pretend the key was good */
      ctx->status = DES_OK;
      return 0;
      
Niels Möller's avatar
Niels Möller committed
215 216 217
    default:
      abort();
    }
218
}
Niels Möller's avatar
Niels Möller committed
219 220

int
221
des_is_weak_key(des_cblock *key)
222 223 224
{
  struct des_ctx ctx;

225
  return !nettle_des_set_key(&ctx, *key);
226
}