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/* 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"
#include "macros.h"
#include "memxor.h"
#include <string.h>
#include <assert.h>
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)
{
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);
}
static void
des_compat_des3_decrypt(struct des_compat_des3 *ctx,
uint32_t length, uint8_t *dst, const uint8_t *src)
{
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);
}
void
des_ecb3_encrypt(des_cblock *src, des_cblock *dst,
des_key_schedule k1, des_key_schedule k2,
des_key_schedule k3, int enc)
{
struct des_compat_des3 keys;
keys.keys[0] = k1;
keys.keys[1] = k2;
keys.keys[2] = k3;
((enc == DES_ENCRYPT) ? des_compat_des3_encrypt : des_compat_des3_decrypt)
(&keys, DES_BLOCK_SIZE, *dst, *src);
}
uint32_t
des_cbc_cksum(des_cblock *src, des_cblock *dst,
long length, des_key_schedule ctx,
des_cblock *iv)
{
/* 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];
uint8_t *p;
memcpy(block, *iv, DES_BLOCK_SIZE);
assert(!(length % DES_BLOCK_SIZE));
for (p = *src; length; length -= DES_BLOCK_SIZE, p += DES_BLOCK_SIZE)
{
memxor(block, p, DES_BLOCK_SIZE);
nettle_des_encrypt(ctx, DES_BLOCK_SIZE, block, block);
}
memcpy(dst, block, DES_BLOCK_SIZE);
return LE_READ_UINT32(block + 4);
}
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:
nettle_cbc_encrypt(ctx, (cbc_crypt_func) des_encrypt,
DES_BLOCK_SIZE, *iv,
length, *dst, *src);
break;
case DES_DECRYPT:
nettle_cbc_decrypt(ctx,
(cbc_crypt_func) des_decrypt,
DES_BLOCK_SIZE, *iv,
length, *dst, *src);
break;
default:
abort();
}
}
void
des_cbc_encrypt(des_cblock *src, des_cblock *dst, long length,
des_key_schedule ctx, des_cblock *civ,
int enc)
{
des_cblock iv;
memcpy(iv, civ, DES_BLOCK_SIZE);
des_ncbc_encrypt(src, dst, length, ctx, &iv, enc);
}
void
des_ecb_encrypt(des_cblock *src, des_cblock *dst,
des_key_schedule ctx,
int enc)
{
((enc == DES_ENCRYPT) ? nettle_des_encrypt : nettle_des_decrypt)
(ctx, DES_BLOCK_SIZE, *dst, *src);
}
void
des_ede3_cbc_encrypt(des_cblock *src, des_cblock *dst, long length,
des_key_schedule k1,
des_key_schedule k2,
des_key_schedule k3,
des_cblock *iv,
int enc)
{
struct des_compat_des3 keys;
keys.keys[0] = k1;
keys.keys[1] = k2;
keys.keys[2] = k3;
switch (enc)
{
case DES_ENCRYPT:
nettle_cbc_encrypt(&keys, (cbc_crypt_func) des_compat_des3_encrypt,
DES_BLOCK_SIZE, *iv,
length, *dst, *src);
break;
case DES_DECRYPT:
nettle_cbc_decrypt(&keys, (cbc_crypt_func) des_compat_des3_decrypt,
DES_BLOCK_SIZE, *iv,
length, *dst, *src);
break;
default:
abort();
}
}
int
des_set_odd_parity(des_cblock *key)
{
nettle_des_fix_parity(DES_KEY_SIZE, *key, *key);
/* FIXME: What to return? */
return 0;
}
/* 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;
int
des_key_sched(des_cblock *key, des_key_schedule ctx)
{
if (!des_check_key)
/* Fix the parity */
des_set_odd_parity(key);
if (nettle_des_set_key(ctx, *key))
return 0;
else switch(ctx->status)
{
case DES_BAD_PARITY:
if (des_check_key)
return -1;
else
/* We fixed the parity above */
abort();
case DES_WEAK_KEY:
if (des_check_key)
return -2;
/* Pretend the key was good */
ctx->status = DES_OK;
return 0;
default:
abort();
}
}
int
des_is_weak_key(des_cblock *key)
{
struct des_ctx ctx;
return !nettle_des_set_key(&ctx, *key);
}
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