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/* des.c
*
* The des block cipher.
*
* $Id$
*/
/* nettle, low-level cryptographics library
*
* Copyright (C) 2001 Niels Mller
*
* 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
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* the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA.
*/
/* des - fast & portable DES encryption & decryption.
* Copyright (C) 1992 Dana L. How
* Please see the file `descore.README' for the complete copyright notice.
*/
#include "des.h"
#include "desCode.h"
#include <assert.h>
static ENCRYPT(DesSmallFipsEncrypt,TEMPSMALL, LOADFIPS,KEYMAPSMALL,SAVEFIPS)
static DECRYPT(DesSmallFipsDecrypt,TEMPSMALL, LOADFIPS,KEYMAPSMALL,SAVEFIPS)
/* various tables */
uint32_t des_keymap[] = {
#include "keymap.h"
};
static uint8_t rotors[] = {
#include "rotors.h"
};
static char parity[] = {
#include "parity.h"
};
int
des_set_key(struct des_ctx *ctx, const uint8_t *key)
{
register uint32_t n, w;
register char * b0, * b1;
char bits0[56], bits1[56];
uint32_t *method;
uint8_t *k;
/* check for bad parity and weak keys */
b0 = parity;
n = b0[key[0]]; n <<= 4;
n |= b0[key[1]]; n <<= 4;
n |= b0[key[2]]; n <<= 4;
n |= b0[key[3]]; n <<= 4;
n |= b0[key[4]]; n <<= 4;
n |= b0[key[5]]; n <<= 4;
n |= b0[key[6]]; n <<= 4;
n |= b0[key[7]];
w = 0x88888888l;
/* report bad parity in key */
if ( n & w )
{
ctx->status = DES_BAD_PARITY;
return 0;
}
ctx->status = DES_WEAK_KEY;
/* report a weak or semi-weak key */
if ( !((n - (w >> 3)) & w) ) { /* 1 in 10^10 keys passes this test */
if ( n < 0X41415151 ) {
if ( n < 0X31312121 ) {
if ( n < 0X14141515 ) {
/* 01 01 01 01 01 01 01 01 */
if ( n == 0X11111111 ) return 0;
/* 01 1F 01 1F 01 0E 01 0E */
if ( n == 0X13131212 ) return 0;
} else {
/* 01 E0 01 E0 01 F1 01 F1 */
if ( n == 0X14141515 ) return 0;
/* 01 FE 01 FE 01 FE 01 FE */
if ( n == 0X16161616 ) return 0;
}
} else {
if ( n < 0X34342525 ) {
/* 1F 01 1F 01 0E 01 0E 01 */
if ( n == 0X31312121 ) return 0;
/* 1F 1F 1F 1F 0E 0E 0E 0E */ /* ? */
if ( n == 0X33332222 ) return 0;;
} else {
/* 1F E0 1F E0 0E F1 0E F1 */
if ( n == 0X34342525 ) return 0;;
/* 1F FE 1F FE 0E FE 0E FE */
if ( n == 0X36362626 ) return 0;;
}
}
} else {
if ( n < 0X61616161 ) {
if ( n < 0X44445555 ) {
/* E0 01 E0 01 F1 01 F1 01 */
if ( n == 0X41415151 ) return 0;
/* E0 1F E0 1F F1 0E F1 0E */
if ( n == 0X43435252 ) return 0;
} else {
/* E0 E0 E0 E0 F1 F1 F1 F1 */ /* ? */
if ( n == 0X44445555 ) return 0;
/* E0 FE E0 FE F1 FE F1 FE */
if ( n == 0X46465656 ) return 0;
}
} else {
if ( n < 0X64646565 ) {
/* FE 01 FE 01 FE 01 FE 01 */
if ( n == 0X61616161 ) return 0;
/* FE 1F FE 1F FE 0E FE 0E */
if ( n == 0X63636262 ) return 0;
} else {
/* FE E0 FE E0 FE F1 FE F1 */
if ( n == 0X64646565 ) return 0;
/* FE FE FE FE FE FE FE FE */
if ( n == 0X66666666 ) return 0;
}
}
}
}
/* key is ok */
ctx->status = DES_OK;
/* explode the bits */
n = 56;
b0 = bits0;
b1 = bits1;
do {
w = (256 | *key++) << 2;
do {
--n;
b1[n] = 8 & w;
w >>= 1;
b0[n] = 4 & w;
} while ( w >= 16 );
} while ( n );
/* put the bits in the correct places */
n = 16;
k = rotors;
method = ctx->key;
do {
w = (b1[k[ 0 ]] | b0[k[ 1 ]]) << 4;
w |= (b1[k[ 2 ]] | b0[k[ 3 ]]) << 2;
w |= b1[k[ 4 ]] | b0[k[ 5 ]];
w <<= 8;
w |= (b1[k[ 6 ]] | b0[k[ 7 ]]) << 4;
w |= (b1[k[ 8 ]] | b0[k[ 9 ]]) << 2;
w |= b1[k[10 ]] | b0[k[11 ]];
w <<= 8;
w |= (b1[k[12 ]] | b0[k[13 ]]) << 4;
w |= (b1[k[14 ]] | b0[k[15 ]]) << 2;
w |= b1[k[16 ]] | b0[k[17 ]];
w <<= 8;
w |= (b1[k[18 ]] | b0[k[19 ]]) << 4;
w |= (b1[k[20 ]] | b0[k[21 ]]) << 2;
w |= b1[k[22 ]] | b0[k[23 ]];
method[0] = w;
w = (b1[k[ 0+24]] | b0[k[ 1+24]]) << 4;
w |= (b1[k[ 2+24]] | b0[k[ 3+24]]) << 2;
w |= b1[k[ 4+24]] | b0[k[ 5+24]];
w <<= 8;
w |= (b1[k[ 6+24]] | b0[k[ 7+24]]) << 4;
w |= (b1[k[ 8+24]] | b0[k[ 9+24]]) << 2;
w |= b1[k[10+24]] | b0[k[11+24]];
w <<= 8;
w |= (b1[k[12+24]] | b0[k[13+24]]) << 4;
w |= (b1[k[14+24]] | b0[k[15+24]]) << 2;
w |= b1[k[16+24]] | b0[k[17+24]];
w <<= 8;
w |= (b1[k[18+24]] | b0[k[19+24]]) << 4;
w |= (b1[k[20+24]] | b0[k[21+24]]) << 2;
w |= b1[k[22+24]] | b0[k[23+24]];
ROR(w, 4, 28); /* could be eliminated */
method[1] = w;
k += 48;
method += 2;
} while ( --n );
return 1;
}
void
des_encrypt(struct des_ctx *ctx,
unsigned length, uint8_t *dst,
const uint8_t *src)
{
assert(!(length % DES_BLOCK_SIZE));
assert(ctx->status == DES_OK);
while (length)
{
DesSmallFipsEncrypt(dst, ctx->key, src);
length -= DES_BLOCK_SIZE;
src += DES_BLOCK_SIZE;
dst += DES_BLOCK_SIZE;
}
}
void
des_decrypt(struct des_ctx *ctx,
unsigned length, uint8_t *dst,
const uint8_t *src)
{
assert(!(length % DES_BLOCK_SIZE));
assert(ctx->status == DES_OK);