3 * $Id: desx.c,v 1.3 2004/04/08 01:36:15 mdw Exp $
5 * Implementation of DESX
7 * (c) 2001 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Catacomb.
14 * Catacomb is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU Library General Public License as
16 * published by the Free Software Foundation; either version 2 of the
17 * License, or (at your option) any later version.
19 * Catacomb is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU Library General Public License for more details.
24 * You should have received a copy of the GNU Library General Public
25 * License along with Catacomb; if not, write to the Free
26 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
30 /*----- Header files ------------------------------------------------------*/
37 #include <mLib/bits.h>
46 /*----- Tables ------------------------------------------------------------*/
48 static const octet s
[256] = DESX_S
;
50 /*----- Global variables --------------------------------------------------*/
52 const octet desx_keysz
[] = { KSZ_SET
, 7, 8, 15, 16, 23, 24, 0 };
54 /*----- Main code ---------------------------------------------------------*/
56 /* --- @desx_init@ --- *
58 * Arguments: @desx_ctx *k@ = pointer to key block
59 * @const void *buf@ = pointer to key buffer
60 * @size_t sz@ = size of key material
64 * Use: Initializes a DESX key buffer. The key buffer contains, in
65 * order, a single-DES key (either 7 or 8 bytes), an optional
66 * 8-byte pre-whitening key, and an optional 8-byte
67 * port-whitening key. If no whitening keys are specified, the
68 * algorithm becomes the same as single-DES.
71 static void mangle(octet
*b
, const octet
*p
)
75 for (i
= 0; i
< 8; i
++)
76 b
[i
] = *p
++ ^ s
[b
[i
] ^ b
[(i
+ 1) & 7u]];
79 void desx_init(desx_ctx
*k
, const void *buf
, size_t sz
)
81 const octet
*p
= buf
, *kk
= buf
;
86 n
= sz
% 8 == 7 ?
7 : 8;
87 des_init(&k
->k
, p
, n
);
91 k
->prea
= k
->preb
= k
->posta
= k
->postb
= 0;
94 k
->prea
= LOAD32(q
+ 0);
95 k
->preb
= LOAD32(q
+ 4);
99 k
->posta
= LOAD32(p
+ 0);
100 k
->postb
= LOAD32(p
+ 4);
106 /* --- Expand 7 bits to 8 bits --- *
108 * Cloned and hacked from @des_init@ to set parity.
113 x
= (x
& 0xfe000000) | ((x
& 0x01fffff0) >> 1);
114 x
= (x
& 0xfffe0000) | ((x
& 0x0001fff8) >> 1);
115 x
= (x
& 0xfffffe00) | ((x
& 0x000001fc) >> 1);
116 z
= x
; z
^= z
>> 4; z
^= z
>> 2; z
^= z
>> 1;
117 x
|= (z
& 0x01010101) ^ 0x01010101;
119 y
= LOAD32(kk
+ 3) << 1;
120 y
= (y
& 0x000000fe) | ((y
& 0x1fffff00) << 1);
121 y
= (y
& 0x0000fefe) | ((y
& 0x3fff0000) << 1);
122 y
= (y
& 0x00fefefe) | ((y
& 0x7f000000) << 1);
123 z
= y
; z
^= z
>> 4; z
^= z
>> 2; z
^= z
>> 1;
124 y
|= (z
& 0x01010101) ^ 0x01010101;
127 STORE32(kk
+ 0, x
); STORE32(kk
+ 4, y
);
133 k
->posta
= LOAD32(b
+ 0);
134 k
->postb
= LOAD32(b
+ 4);
139 /* --- @desx_eblk@, @desx_dblk@ --- *
141 * Arguments: @const desx_ctx *k@ = pointer to key block
142 * @const uint32 s[2]@ = pointer to source block
143 * @uint32 d[2]@ = pointer to destination block
147 * Use: Low-level block encryption and decryption.
150 void desx_eblk(const desx_ctx
*k
, const uint32
*s
, uint32
*d
)
152 uint32 x
= s
[0], y
= s
[1];
153 x
^= k
->prea
; y
^= k
->preb
;
155 DES_EBLK(k
->k
.k
, x
, y
, x
, y
);
157 x
^= k
->posta
; y
^= k
->postb
;
161 void desx_dblk(const desx_ctx
*k
, const uint32
*s
, uint32
*d
)
163 uint32 x
= s
[0], y
= s
[1];
164 x
^= k
->posta
; y
^= k
->postb
;
166 DES_DBLK(k
->k
.k
, x
, y
, x
, y
);
168 x
^= k
->prea
; y
^= k
->preb
;
172 BLKC_TEST(DESX
, desx
)
174 /*----- That's all, folks -------------------------------------------------*/