3 * Implementation of DESX
5 * (c) 2001 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of Catacomb.
12 * Catacomb is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Library General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
17 * Catacomb is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU Library General Public License for more details.
22 * You should have received a copy of the GNU Library General Public
23 * License along with Catacomb; if not, write to the Free
24 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
28 /*----- Header files ------------------------------------------------------*/
35 #include <mLib/bits.h>
43 /*----- Tables ------------------------------------------------------------*/
45 extern const octet desx_s
[256];
47 /*----- Global variables --------------------------------------------------*/
49 const octet desx_keysz
[] = { KSZ_SET
, 23, 7, 8, 15, 16, 24, 0 };
51 /*----- Main code ---------------------------------------------------------*/
53 /* --- @desx_init@ --- *
55 * Arguments: @desx_ctx *k@ = pointer to key block
56 * @const void *buf@ = pointer to key buffer
57 * @size_t sz@ = size of key material
61 * Use: Initializes a DESX key buffer. The key buffer contains, in
62 * order, a single-DES key (either 7 or 8 bytes), an optional
63 * 8-byte pre-whitening key, and an optional 8-byte
64 * port-whitening key. If no whitening keys are specified, the
65 * algorithm becomes the same as single-DES.
68 static void mangle(octet
*b
, const octet
*p
)
72 for (i
= 0; i
< 8; i
++)
73 b
[i
] = *p
++ ^ desx_s
[b
[i
] ^ b
[(i
+ 1) & 7u]];
76 void desx_init(desx_ctx
*k
, const void *buf
, size_t sz
)
78 const octet
*p
= buf
, *kk
= buf
;
83 n
= sz
% 8 == 7 ?
7 : 8;
84 des_init(&k
->k
, p
, n
);
88 k
->prea
= k
->preb
= k
->posta
= k
->postb
= 0;
91 k
->prea
= LOAD32(q
+ 0);
92 k
->preb
= LOAD32(q
+ 4);
96 k
->posta
= LOAD32(p
+ 0);
97 k
->postb
= LOAD32(p
+ 4);
102 des_expand(kk
, n
, &x
, &y
);
103 STORE32(b
+ 8, x
); STORE32(b
+ 12, y
);
107 k
->posta
= LOAD32(b
+ 0);
108 k
->postb
= LOAD32(b
+ 4);
113 /* --- @desx_eblk@, @desx_dblk@ --- *
115 * Arguments: @const desx_ctx *k@ = pointer to key block
116 * @const uint32 s[2]@ = pointer to source block
117 * @uint32 d[2]@ = pointer to destination block
121 * Use: Low-level block encryption and decryption.
124 void desx_eblk(const desx_ctx
*k
, const uint32
*s
, uint32
*d
)
126 uint32 x
= s
[0], y
= s
[1];
127 x
^= k
->prea
; y
^= k
->preb
;
129 DES_EBLK(k
->k
.k
, x
, y
, x
, y
);
131 x
^= k
->posta
; y
^= k
->postb
;
135 void desx_dblk(const desx_ctx
*k
, const uint32
*s
, uint32
*d
)
137 uint32 x
= s
[0], y
= s
[1];
138 x
^= k
->posta
; y
^= k
->postb
;
140 DES_DBLK(k
->k
.k
, x
, y
, x
, y
);
142 x
^= k
->prea
; y
^= k
->preb
;
146 BLKC_TEST(DESX
, desx
)
148 /*----- That's all, folks -------------------------------------------------*/