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>
44 /*----- Tables ------------------------------------------------------------*/
46 extern const octet desx_s[256];
48 /*----- Global variables --------------------------------------------------*/
50 const octet desx_keysz[] = { KSZ_SET, 23, 7, 8, 15, 16, 24, 0 };
52 /*----- Main code ---------------------------------------------------------*/
54 /* --- @desx_init@ --- *
56 * Arguments: @desx_ctx *k@ = pointer to key block
57 * @const void *buf@ = pointer to key buffer
58 * @size_t sz@ = size of key material
62 * Use: Initializes a DESX key buffer. The key buffer contains, in
63 * order, a single-DES key (either 7 or 8 bytes), an optional
64 * 8-byte pre-whitening key, and an optional 8-byte
65 * post-whitening key. If no whitening keys are specified, the
66 * algorithm becomes the same as single-DES.
69 static void mangle(octet *b, const octet *p)
73 for (i = 0; i < 8; i++)
74 b[i] = *p++ ^ desx_s[b[i] ^ b[(i + 1) & 7u]];
77 void desx_init(desx_ctx *k, const void *buf, size_t sz)
79 const octet *p = buf, *kk = buf;
84 n = sz % 8 == 7 ? 7 : 8;
85 des_init(&k->k, p, n);
89 k->prea = k->preb = k->posta = k->postb = 0;
92 k->prea = LOAD32(q + 0);
93 k->preb = LOAD32(q + 4);
97 k->posta = LOAD32(p + 0);
98 k->postb = LOAD32(p + 4);
103 des_expand(kk, n, &x, &y);
104 STORE32(b + 8, x); STORE32(b + 12, y);
108 k->posta = LOAD32(b + 0);
109 k->postb = LOAD32(b + 4);
114 /* --- @desx_eblk@, @desx_dblk@ --- *
116 * Arguments: @const desx_ctx *k@ = pointer to key block
117 * @const uint32 s[2]@ = pointer to source block
118 * @uint32 d[2]@ = pointer to destination block
122 * Use: Low-level block encryption and decryption.
125 void desx_eblk(const desx_ctx *k, const uint32 *s, uint32 *d)
128 typedef uint32 regty;
130 uint32 x = s[0], y = s[1];
131 x ^= k->prea; y ^= k->preb;
133 DES_EBLK(k->k.k, x, y, x, y);
135 x ^= k->posta; y ^= k->postb;
141 void desx_dblk(const desx_ctx *k, const uint32 *s, uint32 *d)
144 typedef uint32 regty;
146 uint32 x = s[0], y = s[1];
147 x ^= k->posta; y ^= k->postb;
149 DES_DBLK(k->k.k, x, y, x, y);
151 x ^= k->prea; y ^= k->preb;
157 BLKC_TEST(DESX, desx)
159 /*----- That's all, folks -------------------------------------------------*/