b348397a |
1 | /* -*-c-*- |
b348397a |
2 | * |
3 | * Implementation of DESX |
4 | * |
5 | * (c) 2001 Straylight/Edgeware |
6 | */ |
7 | |
45c0fd36 |
8 | /*----- Licensing notice --------------------------------------------------* |
b348397a |
9 | * |
10 | * This file is part of Catacomb. |
11 | * |
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. |
45c0fd36 |
16 | * |
b348397a |
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. |
45c0fd36 |
21 | * |
b348397a |
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, |
25 | * MA 02111-1307, USA. |
26 | */ |
27 | |
b348397a |
28 | /*----- Header files ------------------------------------------------------*/ |
29 | |
30 | #include <assert.h> |
31 | #include <stdio.h> |
32 | #include <stdlib.h> |
33 | #include <string.h> |
34 | |
35 | #include <mLib/bits.h> |
36 | |
37 | #include "blkc.h" |
38 | #include "des-base.h" |
39 | #include "des.h" |
40 | #include "desx.h" |
b348397a |
41 | #include "gcipher.h" |
42 | |
43 | /*----- Tables ------------------------------------------------------------*/ |
44 | |
e5b61a8d |
45 | extern const octet desx_s[256]; |
b348397a |
46 | |
47 | /*----- Global variables --------------------------------------------------*/ |
48 | |
986527ae |
49 | const octet desx_keysz[] = { KSZ_SET, 23, 7, 8, 15, 16, 24, 0 }; |
b348397a |
50 | |
51 | /*----- Main code ---------------------------------------------------------*/ |
52 | |
53 | /* --- @desx_init@ --- * |
54 | * |
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 |
58 | * |
59 | * Returns: --- |
60 | * |
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 |
eea8ea58 |
64 | * post-whitening key. If no whitening keys are specified, the |
b348397a |
65 | * algorithm becomes the same as single-DES. |
66 | */ |
67 | |
68 | static void mangle(octet *b, const octet *p) |
69 | { |
70 | unsigned i; |
71 | |
72 | for (i = 0; i < 8; i++) |
e5b61a8d |
73 | b[i] = *p++ ^ desx_s[b[i] ^ b[(i + 1) & 7u]]; |
b348397a |
74 | } |
75 | |
76 | void desx_init(desx_ctx *k, const void *buf, size_t sz) |
77 | { |
78 | const octet *p = buf, *kk = buf; |
79 | size_t n; |
80 | |
81 | KSZ_ASSERT(desx, sz); |
82 | |
83 | n = sz % 8 == 7 ? 7 : 8; |
84 | des_init(&k->k, p, n); |
85 | p += n; |
86 | sz -= n; |
87 | if (!sz) |
88 | k->prea = k->preb = k->posta = k->postb = 0; |
89 | else { |
90 | const octet *q = p; |
91 | k->prea = LOAD32(q + 0); |
92 | k->preb = LOAD32(q + 4); |
93 | p += 8; |
94 | sz -= 8; |
95 | if (sz) { |
96 | k->posta = LOAD32(p + 0); |
97 | k->postb = LOAD32(p + 4); |
98 | } else { |
99 | octet b[16]; |
986527ae |
100 | uint32 x, y; |
b348397a |
101 | |
986527ae |
102 | des_expand(kk, n, &x, &y); |
103 | STORE32(b + 8, x); STORE32(b + 12, y); |
b348397a |
104 | memset(b, 0, 8); |
986527ae |
105 | mangle(b, b + 8); |
b348397a |
106 | mangle(b, q); |
107 | k->posta = LOAD32(b + 0); |
45c0fd36 |
108 | k->postb = LOAD32(b + 4); |
b348397a |
109 | } |
110 | } |
111 | } |
112 | |
113 | /* --- @desx_eblk@, @desx_dblk@ --- * |
114 | * |
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 |
118 | * |
119 | * Returns: --- |
120 | * |
121 | * Use: Low-level block encryption and decryption. |
122 | */ |
123 | |
124 | void desx_eblk(const desx_ctx *k, const uint32 *s, uint32 *d) |
125 | { |
126 | uint32 x = s[0], y = s[1]; |
127 | x ^= k->prea; y ^= k->preb; |
128 | DES_IP(x, y); |
129 | DES_EBLK(k->k.k, x, y, x, y); |
130 | DES_IPINV(x, y); |
131 | x ^= k->posta; y ^= k->postb; |
132 | d[0] = x, d[1] = y; |
133 | } |
134 | |
135 | void desx_dblk(const desx_ctx *k, const uint32 *s, uint32 *d) |
136 | { |
137 | uint32 x = s[0], y = s[1]; |
138 | x ^= k->posta; y ^= k->postb; |
139 | DES_IP(x, y); |
140 | DES_DBLK(k->k.k, x, y, x, y); |
141 | DES_IPINV(x, y); |
142 | x ^= k->prea; y ^= k->preb; |
143 | d[0] = x, d[1] = y; |
144 | } |
145 | |
146 | BLKC_TEST(DESX, desx) |
147 | |
148 | /*----- That's all, folks -------------------------------------------------*/ |