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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: desx.c,v 1.2 2004/04/02 01:03:49 mdw Exp $ |
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4 | * |
5 | * Implementation of DESX |
6 | * |
7 | * (c) 2001 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Catacomb. |
13 | * |
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. |
18 | * |
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. |
23 | * |
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, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: desx.c,v $ |
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33 | * Revision 1.2 2004/04/02 01:03:49 mdw |
34 | * Miscellaneous constification. |
35 | * |
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36 | * Revision 1.1 2001/04/03 19:36:50 mdw |
37 | * New block cipher DESX added. |
38 | * |
39 | */ |
40 | |
41 | /*----- Header files ------------------------------------------------------*/ |
42 | |
43 | #include <assert.h> |
44 | #include <stdio.h> |
45 | #include <stdlib.h> |
46 | #include <string.h> |
47 | |
48 | #include <mLib/bits.h> |
49 | |
50 | #include "blkc.h" |
51 | #include "des-base.h" |
52 | #include "des.h" |
53 | #include "desx.h" |
54 | #include "desx-tab.h" |
55 | #include "gcipher.h" |
56 | |
57 | /*----- Tables ------------------------------------------------------------*/ |
58 | |
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59 | static const octet s[256] = DESX_S; |
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60 | |
61 | /*----- Global variables --------------------------------------------------*/ |
62 | |
63 | const octet desx_keysz[] = { KSZ_SET, 7, 8, 15, 16, 23, 24, 0 }; |
64 | |
65 | /*----- Main code ---------------------------------------------------------*/ |
66 | |
67 | /* --- @desx_init@ --- * |
68 | * |
69 | * Arguments: @desx_ctx *k@ = pointer to key block |
70 | * @const void *buf@ = pointer to key buffer |
71 | * @size_t sz@ = size of key material |
72 | * |
73 | * Returns: --- |
74 | * |
75 | * Use: Initializes a DESX key buffer. The key buffer contains, in |
76 | * order, a single-DES key (either 7 or 8 bytes), an optional |
77 | * 8-byte pre-whitening key, and an optional 8-byte |
78 | * port-whitening key. If no whitening keys are specified, the |
79 | * algorithm becomes the same as single-DES. |
80 | */ |
81 | |
82 | static void mangle(octet *b, const octet *p) |
83 | { |
84 | unsigned i; |
85 | |
86 | for (i = 0; i < 8; i++) |
87 | b[i] = *p++ ^ s[b[i] ^ b[(i + 1) & 7u]]; |
88 | } |
89 | |
90 | void desx_init(desx_ctx *k, const void *buf, size_t sz) |
91 | { |
92 | const octet *p = buf, *kk = buf; |
93 | size_t n; |
94 | |
95 | KSZ_ASSERT(desx, sz); |
96 | |
97 | n = sz % 8 == 7 ? 7 : 8; |
98 | des_init(&k->k, p, n); |
99 | p += n; |
100 | sz -= n; |
101 | if (!sz) |
102 | k->prea = k->preb = k->posta = k->postb = 0; |
103 | else { |
104 | const octet *q = p; |
105 | k->prea = LOAD32(q + 0); |
106 | k->preb = LOAD32(q + 4); |
107 | p += 8; |
108 | sz -= 8; |
109 | if (sz) { |
110 | k->posta = LOAD32(p + 0); |
111 | k->postb = LOAD32(p + 4); |
112 | } else { |
113 | octet b[16]; |
114 | |
115 | if (n == 7) { |
116 | |
117 | /* --- Expand 7 bits to 8 bits --- * |
118 | * |
119 | * Cloned and hacked from @des_init@ to set parity. |
120 | */ |
121 | |
122 | uint32 x, y, z; |
123 | x = LOAD32(kk + 0); |
124 | x = (x & 0xfe000000) | ((x & 0x01fffff0) >> 1); |
125 | x = (x & 0xfffe0000) | ((x & 0x0001fff8) >> 1); |
126 | x = (x & 0xfffffe00) | ((x & 0x000001fc) >> 1); |
127 | z = x; z ^= z >> 4; z ^= z >> 2; z ^= z >> 1; |
128 | x |= (z & 0x01010101) ^ 0x01010101; |
129 | |
130 | y = LOAD32(kk + 3) << 1; |
131 | y = (y & 0x000000fe) | ((y & 0x1fffff00) << 1); |
132 | y = (y & 0x0000fefe) | ((y & 0x3fff0000) << 1); |
133 | y = (y & 0x00fefefe) | ((y & 0x7f000000) << 1); |
134 | z = y; z ^= z >> 4; z ^= z >> 2; z ^= z >> 1; |
135 | y |= (z & 0x01010101) ^ 0x01010101; |
136 | |
137 | kk = b + 8; |
138 | STORE32(kk + 0, x); STORE32(kk + 4, y); |
139 | } |
140 | |
141 | memset(b, 0, 8); |
142 | mangle(b, kk); |
143 | mangle(b, q); |
144 | k->posta = LOAD32(b + 0); |
145 | k->postb = LOAD32(b + 4); |
146 | } |
147 | } |
148 | } |
149 | |
150 | /* --- @desx_eblk@, @desx_dblk@ --- * |
151 | * |
152 | * Arguments: @const desx_ctx *k@ = pointer to key block |
153 | * @const uint32 s[2]@ = pointer to source block |
154 | * @uint32 d[2]@ = pointer to destination block |
155 | * |
156 | * Returns: --- |
157 | * |
158 | * Use: Low-level block encryption and decryption. |
159 | */ |
160 | |
161 | void desx_eblk(const desx_ctx *k, const uint32 *s, uint32 *d) |
162 | { |
163 | uint32 x = s[0], y = s[1]; |
164 | x ^= k->prea; y ^= k->preb; |
165 | DES_IP(x, y); |
166 | DES_EBLK(k->k.k, x, y, x, y); |
167 | DES_IPINV(x, y); |
168 | x ^= k->posta; y ^= k->postb; |
169 | d[0] = x, d[1] = y; |
170 | } |
171 | |
172 | void desx_dblk(const desx_ctx *k, const uint32 *s, uint32 *d) |
173 | { |
174 | uint32 x = s[0], y = s[1]; |
175 | x ^= k->posta; y ^= k->postb; |
176 | DES_IP(x, y); |
177 | DES_DBLK(k->k.k, x, y, x, y); |
178 | DES_IPINV(x, y); |
179 | x ^= k->prea; y ^= k->preb; |
180 | d[0] = x, d[1] = y; |
181 | } |
182 | |
183 | BLKC_TEST(DESX, desx) |
184 | |
185 | /*----- That's all, folks -------------------------------------------------*/ |