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1 | /* -*-c-*- |
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2 | * |
3 | * The RC5-32/12 block cipher |
4 | * |
5 | * (c) 1999 Straylight/Edgeware |
6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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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. |
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16 | * |
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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. |
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21 | * |
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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 | |
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28 | /*----- Header files ------------------------------------------------------*/ |
29 | |
30 | #include <assert.h> |
31 | #include <stdlib.h> |
32 | #include <string.h> |
33 | |
34 | #include <mLib/alloc.h> |
35 | #include <mLib/bits.h> |
36 | |
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37 | #include "arena.h" |
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38 | #include "blkc.h" |
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39 | #include "gcipher.h" |
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40 | #include "rc5.h" |
41 | |
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42 | /*----- Global variables --------------------------------------------------*/ |
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43 | |
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44 | const octet rc5_keysz[] = { KSZ_RANGE, RC5_KEYSZ, 1, 255, 1 }; |
45 | |
46 | /*----- Internal magical constants ----------------------------------------*/ |
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47 | |
48 | #define T ((RC5_ROUNDS + 1) * 2) |
49 | #define P 0xb7e15163 |
50 | #define Q 0x9e3779b9 |
51 | |
52 | /*----- Main code ---------------------------------------------------------*/ |
53 | |
54 | /* --- @rc5_init@ --- * |
55 | * |
56 | * Arguments: @rc5_ctx *k@ = pointer to a key block |
57 | * @const void *sbuf@ = pointer to key material |
58 | * @size_t sz@ = size of the key material |
59 | * |
60 | * Returns: --- |
61 | * |
62 | * Use: Initializes an RC5 key block. |
63 | */ |
64 | |
65 | void rc5_init(rc5_ctx *k, const void *sbuf, size_t sz) |
66 | { |
67 | uint32 *l; |
68 | size_t w; |
69 | |
70 | /* --- Set up the @L@ table --- * |
71 | * |
72 | * This is slightly unfortunately defined. |
73 | */ |
74 | |
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75 | KSZ_ASSERT(rc5, sz); |
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76 | |
77 | { |
78 | int i; |
79 | const octet *p = sbuf; |
80 | |
81 | /* --- Create the buffer --- */ |
82 | |
83 | w = (sz + 3) / 4; |
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84 | l = XS_ALLOC(w * sizeof(uint32)); |
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85 | |
86 | /* --- Extract the key material --- */ |
87 | |
88 | for (i = 0; sz > 3; i++) { |
89 | l[i] = LOAD32_L(p); |
90 | p += 4; |
91 | sz -= 4; |
92 | } |
93 | |
94 | /* --- Fix up the tail end --- */ |
95 | |
96 | if (sz) { |
97 | uint32 x = U8(*p++); |
98 | if (sz > 1) x |= (U8(*p++) << 8); |
99 | if (sz > 2) x |= (U8(*p++) << 16); |
100 | l[i] = x; |
101 | } |
102 | } |
103 | |
104 | /* --- Initialize the @S@ table --- */ |
105 | |
106 | { |
107 | int i; |
108 | |
109 | k->s[0] = P; |
110 | for (i = 1; i < T; i++) |
111 | k->s[i] = k->s[i - 1] + Q; |
112 | } |
113 | |
114 | /* --- Mix in the key --- */ |
115 | |
116 | { |
117 | int m = 3 * (w > T ? w : T); |
118 | int i, j, c; |
119 | uint32 a, b; |
120 | |
121 | for (c = i = j = a = b = 0; c < m; c++) { |
122 | uint32 x; |
123 | |
124 | x = k->s[i] + a + b; |
125 | k->s[i] = a = ROL32(x, 3); |
126 | i++; if (i >= T) i = 0; |
127 | |
128 | x = l[j] + a + b; |
129 | l[j] = b = ROL32(x, a + b); |
130 | j++; if (j >= w) j = 0; |
131 | } |
132 | } |
133 | |
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134 | memset(l, 0, w * sizeof(uint32)); |
135 | XS_FREE(l); |
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136 | } |
137 | |
138 | /* --- @EROUND@, @DROUND@ --- */ |
139 | |
140 | #define EROUND(x, y, k) do { \ |
141 | uint32 _x; \ |
142 | _x = x ^ y; x = ROL32(_x, y) + k[0]; \ |
143 | _x = y ^ x; y = ROL32(_x, x) + k[1]; \ |
144 | k += 2; \ |
145 | } while (0) |
146 | |
147 | #define DROUND(x, y, k) do { \ |
148 | uint32 _x; \ |
149 | k -= 2; \ |
150 | _x = y - k[1]; y = ROR32(_x, x) ^ x; \ |
151 | _x = x - k[0]; x = ROR32(_x, y) ^ y; \ |
152 | } while (0) |
153 | |
154 | /* --- @EBLK@, @DBLK@ --- */ |
155 | |
156 | #define EBLK(a, b, c, d, k) do { \ |
157 | uint32 _l, _r; \ |
158 | const uint32 *_k = (k)->s; \ |
159 | \ |
160 | _l = (a) + _k[0]; \ |
161 | _r = (b) + _k[1]; \ |
162 | _k += 2; \ |
163 | \ |
164 | EROUND(_l, _r, _k); \ |
165 | EROUND(_l, _r, _k); \ |
166 | EROUND(_l, _r, _k); \ |
167 | EROUND(_l, _r, _k); \ |
168 | EROUND(_l, _r, _k); \ |
169 | EROUND(_l, _r, _k); \ |
170 | EROUND(_l, _r, _k); \ |
171 | EROUND(_l, _r, _k); \ |
172 | EROUND(_l, _r, _k); \ |
173 | EROUND(_l, _r, _k); \ |
174 | EROUND(_l, _r, _k); \ |
175 | EROUND(_l, _r, _k); \ |
176 | (c) = _l; \ |
177 | (d) = _r; \ |
178 | } while (0) |
179 | |
180 | #define DBLK(a, b, c, d, k) do { \ |
181 | uint32 _l, _r; \ |
182 | const uint32 *_k = (k)->s + T; \ |
183 | \ |
184 | _l = (a); \ |
185 | _r = (b); \ |
186 | \ |
187 | DROUND(_l, _r, _k); \ |
188 | DROUND(_l, _r, _k); \ |
189 | DROUND(_l, _r, _k); \ |
190 | DROUND(_l, _r, _k); \ |
191 | DROUND(_l, _r, _k); \ |
192 | DROUND(_l, _r, _k); \ |
193 | DROUND(_l, _r, _k); \ |
194 | DROUND(_l, _r, _k); \ |
195 | DROUND(_l, _r, _k); \ |
196 | DROUND(_l, _r, _k); \ |
197 | DROUND(_l, _r, _k); \ |
198 | DROUND(_l, _r, _k); \ |
199 | \ |
200 | _k -= 2; \ |
201 | (d) = _r - _k[1]; \ |
202 | (c) = _l - _k[0]; \ |
203 | } while (0) |
204 | |
205 | /* --- @rc5_eblk@, @rc5_dblk@ --- * |
206 | * |
207 | * Arguments: @const rc5_ctx *k@ = pointer to RC5 context block |
208 | * @const uint32 s[2]@ = pointer to source block |
209 | * @uint32 *d[2]@ = pointer to destination block |
210 | * |
211 | * Returns: --- |
212 | * |
213 | * Use: Low level block encryption and decryption. |
214 | */ |
215 | |
216 | void rc5_eblk(const rc5_ctx *k, const uint32 *s, uint32 *d) |
217 | { |
218 | EBLK(s[0], s[1], d[0], d[1], k); |
219 | } |
220 | |
221 | void rc5_dblk(const rc5_ctx *k, const uint32 *s, uint32 *d) |
222 | { |
223 | DBLK(s[0], s[1], d[0], d[1], k); |
224 | } |
225 | |
226 | /* --- Test rig --- */ |
227 | |
228 | BLKC_TEST(RC5, rc5) |
229 | |
230 | /*----- That's all, folks -------------------------------------------------*/ |