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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: rc5.c,v 1.2 2000/06/17 11:56:00 mdw Exp $ |
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4 | * |
5 | * The RC5-32/12 block cipher |
6 | * |
7 | * (c) 1999 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: rc5.c,v $ |
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33 | * Revision 1.2 2000/06/17 11:56:00 mdw |
34 | * New key size interface. Use secure arena for memory allocation. |
35 | * |
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36 | * Revision 1.1 1999/09/03 08:41:12 mdw |
37 | * Initial import. |
38 | * |
39 | */ |
40 | |
41 | /*----- Header files ------------------------------------------------------*/ |
42 | |
43 | #include <assert.h> |
44 | #include <stdlib.h> |
45 | #include <string.h> |
46 | |
47 | #include <mLib/alloc.h> |
48 | #include <mLib/bits.h> |
49 | |
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50 | #include "arena.h" |
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51 | #include "blkc.h" |
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52 | #include "gcipher.h" |
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53 | #include "rc5.h" |
54 | |
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55 | /*----- Global variables --------------------------------------------------*/ |
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56 | |
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57 | const octet rc5_keysz[] = { KSZ_RANGE, RC5_KEYSZ, 1, 255, 1 }; |
58 | |
59 | /*----- Internal magical constants ----------------------------------------*/ |
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60 | |
61 | #define T ((RC5_ROUNDS + 1) * 2) |
62 | #define P 0xb7e15163 |
63 | #define Q 0x9e3779b9 |
64 | |
65 | /*----- Main code ---------------------------------------------------------*/ |
66 | |
67 | /* --- @rc5_init@ --- * |
68 | * |
69 | * Arguments: @rc5_ctx *k@ = pointer to a key block |
70 | * @const void *sbuf@ = pointer to key material |
71 | * @size_t sz@ = size of the key material |
72 | * |
73 | * Returns: --- |
74 | * |
75 | * Use: Initializes an RC5 key block. |
76 | */ |
77 | |
78 | void rc5_init(rc5_ctx *k, const void *sbuf, size_t sz) |
79 | { |
80 | uint32 *l; |
81 | size_t w; |
82 | |
83 | /* --- Set up the @L@ table --- * |
84 | * |
85 | * This is slightly unfortunately defined. |
86 | */ |
87 | |
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88 | KSZ_ASSERT(rc5, sz); |
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89 | |
90 | { |
91 | int i; |
92 | const octet *p = sbuf; |
93 | |
94 | /* --- Create the buffer --- */ |
95 | |
96 | w = (sz + 3) / 4; |
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97 | l = XS_ALLOC(w * sizeof(uint32)); |
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98 | |
99 | /* --- Extract the key material --- */ |
100 | |
101 | for (i = 0; sz > 3; i++) { |
102 | l[i] = LOAD32_L(p); |
103 | p += 4; |
104 | sz -= 4; |
105 | } |
106 | |
107 | /* --- Fix up the tail end --- */ |
108 | |
109 | if (sz) { |
110 | uint32 x = U8(*p++); |
111 | if (sz > 1) x |= (U8(*p++) << 8); |
112 | if (sz > 2) x |= (U8(*p++) << 16); |
113 | l[i] = x; |
114 | } |
115 | } |
116 | |
117 | /* --- Initialize the @S@ table --- */ |
118 | |
119 | { |
120 | int i; |
121 | |
122 | k->s[0] = P; |
123 | for (i = 1; i < T; i++) |
124 | k->s[i] = k->s[i - 1] + Q; |
125 | } |
126 | |
127 | /* --- Mix in the key --- */ |
128 | |
129 | { |
130 | int m = 3 * (w > T ? w : T); |
131 | int i, j, c; |
132 | uint32 a, b; |
133 | |
134 | for (c = i = j = a = b = 0; c < m; c++) { |
135 | uint32 x; |
136 | |
137 | x = k->s[i] + a + b; |
138 | k->s[i] = a = ROL32(x, 3); |
139 | i++; if (i >= T) i = 0; |
140 | |
141 | x = l[j] + a + b; |
142 | l[j] = b = ROL32(x, a + b); |
143 | j++; if (j >= w) j = 0; |
144 | } |
145 | } |
146 | |
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147 | memset(l, 0, w * sizeof(uint32)); |
148 | XS_FREE(l); |
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149 | } |
150 | |
151 | /* --- @EROUND@, @DROUND@ --- */ |
152 | |
153 | #define EROUND(x, y, k) do { \ |
154 | uint32 _x; \ |
155 | _x = x ^ y; x = ROL32(_x, y) + k[0]; \ |
156 | _x = y ^ x; y = ROL32(_x, x) + k[1]; \ |
157 | k += 2; \ |
158 | } while (0) |
159 | |
160 | #define DROUND(x, y, k) do { \ |
161 | uint32 _x; \ |
162 | k -= 2; \ |
163 | _x = y - k[1]; y = ROR32(_x, x) ^ x; \ |
164 | _x = x - k[0]; x = ROR32(_x, y) ^ y; \ |
165 | } while (0) |
166 | |
167 | /* --- @EBLK@, @DBLK@ --- */ |
168 | |
169 | #define EBLK(a, b, c, d, k) do { \ |
170 | uint32 _l, _r; \ |
171 | const uint32 *_k = (k)->s; \ |
172 | \ |
173 | _l = (a) + _k[0]; \ |
174 | _r = (b) + _k[1]; \ |
175 | _k += 2; \ |
176 | \ |
177 | EROUND(_l, _r, _k); \ |
178 | EROUND(_l, _r, _k); \ |
179 | EROUND(_l, _r, _k); \ |
180 | EROUND(_l, _r, _k); \ |
181 | EROUND(_l, _r, _k); \ |
182 | EROUND(_l, _r, _k); \ |
183 | EROUND(_l, _r, _k); \ |
184 | EROUND(_l, _r, _k); \ |
185 | EROUND(_l, _r, _k); \ |
186 | EROUND(_l, _r, _k); \ |
187 | EROUND(_l, _r, _k); \ |
188 | EROUND(_l, _r, _k); \ |
189 | (c) = _l; \ |
190 | (d) = _r; \ |
191 | } while (0) |
192 | |
193 | #define DBLK(a, b, c, d, k) do { \ |
194 | uint32 _l, _r; \ |
195 | const uint32 *_k = (k)->s + T; \ |
196 | \ |
197 | _l = (a); \ |
198 | _r = (b); \ |
199 | \ |
200 | DROUND(_l, _r, _k); \ |
201 | DROUND(_l, _r, _k); \ |
202 | DROUND(_l, _r, _k); \ |
203 | DROUND(_l, _r, _k); \ |
204 | DROUND(_l, _r, _k); \ |
205 | DROUND(_l, _r, _k); \ |
206 | DROUND(_l, _r, _k); \ |
207 | DROUND(_l, _r, _k); \ |
208 | DROUND(_l, _r, _k); \ |
209 | DROUND(_l, _r, _k); \ |
210 | DROUND(_l, _r, _k); \ |
211 | DROUND(_l, _r, _k); \ |
212 | \ |
213 | _k -= 2; \ |
214 | (d) = _r - _k[1]; \ |
215 | (c) = _l - _k[0]; \ |
216 | } while (0) |
217 | |
218 | /* --- @rc5_eblk@, @rc5_dblk@ --- * |
219 | * |
220 | * Arguments: @const rc5_ctx *k@ = pointer to RC5 context block |
221 | * @const uint32 s[2]@ = pointer to source block |
222 | * @uint32 *d[2]@ = pointer to destination block |
223 | * |
224 | * Returns: --- |
225 | * |
226 | * Use: Low level block encryption and decryption. |
227 | */ |
228 | |
229 | void rc5_eblk(const rc5_ctx *k, const uint32 *s, uint32 *d) |
230 | { |
231 | EBLK(s[0], s[1], d[0], d[1], k); |
232 | } |
233 | |
234 | void rc5_dblk(const rc5_ctx *k, const uint32 *s, uint32 *d) |
235 | { |
236 | DBLK(s[0], s[1], d[0], d[1], k); |
237 | } |
238 | |
239 | /* --- Test rig --- */ |
240 | |
241 | BLKC_TEST(RC5, rc5) |
242 | |
243 | /*----- That's all, folks -------------------------------------------------*/ |