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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: rijndael.c,v 1.3 2001/05/07 15:44:46 mdw Exp $ |
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4 | * |
5 | * The Rijndael block cipher |
6 | * |
7 | * (c) 2000 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: rijndael.c,v $ |
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33 | * Revision 1.3 2001/05/07 15:44:46 mdw |
34 | * Fix unusual numbers of rounds. Simplify implementation. |
35 | * |
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36 | * Revision 1.2 2000/12/06 20:32:59 mdw |
37 | * Fix round count for weird key sizes. |
38 | * |
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39 | * Revision 1.1 2000/06/17 11:56:07 mdw |
40 | * New cipher. |
41 | * |
42 | */ |
43 | |
44 | /*----- Header files ------------------------------------------------------*/ |
45 | |
46 | #include <assert.h> |
47 | #include <stdio.h> |
48 | |
49 | #include <mLib/bits.h> |
50 | |
51 | #include "blkc.h" |
52 | #include "gcipher.h" |
53 | #include "rijndael.h" |
54 | #include "rijndael-tab.h" |
55 | |
56 | /*----- Global variables --------------------------------------------------*/ |
57 | |
58 | const octet rijndael_keysz[] = { KSZ_RANGE, RIJNDAEL_KEYSZ, 4, 32, 4 }; |
59 | |
60 | /*----- Constant tables ---------------------------------------------------*/ |
61 | |
62 | static const octet S[256] = RIJNDAEL_S, SI[256] = RIJNDAEL_SI; |
63 | static const uint32 T[4][256] = RIJNDAEL_T, TI[4][256] = RIJNDAEL_TI; |
64 | static const uint32 U[4][256] = RIJNDAEL_U; |
65 | static const octet rcon[] = RIJNDAEL_RCON; |
66 | |
67 | /*----- Main code ---------------------------------------------------------*/ |
68 | |
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69 | #define SUB(s, a, b, c, d) \ |
70 | (s[U8((a) >> 0)] << 0 | s[U8((b) >> 8)] << 8 | \ |
71 | s[U8((c) >> 16)] << 16 | s[U8((d) >> 24)] << 24) |
72 | |
73 | #define MIX(t, a, b, c, d) \ |
74 | (t[0][U8((a) >> 0)] ^ t[1][U8((b) >> 8)] ^ \ |
75 | t[2][U8((c) >> 16)] ^ t[3][U8((d) >> 24)]) |
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76 | |
77 | /* --- @rijndael_init@ --- * |
78 | * |
79 | * Arguments: @rijndael_ctx *k@ = pointer to context to initialize |
80 | * @const void *buf@ = pointer to buffer of key material |
81 | * @size_t sz@ = size of the key material |
82 | * |
83 | * Returns: --- |
84 | * |
85 | * Use: Initializes a Rijndael context with a particular key. This |
86 | * implementation of Rijndael doesn't impose any particular |
87 | * limits on the key size except that it must be multiple of 4 |
88 | * bytes long. 256 bits seems sensible, though. |
89 | */ |
90 | |
91 | void rijndael_init(rijndael_ctx *k, const void *buf, size_t sz) |
92 | { |
93 | unsigned nk, nr, nw; |
94 | unsigned i, j, jj; |
95 | const octet *p; |
96 | uint32 ww; |
97 | |
98 | /* --- Sort out the key size --- */ |
99 | |
100 | KSZ_ASSERT(rijndael, sz); |
101 | nk = sz / 4; |
102 | |
103 | /* --- Select the number of rounds --- */ |
104 | |
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105 | nr = nk + 6; |
106 | if (nr < 10) |
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107 | nr = 10; |
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108 | k->nr = nr; |
109 | |
110 | /* --- Fetch the first key words out --- */ |
111 | |
112 | p = buf; |
113 | for (i = 0; i < nk; i++) { |
114 | k->w[i] = LOAD32_L(p); |
115 | p += 4; |
116 | } |
117 | |
118 | /* --- Expand this material to fill the rest of the table --- */ |
119 | |
120 | nw = (nr + 1) * (RIJNDAEL_BLKSZ / 4); |
121 | ww = k->w[i - 1]; |
122 | p = rcon; |
123 | for (; i < nw; i++) { |
124 | uint32 w = k->w[i - nk]; |
125 | if (i % nk == 0) { |
126 | ww = ROR32(ww, 8); |
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127 | w ^= SUB(S, ww, ww, ww, ww) ^ *p++; |
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128 | } else if (nk > 6 && i % nk == 4) |
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129 | w ^= SUB(S, ww, ww, ww, ww); |
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130 | else |
131 | w ^= ww; |
132 | k->w[i] = ww = w; |
133 | } |
134 | |
135 | /* --- Make the decryption keys --- */ |
136 | |
137 | j = nw; |
138 | |
139 | j -= RIJNDAEL_BLKSZ / 4; jj = 0; |
140 | for (i = 0; i < RIJNDAEL_BLKSZ / 4; i++) |
141 | k->wi[i] = k->w[j + jj++]; |
142 | |
143 | for (; i < nw - RIJNDAEL_BLKSZ / 4; i += RIJNDAEL_BLKSZ / 4) { |
144 | j -= RIJNDAEL_BLKSZ / 4; |
145 | for (jj = 0; jj < RIJNDAEL_BLKSZ / 4; jj++) { |
146 | uint32 w = k->w[j + jj]; |
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147 | k->wi[i + jj] = MIX(U, w, w, w, w); |
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148 | } |
149 | } |
150 | |
151 | j -= RIJNDAEL_BLKSZ / 4; jj = 0; |
152 | for (; i < nw; i++) |
153 | k->wi[i] = k->w[j + jj++]; |
154 | } |
155 | |
156 | /* --- @rijndael_eblk@, @rijndael_dblk@ --- * |
157 | * |
158 | * Arguments: @const rijndael_ctx *k@ = pointer to Rijndael context |
159 | * @const uint32 s[4]@ = pointer to source block |
160 | * @uint32 d[4]@ = pointer to destination block |
161 | * |
162 | * Returns: --- |
163 | * |
164 | * Use: Low-level block encryption and decryption. |
165 | */ |
166 | |
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167 | #define DO(what, t, aa, bb, cc, dd, a, b, c, d, w) do { \ |
168 | aa = what(t, a, b, c, d) ^ *w++; \ |
169 | bb = what(t, b, c, d, a) ^ *w++; \ |
170 | cc = what(t, c, d, a, b) ^ *w++; \ |
171 | dd = what(t, d, a, b, c) ^ *w++; \ |
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172 | } while (0) |
173 | |
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174 | #define UNDO(what, t, aa, bb, cc, dd, a, b, c, d, w) do { \ |
175 | aa = what(t, a, d, c, b) ^ *w++; \ |
176 | bb = what(t, b, a, d, c) ^ *w++; \ |
177 | cc = what(t, c, b, a, d) ^ *w++; \ |
178 | dd = what(t, d, c, b, a) ^ *w++; \ |
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179 | } while (0) |
180 | |
181 | void rijndael_eblk(const rijndael_ctx *k, const uint32 *s, uint32 *dst) |
182 | { |
183 | uint32 a = s[0], b = s[1], c = s[2], d = s[3]; |
184 | uint32 aa, bb, cc, dd; |
185 | uint32 *w = k->w; |
186 | |
187 | a ^= *w++; b ^= *w++; c ^= *w++; d ^= *w++; |
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188 | aa = a; bb = b; cc = c; dd = d; |
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189 | |
190 | switch (k->nr) { |
191 | case 14: |
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192 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); |
193 | case 13: |
194 | DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w); |
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195 | case 12: |
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196 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); |
197 | case 11: |
198 | DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w); |
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199 | case 10: |
200 | default: |
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201 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); |
202 | DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w); |
203 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); |
204 | DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w); |
205 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); |
206 | DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w); |
207 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); |
208 | DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w); |
209 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); |
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210 | } |
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211 | DO(SUB, S, a, b, c, d, aa, bb, cc, dd, w); |
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212 | |
213 | dst[0] = a; dst[1] = b; dst[2] = c; dst[3] = d; |
214 | } |
215 | |
216 | void rijndael_dblk(const rijndael_ctx *k, const uint32 *s, uint32 *dst) |
217 | { |
218 | uint32 a = s[0], b = s[1], c = s[2], d = s[3]; |
219 | uint32 aa, bb, cc, dd; |
220 | uint32 *w = k->wi; |
221 | |
222 | a ^= *w++; b ^= *w++; c ^= *w++; d ^= *w++; |
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223 | aa = a; bb = b; cc = c; dd = d; |
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224 | |
225 | switch (k->nr) { |
226 | case 14: |
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227 | UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); |
228 | case 13: |
229 | UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w); |
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230 | case 12: |
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231 | UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); |
232 | case 11: |
233 | UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w); |
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234 | case 10: |
235 | default: |
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236 | UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); |
237 | UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w); |
238 | UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); |
239 | UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w); |
240 | UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); |
241 | UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w); |
242 | UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); |
243 | UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w); |
244 | UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); |
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245 | } |
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246 | UNDO(SUB, SI, a, b, c, d, aa, bb, cc, dd, w); |
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247 | |
248 | dst[0] = a; dst[1] = b; dst[2] = c; dst[3] = d; |
249 | } |
250 | |
251 | BLKC_TEST(RIJNDAEL, rijndael) |
252 | |
253 | /*----- That's all, folks -------------------------------------------------*/ |