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1 | /* -*-c-*- |
2 | * |
b817bfc6 |
3 | * $Id: safer.c,v 1.2 2004/04/08 01:36:15 mdw Exp $ |
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4 | * |
5 | * The SAFER block cipher |
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 | |
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30 | /*----- Header files ------------------------------------------------------*/ |
31 | |
32 | #include <assert.h> |
33 | #include <stdio.h> |
34 | |
35 | #include <mLib/bits.h> |
36 | |
37 | #include "blkc.h" |
38 | #include "gcipher.h" |
39 | #include "paranoia.h" |
40 | #include "safer.h" |
41 | #include "safer-tab.h" |
42 | |
43 | /*----- Global variables --------------------------------------------------*/ |
44 | |
45 | const octet safer_keysz[] = { KSZ_SET, 8, 16, 0 }; |
46 | |
47 | /*----- Important tables --------------------------------------------------*/ |
48 | |
49 | static const octet s[265] = SAFER_S, si[256] = SAFER_SI; |
50 | |
51 | /*----- Main code ---------------------------------------------------------*/ |
52 | |
53 | /* --- @safer_setup@ --- * |
54 | * |
55 | * Arguments: @safer_ctx *k@ = pointer to context to initialize |
56 | * @unsigned r@ = number of rounds wanted |
57 | * @unsigned f@ = various other flags |
58 | * @const void *buf@ = pointer to key material |
59 | * @size_t sz@ = size of key material in bytes |
60 | * |
61 | * Returns: --- |
62 | * |
63 | * Use: Initializes an SAFER expanded key. A default number of |
64 | * rounds is chosen, based on the key length. |
65 | */ |
66 | |
67 | struct ksched { |
68 | unsigned i; |
69 | octet x[9]; |
70 | }; |
71 | |
72 | static void init(struct ksched *t, const octet *k) |
73 | { |
74 | memcpy(t->x, k, 8); |
75 | t->i = 1; |
76 | } |
77 | |
78 | static void init_sk(struct ksched *t, const octet *k) |
79 | { |
80 | unsigned i; |
81 | octet x; |
82 | memcpy(t->x, k, 8); |
83 | for (x = 0, i = 0; i < 8; x ^= k[i++]) |
84 | ; |
85 | t->x[8] = x; |
86 | t->i = 1; |
87 | } |
88 | |
89 | static void next(struct ksched *t, octet *k) |
90 | { |
91 | unsigned i; |
92 | if (k) { |
93 | memcpy(k, t->x, 8); |
94 | if (t->i > 1) { |
95 | for (i = 0; i < 8; i++) |
96 | k[i] += s[s[U8(9*t->i + i + 1)]]; |
97 | } |
98 | } |
99 | for (i = 0; i < 8; i++) |
100 | t->x[i] = ROL8(t->x[i], 3); |
101 | t->i++; |
102 | } |
103 | |
104 | static void next_sk(struct ksched *t, octet *k) |
105 | { |
106 | unsigned i; |
107 | i = (t->i - 1)%9; |
108 | if (k) { |
109 | if (i < 2) |
110 | memcpy(k, t->x + i, 8); |
111 | else { |
112 | memcpy(k, t->x + i, 9 - i); |
113 | memcpy(k + 9 - i, t->x, i - 1); |
114 | } |
115 | if (t->i > 1) { |
116 | for (i = 0; i < 8; i++) |
117 | k[i] += s[s[U8(9*t->i + i + 1)]]; |
118 | } |
119 | } |
120 | for (i = 0; i < 9; i++) |
121 | t->x[i] = ROL8(t->x[i], 3); |
122 | t->i++; |
123 | } |
124 | |
125 | void safer_setup(safer_ctx *k, unsigned r, unsigned f, |
126 | const void *buf, size_t sz) |
127 | { |
128 | struct ksched ka, kb; |
129 | void (*in)(struct ksched *, const octet *); |
130 | void (*nx)(struct ksched *, octet *); |
131 | octet *kk; |
132 | |
133 | assert(r <= SAFER_MAXROUNDS); |
134 | KSZ_ASSERT(safer, sz); |
135 | |
136 | if (f & SAFER_SK) { |
137 | in = init_sk; |
138 | nx = next_sk; |
139 | } else { |
140 | in = init; |
141 | nx = next; |
142 | } |
143 | |
144 | in(&kb, buf); |
145 | in(&ka, sz == 8 ? buf : (const octet *)buf + 8); |
146 | |
147 | k->r = r; |
148 | kk = k->k; |
149 | while (r) { |
150 | nx(&ka, kk); nx(&kb, 0); kk += 8; |
151 | nx(&kb, kk); nx(&ka, 0); kk += 8; |
152 | r--; |
153 | } |
154 | nx(&ka, kk); kk += 8; |
155 | } |
156 | |
157 | /* --- @safer_init@, @safersk_init@ --- * |
158 | * |
159 | * Arguments: @safer_ctx *k@ = pointer to context to initialize |
160 | * @const void *buf@ = pointer to key material |
161 | * @size_t sz@ = size of key material in bytes |
162 | * |
163 | * Returns: --- |
164 | * |
165 | * Use: Initializes an SAFER expanded key. A default number of |
166 | * rounds is chosen, based on the key length. |
167 | */ |
168 | |
169 | void safer_init(safer_ctx *k, const void *buf, size_t sz) |
170 | { |
171 | safer_setup(k, sz == 8 ? 6 : 10, 0, buf, sz); |
172 | } |
173 | |
174 | void safersk_init(safer_ctx *k, const void *buf, size_t sz) |
175 | { |
176 | safer_setup(k, sz == 8 ? 8 : 10, SAFER_SK, buf, sz); |
177 | } |
178 | |
179 | /* --- @safer_eblk@, @safer_dblk@ --- * |
180 | * |
181 | * Arguments: @const safer_ctx *k@ = pointer to SAFER context |
182 | * @const uint32 s[2]@ = pointer to source block |
183 | * @const uint32 d[2]@ = pointer to destination block |
184 | * |
185 | * Returns: --- |
186 | * |
187 | * Use: Low-level block encryption and decryption. |
188 | */ |
189 | |
190 | #define UNPACK(src, a, b, c, d, e, f, g, h) do { \ |
191 | a = U8(src[0] >> 24); b = U8(src[0] >> 16); \ |
192 | c = U8(src[0] >> 8); d = U8(src[0] >> 0); \ |
193 | e = U8(src[1] >> 24); f = U8(src[1] >> 16); \ |
194 | g = U8(src[1] >> 8); h = U8(src[1] >> 0); \ |
195 | } while (0) |
196 | |
197 | #define PACK(dst, a, b, c, d, e, f, g, h) do { \ |
198 | dst[0] = (U8(a) << 24) | (U8(b) << 16) | (U8(c) << 8) | U8(d); \ |
199 | dst[1] = (U8(e) << 24) | (U8(f) << 16) | (U8(g) << 8) | U8(h); \ |
200 | } while (0) |
201 | |
202 | #define F(x, y) y += x, x += y |
203 | #define G(x, y) x -= y, y -= x |
204 | |
205 | #define PHT(a, b, c, d, e, f, g, h) do { \ |
206 | F(a, b); F(c, d); F(e, f); F(g, h); \ |
207 | F(a, c); F(e, g); F(b, d); F(f, h); \ |
208 | F(a, e); F(b, f); F(c, g); F(d, h); \ |
209 | } while (0) |
210 | #define IPHT(a, b, c, d, e, f, g, h) do { \ |
211 | G(a, e); G(b, f); G(c, g); G(d, h); \ |
212 | G(a, c); G(e, g); G(b, d); G(f, h); \ |
213 | G(a, b); G(c, d); G(e, f); G(g, h); \ |
214 | } while (0) |
215 | |
216 | #define KXA(k, a, b, c, d, e, f, g, h) do { \ |
217 | a ^= *k++; b += *k++; c += *k++; d ^= *k++; \ |
218 | e ^= *k++; f += *k++; g += *k++; h ^= *k++; \ |
219 | } while (0) |
220 | #define SUB(a, b, c, d, e, f, g, h) do { \ |
221 | a = s[U8(a)]; b = si[U8(b)]; c = si[U8(c)]; d = s[U8(d)]; \ |
222 | e = s[U8(e)]; f = si[U8(f)]; g = si[U8(g)]; h = s[U8(h)]; \ |
223 | } while (0) |
224 | #define KAX(k, a, b, c, d, e, f, g, h) do { \ |
225 | a += *k++; b ^= *k++; c ^= *k++; d += *k++; \ |
226 | e += *k++; f ^= *k++; g ^= *k++; h += *k++; \ |
227 | } while (0) |
228 | |
229 | #define KXS(k, a, b, c, d, e, f, g, h) do { \ |
230 | h ^= *--k; g -= *--k; f -= *--k; e ^= *--k; \ |
231 | d ^= *--k; c -= *--k; b -= *--k; a ^= *--k; \ |
232 | } while (0) |
233 | #define ISUB(a, b, c, d, e, f, g, h) do { \ |
234 | a = si[U8(a)]; b = s[U8(b)]; c = s[U8(c)]; d = si[U8(d)]; \ |
235 | e = si[U8(e)]; f = s[U8(f)]; g = s[U8(g)]; h = si[U8(h)]; \ |
236 | } while (0) |
237 | #define KSX(k, a, b, c, d, e, f, g, h) do { \ |
238 | h -= *--k; g ^= *--k; f ^= *--k; e -= *--k; \ |
239 | d -= *--k; c ^= *--k; b ^= *--k; a -= *--k; \ |
240 | } while (0) |
241 | |
242 | #define EROUND(k, a, b, c, d, e, f, g, h) do { \ |
243 | KXA(k, a, b, c, d, e, f, g, h); \ |
244 | SUB(a, b, c, d, e, f, g, h); \ |
245 | KAX(k, a, b, c, d, e, f, g, h); \ |
246 | PHT(a, b, c, d, e, f, g, h); \ |
247 | } while (0) |
248 | |
249 | #define DROUND(k, a, b, c, d, e, f, g, h) do { \ |
250 | IPHT(a, b, c, d, e, f, g, h); \ |
251 | KSX(k, a, b, c, d, e, f, g, h); \ |
252 | ISUB(a, b, c, d, e, f, g, h); \ |
253 | KXS(k, a, b, c, d, e, f, g, h); \ |
254 | } while (0) |
255 | |
256 | |
257 | void safer_eblk(const safer_ctx *k, const uint32 *src, uint32 *dst) |
258 | { |
259 | octet a, b, c, d, e, f, g, h; |
260 | unsigned r = k->r; |
261 | const octet *kk = k->k; |
262 | |
263 | UNPACK(src, a, b, c, d, e, f, g, h); |
264 | while (r >= 3) { |
265 | EROUND(kk, a, b, c, d, e, f, g, h); |
266 | EROUND(kk, a, e, b, f, c, g, d, h); |
267 | EROUND(kk, a, c, e, g, b, d, f, h); |
268 | r -= 3; |
269 | } |
270 | switch (r) { |
271 | case 0: |
272 | KXA(kk, a, b, c, d, e, f, g, h); |
273 | PACK(dst, a, b, c, d, e, f, g ,h); |
274 | break; |
275 | case 1: |
276 | EROUND(kk, a, b, c, d, e, f, g, h); |
277 | KXA(kk, a, e, b, f, c, g, d, h); |
278 | PACK(dst, a, e, b, f, c, g, d, h); |
279 | break; |
280 | case 2: |
281 | EROUND(kk, a, b, c, d, e, f, g, h); |
282 | EROUND(kk, a, e, b, f, c, g, d, h); |
283 | KXA(kk, a, c, e, g, b, d, f, h); |
284 | PACK(dst, a, c, e, g, b, d, f, h); |
285 | break; |
286 | } |
287 | } |
288 | |
289 | void safer_dblk(const safer_ctx *k, const uint32 *src, uint32 *dst) |
290 | { |
291 | octet a, b, c, d, e, f, g, h; |
292 | unsigned r = k->r; |
293 | const octet *kk = k->k + 16 * r + 8; |
294 | switch (r%3) { |
295 | default: |
296 | case 0: |
297 | UNPACK(src, a, b, c, d, e, f, g, h); |
298 | KXS(kk, a, b, c, d, e, f, g, h); |
299 | break; |
300 | case 1: |
301 | UNPACK(src, a, e, b, f, c, g, d, h); |
302 | KXS(kk, a, e, b, f, c, g, d, h); |
303 | r--; |
304 | goto one_round; |
305 | case 2: |
306 | UNPACK(src, a, c, e, g, b, d, f, h); |
307 | KXS(kk, a, c, e, g, b, d, f, h); |
308 | r -= 2; |
309 | DROUND(kk, a, e, b, f, c, g, d, h); |
310 | one_round: |
311 | DROUND(kk, a, b, c, d, e, f, g, h); |
312 | break; |
313 | } |
314 | while (r) { |
315 | DROUND(kk, a, c, e, g, b, d, f, h); |
316 | DROUND(kk, a, e, b, f, c, g, d, h); |
317 | DROUND(kk, a, b, c, d, e, f, g, h); |
318 | r -= 3; |
319 | } |
320 | PACK(dst, a, b, c, d, e, f, g, h); |
321 | } |
322 | |
323 | BLKC_TEST(SAFER, safer) |
324 | |
325 | /*----- That's all, folks -------------------------------------------------*/ |