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1 | /* -*-c-*- |
2 | * |
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3 | * The SAFER block cipher |
4 | * |
5 | * (c) 2001 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 <stdio.h> |
32 | |
33 | #include <mLib/bits.h> |
34 | |
35 | #include "blkc.h" |
36 | #include "gcipher.h" |
37 | #include "paranoia.h" |
38 | #include "safer.h" |
39 | #include "safer-tab.h" |
40 | |
41 | /*----- Global variables --------------------------------------------------*/ |
42 | |
43 | const octet safer_keysz[] = { KSZ_SET, 8, 16, 0 }; |
44 | |
45 | /*----- Important tables --------------------------------------------------*/ |
46 | |
47 | static const octet s[265] = SAFER_S, si[256] = SAFER_SI; |
48 | |
49 | /*----- Main code ---------------------------------------------------------*/ |
50 | |
51 | /* --- @safer_setup@ --- * |
52 | * |
53 | * Arguments: @safer_ctx *k@ = pointer to context to initialize |
54 | * @unsigned r@ = number of rounds wanted |
55 | * @unsigned f@ = various other flags |
56 | * @const void *buf@ = pointer to key material |
57 | * @size_t sz@ = size of key material in bytes |
58 | * |
59 | * Returns: --- |
60 | * |
61 | * Use: Initializes an SAFER expanded key. A default number of |
62 | * rounds is chosen, based on the key length. |
63 | */ |
64 | |
65 | struct ksched { |
66 | unsigned i; |
67 | octet x[9]; |
68 | }; |
69 | |
70 | static void init(struct ksched *t, const octet *k) |
71 | { |
72 | memcpy(t->x, k, 8); |
73 | t->i = 1; |
74 | } |
75 | |
76 | static void init_sk(struct ksched *t, const octet *k) |
77 | { |
78 | unsigned i; |
79 | octet x; |
80 | memcpy(t->x, k, 8); |
81 | for (x = 0, i = 0; i < 8; x ^= k[i++]) |
82 | ; |
83 | t->x[8] = x; |
84 | t->i = 1; |
85 | } |
86 | |
87 | static void next(struct ksched *t, octet *k) |
88 | { |
89 | unsigned i; |
90 | if (k) { |
91 | memcpy(k, t->x, 8); |
92 | if (t->i > 1) { |
93 | for (i = 0; i < 8; i++) |
94 | k[i] += s[s[U8(9*t->i + i + 1)]]; |
95 | } |
96 | } |
97 | for (i = 0; i < 8; i++) |
98 | t->x[i] = ROL8(t->x[i], 3); |
99 | t->i++; |
100 | } |
101 | |
102 | static void next_sk(struct ksched *t, octet *k) |
103 | { |
104 | unsigned i; |
105 | i = (t->i - 1)%9; |
106 | if (k) { |
107 | if (i < 2) |
108 | memcpy(k, t->x + i, 8); |
109 | else { |
110 | memcpy(k, t->x + i, 9 - i); |
111 | memcpy(k + 9 - i, t->x, i - 1); |
112 | } |
113 | if (t->i > 1) { |
114 | for (i = 0; i < 8; i++) |
115 | k[i] += s[s[U8(9*t->i + i + 1)]]; |
116 | } |
117 | } |
118 | for (i = 0; i < 9; i++) |
119 | t->x[i] = ROL8(t->x[i], 3); |
120 | t->i++; |
121 | } |
122 | |
123 | void safer_setup(safer_ctx *k, unsigned r, unsigned f, |
124 | const void *buf, size_t sz) |
125 | { |
126 | struct ksched ka, kb; |
127 | void (*in)(struct ksched *, const octet *); |
128 | void (*nx)(struct ksched *, octet *); |
129 | octet *kk; |
130 | |
131 | assert(r <= SAFER_MAXROUNDS); |
132 | KSZ_ASSERT(safer, sz); |
133 | |
134 | if (f & SAFER_SK) { |
135 | in = init_sk; |
136 | nx = next_sk; |
137 | } else { |
138 | in = init; |
139 | nx = next; |
140 | } |
141 | |
142 | in(&kb, buf); |
143 | in(&ka, sz == 8 ? buf : (const octet *)buf + 8); |
144 | |
145 | k->r = r; |
146 | kk = k->k; |
147 | while (r) { |
148 | nx(&ka, kk); nx(&kb, 0); kk += 8; |
149 | nx(&kb, kk); nx(&ka, 0); kk += 8; |
150 | r--; |
151 | } |
152 | nx(&ka, kk); kk += 8; |
153 | } |
154 | |
155 | /* --- @safer_init@, @safersk_init@ --- * |
156 | * |
157 | * Arguments: @safer_ctx *k@ = pointer to context to initialize |
158 | * @const void *buf@ = pointer to key material |
159 | * @size_t sz@ = size of key material in bytes |
160 | * |
161 | * Returns: --- |
162 | * |
163 | * Use: Initializes an SAFER expanded key. A default number of |
164 | * rounds is chosen, based on the key length. |
165 | */ |
166 | |
167 | void safer_init(safer_ctx *k, const void *buf, size_t sz) |
168 | { |
169 | safer_setup(k, sz == 8 ? 6 : 10, 0, buf, sz); |
170 | } |
171 | |
172 | void safersk_init(safer_ctx *k, const void *buf, size_t sz) |
173 | { |
174 | safer_setup(k, sz == 8 ? 8 : 10, SAFER_SK, buf, sz); |
175 | } |
176 | |
177 | /* --- @safer_eblk@, @safer_dblk@ --- * |
178 | * |
179 | * Arguments: @const safer_ctx *k@ = pointer to SAFER context |
180 | * @const uint32 s[2]@ = pointer to source block |
181 | * @const uint32 d[2]@ = pointer to destination block |
182 | * |
183 | * Returns: --- |
184 | * |
185 | * Use: Low-level block encryption and decryption. |
186 | */ |
187 | |
188 | #define UNPACK(src, a, b, c, d, e, f, g, h) do { \ |
189 | a = U8(src[0] >> 24); b = U8(src[0] >> 16); \ |
190 | c = U8(src[0] >> 8); d = U8(src[0] >> 0); \ |
191 | e = U8(src[1] >> 24); f = U8(src[1] >> 16); \ |
192 | g = U8(src[1] >> 8); h = U8(src[1] >> 0); \ |
193 | } while (0) |
194 | |
195 | #define PACK(dst, a, b, c, d, e, f, g, h) do { \ |
196 | dst[0] = (U8(a) << 24) | (U8(b) << 16) | (U8(c) << 8) | U8(d); \ |
197 | dst[1] = (U8(e) << 24) | (U8(f) << 16) | (U8(g) << 8) | U8(h); \ |
198 | } while (0) |
199 | |
200 | #define F(x, y) y += x, x += y |
201 | #define G(x, y) x -= y, y -= x |
202 | |
203 | #define PHT(a, b, c, d, e, f, g, h) do { \ |
204 | F(a, b); F(c, d); F(e, f); F(g, h); \ |
205 | F(a, c); F(e, g); F(b, d); F(f, h); \ |
206 | F(a, e); F(b, f); F(c, g); F(d, h); \ |
207 | } while (0) |
208 | #define IPHT(a, b, c, d, e, f, g, h) do { \ |
209 | G(a, e); G(b, f); G(c, g); G(d, h); \ |
210 | G(a, c); G(e, g); G(b, d); G(f, h); \ |
211 | G(a, b); G(c, d); G(e, f); G(g, h); \ |
212 | } while (0) |
213 | |
214 | #define KXA(k, a, b, c, d, e, f, g, h) do { \ |
215 | a ^= *k++; b += *k++; c += *k++; d ^= *k++; \ |
216 | e ^= *k++; f += *k++; g += *k++; h ^= *k++; \ |
217 | } while (0) |
218 | #define SUB(a, b, c, d, e, f, g, h) do { \ |
219 | a = s[U8(a)]; b = si[U8(b)]; c = si[U8(c)]; d = s[U8(d)]; \ |
220 | e = s[U8(e)]; f = si[U8(f)]; g = si[U8(g)]; h = s[U8(h)]; \ |
221 | } while (0) |
222 | #define KAX(k, a, b, c, d, e, f, g, h) do { \ |
223 | a += *k++; b ^= *k++; c ^= *k++; d += *k++; \ |
224 | e += *k++; f ^= *k++; g ^= *k++; h += *k++; \ |
225 | } while (0) |
226 | |
227 | #define KXS(k, a, b, c, d, e, f, g, h) do { \ |
228 | h ^= *--k; g -= *--k; f -= *--k; e ^= *--k; \ |
229 | d ^= *--k; c -= *--k; b -= *--k; a ^= *--k; \ |
230 | } while (0) |
231 | #define ISUB(a, b, c, d, e, f, g, h) do { \ |
232 | a = si[U8(a)]; b = s[U8(b)]; c = s[U8(c)]; d = si[U8(d)]; \ |
233 | e = si[U8(e)]; f = s[U8(f)]; g = s[U8(g)]; h = si[U8(h)]; \ |
234 | } while (0) |
235 | #define KSX(k, a, b, c, d, e, f, g, h) do { \ |
236 | h -= *--k; g ^= *--k; f ^= *--k; e -= *--k; \ |
237 | d -= *--k; c ^= *--k; b ^= *--k; a -= *--k; \ |
238 | } while (0) |
239 | |
240 | #define EROUND(k, a, b, c, d, e, f, g, h) do { \ |
241 | KXA(k, a, b, c, d, e, f, g, h); \ |
242 | SUB(a, b, c, d, e, f, g, h); \ |
243 | KAX(k, a, b, c, d, e, f, g, h); \ |
244 | PHT(a, b, c, d, e, f, g, h); \ |
245 | } while (0) |
246 | |
247 | #define DROUND(k, a, b, c, d, e, f, g, h) do { \ |
248 | IPHT(a, b, c, d, e, f, g, h); \ |
249 | KSX(k, a, b, c, d, e, f, g, h); \ |
250 | ISUB(a, b, c, d, e, f, g, h); \ |
251 | KXS(k, a, b, c, d, e, f, g, h); \ |
252 | } while (0) |
253 | |
254 | |
255 | void safer_eblk(const safer_ctx *k, const uint32 *src, uint32 *dst) |
256 | { |
257 | octet a, b, c, d, e, f, g, h; |
258 | unsigned r = k->r; |
259 | const octet *kk = k->k; |
260 | |
261 | UNPACK(src, a, b, c, d, e, f, g, h); |
262 | while (r >= 3) { |
263 | EROUND(kk, a, b, c, d, e, f, g, h); |
264 | EROUND(kk, a, e, b, f, c, g, d, h); |
265 | EROUND(kk, a, c, e, g, b, d, f, h); |
266 | r -= 3; |
267 | } |
268 | switch (r) { |
269 | case 0: |
270 | KXA(kk, a, b, c, d, e, f, g, h); |
271 | PACK(dst, a, b, c, d, e, f, g ,h); |
272 | break; |
273 | case 1: |
274 | EROUND(kk, a, b, c, d, e, f, g, h); |
275 | KXA(kk, a, e, b, f, c, g, d, h); |
276 | PACK(dst, a, e, b, f, c, g, d, h); |
277 | break; |
278 | case 2: |
279 | EROUND(kk, a, b, c, d, e, f, g, h); |
280 | EROUND(kk, a, e, b, f, c, g, d, h); |
281 | KXA(kk, a, c, e, g, b, d, f, h); |
282 | PACK(dst, a, c, e, g, b, d, f, h); |
283 | break; |
284 | } |
285 | } |
286 | |
287 | void safer_dblk(const safer_ctx *k, const uint32 *src, uint32 *dst) |
288 | { |
289 | octet a, b, c, d, e, f, g, h; |
290 | unsigned r = k->r; |
291 | const octet *kk = k->k + 16 * r + 8; |
292 | switch (r%3) { |
293 | default: |
294 | case 0: |
295 | UNPACK(src, a, b, c, d, e, f, g, h); |
296 | KXS(kk, a, b, c, d, e, f, g, h); |
297 | break; |
298 | case 1: |
299 | UNPACK(src, a, e, b, f, c, g, d, h); |
300 | KXS(kk, a, e, b, f, c, g, d, h); |
301 | r--; |
302 | goto one_round; |
303 | case 2: |
304 | UNPACK(src, a, c, e, g, b, d, f, h); |
305 | KXS(kk, a, c, e, g, b, d, f, h); |
306 | r -= 2; |
307 | DROUND(kk, a, e, b, f, c, g, d, h); |
308 | one_round: |
309 | DROUND(kk, a, b, c, d, e, f, g, h); |
310 | break; |
311 | } |
312 | while (r) { |
313 | DROUND(kk, a, c, e, g, b, d, f, h); |
314 | DROUND(kk, a, e, b, f, c, g, d, h); |
315 | DROUND(kk, a, b, c, d, e, f, g, h); |
316 | r -= 3; |
317 | } |
318 | PACK(dst, a, b, c, d, e, f, g, h); |
319 | } |
320 | |
321 | BLKC_TEST(SAFER, safer) |
322 | |
323 | /*----- That's all, folks -------------------------------------------------*/ |