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[u/mdw/catacomb] / symm / mars.c
1 /* -*-c-*-
2 *
3 * The MARS block cipher
4 *
5 * (c) 2001 Straylight/Edgeware
6 */
7
8 /*----- Licensing notice --------------------------------------------------*
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.
16 *
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.
21 *
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
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 "mars.h"
38 #include "mars-tab.h"
39 #include "paranoia.h"
40
41 /*----- Global variables --------------------------------------------------*/
42
43 const octet mars_keysz[] = { KSZ_RANGE, MARS_KEYSZ, 0, 56, 4 };
44
45 /*----- Useful tables -----------------------------------------------------*/
46
47 static const uint32 s[512] = MARS_S;
48 #define s0 (s + 0)
49 #define s1 (s + 256)
50 #define bb (s + 265)
51
52 /*----- Main code ---------------------------------------------------------*/
53
54 /* --- @mars_init@ --- *
55 *
56 * Arguments: @mars_ctx *k@ = pointer to key block to fill in
57 * @const void *buf@ = pointer to buffer of key material
58 * @size_t sz@ = size of key material
59 *
60 * Returns: ---
61 *
62 * Use: Initializes a MARS key buffer. MARS accepts key sizes
63 * between 128 and 448 bits which are a multiple of 32 bits.
64 */
65
66 void mars_init(mars_ctx *k, const void *buf, size_t sz)
67 {
68 uint32 t[15];
69 uint32 *kk = k->k;
70 const octet *p;
71 unsigned i, j, ii;
72
73 KSZ_ASSERT(mars, sz);
74
75 /* --- Copy the key into the temporary buffer --- */
76
77 p = buf;
78 for (i = 0; i < sz/4; i++) {
79 t[i] = LOAD32_L(p);
80 p += 4;
81 }
82 t[i++] = sz/4;
83 for (; i < 15; i++)
84 t[i] = 0;
85
86 /* --- Now spit out the actual key material --- */
87
88 for (j = 0; j < 4; j++) {
89 uint32 x;
90
91 /* --- Do the linear mixing stage --- */
92
93 for (i = 0; i < 15; i++) {
94 x = t[(i + 8)%15] ^ t[(i + 13)%15];
95 t[i] ^= ROL32(x, 3) ^ ((i << 2) | j);
96 }
97
98 /* --- Now do the Feistel stirring stage --- */
99
100 x = t[14];
101 for (ii = 0; ii < 4; ii++) {
102 for (i = 0; i < 15; i++) {
103 x = t[i] + s[x & 511u];
104 t[i] = x = ROL32(x, 9);
105 }
106 }
107
108 /* --- And spit out the key material --- */
109
110 for (i = 0; i < 10; i++)
111 *kk++ = t[(4 * i)%15];
112 }
113
114 /* --- Finally, fix up the multiplicative entries --- */
115
116 for (i = 5; i < 37; i += 2) {
117 uint32 w, m, x;
118 j = k->k[i] & 3u;
119 w = k->k[i] | 3u;
120
121 /* --- Compute the magic mask value --- */
122
123 m = 0;
124 for (ii = 0; ii <= 22; ii++) {
125 x = w >> ii;
126 if ((x & 0x3ff) == 0x3ff || (x & 0x3ff) == 0)
127 m |= 0x3ff << ii;
128 }
129 m &= ~(((w ^ (w << 1)) | (w ^ (w >> 1))) | 0x80000003);
130
131 /* --- Add in the bias entry to fix up the key --- */
132
133 x = ROL32(bb[j], k->k[i - 1]);
134 k->k[i] = w ^ (x & m);
135 }
136 }
137
138 /* --- @mars_eblk@, @mars_dblk@ --- *
139 *
140 * Arguments: @const mars_ctx *k@ = pointer to key block
141 * @const uint32 s[4]@ = pointer to source block
142 * @uint32 d[4]@ = pointer to destination block
143 *
144 * Returns: ---
145 *
146 * Use: Low-level block encryption and decryption.
147 */
148
149 #define KADD(k, a, b, c, d) a += *k++, b += *k++, c += *k++, d += *k++
150 #define KSUB(k, a, b, c, d) a -= *k++, b -= *k++, c -= *k++, d -= *k++
151 #define IKADD(k, a, b, c, d) d += *--k, c += *--k, b += *--k, a += *--k
152 #define IKSUB(k, a, b, c, d) d -= *--k, c -= *--k, b -= *--k, a -= *--k
153
154 #define MIX(a, b, c, d) do { \
155 b ^= s0[(a >> 0) & 0xff]; \
156 b += s1[(a >> 8) & 0xff]; \
157 c += s0[(a >> 16) & 0xff]; \
158 d ^= s1[(a >> 24) & 0xff]; \
159 a = ROL32(a, 8); \
160 } while (0)
161
162 #define IMIX(a, b, c, d) do { \
163 a = ROR32(a, 8); \
164 d ^= s1[(a >> 24) & 0xff]; \
165 c -= s0[(a >> 16) & 0xff]; \
166 b -= s1[(a >> 8) & 0xff]; \
167 b ^= s0[(a >> 0) & 0xff]; \
168 } while (0)
169
170 #define E(x, y, z, k, a) do { \
171 uint32 kx = *k++, ky = *k++; \
172 y = a + kx; \
173 a = ROL32(a, 13); z = a * ky; z = ROL32(z, 5); \
174 x = s[y & 511u] ^ z; y = ROL32(y, z); \
175 z = ROL32(z, 5); x ^= z; x = ROL32(x, z); \
176 } while (0)
177
178 #define IE(x, y, z, k, a) do { \
179 uint32 ky = *--k, kx = *--k; \
180 z = a * ky; \
181 a = ROR32(a, 13); y = a + kx; z = ROL32(z, 5); \
182 x = s[y & 511u] ^ z; y = ROL32(y, z); \
183 z = ROL32(z, 5); x ^= z; x = ROL32(x, z); \
184 } while (0)
185
186 #define ROUND(k, a, b, c, d) do { \
187 uint32 x, y, z; \
188 E(x, y, z, k, a); \
189 b += x; c += y; d ^= z; \
190 } while (0)
191
192 #define IROUND(k, a, b, c, d) do { \
193 uint32 x, y, z; \
194 IE(x, y, z, k, a); \
195 b -= x; c -= y; d ^= z; \
196 } while (0)
197
198 void mars_eblk(const mars_ctx *k, const uint32 *src, uint32 *dst)
199 {
200 uint32 a, b, c, d;
201 const uint32 *kk = k->k;
202
203 a = src[0], b = src[1], c = src[2], d = src[3];
204 KADD(kk, a, b, c, d);
205
206 MIX(a, b, c, d); a += d; MIX(b, c, d, a); b += c;
207 MIX(c, d, a, b); MIX(d, a, b, c);
208 MIX(a, b, c, d); a += d; MIX(b, c, d, a); b += c;
209 MIX(c, d, a, b); MIX(d, a, b, c);
210
211 ROUND(kk, a, b, c, d); ROUND(kk, b, c, d, a);
212 ROUND(kk, c, d, a, b); ROUND(kk, d, a, b, c);
213 ROUND(kk, a, b, c, d); ROUND(kk, b, c, d, a);
214 ROUND(kk, c, d, a, b); ROUND(kk, d, a, b, c);
215
216 ROUND(kk, a, d, c, b); ROUND(kk, b, a, d, c);
217 ROUND(kk, c, b, a, d); ROUND(kk, d, c, b, a);
218 ROUND(kk, a, d, c, b); ROUND(kk, b, a, d, c);
219 ROUND(kk, c, b, a, d); ROUND(kk, d, c, b, a);
220
221 IMIX(a, d, c, b); IMIX(b, a, d, c);
222 c -= b; IMIX(c, b, a, d); d -= a; IMIX(d, c, b, a);
223 IMIX(a, d, c, b); IMIX(b, a, d, c);
224 c -= b; IMIX(c, b, a, d); d -= a; IMIX(d, c, b, a);
225
226 KSUB(kk, a, b, c, d);
227 dst[0] = a; dst[1] = b; dst[2] = c; dst[3] = d;
228 }
229
230 void mars_dblk(const mars_ctx *k, const uint32 *src, uint32 *dst)
231 {
232 uint32 a, b, c, d;
233 const uint32 *kk = k->k + 40;
234
235 a = src[0], b = src[1], c = src[2], d = src[3];
236 IKADD(kk, a, b, c, d);
237
238 MIX(d, c, b, a); d += a; MIX(c, b, a, d); c += b;
239 MIX(b, a, d, c); MIX(a, d, c, b);
240 MIX(d, c, b, a); d += a; MIX(c, b, a, d); c += b;
241 MIX(b, a, d, c); MIX(a, d, c, b);
242
243 IROUND(kk, d, c, b, a); IROUND(kk, c, b, a, d);
244 IROUND(kk, b, a, d, c); IROUND(kk, a, d, c, b);
245 IROUND(kk, d, c, b, a); IROUND(kk, c, b, a, d);
246 IROUND(kk, b, a, d, c); IROUND(kk, a, d, c, b);
247
248 IROUND(kk, d, a, b, c); IROUND(kk, c, d, a, b);
249 IROUND(kk, b, c, d, a); IROUND(kk, a, b, c, d);
250 IROUND(kk, d, a, b, c); IROUND(kk, c, d, a, b);
251 IROUND(kk, b, c, d, a); IROUND(kk, a, b, c, d);
252
253 IMIX(d, a, b, c); IMIX(c, d, a, b);
254 b -= c; IMIX(b, c, d, a); a -= d; IMIX(a, b, c, d);
255 IMIX(d, a, b, c); IMIX(c, d, a, b);
256 b -= c; IMIX(b, c, d, a); a -= d; IMIX(a, b, c, d);
257
258 IKSUB(kk, a, b, c, d);
259 dst[0] = a; dst[1] = b; dst[2] = c; dst[3] = d;
260 }
261
262 BLKC_TEST(MARS, mars)
263
264 /*----- That's all, folks -------------------------------------------------*/
Catacomb cryptographic library (downstream of http://git.distorted.org.uk/~mdw/catacomb/)