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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: mars.c,v 1.2 2004/04/08 01:36:15 mdw Exp $ |
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4 | * |
5 | * The MARS 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 "mars.h" |
40 | #include "mars-tab.h" |
41 | #include "paranoia.h" |
42 | |
43 | /*----- Global variables --------------------------------------------------*/ |
44 | |
45 | const octet mars_keysz[] = { KSZ_RANGE, MARS_KEYSZ, 0, 56, 4 }; |
46 | |
47 | /*----- Useful tables -----------------------------------------------------*/ |
48 | |
49 | static const uint32 s[512] = MARS_S; |
50 | #define s0 (s + 0) |
51 | #define s1 (s + 256) |
52 | #define bb (s + 265) |
53 | |
54 | /*----- Main code ---------------------------------------------------------*/ |
55 | |
56 | /* --- @mars_init@ --- * |
57 | * |
58 | * Arguments: @mars_ctx *k@ = pointer to key block to fill in |
59 | * @const void *buf@ = pointer to buffer of key material |
60 | * @size_t sz@ = size of key material |
61 | * |
62 | * Returns: --- |
63 | * |
64 | * Use: Initializes a MARS key buffer. MARS accepts key sizes |
65 | * between 128 and 448 bits which are a multiple of 32 bits. |
66 | */ |
67 | |
68 | void mars_init(mars_ctx *k, const void *buf, size_t sz) |
69 | { |
70 | uint32 t[15]; |
71 | uint32 *kk = k->k; |
72 | const octet *p; |
73 | unsigned i, j, ii; |
74 | |
75 | KSZ_ASSERT(mars, sz); |
76 | |
77 | /* --- Copy the key into the temporary buffer --- */ |
78 | |
79 | p = buf; |
80 | for (i = 0; i < sz/4; i++) { |
81 | t[i] = LOAD32_L(p); |
82 | p += 4; |
83 | } |
84 | t[i++] = sz/4; |
85 | for (; i < 15; i++) |
86 | t[i] = 0; |
87 | |
88 | /* --- Now spit out the actual key material --- */ |
89 | |
90 | for (j = 0; j < 4; j++) { |
91 | uint32 x; |
92 | |
93 | /* --- Do the linear mixing stage --- */ |
94 | |
95 | for (i = 0; i < 15; i++) { |
96 | x = t[(i + 8)%15] ^ t[(i + 13)%15]; |
97 | t[i] ^= ROL32(x, 3) ^ ((i << 2) | j); |
98 | } |
99 | |
100 | /* --- Now do the Feistel stirring stage --- */ |
101 | |
102 | x = t[14]; |
103 | for (ii = 0; ii < 4; ii++) { |
104 | for (i = 0; i < 15; i++) { |
105 | x = t[i] + s[x & 511u]; |
106 | t[i] = x = ROL32(x, 9); |
107 | } |
108 | } |
109 | |
110 | /* --- And spit out the key material --- */ |
111 | |
112 | for (i = 0; i < 10; i++) |
113 | *kk++ = t[(4 * i)%15]; |
114 | } |
115 | |
116 | /* --- Finally, fix up the multiplicative entries --- */ |
117 | |
118 | for (i = 5; i < 37; i += 2) { |
119 | uint32 w, m, x; |
120 | j = k->k[i] & 3u; |
121 | w = k->k[i] | 3u; |
122 | |
123 | /* --- Compute the magic mask value --- */ |
124 | |
125 | m = 0; |
126 | for (ii = 0; ii <= 22; ii++) { |
127 | x = w >> ii; |
128 | if ((x & 0x3ff) == 0x3ff || (x & 0x3ff) == 0) |
129 | m |= 0x3ff << ii; |
130 | } |
131 | m &= ~(((w ^ (w << 1)) | (w ^ (w >> 1))) | 0x80000003); |
132 | |
133 | /* --- Add in the bias entry to fix up the key --- */ |
134 | |
135 | x = ROL32(bb[j], k->k[i - 1]); |
136 | k->k[i] = w ^ (x & m); |
137 | } |
138 | } |
139 | |
140 | /* --- @mars_eblk@, @mars_dblk@ --- * |
141 | * |
142 | * Arguments: @const mars_ctx *k@ = pointer to key block |
143 | * @const uint32 s[4]@ = pointer to source block |
144 | * @uint32 d[4]@ = pointer to destination block |
145 | * |
146 | * Returns: --- |
147 | * |
148 | * Use: Low-level block encryption and decryption. |
149 | */ |
150 | |
151 | #define KADD(k, a, b, c, d) a += *k++, b += *k++, c += *k++, d += *k++ |
152 | #define KSUB(k, a, b, c, d) a -= *k++, b -= *k++, c -= *k++, d -= *k++ |
153 | #define IKADD(k, a, b, c, d) d += *--k, c += *--k, b += *--k, a += *--k |
154 | #define IKSUB(k, a, b, c, d) d -= *--k, c -= *--k, b -= *--k, a -= *--k |
155 | |
156 | #define MIX(a, b, c, d) do { \ |
157 | b ^= s0[(a >> 0) & 0xff]; \ |
158 | b += s1[(a >> 8) & 0xff]; \ |
159 | c += s0[(a >> 16) & 0xff]; \ |
160 | d ^= s1[(a >> 24) & 0xff]; \ |
161 | a = ROL32(a, 8); \ |
162 | } while (0) |
163 | |
164 | #define IMIX(a, b, c, d) do { \ |
165 | a = ROR32(a, 8); \ |
166 | d ^= s1[(a >> 24) & 0xff]; \ |
167 | c -= s0[(a >> 16) & 0xff]; \ |
168 | b -= s1[(a >> 8) & 0xff]; \ |
169 | b ^= s0[(a >> 0) & 0xff]; \ |
170 | } while (0) |
171 | |
172 | #define E(x, y, z, k, a) do { \ |
173 | uint32 kx = *k++, ky = *k++; \ |
174 | y = a + kx; \ |
175 | a = ROL32(a, 13); z = a * ky; z = ROL32(z, 5); \ |
176 | x = s[y & 511u] ^ z; y = ROL32(y, z); \ |
177 | z = ROL32(z, 5); x ^= z; x = ROL32(x, z); \ |
178 | } while (0) |
179 | |
180 | #define IE(x, y, z, k, a) do { \ |
181 | uint32 ky = *--k, kx = *--k; \ |
182 | z = a * ky; \ |
183 | a = ROR32(a, 13); y = a + kx; z = ROL32(z, 5); \ |
184 | x = s[y & 511u] ^ z; y = ROL32(y, z); \ |
185 | z = ROL32(z, 5); x ^= z; x = ROL32(x, z); \ |
186 | } while (0) |
187 | |
188 | #define ROUND(k, a, b, c, d) do { \ |
189 | uint32 x, y, z; \ |
190 | E(x, y, z, k, a); \ |
191 | b += x; c += y; d ^= z; \ |
192 | } while (0) |
193 | |
194 | #define IROUND(k, a, b, c, d) do { \ |
195 | uint32 x, y, z; \ |
196 | IE(x, y, z, k, a); \ |
197 | b -= x; c -= y; d ^= z; \ |
198 | } while (0) |
199 | |
200 | void mars_eblk(const mars_ctx *k, const uint32 *src, uint32 *dst) |
201 | { |
202 | uint32 a, b, c, d; |
203 | const uint32 *kk = k->k; |
204 | |
205 | a = src[0], b = src[1], c = src[2], d = src[3]; |
206 | KADD(kk, a, b, c, d); |
207 | |
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 | MIX(a, b, c, d); a += d; MIX(b, c, d, a); b += c; |
211 | MIX(c, d, a, b); MIX(d, a, b, c); |
212 | |
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 | ROUND(kk, a, b, c, d); ROUND(kk, b, c, d, a); |
216 | ROUND(kk, c, d, a, b); ROUND(kk, d, a, b, c); |
217 | |
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 | ROUND(kk, a, d, c, b); ROUND(kk, b, a, d, c); |
221 | ROUND(kk, c, b, a, d); ROUND(kk, d, c, b, a); |
222 | |
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 | IMIX(a, d, c, b); IMIX(b, a, d, c); |
226 | c -= b; IMIX(c, b, a, d); d -= a; IMIX(d, c, b, a); |
227 | |
228 | KSUB(kk, a, b, c, d); |
229 | dst[0] = a; dst[1] = b; dst[2] = c; dst[3] = d; |
230 | } |
231 | |
232 | void mars_dblk(const mars_ctx *k, const uint32 *src, uint32 *dst) |
233 | { |
234 | uint32 a, b, c, d; |
235 | const uint32 *kk = k->k + 40; |
236 | |
237 | a = src[0], b = src[1], c = src[2], d = src[3]; |
238 | IKADD(kk, a, b, c, d); |
239 | |
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 | MIX(d, c, b, a); d += a; MIX(c, b, a, d); c += b; |
243 | MIX(b, a, d, c); MIX(a, d, c, b); |
244 | |
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 | IROUND(kk, d, c, b, a); IROUND(kk, c, b, a, d); |
248 | IROUND(kk, b, a, d, c); IROUND(kk, a, d, c, b); |
249 | |
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 | IROUND(kk, d, a, b, c); IROUND(kk, c, d, a, b); |
253 | IROUND(kk, b, c, d, a); IROUND(kk, a, b, c, d); |
254 | |
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 | IMIX(d, a, b, c); IMIX(c, d, a, b); |
258 | b -= c; IMIX(b, c, d, a); a -= d; IMIX(a, b, c, d); |
259 | |
260 | IKSUB(kk, a, b, c, d); |
261 | dst[0] = a; dst[1] = b; dst[2] = c; dst[3] = d; |
262 | } |
263 | |
264 | BLKC_TEST(MARS, mars) |
265 | |
266 | /*----- That's all, folks -------------------------------------------------*/ |