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1 | /* -*-c-*- |
2 | * |
b817bfc6 |
3 | * $Id: cast256.c,v 1.2 2004/04/08 01:36:15 mdw Exp $ |
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4 | * |
5 | * The CAST-256 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 | |
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30 | /*----- Header files ------------------------------------------------------*/ |
31 | |
32 | #include <assert.h> |
33 | #include <stdio.h> |
34 | #include <stdlib.h> |
35 | #include <string.h> |
36 | |
37 | #include <mLib/bits.h> |
38 | |
39 | #include "blkc.h" |
40 | #include "cast-base.h" |
41 | #include "cast256.h" |
42 | #include "gcipher.h" |
43 | #include "paranoia.h" |
44 | |
45 | /*----- Global variables --------------------------------------------------*/ |
46 | |
47 | const octet cast256_keysz[] = { KSZ_RANGE, CAST256_KEYSZ, 0, 32, 1 }; |
48 | |
49 | /*----- Main code ---------------------------------------------------------*/ |
50 | |
51 | /* --- @cast256_init@ --- * |
52 | * |
53 | * Arguments: @cast128_ctx *k@ = pointer to key block to fill in |
54 | * @const void *buf@ = pointer to buffer of key material |
55 | * @size_t sz@ = size of key material |
56 | * |
57 | * Returns: --- |
58 | * |
59 | * Use: Initializes a CAST-256 key buffer. CAST-256 accepts |
60 | * 256-bit keys or shorter. |
61 | */ |
62 | |
63 | void cast256_init(cast256_ctx *k, const void *buf, size_t sz) |
64 | { |
65 | const octet *p = buf; |
66 | uint32 kk[8]; |
67 | uint32 *km; |
68 | octet *kr; |
69 | unsigned i, j; |
70 | uint32 a, b, c, d, e, f, g, h; |
71 | uint32 m; |
72 | unsigned r; |
73 | |
74 | /* --- Fiddle with the key size --- */ |
75 | |
76 | KSZ_ASSERT(cast256, sz); |
77 | |
78 | /* --- Read the key into the array --- */ |
79 | |
80 | i = 0; |
81 | b = 32; a = 0; |
82 | for (;;) { |
83 | if (!sz) |
84 | break; |
85 | b -= 8; |
86 | a |= ((uint32)*p++ << b); |
87 | sz--; |
88 | if (b == 0) { |
89 | kk[i++] = a; |
90 | if (i == 8) |
91 | break; |
92 | a = 0; |
93 | b = 32; |
94 | } |
95 | } |
96 | |
97 | for (; i < 8; i++) { |
98 | kk[i] = a; |
99 | a = 0; |
100 | } |
101 | |
102 | /* --- Read the key words out --- */ |
103 | |
104 | a = kk[0]; b = kk[1]; c = kk[2]; d = kk[3]; |
105 | e = kk[4]; f = kk[5]; g = kk[6]; h = kk[7]; |
106 | |
107 | #define ROOT2 0x5a827999 |
108 | #define ROOT3 0x6ed9eba1 |
109 | |
110 | m = ROOT2; |
111 | r = 19; |
112 | |
113 | km = k->km; |
114 | kr = k->kr; |
115 | for (i = 0; i < 12; i++) { |
116 | for (j = 0; j < 2; j++) { |
117 | CAST_R1(m, r, g, h); m += ROOT3; r = (r + 17) & 0x1f; |
118 | CAST_R2(m, r, f, g); m += ROOT3; r = (r + 17) & 0x1f; |
119 | CAST_R3(m, r, e, f); m += ROOT3; r = (r + 17) & 0x1f; |
120 | CAST_R1(m, r, d, e); m += ROOT3; r = (r + 17) & 0x1f; |
121 | CAST_R2(m, r, c, d); m += ROOT3; r = (r + 17) & 0x1f; |
122 | CAST_R3(m, r, b, c); m += ROOT3; r = (r + 17) & 0x1f; |
123 | CAST_R1(m, r, a, b); m += ROOT3; r = (r + 17) & 0x1f; |
124 | CAST_R2(m, r, h, a); m += ROOT3; r = (r + 17) & 0x1f; |
125 | } |
126 | km[0] = h; km[1] = f; km[2] = d; km[3] = b; |
127 | kr[0] = a & 0x1f; kr[1] = c & 0x1f; kr[2] = e & 0x1f; kr[3] = g & 0x1f; |
128 | km += 4; kr += 4; |
129 | } |
130 | } |
131 | |
132 | /* --- @cast256_eblk@, @cast256_dblk@ --- * |
133 | * |
134 | * Arguments: @const cast256_ctx *k@ = pointer to key block |
135 | * @const uint32 s[2]@ = pointer to source block |
136 | * @uint32 d[2]@ = pointer to destination block |
137 | * |
138 | * Returns: --- |
139 | * |
140 | * Use: Low-level block encryption and decryption. |
141 | */ |
142 | |
143 | #define Q0(k, r, a, b, c, d) do { \ |
144 | CAST_R1(k[0], r[0], c, d); \ |
145 | CAST_R2(k[1], r[1], b, c); \ |
146 | CAST_R3(k[2], r[2], a, b); \ |
147 | CAST_R1(k[3], r[3], d, a); \ |
148 | } while (0) |
149 | |
150 | #define Q1(k, r, a, b, c, d) do { \ |
151 | CAST_R1(k[3], r[3], d, a); \ |
152 | CAST_R3(k[2], r[2], a, b); \ |
153 | CAST_R2(k[1], r[1], b, c); \ |
154 | CAST_R1(k[0], r[0], c, d); \ |
155 | } while (0) |
156 | |
157 | void cast256_eblk(const cast256_ctx *k, const uint32 *s, uint32 *d) |
158 | { |
159 | uint32 aa = s[0], bb = s[1], cc = s[2], dd = s[3]; |
160 | const uint32 *km = k->km; |
161 | const octet *kr = k->kr; |
162 | |
163 | Q0(km, kr, aa, bb, cc, dd); km += 4; kr += 4; |
164 | Q0(km, kr, aa, bb, cc, dd); km += 4; kr += 4; |
165 | Q0(km, kr, aa, bb, cc, dd); km += 4; kr += 4; |
166 | Q0(km, kr, aa, bb, cc, dd); km += 4; kr += 4; |
167 | Q0(km, kr, aa, bb, cc, dd); km += 4; kr += 4; |
168 | Q0(km, kr, aa, bb, cc, dd); km += 4; kr += 4; |
169 | |
170 | Q1(km, kr, aa, bb, cc, dd); km += 4; kr += 4; |
171 | Q1(km, kr, aa, bb, cc, dd); km += 4; kr += 4; |
172 | Q1(km, kr, aa, bb, cc, dd); km += 4; kr += 4; |
173 | Q1(km, kr, aa, bb, cc, dd); km += 4; kr += 4; |
174 | Q1(km, kr, aa, bb, cc, dd); km += 4; kr += 4; |
175 | Q1(km, kr, aa, bb, cc, dd); km += 4; kr += 4; |
176 | |
177 | d[0] = aa; d[1] = bb; d[2] = cc; d[3] = dd; |
178 | } |
179 | |
180 | void cast256_dblk(const cast256_ctx *k, const uint32 *s, uint32 *d) |
181 | { |
182 | uint32 aa = s[0], bb = s[1], cc = s[2], dd = s[3]; |
183 | const uint32 *km = k->km + 48; |
184 | const octet *kr = k->kr + 48; |
185 | |
186 | km -= 4; kr -= 4; Q0(km, kr, aa, bb, cc, dd); |
187 | km -= 4; kr -= 4; Q0(km, kr, aa, bb, cc, dd); |
188 | km -= 4; kr -= 4; Q0(km, kr, aa, bb, cc, dd); |
189 | km -= 4; kr -= 4; Q0(km, kr, aa, bb, cc, dd); |
190 | km -= 4; kr -= 4; Q0(km, kr, aa, bb, cc, dd); |
191 | km -= 4; kr -= 4; Q0(km, kr, aa, bb, cc, dd); |
192 | |
193 | km -= 4; kr -= 4; Q1(km, kr, aa, bb, cc, dd); |
194 | km -= 4; kr -= 4; Q1(km, kr, aa, bb, cc, dd); |
195 | km -= 4; kr -= 4; Q1(km, kr, aa, bb, cc, dd); |
196 | km -= 4; kr -= 4; Q1(km, kr, aa, bb, cc, dd); |
197 | km -= 4; kr -= 4; Q1(km, kr, aa, bb, cc, dd); |
198 | km -= 4; kr -= 4; Q1(km, kr, aa, bb, cc, dd); |
199 | |
200 | d[0] = aa; d[1] = bb; d[2] = cc; d[3] = dd; |
201 | } |
202 | |
203 | BLKC_TEST(CAST256, cast256) |
204 | |
205 | /*----- That's all, folks -------------------------------------------------*/ |