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[u/mdw/catacomb] / symm / blowfish.c
1 /* -*-c-*-
2 *
3 * The Blowfish block cipher
4 *
5 * (c) 1998 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 <mLib/bits.h>
31
32 #include "blowfish.h"
33 #include "blowfish-tab.h"
34 #include "blkc.h"
35 #include "gcipher.h"
36 #include "paranoia.h"
37
38 /*----- Global variables --------------------------------------------------*/
39
40 static const blowfish_ctx ikey = BLOWFISH_IKEY;
41
42 const octet blowfish_keysz[] = { KSZ_RANGE, BLOWFISH_KEYSZ, 1, 56, 1 };
43
44 /*----- Macros ------------------------------------------------------------*/
45
46 #define ROUND(k, x, y, r) do { \
47 x ^= *r; \
48 y ^= ((k->s0[U8(x >> 24)] + \
49 k->s1[U8(x >> 16)]) ^ \
50 k->s2[U8(x >> 8)]) + \
51 k->s3[U8(x >> 0)]; \
52 } while (0)
53
54 #define EBLK(k, a, b, c, d) do { \
55 const uint32 *_r = k->p; \
56 uint32 _x = a; \
57 uint32 _y = b; \
58 ROUND(k, _x, _y, _r++); \
59 ROUND(k, _y, _x, _r++); \
60 ROUND(k, _x, _y, _r++); \
61 ROUND(k, _y, _x, _r++); \
62 ROUND(k, _x, _y, _r++); \
63 ROUND(k, _y, _x, _r++); \
64 ROUND(k, _x, _y, _r++); \
65 ROUND(k, _y, _x, _r++); \
66 ROUND(k, _x, _y, _r++); \
67 ROUND(k, _y, _x, _r++); \
68 ROUND(k, _x, _y, _r++); \
69 ROUND(k, _y, _x, _r++); \
70 ROUND(k, _x, _y, _r++); \
71 ROUND(k, _y, _x, _r++); \
72 ROUND(k, _x, _y, _r++); \
73 ROUND(k, _y, _x, _r++); \
74 c = _y ^ k->p[17]; \
75 d = _x ^ k->p[16]; \
76 } while (0)
77
78 #define DBLK(k, a, b, c, d) do { \
79 const uint32 *_r = k->p + 18; \
80 uint32 _x = a; \
81 uint32 _y = b; \
82 ROUND(k, _x, _y, --_r); \
83 ROUND(k, _y, _x, --_r); \
84 ROUND(k, _x, _y, --_r); \
85 ROUND(k, _y, _x, --_r); \
86 ROUND(k, _x, _y, --_r); \
87 ROUND(k, _y, _x, --_r); \
88 ROUND(k, _x, _y, --_r); \
89 ROUND(k, _y, _x, --_r); \
90 ROUND(k, _x, _y, --_r); \
91 ROUND(k, _y, _x, --_r); \
92 ROUND(k, _x, _y, --_r); \
93 ROUND(k, _y, _x, --_r); \
94 ROUND(k, _x, _y, --_r); \
95 ROUND(k, _y, _x, --_r); \
96 ROUND(k, _x, _y, --_r); \
97 ROUND(k, _y, _x, --_r); \
98 c = _y ^ k->p[0]; \
99 d = _x ^ k->p[1]; \
100 } while (0)
101
102 /*----- Low-level encryption interface ------------------------------------*/
103
104 /* --- @blowfish_init@ --- *
105 *
106 * Arguments: @blowfish_ctx *k@ = pointer to key block to fill in
107 * @const void *buf@ = pointer to buffer of key material
108 * @size_t sz@ = size of key material
109 *
110 * Returns: ---
111 *
112 * Use: Initializes a Blowfish key buffer. Blowfish accepts
113 * a more-or-less arbitrary size key.
114 */
115
116 void blowfish_init(blowfish_ctx *k, const void *buf, size_t sz)
117 {
118 KSZ_ASSERT(blowfish, sz);
119
120 /* --- Copy the initial value over --- */
121
122 memcpy(k, &ikey, sizeof(ikey));
123
124 /* --- Initialize the %$P$% array --- */
125
126 {
127 const octet *p = buf;
128 const octet *q = p + sz;
129 int i = 0, j = 0;
130 uint32 x = 0;
131
132 while (i < 18) {
133 x = (x << 8) | U8(*p++);
134 if (p >= q)
135 p = buf;
136 if (++j >= 4) {
137 k->p[i++] ^= x;
138 x = 0;
139 j = 0;
140 }
141 }
142
143 x = 0;
144 }
145
146 /* --- Now mangle the complete array of keys --- */
147
148 {
149 uint32 b[2];
150 int i;
151
152 b[0] = b[1] = 0;
153
154 for (i = 0; i < 18; i += 2) {
155 blowfish_eblk(k, b, b);
156 k->p[i] = b[0]; k->p[i + 1] = b[1];
157 }
158
159 for (i = 0; i < 256; i += 2) {
160 blowfish_eblk(k, b, b);
161 k->s0[i] = b[0]; k->s0[i + 1] = b[1];
162 }
163
164 for (i = 0; i < 256; i += 2) {
165 blowfish_eblk(k, b, b);
166 k->s1[i] = b[0]; k->s1[i + 1] = b[1];
167 }
168
169 for (i = 0; i < 256; i += 2) {
170 blowfish_eblk(k, b, b);
171 k->s2[i] = b[0]; k->s2[i + 1] = b[1];
172 }
173
174 for (i = 0; i < 256; i += 2) {
175 blowfish_eblk(k, b, b);
176 k->s3[i] = b[0]; k->s3[i + 1] = b[1];
177 }
178
179 BURN(b);
180 }
181 }
182
183 /* --- @blowfish_eblk@, @blowfish_dblk@ --- *
184 *
185 * Arguments: @const blowfish_ctx *k@ = pointer to key block
186 * @const uint32 s[2]@ = pointer to source block
187 * @uint32 d[2]@ = pointer to destination block
188 *
189 * Returns: ---
190 *
191 * Use: Low-level block encryption and decryption.
192 */
193
194 void blowfish_eblk(const blowfish_ctx *k, const uint32 *s, uint32 *d)
195 {
196 EBLK(k, s[0], s[1], d[0], d[1]);
197 }
198
199 void blowfish_dblk(const blowfish_ctx *k, const uint32 *s, uint32 *d)
200 {
201 DBLK(k, s[0], s[1], d[0], d[1]);
202 }
203
204 BLKC_TEST(BLOWFISH, blowfish)
205
206 /*----- That's all, folks -------------------------------------------------*/
Catacomb cryptographic library (downstream of http://git.distorted.org.uk/~mdw/catacomb/)