Root/crypto/cast6_generic.c

1/* Kernel cryptographic api.
2 * cast6.c - Cast6 cipher algorithm [rfc2612].
3 *
4 * CAST-256 (*cast6*) is a DES like Substitution-Permutation Network (SPN)
5 * cryptosystem built upon the CAST-128 (*cast5*) [rfc2144] encryption
6 * algorithm.
7 *
8 * Copyright (C) 2003 Kartikey Mahendra Bhatt <kartik_me@hotmail.com>.
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of GNU General Public License as published by the Free
12 * Software Foundation; either version 2 of the License, or (at your option)
13 * any later version.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
18 */
19
20
21#include <asm/byteorder.h>
22#include <linux/init.h>
23#include <linux/crypto.h>
24#include <linux/module.h>
25#include <linux/errno.h>
26#include <linux/string.h>
27#include <linux/types.h>
28#include <crypto/cast6.h>
29
30#define s1 cast_s1
31#define s2 cast_s2
32#define s3 cast_s3
33#define s4 cast_s4
34
35#define F1(D, r, m) ((I = ((m) + (D))), (I = rol32(I, (r))), \
36    (((s1[I >> 24] ^ s2[(I>>16)&0xff]) - s3[(I>>8)&0xff]) + s4[I&0xff]))
37#define F2(D, r, m) ((I = ((m) ^ (D))), (I = rol32(I, (r))), \
38    (((s1[I >> 24] - s2[(I>>16)&0xff]) + s3[(I>>8)&0xff]) ^ s4[I&0xff]))
39#define F3(D, r, m) ((I = ((m) - (D))), (I = rol32(I, (r))), \
40    (((s1[I >> 24] + s2[(I>>16)&0xff]) ^ s3[(I>>8)&0xff]) - s4[I&0xff]))
41
42static const u32 Tm[24][8] = {
43    { 0x5a827999, 0xc95c653a, 0x383650db, 0xa7103c7c, 0x15ea281d,
44        0x84c413be, 0xf39dff5f, 0x6277eb00 } ,
45    { 0xd151d6a1, 0x402bc242, 0xaf05ade3, 0x1ddf9984, 0x8cb98525,
46        0xfb9370c6, 0x6a6d5c67, 0xd9474808 } ,
47    { 0x482133a9, 0xb6fb1f4a, 0x25d50aeb, 0x94aef68c, 0x0388e22d,
48        0x7262cdce, 0xe13cb96f, 0x5016a510 } ,
49    { 0xbef090b1, 0x2dca7c52, 0x9ca467f3, 0x0b7e5394, 0x7a583f35,
50        0xe9322ad6, 0x580c1677, 0xc6e60218 } ,
51    { 0x35bfedb9, 0xa499d95a, 0x1373c4fb, 0x824db09c, 0xf1279c3d,
52        0x600187de, 0xcedb737f, 0x3db55f20 } ,
53    { 0xac8f4ac1, 0x1b693662, 0x8a432203, 0xf91d0da4, 0x67f6f945,
54        0xd6d0e4e6, 0x45aad087, 0xb484bc28 } ,
55    { 0x235ea7c9, 0x9238936a, 0x01127f0b, 0x6fec6aac, 0xdec6564d,
56        0x4da041ee, 0xbc7a2d8f, 0x2b541930 } ,
57    { 0x9a2e04d1, 0x0907f072, 0x77e1dc13, 0xe6bbc7b4, 0x5595b355,
58        0xc46f9ef6, 0x33498a97, 0xa2237638 } ,
59    { 0x10fd61d9, 0x7fd74d7a, 0xeeb1391b, 0x5d8b24bc, 0xcc65105d,
60        0x3b3efbfe, 0xaa18e79f, 0x18f2d340 } ,
61    { 0x87ccbee1, 0xf6a6aa82, 0x65809623, 0xd45a81c4, 0x43346d65,
62        0xb20e5906, 0x20e844a7, 0x8fc23048 } ,
63    { 0xfe9c1be9, 0x6d76078a, 0xdc4ff32b, 0x4b29decc, 0xba03ca6d,
64        0x28ddb60e, 0x97b7a1af, 0x06918d50 } ,
65    { 0x756b78f1, 0xe4456492, 0x531f5033, 0xc1f93bd4, 0x30d32775,
66        0x9fad1316, 0x0e86feb7, 0x7d60ea58 } ,
67    { 0xec3ad5f9, 0x5b14c19a, 0xc9eead3b, 0x38c898dc, 0xa7a2847d,
68        0x167c701e, 0x85565bbf, 0xf4304760 } ,
69    { 0x630a3301, 0xd1e41ea2, 0x40be0a43, 0xaf97f5e4, 0x1e71e185,
70        0x8d4bcd26, 0xfc25b8c7, 0x6affa468 } ,
71    { 0xd9d99009, 0x48b37baa, 0xb78d674b, 0x266752ec, 0x95413e8d,
72        0x041b2a2e, 0x72f515cf, 0xe1cf0170 } ,
73    { 0x50a8ed11, 0xbf82d8b2, 0x2e5cc453, 0x9d36aff4, 0x0c109b95,
74        0x7aea8736, 0xe9c472d7, 0x589e5e78 } ,
75    { 0xc7784a19, 0x365235ba, 0xa52c215b, 0x14060cfc, 0x82dff89d,
76        0xf1b9e43e, 0x6093cfdf, 0xcf6dbb80 } ,
77    { 0x3e47a721, 0xad2192c2, 0x1bfb7e63, 0x8ad56a04, 0xf9af55a5,
78        0x68894146, 0xd7632ce7, 0x463d1888 } ,
79    { 0xb5170429, 0x23f0efca, 0x92cadb6b, 0x01a4c70c, 0x707eb2ad,
80        0xdf589e4e, 0x4e3289ef, 0xbd0c7590 } ,
81    { 0x2be66131, 0x9ac04cd2, 0x099a3873, 0x78742414, 0xe74e0fb5,
82        0x5627fb56, 0xc501e6f7, 0x33dbd298 } ,
83    { 0xa2b5be39, 0x118fa9da, 0x8069957b, 0xef43811c, 0x5e1d6cbd,
84        0xccf7585e, 0x3bd143ff, 0xaaab2fa0 } ,
85    { 0x19851b41, 0x885f06e2, 0xf738f283, 0x6612de24, 0xd4ecc9c5,
86        0x43c6b566, 0xb2a0a107, 0x217a8ca8 } ,
87    { 0x90547849, 0xff2e63ea, 0x6e084f8b, 0xdce23b2c, 0x4bbc26cd,
88        0xba96126e, 0x296ffe0f, 0x9849e9b0 } ,
89    { 0x0723d551, 0x75fdc0f2, 0xe4d7ac93, 0x53b19834, 0xc28b83d5,
90        0x31656f76, 0xa03f5b17, 0x0f1946b8 }
91};
92
93static const u8 Tr[4][8] = {
94    { 0x13, 0x04, 0x15, 0x06, 0x17, 0x08, 0x19, 0x0a } ,
95    { 0x1b, 0x0c, 0x1d, 0x0e, 0x1f, 0x10, 0x01, 0x12 } ,
96    { 0x03, 0x14, 0x05, 0x16, 0x07, 0x18, 0x09, 0x1a } ,
97    { 0x0b, 0x1c, 0x0d, 0x1e, 0x0f, 0x00, 0x11, 0x02 }
98};
99
100/* forward octave */
101static inline void W(u32 *key, unsigned int i)
102{
103    u32 I;
104    key[6] ^= F1(key[7], Tr[i % 4][0], Tm[i][0]);
105    key[5] ^= F2(key[6], Tr[i % 4][1], Tm[i][1]);
106    key[4] ^= F3(key[5], Tr[i % 4][2], Tm[i][2]);
107    key[3] ^= F1(key[4], Tr[i % 4][3], Tm[i][3]);
108    key[2] ^= F2(key[3], Tr[i % 4][4], Tm[i][4]);
109    key[1] ^= F3(key[2], Tr[i % 4][5], Tm[i][5]);
110    key[0] ^= F1(key[1], Tr[i % 4][6], Tm[i][6]);
111    key[7] ^= F2(key[0], Tr[i % 4][7], Tm[i][7]);
112}
113
114int __cast6_setkey(struct cast6_ctx *c, const u8 *in_key,
115           unsigned key_len, u32 *flags)
116{
117    int i;
118    u32 key[8];
119    __be32 p_key[8]; /* padded key */
120
121    if (key_len % 4 != 0) {
122        *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
123        return -EINVAL;
124    }
125
126    memset(p_key, 0, 32);
127    memcpy(p_key, in_key, key_len);
128
129    key[0] = be32_to_cpu(p_key[0]); /* A */
130    key[1] = be32_to_cpu(p_key[1]); /* B */
131    key[2] = be32_to_cpu(p_key[2]); /* C */
132    key[3] = be32_to_cpu(p_key[3]); /* D */
133    key[4] = be32_to_cpu(p_key[4]); /* E */
134    key[5] = be32_to_cpu(p_key[5]); /* F */
135    key[6] = be32_to_cpu(p_key[6]); /* G */
136    key[7] = be32_to_cpu(p_key[7]); /* H */
137
138    for (i = 0; i < 12; i++) {
139        W(key, 2 * i);
140        W(key, 2 * i + 1);
141
142        c->Kr[i][0] = key[0] & 0x1f;
143        c->Kr[i][1] = key[2] & 0x1f;
144        c->Kr[i][2] = key[4] & 0x1f;
145        c->Kr[i][3] = key[6] & 0x1f;
146
147        c->Km[i][0] = key[7];
148        c->Km[i][1] = key[5];
149        c->Km[i][2] = key[3];
150        c->Km[i][3] = key[1];
151    }
152
153    return 0;
154}
155EXPORT_SYMBOL_GPL(__cast6_setkey);
156
157int cast6_setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
158{
159    return __cast6_setkey(crypto_tfm_ctx(tfm), key, keylen,
160                  &tfm->crt_flags);
161}
162EXPORT_SYMBOL_GPL(cast6_setkey);
163
164/*forward quad round*/
165static inline void Q(u32 *block, u8 *Kr, u32 *Km)
166{
167    u32 I;
168    block[2] ^= F1(block[3], Kr[0], Km[0]);
169    block[1] ^= F2(block[2], Kr[1], Km[1]);
170    block[0] ^= F3(block[1], Kr[2], Km[2]);
171    block[3] ^= F1(block[0], Kr[3], Km[3]);
172}
173
174/*reverse quad round*/
175static inline void QBAR(u32 *block, u8 *Kr, u32 *Km)
176{
177    u32 I;
178    block[3] ^= F1(block[0], Kr[3], Km[3]);
179    block[0] ^= F3(block[1], Kr[2], Km[2]);
180    block[1] ^= F2(block[2], Kr[1], Km[1]);
181    block[2] ^= F1(block[3], Kr[0], Km[0]);
182}
183
184void __cast6_encrypt(struct cast6_ctx *c, u8 *outbuf, const u8 *inbuf)
185{
186    const __be32 *src = (const __be32 *)inbuf;
187    __be32 *dst = (__be32 *)outbuf;
188    u32 block[4];
189    u32 *Km;
190    u8 *Kr;
191
192    block[0] = be32_to_cpu(src[0]);
193    block[1] = be32_to_cpu(src[1]);
194    block[2] = be32_to_cpu(src[2]);
195    block[3] = be32_to_cpu(src[3]);
196
197    Km = c->Km[0]; Kr = c->Kr[0]; Q(block, Kr, Km);
198    Km = c->Km[1]; Kr = c->Kr[1]; Q(block, Kr, Km);
199    Km = c->Km[2]; Kr = c->Kr[2]; Q(block, Kr, Km);
200    Km = c->Km[3]; Kr = c->Kr[3]; Q(block, Kr, Km);
201    Km = c->Km[4]; Kr = c->Kr[4]; Q(block, Kr, Km);
202    Km = c->Km[5]; Kr = c->Kr[5]; Q(block, Kr, Km);
203    Km = c->Km[6]; Kr = c->Kr[6]; QBAR(block, Kr, Km);
204    Km = c->Km[7]; Kr = c->Kr[7]; QBAR(block, Kr, Km);
205    Km = c->Km[8]; Kr = c->Kr[8]; QBAR(block, Kr, Km);
206    Km = c->Km[9]; Kr = c->Kr[9]; QBAR(block, Kr, Km);
207    Km = c->Km[10]; Kr = c->Kr[10]; QBAR(block, Kr, Km);
208    Km = c->Km[11]; Kr = c->Kr[11]; QBAR(block, Kr, Km);
209
210    dst[0] = cpu_to_be32(block[0]);
211    dst[1] = cpu_to_be32(block[1]);
212    dst[2] = cpu_to_be32(block[2]);
213    dst[3] = cpu_to_be32(block[3]);
214}
215EXPORT_SYMBOL_GPL(__cast6_encrypt);
216
217static void cast6_encrypt(struct crypto_tfm *tfm, u8 *outbuf, const u8 *inbuf)
218{
219    __cast6_encrypt(crypto_tfm_ctx(tfm), outbuf, inbuf);
220}
221
222void __cast6_decrypt(struct cast6_ctx *c, u8 *outbuf, const u8 *inbuf)
223{
224    const __be32 *src = (const __be32 *)inbuf;
225    __be32 *dst = (__be32 *)outbuf;
226    u32 block[4];
227    u32 *Km;
228    u8 *Kr;
229
230    block[0] = be32_to_cpu(src[0]);
231    block[1] = be32_to_cpu(src[1]);
232    block[2] = be32_to_cpu(src[2]);
233    block[3] = be32_to_cpu(src[3]);
234
235    Km = c->Km[11]; Kr = c->Kr[11]; Q(block, Kr, Km);
236    Km = c->Km[10]; Kr = c->Kr[10]; Q(block, Kr, Km);
237    Km = c->Km[9]; Kr = c->Kr[9]; Q(block, Kr, Km);
238    Km = c->Km[8]; Kr = c->Kr[8]; Q(block, Kr, Km);
239    Km = c->Km[7]; Kr = c->Kr[7]; Q(block, Kr, Km);
240    Km = c->Km[6]; Kr = c->Kr[6]; Q(block, Kr, Km);
241    Km = c->Km[5]; Kr = c->Kr[5]; QBAR(block, Kr, Km);
242    Km = c->Km[4]; Kr = c->Kr[4]; QBAR(block, Kr, Km);
243    Km = c->Km[3]; Kr = c->Kr[3]; QBAR(block, Kr, Km);
244    Km = c->Km[2]; Kr = c->Kr[2]; QBAR(block, Kr, Km);
245    Km = c->Km[1]; Kr = c->Kr[1]; QBAR(block, Kr, Km);
246    Km = c->Km[0]; Kr = c->Kr[0]; QBAR(block, Kr, Km);
247
248    dst[0] = cpu_to_be32(block[0]);
249    dst[1] = cpu_to_be32(block[1]);
250    dst[2] = cpu_to_be32(block[2]);
251    dst[3] = cpu_to_be32(block[3]);
252}
253EXPORT_SYMBOL_GPL(__cast6_decrypt);
254
255static void cast6_decrypt(struct crypto_tfm *tfm, u8 *outbuf, const u8 *inbuf)
256{
257    __cast6_decrypt(crypto_tfm_ctx(tfm), outbuf, inbuf);
258}
259
260static struct crypto_alg alg = {
261    .cra_name = "cast6",
262    .cra_driver_name = "cast6-generic",
263    .cra_priority = 100,
264    .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
265    .cra_blocksize = CAST6_BLOCK_SIZE,
266    .cra_ctxsize = sizeof(struct cast6_ctx),
267    .cra_alignmask = 3,
268    .cra_module = THIS_MODULE,
269    .cra_u = {
270          .cipher = {
271                 .cia_min_keysize = CAST6_MIN_KEY_SIZE,
272                 .cia_max_keysize = CAST6_MAX_KEY_SIZE,
273                 .cia_setkey = cast6_setkey,
274                 .cia_encrypt = cast6_encrypt,
275                 .cia_decrypt = cast6_decrypt}
276          }
277};
278
279static int __init cast6_mod_init(void)
280{
281    return crypto_register_alg(&alg);
282}
283
284static void __exit cast6_mod_fini(void)
285{
286    crypto_unregister_alg(&alg);
287}
288
289module_init(cast6_mod_init);
290module_exit(cast6_mod_fini);
291
292MODULE_LICENSE("GPL");
293MODULE_DESCRIPTION("Cast6 Cipher Algorithm");
294MODULE_ALIAS("cast6");
295

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