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Linux/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 
 42 static 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 
 93 static 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 */
101 static 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 
114 int __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 }
155 EXPORT_SYMBOL_GPL(__cast6_setkey);
156 
157 int 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 }
162 EXPORT_SYMBOL_GPL(cast6_setkey);
163 
164 /*forward quad round*/
165 static 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*/
175 static 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 
184 void __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 }
215 EXPORT_SYMBOL_GPL(__cast6_encrypt);
216 
217 static void cast6_encrypt(struct crypto_tfm *tfm, u8 *outbuf, const u8 *inbuf)
218 {
219         __cast6_encrypt(crypto_tfm_ctx(tfm), outbuf, inbuf);
220 }
221 
222 void __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 }
253 EXPORT_SYMBOL_GPL(__cast6_decrypt);
254 
255 static void cast6_decrypt(struct crypto_tfm *tfm, u8 *outbuf, const u8 *inbuf)
256 {
257         __cast6_decrypt(crypto_tfm_ctx(tfm), outbuf, inbuf);
258 }
259 
260 static 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 
279 static int __init cast6_mod_init(void)
280 {
281         return crypto_register_alg(&alg);
282 }
283 
284 static void __exit cast6_mod_fini(void)
285 {
286         crypto_unregister_alg(&alg);
287 }
288 
289 module_init(cast6_mod_init);
290 module_exit(cast6_mod_fini);
291 
292 MODULE_LICENSE("GPL");
293 MODULE_DESCRIPTION("Cast6 Cipher Algorithm");
294 MODULE_ALIAS_CRYPTO("cast6");
295 MODULE_ALIAS_CRYPTO("cast6-generic");
296 

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