1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Kernel cryptographic api.
3 * cast6.c - Cast6 cipher algorithm [rfc2612].
5 * CAST-256 (*cast6*) is a DES like Substitution-Permutation Network (SPN)
6 * cryptosystem built upon the CAST-128 (*cast5*) [rfc2144] encryption
9 * Copyright (C) 2003 Kartikey Mahendra Bhatt <kartik_me@hotmail.com>.
13 #include <asm/byteorder.h>
14 #include <linux/init.h>
15 #include <linux/crypto.h>
16 #include <linux/module.h>
17 #include <linux/errno.h>
18 #include <linux/string.h>
19 #include <linux/types.h>
20 #include <crypto/cast6.h>
27 #define F1(D, r, m) ((I = ((m) + (D))), (I = rol32(I, (r))), \
28 (((s1[I >> 24] ^ s2[(I>>16)&0xff]) - s3[(I>>8)&0xff]) + s4[I&0xff]))
29 #define F2(D, r, m) ((I = ((m) ^ (D))), (I = rol32(I, (r))), \
30 (((s1[I >> 24] - s2[(I>>16)&0xff]) + s3[(I>>8)&0xff]) ^ s4[I&0xff]))
31 #define F3(D, r, m) ((I = ((m) - (D))), (I = rol32(I, (r))), \
32 (((s1[I >> 24] + s2[(I>>16)&0xff]) ^ s3[(I>>8)&0xff]) - s4[I&0xff]))
34 static const u32 Tm
[24][8] = {
35 { 0x5a827999, 0xc95c653a, 0x383650db, 0xa7103c7c, 0x15ea281d,
36 0x84c413be, 0xf39dff5f, 0x6277eb00 } ,
37 { 0xd151d6a1, 0x402bc242, 0xaf05ade3, 0x1ddf9984, 0x8cb98525,
38 0xfb9370c6, 0x6a6d5c67, 0xd9474808 } ,
39 { 0x482133a9, 0xb6fb1f4a, 0x25d50aeb, 0x94aef68c, 0x0388e22d,
40 0x7262cdce, 0xe13cb96f, 0x5016a510 } ,
41 { 0xbef090b1, 0x2dca7c52, 0x9ca467f3, 0x0b7e5394, 0x7a583f35,
42 0xe9322ad6, 0x580c1677, 0xc6e60218 } ,
43 { 0x35bfedb9, 0xa499d95a, 0x1373c4fb, 0x824db09c, 0xf1279c3d,
44 0x600187de, 0xcedb737f, 0x3db55f20 } ,
45 { 0xac8f4ac1, 0x1b693662, 0x8a432203, 0xf91d0da4, 0x67f6f945,
46 0xd6d0e4e6, 0x45aad087, 0xb484bc28 } ,
47 { 0x235ea7c9, 0x9238936a, 0x01127f0b, 0x6fec6aac, 0xdec6564d,
48 0x4da041ee, 0xbc7a2d8f, 0x2b541930 } ,
49 { 0x9a2e04d1, 0x0907f072, 0x77e1dc13, 0xe6bbc7b4, 0x5595b355,
50 0xc46f9ef6, 0x33498a97, 0xa2237638 } ,
51 { 0x10fd61d9, 0x7fd74d7a, 0xeeb1391b, 0x5d8b24bc, 0xcc65105d,
52 0x3b3efbfe, 0xaa18e79f, 0x18f2d340 } ,
53 { 0x87ccbee1, 0xf6a6aa82, 0x65809623, 0xd45a81c4, 0x43346d65,
54 0xb20e5906, 0x20e844a7, 0x8fc23048 } ,
55 { 0xfe9c1be9, 0x6d76078a, 0xdc4ff32b, 0x4b29decc, 0xba03ca6d,
56 0x28ddb60e, 0x97b7a1af, 0x06918d50 } ,
57 { 0x756b78f1, 0xe4456492, 0x531f5033, 0xc1f93bd4, 0x30d32775,
58 0x9fad1316, 0x0e86feb7, 0x7d60ea58 } ,
59 { 0xec3ad5f9, 0x5b14c19a, 0xc9eead3b, 0x38c898dc, 0xa7a2847d,
60 0x167c701e, 0x85565bbf, 0xf4304760 } ,
61 { 0x630a3301, 0xd1e41ea2, 0x40be0a43, 0xaf97f5e4, 0x1e71e185,
62 0x8d4bcd26, 0xfc25b8c7, 0x6affa468 } ,
63 { 0xd9d99009, 0x48b37baa, 0xb78d674b, 0x266752ec, 0x95413e8d,
64 0x041b2a2e, 0x72f515cf, 0xe1cf0170 } ,
65 { 0x50a8ed11, 0xbf82d8b2, 0x2e5cc453, 0x9d36aff4, 0x0c109b95,
66 0x7aea8736, 0xe9c472d7, 0x589e5e78 } ,
67 { 0xc7784a19, 0x365235ba, 0xa52c215b, 0x14060cfc, 0x82dff89d,
68 0xf1b9e43e, 0x6093cfdf, 0xcf6dbb80 } ,
69 { 0x3e47a721, 0xad2192c2, 0x1bfb7e63, 0x8ad56a04, 0xf9af55a5,
70 0x68894146, 0xd7632ce7, 0x463d1888 } ,
71 { 0xb5170429, 0x23f0efca, 0x92cadb6b, 0x01a4c70c, 0x707eb2ad,
72 0xdf589e4e, 0x4e3289ef, 0xbd0c7590 } ,
73 { 0x2be66131, 0x9ac04cd2, 0x099a3873, 0x78742414, 0xe74e0fb5,
74 0x5627fb56, 0xc501e6f7, 0x33dbd298 } ,
75 { 0xa2b5be39, 0x118fa9da, 0x8069957b, 0xef43811c, 0x5e1d6cbd,
76 0xccf7585e, 0x3bd143ff, 0xaaab2fa0 } ,
77 { 0x19851b41, 0x885f06e2, 0xf738f283, 0x6612de24, 0xd4ecc9c5,
78 0x43c6b566, 0xb2a0a107, 0x217a8ca8 } ,
79 { 0x90547849, 0xff2e63ea, 0x6e084f8b, 0xdce23b2c, 0x4bbc26cd,
80 0xba96126e, 0x296ffe0f, 0x9849e9b0 } ,
81 { 0x0723d551, 0x75fdc0f2, 0xe4d7ac93, 0x53b19834, 0xc28b83d5,
82 0x31656f76, 0xa03f5b17, 0x0f1946b8 }
85 static const u8 Tr
[4][8] = {
86 { 0x13, 0x04, 0x15, 0x06, 0x17, 0x08, 0x19, 0x0a } ,
87 { 0x1b, 0x0c, 0x1d, 0x0e, 0x1f, 0x10, 0x01, 0x12 } ,
88 { 0x03, 0x14, 0x05, 0x16, 0x07, 0x18, 0x09, 0x1a } ,
89 { 0x0b, 0x1c, 0x0d, 0x1e, 0x0f, 0x00, 0x11, 0x02 }
93 static inline void W(u32
*key
, unsigned int i
)
96 key
[6] ^= F1(key
[7], Tr
[i
% 4][0], Tm
[i
][0]);
97 key
[5] ^= F2(key
[6], Tr
[i
% 4][1], Tm
[i
][1]);
98 key
[4] ^= F3(key
[5], Tr
[i
% 4][2], Tm
[i
][2]);
99 key
[3] ^= F1(key
[4], Tr
[i
% 4][3], Tm
[i
][3]);
100 key
[2] ^= F2(key
[3], Tr
[i
% 4][4], Tm
[i
][4]);
101 key
[1] ^= F3(key
[2], Tr
[i
% 4][5], Tm
[i
][5]);
102 key
[0] ^= F1(key
[1], Tr
[i
% 4][6], Tm
[i
][6]);
103 key
[7] ^= F2(key
[0], Tr
[i
% 4][7], Tm
[i
][7]);
106 int __cast6_setkey(struct cast6_ctx
*c
, const u8
*in_key
,
107 unsigned key_len
, u32
*flags
)
111 __be32 p_key
[8]; /* padded key */
113 if (key_len
% 4 != 0) {
114 *flags
|= CRYPTO_TFM_RES_BAD_KEY_LEN
;
118 memset(p_key
, 0, 32);
119 memcpy(p_key
, in_key
, key_len
);
121 key
[0] = be32_to_cpu(p_key
[0]); /* A */
122 key
[1] = be32_to_cpu(p_key
[1]); /* B */
123 key
[2] = be32_to_cpu(p_key
[2]); /* C */
124 key
[3] = be32_to_cpu(p_key
[3]); /* D */
125 key
[4] = be32_to_cpu(p_key
[4]); /* E */
126 key
[5] = be32_to_cpu(p_key
[5]); /* F */
127 key
[6] = be32_to_cpu(p_key
[6]); /* G */
128 key
[7] = be32_to_cpu(p_key
[7]); /* H */
130 for (i
= 0; i
< 12; i
++) {
134 c
->Kr
[i
][0] = key
[0] & 0x1f;
135 c
->Kr
[i
][1] = key
[2] & 0x1f;
136 c
->Kr
[i
][2] = key
[4] & 0x1f;
137 c
->Kr
[i
][3] = key
[6] & 0x1f;
139 c
->Km
[i
][0] = key
[7];
140 c
->Km
[i
][1] = key
[5];
141 c
->Km
[i
][2] = key
[3];
142 c
->Km
[i
][3] = key
[1];
147 EXPORT_SYMBOL_GPL(__cast6_setkey
);
149 int cast6_setkey(struct crypto_tfm
*tfm
, const u8
*key
, unsigned int keylen
)
151 return __cast6_setkey(crypto_tfm_ctx(tfm
), key
, keylen
,
154 EXPORT_SYMBOL_GPL(cast6_setkey
);
156 /*forward quad round*/
157 static inline void Q(u32
*block
, u8
*Kr
, u32
*Km
)
160 block
[2] ^= F1(block
[3], Kr
[0], Km
[0]);
161 block
[1] ^= F2(block
[2], Kr
[1], Km
[1]);
162 block
[0] ^= F3(block
[1], Kr
[2], Km
[2]);
163 block
[3] ^= F1(block
[0], Kr
[3], Km
[3]);
166 /*reverse quad round*/
167 static inline void QBAR(u32
*block
, u8
*Kr
, u32
*Km
)
170 block
[3] ^= F1(block
[0], Kr
[3], Km
[3]);
171 block
[0] ^= F3(block
[1], Kr
[2], Km
[2]);
172 block
[1] ^= F2(block
[2], Kr
[1], Km
[1]);
173 block
[2] ^= F1(block
[3], Kr
[0], Km
[0]);
176 void __cast6_encrypt(struct cast6_ctx
*c
, u8
*outbuf
, const u8
*inbuf
)
178 const __be32
*src
= (const __be32
*)inbuf
;
179 __be32
*dst
= (__be32
*)outbuf
;
184 block
[0] = be32_to_cpu(src
[0]);
185 block
[1] = be32_to_cpu(src
[1]);
186 block
[2] = be32_to_cpu(src
[2]);
187 block
[3] = be32_to_cpu(src
[3]);
189 Km
= c
->Km
[0]; Kr
= c
->Kr
[0]; Q(block
, Kr
, Km
);
190 Km
= c
->Km
[1]; Kr
= c
->Kr
[1]; Q(block
, Kr
, Km
);
191 Km
= c
->Km
[2]; Kr
= c
->Kr
[2]; Q(block
, Kr
, Km
);
192 Km
= c
->Km
[3]; Kr
= c
->Kr
[3]; Q(block
, Kr
, Km
);
193 Km
= c
->Km
[4]; Kr
= c
->Kr
[4]; Q(block
, Kr
, Km
);
194 Km
= c
->Km
[5]; Kr
= c
->Kr
[5]; Q(block
, Kr
, Km
);
195 Km
= c
->Km
[6]; Kr
= c
->Kr
[6]; QBAR(block
, Kr
, Km
);
196 Km
= c
->Km
[7]; Kr
= c
->Kr
[7]; QBAR(block
, Kr
, Km
);
197 Km
= c
->Km
[8]; Kr
= c
->Kr
[8]; QBAR(block
, Kr
, Km
);
198 Km
= c
->Km
[9]; Kr
= c
->Kr
[9]; QBAR(block
, Kr
, Km
);
199 Km
= c
->Km
[10]; Kr
= c
->Kr
[10]; QBAR(block
, Kr
, Km
);
200 Km
= c
->Km
[11]; Kr
= c
->Kr
[11]; QBAR(block
, Kr
, Km
);
202 dst
[0] = cpu_to_be32(block
[0]);
203 dst
[1] = cpu_to_be32(block
[1]);
204 dst
[2] = cpu_to_be32(block
[2]);
205 dst
[3] = cpu_to_be32(block
[3]);
207 EXPORT_SYMBOL_GPL(__cast6_encrypt
);
209 static void cast6_encrypt(struct crypto_tfm
*tfm
, u8
*outbuf
, const u8
*inbuf
)
211 __cast6_encrypt(crypto_tfm_ctx(tfm
), outbuf
, inbuf
);
214 void __cast6_decrypt(struct cast6_ctx
*c
, u8
*outbuf
, const u8
*inbuf
)
216 const __be32
*src
= (const __be32
*)inbuf
;
217 __be32
*dst
= (__be32
*)outbuf
;
222 block
[0] = be32_to_cpu(src
[0]);
223 block
[1] = be32_to_cpu(src
[1]);
224 block
[2] = be32_to_cpu(src
[2]);
225 block
[3] = be32_to_cpu(src
[3]);
227 Km
= c
->Km
[11]; Kr
= c
->Kr
[11]; Q(block
, Kr
, Km
);
228 Km
= c
->Km
[10]; Kr
= c
->Kr
[10]; Q(block
, Kr
, Km
);
229 Km
= c
->Km
[9]; Kr
= c
->Kr
[9]; Q(block
, Kr
, Km
);
230 Km
= c
->Km
[8]; Kr
= c
->Kr
[8]; Q(block
, Kr
, Km
);
231 Km
= c
->Km
[7]; Kr
= c
->Kr
[7]; Q(block
, Kr
, Km
);
232 Km
= c
->Km
[6]; Kr
= c
->Kr
[6]; Q(block
, Kr
, Km
);
233 Km
= c
->Km
[5]; Kr
= c
->Kr
[5]; QBAR(block
, Kr
, Km
);
234 Km
= c
->Km
[4]; Kr
= c
->Kr
[4]; QBAR(block
, Kr
, Km
);
235 Km
= c
->Km
[3]; Kr
= c
->Kr
[3]; QBAR(block
, Kr
, Km
);
236 Km
= c
->Km
[2]; Kr
= c
->Kr
[2]; QBAR(block
, Kr
, Km
);
237 Km
= c
->Km
[1]; Kr
= c
->Kr
[1]; QBAR(block
, Kr
, Km
);
238 Km
= c
->Km
[0]; Kr
= c
->Kr
[0]; QBAR(block
, Kr
, Km
);
240 dst
[0] = cpu_to_be32(block
[0]);
241 dst
[1] = cpu_to_be32(block
[1]);
242 dst
[2] = cpu_to_be32(block
[2]);
243 dst
[3] = cpu_to_be32(block
[3]);
245 EXPORT_SYMBOL_GPL(__cast6_decrypt
);
247 static void cast6_decrypt(struct crypto_tfm
*tfm
, u8
*outbuf
, const u8
*inbuf
)
249 __cast6_decrypt(crypto_tfm_ctx(tfm
), outbuf
, inbuf
);
252 static struct crypto_alg alg
= {
254 .cra_driver_name
= "cast6-generic",
256 .cra_flags
= CRYPTO_ALG_TYPE_CIPHER
,
257 .cra_blocksize
= CAST6_BLOCK_SIZE
,
258 .cra_ctxsize
= sizeof(struct cast6_ctx
),
260 .cra_module
= THIS_MODULE
,
263 .cia_min_keysize
= CAST6_MIN_KEY_SIZE
,
264 .cia_max_keysize
= CAST6_MAX_KEY_SIZE
,
265 .cia_setkey
= cast6_setkey
,
266 .cia_encrypt
= cast6_encrypt
,
267 .cia_decrypt
= cast6_decrypt
}
271 static int __init
cast6_mod_init(void)
273 return crypto_register_alg(&alg
);
276 static void __exit
cast6_mod_fini(void)
278 crypto_unregister_alg(&alg
);
281 subsys_initcall(cast6_mod_init
);
282 module_exit(cast6_mod_fini
);
284 MODULE_LICENSE("GPL");
285 MODULE_DESCRIPTION("Cast6 Cipher Algorithm");
286 MODULE_ALIAS_CRYPTO("cast6");
287 MODULE_ALIAS_CRYPTO("cast6-generic");