1 /* $FreeBSD: src/sys/opencrypto/cast.c,v 1.4 2007/07/05 06:59:14 peter Exp $ */
2 /* $OpenBSD: cast.c,v 1.2 2000/06/06 06:49:47 deraadt Exp $ */
5 * Written by Steve Reid <sreid@sea-to-sky.net>
6 * 100% Public Domain - no warranty
10 #include <sys/types.h>
11 #include <opencrypto/cast.h>
12 #include <opencrypto/castsb.h>
14 /* Macros to access 8-bit bytes out of a 32-bit word */
15 #define U_INT8_Ta(x) ( (u_int8_t) (x>>24) )
16 #define U_INT8_Tb(x) ( (u_int8_t) ((x>>16)&255) )
17 #define U_INT8_Tc(x) ( (u_int8_t) ((x>>8)&255) )
18 #define U_INT8_Td(x) ( (u_int8_t) ((x)&255) )
20 /* Circular left shift */
21 #define ROL(x, n) ( ((x)<<(n)) | ((x)>>(32-(n))) )
23 /* CAST-128 uses three different round functions */
25 t = ROL(key->xkey[i] + r, key->xkey[i+16]); \
26 l ^= ((cast_sbox1[U_INT8_Ta(t)] ^ cast_sbox2[U_INT8_Tb(t)]) - \
27 cast_sbox3[U_INT8_Tc(t)]) + cast_sbox4[U_INT8_Td(t)];
29 t = ROL(key->xkey[i] ^ r, key->xkey[i+16]); \
30 l ^= ((cast_sbox1[U_INT8_Ta(t)] - cast_sbox2[U_INT8_Tb(t)]) + \
31 cast_sbox3[U_INT8_Tc(t)]) ^ cast_sbox4[U_INT8_Td(t)];
33 t = ROL(key->xkey[i] - r, key->xkey[i+16]); \
34 l ^= ((cast_sbox1[U_INT8_Ta(t)] + cast_sbox2[U_INT8_Tb(t)]) ^ \
35 cast_sbox3[U_INT8_Tc(t)]) - cast_sbox4[U_INT8_Td(t)];
38 /***** Encryption Function *****/
40 void cast_encrypt(cast_key
* key
, u_int8_t
* inblock
, u_int8_t
* outblock
)
44 /* Get inblock into l,r */
45 l
= ((u_int32_t
)inblock
[0] << 24) | ((u_int32_t
)inblock
[1] << 16) |
46 ((u_int32_t
)inblock
[2] << 8) | (u_int32_t
)inblock
[3];
47 r
= ((u_int32_t
)inblock
[4] << 24) | ((u_int32_t
)inblock
[5] << 16) |
48 ((u_int32_t
)inblock
[6] << 8) | (u_int32_t
)inblock
[7];
62 /* Only do full 16 rounds if key length > 80 bits */
63 if (key
->rounds
> 12) {
69 /* Put l,r into outblock */
70 outblock
[0] = U_INT8_Ta(r
);
71 outblock
[1] = U_INT8_Tb(r
);
72 outblock
[2] = U_INT8_Tc(r
);
73 outblock
[3] = U_INT8_Td(r
);
74 outblock
[4] = U_INT8_Ta(l
);
75 outblock
[5] = U_INT8_Tb(l
);
76 outblock
[6] = U_INT8_Tc(l
);
77 outblock
[7] = U_INT8_Td(l
);
83 /***** Decryption Function *****/
85 void cast_decrypt(cast_key
* key
, u_int8_t
* inblock
, u_int8_t
* outblock
)
89 /* Get inblock into l,r */
90 r
= ((u_int32_t
)inblock
[0] << 24) | ((u_int32_t
)inblock
[1] << 16) |
91 ((u_int32_t
)inblock
[2] << 8) | (u_int32_t
)inblock
[3];
92 l
= ((u_int32_t
)inblock
[4] << 24) | ((u_int32_t
)inblock
[5] << 16) |
93 ((u_int32_t
)inblock
[6] << 8) | (u_int32_t
)inblock
[7];
95 /* Only do full 16 rounds if key length > 80 bits */
96 if (key
->rounds
> 12) {
114 /* Put l,r into outblock */
115 outblock
[0] = U_INT8_Ta(l
);
116 outblock
[1] = U_INT8_Tb(l
);
117 outblock
[2] = U_INT8_Tc(l
);
118 outblock
[3] = U_INT8_Td(l
);
119 outblock
[4] = U_INT8_Ta(r
);
120 outblock
[5] = U_INT8_Tb(r
);
121 outblock
[6] = U_INT8_Tc(r
);
122 outblock
[7] = U_INT8_Td(r
);
128 /***** Key Schedual *****/
130 void cast_setkey(cast_key
* key
, u_int8_t
* rawkey
, int keybytes
)
132 u_int32_t t
[4] = {0, 0, 0, 0}, z
[4] = {0, 0, 0, 0}, x
[4];
135 /* Set number of rounds to 12 or 16, depending on key length */
136 key
->rounds
= (keybytes
<= 10 ? 12 : 16);
138 /* Copy key to workspace x */
139 for (i
= 0; i
< 4; i
++) {
141 if ((i
*4+0) < keybytes
) x
[i
] = (u_int32_t
)rawkey
[i
*4+0] << 24;
142 if ((i
*4+1) < keybytes
) x
[i
] |= (u_int32_t
)rawkey
[i
*4+1] << 16;
143 if ((i
*4+2) < keybytes
) x
[i
] |= (u_int32_t
)rawkey
[i
*4+2] << 8;
144 if ((i
*4+3) < keybytes
) x
[i
] |= (u_int32_t
)rawkey
[i
*4+3];
146 /* Generate 32 subkeys, four at a time */
147 for (i
= 0; i
< 32; i
+=4) {
150 t
[0] = z
[0] = x
[0] ^ cast_sbox5
[U_INT8_Tb(x
[3])] ^
151 cast_sbox6
[U_INT8_Td(x
[3])] ^ cast_sbox7
[U_INT8_Ta(x
[3])] ^
152 cast_sbox8
[U_INT8_Tc(x
[3])] ^ cast_sbox7
[U_INT8_Ta(x
[2])];
153 t
[1] = z
[1] = x
[2] ^ cast_sbox5
[U_INT8_Ta(z
[0])] ^
154 cast_sbox6
[U_INT8_Tc(z
[0])] ^ cast_sbox7
[U_INT8_Tb(z
[0])] ^
155 cast_sbox8
[U_INT8_Td(z
[0])] ^ cast_sbox8
[U_INT8_Tc(x
[2])];
156 t
[2] = z
[2] = x
[3] ^ cast_sbox5
[U_INT8_Td(z
[1])] ^
157 cast_sbox6
[U_INT8_Tc(z
[1])] ^ cast_sbox7
[U_INT8_Tb(z
[1])] ^
158 cast_sbox8
[U_INT8_Ta(z
[1])] ^ cast_sbox5
[U_INT8_Tb(x
[2])];
159 t
[3] = z
[3] = x
[1] ^ cast_sbox5
[U_INT8_Tc(z
[2])] ^
160 cast_sbox6
[U_INT8_Tb(z
[2])] ^ cast_sbox7
[U_INT8_Td(z
[2])] ^
161 cast_sbox8
[U_INT8_Ta(z
[2])] ^ cast_sbox6
[U_INT8_Td(x
[2])];
164 t
[0] = x
[0] = z
[2] ^ cast_sbox5
[U_INT8_Tb(z
[1])] ^
165 cast_sbox6
[U_INT8_Td(z
[1])] ^ cast_sbox7
[U_INT8_Ta(z
[1])] ^
166 cast_sbox8
[U_INT8_Tc(z
[1])] ^ cast_sbox7
[U_INT8_Ta(z
[0])];
167 t
[1] = x
[1] = z
[0] ^ cast_sbox5
[U_INT8_Ta(x
[0])] ^
168 cast_sbox6
[U_INT8_Tc(x
[0])] ^ cast_sbox7
[U_INT8_Tb(x
[0])] ^
169 cast_sbox8
[U_INT8_Td(x
[0])] ^ cast_sbox8
[U_INT8_Tc(z
[0])];
170 t
[2] = x
[2] = z
[1] ^ cast_sbox5
[U_INT8_Td(x
[1])] ^
171 cast_sbox6
[U_INT8_Tc(x
[1])] ^ cast_sbox7
[U_INT8_Tb(x
[1])] ^
172 cast_sbox8
[U_INT8_Ta(x
[1])] ^ cast_sbox5
[U_INT8_Tb(z
[0])];
173 t
[3] = x
[3] = z
[3] ^ cast_sbox5
[U_INT8_Tc(x
[2])] ^
174 cast_sbox6
[U_INT8_Tb(x
[2])] ^ cast_sbox7
[U_INT8_Td(x
[2])] ^
175 cast_sbox8
[U_INT8_Ta(x
[2])] ^ cast_sbox6
[U_INT8_Td(z
[0])];
181 key
->xkey
[i
+0] = cast_sbox5
[U_INT8_Ta(t
[2])] ^ cast_sbox6
[U_INT8_Tb(t
[2])] ^
182 cast_sbox7
[U_INT8_Td(t
[1])] ^ cast_sbox8
[U_INT8_Tc(t
[1])];
183 key
->xkey
[i
+1] = cast_sbox5
[U_INT8_Tc(t
[2])] ^ cast_sbox6
[U_INT8_Td(t
[2])] ^
184 cast_sbox7
[U_INT8_Tb(t
[1])] ^ cast_sbox8
[U_INT8_Ta(t
[1])];
185 key
->xkey
[i
+2] = cast_sbox5
[U_INT8_Ta(t
[3])] ^ cast_sbox6
[U_INT8_Tb(t
[3])] ^
186 cast_sbox7
[U_INT8_Td(t
[0])] ^ cast_sbox8
[U_INT8_Tc(t
[0])];
187 key
->xkey
[i
+3] = cast_sbox5
[U_INT8_Tc(t
[3])] ^ cast_sbox6
[U_INT8_Td(t
[3])] ^
188 cast_sbox7
[U_INT8_Tb(t
[0])] ^ cast_sbox8
[U_INT8_Ta(t
[0])];
192 key
->xkey
[i
+0] = cast_sbox5
[U_INT8_Td(t
[0])] ^ cast_sbox6
[U_INT8_Tc(t
[0])] ^
193 cast_sbox7
[U_INT8_Ta(t
[3])] ^ cast_sbox8
[U_INT8_Tb(t
[3])];
194 key
->xkey
[i
+1] = cast_sbox5
[U_INT8_Tb(t
[0])] ^ cast_sbox6
[U_INT8_Ta(t
[0])] ^
195 cast_sbox7
[U_INT8_Tc(t
[3])] ^ cast_sbox8
[U_INT8_Td(t
[3])];
196 key
->xkey
[i
+2] = cast_sbox5
[U_INT8_Td(t
[1])] ^ cast_sbox6
[U_INT8_Tc(t
[1])] ^
197 cast_sbox7
[U_INT8_Ta(t
[2])] ^ cast_sbox8
[U_INT8_Tb(t
[2])];
198 key
->xkey
[i
+3] = cast_sbox5
[U_INT8_Tb(t
[1])] ^ cast_sbox6
[U_INT8_Ta(t
[1])] ^
199 cast_sbox7
[U_INT8_Tc(t
[2])] ^ cast_sbox8
[U_INT8_Td(t
[2])];
204 key
->xkey
[i
+0] ^= cast_sbox5
[U_INT8_Tc(z
[0])];
205 key
->xkey
[i
+1] ^= cast_sbox6
[U_INT8_Tc(z
[1])];
206 key
->xkey
[i
+2] ^= cast_sbox7
[U_INT8_Tb(z
[2])];
207 key
->xkey
[i
+3] ^= cast_sbox8
[U_INT8_Ta(z
[3])];
210 key
->xkey
[i
+0] ^= cast_sbox5
[U_INT8_Ta(x
[2])];
211 key
->xkey
[i
+1] ^= cast_sbox6
[U_INT8_Tb(x
[3])];
212 key
->xkey
[i
+2] ^= cast_sbox7
[U_INT8_Td(x
[0])];
213 key
->xkey
[i
+3] ^= cast_sbox8
[U_INT8_Td(x
[1])];
216 key
->xkey
[i
+0] ^= cast_sbox5
[U_INT8_Tb(z
[2])];
217 key
->xkey
[i
+1] ^= cast_sbox6
[U_INT8_Ta(z
[3])];
218 key
->xkey
[i
+2] ^= cast_sbox7
[U_INT8_Tc(z
[0])];
219 key
->xkey
[i
+3] ^= cast_sbox8
[U_INT8_Tc(z
[1])];
222 key
->xkey
[i
+0] ^= cast_sbox5
[U_INT8_Td(x
[0])];
223 key
->xkey
[i
+1] ^= cast_sbox6
[U_INT8_Td(x
[1])];
224 key
->xkey
[i
+2] ^= cast_sbox7
[U_INT8_Ta(x
[2])];
225 key
->xkey
[i
+3] ^= cast_sbox8
[U_INT8_Tb(x
[3])];
229 key
->xkey
[i
+0] &= 31;
230 key
->xkey
[i
+1] &= 31;
231 key
->xkey
[i
+2] &= 31;
232 key
->xkey
[i
+3] &= 31;
236 for (i
= 0; i
< 4; i
++) {
237 t
[i
] = x
[i
] = z
[i
] = 0;