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;