1 /* $NetBSD: cast128.c,v 1.7 2003/08/26 20:03:57 thorpej Exp $ */
2 /* $OpenBSD: cast.c,v 1.2 2000/06/06 06:49:47 deraadt Exp $ */
3
4 /*
5 * CAST-128 in C
6 * Written by Steve Reid <sreid@sea-to-sky.net>
7 * 100% Public Domain - no warranty
8 * Released 1997.10.11
9 */
10
11 #include <sys/cdefs.h>
12 __KERNEL_RCSID(0, "$NetBSD: cast128.c,v 1.7 2003/08/26 20:03:57 thorpej Exp $");
13
14 #include <sys/types.h>
15 #include <crypto/cast128/cast128.h>
16 #include <crypto/cast128/cast128sb.h>
17
18 /* Macros to access 8-bit bytes out of a 32-bit word */
19 #define U_INT8_Ta(x) ( (u_int8_t) (x>>24) )
20 #define U_INT8_Tb(x) ( (u_int8_t) ((x>>16)&255) )
21 #define U_INT8_Tc(x) ( (u_int8_t) ((x>>8)&255) )
22 #define U_INT8_Td(x) ( (u_int8_t) ((x)&255) )
23
24 /* Circular left shift */
25 #define ROL(x, n) ( ((x)<<(n)) | ((x)>>(32-(n))) )
26
27 /* CAST-128 uses three different round functions */
28 #define F1(l, r, i) \
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)];
32 #define F2(l, r, i) \
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)];
36 #define F3(l, r, i) \
37 t = ROL(key->xkey[i] - r, key->xkey[i+16]); \
38 l ^= ((cast_sbox1[U_INT8_Ta(t)] + cast_sbox2[U_INT8_Tb(t)]) ^ \
39 cast_sbox3[U_INT8_Tc(t)]) - cast_sbox4[U_INT8_Td(t)];
40
41
42 /***** Encryption Function *****/
43
44 void cast128_encrypt(const cast128_key* key, const u_int8_t* inblock,
45 u_int8_t* outblock)
46 {
47 u_int32_t t, l, r;
48
49 /* Get inblock into l,r */
50 l = ((u_int32_t)inblock[0] << 24) | ((u_int32_t)inblock[1] << 16) |
51 ((u_int32_t)inblock[2] << 8) | (u_int32_t)inblock[3];
52 r = ((u_int32_t)inblock[4] << 24) | ((u_int32_t)inblock[5] << 16) |
53 ((u_int32_t)inblock[6] << 8) | (u_int32_t)inblock[7];
54 /* Do the work */
55 F1(l, r, 0);
56 F2(r, l, 1);
57 F3(l, r, 2);
58 F1(r, l, 3);
59 F2(l, r, 4);
60 F3(r, l, 5);
61 F1(l, r, 6);
62 F2(r, l, 7);
63 F3(l, r, 8);
64 F1(r, l, 9);
65 F2(l, r, 10);
66 F3(r, l, 11);
67 /* Only do full 16 rounds if key length > 80 bits */
68 if (key->rounds > 12) {
69 F1(l, r, 12);
70 F2(r, l, 13);
71 F3(l, r, 14);
72 F1(r, l, 15);
73 }
74 /* Put l,r into outblock */
75 outblock[0] = U_INT8_Ta(r);
76 outblock[1] = U_INT8_Tb(r);
77 outblock[2] = U_INT8_Tc(r);
78 outblock[3] = U_INT8_Td(r);
79 outblock[4] = U_INT8_Ta(l);
80 outblock[5] = U_INT8_Tb(l);
81 outblock[6] = U_INT8_Tc(l);
82 outblock[7] = U_INT8_Td(l);
83 /* Wipe clean */
84 t = l = r = 0;
85 }
86
87
88 /***** Decryption Function *****/
89
90 void cast128_decrypt(const cast128_key* key, const u_int8_t* inblock,
91 u_int8_t* outblock)
92 {
93 u_int32_t t, l, r;
94
95 /* Get inblock into l,r */
96 r = ((u_int32_t)inblock[0] << 24) | ((u_int32_t)inblock[1] << 16) |
97 ((u_int32_t)inblock[2] << 8) | (u_int32_t)inblock[3];
98 l = ((u_int32_t)inblock[4] << 24) | ((u_int32_t)inblock[5] << 16) |
99 ((u_int32_t)inblock[6] << 8) | (u_int32_t)inblock[7];
100 /* Do the work */
101 /* Only do full 16 rounds if key length > 80 bits */
102 if (key->rounds > 12) {
103 F1(r, l, 15);
104 F3(l, r, 14);
105 F2(r, l, 13);
106 F1(l, r, 12);
107 }
108 F3(r, l, 11);
109 F2(l, r, 10);
110 F1(r, l, 9);
111 F3(l, r, 8);
112 F2(r, l, 7);
113 F1(l, r, 6);
114 F3(r, l, 5);
115 F2(l, r, 4);
116 F1(r, l, 3);
117 F3(l, r, 2);
118 F2(r, l, 1);
119 F1(l, r, 0);
120 /* Put l,r into outblock */
121 outblock[0] = U_INT8_Ta(l);
122 outblock[1] = U_INT8_Tb(l);
123 outblock[2] = U_INT8_Tc(l);
124 outblock[3] = U_INT8_Td(l);
125 outblock[4] = U_INT8_Ta(r);
126 outblock[5] = U_INT8_Tb(r);
127 outblock[6] = U_INT8_Tc(r);
128 outblock[7] = U_INT8_Td(r);
129 /* Wipe clean */
130 t = l = r = 0;
131 }
132
133
134 /***** Key Schedual *****/
135
136 void cast128_setkey(cast128_key* key, const u_int8_t* rawkey, int keybytes)
137 {
138 u_int32_t t[4], z[4], x[4];
139 int i;
140
141 /* Set number of rounds to 12 or 16, depending on key length */
142 key->rounds = (keybytes <= 10 ? 12 : 16);
143
144 /* Copy key to workspace x */
145 for (i = 0; i < 4; i++) {
146 x[i] = 0;
147 if ((i*4+0) < keybytes) x[i] = (u_int32_t)rawkey[i*4+0] << 24;
148 if ((i*4+1) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+1] << 16;
149 if ((i*4+2) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+2] << 8;
150 if ((i*4+3) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+3];
151 }
152 /* Generate 32 subkeys, four at a time */
153 for (i = 0; i < 32; i+=4) {
154 switch (i & 4) {
155 case 0:
156 t[0] = z[0] = x[0] ^ cast_sbox5[U_INT8_Tb(x[3])] ^
157 cast_sbox6[U_INT8_Td(x[3])] ^ cast_sbox7[U_INT8_Ta(x[3])] ^
158 cast_sbox8[U_INT8_Tc(x[3])] ^ cast_sbox7[U_INT8_Ta(x[2])];
159 t[1] = z[1] = x[2] ^ cast_sbox5[U_INT8_Ta(z[0])] ^
160 cast_sbox6[U_INT8_Tc(z[0])] ^ cast_sbox7[U_INT8_Tb(z[0])] ^
161 cast_sbox8[U_INT8_Td(z[0])] ^ cast_sbox8[U_INT8_Tc(x[2])];
162 t[2] = z[2] = x[3] ^ cast_sbox5[U_INT8_Td(z[1])] ^
163 cast_sbox6[U_INT8_Tc(z[1])] ^ cast_sbox7[U_INT8_Tb(z[1])] ^
164 cast_sbox8[U_INT8_Ta(z[1])] ^ cast_sbox5[U_INT8_Tb(x[2])];
165 t[3] = z[3] = x[1] ^ cast_sbox5[U_INT8_Tc(z[2])] ^
166 cast_sbox6[U_INT8_Tb(z[2])] ^ cast_sbox7[U_INT8_Td(z[2])] ^
167 cast_sbox8[U_INT8_Ta(z[2])] ^ cast_sbox6[U_INT8_Td(x[2])];
168 break;
169 case 4:
170 t[0] = x[0] = z[2] ^ cast_sbox5[U_INT8_Tb(z[1])] ^
171 cast_sbox6[U_INT8_Td(z[1])] ^ cast_sbox7[U_INT8_Ta(z[1])] ^
172 cast_sbox8[U_INT8_Tc(z[1])] ^ cast_sbox7[U_INT8_Ta(z[0])];
173 t[1] = x[1] = z[0] ^ cast_sbox5[U_INT8_Ta(x[0])] ^
174 cast_sbox6[U_INT8_Tc(x[0])] ^ cast_sbox7[U_INT8_Tb(x[0])] ^
175 cast_sbox8[U_INT8_Td(x[0])] ^ cast_sbox8[U_INT8_Tc(z[0])];
176 t[2] = x[2] = z[1] ^ cast_sbox5[U_INT8_Td(x[1])] ^
177 cast_sbox6[U_INT8_Tc(x[1])] ^ cast_sbox7[U_INT8_Tb(x[1])] ^
178 cast_sbox8[U_INT8_Ta(x[1])] ^ cast_sbox5[U_INT8_Tb(z[0])];
179 t[3] = x[3] = z[3] ^ cast_sbox5[U_INT8_Tc(x[2])] ^
180 cast_sbox6[U_INT8_Tb(x[2])] ^ cast_sbox7[U_INT8_Td(x[2])] ^
181 cast_sbox8[U_INT8_Ta(x[2])] ^ cast_sbox6[U_INT8_Td(z[0])];
182 break;
183 }
184 switch (i & 12) {
185 case 0:
186 case 12:
187 key->xkey[i+0] = cast_sbox5[U_INT8_Ta(t[2])] ^ cast_sbox6[U_INT8_Tb(t[2])] ^
188 cast_sbox7[U_INT8_Td(t[1])] ^ cast_sbox8[U_INT8_Tc(t[1])];
189 key->xkey[i+1] = cast_sbox5[U_INT8_Tc(t[2])] ^ cast_sbox6[U_INT8_Td(t[2])] ^
190 cast_sbox7[U_INT8_Tb(t[1])] ^ cast_sbox8[U_INT8_Ta(t[1])];
191 key->xkey[i+2] = cast_sbox5[U_INT8_Ta(t[3])] ^ cast_sbox6[U_INT8_Tb(t[3])] ^
192 cast_sbox7[U_INT8_Td(t[0])] ^ cast_sbox8[U_INT8_Tc(t[0])];
193 key->xkey[i+3] = cast_sbox5[U_INT8_Tc(t[3])] ^ cast_sbox6[U_INT8_Td(t[3])] ^
194 cast_sbox7[U_INT8_Tb(t[0])] ^ cast_sbox8[U_INT8_Ta(t[0])];
195 break;
196 case 4:
197 case 8:
198 key->xkey[i+0] = cast_sbox5[U_INT8_Td(t[0])] ^ cast_sbox6[U_INT8_Tc(t[0])] ^
199 cast_sbox7[U_INT8_Ta(t[3])] ^ cast_sbox8[U_INT8_Tb(t[3])];
200 key->xkey[i+1] = cast_sbox5[U_INT8_Tb(t[0])] ^ cast_sbox6[U_INT8_Ta(t[0])] ^
201 cast_sbox7[U_INT8_Tc(t[3])] ^ cast_sbox8[U_INT8_Td(t[3])];
202 key->xkey[i+2] = cast_sbox5[U_INT8_Td(t[1])] ^ cast_sbox6[U_INT8_Tc(t[1])] ^
203 cast_sbox7[U_INT8_Ta(t[2])] ^ cast_sbox8[U_INT8_Tb(t[2])];
204 key->xkey[i+3] = cast_sbox5[U_INT8_Tb(t[1])] ^ cast_sbox6[U_INT8_Ta(t[1])] ^
205 cast_sbox7[U_INT8_Tc(t[2])] ^ cast_sbox8[U_INT8_Td(t[2])];
206 break;
207 }
208 switch (i & 12) {
209 case 0:
210 key->xkey[i+0] ^= cast_sbox5[U_INT8_Tc(z[0])];
211 key->xkey[i+1] ^= cast_sbox6[U_INT8_Tc(z[1])];
212 key->xkey[i+2] ^= cast_sbox7[U_INT8_Tb(z[2])];
213 key->xkey[i+3] ^= cast_sbox8[U_INT8_Ta(z[3])];
214 break;
215 case 4:
216 key->xkey[i+0] ^= cast_sbox5[U_INT8_Ta(x[2])];
217 key->xkey[i+1] ^= cast_sbox6[U_INT8_Tb(x[3])];
218 key->xkey[i+2] ^= cast_sbox7[U_INT8_Td(x[0])];
219 key->xkey[i+3] ^= cast_sbox8[U_INT8_Td(x[1])];
220 break;
221 case 8:
222 key->xkey[i+0] ^= cast_sbox5[U_INT8_Tb(z[2])];
223 key->xkey[i+1] ^= cast_sbox6[U_INT8_Ta(z[3])];
224 key->xkey[i+2] ^= cast_sbox7[U_INT8_Tc(z[0])];
225 key->xkey[i+3] ^= cast_sbox8[U_INT8_Tc(z[1])];
226 break;
227 case 12:
228 key->xkey[i+0] ^= cast_sbox5[U_INT8_Td(x[0])];
229 key->xkey[i+1] ^= cast_sbox6[U_INT8_Td(x[1])];
230 key->xkey[i+2] ^= cast_sbox7[U_INT8_Ta(x[2])];
231 key->xkey[i+3] ^= cast_sbox8[U_INT8_Tb(x[3])];
232 break;
233 }
234 if (i >= 16) {
235 key->xkey[i+0] &= 31;
236 key->xkey[i+1] &= 31;
237 key->xkey[i+2] &= 31;
238 key->xkey[i+3] &= 31;
239 }
240 }
241 /* Wipe clean */
242 for (i = 0; i < 4; i++) {
243 t[i] = x[i] = z[i] = 0;
244 }
245 }
246
247 /* Made in Canada */
Cache object: e92c7716995b982ef84aa084a0866d6e
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