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 $ */
3 /*-
4 * CAST-128 in C
5 * Written by Steve Reid <sreid@sea-to-sky.net>
6 * 100% Public Domain - no warranty
7 * Released 1997.10.11
8 */
9
10 #include <sys/types.h>
11 #include <opencrypto/cast.h>
12 #include <opencrypto/castsb.h>
13
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) )
19
20 /* Circular left shift */
21 #define ROL(x, n) ( ((x)<<(n)) | ((x)>>(32-(n))) )
22
23 /* CAST-128 uses three different round functions */
24 #define F1(l, r, i) \
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)];
28 #define F2(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 F3(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
37
38 /***** Encryption Function *****/
39
cast_encrypt(cast_key * key,u_int8_t * inblock,u_int8_t * outblock)40 void cast_encrypt(cast_key* key, u_int8_t* inblock, u_int8_t* outblock)
41 {
42 u_int32_t t, l, r;
43
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];
49 /* Do the work */
50 F1(l, r, 0);
51 F2(r, l, 1);
52 F3(l, r, 2);
53 F1(r, l, 3);
54 F2(l, r, 4);
55 F3(r, l, 5);
56 F1(l, r, 6);
57 F2(r, l, 7);
58 F3(l, r, 8);
59 F1(r, l, 9);
60 F2(l, r, 10);
61 F3(r, l, 11);
62 /* Only do full 16 rounds if key length > 80 bits */
63 if (key->rounds > 12) {
64 F1(l, r, 12);
65 F2(r, l, 13);
66 F3(l, r, 14);
67 F1(r, l, 15);
68 }
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);
78 /* Wipe clean */
79 t = l = r = 0;
80 }
81
82
83 /***** Decryption Function *****/
84
cast_decrypt(cast_key * key,u_int8_t * inblock,u_int8_t * outblock)85 void cast_decrypt(cast_key* key, u_int8_t* inblock, u_int8_t* outblock)
86 {
87 u_int32_t t, l, r;
88
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];
94 /* Do the work */
95 /* Only do full 16 rounds if key length > 80 bits */
96 if (key->rounds > 12) {
97 F1(r, l, 15);
98 F3(l, r, 14);
99 F2(r, l, 13);
100 F1(l, r, 12);
101 }
102 F3(r, l, 11);
103 F2(l, r, 10);
104 F1(r, l, 9);
105 F3(l, r, 8);
106 F2(r, l, 7);
107 F1(l, r, 6);
108 F3(r, l, 5);
109 F2(l, r, 4);
110 F1(r, l, 3);
111 F3(l, r, 2);
112 F2(r, l, 1);
113 F1(l, r, 0);
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);
123 /* Wipe clean */
124 t = l = r = 0;
125 }
126
127
128 /***** Key Schedual *****/
129
cast_setkey(cast_key * key,u_int8_t * rawkey,int keybytes)130 void cast_setkey(cast_key* key, u_int8_t* rawkey, int keybytes)
131 {
132 u_int32_t t[4] = {0, 0, 0, 0}, z[4] = {0, 0, 0, 0}, x[4];
133 int i;
134
135 /* Set number of rounds to 12 or 16, depending on key length */
136 key->rounds = (keybytes <= 10 ? 12 : 16);
137
138 /* Copy key to workspace x */
139 for (i = 0; i < 4; i++) {
140 x[i] = 0;
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];
145 }
146 /* Generate 32 subkeys, four at a time */
147 for (i = 0; i < 32; i+=4) {
148 switch (i & 4) {
149 case 0:
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])];
162 break;
163 case 4:
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])];
176 break;
177 }
178 switch (i & 12) {
179 case 0:
180 case 12:
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])];
189 break;
190 case 4:
191 case 8:
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])];
200 break;
201 }
202 switch (i & 12) {
203 case 0:
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])];
208 break;
209 case 4:
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])];
214 break;
215 case 8:
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])];
220 break;
221 case 12:
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])];
226 break;
227 }
228 if (i >= 16) {
229 key->xkey[i+0] &= 31;
230 key->xkey[i+1] &= 31;
231 key->xkey[i+2] &= 31;
232 key->xkey[i+3] &= 31;
233 }
234 }
235 /* Wipe clean */
236 for (i = 0; i < 4; i++) {
237 t[i] = x[i] = z[i] = 0;
238 }
239 }
240
241 /* Made in Canada */
242
243