FreeBSD/Linux Kernel Cross Reference
sys/opencrypto/cast.c
1 /* $FreeBSD$ */
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/types.h>
12 #include <opencrypto/cast.h>
13 #include <opencrypto/castsb.h>
14
15 /* Macros to access 8-bit bytes out of a 32-bit word */
16 #define U_INT8_Ta(x) ( (u_int8_t) (x>>24) )
17 #define U_INT8_Tb(x) ( (u_int8_t) ((x>>16)&255) )
18 #define U_INT8_Tc(x) ( (u_int8_t) ((x>>8)&255) )
19 #define U_INT8_Td(x) ( (u_int8_t) ((x)&255) )
20
21 /* Circular left shift */
22 #define ROL(x, n) ( ((x)<<(n)) | ((x)>>(32-(n))) )
23
24 /* CAST-128 uses three different round functions */
25 #define F1(l, r, i) \
26 t = ROL(key->xkey[i] + r, key->xkey[i+16]); \
27 l ^= ((cast_sbox1[U_INT8_Ta(t)] ^ cast_sbox2[U_INT8_Tb(t)]) - \
28 cast_sbox3[U_INT8_Tc(t)]) + cast_sbox4[U_INT8_Td(t)];
29 #define F2(l, r, i) \
30 t = ROL(key->xkey[i] ^ r, key->xkey[i+16]); \
31 l ^= ((cast_sbox1[U_INT8_Ta(t)] - cast_sbox2[U_INT8_Tb(t)]) + \
32 cast_sbox3[U_INT8_Tc(t)]) ^ cast_sbox4[U_INT8_Td(t)];
33 #define F3(l, r, i) \
34 t = ROL(key->xkey[i] - r, key->xkey[i+16]); \
35 l ^= ((cast_sbox1[U_INT8_Ta(t)] + cast_sbox2[U_INT8_Tb(t)]) ^ \
36 cast_sbox3[U_INT8_Tc(t)]) - cast_sbox4[U_INT8_Td(t)];
37
38
39 /***** Encryption Function *****/
40
41 void cast_encrypt(cast_key* key, u_int8_t* inblock, u_int8_t* outblock)
42 {
43 u_int32_t t, l, r;
44
45 /* Get inblock into l,r */
46 l = ((u_int32_t)inblock[0] << 24) | ((u_int32_t)inblock[1] << 16) |
47 ((u_int32_t)inblock[2] << 8) | (u_int32_t)inblock[3];
48 r = ((u_int32_t)inblock[4] << 24) | ((u_int32_t)inblock[5] << 16) |
49 ((u_int32_t)inblock[6] << 8) | (u_int32_t)inblock[7];
50 /* Do the work */
51 F1(l, r, 0);
52 F2(r, l, 1);
53 F3(l, r, 2);
54 F1(r, l, 3);
55 F2(l, r, 4);
56 F3(r, l, 5);
57 F1(l, r, 6);
58 F2(r, l, 7);
59 F3(l, r, 8);
60 F1(r, l, 9);
61 F2(l, r, 10);
62 F3(r, l, 11);
63 /* Only do full 16 rounds if key length > 80 bits */
64 if (key->rounds > 12) {
65 F1(l, r, 12);
66 F2(r, l, 13);
67 F3(l, r, 14);
68 F1(r, l, 15);
69 }
70 /* Put l,r into outblock */
71 outblock[0] = U_INT8_Ta(r);
72 outblock[1] = U_INT8_Tb(r);
73 outblock[2] = U_INT8_Tc(r);
74 outblock[3] = U_INT8_Td(r);
75 outblock[4] = U_INT8_Ta(l);
76 outblock[5] = U_INT8_Tb(l);
77 outblock[6] = U_INT8_Tc(l);
78 outblock[7] = U_INT8_Td(l);
79 /* Wipe clean */
80 t = l = r = 0;
81 }
82
83
84 /***** Decryption Function *****/
85
86 void cast_decrypt(cast_key* key, u_int8_t* inblock, u_int8_t* outblock)
87 {
88 u_int32_t t, l, r;
89
90 /* Get inblock into l,r */
91 r = ((u_int32_t)inblock[0] << 24) | ((u_int32_t)inblock[1] << 16) |
92 ((u_int32_t)inblock[2] << 8) | (u_int32_t)inblock[3];
93 l = ((u_int32_t)inblock[4] << 24) | ((u_int32_t)inblock[5] << 16) |
94 ((u_int32_t)inblock[6] << 8) | (u_int32_t)inblock[7];
95 /* Do the work */
96 /* Only do full 16 rounds if key length > 80 bits */
97 if (key->rounds > 12) {
98 F1(r, l, 15);
99 F3(l, r, 14);
100 F2(r, l, 13);
101 F1(l, r, 12);
102 }
103 F3(r, l, 11);
104 F2(l, r, 10);
105 F1(r, l, 9);
106 F3(l, r, 8);
107 F2(r, l, 7);
108 F1(l, r, 6);
109 F3(r, l, 5);
110 F2(l, r, 4);
111 F1(r, l, 3);
112 F3(l, r, 2);
113 F2(r, l, 1);
114 F1(l, r, 0);
115 /* Put l,r into outblock */
116 outblock[0] = U_INT8_Ta(l);
117 outblock[1] = U_INT8_Tb(l);
118 outblock[2] = U_INT8_Tc(l);
119 outblock[3] = U_INT8_Td(l);
120 outblock[4] = U_INT8_Ta(r);
121 outblock[5] = U_INT8_Tb(r);
122 outblock[6] = U_INT8_Tc(r);
123 outblock[7] = U_INT8_Td(r);
124 /* Wipe clean */
125 t = l = r = 0;
126 }
127
128
129 /***** Key Schedual *****/
130
131 void cast_setkey(cast_key* key, u_int8_t* rawkey, int keybytes)
132 {
133 u_int32_t t[4], z[4], x[4];
134 int i;
135
136 /* Set number of rounds to 12 or 16, depending on key length */
137 key->rounds = (keybytes <= 10 ? 12 : 16);
138
139 /* Copy key to workspace x */
140 for (i = 0; i < 4; i++) {
141 x[i] = 0;
142 if ((i*4+0) < keybytes) x[i] = (u_int32_t)rawkey[i*4+0] << 24;
143 if ((i*4+1) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+1] << 16;
144 if ((i*4+2) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+2] << 8;
145 if ((i*4+3) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+3];
146 }
147 /* Generate 32 subkeys, four at a time */
148 for (i = 0; i < 32; i+=4) {
149 switch (i & 4) {
150 case 0:
151 t[0] = z[0] = x[0] ^ cast_sbox5[U_INT8_Tb(x[3])] ^
152 cast_sbox6[U_INT8_Td(x[3])] ^ cast_sbox7[U_INT8_Ta(x[3])] ^
153 cast_sbox8[U_INT8_Tc(x[3])] ^ cast_sbox7[U_INT8_Ta(x[2])];
154 t[1] = z[1] = x[2] ^ cast_sbox5[U_INT8_Ta(z[0])] ^
155 cast_sbox6[U_INT8_Tc(z[0])] ^ cast_sbox7[U_INT8_Tb(z[0])] ^
156 cast_sbox8[U_INT8_Td(z[0])] ^ cast_sbox8[U_INT8_Tc(x[2])];
157 t[2] = z[2] = x[3] ^ cast_sbox5[U_INT8_Td(z[1])] ^
158 cast_sbox6[U_INT8_Tc(z[1])] ^ cast_sbox7[U_INT8_Tb(z[1])] ^
159 cast_sbox8[U_INT8_Ta(z[1])] ^ cast_sbox5[U_INT8_Tb(x[2])];
160 t[3] = z[3] = x[1] ^ cast_sbox5[U_INT8_Tc(z[2])] ^
161 cast_sbox6[U_INT8_Tb(z[2])] ^ cast_sbox7[U_INT8_Td(z[2])] ^
162 cast_sbox8[U_INT8_Ta(z[2])] ^ cast_sbox6[U_INT8_Td(x[2])];
163 break;
164 case 4:
165 t[0] = x[0] = z[2] ^ cast_sbox5[U_INT8_Tb(z[1])] ^
166 cast_sbox6[U_INT8_Td(z[1])] ^ cast_sbox7[U_INT8_Ta(z[1])] ^
167 cast_sbox8[U_INT8_Tc(z[1])] ^ cast_sbox7[U_INT8_Ta(z[0])];
168 t[1] = x[1] = z[0] ^ cast_sbox5[U_INT8_Ta(x[0])] ^
169 cast_sbox6[U_INT8_Tc(x[0])] ^ cast_sbox7[U_INT8_Tb(x[0])] ^
170 cast_sbox8[U_INT8_Td(x[0])] ^ cast_sbox8[U_INT8_Tc(z[0])];
171 t[2] = x[2] = z[1] ^ cast_sbox5[U_INT8_Td(x[1])] ^
172 cast_sbox6[U_INT8_Tc(x[1])] ^ cast_sbox7[U_INT8_Tb(x[1])] ^
173 cast_sbox8[U_INT8_Ta(x[1])] ^ cast_sbox5[U_INT8_Tb(z[0])];
174 t[3] = x[3] = z[3] ^ cast_sbox5[U_INT8_Tc(x[2])] ^
175 cast_sbox6[U_INT8_Tb(x[2])] ^ cast_sbox7[U_INT8_Td(x[2])] ^
176 cast_sbox8[U_INT8_Ta(x[2])] ^ cast_sbox6[U_INT8_Td(z[0])];
177 break;
178 }
179 switch (i & 12) {
180 case 0:
181 case 12:
182 key->xkey[i+0] = cast_sbox5[U_INT8_Ta(t[2])] ^ cast_sbox6[U_INT8_Tb(t[2])] ^
183 cast_sbox7[U_INT8_Td(t[1])] ^ cast_sbox8[U_INT8_Tc(t[1])];
184 key->xkey[i+1] = cast_sbox5[U_INT8_Tc(t[2])] ^ cast_sbox6[U_INT8_Td(t[2])] ^
185 cast_sbox7[U_INT8_Tb(t[1])] ^ cast_sbox8[U_INT8_Ta(t[1])];
186 key->xkey[i+2] = cast_sbox5[U_INT8_Ta(t[3])] ^ cast_sbox6[U_INT8_Tb(t[3])] ^
187 cast_sbox7[U_INT8_Td(t[0])] ^ cast_sbox8[U_INT8_Tc(t[0])];
188 key->xkey[i+3] = cast_sbox5[U_INT8_Tc(t[3])] ^ cast_sbox6[U_INT8_Td(t[3])] ^
189 cast_sbox7[U_INT8_Tb(t[0])] ^ cast_sbox8[U_INT8_Ta(t[0])];
190 break;
191 case 4:
192 case 8:
193 key->xkey[i+0] = cast_sbox5[U_INT8_Td(t[0])] ^ cast_sbox6[U_INT8_Tc(t[0])] ^
194 cast_sbox7[U_INT8_Ta(t[3])] ^ cast_sbox8[U_INT8_Tb(t[3])];
195 key->xkey[i+1] = cast_sbox5[U_INT8_Tb(t[0])] ^ cast_sbox6[U_INT8_Ta(t[0])] ^
196 cast_sbox7[U_INT8_Tc(t[3])] ^ cast_sbox8[U_INT8_Td(t[3])];
197 key->xkey[i+2] = cast_sbox5[U_INT8_Td(t[1])] ^ cast_sbox6[U_INT8_Tc(t[1])] ^
198 cast_sbox7[U_INT8_Ta(t[2])] ^ cast_sbox8[U_INT8_Tb(t[2])];
199 key->xkey[i+3] = cast_sbox5[U_INT8_Tb(t[1])] ^ cast_sbox6[U_INT8_Ta(t[1])] ^
200 cast_sbox7[U_INT8_Tc(t[2])] ^ cast_sbox8[U_INT8_Td(t[2])];
201 break;
202 }
203 switch (i & 12) {
204 case 0:
205 key->xkey[i+0] ^= cast_sbox5[U_INT8_Tc(z[0])];
206 key->xkey[i+1] ^= cast_sbox6[U_INT8_Tc(z[1])];
207 key->xkey[i+2] ^= cast_sbox7[U_INT8_Tb(z[2])];
208 key->xkey[i+3] ^= cast_sbox8[U_INT8_Ta(z[3])];
209 break;
210 case 4:
211 key->xkey[i+0] ^= cast_sbox5[U_INT8_Ta(x[2])];
212 key->xkey[i+1] ^= cast_sbox6[U_INT8_Tb(x[3])];
213 key->xkey[i+2] ^= cast_sbox7[U_INT8_Td(x[0])];
214 key->xkey[i+3] ^= cast_sbox8[U_INT8_Td(x[1])];
215 break;
216 case 8:
217 key->xkey[i+0] ^= cast_sbox5[U_INT8_Tb(z[2])];
218 key->xkey[i+1] ^= cast_sbox6[U_INT8_Ta(z[3])];
219 key->xkey[i+2] ^= cast_sbox7[U_INT8_Tc(z[0])];
220 key->xkey[i+3] ^= cast_sbox8[U_INT8_Tc(z[1])];
221 break;
222 case 12:
223 key->xkey[i+0] ^= cast_sbox5[U_INT8_Td(x[0])];
224 key->xkey[i+1] ^= cast_sbox6[U_INT8_Td(x[1])];
225 key->xkey[i+2] ^= cast_sbox7[U_INT8_Ta(x[2])];
226 key->xkey[i+3] ^= cast_sbox8[U_INT8_Tb(x[3])];
227 break;
228 }
229 if (i >= 16) {
230 key->xkey[i+0] &= 31;
231 key->xkey[i+1] &= 31;
232 key->xkey[i+2] &= 31;
233 key->xkey[i+3] &= 31;
234 }
235 }
236 /* Wipe clean */
237 for (i = 0; i < 4; i++) {
238 t[i] = x[i] = z[i] = 0;
239 }
240 }
241
242 /* Made in Canada */
243
Cache object: 3f1da607d47544400b65f4f7cc0bdac4
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