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authorprovos <>1998-07-21 22:23:20 +0000
committerprovos <>1998-07-21 22:23:20 +0000
commitdbd466e2fd7a3d79f407cccbbe8cd826429790d8 (patch)
treecf1adc8c4ef8c3203083f3998c8bcca89cd45af9 /src/lib/libc/crypt/cast.c
parentb811c9ad609b90ad8a28b3d5e9044db773f24841 (diff)
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Add CAST encryption, implementation by Steve Reid <sreid@sea-to-sky.net>.
Man pages will come soon, I hope.
Diffstat (limited to '')
-rw-r--r--src/lib/libc/crypt/cast.c240
1 files changed, 240 insertions, 0 deletions
diff --git a/src/lib/libc/crypt/cast.c b/src/lib/libc/crypt/cast.c
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1/* $OpenBSD: cast.c,v 1.1 1998/07/21 22:23:19 provos Exp $ */
2/*
3 * CAST-128 in C
4 * Written by Steve Reid <sreid@sea-to-sky.net>
5 * 100% Public Domain - no warranty
6 * Released 1997.10.11
7 */
8
9#include <netinet/ip_cast.h>
10#include <netinet/ip_castsb.h>
11
12/* Macros to access 8-bit bytes out of a 32-bit word */
13#define U8a(x) ( (u8) (x>>24) )
14#define U8b(x) ( (u8) ((x>>16)&255) )
15#define U8c(x) ( (u8) ((x>>8)&255) )
16#define U8d(x) ( (u8) ((x)&255) )
17
18/* Circular left shift */
19#define ROL(x, n) ( ((x)<<(n)) | ((x)>>(32-(n))) )
20
21/* CAST-128 uses three different round functions */
22#define F1(l, r, i) \
23 t = ROL(key->xkey[i] + r, key->xkey[i+16]); \
24 l ^= ((cast_sbox1[U8a(t)] ^ cast_sbox2[U8b(t)]) - \
25 cast_sbox3[U8c(t)]) + cast_sbox4[U8d(t)];
26#define F2(l, r, i) \
27 t = ROL(key->xkey[i] ^ r, key->xkey[i+16]); \
28 l ^= ((cast_sbox1[U8a(t)] - cast_sbox2[U8b(t)]) + \
29 cast_sbox3[U8c(t)]) ^ cast_sbox4[U8d(t)];
30#define F3(l, r, i) \
31 t = ROL(key->xkey[i] - r, key->xkey[i+16]); \
32 l ^= ((cast_sbox1[U8a(t)] + cast_sbox2[U8b(t)]) ^ \
33 cast_sbox3[U8c(t)]) - cast_sbox4[U8d(t)];
34
35
36/***** Encryption Function *****/
37
38void cast_encrypt(cast_key* key, u8* inblock, u8* outblock)
39{
40u32 t, l, r;
41
42 /* Get inblock into l,r */
43 l = ((u32)inblock[0] << 24) | ((u32)inblock[1] << 16) |
44 ((u32)inblock[2] << 8) | (u32)inblock[3];
45 r = ((u32)inblock[4] << 24) | ((u32)inblock[5] << 16) |
46 ((u32)inblock[6] << 8) | (u32)inblock[7];
47 /* Do the work */
48 F1(l, r, 0);
49 F2(r, l, 1);
50 F3(l, r, 2);
51 F1(r, l, 3);
52 F2(l, r, 4);
53 F3(r, l, 5);
54 F1(l, r, 6);
55 F2(r, l, 7);
56 F3(l, r, 8);
57 F1(r, l, 9);
58 F2(l, r, 10);
59 F3(r, l, 11);
60 /* Only do full 16 rounds if key length > 80 bits */
61 if (key->rounds > 12) {
62 F1(l, r, 12);
63 F2(r, l, 13);
64 F3(l, r, 14);
65 F1(r, l, 15);
66 }
67 /* Put l,r into outblock */
68 outblock[0] = U8a(r);
69 outblock[1] = U8b(r);
70 outblock[2] = U8c(r);
71 outblock[3] = U8d(r);
72 outblock[4] = U8a(l);
73 outblock[5] = U8b(l);
74 outblock[6] = U8c(l);
75 outblock[7] = U8d(l);
76 /* Wipe clean */
77 t = l = r = 0;
78}
79
80
81/***** Decryption Function *****/
82
83void cast_decrypt(cast_key* key, u8* inblock, u8* outblock)
84{
85u32 t, l, r;
86
87 /* Get inblock into l,r */
88 r = ((u32)inblock[0] << 24) | ((u32)inblock[1] << 16) |
89 ((u32)inblock[2] << 8) | (u32)inblock[3];
90 l = ((u32)inblock[4] << 24) | ((u32)inblock[5] << 16) |
91 ((u32)inblock[6] << 8) | (u32)inblock[7];
92 /* Do the work */
93 /* Only do full 16 rounds if key length > 80 bits */
94 if (key->rounds > 12) {
95 F1(r, l, 15);
96 F3(l, r, 14);
97 F2(r, l, 13);
98 F1(l, r, 12);
99 }
100 F3(r, l, 11);
101 F2(l, r, 10);
102 F1(r, l, 9);
103 F3(l, r, 8);
104 F2(r, l, 7);
105 F1(l, r, 6);
106 F3(r, l, 5);
107 F2(l, r, 4);
108 F1(r, l, 3);
109 F3(l, r, 2);
110 F2(r, l, 1);
111 F1(l, r, 0);
112 /* Put l,r into outblock */
113 outblock[0] = U8a(l);
114 outblock[1] = U8b(l);
115 outblock[2] = U8c(l);
116 outblock[3] = U8d(l);
117 outblock[4] = U8a(r);
118 outblock[5] = U8b(r);
119 outblock[6] = U8c(r);
120 outblock[7] = U8d(r);
121 /* Wipe clean */
122 t = l = r = 0;
123}
124
125
126/***** Key Schedual *****/
127
128void cast_setkey(cast_key* key, u8* rawkey, int keybytes)
129{
130u32 t[4], z[4], x[4];
131int i;
132
133 /* Set number of rounds to 12 or 16, depending on key length */
134 key->rounds = (keybytes <= 10 ? 12 : 16);
135
136 /* Copy key to workspace x */
137 for (i = 0; i < 4; i++) {
138 x[i] = 0;
139 if ((i*4+0) < keybytes) x[i] = (u32)rawkey[i*4+0] << 24;
140 if ((i*4+1) < keybytes) x[i] |= (u32)rawkey[i*4+1] << 16;
141 if ((i*4+2) < keybytes) x[i] |= (u32)rawkey[i*4+2] << 8;
142 if ((i*4+3) < keybytes) x[i] |= (u32)rawkey[i*4+3];
143 }
144 /* Generate 32 subkeys, four at a time */
145 for (i = 0; i < 32; i+=4) {
146 switch (i & 4) {
147 case 0:
148 t[0] = z[0] = x[0] ^ cast_sbox5[U8b(x[3])] ^
149 cast_sbox6[U8d(x[3])] ^ cast_sbox7[U8a(x[3])] ^
150 cast_sbox8[U8c(x[3])] ^ cast_sbox7[U8a(x[2])];
151 t[1] = z[1] = x[2] ^ cast_sbox5[U8a(z[0])] ^
152 cast_sbox6[U8c(z[0])] ^ cast_sbox7[U8b(z[0])] ^
153 cast_sbox8[U8d(z[0])] ^ cast_sbox8[U8c(x[2])];
154 t[2] = z[2] = x[3] ^ cast_sbox5[U8d(z[1])] ^
155 cast_sbox6[U8c(z[1])] ^ cast_sbox7[U8b(z[1])] ^
156 cast_sbox8[U8a(z[1])] ^ cast_sbox5[U8b(x[2])];
157 t[3] = z[3] = x[1] ^ cast_sbox5[U8c(z[2])] ^
158 cast_sbox6[U8b(z[2])] ^ cast_sbox7[U8d(z[2])] ^
159 cast_sbox8[U8a(z[2])] ^ cast_sbox6[U8d(x[2])];
160 break;
161 case 4:
162 t[0] = x[0] = z[2] ^ cast_sbox5[U8b(z[1])] ^
163 cast_sbox6[U8d(z[1])] ^ cast_sbox7[U8a(z[1])] ^
164 cast_sbox8[U8c(z[1])] ^ cast_sbox7[U8a(z[0])];
165 t[1] = x[1] = z[0] ^ cast_sbox5[U8a(x[0])] ^
166 cast_sbox6[U8c(x[0])] ^ cast_sbox7[U8b(x[0])] ^
167 cast_sbox8[U8d(x[0])] ^ cast_sbox8[U8c(z[0])];
168 t[2] = x[2] = z[1] ^ cast_sbox5[U8d(x[1])] ^
169 cast_sbox6[U8c(x[1])] ^ cast_sbox7[U8b(x[1])] ^
170 cast_sbox8[U8a(x[1])] ^ cast_sbox5[U8b(z[0])];
171 t[3] = x[3] = z[3] ^ cast_sbox5[U8c(x[2])] ^
172 cast_sbox6[U8b(x[2])] ^ cast_sbox7[U8d(x[2])] ^
173 cast_sbox8[U8a(x[2])] ^ cast_sbox6[U8d(z[0])];
174 break;
175 }
176 switch (i & 12) {
177 case 0:
178 case 12:
179 key->xkey[i+0] = cast_sbox5[U8a(t[2])] ^ cast_sbox6[U8b(t[2])] ^
180 cast_sbox7[U8d(t[1])] ^ cast_sbox8[U8c(t[1])];
181 key->xkey[i+1] = cast_sbox5[U8c(t[2])] ^ cast_sbox6[U8d(t[2])] ^
182 cast_sbox7[U8b(t[1])] ^ cast_sbox8[U8a(t[1])];
183 key->xkey[i+2] = cast_sbox5[U8a(t[3])] ^ cast_sbox6[U8b(t[3])] ^
184 cast_sbox7[U8d(t[0])] ^ cast_sbox8[U8c(t[0])];
185 key->xkey[i+3] = cast_sbox5[U8c(t[3])] ^ cast_sbox6[U8d(t[3])] ^
186 cast_sbox7[U8b(t[0])] ^ cast_sbox8[U8a(t[0])];
187 break;
188 case 4:
189 case 8:
190 key->xkey[i+0] = cast_sbox5[U8d(t[0])] ^ cast_sbox6[U8c(t[0])] ^
191 cast_sbox7[U8a(t[3])] ^ cast_sbox8[U8b(t[3])];
192 key->xkey[i+1] = cast_sbox5[U8b(t[0])] ^ cast_sbox6[U8a(t[0])] ^
193 cast_sbox7[U8c(t[3])] ^ cast_sbox8[U8d(t[3])];
194 key->xkey[i+2] = cast_sbox5[U8d(t[1])] ^ cast_sbox6[U8c(t[1])] ^
195 cast_sbox7[U8a(t[2])] ^ cast_sbox8[U8b(t[2])];
196 key->xkey[i+3] = cast_sbox5[U8b(t[1])] ^ cast_sbox6[U8a(t[1])] ^
197 cast_sbox7[U8c(t[2])] ^ cast_sbox8[U8d(t[2])];
198 break;
199 }
200 switch (i & 12) {
201 case 0:
202 key->xkey[i+0] ^= cast_sbox5[U8c(z[0])];
203 key->xkey[i+1] ^= cast_sbox6[U8c(z[1])];
204 key->xkey[i+2] ^= cast_sbox7[U8b(z[2])];
205 key->xkey[i+3] ^= cast_sbox8[U8a(z[3])];
206 break;
207 case 4:
208 key->xkey[i+0] ^= cast_sbox5[U8a(x[2])];
209 key->xkey[i+1] ^= cast_sbox6[U8b(x[3])];
210 key->xkey[i+2] ^= cast_sbox7[U8d(x[0])];
211 key->xkey[i+3] ^= cast_sbox8[U8d(x[1])];
212 break;
213 case 8:
214 key->xkey[i+0] ^= cast_sbox5[U8b(z[2])];
215 key->xkey[i+1] ^= cast_sbox6[U8a(z[3])];
216 key->xkey[i+2] ^= cast_sbox7[U8c(z[0])];
217 key->xkey[i+3] ^= cast_sbox8[U8c(z[1])];
218 break;
219 case 12:
220 key->xkey[i+0] ^= cast_sbox5[U8d(x[0])];
221 key->xkey[i+1] ^= cast_sbox6[U8d(x[1])];
222 key->xkey[i+2] ^= cast_sbox7[U8a(x[2])];
223 key->xkey[i+3] ^= cast_sbox8[U8b(x[3])];
224 break;
225 }
226 if (i >= 16) {
227 key->xkey[i+0] &= 31;
228 key->xkey[i+1] &= 31;
229 key->xkey[i+2] &= 31;
230 key->xkey[i+3] &= 31;
231 }
232 }
233 /* Wipe clean */
234 for (i = 0; i < 4; i++) {
235 t[i] = x[i] = z[i] = 0;
236 }
237}
238
239/* Made in Canada */
240
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