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1 /* cast5.c */
2 /*
3     This file is part of the ARM-Crypto-Lib.
4     Copyright (C) 2006-2010  Daniel Otte (daniel.otte@rub.de)
5
6     This program is free software: you can redistribute it and/or modify
7     it under the terms of the GNU General Public License as published by
8     the Free Software Foundation, either version 3 of the License, or
9     (at your option) any later version.
10
11     This program is distributed in the hope that it will be useful,
12     but WITHOUT ANY WARRANTY; without even the implied warranty of
13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14     GNU General Public License for more details.
15
16     You should have received a copy of the GNU General Public License
17     along with this program.  If not, see <http://www.gnu.org/licenses/>.
18 */
19 /* 
20  * \file        cast5.c
21  * \author      Daniel Otte
22  * \email       daniel.otte@rub.de
23  * \date        2006-07-26
24  * \par License:
25  *  GPLv3 or later
26  * \brief Implementation of the CAST5 (aka CAST-128) cipher algorithm as described in RFC 2144
27  * 
28  */
29  
30  #include <stdint.h>
31  #include <string.h>
32  #include "cast5.h"
33  #include "config.h"
34  
35  #undef DEBUG
36  
37  #ifdef DEBUG
38   #include "cli.h"
39  #endif
40  
41 #include "cast5-sbox.h"
42
43
44  
45 #define S5(x) (s5[(x)])
46 #define S6(x) (s6[(x)])
47 #define S7(x) (s7[(x)])
48 #define S8(x) (s8[(x)])
49
50 static 
51 void cast5_init_A(uint8_t *dest, uint8_t *src, bool bmode){
52         uint8_t mask = bmode?0x8:0;
53         *((uint32_t*)(&dest[0x0])) = *((uint32_t*)(&src[0x0^mask]))
54                                      ^ S5(src[0xD^mask]) ^ S6(src[0xF^mask]) 
55                                      ^ S7(src[0xC^mask]) ^ S8(src[0xE^mask]) 
56                                      ^ S7(src[0x8^mask]);
57         *((uint32_t*)(&dest[0x4])) = *((uint32_t*)(&src[0x8^mask])) 
58                                      ^ S5(dest[0x0]) ^ S6(dest[0x2]) 
59                                      ^ S7(dest[0x1]) ^ S8(dest[0x3]) 
60                                      ^ S8(src[0xA^mask]);
61         *((uint32_t*)(&dest[0x8])) = *((uint32_t*)(&src[0xC^mask])) 
62                                      ^ S5(dest[0x7]) ^ S6(dest[0x6]) 
63                                      ^ S7(dest[0x5]) ^ S8(dest[0x4]) 
64                                      ^ S5(src[0x9^mask]);
65         *((uint32_t*)(&dest[0xC])) = *((uint32_t*)(&src[0x4^mask])) 
66                                      ^ S5(dest[0xA]) 
67                                      ^ S6(dest[0x9]) 
68                                      ^ S7(dest[0xB]) 
69                                      ^ S8(dest[0x8]) 
70                                      ^ S6(src[0xB^mask]);
71 }
72
73 static
74 void cast5_init_M(uint8_t *dest, uint8_t *src, bool nmode, bool xmode){
75         uint8_t nmt[] = {0xB, 0xA, 0x9, 0x8, 
76                          0xF, 0xE, 0xD, 0xC, 
77                          0x3, 0x2, 0x1, 0x0, 
78                          0x7, 0x6, 0x5, 0x4}; /* nmode table */
79         uint8_t xmt[4][4] = {{0x2, 0x6, 0x9, 0xC}, 
80                              {0x8, 0xD, 0x3, 0x7}, 
81                              {0x3, 0x7, 0x8, 0xD}, 
82                              {0x9, 0xC, 0x2, 0x6}};
83         #define NMT(x) (src[nmode?nmt[(x)]:(x)])
84         #define XMT(x) (src[xmt[(xmode<<1) + nmode][(x)]])
85         *((uint32_t*)(&dest[0x0])) = S5(NMT(0x8)) ^ S6(NMT(0x9)) ^ S7(NMT(0x7)) ^ S8(NMT(0x6)) ^ S5(XMT(0));
86         *((uint32_t*)(&dest[0x4])) = S5(NMT(0xA)) ^ S6(NMT(0xB)) ^ S7(NMT(0x5)) ^ S8(NMT(0x4)) ^ S6(XMT(1));
87         *((uint32_t*)(&dest[0x8])) = S5(NMT(0xC)) ^ S6(NMT(0xD)) ^ S7(NMT(0x3)) ^ S8(NMT(0x2)) ^ S7(XMT(2));
88         *((uint32_t*)(&dest[0xC])) = S5(NMT(0xE)) ^ S6(NMT(0xF)) ^ S7(NMT(0x1)) ^ S8(NMT(0x0)) ^ S8(XMT(3));
89 }
90
91 #define S5B(x) *(3+(uint8_t*)(&s5[(x)]))
92 #define S6B(x) *(3+(uint8_t*)(&s6[(x)]))
93 #define S7B(x) *(3+(uint8_t*)(&s7[(x)]))
94 #define S8B(x) *(3+(uint8_t*)(&s8[(x)]))
95
96 static
97 void cast5_init_rM(uint8_t *klo, uint8_t *khi, uint8_t offset, uint8_t *src, bool nmode, bool xmode){
98         uint8_t nmt[] = {0xB, 0xA, 0x9, 0x8, 0xF, 0xE, 0xD, 0xC, 0x3, 0x2, 0x1, 0x0, 0x7, 0x6, 0x5, 0x4}; /* nmode table */
99         uint8_t xmt[4][4] = {{0x2, 0x6, 0x9, 0xC}, {0x8, 0xD, 0x3, 0x7}, {0x3, 0x7, 0x8, 0xD}, {0x9, 0xC, 0x2, 0x6}};
100         uint8_t t, h=0; 
101         t = S5B(NMT(0x8)) ^ S6B(NMT(0x9)) ^ S7B(NMT(0x7)) ^ S8B(NMT(0x6)) ^ S5B(XMT(0));
102                 klo[offset*2] |= (t & 0x0f);
103                 h |= (t&0x10); h>>=1;
104         t = S5B(NMT(0xA)) ^ S6B(NMT(0xB)) ^ S7B(NMT(0x5)) ^ S8B(NMT(0x4)) ^ S6B(XMT(1));
105                 klo[offset*2] |= (t<<4) & 0xf0;
106                 h |= t&0x10; h>>=1;
107         t = S5B(NMT(0xC)) ^ S6B(NMT(0xD)) ^ S7B(NMT(0x3)) ^ S8B(NMT(0x2)) ^ S7B(XMT(2));
108                 klo[offset*2+1] |= t&0xf;
109                 h |= t&0x10; h>>=1;
110         t = S5B(NMT(0xE)) ^ S6B(NMT(0xF)) ^ S7B(NMT(0x1)) ^ S8B(NMT(0x0)) ^ S8B(XMT(3));
111                 klo[offset*2+1] |= t<<4;
112                 h |= t&0x10; h >>=1;
113         #ifdef DEBUG
114                 cli_putstr("\r\n\t h="); cli_hexdump(&h,1);
115         #endif
116         khi[offset>>1] |= h<<((offset&0x1)?4:0);
117 }
118
119 #define S_5X(s) (s5[BPX[(s)]])
120 #define S_6X(s) (s6[BPX[(s)]])
121 #define S_7X(s) (s7[BPX[(s)]])
122 #define S_8X(s) (s8[BPX[(s)]])
123
124 #define S_5Z(s) (s5[BPZ[(s)]])
125 #define S_6Z(s) (s6[BPZ[(s)]])
126 #define S_7Z(s) (s7[BPZ[(s)]])
127 #define S_8Z(s) (s8[BPZ[(s)]])
128
129
130
131
132 void cast5_init(const void* key, uint16_t keylength_b, cast5_ctx_t* s){
133          /* we migth return if the key is valid and if setup was successful */
134         uint32_t x[4], z[4];
135         #define BPX ((uint8_t*)&(x[0]))
136         #define BPZ ((uint8_t*)&(z[0]))
137         s->shortkey = (keylength_b<=80);
138         /* littel endian only! */
139         memset(&(x[0]), 0 ,16); /* set x to zero */
140         if(keylength_b > 128)
141                 keylength_b=128;
142         memcpy(&(x[0]), key, (keylength_b+7)/8);
143         
144
145         /* todo: merge a and b and compress the whole stuff */
146         /***** A *****/
147         cast5_init_A((uint8_t*)(&z[0]), (uint8_t*)(&x[0]), false);      
148         /***** M *****/
149         cast5_init_M((uint8_t*)(&(s->mask[0])), (uint8_t*)(&z[0]), false, false);
150         /***** B *****/
151         cast5_init_A((uint8_t*)(&x[0]), (uint8_t*)(&z[0]), true);
152         /***** N *****/
153         cast5_init_M((uint8_t*)(&(s->mask[4])), (uint8_t*)(&x[0]), true, false);
154         /***** A *****/
155         cast5_init_A((uint8_t*)(&z[0]), (uint8_t*)(&x[0]), false);
156         /***** N' *****/
157         cast5_init_M((uint8_t*)(&(s->mask[8])), (uint8_t*)(&z[0]), true, true);
158         /***** B *****/
159         cast5_init_A((uint8_t*)(&x[0]), (uint8_t*)(&z[0]), true);
160         /***** M' *****/
161         cast5_init_M((uint8_t*)(&(s->mask[12])), (uint8_t*)(&x[0]), false, true);
162         
163         /* that were the masking keys, now the rotation keys */
164         /* set the keys to zero */
165         memset(&(s->rotl[0]),0,8);
166         s->roth[0]=s->roth[1]=0;
167         /***** A *****/
168         cast5_init_A((uint8_t*)(&z[0]), (uint8_t*)(&x[0]), false);
169         /***** M *****/
170         cast5_init_rM(&(s->rotl[0]), &(s->roth[0]), 0, (uint8_t*)(&z[0]), false, false);
171         /***** B *****/
172         cast5_init_A((uint8_t*)(&x[0]), (uint8_t*)(&z[0]), true);
173         /***** N *****/
174         cast5_init_rM(&(s->rotl[0]), &(s->roth[0]), 1, (uint8_t*)(&x[0]), true, false);
175         /***** A *****/
176         cast5_init_A((uint8_t*)(&z[0]), (uint8_t*)(&x[0]), false);
177         /***** N' *****/
178         cast5_init_rM(&(s->rotl[0]), &(s->roth[0]), 2, (uint8_t*)(&z[0]), true, true);
179         /***** B *****/
180         cast5_init_A((uint8_t*)(&x[0]), (uint8_t*)(&z[0]), true);
181         /***** M' *****/
182         cast5_init_rM(&(s->rotl[0]), &(s->roth[0]), 3, (uint8_t*)(&x[0]), false, true);
183         /* done ;-) */
184 }
185
186
187
188 /********************************************************************************************************/
189
190 #define ROTL32(a,n) ((a)<<(n) | (a)>>(32-(n)))
191 #define CHANGE_ENDIAN32(x) ((x)<<24 | (x)>>24 | ((x)&0xff00)<<8 | ((x)&0xff0000)>>8 )
192
193 typedef uint32_t cast5_f_t(uint32_t,uint32_t,uint8_t);
194
195 #define IA 3
196 #define IB 2
197 #define IC 1
198 #define ID 0
199
200 static
201 uint32_t cast5_f1(uint32_t d, uint32_t m, uint8_t r){
202         uint32_t t;
203         t = ROTL32((d + m),r);
204 #ifdef DEBUG
205         uint32_t ia,ib,ic,id;
206         cli_putstr("\r\n f1("); cli_hexdump(&d, 4); cli_putc(',');
207                 cli_hexdump(&m , 4); cli_putc(','); cli_hexdump(&r, 1);cli_putstr("): I=");
208                 cli_hexdump(&t, 4);
209         ia = s1[((uint8_t*)&t)[IA]];
210         ib = s2[((uint8_t*)&t)[IB]];
211         ic = s3[((uint8_t*)&t)[IC]];
212         id = s4[((uint8_t*)&t)[ID]];
213         cli_putstr("\r\n\tIA="); cli_hexdump(&ia, 4);
214         cli_putstr("\r\n\tIB="); cli_hexdump(&ib, 4);
215         cli_putstr("\r\n\tIC="); cli_hexdump(&ic, 4);
216         cli_putstr("\r\n\tID="); cli_hexdump(&id, 4);
217
218         return (((ia ^ ib) - ic) + id);
219
220 #else
221         
222         return (((  s1[((uint8_t*)&t)[IA]]
223               ^ s2[((uint8_t*)&t)[IB]] )
224                       - s3[((uint8_t*)&t)[IC]] )
225               + s4[((uint8_t*)&t)[ID]] );
226
227 #endif
228 }
229
230 static
231 uint32_t cast5_f2(uint32_t d, uint32_t m, uint8_t r){
232         uint32_t t;
233         t = ROTL32((d ^ m),r);
234 #ifdef DEBUG
235         uint32_t ia,ib,ic,id;
236         cli_putstr("\r\n f2("); cli_hexdump(&d, 4); cli_putc(',');
237                 cli_hexdump(&m , 4); cli_putc(','); cli_hexdump(&r, 1);cli_putstr("): I=");
238                 cli_hexdump(&t, 4);
239
240         ia = s1[((uint8_t*)&t)[IA]];
241         ib = s2[((uint8_t*)&t)[IB]];
242         ic = s3[((uint8_t*)&t)[IC]];
243         id = s4[((uint8_t*)&t)[ID]];
244         
245         cli_putstr("\r\n\tIA="); cli_hexdump(&ia, 4);
246         cli_putstr("\r\n\tIB="); cli_hexdump(&ib, 4);
247         cli_putstr("\r\n\tIC="); cli_hexdump(&ic, 4);
248         cli_putstr("\r\n\tID="); cli_hexdump(&id, 4);
249
250         return (((ia - ib) + ic) ^ id);
251 #else
252         
253         return ((( s1[((uint8_t*)&t)[IA]]
254                  - s2[((uint8_t*)&t)[IB]] )
255                      + s3[((uint8_t*)&t)[IC]] )
256                      ^ s4[((uint8_t*)&t)[ID]] );
257
258 #endif
259 }
260
261 static
262 uint32_t cast5_f3(uint32_t d, uint32_t m, uint8_t r){
263         uint32_t t;
264         t = ROTL32((m - d),r);
265
266 #ifdef DEBUG
267         uint32_t ia,ib,ic,id;
268
269         cli_putstr("\r\n f3("); cli_hexdump(&d, 4); cli_putc(',');
270                 cli_hexdump(&m , 4); cli_putc(','); cli_hexdump(&r, 1);cli_putstr("): I=");
271                 cli_hexdump(&t, 4);
272
273         ia = s1[((uint8_t*)&t)[IA]];
274         ib = s2[((uint8_t*)&t)[IB]];
275         ic = s3[((uint8_t*)&t)[IC]];
276         id = s4[((uint8_t*)&t)[ID]];
277         
278         cli_putstr("\r\n\tIA="); cli_hexdump(&ia, 4);
279         cli_putstr("\r\n\tIB="); cli_hexdump(&ib, 4);
280         cli_putstr("\r\n\tIC="); cli_hexdump(&ic, 4);
281         cli_putstr("\r\n\tID="); cli_hexdump(&id, 4);
282         return (((ia + ib) ^ ic) - id);
283 #else
284         return ((  s1[((uint8_t*)&t)[IA]]
285              + s2[((uint8_t*)&t)[IB]])
286                      ^ s3[((uint8_t*)&t)[IC]])
287              - s4[((uint8_t*)&t)[ID]];
288
289 #endif
290 }
291
292 /******************************************************************************/
293
294 void cast5_enc(void* block, const cast5_ctx_t *s){
295         uint32_t l,r, x, y;
296         uint8_t i;
297         cast5_f_t* f[]={cast5_f1,cast5_f2,cast5_f3};
298         l=((uint32_t*)block)[0];
299         r=((uint32_t*)block)[1];
300 //      cli_putstr("\r\n round[-1] = ");
301 //      cli_hexdump(&r, 4);
302         for (i=0;i<(s->shortkey?12:16);++i){
303                 x = r;
304                 y = (f[i%3])(CHANGE_ENDIAN32(r), CHANGE_ENDIAN32(s->mask[i]), 
305                         (((s->roth[i>>3]) & (1<<(i&0x7)))?0x10:0x00) 
306                          + ( ((s->rotl[i>>1])>>((i&1)?4:0)) & 0x0f) );
307                 r = l ^ CHANGE_ENDIAN32(y);
308 //              cli_putstr("\r\n round["); DEBUG_B(i); cli_putstr("] = ");
309 //              cli_hexdump(&r, 4);
310                 l = x;
311         }
312         ((uint32_t*)block)[0]=r;
313         ((uint32_t*)block)[1]=l;
314 }
315
316 /******************************************************************************/
317
318 void cast5_dec(void* block, const cast5_ctx_t *s){
319         uint32_t l,r, x, y;
320         int8_t i, rounds;
321         cast5_f_t* f[]={cast5_f1,cast5_f2,cast5_f3};
322         l=((uint32_t*)block)[0];
323         r=((uint32_t*)block)[1];
324         rounds = (s->shortkey?12:16);
325         for (i=rounds-1; i>=0 ;--i){
326                 x = r;
327                 y = (f[i%3])(CHANGE_ENDIAN32(r), CHANGE_ENDIAN32(s->mask[i]), 
328                         (((s->roth[i>>3]) & (1<<(i&0x7)))?0x10:0x00) 
329                          + ( ((s->rotl[i>>1])>>((i&1)?4:0)) & 0x0f) );
330                 r = l ^ CHANGE_ENDIAN32(y);
331                 l = x;
332         }
333         ((uint32_t*)block)[0]=r;
334         ((uint32_t*)block)[1]=l;
335 }
336
337
338 /******************************************************************************/
339
340
341
342