cast5.c

   1 /* cast5.c */
   2 /*
   3     This file is part of the AVR-Crypto-Lib.
   4     Copyright (C) 2008  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  #include "debug.h"
  35
  36  #undef DEBUG
  37
  38  #ifdef DEBUG
  39   #include "uart.h"
  40  #endif
  41
  42 #include "cast5-sbox.h"
  43
  44
  45
  46 #define S5(x) pgm_read_dword(&s5[(x)])
  47 #define S6(x) pgm_read_dword(&s6[(x)])
  48 #define S7(x) pgm_read_dword(&s7[(x)])
  49 #define S8(x) pgm_read_dword(&s8[(x)])
  50
  51 static
  52 void cast5_init_A(uint8_t *dest, uint8_t *src, bool bmode){
  53         uint8_t mask = bmode?0x8:0;
  54         *((uint32_t*)(&dest[0x0])) = *((uint32_t*)(&src[0x0^mask]))
  55                                      ^ S5(src[0xD^mask]) ^ S6(src[0xF^mask])
  56                                      ^ S7(src[0xC^mask]) ^ S8(src[0xE^mask])
  57                                      ^ S7(src[0x8^mask]);
  58         *((uint32_t*)(&dest[0x4])) = *((uint32_t*)(&src[0x8^mask]))
  59                                      ^ S5(dest[0x0]) ^ S6(dest[0x2])
  60                                      ^ S7(dest[0x1]) ^ S8(dest[0x3])
  61                                      ^ S8(src[0xA^mask]);
  62         *((uint32_t*)(&dest[0x8])) = *((uint32_t*)(&src[0xC^mask]))
  63                                      ^ S5(dest[0x7]) ^ S6(dest[0x6])
  64                                      ^ S7(dest[0x5]) ^ S8(dest[0x4])
  65                                      ^ S5(src[0x9^mask]);
  66         *((uint32_t*)(&dest[0xC])) = *((uint32_t*)(&src[0x4^mask]))
  67                                      ^ S5(dest[0xA])
  68                                      ^ S6(dest[0x9])
  69                                      ^ S7(dest[0xB])
  70                                      ^ S8(dest[0x8])
  71                                      ^ S6(src[0xB^mask]);
  72 }
  73
  74 static
  75 void cast5_init_M(uint8_t *dest, uint8_t *src, bool nmode, bool xmode){
  76         uint8_t nmt[] = {0xB, 0xA, 0x9, 0x8,
  77                          0xF, 0xE, 0xD, 0xC,
  78                          0x3, 0x2, 0x1, 0x0,
  79                          0x7, 0x6, 0x5, 0x4}; /* nmode table */
  80         uint8_t xmt[4][4] = {{0x2, 0x6, 0x9, 0xC},
  81                              {0x8, 0xD, 0x3, 0x7},
  82                              {0x3, 0x7, 0x8, 0xD},
  83                              {0x9, 0xC, 0x2, 0x6}};
  84         #define NMT(x) (src[nmode?nmt[(x)]:(x)])
  85         #define XMT(x) (src[xmt[(xmode<<1) + nmode][(x)]])
  86         *((uint32_t*)(&dest[0x0])) = S5(NMT(0x8)) ^ S6(NMT(0x9)) ^ S7(NMT(0x7)) ^ S8(NMT(0x6)) ^ S5(XMT(0));
  87         *((uint32_t*)(&dest[0x4])) = S5(NMT(0xA)) ^ S6(NMT(0xB)) ^ S7(NMT(0x5)) ^ S8(NMT(0x4)) ^ S6(XMT(1));
  88         *((uint32_t*)(&dest[0x8])) = S5(NMT(0xC)) ^ S6(NMT(0xD)) ^ S7(NMT(0x3)) ^ S8(NMT(0x2)) ^ S7(XMT(2));
  89         *((uint32_t*)(&dest[0xC])) = S5(NMT(0xE)) ^ S6(NMT(0xF)) ^ S7(NMT(0x1)) ^ S8(NMT(0x0)) ^ S8(XMT(3));
  90 }
  91
  92 #define S5B(x) pgm_read_byte(3+(uint8_t*)(&s5[(x)]))
  93 #define S6B(x) pgm_read_byte(3+(uint8_t*)(&s6[(x)]))
  94 #define S7B(x) pgm_read_byte(3+(uint8_t*)(&s7[(x)]))
  95 #define S8B(x) pgm_read_byte(3+(uint8_t*)(&s8[(x)]))
  96
  97 static
  98 void cast5_init_rM(uint8_t *klo, uint8_t *khi, uint8_t offset, uint8_t *src, bool nmode, bool xmode){
  99         uint8_t nmt[] = {0xB, 0xA, 0x9, 0x8, 0xF, 0xE, 0xD, 0xC, 0x3, 0x2, 0x1, 0x0, 0x7, 0x6, 0x5, 0x4}; /* nmode table */
 100         uint8_t xmt[4][4] = {{0x2, 0x6, 0x9, 0xC}, {0x8, 0xD, 0x3, 0x7}, {0x3, 0x7, 0x8, 0xD}, {0x9, 0xC, 0x2, 0x6}};
 101         uint8_t t, h=0;
 102         t = S5B(NMT(0x8)) ^ S6B(NMT(0x9)) ^ S7B(NMT(0x7)) ^ S8B(NMT(0x6)) ^ S5B(XMT(0));
 103                 klo[offset*2] |= (t & 0x0f);
 104                 h |= (t&0x10); h>>=1;
 105         t = S5B(NMT(0xA)) ^ S6B(NMT(0xB)) ^ S7B(NMT(0x5)) ^ S8B(NMT(0x4)) ^ S6B(XMT(1));
 106                 klo[offset*2] |= (t<<4) & 0xf0;
 107                 h |= t&0x10; h>>=1;
 108         t = S5B(NMT(0xC)) ^ S6B(NMT(0xD)) ^ S7B(NMT(0x3)) ^ S8B(NMT(0x2)) ^ S7B(XMT(2));
 109                 klo[offset*2+1] |= t&0xf;
 110                 h |= t&0x10; h>>=1;
 111         t = S5B(NMT(0xE)) ^ S6B(NMT(0xF)) ^ S7B(NMT(0x1)) ^ S8B(NMT(0x0)) ^ S8B(XMT(3));
 112                 klo[offset*2+1] |= t<<4;
 113                 h |= t&0x10; h >>=1;
 114         #ifdef DEBUG
 115                 uart_putstr("\r\n\t h="); uart_hexdump(&h,1);
 116         #endif
 117         khi[offset>>1] |= h<<((offset&0x1)?4:0);
 118 }
 119
 120 #define S_5X(s) pgm_read_dword(&s5[BPX[(s)]])
 121 #define S_6X(s) pgm_read_dword(&s6[BPX[(s)]])
 122 #define S_7X(s) pgm_read_dword(&s7[BPX[(s)]])
 123 #define S_8X(s) pgm_read_dword(&s8[BPX[(s)]])
 124
 125 #define S_5Z(s) pgm_read_dword(&s5[BPZ[(s)]])
 126 #define S_6Z(s) pgm_read_dword(&s6[BPZ[(s)]])
 127 #define S_7Z(s) pgm_read_dword(&s7[BPZ[(s)]])
 128 #define S_8Z(s) pgm_read_dword(&s8[BPZ[(s)]])
 129
 130
 131
 132
 133 void cast5_init(const void* key, uint16_t keylength_b, cast5_ctx_t* s){
 134          /* we migth return if the key is valid and if setup was sucessfull */
 135         uint32_t x[4], z[4];
 136         #define BPX ((uint8_t*)&(x[0]))
 137         #define BPZ ((uint8_t*)&(z[0]))
 138         s->shortkey = (keylength_b<=80);
 139         /* littel endian only! */
 140         memset(&(x[0]), 0 ,16); /* set x to zero */
 141         if(keylength_b > 128)
 142                 keylength_b=128;
 143         memcpy(&(x[0]), key, (keylength_b+7)/8);
 144
 145
 146         /* todo: merge a and b and compress the whole stuff */
 147         /***** A *****/
 148         cast5_init_A((uint8_t*)(&z[0]), (uint8_t*)(&x[0]), false);
 149         /***** M *****/
 150         cast5_init_M((uint8_t*)(&(s->mask[0])), (uint8_t*)(&z[0]), false, false);
 151         /***** B *****/
 152         cast5_init_A((uint8_t*)(&x[0]), (uint8_t*)(&z[0]), true);
 153         /***** N *****/
 154         cast5_init_M((uint8_t*)(&(s->mask[4])), (uint8_t*)(&x[0]), true, false);
 155         /***** A *****/
 156         cast5_init_A((uint8_t*)(&z[0]), (uint8_t*)(&x[0]), false);
 157         /***** N' *****/
 158         cast5_init_M((uint8_t*)(&(s->mask[8])), (uint8_t*)(&z[0]), true, true);
 159         /***** B *****/
 160         cast5_init_A((uint8_t*)(&x[0]), (uint8_t*)(&z[0]), true);
 161         /***** M' *****/
 162         cast5_init_M((uint8_t*)(&(s->mask[12])), (uint8_t*)(&x[0]), false, true);
 163
 164         /* that were the masking keys, now the rotation keys */
 165         /* set the keys to zero */
 166         memset(&(s->rotl[0]),0,8);
 167         s->roth[0]=s->roth[1]=0;
 168         /***** A *****/
 169         cast5_init_A((uint8_t*)(&z[0]), (uint8_t*)(&x[0]), false);
 170         /***** M *****/
 171         cast5_init_rM(&(s->rotl[0]), &(s->roth[0]), 0, (uint8_t*)(&z[0]), false, false);
 172         /***** B *****/
 173         cast5_init_A((uint8_t*)(&x[0]), (uint8_t*)(&z[0]), true);
 174         /***** N *****/
 175         cast5_init_rM(&(s->rotl[0]), &(s->roth[0]), 1, (uint8_t*)(&x[0]), true, false);
 176         /***** A *****/
 177         cast5_init_A((uint8_t*)(&z[0]), (uint8_t*)(&x[0]), false);
 178         /***** N' *****/
 179         cast5_init_rM(&(s->rotl[0]), &(s->roth[0]), 2, (uint8_t*)(&z[0]), true, true);
 180         /***** B *****/
 181         cast5_init_A((uint8_t*)(&x[0]), (uint8_t*)(&z[0]), true);
 182         /***** M' *****/
 183         cast5_init_rM(&(s->rotl[0]), &(s->roth[0]), 3, (uint8_t*)(&x[0]), false, true);
 184         /* done ;-) */
 185 }
 186
 187
 188
 189 /********************************************************************************************************/
 190
 191 #define ROTL32(a,n) ((a)<<(n) | (a)>>(32-(n)))
 192 #define CHANGE_ENDIAN32(x) ((x)<<24 | (x)>>24 | ((x)&0xff00)<<8 | ((x)&0xff0000)>>8 )
 193
 194 typedef uint32_t cast5_f_t(uint32_t,uint32_t,uint8_t);
 195
 196 #define IA 3
 197 #define IB 2
 198 #define IC 1
 199 #define ID 0
 200
 201 static
 202 uint32_t cast5_f1(uint32_t d, uint32_t m, uint8_t r){
 203         uint32_t t;
 204         t = ROTL32((d + m),r);
 205 #ifdef DEBUG
 206         uint32_t ia,ib,ic,id;
 207         uart_putstr("\r\n f1("); uart_hexdump(&d, 4); uart_putc(',');
 208                 uart_hexdump(&m , 4); uart_putc(','); uart_hexdump(&r, 1);uart_putstr("): I=");
 209                 uart_hexdump(&t, 4);
 210         ia = pgm_read_dword(&s1[((uint8_t*)&t)[IA]] );
 211         ib = pgm_read_dword(&s2[((uint8_t*)&t)[IB]] );
 212         ic = pgm_read_dword(&s3[((uint8_t*)&t)[IC]] );
 213         id = pgm_read_dword(&s4[((uint8_t*)&t)[ID]] );
 214         uart_putstr("\r\n\tIA="); uart_hexdump(&ia, 4);
 215         uart_putstr("\r\n\tIB="); uart_hexdump(&ib, 4);
 216         uart_putstr("\r\n\tIC="); uart_hexdump(&ic, 4);
 217         uart_putstr("\r\n\tID="); uart_hexdump(&id, 4);
 218
 219         return (((ia ^ ib) - ic) + id);
 220
 221 #else
 222
 223         return (((  pgm_read_dword(&s1[((uint8_t*)&t)[IA]])
 224                   ^ pgm_read_dword(&s2[((uint8_t*)&t)[IB]]) )
 225                   - pgm_read_dword(&s3[((uint8_t*)&t)[IC]]) )
 226                   + pgm_read_dword(&s4[((uint8_t*)&t)[ID]]) );
 227
 228 #endif
 229 }
 230
 231 static
 232 uint32_t cast5_f2(uint32_t d, uint32_t m, uint8_t r){
 233         uint32_t t;
 234         t = ROTL32((d ^ m),r);
 235 #ifdef DEBUG
 236         uint32_t ia,ib,ic,id;
 237         uart_putstr("\r\n f2("); uart_hexdump(&d, 4); uart_putc(',');
 238                 uart_hexdump(&m , 4); uart_putc(','); uart_hexdump(&r, 1);uart_putstr("): I=");
 239                 uart_hexdump(&t, 4);
 240
 241         ia = pgm_read_dword(&s1[((uint8_t*)&t)[IA]] );
 242         ib = pgm_read_dword(&s2[((uint8_t*)&t)[IB]] );
 243         ic = pgm_read_dword(&s3[((uint8_t*)&t)[IC]] );
 244         id = pgm_read_dword(&s4[((uint8_t*)&t)[ID]] );
 245
 246         uart_putstr("\r\n\tIA="); uart_hexdump(&ia, 4);
 247         uart_putstr("\r\n\tIB="); uart_hexdump(&ib, 4);
 248         uart_putstr("\r\n\tIC="); uart_hexdump(&ic, 4);
 249         uart_putstr("\r\n\tID="); uart_hexdump(&id, 4);
 250
 251         return (((ia - ib) + ic) ^ id);
 252 #else
 253
 254         return (((    pgm_read_dword(&s1[((uint8_t*)&t)[IA]])
 255                     - pgm_read_dword(&s2[((uint8_t*)&t)[IB]]) )
 256                     + pgm_read_dword(&s3[((uint8_t*)&t)[IC]]) )
 257                     ^ pgm_read_dword(&s4[((uint8_t*)&t)[ID]]) );
 258
 259 #endif
 260 }
 261
 262 static
 263 uint32_t cast5_f3(uint32_t d, uint32_t m, uint8_t r){
 264         uint32_t t;
 265         t = ROTL32((m - d),r);
 266
 267 #ifdef DEBUG
 268         uint32_t ia,ib,ic,id;
 269
 270         uart_putstr("\r\n f3("); uart_hexdump(&d, 4); uart_putc(',');
 271                 uart_hexdump(&m , 4); uart_putc(','); uart_hexdump(&r, 1);uart_putstr("): I=");
 272                 uart_hexdump(&t, 4);
 273
 274         ia = pgm_read_dword(&s1[((uint8_t*)&t)[IA]] );
 275         ib = pgm_read_dword(&s2[((uint8_t*)&t)[IB]] );
 276         ic = pgm_read_dword(&s3[((uint8_t*)&t)[IC]] );
 277         id = pgm_read_dword(&s4[((uint8_t*)&t)[ID]] );
 278
 279         uart_putstr("\r\n\tIA="); uart_hexdump(&ia, 4);
 280         uart_putstr("\r\n\tIB="); uart_hexdump(&ib, 4);
 281         uart_putstr("\r\n\tIC="); uart_hexdump(&ic, 4);
 282         uart_putstr("\r\n\tID="); uart_hexdump(&id, 4);
 283         return (((ia + ib) ^ ic) - id);
 284 #else
 285         return ((  pgm_read_dword(&s1[((uint8_t*)&t)[IA]] )
 286                  + pgm_read_dword(&s2[((uint8_t*)&t)[IB]] ))
 287                  ^ pgm_read_dword(&s3[((uint8_t*)&t)[IC]] ))
 288                  - pgm_read_dword(&s4[((uint8_t*)&t)[ID]] );
 289
 290 #endif
 291 }
 292
 293 /******************************************************************************/
 294
 295 void cast5_enc(void* block, const cast5_ctx_t *s){
 296         uint32_t l,r, x, y;
 297         uint8_t i;
 298         cast5_f_t* f[]={cast5_f1,cast5_f2,cast5_f3};
 299         l=((uint32_t*)block)[0];
 300         r=((uint32_t*)block)[1];
 301 //      uart_putstr("\r\n round[-1] = ");
 302 //      uart_hexdump(&r, 4);
 303         for (i=0;i<(s->shortkey?12:16);++i){
 304                 x = r;
 305                 y = (f[i%3])(CHANGE_ENDIAN32(r), CHANGE_ENDIAN32(s->mask[i]),
 306                         (((s->roth[i>>3]) & (1<<(i&0x7)))?0x10:0x00)
 307                          + ( ((s->rotl[i>>1])>>((i&1)?4:0)) & 0x0f) );
 308                 r = l ^ CHANGE_ENDIAN32(y);
 309 //              uart_putstr("\r\n round["); DEBUG_B(i); uart_putstr("] = ");
 310 //              uart_hexdump(&r, 4);
 311                 l = x;
 312         }
 313         ((uint32_t*)block)[0]=r;
 314         ((uint32_t*)block)[1]=l;
 315 }
 316
 317 /******************************************************************************/
 318
 319 void cast5_dec(void* block, const cast5_ctx_t *s){
 320         uint32_t l,r, x, y;
 321         int8_t i, rounds;
 322         cast5_f_t* f[]={cast5_f1,cast5_f2,cast5_f3};
 323         l=((uint32_t*)block)[0];
 324         r=((uint32_t*)block)[1];
 325         rounds = (s->shortkey?12:16);
 326         for (i=rounds-1; i>=0 ;--i){
 327                 x = r;
 328                 y = (f[i%3])(CHANGE_ENDIAN32(r), CHANGE_ENDIAN32(s->mask[i]),
 329                         (((s->roth[i>>3]) & (1<<(i&0x7)))?0x10:0x00)
 330                          + ( ((s->rotl[i>>1])>>((i&1)?4:0)) & 0x0f) );
 331                 r = l ^ CHANGE_ENDIAN32(y);
 332                 l = x;
 333         }
 334         ((uint32_t*)block)[0]=r;
 335         ((uint32_t*)block)[1]=l;
 336 }
 337
 338
 339 /******************************************************************************/
 340
 341
 342
 343