rsa/rsa_basic.c

   1 /* rsa_basic.c */
   2 /*
   3     This file is part of the ARM-Crypto-Lib.
   4     Copyright (C) 2006-2011 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 #include <stdint.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include "bigint.h"
  24 #include "bigint_io.h"
  25 #include "rsa_basic.h"
  26
  27 #define DEBUG 0
  28
  29 #if DEBUG
  30 #include "cli.h"
  31 #endif
  32
  33 void rsa_enc(bigint_t* data, rsa_publickey_t* key){
  34 /*
  35         cli_putstr_P(PSTR("\r\n -->rsa_enc()\r\n m = "));
  36         bigint_print_hex(data);
  37         cli_putstr_P(PSTR("\r\n e = "));
  38         bigint_print_hex(key->exponent);
  39         cli_putstr_P(PSTR("\r\n n = "));
  40         bigint_print_hex(key->modulus);
  41 */
  42         bigint_expmod_u(data, data, &key->exponent, &key->modulus);
  43 }
  44
  45 /*
  46 (p,q,dp,dq,qinv)
  47 m1 = c**dp % p
  48 m2 = c**dq % q
  49 h = (m1 - m2) * qinv % p
  50 m = m2 + q * h
  51 */
  52
  53 uint8_t rsa_dec_crt_mono(bigint_t* data, rsa_privatekey_t* key){
  54         bigint_t m1, m2;
  55         m1.wordv = malloc((key->components[0].length_B + 1) * sizeof(bigint_word_t));
  56         m2.wordv = malloc((key->components[1].length_B + 1) * sizeof(bigint_word_t));
  57         if(!m1.wordv || !m2.wordv){
  58 #if DEBUG
  59                 cli_putstr_P(PSTR("\r\nERROR: OOM!"));
  60 #endif
  61                 free(m1.wordv);
  62                 free(m2.wordv);
  63                 return 1;
  64         }
  65 #if DEBUG
  66         cli_putstr_P(PSTR("\r\nDBG: expmod m1 ..."));
  67         cli_putstr_P(PSTR("\r\nexpmod("));
  68         bigint_print_hex(data);
  69         cli_putc(',');
  70         bigint_print_hex(&(key->components[2]));
  71         cli_putc(',');
  72         bigint_print_hex(&(key->components[0]));
  73         cli_putstr_P(PSTR(") = "));
  74 #endif
  75         bigint_expmod_u(&m1, data, &(key->components[2]), &(key->components[0]));
  76 #if DEBUG
  77         bigint_print_hex(&m1);
  78         cli_putstr_P(PSTR("expmod m2 ..."));
  79         cli_putstr_P(PSTR("\r\nexpmod("));
  80         bigint_print_hex(data);
  81         cli_putc(',');
  82         bigint_print_hex(&(key->components[3]));
  83         cli_putc(',');
  84         bigint_print_hex(&(key->components[1]));
  85         cli_putstr_P(PSTR(") = "));
  86 #endif
  87         bigint_expmod_u(&m2, data, &(key->components[3]), &(key->components[1]));
  88 #if DEBUG
  89         bigint_print_hex(&m2);
  90         cli_putstr_P(PSTR("\r\nDBG: sub ..."));
  91         cli_putstr_P(PSTR("\r\nsub("));
  92         bigint_print_hex(&m1);
  93         cli_putc(',');
  94         bigint_print_hex(&m2);
  95         cli_putstr_P(PSTR(") = "));
  96 #endif
  97         bigint_sub_s(&m1, &m1, &m2);
  98 #if DEBUG
  99         bigint_print_hex(&m1);
 100 #endif
 101         while(BIGINT_NEG_MASK & m1.info){
 102 #if DEBUG
 103         cli_putstr_P(PSTR("\r\nDBG: adding "));
 104         bigint_print_hex(key->components[0]);
 105         cli_putstr_P(PSTR("\r\nDBG: to "));
 106         bigint_print_hex(&m1);
 107 #endif
 108                 bigint_add_s(&m1, &m1, &(key->components[0]));
 109         }
 110 #if DEBUG
 111         cli_putstr_P(PSTR("\r\nDBG: reduce-mul ..."));
 112         cli_putstr_P(PSTR("\r\nreduce("));
 113         bigint_print_hex(&m1);
 114         cli_putc(',');
 115         bigint_print_hex(&(key->components[0]));
 116         cli_putstr_P(PSTR(") = "));
 117 #endif
 118         bigint_reduce(&m1, &(key->components[0]));
 119 #if DEBUG
 120         bigint_print_hex(&m1);
 121         cli_putstr_P(PSTR("\r\nmul("));
 122         bigint_print_hex(&m1);
 123         cli_putc(',');
 124         bigint_print_hex(&(key->components[4]));
 125         cli_putstr_P(PSTR(") = "));
 126 #endif
 127         bigint_mul_u(data, &m1, &(key->components[4]));
 128 #if DEBUG
 129         bigint_print_hex(data);
 130         cli_putstr_P(PSTR("\r\nreduce("));
 131         bigint_print_hex(data);
 132         cli_putc(',');
 133         bigint_print_hex(&(key->components[0]));
 134         cli_putstr_P(PSTR(") = "));
 135 #endif
 136         bigint_reduce(data, &(key->components[0]));
 137 #if DEBUG
 138         bigint_print_hex(data);
 139         cli_putstr_P(PSTR("\r\nmul("));
 140         bigint_print_hex(data);
 141         cli_putc(',');
 142         bigint_print_hex(&(key->components[1]));
 143         cli_putstr_P(PSTR(") = "));
 144 #endif
 145         bigint_mul_u(data, data, &(key->components[1]));
 146 #if DEBUG
 147         bigint_print_hex(data);
 148         cli_putstr_P(PSTR("\r\nadd("));
 149         bigint_print_hex(data);
 150         cli_putc(',');
 151         bigint_print_hex(&m2);
 152         cli_putstr_P(PSTR(") = "));
 153 #endif
 154         bigint_add_u(data, data, &m2);
 155 #if DEBUG
 156         bigint_print_hex(data);
 157 #endif
 158         free(m2.wordv);
 159         free(m1.wordv);
 160         return 0;
 161 }
 162
 163 uint8_t rsa_dec(bigint_t* data, rsa_privatekey_t* key){
 164         if(key->n == 1){
 165                 bigint_expmod_u(data, data, &(key->components[0]), &key->modulus);
 166                 return 0;
 167         }
 168         if(key->n == 5){
 169                 if (rsa_dec_crt_mono(data, key)){
 170                         return 3;
 171                 }
 172                 return 0;
 173         }
 174         if(key->n<8 || (key->n-5)%3 != 0){
 175                 return 1;
 176         }
 177         //rsa_dec_crt_multi(data, key, (key->n-5)/3);
 178         return 2;
 179 }
 180
 181 void rsa_os2ip(bigint_t* dest, const void* data, uint32_t length_B){
 182 #if BIGINT_WORD_SIZE == 8
 183         if(data){
 184                 memcpy(dest->wordv, data, length_B);
 185         }
 186         dest->length_B = length_B;
 187 #else
 188         uint8_t off;
 189         off = (sizeof(bigint_word_t) - length_B % sizeof(bigint_word_t)) % sizeof(bigint_word_t);
 190 #if DEBUG
 191         cli_putstr_P(PSTR("\r\nDBG: off = 0x"));
 192         cli_hexdump_byte(off);
 193 #endif
 194         if(!data){
 195                 if(off){
 196                         dest->wordv = realloc(dest->wordv, length_B + sizeof(bigint_word_t) - off);
 197                         memmove((uint8_t*)dest->wordv+off, dest->wordv, length_B);
 198                         memset(dest->wordv, 0, off);
 199                 }
 200         }else{
 201                 memcpy((uint8_t*)dest->wordv + off, data, length_B);
 202                 if(off){
 203                         memset(dest->wordv, 0, off);
 204                 }
 205         }
 206         dest->length_B = (length_B + off) / sizeof(bigint_word_t);
 207 #if DEBUG
 208         cli_putstr_P(PSTR("\r\nDBG: dest->length_B = 0x"));
 209         cli_hexdump_rev(&(dest->length_B), 2);
 210 #endif
 211 #endif
 212         dest->info = 0;
 213         bigint_changeendianess(dest);
 214         bigint_adjust(dest);
 215 }
 216
 217 void rsa_i2osp(void* dest, bigint_t* src, uint16_t* out_length_B){
 218 #if BIGINT_WORD_SIZE == 8
 219         if(dest){
 220                 uint8_t *e = src->wordv + src->length_B;
 221                 uint16_t i;
 222                 for(i=src->length_B; i>0; --i){
 223                         *((uint8_t*)dest) = *--e;
 224                         dest = (uint8_t*)dest + 1;
 225                 }
 226         }else{
 227                 bigint_changeendianess(src);
 228         }
 229
 230         *out_length_B = src->length_B;
 231 #else
 232         *out_length_B = bigint_get_first_set_bit(src) / 8 + 1;
 233         if(dest){
 234                 uint16_t i;
 235                 for(i=*out_length_B; i>0; --i){
 236                         *((uint8_t*)dest) = ((uint8_t*)src->wordv)[i-1];
 237                         dest = (uint8_t*)dest + 1;
 238                 }
 239         }else{
 240                 uint8_t off;
 241                 bigint_changeendianess(src);
 242                 bigint_adjust(src);
 243
 244                 off = bigint_get_last_set_bit(src)/8;
 245                 if(off){
 246                         memmove(src->wordv, (uint8_t*)src->wordv+off, *out_length_B);
 247                 }
 248         }
 249 #endif
 250 }
 251