]> git.cryptolib.org Git - arm-crypto-lib.git/blob - rsa/rsa_basic.c
works with three tests; contains a lot debug foo
[arm-crypto-lib.git] / 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 #include "cli.h"
28 #include "uart_lowlevel.h"
29
30 void rsa_enc(bigint_t* data, rsa_publickey_t* key){
31         cli_putstr("\r\n -->rsa_enc()\r\n m = ");
32         bigint_print_hex(data);
33         cli_putstr("\r\n e = ");
34         bigint_print_hex(key->exponent);
35         cli_putstr("\r\n n = ");
36         bigint_print_hex(key->modulus);
37         bigint_expmod_u(data, data, key->exponent, key->modulus);
38 }
39
40 /*
41 (p,q,dp,dq,qinv)
42 m1 = c**dp % p
43 m2 = c**dq % q
44 h = (m1 - m2) * qinv % p
45 m = m2 + q * h
46 */
47
48 uint8_t rsa_dec_crt_mono(bigint_t* data, rsa_privatekey_t* key){
49         bigint_t m1, m2;
50         cli_putstr("\r\n --> rsa_dec_crt_mono()");
51         uart_flush(0);
52         m1.wordv = malloc(key->components[0]->length_B * sizeof(bigint_word_t));
53         m2.wordv = malloc(key->components[1]->length_B * sizeof(bigint_word_t));
54         if(!m1.wordv || !m2.wordv){
55                 cli_putstr("\r\nERROR: OOM!");
56                 free(m1.wordv);
57                 free(m2.wordv);
58                 return 1;
59         }
60         cli_putc('a'); uart_flush(0);
61         bigint_expmod_u(&m1, data, key->components[2], key->components[0]);
62         cli_putc('f'); uart_flush(0);
63         bigint_expmod_u(&m2, data, key->components[3], key->components[1]);
64         cli_putc('b'); uart_flush(0);
65         bigint_sub_s(&m1, &m1, &m2);
66         while(BIGINT_NEG_MASK & m1.info){
67                 bigint_add_s(&m1, &m1, key->components[0]);
68         }
69
70         cli_putc('c'); uart_flush(0);
71         bigint_reduce(&m1, key->components[0]);
72         bigint_mul_u(data, &m1, key->components[4]);
73         cli_putc('d'); uart_flush(0);
74         bigint_reduce(data, key->components[0]);
75         bigint_mul_u(data, data, key->components[1]);
76         bigint_add_u(data, data, &m2);
77         cli_putc('e'); uart_flush(0);
78         free(m1.wordv);
79         free(m2.wordv);
80         return 0;
81 }
82
83 uint8_t rsa_dec(bigint_t* data, rsa_privatekey_t* key){
84         if(key->n == 1){
85                 bigint_expmod_u(data, data, key->components[0], key->modulus);
86                 return 0;
87         }
88         if(key->n == 5){
89                 if (rsa_dec_crt_mono(data, key)){
90                         return 3;
91                 }
92                 return 0;
93         }
94         if(key->n<8 || (key->n-5)%3 != 0){
95                 return 1;
96         }
97         //rsa_dec_crt_multi(data, key, (key->n-5)/3);
98         return 2;
99 }
100
101 void rsa_os2ip(bigint_t* dest, const void* data, uint32_t length_B){
102         uint8_t off;
103         off = length_B % sizeof(bigint_word_t);
104         if(!data){
105                 if(off){
106                         dest->wordv = realloc(dest->wordv, length_B + sizeof(bigint_word_t) - off);
107                         memmove((uint8_t*)dest->wordv+off, dest->wordv, length_B);
108                         memset(dest->wordv, 0, off);
109                 }
110         }else{
111                 if(off){
112                         memcpy((uint8_t*)dest->wordv + off, data, length_B);
113                         memset(dest, 0, off);
114                 }else{
115                         memcpy(dest->wordv, data, length_B);
116                 }
117         }
118         dest->length_B = (length_B + sizeof(bigint_word_t) - 1) / sizeof(bigint_word_t);
119         bigint_changeendianess(dest);
120         bigint_adjust(dest);
121 }
122
123 void rsa_i2osp(void* dest, bigint_t* src, uint16_t* out_length_B){
124         *out_length_B = bigint_get_first_set_bit(src) / 8 + 1;
125         if(dest){
126                 uint16_t i;
127                 for(i=*out_length_B; i>0; --i){
128                         *((uint8_t*)dest) = ((uint8_t*)src->wordv)[i-1];
129                         dest = (uint8_t*)dest + 1;
130                 }
131         }else{
132                 uint8_t off;
133                 bigint_changeendianess(src);
134                 bigint_adjust(src);
135
136                 off = bigint_get_last_set_bit(src)/8;
137                 if(off){
138                         memmove(src->wordv, (uint8_t*)src->wordv+off, *out_length_B);
139                 }
140         }
141 }
142