137 lines
3.6 KiB
C
137 lines
3.6 KiB
C
/* rsa_basic.c */
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/*
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This file is part of the ARM-Crypto-Lib.
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Copyright (C) 2006-2011 Daniel Otte (daniel.otte@rub.de)
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include "bigint.h"
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#include "bigint_io.h"
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#include "rsa_basic.h"
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#include "cli.h"
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#include "uart_lowlevel.h"
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void rsa_enc(bigint_t* data, rsa_publickey_t* key){
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/*
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cli_putstr("\r\n -->rsa_enc()\r\n m = ");
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bigint_print_hex(data);
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cli_putstr("\r\n e = ");
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bigint_print_hex(key->exponent);
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cli_putstr("\r\n n = ");
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bigint_print_hex(key->modulus);
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*/
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bigint_expmod_u(data, data, key->exponent, key->modulus);
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}
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/*
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(p,q,dp,dq,qinv)
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m1 = c**dp % p
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m2 = c**dq % q
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h = (m1 - m2) * qinv % p
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m = m2 + q * h
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*/
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uint8_t rsa_dec_crt_mono(bigint_t* data, rsa_privatekey_t* key){
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bigint_t m1, m2;
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m1.wordv = malloc(key->components[0]->length_B * sizeof(bigint_word_t));
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m2.wordv = malloc(key->components[1]->length_B * sizeof(bigint_word_t));
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if(!m1.wordv || !m2.wordv){
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cli_putstr("\r\nERROR: OOM!");
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free(m1.wordv);
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free(m2.wordv);
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return 1;
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}
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bigint_expmod_u(&m1, data, key->components[2], key->components[0]);
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bigint_expmod_u(&m2, data, key->components[3], key->components[1]);
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bigint_sub_s(&m1, &m1, &m2);
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while(BIGINT_NEG_MASK & m1.info){
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bigint_add_s(&m1, &m1, key->components[0]);
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}
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bigint_reduce(&m1, key->components[0]);
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bigint_mul_u(data, &m1, key->components[4]);
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bigint_reduce(data, key->components[0]);
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bigint_mul_u(data, data, key->components[1]);
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bigint_add_u(data, data, &m2);
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free(m1.wordv);
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free(m2.wordv);
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return 0;
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}
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uint8_t rsa_dec(bigint_t* data, rsa_privatekey_t* key){
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if(key->n == 1){
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bigint_expmod_u(data, data, key->components[0], key->modulus);
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return 0;
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}
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if(key->n == 5){
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if (rsa_dec_crt_mono(data, key)){
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return 3;
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}
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return 0;
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}
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if(key->n<8 || (key->n-5)%3 != 0){
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return 1;
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}
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//rsa_dec_crt_multi(data, key, (key->n-5)/3);
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return 2;
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}
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void rsa_os2ip(bigint_t* dest, const void* data, uint32_t length_B){
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uint8_t off;
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off = length_B % sizeof(bigint_word_t);
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if(!data){
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if(off){
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dest->wordv = realloc(dest->wordv, length_B + sizeof(bigint_word_t) - off);
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memmove((uint8_t*)dest->wordv+off, dest->wordv, length_B);
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memset(dest->wordv, 0, off);
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}
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}else{
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if(off){
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memcpy((uint8_t*)dest->wordv + off, data, length_B);
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memset(dest, 0, off);
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}else{
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memcpy(dest->wordv, data, length_B);
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}
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}
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dest->length_B = (length_B + sizeof(bigint_word_t) - 1) / sizeof(bigint_word_t);
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bigint_changeendianess(dest);
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bigint_adjust(dest);
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}
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void rsa_i2osp(void* dest, bigint_t* src, uint16_t* out_length_B){
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*out_length_B = bigint_get_first_set_bit(src) / 8 + 1;
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if(dest){
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uint16_t i;
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for(i=*out_length_B; i>0; --i){
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*((uint8_t*)dest) = ((uint8_t*)src->wordv)[i-1];
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dest = (uint8_t*)dest + 1;
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}
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}else{
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uint8_t off;
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bigint_changeendianess(src);
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bigint_adjust(src);
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off = bigint_get_last_set_bit(src)/8;
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if(off){
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memmove(src->wordv, (uint8_t*)src->wordv+off, *out_length_B);
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}
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}
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}
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