122 lines
3.5 KiB
C
122 lines
3.5 KiB
C
/* ecdsa.c */
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/*
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This file is part of the AVR-Crypto-Lib.
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Copyright (C) 2006-2012 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 <stdlib.h>
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#include <inttypes.h>
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#include "bigint.h"
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#include "ecc.h"
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#include "random_dummy.h"
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#include "ecdsa.h"
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#include "hfal-basic.h"
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uint8_t ecdsa_signature_alloc(ecdsa_signature_t* s, size_t length_B){
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if(!(s->r.wordv = malloc(length_B))){
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return 1;
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}
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if(!(s->s.wordv = malloc(length_B))){
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free(s->r.wordv);
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return 1;
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}
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bigint_set_zero(&s->r);
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bigint_set_zero(&s->s);
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return 0;
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}
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void ecdsa_signature_free(ecdsa_signature_t* s){
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free(s->r.wordv);
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free(s->s.wordv);
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}
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uint8_t ecdsa_sign_bigint(ecdsa_signature_t* s, const bigint_t* m,
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const ecdsa_ctx_t* ctx, const bigint_t* k){
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bigint_t t;
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ecc_combi_point_t q;
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if(!(t.wordv = malloc(ctx->curve->p->length_W * 2 * sizeof(bigint_word_t)))){
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return 1;
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}
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if(!ecc_chudnovsky_point_alloc(&q.chudnovsky, ctx->curve->p->length_W * sizeof(bigint_word_t))){
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free(t.wordv);
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return 1;
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}
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ecc_chudnovsky_multiplication(&q.chudnovsky, k, ctx->basepoint, ctx->curve);
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if(q.chudnovsky.x.length_W == 0){
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return 2;
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}
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ecc_chudnovsky_to_affine_point(&q.affine, &q.chudnovsky, ctx->curve);
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bigint_inverse(&s->r, k, ctx->curve->p);
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bigint_mul_u(&t, &q.affine.x, ctx->priv);
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ctx->curve->reduce_p(&t);
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bigint_add_u(&t, &t, m);
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ctx->curve->reduce_p(&t);
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bigint_mul_u(&t, &t, &s->r);
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ctx->curve->reduce_p(&t);
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if(t.length_W == 0){
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return 2;
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}
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bigint_copy(&s->r, &q.affine.x);
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bigint_copy(&s->s, &t);
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ecc_chudnovsky_point_free(&q.chudnovsky);
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free(t.wordv);
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return 0;
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}
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uint8_t ecdsa_sign_message(ecdsa_signature_t* s, const void* m, uint16_t m_len_b,
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const hfdesc_t* hash_desc, const ecdsa_ctx_t* ctx,
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const void *rand_in){
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bigint_t m_int;
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bigint_t r_int;
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uint8_t r;
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if(rand_in == NULL){
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if(!(r_int.wordv = malloc(ctx->curve->p->length_W * sizeof(bigint_word_t)))){
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return 1;
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}
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}
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if(!(m_int.wordv = malloc(hfal_hash_getHashsize(hash_desc) / 8))){
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if(rand_in == NULL){
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free(r_int.wordv);
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}
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return 1;
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}
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hfal_hash_mem(hash_desc, m_int.wordv, m, m_len_b);
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do{
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if(rand_in == NULL){
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size_t i;
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do{
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i = ctx->curve->p->length_W * sizeof(bigint_word_t) - 1;
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r_int.length_W = ctx->curve->p->length_W;
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do{
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((uint8_t*)r_int.wordv)[i] = prng_get_byte();
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}while(i--);
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bigint_adjust(&r_int);
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}while(bigint_cmp_u(&r_int, ctx->curve->p) >= 0);
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}
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}while((r = ecdsa_sign_bigint(s, &m_int, ctx, &r_int)) == 2 && (rand_in == NULL));
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return r;
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}
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