3 This file is part of the ARM-Crypto-Lib.
4 Copyright (C) 2006-2010 Daniel Otte (daniel.otte@rub.de)
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.
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.
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/>.
24 #include "hashfunction_descriptor.h"
25 #include "hfal-basic.h"
27 #define MAX(a,b) (((a)>(b))?(a):(b))
29 uint8_t dsa_sign_bigint(dsa_signature_t* s, const bigint_t* m,
30 const dsa_ctx_t* ctx, const bigint_t* k){
32 bigint_word_t tmp_b[ctx->domain.p.length_W+5], tmp2_b[ctx->domain.q.length_W+5];
35 bigint_expmod_u(&tmp, &(ctx->domain.g), k, &(ctx->domain.p));
36 bigint_reduce(&tmp, &(ctx->domain.q));
37 bigint_copy(&(s->r), &tmp);
38 bigint_mul_u(&tmp, &tmp, &(ctx->priv));
39 bigint_add_u(&tmp, &tmp, m);
40 bigint_inverse(&tmp2, k, &(ctx->domain.q));
41 bigint_mul_u(&tmp, &tmp, &tmp2);
42 bigint_reduce(&tmp, &(ctx->domain.q));
43 bigint_copy(&(s->s), &tmp);
45 if(s->s.length_W==0 || s->r.length_W==0){
52 uint8_t dsa_sign_message(dsa_signature_t* s, const void* m, uint16_t m_len_b,
53 const hfdesc_t* hash_desc, const dsa_ctx_t* ctx,
54 uint8_t(*rand_in)(void)){
56 uint16_t i, n_B = ctx->domain.q.length_W;
57 unsigned hash_length = MAX(n_B,(hfal_hash_getHashsize(hash_desc)+sizeof(bigint_word_t)*8-1)/(sizeof(bigint_word_t)*8));
58 bigint_word_t hash_value[hash_length];
59 bigint_word_t k_b[n_B];
60 memset(hash_value, 0, hash_length*sizeof(bigint_word_t));
61 hfal_hash_mem(hash_desc, hash_value, m, m_len_b);
64 bigint_changeendianess(&z);
68 for(i=0; i<n_B*sizeof(bigint_word_t); ++i){
69 ((uint8_t*)k_b)[i] = rand_in();
73 }while(dsa_sign_bigint(s, &z, ctx, &k));