3 This file is part of the AVR-Crypto-Lib.
4 Copyright (C) 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 uint8_t dsa_sign_bigint(dsa_signature_t* s, const bigint_t* m,
28 const dsa_ctx_t* ctx, const bigint_t* k){
30 uint8_t tmp_b[ctx->domain.p.length_W+5], tmp2_b[ctx->domain.q.length_W+5];
33 bigint_expmod_u(&tmp, &(ctx->domain.g), k, &(ctx->domain.p));
34 bigint_reduce(&tmp, &(ctx->domain.q));
35 bigint_copy(&(s->r), &tmp);
36 bigint_mul_u(&tmp, &tmp, &(ctx->priv));
37 bigint_add_u(&tmp, &tmp, m);
38 bigint_inverse(&tmp2, k, &(ctx->domain.q));
39 bigint_mul_u(&tmp, &tmp, &tmp2);
40 bigint_reduce(&tmp, &(ctx->domain.q));
41 bigint_copy(&(s->s), &tmp);
43 if(s->s.length_W==0 || s->r.length_W==0){
50 uint8_t dsa_sign_message(dsa_signature_t* s, const void* m, uint16_t m_len_b,
51 const hfdesc_t* hash_desc, const dsa_ctx_t* ctx,
52 const rand_func_ptr_t rand_in){
54 uint8_t i, n_B = ctx->domain.q.length_W;
55 uint8_t hash_value[(n_B>(hfal_hash_getHashsize(hash_desc)+7)/8)?n_B:(hfal_hash_getHashsize(hash_desc)+7)/8];
57 hfal_hash_mem(hash_desc, hash_value, m, m_len_b);
60 bigint_changeendianess(&z);
69 }while(dsa_sign_bigint(s, &z, ctx, &k));
70 cli_putstr_P(PSTR("\r\nsignature computed"));