--- /dev/null
+/* dsa_sign.c */
+/*
+ This file is part of the ARM-Crypto-Lib.
+ Copyright (C) 2006-2010 Daniel Otte (daniel.otte@rub.de)
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <stdint.h>
+#include <string.h>
+#include "bigint.h"
+#include "dsa.h"
+#include "hashfunction_descriptor.h"
+#include "hfal-basic.h"
+
+#define MAX(a,b) (((a)>(b))?(a):(b))
+
+uint8_t dsa_sign_bigint(dsa_signature_t* s, const bigint_t* m,
+ const dsa_ctx_t* ctx, const bigint_t* k){
+ bigint_t tmp, tmp2;
+ bigint_word_t tmp_b[ctx->domain.p.length_W+5], tmp2_b[ctx->domain.q.length_W+5];
+ tmp.wordv= tmp_b;
+ tmp2.wordv = tmp2_b;
+ bigint_expmod_u(&tmp, &(ctx->domain.g), k, &(ctx->domain.p));
+ bigint_reduce(&tmp, &(ctx->domain.q));
+ bigint_copy(&(s->r), &tmp);
+ bigint_mul_u(&tmp, &tmp, &(ctx->priv));
+ bigint_add_u(&tmp, &tmp, m);
+ bigint_inverse(&tmp2, k, &(ctx->domain.q));
+ bigint_mul_u(&tmp, &tmp, &tmp2);
+ bigint_reduce(&tmp, &(ctx->domain.q));
+ bigint_copy(&(s->s), &tmp);
+
+ if(s->s.length_W==0 || s->r.length_W==0){
+ return 1;
+ }
+
+ return 0;
+}
+
+uint8_t dsa_sign_message(dsa_signature_t* s, const void* m, uint16_t m_len_b,
+ const hfdesc_t* hash_desc, const dsa_ctx_t* ctx,
+ uint8_t(*rand_in)(void)){
+ bigint_t z, k;
+ uint16_t i, n_B = ctx->domain.q.length_W;
+ unsigned hash_length = MAX(n_B,(hfal_hash_getHashsize(hash_desc)+sizeof(bigint_word_t)*8-1)/(sizeof(bigint_word_t)*8));
+ bigint_word_t hash_value[hash_length];
+ bigint_word_t k_b[n_B];
+ memset(hash_value, 0, hash_length*sizeof(bigint_word_t));
+ hfal_hash_mem(hash_desc, hash_value, m, m_len_b);
+ z.wordv = hash_value;
+ z.length_W = n_B;
+ bigint_changeendianess(&z);
+ k.wordv = k_b;
+ k.length_W = n_B;
+ do{
+ for(i=0; i<n_B*sizeof(bigint_word_t); ++i){
+ ((uint8_t*)k_b)[i] = rand_in();
+ }
+ k.length_W = n_B;
+ bigint_adjust(&k);
+ }while(dsa_sign_bigint(s, &z, ctx, &k));
+ return 0;
+}
+