X-Git-Url: https://git.cryptolib.org/?p=arm-crypto-lib.git;a=blobdiff_plain;f=dsa%2Fdsa_sign.c;fp=dsa%2Fdsa_sign.c;h=e8c826ab308057cdd7f00a67f42368518edb981c;hp=0000000000000000000000000000000000000000;hb=2a4779378a7bf4322a0e6b2024284092135e8a3d;hpb=e69f1207a9fbd9c0f45bfdbb2d8ebe9852d95969

diff --git a/dsa/dsa_sign.c b/dsa/dsa_sign.c
new file mode 100644
index 0000000..e8c826a
--- /dev/null
+++ b/dsa/dsa_sign.c
@@ -0,0 +1,76 @@
+/* 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;
+}
+