fixing and extending ecdsa

[avr-crypto-lib.git] / ecdsa / ecdsa_sign.c

diff --git a/ecdsa/ecdsa_sign.c b/ecdsa/ecdsa_sign.c
new file mode 100644 (file)
index 0000000..3a9fd21
--- /dev/null
+++ b/ecdsa/ecdsa_sign.c
@@ -0,0 +1,121 @@
+/* ecdsa.c */
+/*
+    This file is part of the AVR-Crypto-Lib.
+    Copyright (C) 2006-2012 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 <stdlib.h>
+#include <inttypes.h>
+#include "bigint.h"
+#include "ecc.h"
+#include "random_dummy.h"
+#include "ecdsa.h"
+#include "hfal-basic.h"
+
+uint8_t ecdsa_signature_alloc(ecdsa_signature_t* s, size_t length_B){
+    if(!(s->r.wordv = malloc(length_B))){
+        return 1;
+    }
+    if(!(s->s.wordv = malloc(length_B))){
+        free(s->r.wordv);
+        return 1;
+    }
+    bigint_set_zero(&s->r);
+    bigint_set_zero(&s->s);
+    return 0;
+}
+
+void ecdsa_signature_free(ecdsa_signature_t* s){
+    free(s->r.wordv);
+    free(s->s.wordv);
+}
+
+uint8_t ecdsa_sign_bigint(ecdsa_signature_t* s, const bigint_t* m,
+                          const ecdsa_ctx_t* ctx, const bigint_t* k){
+
+    bigint_t t;
+    ecc_combi_point_t q;
+
+
+    if(!(t.wordv = malloc(ctx->curve->p->length_W * 2 * sizeof(bigint_word_t)))){
+        return 1;
+    }
+    if(!ecc_chudnovsky_point_alloc(&q.chudnovsky, ctx->curve->p->length_W * sizeof(bigint_word_t))){
+        free(t.wordv);
+        return 1;
+    }
+
+    ecc_chudnovsky_multiplication(&q.chudnovsky, k, ctx->basepoint, ctx->curve);
+    if(q.chudnovsky.x.length_W == 0){
+        return 2;
+    }
+    ecc_chudnovsky_to_affine_point(&q.affine, &q.chudnovsky, ctx->curve);
+    bigint_inverse(&s->r, k, ctx->curve->p);
+    bigint_mul_u(&t, &q.affine.x, ctx->priv);
+    ctx->curve->reduce_p(&t);
+    bigint_add_u(&t, &t, m);
+    ctx->curve->reduce_p(&t);
+    bigint_mul_u(&t, &t, &s->r);
+    ctx->curve->reduce_p(&t);
+    if(t.length_W == 0){
+        return 2;
+    }
+    bigint_copy(&s->r, &q.affine.x);
+    bigint_copy(&s->s, &t);
+
+    ecc_chudnovsky_point_free(&q.chudnovsky);
+    free(t.wordv);
+
+    return 0;
+}
+uint8_t ecdsa_sign_message(ecdsa_signature_t* s, const void* m, uint16_t m_len_b,
+                           const hfdesc_t* hash_desc, const ecdsa_ctx_t* ctx,
+                           const void *rand_in){
+    bigint_t m_int;
+    bigint_t r_int;
+    uint8_t r;
+
+    if(rand_in == NULL){
+        if(!(r_int.wordv = malloc(ctx->curve->p->length_W * sizeof(bigint_word_t)))){
+            return 1;
+        }
+    }
+
+    if(!(m_int.wordv = malloc(hfal_hash_getHashsize(hash_desc) / 8))){
+        if(rand_in == NULL){
+            free(r_int.wordv);
+        }
+        return 1;
+    }
+    hfal_hash_mem(hash_desc, m_int.wordv, m, m_len_b);
+
+    do{
+        if(rand_in == NULL){
+            size_t i;
+            do{
+                i = ctx->curve->p->length_W * sizeof(bigint_word_t) - 1;
+                r_int.length_W = ctx->curve->p->length_W;
+                do{
+                    ((uint8_t*)r_int.wordv)[i] = prng_get_byte();
+                }while(i--);
+                bigint_adjust(&r_int);
+            }while(bigint_cmp_u(&r_int, ctx->curve->p) >= 0);
+        }
+    }while((r = ecdsa_sign_bigint(s, &m_int, ctx, &r_int)) == 2 && (rand_in == NULL));
+
+    return r;
+}