release/src/router/nettle/ecc-modq.c

   1 /* ecc-modq.c */
   2
   3 /* nettle, low-level cryptographics library
   4  *
   5  * Copyright (C) 2013 Niels Möller
   6  *
   7  * The nettle library is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU Lesser General Public License as published by
   9  * the Free Software Foundation; either version 2.1 of the License, or (at your
  10  * option) any later version.
  11  *
  12  * The nettle library is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  14  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  15  * License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public License
  18  * along with the nettle library; see the file COPYING.LIB.  If not, write to
  19  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  20  * MA 02111-1301, USA.
  21  */
  22
  23 /* Development of Nettle's ECC support was funded by the .SE Internet Fund. */
  24
  25 #if HAVE_CONFIG_H
  26 # include "config.h"
  27 #endif
  28
  29 #include <assert.h>
  30
  31 #include "ecc-internal.h"
  32
  33 /* Arithmetic mod q, the group order. */
  34
  35 void
  36 ecc_modq_add (const struct ecc_curve *ecc, mp_limb_t *rp,
  37               const mp_limb_t *ap, const mp_limb_t *bp)
  38 {
  39   mp_limb_t cy;
  40   cy = mpn_add_n (rp, ap, bp, ecc->size);
  41   cy = cnd_add_n (cy, rp, ecc->Bmodq, ecc->size);
  42   cy = cnd_add_n (cy, rp, ecc->Bmodq, ecc->size);
  43   assert (cy == 0);
  44 }
  45
  46 void
  47 ecc_modq_mul (const struct ecc_curve *ecc, mp_limb_t *rp,
  48               const mp_limb_t *ap, const mp_limb_t *bp)
  49 {
  50   mpn_mul_n (rp, ap, bp, ecc->size);
  51   ecc->modq (ecc, rp);
  52 }
  53
  54 void
  55 ecc_modq_inv (const struct ecc_curve *ecc, mp_limb_t *rp, mp_limb_t *ap,
  56               mp_limb_t *scratch)
  57 {
  58   sec_modinv (rp, ap, ecc->size, ecc->q, ecc->qp1h, ecc->bit_size, scratch);
  59 }