release/src/router/nettle/ecc-a-to-j.c

   1 /* ecc-a-to-j.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 "ecc.h"
  30 #include "ecc-internal.h"
  31
  32 void
  33 ecc_a_to_j (const struct ecc_curve *ecc,
  34             int initial,
  35             mp_limb_t *r, const mp_limb_t *p)
  36 {
  37   if (ecc->use_redc && initial)
  38     {
  39       mpn_copyd (r + ecc->size, p, 2*ecc->size);
  40
  41       mpn_zero (r, ecc->size);
  42       ecc->modp (ecc, r);
  43
  44       mpn_zero (r + ecc->size, ecc->size);
  45       ecc->modp (ecc, r + ecc->size);
  46     }
  47   else if (r != p)
  48     mpn_copyi (r, p, 2*ecc->size);
  49
  50   mpn_copyi (r + 2*ecc->size, ecc->unit, ecc->size);
  51 }