jdk/src/share/native/sun/security/ec/impl/ec2_mont.c
author vinnie
Mon, 21 Sep 2009 23:01:42 +0100
changeset 3863 8e0f58b1c072
child 5506 202f599c92aa
permissions -rw-r--r--
6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms Reviewed-by: wetmore
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/* *********************************************************************
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 *
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 * Sun elects to have this file available under and governed by the
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 * Mozilla Public License Version 1.1 ("MPL") (see
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 * http://www.mozilla.org/MPL/ for full license text). For the avoidance
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 * of doubt and subject to the following, Sun also elects to allow
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 * licensees to use this file under the MPL, the GNU General Public
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 * License version 2 only or the Lesser General Public License version
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 * 2.1 only. Any references to the "GNU General Public License version 2
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 * or later" or "GPL" in the following shall be construed to mean the
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 * GNU General Public License version 2 only. Any references to the "GNU
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 * Lesser General Public License version 2.1 or later" or "LGPL" in the
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 * following shall be construed to mean the GNU Lesser General Public
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 * License version 2.1 only. However, the following notice accompanied
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 * the original version of this file:
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 *
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 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
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 *
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 * The contents of this file are subject to the Mozilla Public License Version
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 * 1.1 (the "License"); you may not use this file except in compliance with
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 * the License. You may obtain a copy of the License at
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 * http://www.mozilla.org/MPL/
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 *
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 * Software distributed under the License is distributed on an "AS IS" basis,
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 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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 * for the specific language governing rights and limitations under the
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 * License.
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 *
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 * The Original Code is the elliptic curve math library for binary polynomial field curves.
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 *
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 * The Initial Developer of the Original Code is
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 * Sun Microsystems, Inc.
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 * Portions created by the Initial Developer are Copyright (C) 2003
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 * the Initial Developer. All Rights Reserved.
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 *
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 * Contributor(s):
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 *   Sheueling Chang-Shantz <sheueling.chang@sun.com>,
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 *   Stephen Fung <fungstep@hotmail.com>, and
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 *   Douglas Stebila <douglas@stebila.ca>, Sun Microsystems Laboratories.
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 *
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 * Alternatively, the contents of this file may be used under the terms of
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 * either the GNU General Public License Version 2 or later (the "GPL"), or
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 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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 * in which case the provisions of the GPL or the LGPL are applicable instead
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 * of those above. If you wish to allow use of your version of this file only
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 * under the terms of either the GPL or the LGPL, and not to allow others to
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 * use your version of this file under the terms of the MPL, indicate your
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 * decision by deleting the provisions above and replace them with the notice
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 * and other provisions required by the GPL or the LGPL. If you do not delete
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 * the provisions above, a recipient may use your version of this file under
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 * the terms of any one of the MPL, the GPL or the LGPL.
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 *
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 *********************************************************************** */
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/*
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 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
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 * Use is subject to license terms.
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 */
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#pragma ident   "%Z%%M% %I%     %E% SMI"
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#include "ec2.h"
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#include "mplogic.h"
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#include "mp_gf2m.h"
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#ifndef _KERNEL
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#include <stdlib.h>
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#endif
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/* Compute the x-coordinate x/z for the point 2*(x/z) in Montgomery
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 * projective coordinates. Uses algorithm Mdouble in appendix of Lopez, J.
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 * and Dahab, R.  "Fast multiplication on elliptic curves over GF(2^m)
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 * without precomputation". modified to not require precomputation of
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 * c=b^{2^{m-1}}. */
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static mp_err
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gf2m_Mdouble(mp_int *x, mp_int *z, const ECGroup *group, int kmflag)
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{
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        mp_err res = MP_OKAY;
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        mp_int t1;
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        MP_DIGITS(&t1) = 0;
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        MP_CHECKOK(mp_init(&t1, kmflag));
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        MP_CHECKOK(group->meth->field_sqr(x, x, group->meth));
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        MP_CHECKOK(group->meth->field_sqr(z, &t1, group->meth));
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        MP_CHECKOK(group->meth->field_mul(x, &t1, z, group->meth));
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        MP_CHECKOK(group->meth->field_sqr(x, x, group->meth));
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        MP_CHECKOK(group->meth->field_sqr(&t1, &t1, group->meth));
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        MP_CHECKOK(group->meth->
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                           field_mul(&group->curveb, &t1, &t1, group->meth));
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        MP_CHECKOK(group->meth->field_add(x, &t1, x, group->meth));
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  CLEANUP:
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        mp_clear(&t1);
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        return res;
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}
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/* Compute the x-coordinate x1/z1 for the point (x1/z1)+(x2/x2) in
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 * Montgomery projective coordinates. Uses algorithm Madd in appendix of
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 * Lopex, J. and Dahab, R.  "Fast multiplication on elliptic curves over
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 * GF(2^m) without precomputation". */
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static mp_err
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gf2m_Madd(const mp_int *x, mp_int *x1, mp_int *z1, mp_int *x2, mp_int *z2,
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                  const ECGroup *group, int kmflag)
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{
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        mp_err res = MP_OKAY;
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        mp_int t1, t2;
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        MP_DIGITS(&t1) = 0;
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        MP_DIGITS(&t2) = 0;
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        MP_CHECKOK(mp_init(&t1, kmflag));
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        MP_CHECKOK(mp_init(&t2, kmflag));
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        MP_CHECKOK(mp_copy(x, &t1));
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        MP_CHECKOK(group->meth->field_mul(x1, z2, x1, group->meth));
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        MP_CHECKOK(group->meth->field_mul(z1, x2, z1, group->meth));
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        MP_CHECKOK(group->meth->field_mul(x1, z1, &t2, group->meth));
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        MP_CHECKOK(group->meth->field_add(z1, x1, z1, group->meth));
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        MP_CHECKOK(group->meth->field_sqr(z1, z1, group->meth));
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        MP_CHECKOK(group->meth->field_mul(z1, &t1, x1, group->meth));
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        MP_CHECKOK(group->meth->field_add(x1, &t2, x1, group->meth));
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parents:
diff changeset
   120
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vinnie
parents:
diff changeset
   121
  CLEANUP:
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   122
        mp_clear(&t1);
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diff changeset
   123
        mp_clear(&t2);
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vinnie
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diff changeset
   124
        return res;
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vinnie
parents:
diff changeset
   125
}
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
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diff changeset
   126
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   127
/* Compute the x, y affine coordinates from the point (x1, z1) (x2, z2)
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   128
 * using Montgomery point multiplication algorithm Mxy() in appendix of
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diff changeset
   129
 * Lopex, J. and Dahab, R.  "Fast multiplication on elliptic curves over
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   130
 * GF(2^m) without precomputation". Returns: 0 on error 1 if return value
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parents:
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   131
 * should be the point at infinity 2 otherwise */
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   132
static int
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gf2m_Mxy(const mp_int *x, const mp_int *y, mp_int *x1, mp_int *z1,
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   134
                 mp_int *x2, mp_int *z2, const ECGroup *group)
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{
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        mp_err res = MP_OKAY;
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   137
        int ret = 0;
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   138
        mp_int t3, t4, t5;
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diff changeset
   139
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   140
        MP_DIGITS(&t3) = 0;
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   141
        MP_DIGITS(&t4) = 0;
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   142
        MP_DIGITS(&t5) = 0;
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diff changeset
   143
        MP_CHECKOK(mp_init(&t3, FLAG(x2)));
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   144
        MP_CHECKOK(mp_init(&t4, FLAG(x2)));
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diff changeset
   145
        MP_CHECKOK(mp_init(&t5, FLAG(x2)));
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parents:
diff changeset
   146
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   147
        if (mp_cmp_z(z1) == 0) {
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   148
                mp_zero(x2);
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diff changeset
   149
                mp_zero(z2);
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   150
                ret = 1;
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parents:
diff changeset
   151
                goto CLEANUP;
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parents:
diff changeset
   152
        }
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diff changeset
   153
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   154
        if (mp_cmp_z(z2) == 0) {
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   155
                MP_CHECKOK(mp_copy(x, x2));
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   156
                MP_CHECKOK(group->meth->field_add(x, y, z2, group->meth));
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   157
                ret = 2;
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diff changeset
   158
                goto CLEANUP;
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parents:
diff changeset
   159
        }
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diff changeset
   160
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diff changeset
   161
        MP_CHECKOK(mp_set_int(&t5, 1));
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diff changeset
   162
        if (group->meth->field_enc) {
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diff changeset
   163
                MP_CHECKOK(group->meth->field_enc(&t5, &t5, group->meth));
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diff changeset
   164
        }
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parents:
diff changeset
   165
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   166
        MP_CHECKOK(group->meth->field_mul(z1, z2, &t3, group->meth));
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parents:
diff changeset
   167
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diff changeset
   168
        MP_CHECKOK(group->meth->field_mul(z1, x, z1, group->meth));
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diff changeset
   169
        MP_CHECKOK(group->meth->field_add(z1, x1, z1, group->meth));
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diff changeset
   170
        MP_CHECKOK(group->meth->field_mul(z2, x, z2, group->meth));
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diff changeset
   171
        MP_CHECKOK(group->meth->field_mul(z2, x1, x1, group->meth));
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diff changeset
   172
        MP_CHECKOK(group->meth->field_add(z2, x2, z2, group->meth));
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parents:
diff changeset
   173
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diff changeset
   174
        MP_CHECKOK(group->meth->field_mul(z2, z1, z2, group->meth));
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diff changeset
   175
        MP_CHECKOK(group->meth->field_sqr(x, &t4, group->meth));
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diff changeset
   176
        MP_CHECKOK(group->meth->field_add(&t4, y, &t4, group->meth));
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diff changeset
   177
        MP_CHECKOK(group->meth->field_mul(&t4, &t3, &t4, group->meth));
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diff changeset
   178
        MP_CHECKOK(group->meth->field_add(&t4, z2, &t4, group->meth));
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parents:
diff changeset
   179
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diff changeset
   180
        MP_CHECKOK(group->meth->field_mul(&t3, x, &t3, group->meth));
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diff changeset
   181
        MP_CHECKOK(group->meth->field_div(&t5, &t3, &t3, group->meth));
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diff changeset
   182
        MP_CHECKOK(group->meth->field_mul(&t3, &t4, &t4, group->meth));
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
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parents:
diff changeset
   183
        MP_CHECKOK(group->meth->field_mul(x1, &t3, x2, group->meth));
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
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parents:
diff changeset
   184
        MP_CHECKOK(group->meth->field_add(x2, x, z2, group->meth));
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   185
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   186
        MP_CHECKOK(group->meth->field_mul(z2, &t4, z2, group->meth));
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   187
        MP_CHECKOK(group->meth->field_add(z2, y, z2, group->meth));
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   188
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   189
        ret = 2;
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vinnie
parents:
diff changeset
   190
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   191
  CLEANUP:
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vinnie
parents:
diff changeset
   192
        mp_clear(&t3);
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   193
        mp_clear(&t4);
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   194
        mp_clear(&t5);
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   195
        if (res == MP_OKAY) {
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   196
                return ret;
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   197
        } else {
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   198
                return 0;
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   199
        }
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   200
}
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   201
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   202
/* Computes R = nP based on algorithm 2P of Lopex, J. and Dahab, R.  "Fast
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   203
 * multiplication on elliptic curves over GF(2^m) without
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   204
 * precomputation". Elliptic curve points P and R can be identical. Uses
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   205
 * Montgomery projective coordinates. */
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   206
mp_err
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vinnie
parents:
diff changeset
   207
ec_GF2m_pt_mul_mont(const mp_int *n, const mp_int *px, const mp_int *py,
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diff changeset
   208
                                        mp_int *rx, mp_int *ry, const ECGroup *group)
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vinnie
parents:
diff changeset
   209
{
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diff changeset
   210
        mp_err res = MP_OKAY;
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vinnie
parents:
diff changeset
   211
        mp_int x1, x2, z1, z2;
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vinnie
parents:
diff changeset
   212
        int i, j;
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parents:
diff changeset
   213
        mp_digit top_bit, mask;
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vinnie
parents:
diff changeset
   214
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vinnie
parents:
diff changeset
   215
        MP_DIGITS(&x1) = 0;
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   216
        MP_DIGITS(&x2) = 0;
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   217
        MP_DIGITS(&z1) = 0;
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   218
        MP_DIGITS(&z2) = 0;
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   219
        MP_CHECKOK(mp_init(&x1, FLAG(n)));
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   220
        MP_CHECKOK(mp_init(&x2, FLAG(n)));
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   221
        MP_CHECKOK(mp_init(&z1, FLAG(n)));
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   222
        MP_CHECKOK(mp_init(&z2, FLAG(n)));
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   223
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   224
        /* if result should be point at infinity */
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   225
        if ((mp_cmp_z(n) == 0) || (ec_GF2m_pt_is_inf_aff(px, py) == MP_YES)) {
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   226
                MP_CHECKOK(ec_GF2m_pt_set_inf_aff(rx, ry));
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   227
                goto CLEANUP;
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   228
        }
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
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parents:
diff changeset
   229
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
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diff changeset
   230
        MP_CHECKOK(mp_copy(px, &x1));   /* x1 = px */
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   231
        MP_CHECKOK(mp_set_int(&z1, 1)); /* z1 = 1 */
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   232
        MP_CHECKOK(group->meth->field_sqr(&x1, &z2, group->meth));      /* z2 =
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   233
                                                                                                                                 * x1^2 =
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   234
                                                                                                                                 * px^2 */
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   235
        MP_CHECKOK(group->meth->field_sqr(&z2, &x2, group->meth));
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   236
        MP_CHECKOK(group->meth->field_add(&x2, &group->curveb, &x2, group->meth));      /* x2
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   237
                                                                                                                                                                 * =
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   238
                                                                                                                                                                 * px^4
8e0f58b1c072 6884175: CR cleanup for 6840752: Provide out-of-the-box support for ECC algorithms
vinnie
parents:
diff changeset
   239
                                                                                                                                                                 * +
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                                                                                                                                                                 * b
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                                                                                                                                                                 */
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        /* find top-most bit and go one past it */
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        i = MP_USED(n) - 1;
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        j = MP_DIGIT_BIT - 1;
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        top_bit = 1;
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        top_bit <<= MP_DIGIT_BIT - 1;
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        mask = top_bit;
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        while (!(MP_DIGITS(n)[i] & mask)) {
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                mask >>= 1;
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                j--;
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        }
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        mask >>= 1;
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        j--;
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        /* if top most bit was at word break, go to next word */
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        if (!mask) {
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                i--;
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                j = MP_DIGIT_BIT - 1;
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                mask = top_bit;
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        }
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        for (; i >= 0; i--) {
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                for (; j >= 0; j--) {
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                        if (MP_DIGITS(n)[i] & mask) {
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                                MP_CHECKOK(gf2m_Madd(px, &x1, &z1, &x2, &z2, group, FLAG(n)));
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                                MP_CHECKOK(gf2m_Mdouble(&x2, &z2, group, FLAG(n)));
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                        } else {
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                                MP_CHECKOK(gf2m_Madd(px, &x2, &z2, &x1, &z1, group, FLAG(n)));
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                                MP_CHECKOK(gf2m_Mdouble(&x1, &z1, group, FLAG(n)));
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                        }
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                        mask >>= 1;
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                }
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                j = MP_DIGIT_BIT - 1;
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                mask = top_bit;
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        }
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        /* convert out of "projective" coordinates */
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        i = gf2m_Mxy(px, py, &x1, &z1, &x2, &z2, group);
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        if (i == 0) {
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                res = MP_BADARG;
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                goto CLEANUP;
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        } else if (i == 1) {
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                MP_CHECKOK(ec_GF2m_pt_set_inf_aff(rx, ry));
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        } else {
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                MP_CHECKOK(mp_copy(&x2, rx));
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                MP_CHECKOK(mp_copy(&z2, ry));
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        }
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  CLEANUP:
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        mp_clear(&x1);
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        mp_clear(&x2);
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        mp_clear(&z1);
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        mp_clear(&z2);
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        return res;
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   296
}