ecp_mont.c revision f9fbec18f5b458b560ecf45d3db8e8bd56bf6942
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings/*
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * ***** BEGIN LICENSE BLOCK *****
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * Version: MPL 1.1/GPL 2.0/LGPL 2.1
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings *
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * The contents of this file are subject to the Mozilla Public License Version
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * 1.1 (the "License"); you may not use this file except in compliance with
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * the License. You may obtain a copy of the License at
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * http://www.mozilla.org/MPL/
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings *
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * Software distributed under the License is distributed on an "AS IS" basis,
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * for the specific language governing rights and limitations under the
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * License.
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings *
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * The Original Code is the elliptic curve math library.
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings *
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * The Initial Developer of the Original Code is
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * Sun Microsystems, Inc.
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * Portions created by the Initial Developer are Copyright (C) 2003
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * the Initial Developer. All Rights Reserved.
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings *
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * Contributor(s):
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * Douglas Stebila <douglas@stebila.ca>, Sun Microsystems Laboratories
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings *
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * Alternatively, the contents of this file may be used under the terms of
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * either the GNU General Public License Version 2 or later (the "GPL"), or
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * in which case the provisions of the GPL or the LGPL are applicable instead
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * of those above. If you wish to allow use of your version of this file only
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * under the terms of either the GPL or the LGPL, and not to allow others to
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * use your version of this file under the terms of the MPL, indicate your
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * decision by deleting the provisions above and replace them with the notice
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * and other provisions required by the GPL or the LGPL. If you do not delete
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * the provisions above, a recipient may use your version of this file under
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * the terms of any one of the MPL, the GPL or the LGPL.
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings *
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * ***** END LICENSE BLOCK ***** */
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings/*
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * Use is subject to license terms.
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings *
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * Sun elects to use this software under the MPL license.
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings */
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings#pragma ident "%Z%%M% %I% %E% SMI"
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings/* Uses Montgomery reduction for field arithmetic. See mpi/mpmontg.c for
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * code implementation. */
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings#include "mpi.h"
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings#include "mplogic.h"
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings#include "mpi-priv.h"
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings#include "ecl-priv.h"
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings#include "ecp.h"
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings#ifndef _KERNEL
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings#include <stdlib.h>
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings#include <stdio.h>
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings#endif
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings/* Construct a generic GFMethod for arithmetic over prime fields with
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings * irreducible irr. */
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken StubbingsGFMethod *
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken StubbingsGFMethod_consGFp_mont(const mp_int *irr)
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings{
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings mp_err res = MP_OKAY;
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings int i;
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings GFMethod *meth = NULL;
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings mp_mont_modulus *mmm;
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings meth = GFMethod_consGFp(irr);
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings if (meth == NULL)
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings return NULL;
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings#ifdef _KERNEL
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings mmm = (mp_mont_modulus *) kmem_alloc(sizeof(mp_mont_modulus),
9ebd9a731316dfd624ce3bcc4ea6519d10899936Ken Stubbings FLAG(irr));
#else
mmm = (mp_mont_modulus *) malloc(sizeof(mp_mont_modulus));
#endif
if (mmm == NULL) {
res = MP_MEM;
goto CLEANUP;
}
meth->field_mul = &ec_GFp_mul_mont;
meth->field_sqr = &ec_GFp_sqr_mont;
meth->field_div = &ec_GFp_div_mont;
meth->field_enc = &ec_GFp_enc_mont;
meth->field_dec = &ec_GFp_dec_mont;
meth->extra1 = mmm;
meth->extra2 = NULL;
meth->extra_free = &ec_GFp_extra_free_mont;
mmm->N = meth->irr;
i = mpl_significant_bits(&meth->irr);
i += MP_DIGIT_BIT - 1;
mmm->b = i - i % MP_DIGIT_BIT;
mmm->n0prime = 0 - s_mp_invmod_radix(MP_DIGIT(&meth->irr, 0));
CLEANUP:
if (res != MP_OKAY) {
GFMethod_free(meth);
return NULL;
}
return meth;
}
/* Wrapper functions for generic prime field arithmetic. */
/* Field multiplication using Montgomery reduction. */
mp_err
ec_GFp_mul_mont(const mp_int *a, const mp_int *b, mp_int *r,
const GFMethod *meth)
{
mp_err res = MP_OKAY;
#ifdef MP_MONT_USE_MP_MUL
/* if MP_MONT_USE_MP_MUL is defined, then the function s_mp_mul_mont
* is not implemented and we have to use mp_mul and s_mp_redc directly
*/
MP_CHECKOK(mp_mul(a, b, r));
MP_CHECKOK(s_mp_redc(r, (mp_mont_modulus *) meth->extra1));
#else
mp_int s;
MP_DIGITS(&s) = 0;
/* s_mp_mul_mont doesn't allow source and destination to be the same */
if ((a == r) || (b == r)) {
MP_CHECKOK(mp_init(&s, FLAG(a)));
MP_CHECKOK(s_mp_mul_mont
(a, b, &s, (mp_mont_modulus *) meth->extra1));
MP_CHECKOK(mp_copy(&s, r));
mp_clear(&s);
} else {
return s_mp_mul_mont(a, b, r, (mp_mont_modulus *) meth->extra1);
}
#endif
CLEANUP:
return res;
}
/* Field squaring using Montgomery reduction. */
mp_err
ec_GFp_sqr_mont(const mp_int *a, mp_int *r, const GFMethod *meth)
{
return ec_GFp_mul_mont(a, a, r, meth);
}
/* Field division using Montgomery reduction. */
mp_err
ec_GFp_div_mont(const mp_int *a, const mp_int *b, mp_int *r,
const GFMethod *meth)
{
mp_err res = MP_OKAY;
/* if A=aZ represents a encoded in montgomery coordinates with Z and #
* and \ respectively represent multiplication and division in
* montgomery coordinates, then A\B = (a/b)Z = (A/B)Z and Binv =
* (1/b)Z = (1/B)(Z^2) where B # Binv = Z */
MP_CHECKOK(ec_GFp_div(a, b, r, meth));
MP_CHECKOK(ec_GFp_enc_mont(r, r, meth));
if (a == NULL) {
MP_CHECKOK(ec_GFp_enc_mont(r, r, meth));
}
CLEANUP:
return res;
}
/* Encode a field element in Montgomery form. See s_mp_to_mont in
* mpi/mpmontg.c */
mp_err
ec_GFp_enc_mont(const mp_int *a, mp_int *r, const GFMethod *meth)
{
mp_mont_modulus *mmm;
mp_err res = MP_OKAY;
mmm = (mp_mont_modulus *) meth->extra1;
MP_CHECKOK(mpl_lsh(a, r, mmm->b));
MP_CHECKOK(mp_mod(r, &mmm->N, r));
CLEANUP:
return res;
}
/* Decode a field element from Montgomery form. */
mp_err
ec_GFp_dec_mont(const mp_int *a, mp_int *r, const GFMethod *meth)
{
mp_err res = MP_OKAY;
if (a != r) {
MP_CHECKOK(mp_copy(a, r));
}
MP_CHECKOK(s_mp_redc(r, (mp_mont_modulus *) meth->extra1));
CLEANUP:
return res;
}
/* Free the memory allocated to the extra fields of Montgomery GFMethod
* object. */
void
ec_GFp_extra_free_mont(GFMethod *meth)
{
if (meth->extra1 != NULL) {
#ifdef _KERNEL
kmem_free(meth->extra1, sizeof(mp_mont_modulus));
#else
free(meth->extra1);
#endif
meth->extra1 = NULL;
}
}