/*
* Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved.
* Use is subject to license terms.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/* *********************************************************************
*
* The Original Code is the elliptic curve math library for binary polynomial field curves.
*
* The Initial Developer of the Original Code is
* Sun Microsystems, Inc.
* Portions created by the Initial Developer are Copyright (C) 2003
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Sheueling Chang-Shantz <sheueling.chang@sun.com>,
* Stephen Fung <fungstep@hotmail.com>, and
* Douglas Stebila <douglas@stebila.ca>, Sun Microsystems Laboratories.
*
*********************************************************************** */
#include "ec2.h"
#include "mp_gf2m.h"
#include "mp_gf2m-priv.h"
#include "mpi.h"
#include "mpi-priv.h"
#ifndef _KERNEL
#include <stdlib.h>
#endif
/* Fast reduction for polynomials over a 193-bit curve. Assumes reduction
* polynomial with terms {193, 15, 0}. */
mp_err
ec_GF2m_193_mod(const mp_int *a, mp_int *r, const GFMethod *meth)
{
mp_err res = MP_OKAY;
mp_digit *u, z;
if (a != r) {
MP_CHECKOK(mp_copy(a, r));
}
#ifdef ECL_SIXTY_FOUR_BIT
if (MP_USED(r) < 7) {
MP_CHECKOK(s_mp_pad(r, 7));
}
u = MP_DIGITS(r);
MP_USED(r) = 7;
/* u[6] only has 2 significant bits */
z = u[6];
u[3] ^= (z << 14) ^ (z >> 1);
u[2] ^= (z << 63);
z = u[5];
u[3] ^= (z >> 50);
u[2] ^= (z << 14) ^ (z >> 1);
u[1] ^= (z << 63);
z = u[4];
u[2] ^= (z >> 50);
u[1] ^= (z << 14) ^ (z >> 1);
u[0] ^= (z << 63);
z = u[3] >> 1; /* z only has 63 significant bits */
u[1] ^= (z >> 49);
u[0] ^= (z << 15) ^ z;
/* clear bits above 193 */
u[6] = u[5] = u[4] = 0;
u[3] ^= z << 1;
#else
if (MP_USED(r) < 13) {
MP_CHECKOK(s_mp_pad(r, 13));
}
u = MP_DIGITS(r);
MP_USED(r) = 13;
/* u[12] only has 2 significant bits */
z = u[12];
u[6] ^= (z << 14) ^ (z >> 1);
u[5] ^= (z << 31);
z = u[11];
u[6] ^= (z >> 18);
u[5] ^= (z << 14) ^ (z >> 1);
u[4] ^= (z << 31);
z = u[10];
u[5] ^= (z >> 18);
u[4] ^= (z << 14) ^ (z >> 1);
u[3] ^= (z << 31);
z = u[9];
u[4] ^= (z >> 18);
u[3] ^= (z << 14) ^ (z >> 1);
u[2] ^= (z << 31);
z = u[8];
u[3] ^= (z >> 18);
u[2] ^= (z << 14) ^ (z >> 1);
u[1] ^= (z << 31);
z = u[7];
u[2] ^= (z >> 18);
u[1] ^= (z << 14) ^ (z >> 1);
u[0] ^= (z << 31);
z = u[6] >> 1; /* z only has 31 significant bits */
u[1] ^= (z >> 17);
u[0] ^= (z << 15) ^ z;
/* clear bits above 193 */
u[12] = u[11] = u[10] = u[9] = u[8] = u[7] = 0;
u[6] ^= z << 1;
#endif
s_mp_clamp(r);
CLEANUP:
return res;
}
/* Fast squaring for polynomials over a 193-bit curve. Assumes reduction
* polynomial with terms {193, 15, 0}. */
mp_err
ec_GF2m_193_sqr(const mp_int *a, mp_int *r, const GFMethod *meth)
{
mp_err res = MP_OKAY;
mp_digit *u, *v;
v = MP_DIGITS(a);
#ifdef ECL_SIXTY_FOUR_BIT
if (MP_USED(a) < 4) {
return mp_bsqrmod(a, meth->irr_arr, r);
}
if (MP_USED(r) < 7) {
MP_CHECKOK(s_mp_pad(r, 7));
}
MP_USED(r) = 7;
#else
if (MP_USED(a) < 7) {
return mp_bsqrmod(a, meth->irr_arr, r);
}
if (MP_USED(r) < 13) {
MP_CHECKOK(s_mp_pad(r, 13));
}
MP_USED(r) = 13;
#endif
u = MP_DIGITS(r);
#ifdef ECL_THIRTY_TWO_BIT
u[12] = gf2m_SQR0(v[6]);
u[11] = gf2m_SQR1(v[5]);
u[10] = gf2m_SQR0(v[5]);
u[9] = gf2m_SQR1(v[4]);
u[8] = gf2m_SQR0(v[4]);
u[7] = gf2m_SQR1(v[3]);
#endif
u[6] = gf2m_SQR0(v[3]);
u[5] = gf2m_SQR1(v[2]);
u[4] = gf2m_SQR0(v[2]);
u[3] = gf2m_SQR1(v[1]);
u[2] = gf2m_SQR0(v[1]);
u[1] = gf2m_SQR1(v[0]);
u[0] = gf2m_SQR0(v[0]);
return ec_GF2m_193_mod(r, r, meth);
CLEANUP:
return res;
}
/* Fast multiplication for polynomials over a 193-bit curve. Assumes
* reduction polynomial with terms {193, 15, 0}. */
mp_err
ec_GF2m_193_mul(const mp_int *a, const mp_int *b, mp_int *r,
const GFMethod *meth)
{
mp_err res = MP_OKAY;
mp_digit a3 = 0, a2 = 0, a1 = 0, a0, b3 = 0, b2 = 0, b1 = 0, b0;
#ifdef ECL_THIRTY_TWO_BIT
mp_digit a6 = 0, a5 = 0, a4 = 0, b6 = 0, b5 = 0, b4 = 0;
mp_digit rm[8];
#endif
if (a == b) {
return ec_GF2m_193_sqr(a, r, meth);
} else {
switch (MP_USED(a)) {
#ifdef ECL_THIRTY_TWO_BIT
case 7:
a6 = MP_DIGIT(a, 6);
case 6:
a5 = MP_DIGIT(a, 5);
case 5:
a4 = MP_DIGIT(a, 4);
#endif
case 4:
a3 = MP_DIGIT(a, 3);
case 3:
a2 = MP_DIGIT(a, 2);
case 2:
a1 = MP_DIGIT(a, 1);
default:
a0 = MP_DIGIT(a, 0);
}
switch (MP_USED(b)) {
#ifdef ECL_THIRTY_TWO_BIT
case 7:
b6 = MP_DIGIT(b, 6);
case 6:
b5 = MP_DIGIT(b, 5);
case 5:
b4 = MP_DIGIT(b, 4);
#endif
case 4:
b3 = MP_DIGIT(b, 3);
case 3:
b2 = MP_DIGIT(b, 2);
case 2:
b1 = MP_DIGIT(b, 1);
default:
b0 = MP_DIGIT(b, 0);
}
#ifdef ECL_SIXTY_FOUR_BIT
MP_CHECKOK(s_mp_pad(r, 8));
s_bmul_4x4(MP_DIGITS(r), a3, a2, a1, a0, b3, b2, b1, b0);
MP_USED(r) = 8;
s_mp_clamp(r);
#else
MP_CHECKOK(s_mp_pad(r, 14));
s_bmul_3x3(MP_DIGITS(r) + 8, a6, a5, a4, b6, b5, b4);
s_bmul_4x4(MP_DIGITS(r), a3, a2, a1, a0, b3, b2, b1, b0);
s_bmul_4x4(rm, a3, a6 ^ a2, a5 ^ a1, a4 ^ a0, b3, b6 ^ b2, b5 ^ b1,
b4 ^ b0);
rm[7] ^= MP_DIGIT(r, 7);
rm[6] ^= MP_DIGIT(r, 6);
rm[5] ^= MP_DIGIT(r, 5) ^ MP_DIGIT(r, 13);
rm[4] ^= MP_DIGIT(r, 4) ^ MP_DIGIT(r, 12);
rm[3] ^= MP_DIGIT(r, 3) ^ MP_DIGIT(r, 11);
rm[2] ^= MP_DIGIT(r, 2) ^ MP_DIGIT(r, 10);
rm[1] ^= MP_DIGIT(r, 1) ^ MP_DIGIT(r, 9);
rm[0] ^= MP_DIGIT(r, 0) ^ MP_DIGIT(r, 8);
MP_DIGIT(r, 11) ^= rm[7];
MP_DIGIT(r, 10) ^= rm[6];
MP_DIGIT(r, 9) ^= rm[5];
MP_DIGIT(r, 8) ^= rm[4];
MP_DIGIT(r, 7) ^= rm[3];
MP_DIGIT(r, 6) ^= rm[2];
MP_DIGIT(r, 5) ^= rm[1];
MP_DIGIT(r, 4) ^= rm[0];
MP_USED(r) = 14;
s_mp_clamp(r);
#endif
return ec_GF2m_193_mod(r, r, meth);
}
CLEANUP:
return res;
}
/* Wire in fast field arithmetic for 193-bit curves. */
mp_err
ec_group_set_gf2m193(ECGroup *group, ECCurveName name)
{
group->meth->field_mod = &ec_GF2m_193_mod;
group->meth->field_mul = &ec_GF2m_193_mul;
group->meth->field_sqr = &ec_GF2m_193_sqr;
return MP_OKAY;
}