crypto/ecc/ec2_163.c

f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers/*
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * ***** BEGIN LICENSE BLOCK *****
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * Version: MPL 1.1/GPL 2.0/LGPL 2.1
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers *
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * The contents of this file are subject to the Mozilla Public License Version
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * 1.1 (the "License"); you may not use this file except in compliance with
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * the License. You may obtain a copy of the License at
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * http://www.mozilla.org/MPL/
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers *
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * Software distributed under the License is distributed on an "AS IS" basis,
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * for the specific language governing rights and limitations under the
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * License.
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers *
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * The Original Code is the elliptic curve math library for binary polynomial field curves.
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers *
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * The Initial Developer of the Original Code is
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * Sun Microsystems, Inc.
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * Portions created by the Initial Developer are Copyright (C) 2003
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * the Initial Developer. All Rights Reserved.
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers *
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * Contributor(s):
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers *   Sheueling Chang-Shantz <sheueling.chang@sun.com>,
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers *   Stephen Fung <fungstep@hotmail.com>, and
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers *   Douglas Stebila <douglas@stebila.ca>, Sun Microsystems Laboratories.
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers *
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * Alternatively, the contents of this file may be used under the terms of
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * either the GNU General Public License Version 2 or later (the "GPL"), or
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * in which case the provisions of the GPL or the LGPL are applicable instead
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * of those above. If you wish to allow use of your version of this file only
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * under the terms of either the GPL or the LGPL, and not to allow others to
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * use your version of this file under the terms of the MPL, indicate your
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * decision by deleting the provisions above and replace them with the notice
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * and other provisions required by the GPL or the LGPL. If you do not delete
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * the provisions above, a recipient may use your version of this file under
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * the terms of any one of the MPL, the GPL or the LGPL.
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers *
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * ***** END LICENSE BLOCK ***** */
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers/*
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * Use is subject to license terms.
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers *
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * Sun elects to use this software under the MPL license.
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers */
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#pragma ident   "%Z%%M% %I% %E% SMI"
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#include "ec2.h"
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#include "mp_gf2m.h"
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#include "mp_gf2m-priv.h"
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#include "mpi.h"
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#include "mpi-priv.h"
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#ifndef _KERNEL
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#include <stdlib.h>
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#endif
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers/* Fast reduction for polynomials over a 163-bit curve. Assumes reduction
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * polynomial with terms {163, 7, 6, 3, 0}. */
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowersmp_err
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowersec_GF2m_163_mod(const mp_int *a, mp_int *r, const GFMethod *meth)
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers{
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    mp_err res = MP_OKAY;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    mp_digit *u, z;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    if (a != r) {
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        MP_CHECKOK(mp_copy(a, r));
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    }
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#ifdef ECL_SIXTY_FOUR_BIT
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    if (MP_USED(r) < 6) {
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        MP_CHECKOK(s_mp_pad(r, 6));
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    }
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u = MP_DIGITS(r);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    MP_USED(r) = 6;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    /* u[5] only has 6 significant bits */
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    z = u[5];
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[2] ^= (z << 36) ^ (z << 35) ^ (z << 32) ^ (z << 29);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    z = u[4];
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[2] ^= (z >> 28) ^ (z >> 29) ^ (z >> 32) ^ (z >> 35);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[1] ^= (z << 36) ^ (z << 35) ^ (z << 32) ^ (z << 29);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    z = u[3];
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[1] ^= (z >> 28) ^ (z >> 29) ^ (z >> 32) ^ (z >> 35);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[0] ^= (z << 36) ^ (z << 35) ^ (z << 32) ^ (z << 29);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    z = u[2] >> 35;             /* z only has 29 significant bits */
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[0] ^= (z << 7) ^ (z << 6) ^ (z << 3) ^ z;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    /* clear bits above 163 */
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[5] = u[4] = u[3] = 0;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[2] ^= z << 35;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#else
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    if (MP_USED(r) < 11) {
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        MP_CHECKOK(s_mp_pad(r, 11));
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    }
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u = MP_DIGITS(r);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    MP_USED(r) = 11;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    /* u[11] only has 6 significant bits */
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    z = u[10];
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[5] ^= (z << 4) ^ (z << 3) ^ z ^ (z >> 3);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[4] ^= (z << 29);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    z = u[9];
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[5] ^= (z >> 28) ^ (z >> 29);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[4] ^= (z << 4) ^ (z << 3) ^ z ^ (z >> 3);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[3] ^= (z << 29);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    z = u[8];
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[4] ^= (z >> 28) ^ (z >> 29);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[3] ^= (z << 4) ^ (z << 3) ^ z ^ (z >> 3);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[2] ^= (z << 29);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    z = u[7];
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[3] ^= (z >> 28) ^ (z >> 29);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[2] ^= (z << 4) ^ (z << 3) ^ z ^ (z >> 3);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[1] ^= (z << 29);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    z = u[6];
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[2] ^= (z >> 28) ^ (z >> 29);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[1] ^= (z << 4) ^ (z << 3) ^ z ^ (z >> 3);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[0] ^= (z << 29);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    z = u[5] >> 3;              /* z only has 29 significant bits */
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[1] ^= (z >> 25) ^ (z >> 26);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[0] ^= (z << 7) ^ (z << 6) ^ (z << 3) ^ z;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    /* clear bits above 163 */
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[11] = u[10] = u[9] = u[8] = u[7] = u[6] = 0;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[5] ^= z << 3;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#endif
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    s_mp_clamp(r);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers  CLEANUP:
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    return res;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers}
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers/* Fast squaring for polynomials over a 163-bit curve. Assumes reduction
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * polynomial with terms {163, 7, 6, 3, 0}. */
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowersmp_err
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowersec_GF2m_163_sqr(const mp_int *a, mp_int *r, const GFMethod *meth)
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers{
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    mp_err res = MP_OKAY;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    mp_digit *u, *v;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    v = MP_DIGITS(a);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#ifdef ECL_SIXTY_FOUR_BIT
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    if (MP_USED(a) < 3) {
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        return mp_bsqrmod(a, meth->irr_arr, r);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    }
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    if (MP_USED(r) < 6) {
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        MP_CHECKOK(s_mp_pad(r, 6));
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    }
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    MP_USED(r) = 6;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#else
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    if (MP_USED(a) < 6) {
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        return mp_bsqrmod(a, meth->irr_arr, r);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    }
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    if (MP_USED(r) < 12) {
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        MP_CHECKOK(s_mp_pad(r, 12));
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    }
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    MP_USED(r) = 12;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#endif
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u = MP_DIGITS(r);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#ifdef ECL_THIRTY_TWO_BIT
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[11] = gf2m_SQR1(v[5]);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[10] = gf2m_SQR0(v[5]);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[9] = gf2m_SQR1(v[4]);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[8] = gf2m_SQR0(v[4]);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[7] = gf2m_SQR1(v[3]);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[6] = gf2m_SQR0(v[3]);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#endif
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[5] = gf2m_SQR1(v[2]);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[4] = gf2m_SQR0(v[2]);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[3] = gf2m_SQR1(v[1]);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[2] = gf2m_SQR0(v[1]);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[1] = gf2m_SQR1(v[0]);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    u[0] = gf2m_SQR0(v[0]);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    return ec_GF2m_163_mod(r, r, meth);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers  CLEANUP:
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    return res;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers}
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers/* Fast multiplication for polynomials over a 163-bit curve. Assumes
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers * reduction polynomial with terms {163, 7, 6, 3, 0}. */
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowersmp_err
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowersec_GF2m_163_mul(const mp_int *a, const mp_int *b, mp_int *r,
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers                const GFMethod *meth)
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers{
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    mp_err res = MP_OKAY;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    mp_digit a2 = 0, a1 = 0, a0, b2 = 0, b1 = 0, b0;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#ifdef ECL_THIRTY_TWO_BIT
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    mp_digit a5 = 0, a4 = 0, a3 = 0, b5 = 0, b4 = 0, b3 = 0;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    mp_digit rm[6];
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#endif
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    if (a == b) {
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        return ec_GF2m_163_sqr(a, r, meth);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    } else {
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        switch (MP_USED(a)) {
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#ifdef ECL_THIRTY_TWO_BIT
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        case 6:
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers            a5 = MP_DIGIT(a, 5);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        case 5:
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers            a4 = MP_DIGIT(a, 4);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        case 4:
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers            a3 = MP_DIGIT(a, 3);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#endif
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        case 3:
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers            a2 = MP_DIGIT(a, 2);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        case 2:
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers            a1 = MP_DIGIT(a, 1);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        default:
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers            a0 = MP_DIGIT(a, 0);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        }
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        switch (MP_USED(b)) {
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#ifdef ECL_THIRTY_TWO_BIT
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        case 6:
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers            b5 = MP_DIGIT(b, 5);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        case 5:
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers            b4 = MP_DIGIT(b, 4);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        case 4:
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers            b3 = MP_DIGIT(b, 3);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#endif
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        case 3:
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers            b2 = MP_DIGIT(b, 2);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        case 2:
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers            b1 = MP_DIGIT(b, 1);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        default:
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers            b0 = MP_DIGIT(b, 0);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        }
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#ifdef ECL_SIXTY_FOUR_BIT
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        MP_CHECKOK(s_mp_pad(r, 6));
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        s_bmul_3x3(MP_DIGITS(r), a2, a1, a0, b2, b1, b0);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        MP_USED(r) = 6;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        s_mp_clamp(r);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#else
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        MP_CHECKOK(s_mp_pad(r, 12));
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        s_bmul_3x3(MP_DIGITS(r) + 6, a5, a4, a3, b5, b4, b3);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        s_bmul_3x3(MP_DIGITS(r), a2, a1, a0, b2, b1, b0);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        s_bmul_3x3(rm, a5 ^ a2, a4 ^ a1, a3 ^ a0, b5 ^ b2, b4 ^ b1,
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers                   b3 ^ b0);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        rm[5] ^= MP_DIGIT(r, 5) ^ MP_DIGIT(r, 11);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        rm[4] ^= MP_DIGIT(r, 4) ^ MP_DIGIT(r, 10);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        rm[3] ^= MP_DIGIT(r, 3) ^ MP_DIGIT(r, 9);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        rm[2] ^= MP_DIGIT(r, 2) ^ MP_DIGIT(r, 8);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        rm[1] ^= MP_DIGIT(r, 1) ^ MP_DIGIT(r, 7);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        rm[0] ^= MP_DIGIT(r, 0) ^ MP_DIGIT(r, 6);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        MP_DIGIT(r, 8) ^= rm[5];
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        MP_DIGIT(r, 7) ^= rm[4];
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        MP_DIGIT(r, 6) ^= rm[3];
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        MP_DIGIT(r, 5) ^= rm[2];
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        MP_DIGIT(r, 4) ^= rm[1];
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        MP_DIGIT(r, 3) ^= rm[0];
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        MP_USED(r) = 12;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        s_mp_clamp(r);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers#endif
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers        return ec_GF2m_163_mod(r, r, meth);
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    }
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers  CLEANUP:
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    return res;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers}
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers/* Wire in fast field arithmetic for 163-bit curves. */
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowersmp_err
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowersec_group_set_gf2m163(ECGroup *group, ECCurveName name)
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers{
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    group->meth->field_mod = &ec_GF2m_163_mod;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    group->meth->field_mul = &ec_GF2m_163_mul;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    group->meth->field_sqr = &ec_GF2m_163_sqr;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers    return MP_OKAY;
f9fbec18f5b458b560ecf45d3db8e8bd56bf6942mcpowers}