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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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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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* 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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* The Original Code is the elliptic curve math library for binary polynomial field curves.
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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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* 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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* 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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* ***** END LICENSE BLOCK ***** */
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#include "mp_gf2m-priv.h"
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/* Fast reduction for polynomials over a 233-bit curve. Assumes reduction
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* polynomial with terms {233, 74, 0}. */
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ec_GF2m_233_mod(const mp_int *a, mp_int *r, const GFMethod *meth)
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MP_CHECKOK(mp_copy(a, r));
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#ifdef ECL_SIXTY_FOUR_BIT
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MP_CHECKOK(s_mp_pad(r, 8));
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/* u[7] only has 18 significant bits */
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u[4] ^= (z << 33) ^ (z >> 41);
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u[3] ^= (z << 33) ^ (z >> 41);
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u[2] ^= (z << 33) ^ (z >> 41);
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u[1] ^= (z << 33) ^ (z >> 41);
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z = u[3] >> 41; /* z only has 23 significant bits */
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/* clear bits above 233 */
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u[7] = u[6] = u[5] = u[4] = 0;
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if (MP_USED(r) < 15) {
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MP_CHECKOK(s_mp_pad(r, 15));
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/* u[14] only has 18 significant bits */
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z = u[7] >> 9; /* z only has 23 significant bits */
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/* clear bits above 233 */
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u[14] = u[13] = u[12] = u[11] = u[10] = u[9] = u[8] = 0;
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/* Fast squaring for polynomials over a 233-bit curve. Assumes reduction
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* polynomial with terms {233, 74, 0}. */
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ec_GF2m_233_sqr(const mp_int *a, mp_int *r, const GFMethod *meth)
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mp_err res = MP_OKAY;
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#ifdef ECL_SIXTY_FOUR_BIT
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if (MP_USED(a) < 4) {
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return mp_bsqrmod(a, meth->irr_arr, r);
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if (MP_USED(r) < 8) {
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MP_CHECKOK(s_mp_pad(r, 8));
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if (MP_USED(a) < 8) {
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return mp_bsqrmod(a, meth->irr_arr, r);
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if (MP_USED(r) < 15) {
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MP_CHECKOK(s_mp_pad(r, 15));
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#ifdef ECL_THIRTY_TWO_BIT
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u[14] = gf2m_SQR0(v[7]);
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u[13] = gf2m_SQR1(v[6]);
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u[12] = gf2m_SQR0(v[6]);
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u[11] = gf2m_SQR1(v[5]);
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u[10] = gf2m_SQR0(v[5]);
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u[9] = gf2m_SQR1(v[4]);
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u[8] = gf2m_SQR0(v[4]);
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u[7] = gf2m_SQR1(v[3]);
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u[6] = gf2m_SQR0(v[3]);
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u[5] = gf2m_SQR1(v[2]);
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u[4] = gf2m_SQR0(v[2]);
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u[3] = gf2m_SQR1(v[1]);
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u[2] = gf2m_SQR0(v[1]);
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u[1] = gf2m_SQR1(v[0]);
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u[0] = gf2m_SQR0(v[0]);
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return ec_GF2m_233_mod(r, r, meth);
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/* Fast multiplication for polynomials over a 233-bit curve. Assumes
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* reduction polynomial with terms {233, 74, 0}. */
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ec_GF2m_233_mul(const mp_int *a, const mp_int *b, mp_int *r,
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const GFMethod *meth)
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mp_err res = MP_OKAY;
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mp_digit a3 = 0, a2 = 0, a1 = 0, a0, b3 = 0, b2 = 0, b1 = 0, b0;
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#ifdef ECL_THIRTY_TWO_BIT
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mp_digit a7 = 0, a6 = 0, a5 = 0, a4 = 0, b7 = 0, b6 = 0, b5 = 0, b4 =
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return ec_GF2m_233_sqr(a, r, meth);
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switch (MP_USED(a)) {
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#ifdef ECL_THIRTY_TWO_BIT
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switch (MP_USED(b)) {
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#ifdef ECL_THIRTY_TWO_BIT
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#ifdef ECL_SIXTY_FOUR_BIT
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MP_CHECKOK(s_mp_pad(r, 8));
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s_bmul_4x4(MP_DIGITS(r), a3, a2, a1, a0, b3, b2, b1, b0);
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MP_CHECKOK(s_mp_pad(r, 16));
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s_bmul_4x4(MP_DIGITS(r) + 8, a7, a6, a5, a4, b7, b6, b5, b4);
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s_bmul_4x4(MP_DIGITS(r), a3, a2, a1, a0, b3, b2, b1, b0);
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s_bmul_4x4(rm, a7 ^ a3, a6 ^ a2, a5 ^ a1, a4 ^ a0, b7 ^ b3,
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b6 ^ b2, b5 ^ b1, b4 ^ b0);
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rm[7] ^= MP_DIGIT(r, 7) ^ MP_DIGIT(r, 15);
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rm[6] ^= MP_DIGIT(r, 6) ^ MP_DIGIT(r, 14);
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rm[5] ^= MP_DIGIT(r, 5) ^ MP_DIGIT(r, 13);
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rm[4] ^= MP_DIGIT(r, 4) ^ MP_DIGIT(r, 12);
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rm[3] ^= MP_DIGIT(r, 3) ^ MP_DIGIT(r, 11);
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rm[2] ^= MP_DIGIT(r, 2) ^ MP_DIGIT(r, 10);
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rm[1] ^= MP_DIGIT(r, 1) ^ MP_DIGIT(r, 9);
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rm[0] ^= MP_DIGIT(r, 0) ^ MP_DIGIT(r, 8);
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MP_DIGIT(r, 11) ^= rm[7];
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MP_DIGIT(r, 10) ^= rm[6];
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MP_DIGIT(r, 9) ^= rm[5];
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MP_DIGIT(r, 8) ^= rm[4];
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MP_DIGIT(r, 7) ^= rm[3];
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MP_DIGIT(r, 6) ^= rm[2];
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MP_DIGIT(r, 5) ^= rm[1];
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MP_DIGIT(r, 4) ^= rm[0];
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return ec_GF2m_233_mod(r, r, meth);
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/* Wire in fast field arithmetic for 233-bit curves. */
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ec_group_set_gf2m233(ECGroup *group, ECCurveName name)
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group->meth->field_mod = &ec_GF2m_233_mod;
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group->meth->field_mul = &ec_GF2m_233_mul;
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group->meth->field_sqr = &ec_GF2m_233_sqr;