/security/nss/lib/freebl/ecl/ecp_fp160.c
http://github.com/zpao/v8monkey · C · 179 lines · 90 code · 26 blank · 63 comment · 8 complexity · 73e0c2d38d11d0a40e2bed52d22bd035 MD5 · raw file
- /*
- * ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- * http://www.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is the elliptic curve math library for prime field curves using floating point operations.
- *
- * 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):
- * Stephen Fung <fungstep@hotmail.com>, Sun Microsystems Laboratories
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either the GNU General Public License Version 2 or later (the "GPL"), or
- * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK ***** */
- #include "ecp_fp.h"
- #include <stdlib.h>
- #define ECFP_BSIZE 160
- #define ECFP_NUMDOUBLES 7
- #include "ecp_fpinc.c"
- /* Performs a single step of reduction, just on the uppermost float
- * (assumes already tidied), and then retidies. Note, this does not
- * guarantee that the result will be less than p, but truncates the number
- * of bits. */
- void
- ecfp160_singleReduce(double *d, const EC_group_fp * group)
- {
- double q;
- ECFP_ASSERT(group->doubleBitSize == 24);
- ECFP_ASSERT(group->primeBitSize == 160);
- ECFP_ASSERT(ECFP_NUMDOUBLES == 7);
- q = d[ECFP_NUMDOUBLES - 1] - ecfp_beta_160;
- q += group->bitSize_alpha;
- q -= group->bitSize_alpha;
- d[ECFP_NUMDOUBLES - 1] -= q;
- d[0] += q * ecfp_twom160;
- d[1] += q * ecfp_twom129;
- ecfp_positiveTidy(d, group);
- /* Assertions for the highest order term */
- ECFP_ASSERT(d[ECFP_NUMDOUBLES - 1] / ecfp_exp[ECFP_NUMDOUBLES - 1] ==
- (unsigned long long) (d[ECFP_NUMDOUBLES - 1] /
- ecfp_exp[ECFP_NUMDOUBLES - 1]));
- ECFP_ASSERT(d[ECFP_NUMDOUBLES - 1] >= 0);
- }
- /* Performs imperfect reduction. This might leave some negative terms,
- * and one more reduction might be required for the result to be between 0
- * and p-1. x should not already be reduced, i.e. should have
- * 2*ECFP_NUMDOUBLES significant terms. x and r can be the same, but then
- * the upper parts of r are not zeroed */
- void
- ecfp160_reduce(double *r, double *x, const EC_group_fp * group)
- {
- double x7, x8, q;
- ECFP_ASSERT(group->doubleBitSize == 24);
- ECFP_ASSERT(group->primeBitSize == 160);
- ECFP_ASSERT(ECFP_NUMDOUBLES == 7);
- /* Tidy just the upper bits, the lower bits can wait. */
- ecfp_tidyUpper(x, group);
- /* Assume that this is already tidied so that we have enough extra
- * bits */
- x7 = x[7] + x[13] * ecfp_twom129; /* adds bits 15-39 */
- /* Tidy x7, or we won't have enough bits later to add it in */
- q = x7 + group->alpha[8];
- q -= group->alpha[8];
- x7 -= q; /* holds bits 0-24 */
- x8 = x[8] + q; /* holds bits 0-25 */
- r[6] = x[6] + x[13] * ecfp_twom160 + x[12] * ecfp_twom129; /* adds
- * bits
- * 8-39 */
- r[5] = x[5] + x[12] * ecfp_twom160 + x[11] * ecfp_twom129;
- r[4] = x[4] + x[11] * ecfp_twom160 + x[10] * ecfp_twom129;
- r[3] = x[3] + x[10] * ecfp_twom160 + x[9] * ecfp_twom129;
- r[2] = x[2] + x[9] * ecfp_twom160 + x8 * ecfp_twom129; /* adds bits
- * 8-40 */
- r[1] = x[1] + x8 * ecfp_twom160 + x7 * ecfp_twom129; /* adds bits
- * 8-39 */
- r[0] = x[0] + x7 * ecfp_twom160;
- /* Tidy up just r[ECFP_NUMDOUBLES-2] so that the number of reductions
- * is accurate plus or minus one. (Rather than tidy all to make it
- * totally accurate, which is more costly.) */
- q = r[ECFP_NUMDOUBLES - 2] + group->alpha[ECFP_NUMDOUBLES - 1];
- q -= group->alpha[ECFP_NUMDOUBLES - 1];
- r[ECFP_NUMDOUBLES - 2] -= q;
- r[ECFP_NUMDOUBLES - 1] += q;
- /* Tidy up the excess bits on r[ECFP_NUMDOUBLES-1] using reduction */
- /* Use ecfp_beta so we get a positive result */
- q = r[ECFP_NUMDOUBLES - 1] - ecfp_beta_160;
- q += group->bitSize_alpha;
- q -= group->bitSize_alpha;
- r[ECFP_NUMDOUBLES - 1] -= q;
- r[0] += q * ecfp_twom160;
- r[1] += q * ecfp_twom129;
- /* Tidy the result */
- ecfp_tidyShort(r, group);
- }
- /* Sets group to use optimized calculations in this file */
- mp_err
- ec_group_set_secp160r1_fp(ECGroup *group)
- {
- EC_group_fp *fpg = NULL;
- /* Allocate memory for floating point group data */
- fpg = (EC_group_fp *) malloc(sizeof(EC_group_fp));
- if (fpg == NULL) {
- return MP_MEM;
- }
- fpg->numDoubles = ECFP_NUMDOUBLES;
- fpg->primeBitSize = ECFP_BSIZE;
- fpg->orderBitSize = 161;
- fpg->doubleBitSize = 24;
- fpg->numInts = (ECFP_BSIZE + ECL_BITS - 1) / ECL_BITS;
- fpg->aIsM3 = 1;
- fpg->ecfp_singleReduce = &ecfp160_singleReduce;
- fpg->ecfp_reduce = &ecfp160_reduce;
- fpg->ecfp_tidy = &ecfp_tidy;
- fpg->pt_add_jac_aff = &ecfp160_pt_add_jac_aff;
- fpg->pt_add_jac = &ecfp160_pt_add_jac;
- fpg->pt_add_jm_chud = &ecfp160_pt_add_jm_chud;
- fpg->pt_add_chud = &ecfp160_pt_add_chud;
- fpg->pt_dbl_jac = &ecfp160_pt_dbl_jac;
- fpg->pt_dbl_jm = &ecfp160_pt_dbl_jm;
- fpg->pt_dbl_aff2chud = &ecfp160_pt_dbl_aff2chud;
- fpg->precompute_chud = &ecfp160_precompute_chud;
- fpg->precompute_jac = &ecfp160_precompute_jac;
- group->point_mul = &ec_GFp_point_mul_wNAF_fp;
- group->points_mul = &ec_pts_mul_basic;
- group->extra1 = fpg;
- group->extra_free = &ec_GFp_extra_free_fp;
- ec_set_fp_precision(fpg);
- fpg->bitSize_alpha = ECFP_TWO160 * fpg->alpha[0];
- return MP_OKAY;
- }