1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/security/nss/lib/freebl/ecl/ecp_fp160.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,145 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +#include "ecp_fp.h"
1.9 +#include <stdlib.h>
1.10 +
1.11 +#define ECFP_BSIZE 160
1.12 +#define ECFP_NUMDOUBLES 7
1.13 +
1.14 +#include "ecp_fpinc.c"
1.15 +
1.16 +/* Performs a single step of reduction, just on the uppermost float
1.17 + * (assumes already tidied), and then retidies. Note, this does not
1.18 + * guarantee that the result will be less than p, but truncates the number
1.19 + * of bits. */
1.20 +void
1.21 +ecfp160_singleReduce(double *d, const EC_group_fp * group)
1.22 +{
1.23 + double q;
1.24 +
1.25 + ECFP_ASSERT(group->doubleBitSize == 24);
1.26 + ECFP_ASSERT(group->primeBitSize == 160);
1.27 + ECFP_ASSERT(ECFP_NUMDOUBLES == 7);
1.28 +
1.29 + q = d[ECFP_NUMDOUBLES - 1] - ecfp_beta_160;
1.30 + q += group->bitSize_alpha;
1.31 + q -= group->bitSize_alpha;
1.32 +
1.33 + d[ECFP_NUMDOUBLES - 1] -= q;
1.34 + d[0] += q * ecfp_twom160;
1.35 + d[1] += q * ecfp_twom129;
1.36 + ecfp_positiveTidy(d, group);
1.37 +
1.38 + /* Assertions for the highest order term */
1.39 + ECFP_ASSERT(d[ECFP_NUMDOUBLES - 1] / ecfp_exp[ECFP_NUMDOUBLES - 1] ==
1.40 + (unsigned long long) (d[ECFP_NUMDOUBLES - 1] /
1.41 + ecfp_exp[ECFP_NUMDOUBLES - 1]));
1.42 + ECFP_ASSERT(d[ECFP_NUMDOUBLES - 1] >= 0);
1.43 +}
1.44 +
1.45 +/* Performs imperfect reduction. This might leave some negative terms,
1.46 + * and one more reduction might be required for the result to be between 0
1.47 + * and p-1. x should not already be reduced, i.e. should have
1.48 + * 2*ECFP_NUMDOUBLES significant terms. x and r can be the same, but then
1.49 + * the upper parts of r are not zeroed */
1.50 +void
1.51 +ecfp160_reduce(double *r, double *x, const EC_group_fp * group)
1.52 +{
1.53 +
1.54 + double x7, x8, q;
1.55 +
1.56 + ECFP_ASSERT(group->doubleBitSize == 24);
1.57 + ECFP_ASSERT(group->primeBitSize == 160);
1.58 + ECFP_ASSERT(ECFP_NUMDOUBLES == 7);
1.59 +
1.60 + /* Tidy just the upper bits, the lower bits can wait. */
1.61 + ecfp_tidyUpper(x, group);
1.62 +
1.63 + /* Assume that this is already tidied so that we have enough extra
1.64 + * bits */
1.65 + x7 = x[7] + x[13] * ecfp_twom129; /* adds bits 15-39 */
1.66 +
1.67 + /* Tidy x7, or we won't have enough bits later to add it in */
1.68 + q = x7 + group->alpha[8];
1.69 + q -= group->alpha[8];
1.70 + x7 -= q; /* holds bits 0-24 */
1.71 + x8 = x[8] + q; /* holds bits 0-25 */
1.72 +
1.73 + r[6] = x[6] + x[13] * ecfp_twom160 + x[12] * ecfp_twom129; /* adds
1.74 + * bits
1.75 + * 8-39 */
1.76 + r[5] = x[5] + x[12] * ecfp_twom160 + x[11] * ecfp_twom129;
1.77 + r[4] = x[4] + x[11] * ecfp_twom160 + x[10] * ecfp_twom129;
1.78 + r[3] = x[3] + x[10] * ecfp_twom160 + x[9] * ecfp_twom129;
1.79 + r[2] = x[2] + x[9] * ecfp_twom160 + x8 * ecfp_twom129; /* adds bits
1.80 + * 8-40 */
1.81 + r[1] = x[1] + x8 * ecfp_twom160 + x7 * ecfp_twom129; /* adds bits
1.82 + * 8-39 */
1.83 + r[0] = x[0] + x7 * ecfp_twom160;
1.84 +
1.85 + /* Tidy up just r[ECFP_NUMDOUBLES-2] so that the number of reductions
1.86 + * is accurate plus or minus one. (Rather than tidy all to make it
1.87 + * totally accurate, which is more costly.) */
1.88 + q = r[ECFP_NUMDOUBLES - 2] + group->alpha[ECFP_NUMDOUBLES - 1];
1.89 + q -= group->alpha[ECFP_NUMDOUBLES - 1];
1.90 + r[ECFP_NUMDOUBLES - 2] -= q;
1.91 + r[ECFP_NUMDOUBLES - 1] += q;
1.92 +
1.93 + /* Tidy up the excess bits on r[ECFP_NUMDOUBLES-1] using reduction */
1.94 + /* Use ecfp_beta so we get a positive result */
1.95 + q = r[ECFP_NUMDOUBLES - 1] - ecfp_beta_160;
1.96 + q += group->bitSize_alpha;
1.97 + q -= group->bitSize_alpha;
1.98 +
1.99 + r[ECFP_NUMDOUBLES - 1] -= q;
1.100 + r[0] += q * ecfp_twom160;
1.101 + r[1] += q * ecfp_twom129;
1.102 +
1.103 + /* Tidy the result */
1.104 + ecfp_tidyShort(r, group);
1.105 +}
1.106 +
1.107 +/* Sets group to use optimized calculations in this file */
1.108 +mp_err
1.109 +ec_group_set_secp160r1_fp(ECGroup *group)
1.110 +{
1.111 +
1.112 + EC_group_fp *fpg = NULL;
1.113 +
1.114 + /* Allocate memory for floating point group data */
1.115 + fpg = (EC_group_fp *) malloc(sizeof(EC_group_fp));
1.116 + if (fpg == NULL) {
1.117 + return MP_MEM;
1.118 + }
1.119 +
1.120 + fpg->numDoubles = ECFP_NUMDOUBLES;
1.121 + fpg->primeBitSize = ECFP_BSIZE;
1.122 + fpg->orderBitSize = 161;
1.123 + fpg->doubleBitSize = 24;
1.124 + fpg->numInts = (ECFP_BSIZE + ECL_BITS - 1) / ECL_BITS;
1.125 + fpg->aIsM3 = 1;
1.126 + fpg->ecfp_singleReduce = &ecfp160_singleReduce;
1.127 + fpg->ecfp_reduce = &ecfp160_reduce;
1.128 + fpg->ecfp_tidy = &ecfp_tidy;
1.129 +
1.130 + fpg->pt_add_jac_aff = &ecfp160_pt_add_jac_aff;
1.131 + fpg->pt_add_jac = &ecfp160_pt_add_jac;
1.132 + fpg->pt_add_jm_chud = &ecfp160_pt_add_jm_chud;
1.133 + fpg->pt_add_chud = &ecfp160_pt_add_chud;
1.134 + fpg->pt_dbl_jac = &ecfp160_pt_dbl_jac;
1.135 + fpg->pt_dbl_jm = &ecfp160_pt_dbl_jm;
1.136 + fpg->pt_dbl_aff2chud = &ecfp160_pt_dbl_aff2chud;
1.137 + fpg->precompute_chud = &ecfp160_precompute_chud;
1.138 + fpg->precompute_jac = &ecfp160_precompute_jac;
1.139 +
1.140 + group->point_mul = &ec_GFp_point_mul_wNAF_fp;
1.141 + group->points_mul = &ec_pts_mul_basic;
1.142 + group->extra1 = fpg;
1.143 + group->extra_free = &ec_GFp_extra_free_fp;
1.144 +
1.145 + ec_set_fp_precision(fpg);
1.146 + fpg->bitSize_alpha = ECFP_TWO160 * fpg->alpha[0];
1.147 + return MP_OKAY;
1.148 +}
