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security/nss/lib/freebl/ecl/ecp_fp160.c@6474c204b198 (annotated)

security/nss/lib/freebl/ecl/ecp_fp160.c

Wed, 31 Dec 2014 06:09:35 +0100

author
Michael Schloh von Bennewitz <michael@schloh.com>
date
Wed, 31 Dec 2014 06:09:35 +0100
changeset 0
6474c204b198
permissions
-rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

michael@0 1 /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0 2 * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0 4
michael@0 5 #include "ecp_fp.h"
michael@0 6 #include <stdlib.h>
michael@0 7
michael@0 8 #define ECFP_BSIZE 160
michael@0 9 #define ECFP_NUMDOUBLES 7
michael@0 10
michael@0 11 #include "ecp_fpinc.c"
michael@0 12
michael@0 13 /* Performs a single step of reduction, just on the uppermost float
michael@0 14 * (assumes already tidied), and then retidies. Note, this does not
michael@0 15 * guarantee that the result will be less than p, but truncates the number
michael@0 16 * of bits. */
michael@0 17 void
michael@0 18 ecfp160_singleReduce(double *d, const EC_group_fp * group)
michael@0 19 {
michael@0 20 double q;
michael@0 21
michael@0 22 ECFP_ASSERT(group->doubleBitSize == 24);
michael@0 23 ECFP_ASSERT(group->primeBitSize == 160);
michael@0 24 ECFP_ASSERT(ECFP_NUMDOUBLES == 7);
michael@0 25
michael@0 26 q = d[ECFP_NUMDOUBLES - 1] - ecfp_beta_160;
michael@0 27 q += group->bitSize_alpha;
michael@0 28 q -= group->bitSize_alpha;
michael@0 29
michael@0 30 d[ECFP_NUMDOUBLES - 1] -= q;
michael@0 31 d[0] += q * ecfp_twom160;
michael@0 32 d[1] += q * ecfp_twom129;
michael@0 33 ecfp_positiveTidy(d, group);
michael@0 34
michael@0 35 /* Assertions for the highest order term */
michael@0 36 ECFP_ASSERT(d[ECFP_NUMDOUBLES - 1] / ecfp_exp[ECFP_NUMDOUBLES - 1] ==
michael@0 37 (unsigned long long) (d[ECFP_NUMDOUBLES - 1] /
michael@0 38 ecfp_exp[ECFP_NUMDOUBLES - 1]));
michael@0 39 ECFP_ASSERT(d[ECFP_NUMDOUBLES - 1] >= 0);
michael@0 40 }
michael@0 41
michael@0 42 /* Performs imperfect reduction. This might leave some negative terms,
michael@0 43 * and one more reduction might be required for the result to be between 0
michael@0 44 * and p-1. x should not already be reduced, i.e. should have
michael@0 45 * 2*ECFP_NUMDOUBLES significant terms. x and r can be the same, but then
michael@0 46 * the upper parts of r are not zeroed */
michael@0 47 void
michael@0 48 ecfp160_reduce(double *r, double *x, const EC_group_fp * group)
michael@0 49 {
michael@0 50
michael@0 51 double x7, x8, q;
michael@0 52
michael@0 53 ECFP_ASSERT(group->doubleBitSize == 24);
michael@0 54 ECFP_ASSERT(group->primeBitSize == 160);
michael@0 55 ECFP_ASSERT(ECFP_NUMDOUBLES == 7);
michael@0 56
michael@0 57 /* Tidy just the upper bits, the lower bits can wait. */
michael@0 58 ecfp_tidyUpper(x, group);
michael@0 59
michael@0 60 /* Assume that this is already tidied so that we have enough extra
michael@0 61 * bits */
michael@0 62 x7 = x[7] + x[13] * ecfp_twom129; /* adds bits 15-39 */
michael@0 63
michael@0 64 /* Tidy x7, or we won't have enough bits later to add it in */
michael@0 65 q = x7 + group->alpha[8];
michael@0 66 q -= group->alpha[8];
michael@0 67 x7 -= q; /* holds bits 0-24 */
michael@0 68 x8 = x[8] + q; /* holds bits 0-25 */
michael@0 69
michael@0 70 r[6] = x[6] + x[13] * ecfp_twom160 + x[12] * ecfp_twom129; /* adds
michael@0 71 * bits
michael@0 72 * 8-39 */
michael@0 73 r[5] = x[5] + x[12] * ecfp_twom160 + x[11] * ecfp_twom129;
michael@0 74 r[4] = x[4] + x[11] * ecfp_twom160 + x[10] * ecfp_twom129;
michael@0 75 r[3] = x[3] + x[10] * ecfp_twom160 + x[9] * ecfp_twom129;
michael@0 76 r[2] = x[2] + x[9] * ecfp_twom160 + x8 * ecfp_twom129; /* adds bits
michael@0 77 * 8-40 */
michael@0 78 r[1] = x[1] + x8 * ecfp_twom160 + x7 * ecfp_twom129; /* adds bits
michael@0 79 * 8-39 */
michael@0 80 r[0] = x[0] + x7 * ecfp_twom160;
michael@0 81
michael@0 82 /* Tidy up just r[ECFP_NUMDOUBLES-2] so that the number of reductions
michael@0 83 * is accurate plus or minus one. (Rather than tidy all to make it
michael@0 84 * totally accurate, which is more costly.) */
michael@0 85 q = r[ECFP_NUMDOUBLES - 2] + group->alpha[ECFP_NUMDOUBLES - 1];
michael@0 86 q -= group->alpha[ECFP_NUMDOUBLES - 1];
michael@0 87 r[ECFP_NUMDOUBLES - 2] -= q;
michael@0 88 r[ECFP_NUMDOUBLES - 1] += q;
michael@0 89
michael@0 90 /* Tidy up the excess bits on r[ECFP_NUMDOUBLES-1] using reduction */
michael@0 91 /* Use ecfp_beta so we get a positive result */
michael@0 92 q = r[ECFP_NUMDOUBLES - 1] - ecfp_beta_160;
michael@0 93 q += group->bitSize_alpha;
michael@0 94 q -= group->bitSize_alpha;
michael@0 95
michael@0 96 r[ECFP_NUMDOUBLES - 1] -= q;
michael@0 97 r[0] += q * ecfp_twom160;
michael@0 98 r[1] += q * ecfp_twom129;
michael@0 99
michael@0 100 /* Tidy the result */
michael@0 101 ecfp_tidyShort(r, group);
michael@0 102 }
michael@0 103
michael@0 104 /* Sets group to use optimized calculations in this file */
michael@0 105 mp_err
michael@0 106 ec_group_set_secp160r1_fp(ECGroup *group)
michael@0 107 {
michael@0 108
michael@0 109 EC_group_fp *fpg = NULL;
michael@0 110
michael@0 111 /* Allocate memory for floating point group data */
michael@0 112 fpg = (EC_group_fp *) malloc(sizeof(EC_group_fp));
michael@0 113 if (fpg == NULL) {
michael@0 114 return MP_MEM;
michael@0 115 }
michael@0 116
michael@0 117 fpg->numDoubles = ECFP_NUMDOUBLES;
michael@0 118 fpg->primeBitSize = ECFP_BSIZE;
michael@0 119 fpg->orderBitSize = 161;
michael@0 120 fpg->doubleBitSize = 24;
michael@0 121 fpg->numInts = (ECFP_BSIZE + ECL_BITS - 1) / ECL_BITS;
michael@0 122 fpg->aIsM3 = 1;
michael@0 123 fpg->ecfp_singleReduce = &ecfp160_singleReduce;
michael@0 124 fpg->ecfp_reduce = &ecfp160_reduce;
michael@0 125 fpg->ecfp_tidy = &ecfp_tidy;
michael@0 126
michael@0 127 fpg->pt_add_jac_aff = &ecfp160_pt_add_jac_aff;
michael@0 128 fpg->pt_add_jac = &ecfp160_pt_add_jac;
michael@0 129 fpg->pt_add_jm_chud = &ecfp160_pt_add_jm_chud;
michael@0 130 fpg->pt_add_chud = &ecfp160_pt_add_chud;
michael@0 131 fpg->pt_dbl_jac = &ecfp160_pt_dbl_jac;
michael@0 132 fpg->pt_dbl_jm = &ecfp160_pt_dbl_jm;
michael@0 133 fpg->pt_dbl_aff2chud = &ecfp160_pt_dbl_aff2chud;
michael@0 134 fpg->precompute_chud = &ecfp160_precompute_chud;
michael@0 135 fpg->precompute_jac = &ecfp160_precompute_jac;
michael@0 136
michael@0 137 group->point_mul = &ec_GFp_point_mul_wNAF_fp;
michael@0 138 group->points_mul = &ec_pts_mul_basic;
michael@0 139 group->extra1 = fpg;
michael@0 140 group->extra_free = &ec_GFp_extra_free_fp;
michael@0 141
michael@0 142 ec_set_fp_precision(fpg);
michael@0 143 fpg->bitSize_alpha = ECFP_TWO160 * fpg->alpha[0];
michael@0 144 return MP_OKAY;
michael@0 145 }

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