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security/nss/lib/freebl/ecl/ecp_fp192.c@6474c204b198 (annotated)

security/nss/lib/freebl/ecl/ecp_fp192.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 192
michael@0 9 #define ECFP_NUMDOUBLES 8
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. */
michael@0 16 void
michael@0 17 ecfp192_singleReduce(double *d, const EC_group_fp * group)
michael@0 18 {
michael@0 19 double q;
michael@0 20
michael@0 21 ECFP_ASSERT(group->doubleBitSize == 24);
michael@0 22 ECFP_ASSERT(group->primeBitSize == 192);
michael@0 23 ECFP_ASSERT(group->numDoubles == 8);
michael@0 24
michael@0 25 q = d[ECFP_NUMDOUBLES - 1] - ecfp_beta_192;
michael@0 26 q += group->bitSize_alpha;
michael@0 27 q -= group->bitSize_alpha;
michael@0 28
michael@0 29 d[ECFP_NUMDOUBLES - 1] -= q;
michael@0 30 d[0] += q * ecfp_twom192;
michael@0 31 d[2] += q * ecfp_twom128;
michael@0 32 ecfp_positiveTidy(d, group);
michael@0 33 }
michael@0 34
michael@0 35 /*
michael@0 36 * Performs imperfect reduction. This might leave some negative terms,
michael@0 37 * and one more reduction might be required for the result to be between 0
michael@0 38 * and p-1. x should be be an array of at least 16, and r at least 8 x and
michael@0 39 * r can be the same, but then the upper parts of r are not zeroed */
michael@0 40 void
michael@0 41 ecfp_reduce_192(double *r, double *x, const EC_group_fp * group)
michael@0 42 {
michael@0 43 double x8, x9, x10, q;
michael@0 44
michael@0 45 ECFP_ASSERT(group->doubleBitSize == 24);
michael@0 46 ECFP_ASSERT(group->primeBitSize == 192);
michael@0 47 ECFP_ASSERT(group->numDoubles == 8);
michael@0 48
michael@0 49 /* Tidy just the upper portion, the lower part can wait */
michael@0 50 ecfp_tidyUpper(x, group);
michael@0 51
michael@0 52 x8 = x[8] + x[14] * ecfp_twom128; /* adds bits 16-40 */
michael@0 53 x9 = x[9] + x[15] * ecfp_twom128; /* adds bits 16-40 */
michael@0 54
michael@0 55 /* Tidy up, or we won't have enough bits later to add it in */
michael@0 56
michael@0 57 q = x8 + group->alpha[9];
michael@0 58 q -= group->alpha[9];
michael@0 59 x8 -= q;
michael@0 60 x9 += q;
michael@0 61
michael@0 62 q = x9 + group->alpha[10];
michael@0 63 q -= group->alpha[10];
michael@0 64 x9 -= q;
michael@0 65 x10 = x[10] + q;
michael@0 66
michael@0 67 r[7] = x[7] + x[15] * ecfp_twom192 + x[13] * ecfp_twom128; /* adds
michael@0 68 * bits
michael@0 69 * 0-40 */
michael@0 70 r[6] = x[6] + x[14] * ecfp_twom192 + x[12] * ecfp_twom128;
michael@0 71 r[5] = x[5] + x[13] * ecfp_twom192 + x[11] * ecfp_twom128;
michael@0 72 r[4] = x[4] + x[12] * ecfp_twom192 + x10 * ecfp_twom128;
michael@0 73 r[3] = x[3] + x[11] * ecfp_twom192 + x9 * ecfp_twom128; /* adds bits
michael@0 74 * 0-40 */
michael@0 75 r[2] = x[2] + x10 * ecfp_twom192 + x8 * ecfp_twom128;
michael@0 76 r[1] = x[1] + x9 * ecfp_twom192; /* adds bits 16-40 */
michael@0 77 r[0] = x[0] + x8 * ecfp_twom192;
michael@0 78
michael@0 79 /*
michael@0 80 * Tidy up just r[group->numDoubles-2] so that the number of
michael@0 81 * reductions is accurate plus or minus one. (Rather than tidy all to
michael@0 82 * make it totally accurate) */
michael@0 83 q = r[ECFP_NUMDOUBLES - 2] + group->alpha[ECFP_NUMDOUBLES - 1];
michael@0 84 q -= group->alpha[ECFP_NUMDOUBLES - 1];
michael@0 85 r[ECFP_NUMDOUBLES - 2] -= q;
michael@0 86 r[ECFP_NUMDOUBLES - 1] += q;
michael@0 87
michael@0 88 /* Tidy up the excess bits on r[group->numDoubles-1] using reduction */
michael@0 89 /* Use ecfp_beta so we get a positive res */
michael@0 90 q = r[ECFP_NUMDOUBLES - 1] - ecfp_beta_192;
michael@0 91 q += group->bitSize_alpha;
michael@0 92 q -= group->bitSize_alpha;
michael@0 93
michael@0 94 r[ECFP_NUMDOUBLES - 1] -= q;
michael@0 95 r[0] += q * ecfp_twom192;
michael@0 96 r[2] += q * ecfp_twom128;
michael@0 97
michael@0 98 /* Tidy the result */
michael@0 99 ecfp_tidyShort(r, group);
michael@0 100 }
michael@0 101
michael@0 102 /* Sets group to use optimized calculations in this file */
michael@0 103 mp_err
michael@0 104 ec_group_set_nistp192_fp(ECGroup *group)
michael@0 105 {
michael@0 106 EC_group_fp *fpg;
michael@0 107
michael@0 108 /* Allocate memory for floating point group data */
michael@0 109 fpg = (EC_group_fp *) malloc(sizeof(EC_group_fp));
michael@0 110 if (fpg == NULL) {
michael@0 111 return MP_MEM;
michael@0 112 }
michael@0 113
michael@0 114 fpg->numDoubles = ECFP_NUMDOUBLES;
michael@0 115 fpg->primeBitSize = ECFP_BSIZE;
michael@0 116 fpg->orderBitSize = 192;
michael@0 117 fpg->doubleBitSize = 24;
michael@0 118 fpg->numInts = (ECFP_BSIZE + ECL_BITS - 1) / ECL_BITS;
michael@0 119 fpg->aIsM3 = 1;
michael@0 120 fpg->ecfp_singleReduce = &ecfp192_singleReduce;
michael@0 121 fpg->ecfp_reduce = &ecfp_reduce_192;
michael@0 122 fpg->ecfp_tidy = &ecfp_tidy;
michael@0 123
michael@0 124 fpg->pt_add_jac_aff = &ecfp192_pt_add_jac_aff;
michael@0 125 fpg->pt_add_jac = &ecfp192_pt_add_jac;
michael@0 126 fpg->pt_add_jm_chud = &ecfp192_pt_add_jm_chud;
michael@0 127 fpg->pt_add_chud = &ecfp192_pt_add_chud;
michael@0 128 fpg->pt_dbl_jac = &ecfp192_pt_dbl_jac;
michael@0 129 fpg->pt_dbl_jm = &ecfp192_pt_dbl_jm;
michael@0 130 fpg->pt_dbl_aff2chud = &ecfp192_pt_dbl_aff2chud;
michael@0 131 fpg->precompute_chud = &ecfp192_precompute_chud;
michael@0 132 fpg->precompute_jac = &ecfp192_precompute_jac;
michael@0 133
michael@0 134 group->point_mul = &ec_GFp_point_mul_wNAF_fp;
michael@0 135 group->points_mul = &ec_pts_mul_basic;
michael@0 136 group->extra1 = fpg;
michael@0 137 group->extra_free = &ec_GFp_extra_free_fp;
michael@0 138
michael@0 139 ec_set_fp_precision(fpg);
michael@0 140 fpg->bitSize_alpha = ECFP_TWO192 * fpg->alpha[0];
michael@0 141
michael@0 142 return MP_OKAY;
michael@0 143 }

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