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security/nss/lib/freebl/ecl/ecp_fp192.c@b8a032363ba2 (annotated)

security/nss/lib/freebl/ecl/ecp_fp192.c

Thu, 22 Jan 2015 13:21:57 +0100

author

Michael Schloh von Bennewitz <michael@schloh.com>

date

Thu, 22 Jan 2015 13:21:57 +0100

branch

TOR_BUG_9701

changeset 15

b8a032363ba2

permissions

-rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

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	}