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lightning-sunbird  0.9+nobinonly
Functions
ecl_mult.c File Reference
#include "mpi.h"
#include "mplogic.h"
#include "ecl.h"
#include "ecl-priv.h"
#include <stdlib.h>

Go to the source code of this file.

Functions

mp_err ECPoint_mul (const ECGroup *group, const mp_int *k, const mp_int *px, const mp_int *py, mp_int *rx, mp_int *ry)
mp_err ec_pts_mul_basic (const mp_int *k1, const mp_int *k2, const mp_int *px, const mp_int *py, mp_int *rx, mp_int *ry, const ECGroup *group)
mp_err ec_pts_mul_simul_w2 (const mp_int *k1, const mp_int *k2, const mp_int *px, const mp_int *py, mp_int *rx, mp_int *ry, const ECGroup *group)
mp_err ECPoints_mul (const ECGroup *group, const mp_int *k1, const mp_int *k2, const mp_int *px, const mp_int *py, mp_int *rx, mp_int *ry)

Function Documentation

mp_err ec_pts_mul_basic ( const mp_int k1,
const mp_int k2,
const mp_int px,
const mp_int py,
mp_int rx,
mp_int ry,
const ECGroup *  group 
)

Definition at line 104 of file ecl_mult.c.

{
       mp_err res = MP_OKAY;
       mp_int sx, sy;

       ARGCHK(group != NULL, MP_BADARG);
       ARGCHK(!((k1 == NULL)
                      && ((k2 == NULL) || (px == NULL)
                             || (py == NULL))), MP_BADARG);

       /* if some arguments are not defined used ECPoint_mul */
       if (k1 == NULL) {
              return ECPoint_mul(group, k2, px, py, rx, ry);
       } else if ((k2 == NULL) || (px == NULL) || (py == NULL)) {
              return ECPoint_mul(group, k1, NULL, NULL, rx, ry);
       }

       MP_DIGITS(&sx) = 0;
       MP_DIGITS(&sy) = 0;
       MP_CHECKOK(mp_init(&sx));
       MP_CHECKOK(mp_init(&sy));

       MP_CHECKOK(ECPoint_mul(group, k1, NULL, NULL, &sx, &sy));
       MP_CHECKOK(ECPoint_mul(group, k2, px, py, rx, ry));

       if (group->meth->field_enc) {
              MP_CHECKOK(group->meth->field_enc(&sx, &sx, group->meth));
              MP_CHECKOK(group->meth->field_enc(&sy, &sy, group->meth));
              MP_CHECKOK(group->meth->field_enc(rx, rx, group->meth));
              MP_CHECKOK(group->meth->field_enc(ry, ry, group->meth));
       }

       MP_CHECKOK(group->point_add(&sx, &sy, rx, ry, rx, ry, group));

       if (group->meth->field_dec) {
              MP_CHECKOK(group->meth->field_dec(rx, rx, group->meth));
              MP_CHECKOK(group->meth->field_dec(ry, ry, group->meth));
       }

  CLEANUP:
       mp_clear(&sx);
       mp_clear(&sy);
       return res;
}

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mp_err ec_pts_mul_simul_w2 ( const mp_int k1,
const mp_int k2,
const mp_int px,
const mp_int py,
mp_int rx,
mp_int ry,
const ECGroup *  group 
)

Definition at line 159 of file ecl_mult.c.

{
       mp_err res = MP_OKAY;
       mp_int precomp[4][4][2];
       const mp_int *a, *b;
       int i, j;
       int ai, bi, d;

       ARGCHK(group != NULL, MP_BADARG);
       ARGCHK(!((k1 == NULL)
                      && ((k2 == NULL) || (px == NULL)
                             || (py == NULL))), MP_BADARG);

       /* if some arguments are not defined used ECPoint_mul */
       if (k1 == NULL) {
              return ECPoint_mul(group, k2, px, py, rx, ry);
       } else if ((k2 == NULL) || (px == NULL) || (py == NULL)) {
              return ECPoint_mul(group, k1, NULL, NULL, rx, ry);
       }

       /* initialize precomputation table */
       for (i = 0; i < 4; i++) {
              for (j = 0; j < 4; j++) {
                     MP_DIGITS(&precomp[i][j][0]) = 0;
                     MP_DIGITS(&precomp[i][j][1]) = 0;
              }
       }
       for (i = 0; i < 4; i++) {
              for (j = 0; j < 4; j++) {
                      MP_CHECKOK( mp_init_size(&precomp[i][j][0],
                                           ECL_MAX_FIELD_SIZE_DIGITS) );
                      MP_CHECKOK( mp_init_size(&precomp[i][j][1],
                                           ECL_MAX_FIELD_SIZE_DIGITS) );
              }
       }

       /* fill precomputation table */
       /* assign {k1, k2} = {a, b} such that len(a) >= len(b) */
       if (mpl_significant_bits(k1) < mpl_significant_bits(k2)) {
              a = k2;
              b = k1;
              if (group->meth->field_enc) {
                     MP_CHECKOK(group->meth->
                                      field_enc(px, &precomp[1][0][0], group->meth));
                     MP_CHECKOK(group->meth->
                                      field_enc(py, &precomp[1][0][1], group->meth));
              } else {
                     MP_CHECKOK(mp_copy(px, &precomp[1][0][0]));
                     MP_CHECKOK(mp_copy(py, &precomp[1][0][1]));
              }
              MP_CHECKOK(mp_copy(&group->genx, &precomp[0][1][0]));
              MP_CHECKOK(mp_copy(&group->geny, &precomp[0][1][1]));
       } else {
              a = k1;
              b = k2;
              MP_CHECKOK(mp_copy(&group->genx, &precomp[1][0][0]));
              MP_CHECKOK(mp_copy(&group->geny, &precomp[1][0][1]));
              if (group->meth->field_enc) {
                     MP_CHECKOK(group->meth->
                                      field_enc(px, &precomp[0][1][0], group->meth));
                     MP_CHECKOK(group->meth->
                                      field_enc(py, &precomp[0][1][1], group->meth));
              } else {
                     MP_CHECKOK(mp_copy(px, &precomp[0][1][0]));
                     MP_CHECKOK(mp_copy(py, &precomp[0][1][1]));
              }
       }
       /* precompute [*][0][*] */
       mp_zero(&precomp[0][0][0]);
       mp_zero(&precomp[0][0][1]);
       MP_CHECKOK(group->
                        point_dbl(&precomp[1][0][0], &precomp[1][0][1],
                                           &precomp[2][0][0], &precomp[2][0][1], group));
       MP_CHECKOK(group->
                        point_add(&precomp[1][0][0], &precomp[1][0][1],
                                           &precomp[2][0][0], &precomp[2][0][1],
                                           &precomp[3][0][0], &precomp[3][0][1], group));
       /* precompute [*][1][*] */
       for (i = 1; i < 4; i++) {
              MP_CHECKOK(group->
                               point_add(&precomp[0][1][0], &precomp[0][1][1],
                                                  &precomp[i][0][0], &precomp[i][0][1],
                                                  &precomp[i][1][0], &precomp[i][1][1], group));
       }
       /* precompute [*][2][*] */
       MP_CHECKOK(group->
                        point_dbl(&precomp[0][1][0], &precomp[0][1][1],
                                           &precomp[0][2][0], &precomp[0][2][1], group));
       for (i = 1; i < 4; i++) {
              MP_CHECKOK(group->
                               point_add(&precomp[0][2][0], &precomp[0][2][1],
                                                  &precomp[i][0][0], &precomp[i][0][1],
                                                  &precomp[i][2][0], &precomp[i][2][1], group));
       }
       /* precompute [*][3][*] */
       MP_CHECKOK(group->
                        point_add(&precomp[0][1][0], &precomp[0][1][1],
                                           &precomp[0][2][0], &precomp[0][2][1],
                                           &precomp[0][3][0], &precomp[0][3][1], group));
       for (i = 1; i < 4; i++) {
              MP_CHECKOK(group->
                               point_add(&precomp[0][3][0], &precomp[0][3][1],
                                                  &precomp[i][0][0], &precomp[i][0][1],
                                                  &precomp[i][3][0], &precomp[i][3][1], group));
       }

       d = (mpl_significant_bits(a) + 1) / 2;

       /* R = inf */
       mp_zero(rx);
       mp_zero(ry);

       for (i = d - 1; i >= 0; i--) {
              ai = MP_GET_BIT(a, 2 * i + 1);
              ai <<= 1;
              ai |= MP_GET_BIT(a, 2 * i);
              bi = MP_GET_BIT(b, 2 * i + 1);
              bi <<= 1;
              bi |= MP_GET_BIT(b, 2 * i);
              /* R = 2^2 * R */
              MP_CHECKOK(group->point_dbl(rx, ry, rx, ry, group));
              MP_CHECKOK(group->point_dbl(rx, ry, rx, ry, group));
              /* R = R + (ai * A + bi * B) */
              MP_CHECKOK(group->
                               point_add(rx, ry, &precomp[ai][bi][0],
                                                  &precomp[ai][bi][1], rx, ry, group));
       }

       if (group->meth->field_dec) {
              MP_CHECKOK(group->meth->field_dec(rx, rx, group->meth));
              MP_CHECKOK(group->meth->field_dec(ry, ry, group->meth));
       }

  CLEANUP:
       for (i = 0; i < 4; i++) {
              for (j = 0; j < 4; j++) {
                     mp_clear(&precomp[i][j][0]);
                     mp_clear(&precomp[i][j][1]);
              }
       }
       return res;
}

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mp_err ECPoint_mul ( const ECGroup *  group,
const mp_int k,
const mp_int px,
const mp_int py,
mp_int rx,
mp_int ry 
)

Definition at line 50 of file ecl_mult.c.

{
       mp_err res = MP_OKAY;
       mp_int kt;

       ARGCHK((k != NULL) && (group != NULL), MP_BADARG);
       MP_DIGITS(&kt) = 0;

       /* want scalar to be less than or equal to group order */
       if (mp_cmp(k, &group->order) > 0) {
              MP_CHECKOK(mp_init(&kt));
              MP_CHECKOK(mp_mod(k, &group->order, &kt));
       } else {
              MP_SIGN(&kt) = MP_ZPOS;
              MP_USED(&kt) = MP_USED(k);
              MP_ALLOC(&kt) = MP_ALLOC(k);
              MP_DIGITS(&kt) = MP_DIGITS(k);
       }

       if ((px == NULL) || (py == NULL)) {
              if (group->base_point_mul) {
                     MP_CHECKOK(group->base_point_mul(&kt, rx, ry, group));
              } else {
                     MP_CHECKOK(group->
                                      point_mul(&kt, &group->genx, &group->geny, rx, ry,
                                                         group));
              }
       } else {
              if (group->meth->field_enc) {
                     MP_CHECKOK(group->meth->field_enc(px, rx, group->meth));
                     MP_CHECKOK(group->meth->field_enc(py, ry, group->meth));
                     MP_CHECKOK(group->point_mul(&kt, rx, ry, rx, ry, group));
              } else {
                     MP_CHECKOK(group->point_mul(&kt, px, py, rx, ry, group));
              }
       }
       if (group->meth->field_dec) {
              MP_CHECKOK(group->meth->field_dec(rx, rx, group->meth));
              MP_CHECKOK(group->meth->field_dec(ry, ry, group->meth));
       }

  CLEANUP:
       if (MP_DIGITS(&kt) != MP_DIGITS(k)) {
              mp_clear(&kt);
       }
       return res;
}

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mp_err ECPoints_mul ( const ECGroup *  group,
const mp_int k1,
const mp_int k2,
const mp_int px,
const mp_int py,
mp_int rx,
mp_int ry 
)

Definition at line 309 of file ecl_mult.c.

{
       mp_err res = MP_OKAY;
       mp_int k1t, k2t;
       const mp_int *k1p, *k2p;

       MP_DIGITS(&k1t) = 0;
       MP_DIGITS(&k2t) = 0;

       ARGCHK(group != NULL, MP_BADARG);

       /* want scalar to be less than or equal to group order */
       if (k1 != NULL) {
              if (mp_cmp(k1, &group->order) >= 0) {
                     MP_CHECKOK(mp_init(&k1t));
                     MP_CHECKOK(mp_mod(k1, &group->order, &k1t));
                     k1p = &k1t;
              } else {
                     k1p = k1;
              }
       } else {
              k1p = k1;
       }
       if (k2 != NULL) {
              if (mp_cmp(k2, &group->order) >= 0) {
                     MP_CHECKOK(mp_init(&k2t));
                     MP_CHECKOK(mp_mod(k2, &group->order, &k2t));
                     k2p = &k2t;
              } else {
                     k2p = k2;
              }
       } else {
              k2p = k2;
       }

       /* if points_mul is defined, then use it */
       if (group->points_mul) {
              res = group->points_mul(k1p, k2p, px, py, rx, ry, group);
       } else {
              res = ec_pts_mul_simul_w2(k1p, k2p, px, py, rx, ry, group);
       }

  CLEANUP:
       mp_clear(&k1t);
       mp_clear(&k2t);
       return res;
}

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