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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mpi.h"
#include "mplogic.h"
#include "ecl.h"
#include "ecp.h"
#include "ecl-priv.h"
#include <sys/types.h>
#include <stdio.h>
#include <time.h>
#include <sys/time.h>
#include <sys/resource.h>
/* Returns 2^e as an integer. This is meant to be used for small powers of
* two. */
int ec_twoTo(int e);
/* Number of bits of scalar to test */
#define BITSIZE 160
/* Time k repetitions of operation op. */
#define M_TimeOperation(op, k) { \
double dStart, dNow, dUserTime; \
struct rusage ru; \
int i; \
getrusage(RUSAGE_SELF, &ru); \
dStart = (double)ru.ru_utime.tv_sec+(double)ru.ru_utime.tv_usec*0.000001; \
for (i = 0; i < k; i++) { \
{ op; } \
}; \
getrusage(RUSAGE_SELF, &ru); \
dNow = (double)ru.ru_utime.tv_sec+(double)ru.ru_utime.tv_usec*0.000001; \
dUserTime = dNow-dStart; \
if (dUserTime) printf(" %-45s\n k: %6i, t: %6.2f sec\n", #op, k, dUserTime); \
}
/* Tests wNAF computation. Non-adjacent-form is discussed in the paper: D.
* Hankerson, J. Hernandez and A. Menezes, "Software implementation of
* elliptic curve cryptography over binary fields", Proc. CHES 2000. */
mp_err
main(void)
{
signed char naf[BITSIZE + 1];
ECGroup *group = NULL;
mp_int k;
mp_int *scalar;
int i, count;
int res;
int w = 5;
char s[1000];
/* Get a 160 bit scalar to compute wNAF from */
group = ECGroup_fromName(ECCurve_SECG_PRIME_160R1);
scalar = &group->genx;
/* Compute wNAF representation of scalar */
ec_compute_wNAF(naf, BITSIZE, scalar, w);
/* Verify correctness of representation */
mp_init(&k); /* init k to 0 */
for (i = BITSIZE; i >= 0; i--) {
mp_add(&k, &k, &k);
/* digits in mp_???_d are unsigned */
if (naf[i] >= 0) {
mp_add_d(&k, naf[i], &k);
} else {
mp_sub_d(&k, -naf[i], &k);
}
}
if (mp_cmp(&k, scalar) != 0) {
printf("Error: incorrect NAF value.\n");
MP_CHECKOK(mp_toradix(&k, s, 16));
printf("NAF value %s\n", s);
MP_CHECKOK(mp_toradix(scalar, s, 16));
printf("original value %s\n", s);
goto CLEANUP;
}
/* Verify digits of representation are valid */
for (i = 0; i <= BITSIZE; i++) {
if (naf[i] % 2 == 0 && naf[i] != 0) {
printf("Error: Even non-zero digit found.\n");
goto CLEANUP;
}
if (naf[i] < -(ec_twoTo(w - 1)) || naf[i] >= ec_twoTo(w - 1)) {
printf("Error: Magnitude of naf digit too large.\n");
goto CLEANUP;
}
}
/* Verify sparsity of representation */
count = w - 1;
for (i = 0; i <= BITSIZE; i++) {
if (naf[i] != 0) {
if (count < w - 1) {
printf("Error: Sparsity failed.\n");
goto CLEANUP;
}
count = 0;
} else
count++;
}
/* Check timing */
M_TimeOperation(ec_compute_wNAF(naf, BITSIZE, scalar, w), 10000);
printf("Test passed.\n");
CLEANUP:
ECGroup_free(group);
return MP_OKAY;
}
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