pqc/external/flint-2.4.3/ulong_extras/test/t-sqrtmodn.c

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2014-05-18 22:03:37 +00:00
/*=============================================================================
This file is part of FLINT.
FLINT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FLINT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with FLINT; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2011 Sebastian Pancratz
******************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <gmp.h>
#include "flint.h"
#include "ulong_extras.h"
int main(void)
{
int i, result;
FLINT_TEST_INIT(state);
flint_printf("sqrtmodn....");
fflush(stdout);
for (i = 0; i < 1000 * flint_test_multiplier(); i++) /* Test random squares mod n */
{
mp_limb_t a, b, n, ninv;
slong num, i;
mp_bitcnt_t bits;
mp_limb_t * sqrt;
int btest;
n_factor_t fac;
bits = n_randint(state, 18) + 2;
n = n_randtest_bits(state, bits);
if (n == 0) n = 1;
b = n_randtest(state) % n;
n_factor_init(&fac);
n_factor(&fac, n, 0);
ninv = n_preinvert_limb(n);
a = n_mulmod2_preinv(b, b, n, ninv);
num = n_sqrtmodn(&sqrt, a, &fac);
btest = 0;
for (i = 0; i < num; i++)
{
if (a != n_mulmod2_preinv(sqrt[i], sqrt[i], n, ninv))
break;
if (sqrt[i] == b)
btest = 1;
}
result = btest & (i == num);
if (!result)
{
flint_printf("FAIL:\n");
flint_printf("n = %wu\n", n);
flint_printf("a = %wu\n", a);
flint_printf("b = %wu\n", b);
flint_printf("num = %wd\n", num);
if (!btest)
flint_printf("Square root not found.\n");
if (i != num)
flint_printf("%wu not a square root of %wu mod %wu\n", sqrt[i], a, n);
abort();
}
flint_free(sqrt);
}
for (i = 0; i < 500 * flint_test_multiplier(); i++) /* test random nonsquares */
{
mp_limb_t a, b, n, ninv;
mp_bitcnt_t bits;
mp_limb_t * sqrt;
n_factor_t fac;
bits = n_randint(state, 18) + 2;
n = n_randtest_bits(state, bits);
if (n == 2) n++;
n_factor_init(&fac);
n_factor(&fac, n, 0);
ninv = n_preinvert_limb(n);
a = n_randtest(state) % n;
while (n_sqrtmodn(&sqrt, a, &fac))
{
if (n_mulmod2_preinv(sqrt[0], sqrt[0], n, ninv) != a)
{
flint_printf("FAIL:\n");
flint_printf("%wu^2 is not %wu mod %wu\n", sqrt[0], a, n);
abort();
}
flint_free(sqrt);
a = n_randtest(state) % n;
}
for (b = 0; b < n; b++)
{
if (n_mulmod2_preinv(b, b, n, ninv) == a)
break;
}
result = (b == n);
if (!result)
{
flint_printf("FAIL:\n");
flint_printf("n = %wu\n", n);
flint_printf("a = %wu\n", a);
flint_printf("b = %wu\n", b);
abort();
}
flint_free(sqrt);
}
FLINT_TEST_CLEANUP(state);
flint_printf("PASS\n");
return 0;
}