testfi.c

来自「这是一个C的源代码」· C语言 代码 · 共 61 行

#include "pbc.h"
#include "pbc_fp.h"
#include "pbc_fieldquadratic.h"

int main(void)
{
    field_t fp, fp2;
    mpz_t prime;
    element_t a, b, c;

    mpz_init(prime);
    mpz_set_ui(prime, 83); // 83 is 3 mod 4

    mpz_setbit(prime, 256);
    do {
	mpz_nextprime(prime, prime);
    } while (mpz_fdiv_ui(prime, 4) != 3);

    field_init_fp(fp, prime);
    field_init_fi(fp2, fp);
    element_init(a, fp2);
    element_init(b, fp2);
    element_init(c, fp2);

    element_printf("field: %Z^2\n", prime);

    element_random(a);
    element_random(b);
    element_printf("a = %B, b = %B\n", a, b);

    element_add(c, a, b);
    element_printf("a + b = %B\n", c);

    element_mul(c, a, b);
    element_printf("a * b = %B\n", c);

    for (;;) {
	element_random(a);
	element_printf("new a = %B\n", a);

	if (element_is_sqr(a)) break;
	printf(" is not a square\n");
    }
    element_sqrt(c, a);
    element_printf("sqrt(a) = %B\n", c);
    element_mul(c, c, c);
    element_printf("sqrt(a) * sqrt(a) = %B\n", c);
    element_invert(c, a);
    element_printf("1/a = %B\n", c);
    element_mul(c, c, a);
    element_printf("1/a * a = %B\n", c);

    element_clear(a);
    element_clear(b);
    element_clear(c);
    field_clear(fp);
    field_clear(fp2);
    mpz_clear(prime);
    return 0;
}