-rw-r--r-- 1923 high-ctidh-20210504/fp.h
#ifndef FP_H
#define FP_H
#include "uintbig.h"
#include "fp_namespace.h"
/* fp is in the Montgomery domain, so interpreting that
as an integer should never make sense.
enable compiler warnings when mixing up uintbig and fp. */
typedef struct fp {
uintbig x;
} fp;
extern const fp fp_0;
extern const fp fp_1;
extern const fp fp_2;
void fp_cswap(fp *x, fp *y, long long c); /* c is 0 or 1 */
void fp_cmov(fp *x, const fp *y, long long c); /* c is 0 or 1 */
void fp_add2(fp *x, fp const *y);
void fp_sub2(fp *x, fp const *y);
void fp_mul2(fp *x, fp const *y);
void fp_add3(fp *x, fp const *y, fp const *z);
void fp_sub3(fp *x, fp const *y, fp const *z);
void fp_mul3(fp *x, fp const *y, fp const *z);
void fp_sq1(fp *x);
void fp_sq2(fp *x, fp const *y);
extern long long fp_mulsq_count;
extern long long fp_sq_count;
extern long long fp_addsub_count;
static inline void fp_neg1(fp *x)
{
fp_sub3(x,&fp_0,x);
}
static inline void fp_neg2(fp *x,const fp *y)
{
fp_sub3(x,&fp_0,y);
}
static inline void fp_double1(fp *x)
{
fp_add2(x,x);
}
static inline void fp_double2(fp *x,const fp *y)
{
fp_add3(x,y,y);
}
static inline void fp_quadruple2(fp *x,const fp *y)
{
fp_double2(x,y);
fp_double1(x);
}
static inline void fp_quadruple1(fp *x)
{
fp_double1(x);
fp_double1(x);
}
static inline long long fp_iszero(const fp *x)
{
return uintbig_iszero(&x->x);
}
static inline long long fp_isequal(const fp *x,const fp *y)
{
return uintbig_isequal(&x->x,&y->x);
}
void fp_inv(fp *x);
// if x is a square: replace x by principal sqrt and return 1
// else: return 0
long long fp_sqrt(fp *x);
#include "randombytes.h"
#include "crypto_declassify.h"
static inline void fp_random(fp *x)
{
for (;;) {
randombytes(x,sizeof(fp));
uintbig diff;
long long accept = uintbig_sub3(&diff,&x->x,&uintbig_p);
crypto_declassify(&accept,sizeof accept);
if (accept) return;
}
}
#endif