41 lines
981 B
C
41 lines
981 B
C
#include "tommath_private.h"
|
|
#ifdef BN_MP_DR_IS_MODULUS_C
|
|
/* LibTomMath, multiple-precision integer library -- Tom St Denis
|
|
*
|
|
* LibTomMath is a library that provides multiple-precision
|
|
* integer arithmetic as well as number theoretic functionality.
|
|
*
|
|
* The library was designed directly after the MPI library by
|
|
* Michael Fromberger but has been written from scratch with
|
|
* additional optimizations in place.
|
|
*
|
|
* SPDX-License-Identifier: Unlicense
|
|
*/
|
|
|
|
/* determines if a number is a valid DR modulus */
|
|
int mp_dr_is_modulus(const mp_int *a)
|
|
{
|
|
int ix;
|
|
|
|
/* must be at least two digits */
|
|
if (a->used < 2) {
|
|
return 0;
|
|
}
|
|
|
|
/* must be of the form b**k - a [a <= b] so all
|
|
* but the first digit must be equal to -1 (mod b).
|
|
*/
|
|
for (ix = 1; ix < a->used; ix++) {
|
|
if (a->dp[ix] != MP_MASK) {
|
|
return 0;
|
|
}
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
#endif
|
|
|
|
/* ref: $Format:%D$ */
|
|
/* git commit: $Format:%H$ */
|
|
/* commit time: $Format:%ai$ */
|