44 lines
1.0 KiB
C
44 lines
1.0 KiB
C
#include <tommath.h>
|
|
#ifdef BN_MP_INVMOD_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.
|
|
*
|
|
* The library is free for all purposes without any express
|
|
* guarantee it works.
|
|
*
|
|
* Tom St Denis, tomstdenis@iahu.ca, http://math.libtomcrypt.org
|
|
*/
|
|
|
|
/* hac 14.61, pp608 */
|
|
int mp_invmod (mp_int * a, mp_int * b, mp_int * c)
|
|
{
|
|
/* b cannot be negative */
|
|
if (b->sign == MP_NEG || mp_iszero(b) == 1) {
|
|
return MP_VAL;
|
|
}
|
|
|
|
#ifdef BN_FAST_MP_INVMOD_C
|
|
/* if the modulus is odd we can use a faster routine instead */
|
|
if (mp_isodd (b) == 1) {
|
|
return fast_mp_invmod (a, b, c);
|
|
}
|
|
#endif
|
|
|
|
#ifdef BN_MP_INVMOD_SLOW_C
|
|
return mp_invmod_slow(a, b, c);
|
|
#endif
|
|
|
|
return MP_VAL;
|
|
}
|
|
#endif
|
|
|
|
/* $Source$ */
|
|
/* $Revision$ */
|
|
/* $Date$ */
|