dropbear/libtommath/bn_mp_invmod.c
Steffen Jaeckel 615ed4e46a update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
* make key-generation compliant to FIPS 186.4

* fix includes in tommath_class.h

* update fuzzcorpus instead of error-out

* fixup fuzzing make-targets

* update Makefile.in

* apply necessary patches to ltm sources

* clean-up not required ltm files

* update to vanilla ltm 1.1.0

this already only contains the required files

* remove set/get double
2019-09-16 21:50:38 +08:00

41 lines
1.1 KiB
C

#include "tommath_private.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.
*
* SPDX-License-Identifier: Unlicense
*/
/* hac 14.61, pp608 */
int mp_invmod(const mp_int *a, const mp_int *b, mp_int *c)
{
/* b cannot be negative and has to be >1 */
if ((b->sign == MP_NEG) || (mp_cmp_d(b, 1uL) != MP_GT)) {
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) == MP_YES)) {
return fast_mp_invmod(a, b, c);
}
#endif
#ifdef BN_MP_INVMOD_SLOW_C
return mp_invmod_slow(a, b, c);
#else
return MP_VAL;
#endif
}
#endif
/* ref: HEAD -> master, tag: v1.1.0 */
/* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
/* commit time: 2019-01-28 20:32:32 +0100 */