bn_mp_mulmod.c 524 B

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  1. #include "tommath_private.h"
  2. #ifdef BN_MP_MULMOD_C
  3. /* LibTomMath, multiple-precision integer library -- Tom St Denis */
  4. /* SPDX-License-Identifier: Unlicense */
  5. /* d = a * b (mod c) */
  6. mp_err mp_mulmod(const mp_int *a, const mp_int *b, const mp_int *c, mp_int *d)
  7. {
  8. mp_err err;
  9. mp_int t;
  10. if ((err = mp_init_size(&t, c->used)) != MP_OKAY) {
  11. return err;
  12. }
  13. if ((err = mp_mul(a, b, &t)) != MP_OKAY) {
  14. goto LBL_ERR;
  15. }
  16. err = mp_mod(&t, c, d);
  17. LBL_ERR:
  18. mp_clear(&t);
  19. return err;
  20. }
  21. #endif