1 files changed, 23 insertions, 0 deletions
diff --git a/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_invmod.c b/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_invmod.c
new file mode 100644
index 00000000000..7b35a243190
--- /dev/null
+++ b/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_invmod.c
@@ -0,0 +1,23 @@
+#include "tommath_private.h"
+#ifdef BN_MP_INVMOD_C
+/* LibTomMath, multiple-precision integer library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
+
+/* hac 14.61, pp608 */
+mp_err 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;
+   }
+
+   /* if the modulus is odd we can use a faster routine instead */
+   if (MP_HAS(S_MP_INVMOD_FAST) && MP_IS_ODD(b)) {
+      return s_mp_invmod_fast(a, b, c);
+   }
+
+   return MP_HAS(S_MP_INVMOD_SLOW)
+          ? s_mp_invmod_slow(a, b, c)
+          : MP_VAL;
+}
+#endif