-int EC_GROUP_do_inverse_ord(const EC_GROUP *group, BIGNUM *res,
- BIGNUM *x, BN_CTX *ctx)
+/*-
+ * Default behavior, if group->meth->field_inverse_mod_ord is NULL:
+ * - When group->order is even, this function returns an error.
+ * - When group->order is otherwise composite, the correctness
+ * of the output is not guaranteed.
+ * - When x is outside the range [1, group->order), the correctness
+ * of the output is not guaranteed.
+ * - Otherwise, this function returns the multiplicative inverse in the
+ * range [1, group->order).
+ *
+ * EC_METHODs must implement their own field_inverse_mod_ord for
+ * other functionality.
+ */
+int ec_group_do_inverse_ord(const EC_GROUP *group, BIGNUM *res,
+ const BIGNUM *x, BN_CTX *ctx)