+/*----- Binary field subgroups --------------------------------------------*/
+
+typedef gprime_param gbin_param;
+
+/* --- @group_binary@ --- *
+ *
+ * Arguments: @const gbin_param *gb@ = group parameters
+ *
+ * Returns: A pointer to the group, or null.
+ *
+ * Use: Constructs an abstract group interface for a subgroup of a
+ * prime field. Group elements are @mp *@ pointers.
+ */
+
+group *group_binary(const gbin_param */*gp*/);
+