RBAC role hierarchical auxiliary construction method based on prefix dictionary tree

The invention discloses an RBAC role hierarchical auxiliary construction method based on a prefix dictionary tree. The RBAC role hierarchical auxiliary construction method sequentially comprises the following steps of A, obtaining an access control instance set and a basic permission set of a department from a department information system; b, constructing all permission sets in the basic permission set into a prefix dictionary tree according to a mode of an interlayer permission set cardinal number sequence and an intra-layer permission set inverse linear sequence; and C, utilizing a hierarchical role discovery algorithm to simultaneously exclude the permission set containing a certain implicit precedent and not containing a certain implicit posterior in the main base, the permission setonly containing a certain implicit precedent and a certain implicit posterior in the main base and the permission set with the implicit posterior being empty, an implicit relationship set is obtained,and a role set is determi