Abstract: Identity code is introduced to represent roles and rights, while the synthesis of identity code represents the inheritance of roles as role derivation information. It provides security management on role authorization, role inheritance and data access authorization and it can adapt to a dynamically changing environment. Several special security requirements such as role private attribute and multi-role access control can also be satisfied. The scheme provides a more efficient authorization to simplify the management of access control and it can be applied better in large-scale network application.