User-role assignment of RBAC by propositional formula based on NTFS

As of many advantages, Role-based Access Control (RBAC) is considered the most flexible access policy. However, for there is no mature form language to support it, RBAC is not applied completely till now. By analysis of New Technology File system (NTFS) widely used in Windows NT, The paper proposes method to realize RBAC by NTFS in file and folder security management. The logic condition for user-role assignment was studied with the help of role table and permission matrix firstly, and then a propositional formula which computes user-role was putted forward. The model works for making effective and accurate decision to user-role assignment of RBAC.