A Formal Method Based Case Study for Access Control

River crossing problem is a typical logic puzzle. In the puzzle, the members should cross from one river bank to another abide by some restrictions. This kind of puzzles can be seen as access control problems from the logical point of view. The analysis could help to specify suitable constraint strategies for design access control systems. In this paper, case studies are carried out for the idea mentioned above. Hope the exploration could be valuable reference for research of access control.