Abstract: Due to the impact of information flow on system integrity, explored ways to enforce access control with consideration of information flow. Proposed a model for Access Control based on Source of Information Flow(ACSIE),in which, source of information flow refers to the entity that is a starting point of the flow. Source of information flow was expressed via set of users. Integrity level was described through sources of information flows. Dominance relationship of integrity levels was defined according to inclusion relationship of sets. Access control rules were constructed based on information flows. Integrity constrained subjects and constrained sets were introduced to improve adaptability of the model. Existing system information may be utilized effectively in implementing the model, hence, complexity of system configuration can be reduced,and system usability can be improved.

Key words: Access control,Information flow,Source of information flow,Usability