Abstract: Real time backup system has a high restriction on the dynamic. Due to the shortages of the existing access control models in the granularity of the model elements and the dynamic allocation of rights, the security of backup system will be influenced. The concepts of temporal and environment and the definition of action are given to describe the access activities, a quantified action-based access control (QABAC) model for real time database backup system is proposed. The concepts of quantified attribute and trust degree are introduced firstly, the security degree of the access behavior is calculated by using the quantitative function to dynamically quantify the attributes, and then the trust degree of the access behavior is allocated according to the quantitative results. Finally authorization policy determines the access behavior through the trust degree. Compared with other traditional models, the QABAC model is more flexible， more secure, and more suitable for the current open network environment to protect the backup database security.

Key words: access control, quantified action, fine-grained, dynamic authorization