Abstract: The emphases of traditional access control studying is the policy of authorization, the studying is focus on how to distribute permissions to subject and how to restrict the using of these permissions. Based on the analysis of traditional access control, we introduced a new mode,QUCON,which is based on the UCON and has the ability to judge the character of accessing. By introducing assure obligations, unsure obligations, assure conditions, unsure conditions,characters and active rules,the QUCON has the ability to judge accessing subjectively,thereby reduce or exclude those threats from the illegal users who has permission.

Key words: Information security, Access control, Usage control, Character