中文摘要：

针对传统的访问控制方法不支持动态授权和文件评价、且存在恶意再分享隐患,设计了一种支持动态授权和文件评价的访问控制机制（DAFE-AC）。DAFE-AC采用的动态授权机制能够对已授权用户进行实时监控,保证了用户之间的相互监督;采用的文件评价机制可以支持文件解锁阈值的动态更新。基于Hash/索引数据库,DAFE-AC确保了文件在系统中的唯一性。在DAFE-AC中,用户授权值会随着其他用户行为动态变化,且用户可以通过对文件进行评价以消除恶意再分享。

英文摘要：

Concering that the traditional access control methods fail to support dynamic authorization and file evaluation,and suffer from malicious re-sharing issue, an Access Control Mechanism with Dynamic Authorization and File Evaluation（ DAFE-AC） was proposed. DAFE-AC adopted a dynamic authorization mechanism to monitor authorized users in real-time and allowed users to supervise each other. The file evaluation mechanism in DAFE-AC could dynamically update the access threshold of files. Based on the Hash / index database, DAFE-AC can ensure the uniqueness of files in the system. In DAFEAC, a user＇ authorization value can dynamically change with behaviors of other users, and users can perform file evaluation to eliminate malicious re-sharing of files.