XExt3: The Design and Implementation of a Security Enhanced Ext3 File System

In this paper we develop an extended Ext3(XExt3) which means security enhanced file system. It can be used in generic Linux systems or trusted operating systems (TOS) as a file system. The XExt3 file system can protect data of a computer system from physical theft by encrypting them. We concentrate on balancing security, transparency and portability while minimizing computational overheads. For security and transparency, the XExt3 supports file protection, Linux group sharing, and the minimization of interactions between users and the system. In the aspect of performance, we minimize the overheads by implementing the proposed method on a native Ext3 file system in a Linux operating system. Finally we implement our system as a Linux kernel module for high portability. Our experimental results show that the XExt3 is about 3 or 4 times faster than previous cryptographic file systems.