Linux system is famous for its security for the network access and the users' management. But is there any way to secure the Linux local file system? The answer is YES! From the Linux core version 2.4.22, Linux has been added the support of encrypt the local Linux file system, called "Scatter list Cryptographic API", which is newly coming together with the Linux kernel version2.5/2.6.

To use this API to encrypt a Linux local file system, it needs another thing called “loop device”. Next we will talk about how to install this loop device and how to configure it to work.

Notes: it exits two versions of the “Cryptographic API”. The early one came as the patch of the Linux kernel 2.2 and 2.4; the latest one has been added since the Linux kernel 2.5/2.6, and it first show up with the version is 2.4.22.