Ext2Crypt is an ext2 based filesystem which stores the data on block devices in encrypted form. It makes use of the cryptography API present in the Linux kernel. Ext2Crypt requires 2.6.4 (or above) kernel with cryptography enabled (specifically MD5 and DES). It also requires OpenSSL be installed on the machine inorder to compile the tools provided along with the file system.

Ext2Crypt offers security at two levels.

1.		It requires the user to provide a password while formatting the drive using the provided utility namely mke2fs . The user is again asked for this password when she tries to mount the drive using the ext2crypt_mount utility. Only if the two passwords match is the user able to mount the drive.
2.		The data pertaining to files is encrypted using the DES algorithm in the kernel before it is written to the drive and is decrypted using the same just before it is copied to the userspace programs. The advantage of this paranoid approach is that even if the pages pertaining to the files are swapped out due to lack of physical memory, they get swapped out in encrypted form. Hence if a black hacker tries to read the swapped out data from the swap area it won't make any sense to her since it won't pass thru the ext2crypt file system module. NOTE: Currently only the files on the block device are stored in encrypted form. I plan to encrypt the directories as well as the meta information pertaining to the file system in the future releases of the software.

You man download the file system along with the tools by going here. For any suggestions or help regarding the file system you make drop me a mail at vishpat AT users DOT sourceforge DOT net.