Truecrypt is helpful if you use wvdial, for example, because wvdial puts your password in plain view in the files ~/.wvdialrc and /etc/ppp/chap-secrets. If someone steals your laptop, they can simply read your ISP password by booting from a live disk. Or by just taking out your disk and putting it into their USB craddle. If you put the files on an encrypted disk, they cannot.
While there is Linux software that does equivalent things, with Truecrypt you can open the disks using both Windows and Linux.
To get Truecrypt, go to truecrypt.org. Then
gunzip ....tar.gz tar xvf ....tar chmod u+x truecrypt-...-setup-ubuntu-x86 truecrypt-...-setup-ubuntu-x86
gunzip ....tar.gz tar xvf ....tarThen make sure you have the right version of your kernel. In a terminal:
uname -rNow use synaptic to get linux-headers (two packages), linux-kbuild, and linux-source for that kernel. Look in the installed files. You may have to go to /usr/src and unzip the sources manually; that was not done on my Debian system.
KERNEL_BUILD=/usr/src/linux-headers-2.6.21-2-686Similarly, the other three files were all in /usr/src/linux-source-2.6.21 so I also set
KERNEL_SRC=/usr/src/linux-source-2.6.21Then I went through build.sh and wherever it would want to start remaking kernels, I put an exit. The changes are marked with "Leon". After that, it was safe to follow the installation instructions. The kernel sources can be deleted after making truecrypt to save disk space. Leave the truecrypt sources; you may have to do it again if you change your kernel.
To create a file /sctdat.tc to hold your secret files on a "disk" named /sct, in a terminal, enter the commands
sudo -u root mkdir /sct sudo -u root truecryptThen select "create" to create the file /sctdat.tc. To be able to read the disk using MS Windows, use filetype FAT. Alternatively, try ext2 and install ext2ifs on Windows. If you have a multi-user setup, or allow outside access, you may need to avoid NTFS, since file protection is crippled with NTFS. At the time of writing you can only create NTFS disks from Windows anyway.
To mount the disk, use
truecrypt /sctdat.tc /sct
Note that you can also run Truecrypt from the Applications/ Other/ menu. It will prompt you for your password as needed. Note that you may need to enter both the disk password and your account password: keep them apart. If the disk file is in the header, you disk password is needed.