It all depends what your needs are. If you plan to backup the data on dvd, and wish to keep it encrypted on dvd -
urpmi mountloop
then open the application called drakloop (it gets installed with mountloop). create a folder decide on encryption methods eg aes 196 and keep all your encryption with the same choice to simplify remounting and so on.
When you mount the drakloop folder, it appears as a usual ext3 partition with all your lovely data that made gives your company the edge in the market. When you unmount it, your competitors have no idea what is on that "partition" - they only see and "ENCFILE" - a soldid hunk of nothingness except for the size of the data. no otehr info is accessible.
To burn to dvd as encrypted data, merely unmount the folder then burn the encrypted file (to my recollection it is named "encfile")
using K3B or any other burn software. The dvd now contains the encrypted file which can only be decrypted with the key u provided. You can now mount the drakloop folder again and delete that data - use it for other data, and then unmount and bakkup to dvd again.
To mount the same file from the dvd, you have the option of using the terminal or the easiest way IMHO is to create a special 4.3 GB drakloop (encfile) folder "partition" (drakloop partition/folders reside in your home folder). i name it "dvd" and use it only for accessing older bakked up data. I suggest you keep this "drakloop dvd folder" for mounting any "encfile" that's stored on your dvds or whatever media u use. Make sure that your dvd folder is not mounted by drakloop/unmount the "dvd folder". Now simply delete any encfile that exists in the "dvd" drakloop folder and copy the encfile from your dvd to the dvd drakloop folder. once the copy is finished, mount the folder using drakloop and u see your decrypted data from the dvd. It's that simple.
One problem is that it seems mandriva will not be supporting this mountloop package for much longer because of some security loophole - darned if i understand it. :( It's unfortunate and i request mandriva to please continue to have us choose between mountloop and other options notwithstanding there may be some security risk. we can make that choice as end users can't we?
The other option is gpg - but thene each file must be encrypted on its own. it's tiresome.
the other option is truecrypt or realcrypt. Realcrypt is easy enough to install but it takes years to master the use of it for me. so i tried truecrypt because it has a gui. No can install/compile so far. very hard to compile truecrypt in mandriva. Please can someone either request that mountloop continue to remain available because it works like a symphony for most people. alternatively, create a gui for realcrypt.
What i have done for now is installed FEDORA 9 - from install, u can encrypt not only your home partition, but your root as well. The only un encrypted section is about 198MB for the boot. The rest is encrypted and its all done by a simple check in a box. you must install from the dvd and its easiest to select a partition and have anaconda (fedora installer) provide a default LVM setup on a partition.
Truecrypt is easy as pie to install in fedora 9 (an unofficial rpm is available). The unofficial rpm gives the full truecrypt functionality - hidden or non hidded folders can be created/data encrypted "on the fly"/unencryoted/burned to disc/remounted same as drakloop, only it is sure to be maintained and readable on all distros (even the smutty closed source ones)
For now, i am sold on fedora for their one touch encryption at install