Encrypted storage

In case you have documents and files you don't want anyone to be able to see there is always the possibility to use truecrypt. Truecrypt will let you use a file or partition as an encrypted storage. It is easy to use and not at all hard to understand. It also supports Linux, Windows and Mac so you can use it on whatever platform you wish.

Truecrypt is no longer safe.
Check their website before using it.

You can even encrypt part of an USB-pendrive and include the files for running the truecrypt program on the USB-drive. This way you will be able to use you USB-device on other computers without needing to install the package on the computer you are working on. (But you will need admin privileges.)

To download TrueCrypt head over to their web-site. Go to the download page and download the package for your platform. After downloading the Linux gzipped tarball you simply extract it and run the truecrypt installation-file.

Step 1:
Run truecrypt to open the GUI for the program and create a new encrypted volume. Using a file is as it can be. Click on Create Volume, select the folder to put the file in, and give it a filename. Follow the instructions to set the encryption, password and any other option.

Step 2:
In the TrueCrypt main window select the slot you want to put your encrypted volume in, click on Select File and navigate to the file you created in the previous step. Click on Mount and type your password for the encrypted filesystem when prompted.

Step 3:
Add files or folders to your encrypted filesystem as you do to any filesystem.

That's all there is to it.
Easy and well functioning way of keeping some documents private.
To use a portable USB-drive check the documentation on TrueCrypt web-site.