Usually all your files like phone numbers, love letters, bank account data etc. are stored in plaintext on your computers harddisk. All the data is accessable by anyone who has access to the harddisk. This is very bad in case someone you don't trust has your harddisk. E.g. a thief that steals your notebook, or breaks in your house or company. If the thief has your disk he/she can also read all the files that where saved on it, no matter if you have a login password - the files are always stored in plaintext.
The CryptoBox brings easy to use data encryption to your computer. This works out of the box and doesn't need complicated configuration steps.
Here comes a small usage example for the CryptoBox with a discarded PC as fileserver:
You boot up the old PC with the CryptoBox live-CD. After the completed boot process you can access it with your browser via network. Then you partition and reformat the harddisk of the old PC with encryption support. Therefore you provide a passphrase. This is all done through the user friendly webinterface. You can also plug in an external harddisk and use this for encrypted data storage. Afterwards you copy your sensitive data over the local network to the CryptoBox. It is stored on its harddisk in a secure way. Nobody can access the data, without giving the right passphrase before.