The complete database is always encrypted either with AES (alias Rijndael) or Twofish encryption algorithm using a 256 bit key. Therefore the saved information can be considered as quite safe. KeePassX uses a database format that is compatible with KeePass Password Safe. This makes the use of that application even more favourable.
Originally KeePassX was called KeePass/L for Linux since it was a port of Windows password manager Keepass Password Safe. After KeePass/L became a cross platform application the name was not appropriate anymore and therefore, on 22 March 2006 it has been changed.