The Linux port of KeePass is called
KeePassX.
The following knowledge base article discusses the encryption mechanisms involved with securing keepass databases.
http://keepass.info/help/base/security.html
That's a good read and I highly recommend everyone read it. It tells you about mitigating brute force attacks by modifying iterations of hashes. It even has a little button that computes 1 seconds worth of hashes automatically so that it takes one second...