Here's at least two options.
If you have to use your head you can try XKCD's famous Horse Staple Battery
Method: http://xkcd.com/936/
Generator - http://correcthorsebatterystaple.net/
Alternatively there's KeepassX (Same as Keypass but doesn't need Mono), plus
it's in the native repo so you don't have to worry about sketchy PPA:
http://packages.trisquel.info/search?keywords=keepassx&searchon=names&suite=toutatis§ion=all
Why to be weary of PPAs:
http://www.techrepublic.com/blog/linux-and-open-source/hand-of-thief-malware-could-be-dangerous-if-you-install-it/