jkPassword was made from a desire to replace previous smart-phone (Treo) functionality for the iPhone. One of the main purposes we used the Treo for was password and information storage. However, since iPhone doesn't currently allow for 3rd party applications we had to figure out a way to make it work as a webpage but act like an iPhone application.
By implementing the encryption on the iPhone in Javascript and then only sending the encrypted versions we were able to make a solution that is not only more secure but "backed" up at the same time.
Many thanks to Joe Hewitt, for his inspiration on the Navigation demo. Sorry Joe, IUI was released after we already significantly hacked up the original demo.