StickWiki is a small lightweight portable wiki that is standalone and operates from a single xhtml file. It offers AES encryption as well. It isn't that large and has built in documentation for making and adding pages, links, etc. It certainly has a different approach compared to TiddlyWiki in terms of function and interface. I recommend this as an alternative to TiddlyWiki, if not for the encryption features.
Wiki on a Stick!
StickWiki Project page @ sourceforge