Just some ideas for you in securing a TiddlyWiki document for future reference. I use Truecrypt (
http://www.truecrypt.org/) to create an encrypted storage area that can be mounted as a drive letter. I just put anything I want secured there. That way you only have one password for all of the contents you have there, including a TiddlyWiki document. Also, I suggest you use a password manager like LastPass or KeyPass (
http://keepass.info/) where you only need to remember one password for all of your other passwords. You can store your Truecrypt password there so if you forget it, you can go to your password manager and view it. (So long as you don't forget the master password to the password manager software!)