http://www.appcove.com/passtool/

AppCove developed a very simple user interface to the excellent gibberish-aes encryption library.  This tool allows you to enter a passphrase, some text to encrypt, and encrypt it right in your browser.

No data is sent to the server — AppCove is never aware of the passphrase, plain text, or cipertext.

We use this tool to encrypt passwords and other information so that it can be stored in should-be-secure locations (like Google Sites or gmail).  

Enjoy!